USING MOBILE AGENTS FOR OFF-LINE COMMUNICATION AMONG MOBILE HOSTS IN A LARGE, HIGHLY-MOBILE

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Mobile-Agents for Distributed Market Computing

Mobile-Agents for Distributed Market Computing Shinji Tanaka,Hirofumi Yamaki,and Toru IshidaDepartment of Social Informatics,Kyoto UniversityKyoto,606-8501,JAPANstanaka,yamaki,ishida@kuis.kyoto-u.ac.jpAbstractThis paper discusses the implementation using mobile agent and the performance of the market computing to allocate network quality of service most efﬁciently,based on users’preference.Though the protection of users’private preference and the efﬁcient calculation are both important,these two requirements often contradict each other.By implementing QoS Market,a market-based network resource allocation system,using mobile agents,the com-munication time between agents and an auctioneer,which is the largest overhead in market computing,is reduced dramatically whthout leeking users’privacy information. The result of experiments show a mobile agent approach is more efﬁcient then others,and the overhead of one market computing cycle in this system is about450msec,which means that the system achieves sufﬁcient efﬁciency.1.IntroductionIn usual networks such as the Internet,a number of users share the network resource,which causes the users’demands frequently conﬂict.In such an environment,the importance of a communication link varies according to the application and its usage,but network control policy of”best-effort”type,such as CSMA/CD,fails to consider such an aspect.What we need here is a resource allocation policy that reﬂects users private preference and allocates limited network resource efﬁciently.We have already proposed an approach which is based on a competitive price mechanism explained by general equilibrium theory[10].In our model,the preference of users and the characteristics of application programs are represented by consumer and producer agents respectively. Each agent updates their bids based on the price of goods, which is determined by the pricing mechanism of the market to balance demand and supply.A Pareto optimal resource allocation is obtained as the result of the interaction[2].Our challenge here is to calculate such an efﬁcient resource allocation in a practical length of time without leaking users’private information about preference for applications.A market-based algorithm generally consists of a large number of iterations to derive an equilibrium that balances the demand and the supply of goods,which results in a slow response to the given environment.The situation of the network used by a number of people, however,changes dynamically according to the change in the usage of application programs.This dynamics allows the allocation system only a few seconds of delay at the most.In previous research[9],we applied the market-based mechanism into FreeWalk[5],a multimedia desktop meet-ing environment with shared virtual3D space(Figure.6), and controled the transmission of pictures.In this exper-iment,the whole allocation system is implemented in a single process in order to suppress the number of messages exchanged via network and achieved a practical quality of allocation in real-time.This approach,however,makes the users’private preference in its nature,leak to the auctioneer, which is a part of the market mechanism that modiﬁes the price according to the demand.To resolve this problem,this paper proposes an approach to implement a group of agents as a mobile agent that dynamically changes its place to an appropriate position. By moving agents to the server where the interaction among agents is performed,the users’privacy is preserved while keeping the smallest delay of the allocation.We have implemented a market-based network resource allocation system with mobile agents on Windows NT, and validated the above scenario by performing several experiments.2.Market-Based Resource AllocationIn this section,we present the general idea of market-based network resource allocation and the algorithm of the market calculation.2.1.QoS Market ModelOur approach to achieve efﬁcient resource allocation by merging various preferences of individual users is to introduce a market mechanism.Below,we describe the framework of our market-based application QoS control as the basis of the implementation issues discussed in this paper.The two basic ideas to construct a market model for QoS control are as follows.ers evaluate application QoS,which is the qualityof service provided by network application programs, rather than the raw network resource,such as band-width,that they use.2.We distinguish the“current”and the“future”networks,so that inactive users can obtain the incentive to transfer their rights to use current network resources to other active users,in exchange for the rights to use future network resources.Figure1shows the market model for application QoS allocation.The rectangles in theﬁgure represent the goods exchanged in the market.There are two types of goods, bandwidth and QoS,and each of them is divided into current and future goods.CBW and FBW stand for current and future bandwidth respectively,which are both shared by all the users.The QoS of the communication from user j to user i is represented by,and stands for the QoS that is received by user i in the future.The future QoS is assumed to be a single good for simplifying the model.The circles in theﬁgure are agents.Those on the left are consumer agents each of which represents the preference of each user,and those on the right are producer agents, each of which represents the conversion from bandwidth into application QoS performed by application programs.The speciﬁcs of this model,such as the modeling of user preference and application performance,and the evaluation of resource allocation by simulation have been reported in our previous work[10].2.2.Algorithm for Computing EquilibriumIn this market-model,there are two types of elements: agents and auctioneers.Figure2shows messages ex-changed in the market.The underlying model of network usage is single-cast communication with network resource reservation mechanism,such as an intranet with RSVP[1] support.A consumer agent represents user’s preference,which is modeled as a utility function that takes a bunch of goods consumed as its input and returns a higher value for moreFigure1.QoS Market Modelpreferred bunch.There is a one-to-one correspondence between a user and a consumer agent.The user informs his/her preference on application QoS to the corresponding consumer agent(preference message),which reﬂects it in the utility function,typically by changing coefﬁcients in the formula.Each consumer acts to acquire a bunch of goods that maximizes the value of the utility function(we call this value as just“utility,”hereafter),by changing the bid for the goods in its interest.A producer agent represents the characteristic of a net-work application program,which transforms raw network resource into a service to be consumed by the user.Thus, there is a one-to-one correspondence between a producer agent and a service that is provided by an application pro-gram.Note that multiple services can be provided by a single program and that a single service can consist from multiple type of network resources.There is no one-to-one correspondence between a program and a producer agent, nor between a producer agent and any single type of network resources.The transformation from network resources to an application service is modeled as a production function, which takes the set of network resources as its input and output the corresponding service.When a service starts or ﬁnishes,a user provides or erases the agent which is cor-responded the service(service message).Each producer selects its production level so as to maximize its proﬁt, 2bidprice of goodsresults of calculationchange of preference or service AuctioneerAgent(Consumer)User(preference/service)(result)(price)(bid)trade matrix(trade)Figure 2.Message Exchangewhich is deﬁned as the difference between the income ob-tained by selling the services and the cost to purchase the network resources.An auctioneer exists for each good.It adjusts the price of a good based on the bid from consumers and producers,so as to balance supply and demand of the corresponding good.The adjusted price is then sent to the agents and used by them to change their bid.The market calculation in this model is performed as follows (Figure 3).1.The auctioneer reports price of goods to agents(price message)(l.3).2.Each agent calculates supply or demand of goods based on price information,to maximize their utility or proﬁt(l.4).They then report them to the auction-eer(bid message).3.The auctioneer aggregates the supply and the demand of goods reported by agents(l.5),and raises (lowers)the price if the demand is over (under)the supply(ll.6–13).4.If the difference between the supply and the demand is under the threshold,which is decided by users,the calculation terminates and the price exactly reﬂects the ﬁnal allocation of network resources(l.15).If not,the auctioneer and the agents repeat from 1.1:repeat 2:begin3:Actioneer reports price to agents;4:Agent calculates supply or demand;5:Auctioneer aggregates supply and demand;6:if(supply over demand)then 7:begin8:Auctioneer raises price;9:end10:if(supply under demand)then 11:begin12:Auctioneer lowers price;13:end 14:end15:until(|supply -demand|>threshold);16:17:Agent calculates its share of bandwidth;18:Agent reports it to QoS Client;Figure 3.Market Calculation5.When the calculation terminates,each producer agent calculates its share of network resources based on the ﬁnal price,and reports it to QoS Client to control the communication of the corresponding application pro-gram (resource message),which uses the network resources and provides services to users(l.17,18).The allocation has to be recalculated to adapt to the dynamically changing environment,and thus the above process (“calculation cycle”or just “cycle”hereafter)is re-peated on every recalculation.If the overhead of computing equilibrium is large,resource allocation cannot follow the change of environment,not to mention that market com-puting itself occupies a considerable size of resource both in the network and computers.Therefore,the overhead of market computing should be as small as possible.The resource message,which is used for auctioneers to report resource allocation to users,is transmitted when-ever the auctioneers ﬁnish calculation.The preference message is used for users to report changes of their pref-erence to agents,while the service message is used for network applications to report the changes in the ser-vices they provide to agents.The service message is transmitted whenever the behavior of application programs changes as well as the start of a new process.The num-ber of above messages exchanged in the market computing is comparatively small compared to the messages deﬁned below.The price message is used for the auctioneers to report the price of goods to agents,and the bid message is used for agents to report the supply and the demand for goods.Both of them are transmitted whenever price of goods are 3changed,thus the number of these messages exchanged is largest among other messages(typically,10to100times the number of agents in a calculation cycle).To minimize the overhead of market calculation,reducing the number of these two types of message is effective.3.ImplementationIn the rest of this paper,we present the underlying implementation issues,and discuss the implementation with mobile agents to our market-based network resource control system.3.1.Mobile Agent ApproachIn our market-based approach,agents send the auction-eers their bids,which are derived from the preference or the usage of network application program by users.Since users are distributed over network,there are typically two possible approaches to implement the agents.Theﬁrst one is to implement each agent in the host of the corresponding user,which is called distributed imple-mentation with static agents(Figure4(a),messages in the ﬁgure are the same asﬁgure2)here.In this case,since the calculation for generating bids can be performed simultane-ously in their hosts,processors in the network are utilized effectively.On the other hand,as described in the previous section,all the bid and the price messages transmit-ted between agents and the auctioneers are performed as network communications,which causes large overhead in market computing.We formulate this overhead as follows.Assume that the number of clients is,and the number of calculation cycles necessary for market to reach an equilibrium is.If the time to send and receive price information of goods is, the time that agents calculate the most suitable supply and demand of goods is,the time to transmit supply and demand of goods is,the time for the auctioneers to adjust price of goods is,and the time to transmit the results of calculation to users is,then the time of one calculation cycle is given as follows.(1)The second approach is to implement all the utility functions in the host where the auctioneers reside.This is called centralized implementation(Figure4(b)).In this case, the utilization of computation resource is worse than theﬁrst approach,while the communication cost is minimized.Assuming the time to send and receive price information of goods is and the time to transmit supply anddemand of goods is,then the time of one calculation cycle is given as follows.(2)The difference of one market calculation of equilibrium time between the case of distributed implementation(with static agents)and the case of centralized implementation is given as follows.1(3) The balance between the time to transmit the bid and the price messages,and the time to derive bids based on the maximization problems of the agents determine which approach is suitable.In current network environment,it is obvious that the former surpasses the latter.This fact makes the distributed implementation far more costly than the centralized implementation.In the centralized implementation,utility and production functions are deﬁned statically in the same process as the auctioneers(“market server”hereafter).Users report their preference on applications by sending coefﬁcients to be set in the functions to the auctioneers.Although this approach is relatively simple,the available utility function cannot be changed,which prevents the users from setting various types of preference,thus the system designer has to know all the types of user preference.Since the privacy problem is serious in the centralized implementation,we examine the following two approaches by extending the distributed implementation with static agents.1.Remote agent approach(Figure4(c)):Agents areimplemented in the market server,but utility functionsand production functions can be changed dynamically.Users send the expressions of utility and productionfunctions to the market server.The expressions areinterpreted by the remote agents.2.Mobile agent approach(Figure4(d)):A group ofagents is implemented as a mobile agent which keepsutility functions and production functions inside,andmoves to ers send their preference onapplications to their own agents.Theﬁrst approach provides moreﬂexibility than the cen-tralized implementation.However,this approach uncovers the users’private preference,which is not preferable in the context of the market-based approaches,where minimal 4Figure4.Implementation Modelinformation is sufﬁcient to achieve the optimality of the whole system.The second approach conforms both of above require-ments,ﬂexibility and privacy.It can implement dynamic change of user preference and network usage by nature,and security issue in mobile agent systems has been discussed extensively in the preceding work[7].A mobile agent is a process object that can travel from one place to another in the middle of its execution preserving its context,and continue to run in the new place.A mobile agent can interact with the place it visits or with other mobile agents.Some of such environments provide a bidirectional authentication mechanism,where the servers authenticate the agents to protect themselves against malicious agents while the agents authenticate the servers.These features enables our market-based allocation mechanism to achieve the efﬁciency and theﬂexibility of market calculation resolving the security issue that the users’preference must be kept private.3.2.QoS MarketThe system called QoS Market that we implement adopts mobile agents to solve the problem of computing equilib-rium shown in the previous subsection.Below,we explain the conﬁguration of QoS Market,and the message interactions performed in it.Figure5shows the conﬁguration and the messageﬂow of the system.The messages in theﬁgure are the same as ﬁgure2.The system consists of three types of processes :QoS Client,Mobile Agent,and Auctioneer.The arrowsindicate the interaction among them,including the move of agents and theﬂow of information,such as bids,price and resource allocation.Their functionality is as follows.1.QoS ClientA QoS Client locates at each user’s local computer,provides user interface to obtain preference from itsuser.A QoS Client tells the user’s preference andthe usage of network application to the correspondingMobile Agents.It also receives the result of marketcomputing,i.e.,the allocation of network resource,and controls the transmission of data performed by thenetwork application programs.2.Mobile AgentA Mobile Agent includes a consumer agent that rep-resents its user’s preference,and producer agents thatrepresent application programs,and participates inmarket calculation generating bids based on currentprice information.The move of a Mobile Agent tothe market server is done only once when its userstarts QoS Client.The update of utility or productionfunctions is done by receiving parameters from thecorresponding QoS Client.A Mobile Agent informsthe current resource allocation at the end of everycalculation cycle.3.AuctioneerAuctioneers reside in the market server,and performthe adjustment of the price of goods.In our currentsystem,they are implemented as a single thread that 5MigrationFigure5.System Configurationhandles all the goods.The thread judges the conver-gence of the resource allocation,and tells the end of a cycle to all Mobile Agents.All these components have been implemented on Win-dows NT,and,except for the move of mobile agents,the network communication are performed using Microsoft’s Distributed COM(DCOM)technology,which extends the Component Object Model(COM)to support communica-tion among objects on different computersEven though many mobile agent systems are being devel-oped,such as Aglets,Odyssey,and V oyager[4,3,6],most of them are based on Java,Tcl or other interpreters,thus are not suitable for our application where the overhead in computation is critical.We decided to implement a subset of a mobile agent system with the minimal set of functionality, using Microsoft’s ActiveX technology,a Component Object Model optimized for a network,on WindowsNT.A group of agents is implemented as an ActiveX component,which are downloaded from the client processes to the market server and run as a part of it.Atﬁrst,a mobile agent exists as a DLLﬁle,a Dynamic Link Library,at each client.When a user logs in the QoS Market,the user sends the information about his/her mobile agent to the market server.Then the market server down-loads the DLL of mobile agent.The market server links the DLL dynamically,and initializes the mobile agent.After this,the mobile agent communicates the QoS Client,and receives the information about the preference of the user and applications,then provides a consumer and producers. In market calculation,the communication between the mar-ket server and the mobile agent is executed by the market server’s calling a function of the mobile agent.Because the mobile agent by ActiveX is written in native code,to know users’utility function,which is privacy,we have to analyze the code by reverse engineering,or presume from the answers of the mobile agent to various questions.These usually require a great deal of time,and we think this mobile agent is secure enough.Since the component of ActiveX moves without context, we do not assert that this is an ideal mobile agent system.Actually,this made our design of the agent interactions a little tricky,and we think this is a temporary,but practical enough for evaluating the feasibility of the mobile agent approach.We plan to adopt other mobile agent systems with more run-time efﬁciency in the future.4.ExperimentHere,we examine the performance of QoS Market in order to verify the mobile agent approach to the market-based network resource allocation.4.1.SettingsTo estimate the system performance,we make two ex-periments as follows.1.The evaluation environment consists of two PCs withWindows NT4.0.The market server is running at HostB.They are connected by10Mbps Ethernet,and the 6Figure6.FreeWalk:A Multimedia Conferenc-ing Tooldata have been recorded at Host A without the market server.Two applications on Host A communicate Host B,so there are two communication from Host A to HostB.Thus there areﬁve goods,which are CBW,FBW,1,which represents the one of the commnunication from Host A to Host B,2,and FQoS.To estimate the system performance,we measured the time for the calculation and the communication performed in each stage of a market calculation cycle.This is to estimate the difference between the mobile agent approach and the static agent approach.2.Evaluation environment consists of three PCs withWindows NT4.0.The FreeWalk,a multimedia con-ferencing tool,is running at each host,and the market server is running at one of them.They are connected by10Mbps Ethernet,and the data have been recorded at the two hosts without the market server.In this environment,only one user change his/her preference,while the preference of the other two users is kept unchanged.Since there are three users in the 3D meeting space,two network services are provided to each user.The user inputs his/her preference on these services as a ratio of their importance.The user inputs twenty times a random ratio of impor-tance of one service every three seconds.A ratio of importance of another service is set the rest ratio.To estimate the system performance,we measured the deviation in the resource allocation,which is caused by the delay of market computing.When the user changes his/her preference,there is always a certain amount of delay before the new resource allocation that reﬂects the change is derived.During this period,networkTable 1.The Times for Each Stage of theCalculationStatic MobileAgent AgentApproach(ms)Approach(ms)07008600.640.648600.20.282.7582.75Estimated TotalTime of Market3419.895.8Computingcommunication is performed using the old allocation,which causes the data to be transmitted more/less thanideal amount in each connection and to cause loss inthe user’s utility.4.2.ResultsTable1shows the time for each stage of the calculation.The,which is the time to transmit price from an Auctioneer to a QoS Client via network,is as large as0.86msec.On the other hand,in the mobile agent approach,there is almost no overhead because it can be done as an inter-process communication inside the same host.The time consumed by the calculation in an agent and an auctioneer, and respectively,are the same in both implementations.The time to send the allocation result to QoS Market via network,,is82.75msec in both implementation.Mobile agent approach requires the time to move agents in the network other than those shown in Table1,and the ,which is the mean time for a mobile agent to move from the QoS Client to the market server is about700msec.This,however,does not have much impact in the efﬁciency, since the move is performed only once in the lifetime of the agent and does not occur in each of the calculation cycle.The total time of a market calculation cycle is then estimated by applying these results to the equation1and2 in Section3.1.Assuming20,the time of one cycle in the static agent approach is208306483028334198 while that in the mobile agent approach is200064002839587From this result,we conclude that there is a large differ-ence in the efﬁciency of market calculation between static/ mobile agent approaches.According to the result of the second experiment,the average overhead is suppressed457.8msec,which means that the system achieves practically sufﬁcient efﬁciency.We believe superiority of the mobile agent approach to the static agent approach will not be changed in several years.Since the size of each message is small enough compared to the total bandwidth,the delay in the trans-mission of the messages are caused almost exclusively by the network latency.Thus,the performance will not be improved much even if the network technology advances, because such progress is usually in bandwidth rather than in latency.5.ConclusionThe protection of users’private preference and the efﬁ-cient calculation are both important in the market computing to allocate network quality of service most efﬁciently,based on users’preference.In this paper,we discussed the im-plementation of the market-based application QoS control system,which derives optimal resource allocation based on users’preference,from the viewpoint of efﬁciency,ﬂexibil-ity and privacy.To achieve these objectives,we proposed an approach based on mobile agent technology,and imple-mented the QoS Market system to validate the discussion.From the experimental results,we conclude as follows/ 1.The mobile agent approach achieves far more efﬁcientcalculation than the static agent approach,preserving the merits inﬂexibility and privacy.2.Our implementation succeeds in responding to thechange of user preference fast enough,with the delay of approximately450ms,and causes minimal commu-nication overheads.In this paper,we assumed an intranet of average size. Future research will cover a large-scale intranet,where the performance must be further improved because the delay by networks becomes more serious in the process of resource allocation.References[1]R.Braden,L.Zhang,B.Berson,S.Herzog,and S.Jamin,“Resource ReSerVation Protocol(RSVP)–Version1Functional Speciﬁcation,”Internet Request for Comments,RFC2205,1997.[2]S.H.Clearwater(Ed.),Market-Based Control:AParadigm for Distributed Resource Allocation,World Scientiﬁc,1996.[3]General Magic Odyssey WWW Page,/agents/odyssey.html,1996.[4]nge,D.T.Chang,“IBM Aglets Workbench–Programming Mobile Agents in Java,”IBM Corpora-tion White Paper,Sept.1996.[5]H.Nakanishi,C.Yoshida,T.Nishimura,and T.Ishida,“FreeWalk:Supporting Casual Meeting in a Net-work,”Proc.of CSCW’96,pp.308–314,1996.[6]Object space,Inc.,”ObjectSpace V oyager Techni-cal Overview,”/V oyager,1997.[7]T.Sander,C.F.Tschudin,“Protecting Mobile AgentsAgainst Malicious Hosts,”Givanni Vigna(Ed.),Mo-bile Agents and Security,LNCS1419,Springer,1998.[8]M.P.Wellman,“A Market-Oriented ProgrammingEnvironment and Its Application to Distributed Mul-ticommodity Flow Problems,”Journal of ArtiﬁcialIntelligence Research,V ol.1,pp.1–22,1993.[9]H.Yamaki,Y.Yamauchi and T.Ishida“Implementa-tion Issues on Market-Based QoS Control,”ICMAS-98,pp.357–364,1998.[10]H.Yamaki,M.P.Wellman and T.Ishida“A Market-Based Approach for Allocating QoS to MultimediaApplications,”ICMAS-96,pp.385–392,1996.8。

手机打车软件好还是不好英语作文

手机打车软件好还是不好英语作文Mobile taxi-hailing apps have become increasingly popular in recent years, offering a convenient and efficient way for people to book and pay for rides. However, the question of whether these apps are good or bad remains a topic of debate.On the one hand, mobile taxi-hailing apps offer numerous benefits to both drivers and passengers. For passengers, these apps provide a convenient way to book a ride without having to wait on the street for a taxi to pass by. They also offer the convenience of paying through the app, eliminating the need for cash or credit cards. In addition, these apps often provide information about the driver and the vehicle, giving passengers peace of mind about their safety.For drivers, mobile taxi-hailing apps offer a way to increase their income by providing them with a steady stream of customers. The apps also offer drivers the flexibility to choose their own working hours and locations, allowing them to work when and where it is most convenient for them.However, despite these benefits, there are also some drawbacks to mobile taxi-hailing apps. One of the main concerns is the issue of safety and security. While many of these apps havesafety features in place, such as driver background checks and GPS tracking, there have been reports of drivers and passengers being involved in accidents or even crimes while using these apps.Another issue is the impact that mobile taxi-hailing apps have on traditional taxi services. In many cities, traditional taxi drivers have seen a decrease in business as more people turn to mobile apps to book rides. This has led to tension between traditional taxi drivers and those working for ride-sharing companies.In conclusion, while mobile taxi-hailing apps offer numerous benefits in terms of convenience and efficiency, there are also drawbacks that need to be considered. It is important for both passengers and drivers to exercise caution and use these apps responsibly to ensure a safe and positive experience. Ultimately, whether mobile taxi-hailing apps are good or bad depends on how they are used and regulated.。

Take Content and Applications Mobile by Using Adobe GoLive CS2

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A museum tour guide in your pocket
After much planning, you are taking a vacation in Paris to see the work of your favorite artist—the famous E. Topliﬀe—at a special exhibition being held at the Louvre. You enter the museum, and while waiting in line, realize that according to the poster near the ticket desk, you’ve just missed that morning’s guided tour. The ticket agent conﬁrms this suspicion, gives you a ticket, and then asks if you have a browser-enabled mobile phone. Wondering why, you cautiously respond that you do have a browser-enabled mobile phone with you. The ticket agent says, “Wonderful, you are in luck! We have a new mobile virtual tour guide. Are you interested in purchasing access during your stay? It is 5 euros and can be used for seven days before the password expires.” After ensuring that you have a handsfree earpiece with you, the ticket agent asks for your phone number and then sends a bookmark to your device via SMS (Short Message Service). Once inside the Louvre, you open the SMS and open the browser by the bookmark. The bookmarked URL includes the site address of the tour guide as well as an argument that automatically signs you in with your user name and password. You select the E. Topliﬀe exhibition, and a map of the museum directs you to the room housing the exhibition. As you walk through the various rooms, you select the appropriate link for each one, and see yourself as a small dot on the ﬂoor plan shown on the screen. Once you arrive, you can open a second map that shows each work’s location in the exhibition. An additional Info menu item also takes you to a description of the exhibition and a brief overview of wood and mixed media, as well as the post-constructivism movement. As you move from painting to painting, you can use your phone to get more background information on each piece, as well as recommendations of similar works. Sometimes the information is a short video of an art historian; other times, it is a copy of a letter the artist wrote to his agent. When available, the information includes posters and other reproductions for sale in the gift shop. Selecting a favorite relief opens a virtual gift shop site that enables you to enter your credit card number and purchase a poster that is mailed to your home address. The exhibition is organized chronologically, but you are more interested in the theme of excavation in E. Topliﬀe’s work, and the personal tour guide application suggests various works that focus on this theme and marks their locations on the map. After a few hours of browsing, you ﬁnd that you are hungry. The main menu of the personal tour guide gives you a listing of nearby restaurants, with links to their menus. You leave the museum satisﬁed and feeling as if you have spent several hours with an art historian with a Ph.D. in the works of E. Topliﬀe.

2024-2025学年重庆市西南大学附属中学校高一上学期11月期中考试英语试题

2024-2025学年重庆市西南大学附属中学校高一上学期11月期中考试英语试题For Places RecommendedMuseum of Wu, Jiangsu provincePlaced on the bank o. the Grand Canal in Wuzhong district in Suzhou, Jiangsu province, the museum serves as a leading platform for the exhibition, research and the leaning of Wu culture and historical traditions of the Wu region. Wu culture is known for its distinct language, arts, customs and intellectual contributions, which have played a vital role in the development of Chinese civilization.Taiyuan Northern Qi Dynasty Mural Museum, Shanxi provinceThe museum features murals dating back 1, 400 years to the Northern Qi Dynasty in Taiyuan. It showcases the archaeological discoveries unearthed at the tomb of a high-profile official from the era. Ancient murals collected in Shanxi are on display in the museum, reflecting the accomplished artistry of ancient Chinese craftsmen.Luoyang Museum of Ancient Tombs, Henan provinceThe museum is located at Mangshan in the north suburb of Luoyang. It comprises a few complex buildings displaying the Han and Northern Wei dynasties’ architectural styles. Exhibition hal ls are located at the four comers and 25 ancient tombs are distributed to showcase the characteristics of typical tombs in Luoyang over 3, 000 years.Dingzhou Museum, Hebei provinceThe museum highlights the cultural and historical heritage of the ancient Zhongshan State, which existed during the Warring States Period in what is now Hebei. Visitors can also appreciate Dingzhou China, Buddhist culture and ancient writings at the museum which houses over 100, 000 cultural relics of significance.1. What do Museum of Wu and Dingzhou Museum have in common?A．They are located in the same province. B．They matter in cultural development.C．They exhibit numerous cultural relics. D．They lay great emphasis on culture.2. Which museum displays ancient architectural styles?A．Muscum of Wu, Jiangsu province.B．Taiyuan Northerm Qi Dynasty Mural Museum, Shanxi province.C．Luoyang Museum of Ancient Tombs, Henan province.D．Dingzhou Museum, Hebei province.3. Where can this article probably be found?A．In a travel brochure. B．In a book review.C．In a science fiction. D．In a news report.Zhai Yuliang becomes extra busy whenever the holidays are around the corner. The Beijinger, in his 60s, has just finished a pair of palace lanterns for a courtyard home in the capital.“The owner wants every part of them to be done in the old-fashioned way, so that they will fit perfectly with the grand style of their historical house,” says Zhai, who has practiced the craft for more than four decades. One of the most popular st yles, which is also Zhai’s favorite, is the double-layered octagonal (八角形的) palace lantern. It’s full of Chinese elements, and features dragon heads and many other specific patterns.However, he stresses the essential elements to be classified as palace lanterns — hand-painted scenes and Chinese knots (中国结) as decoration. Most importantly, they must be created using the specific techniques, which require over 100 steps.To make a palace lantern, a single craftsman has to do everything from the woodwork to the painting. “It takes months to make a palace lantern,” Zhai says. “It requires the skills of a woodworker, the knowledge of a mechanic, an appreciation of classical architecture, poetry, painting and an additional talent for mortise-and-tenon joints (榫卯) by hand before they can create the right carvings and layer combinations.Zhai has received many invitations from communities and institutes to show the charm of palace lanterns. He particularly enjoys hosting workshops where he teaches people to make lanterns themselves. He is enchanted to see the smiles of children and the expressions of adults when they complete their works under his guidance.He believes his lifelong devotion to this craft has been worthwhile. His lanterns can be seen in such locations as the Tian’anmen Square and many overseas sites that promote friendship with China.“Wherever you are, when you see a palace lantern, you know there’s a connection to China,” Zhai says.4. What is a must for a palace lantern?A．A dragon head in grand style. B．Application of over 100 techniques.C．Hand-painted scenes and Chinese knots. D．A double-layered octagonal pattern.5. Which of the following-best describes the process of makıng a palace lantern?A．Boring. B．Efficient. C．Creative. D．Demanding.6. The underlined word “enchanted” in Paragraph 5 is closest in meaning to ________ .A．Surprised. B．Confused. C．Delighted. D．Stressed.7. Which statement about palace lanterns may Zhai Yuliang agree with?A．They bring him fame and fortune.B．They act as a cultural link to China.C．They’ re well preserved in overseas locations.D．They connect him with many other craftsmen.A few days ago, I watched a video of myself talking in perfect Chinese. I’ve been studying the language on and off for only a few yea rs, and I’m far from fluent. But there I was, pronouncing each character just as a native speaker would. “My favorite food is sushi,” I said — wo zui xihuan de shiwu shi shousi.I’d created the video using software from a Los Angeles-based artificial-intelligence start-up called HeyGen. The technology, which only needs a single selfie and a script to generate deepfake videos of real people “saying” almost anything, is a testament (证明) to the advancements in AI language tools. This got me thinking about the declining interest in language learning with fewer students enrolling in foreign language courses and the decrease of English proficiency among young people in some places.AI translation, integrated into social media and messaging platforms, seems to be everywhere. Even language-learning apps are using AI-generated content in their marketing. However, language translation is an art rather than a science. Something enormous will be lost in exchange for that convenience. As Anne, a Chinese translator said, “Building a ladder between widely different languages, such as Chinese and English, is sometimes as difficult as a doctor building a bridge in a patient’s heart,”Language learning fosters cultural competency, a skill that AI cannot simply copy. Learning a different way to speak, read, and write helps people discover new ways to see the world. No machine can replace such a profoundly human experience. Deborah Cohn, a language professor, emphasizes that language learning is actually about understanding and connecting with different cultures; Instead of abandoning language courses in favor of AI, some educators advocate for emphasizing the intercultural aspects of language learning. Paula Krebs of the MLA points out that even with a “universal translator”, sometimes, the greater meaning of people’s utterance (言辞) remains a mystery.In essence, while AI language tools offer convenience, they lack the depth and cultural insight that comes from human language learning. The challenge and beauty of learning a language are in understanding the cultural tapestry (织锦) that weaves through words, something AI has yet to achieve.8. Why does the author give the example in paragraph 1?A．To promote the language software.B．To show off his Chinese language skills.C．To prove learning a language is a wasted effort.D．To encourage critical thinking about AI language tools.9. What can we learn from paragraph 3?A．AI translation deserves more attention.B．Language apps play a key role in marketing.C．Language translation is far beyond technology.D．Learning a different language is an uphill battle.10. What is the key benefit of learning a language according to the passage?A．Better digital literacy.B．Improved translation skills.C．Deeper cultural confidence.D．Effective intercultural interaction.11. What does the author imply in the last paragraph?A．AI language tools offer convenience.B．AI facilitates language learning in terms of culture.C．AI is far from perfect in helping language understanding.D．AI has achieved success in the development of language learning tools.For many, travel isn’t just about the destination —it’s about making the most of the journey. However, for a lot of people, the journey is often ruined by an uncomfortable experience often accompanied by vomiting, known as motion sickness. If you’ve ever felt the unwelcome urge to vomit while reading or using your device in a moving vehicle, you’re not alone. Recognizing this common issue, Apple has stepped up to offer a revolutionary solution; the Vehicle Motion Cues feature for iPhones and iPads.Motion sickness occurs when there is a disconnect between what your eyes see and what your body feels. When you’re in a moving vehicle, your body senses motion through its vestibular system (t he inner ear), but if your eyes are focused on a still screen that doesn’t reflect this movement, the brain receives mixed signals. This sensory conflict can lead to dizziness, nausea, and overall discomfort - symptoms all too familiar to motion sickness sufferers.Apple’s new Vehicle Motion Cues feature is designed to bridge this gap and bring relief to those likely to experience motion sickness. This revolutionary feature works by displaying animated dots, around the edges of your screen, which move at the same time and speed as the motion of your vehicle. These moving cues help keep the motion your body feels in line with what your eyes see, effectively reducing the sensory mismatch that causes motion sickness.The magic lies in the simplicity and effectiveness. The animated dots move in consistency with the vehicle’s motion, providing a visual representation of the movement your body is experiencing. By matching the visual input with the physical sensations of motion, your brain is less likely to experience the confusion that leads to sickness.Early reports and user feedback indicate that Vehicle Motion Cues is receiving high praise for its effectiveness. So next time you embark on a journey, whether short or long, remember that Apple’sgot your back — or rather, your brain - helping you make the most of every mile with ease and comfort.12. Which type of people can be interested in Vehicle Motion Cues?A．Frequent travelers. B．Book lovers.C．Vehicle operators. D．Sport scientists.13. What is paragraph 2 mainly about?A．The principle of Apple’s new design.B．The cause of motion sickness.C．The functions of Apples new design.D．The symptoms of motion sickness.14. By displaying animated dots around the screen, Applet Vehicle Motion Cues is able to_____.A．ease sensory conflicts in the brainB．tell the mismatched physical sensationsC．balance the movement of our eyes and bodyD．increase the effectiveness of vehicle motion15. Which can be the best title of the passage?A．Make the Most of Your Journey： Apple Bridges the. GapB．Find the Magic of a Moving Vehicle: Apple’s Got! Your BackC．Enjoy Your Reading: Apple Offers a Revolutionary SolutionD．Say Goodbye to Motion Sickness: Apple Introduces Its New DesignDo you like cilantro(香菜)? Cilantro is a common food that people tend to either adore or abuse. 16 But the reasons behind what you like and don’t like are not always so straightforward.17 Your sense of smell allows you to distinguish between something like strawberry and cherry. Scientists looked at olfactory (receptors and discovered that individuals with a certain gene. OR6A2, are more sensitive to smelling cilantro. That, in turn, affects how people sense its flavor. 18 When you’re open to these foods, you learn to like what you eat. Eve n people who hate cilantro may be able to learn to at least tolerate it, if not like it.Culture plays a big role in what you like, too. Food preferences vary across cultures. When it comes down to food preferences in different parts of the world, it has a lot to do with what’s available and considered a food staple (主食). 19 But there will always be exceptions-a Greek person who can’t stand olives or a Dutch person who hates cheese.While preferences can be formed after a few attempts, negative experiences with foods, especially when you’re young, can have a lasting effect. 20 Jasmine Robinson, 29, from Athens, shared her story about olives. When she was young, another child, who wouldn’t let her have a turn on a swing, made fun of her while eating olives from a jar and being mean. She later tried olives as an adult but failed.Two years ago, my friend and I were at college. With his birthday quickly________ , he came to me with an unusual________: instead of receiving presents. he wanted to do some acts of kindness.I was________with such an idea.________ instead of taking for the birthday was really different. I asked him how he could come up with such a ________ idea. He told me about a TED talk he had watched on generosity, which had inspired him. So we started to ________ creative things we could do.Our university employed some security guards to protect its students. They have to work________ , keeping watch on every corner throughout the university. For the most part it’s a ________ job as most people grow accustomed to seeing the guards all around and at last ________ notice their presence, let alone acknowledging their efforts. How could we show them our appreciation?We decided to make a large pot of hot________. We hired a car and asked the driver to take us around the campus where we knew the________would be and we poured them each a cup of hot chocolate. The driver was initially a bit ________ about the entire plan but after a while he was helping us spot the guards and our lively spirit had ________to him as well. We met withmany________ and appreciative words. It was amazing to see how a. small act or even an intention of generosity can ________ everyone’s spirit.21.A．ending B．passing C．advancing D．approaching 22.A．order B．request C．problem D．story23.A．struck B．disappointed C．comfortable D．bored24.A．Refusing B．Earning C．Giving D．Donating25.A．complex B．novel C．familiar D．traditional26.A．plan out B．take over C．watch for D．hold back27.A．step by step B．around the clock C．more or less D．now and then28.A．thankless B．careless C．reasonable D．respectable29.A．hardly B．obviously C．naturally D．generally30.A．tea B．milk C．soup D．chocolate31.A．workers B．students C．guards D．drivers32.A．grateful B．doubtful C．annoyed D．excited33.A．spread B．moved C．happened D．returned34.A．friends B．difficulties C．greetings D．smiles35.A．pull B．turn C．lift D．break36. Students are usually required to choose their preferred subjects at high school — a practice that allows them to stay ______(compete)in the college entrance exam. (所给词的适当形式填空)37. It is the great encouragement and selfless support from his mother ________ have carried him through the toughest times. (用适当的词填空)38. Travelers are recommended _____(check) the weather forecast before starting their journey. (所给词的适当形式填空)39. The fans _______ (pack) into the newly constructed stadium created an exciting atmosphere that could be felt miles away. (所给词的适当形式填空)40. That grand bridge, _______which the latest construction method has been applied, is now welcoming praises from citizens. (用适当的词填空)41. Nearly all students of that university expressed their _______ (admire) for the rich knowledge and great wisdom the scholar showed in the lecture. (所给词的适当形式填空)42. As the technology has advanced, household computers have gotten much _______ (powerful) processors with thinner and larger screens. (所给词的适当形式填空)43. Thinking about something confusing, he gazed at the horizon, with his eyes ________(narrow). (所给词的适当形式填空)44. Usually, British people make it natural to start a day with _______(formal) talks, such as discussing the weather. (所给词的适当形式填空)45. The Amphicar is_____unique means of transport that can smoothly travel between waterways and land. (用适当的词填空)46. It’s impolite to comment ______ others’ decisions if you don’t know the sufferings and adversity they encounter. (用适当的词填空)47. ______ (recognize) in public at the grocery store was an unexpected surprise for the former athlete. (所给词的适当形式填空)48. As we all know, English is the _______ (office) language of more than 70 countries including British and Australia. (所给词的适当形式填空)49. Present at the opening ceremony ________ the leaders of the two countries, who, afterwards, planted a tree together on the occasion. (用适当的词填空)50. The head teacher made a request that a meeting _______ (schedule) to arrange for the upcoming anniversary of the school’s founding day. (所给词的适当形式填空)阅读下面短文，在空白处填入1个适当的单词或括号内单词的正确形式。

2024年英语a级考试卷

2024年英语a级考试卷Part I. Listening Comprehension (20%)Section A: Short Conversations (10%)Directions: In this section, you will hear 5 short conversations. At the end of each conversation, a question will be asked about what was said. Both the conversation and the question will be spoken only once. After each question, there will be a pause. During the pause, you must read the four choices marked A), B), C) and D), and decide which is the best answer.1. M: I'm so tired. I've been working on this project all day.W: Why don't you take a break? You've been at it for hours.Q: What does the woman suggest the man do?A) Keep working.B) Finish the project quickly.C) Take a break.D) Start a new project.2. W: Do you like this dress? I'm not sure if it suits me.M: It looks great on you. The color really brings out your eyes.Q: What does the man think of the dress?A) It doesn't look good.B) The color is not nice.C) It suits the woman well.D) It is too expensive.3. M: How much is this book?W: It's 20. But if you have a membership card, you can get a 20% discount.Q: How much will the man pay if he has a membership card?A) 16.B) 18.C) 20.D) 24.4. W: Are you going to the concert tonight?M: I'd love to, but I have to study for my exam tomorrow.Q: Why isn't the man going to the concert?A) He doesn't like the concert.B) He has no money.C) He has to study.D) He is sick.5. M: What time does the library close today?W: It usually closes at 9 p.m., but on Fridays it closes an hour earlier.Q: What time does the library close on Fridays?A) 8 p.m.B) 9 p.m.C) 10 p.m.D) 7 p.m.Section B: Long Conversations (5%)Directions: In this section, you will hear 2 long conversations. After each conversation, you will be asked some questions. The conversations will be read twice. Listen carefully and answer the questions.Conversation 1M: Hi, Jane. How was your weekend?W: It was great. I went to the beach with my friends.M: That sounds like fun. What did you do there?W: We swam, sunbathed, and had a picnic.M: Did you take any pictures?W: Of course. I took a lot of beautiful pictures.Questions:6. Where did Jane go on the weekend?A) To the mountains.B) To the park.C) To the beach.D) To the city center.7. What did Jane do at the beach?A) She only swam.B) She swam, sunbathed and had a picnic.C) She just sunbathed.D) She played volleyball.Conversation 2W: Good morning, sir. Can I help you?M: Yes, I'm looking for a gift for my daughter. She likes reading.W: Well, we have a lot of books here. What kind of books does she like?M: She likes novels, especially those about adventure.W: Then I recommend this one. It's a very popular adventure novel.M: Thank you. How much is it?W: It's 15.Questions:8. Who is the man buying a gift for?A) His wife.B) His daughter.C) His mother.D) His sister.9. What kind of books does the man's daughter like?A) Poetry.B) Science fiction.C) Novels about adventure.D) History books.10. How much is the book?A) 10.B) 15.C) 20.D) 25.Section C: Passages (5%)Directions: In this section, you will hear 1 passage. The passage will be read twice. Listen carefully and answer the questions.The Internet has become an important part of our daily lives. We can use it to get information, communicate with others, and do shopping. However, we should also be careful when using the Internet. There are some risks, such as identity theft and virus attacks. To protect ourselves, we should use strong passwords, not click on suspicious links, and install antivirus software.Questions:11. What can we use the Internet for?A) Only getting information.B) Getting information, communicating and shopping.C) Just shopping.D) Communicating and playing games.12. What are the risks of using the Internet?A) Identity theft and virus attacks.B) Only virus attacks.C) Losing money.D) Meeting bad people.13. How can we protect ourselves when using the Internet?A) Use weak passwords.B) Click on all links.C) Use strong passwords, not click on suspicious links and install antivirus software.D) Don't use antivirus software.Part II. Vocabulary and Structure (30%)Section A: Multiple Choice (20%)Directions: There are 20 incomplete sentences in this section. For each sentence there are four choices marked A), B), C) and D). Choose the one answer that best completes the sentence.14. She is very ______ in music and can play several instruments.A) interested.B) interesting.C) bored.D) boring.15. I can't find my keys. I ______ them in the office.A) must leave.B) must have left.C) should leave.D) should have left.16. The new bridge ______ next year will be the longest in the city.A) to be built.B) built.C) being built.D) having been built.17. If it ______ tomorrow, we will go for a picnic.A) doesn't rain.B) won't rain.C) not rain.D) didn't rain.18. He has made great ______ in his English study in the past few months.A) progress.B) progresses.C) a progress.D) the progress.19. I don't like this shirt. Can you show me ______ one?A) another.B) other.C) the other.D) others.20. She is so busy that she has ______ time for hobbies.A) little.B) a little.C) few.D) a few.21. The movie was so ______ that many people left the theater early.A) bored.B) boring.C) excited.D) exciting.22. He ______ his homework when his mother came home.A) was doing.B) is doing.C) does.D) did.23. We are looking forward to ______ from you soon.A) hear.B) hearing.C) be heard.D) have heard.24. There are ______ students in our class, twenty boys and twenty - five girls.A) forty - five.B) forty - four.C) forty - three.D) forty - six.25. She speaks English as ______ as her brother.A) good.B) well.C) better.D) best.26. The book ______ I bought yesterday is very interesting.A) who?B) which.C) where?D) when?27. I'm sorry I'm late. I was ______ in traffic.A) held up.B) held on.C) held out.D) held back.28. My parents ______ me to become a doctor when I was a child.A) hoped.B) wanted.C) expected.D) wished.29. He is old enough to ______ himself.A) look after.B) look for.C) look up.D) look into.30. ______ of the two boys is taller.A) All.B) Both.C) None.D) Neither.31. The teacher told us ______ noise in class.A) not make.B) not to make.C) don't make.D) to not make.32. She ______ a lot of money on clothes every month.A) spends.B) costs.C) takes.D) pays.33. I have ______ been to Paris. I really want to go there.A) never.B) ever.C) already.D) just.Section B: Fill in the Blanks (10%)Directions: There are 10 blanks in the following passage. For each blank there are four choices marked A), B), C) and D). Choose the best one to fill in each blank.Most people like traveling. Some people like to travel by plane, while others prefer to travel by train. Traveling by train has many advantages. First of all, it is much _34_ (cheaper/safer/faster/more expensive) than traveling by plane. You can save a lot of money. Secondly, you can enjoy the beautiful _35_ (scenery/people/cities/airports) along the way. You can see mountains, rivers, and fields. Thirdly, traveling by train is more _36_ (comfortable/uncomfortable/dangerous/boring). You can walk around, stretch your legs, and even have a meal in the dining car.However, traveling by train also has some _37_(advantages/disadvantages/benefits/pleasures). For example, it usually takes a longer time to reach your destination. And sometimes the trains can be very _38_ (crowded/empty/quiet/clean), especially during the peak travel season.In conclusion, whether you choose to travel by train or by plane depends on your _39_ (money/time/needs/health) and preferences. If you want to save money and enjoy the journey, traveling by train is a good _40_ (idea/way/choice/plan). But if you are in a hurry and don't mind spending more money, traveling by plane may be a better _41_(option/answer/solution/result).When you are traveling, it is important to _42_(prepare/forget/ignore/neglect) well in advance. You should book your tickets early, pack your bags properly, and make sure you have all the necessary _43_ (things/items/objects/stuff) with you.Part III. Reading Comprehension (30%)Section A: Multiple - choice Questions (20%)Directions: There are 2 passages in this section. Each passage is followed by some questions or unfinished statements. For each of them there are four choices marked A), B), C) and D). You should decide on the best choice.Passage 1.The mobile phone has become an essential part of our lives. We use it to communicate with others, get information, and even do business. Mobile phones are getting more and more advanced. They have larger screens, better cameras, and faster processors.However, there are also some problems associated with mobile phones. One problem is that people are spending too much time on their mobile phones. This can lead to a lack of face - to - face communication andsocial isolation. Another problem is that mobile phones can be a distraction, especially when people are driving or studying.To solve these problems, we should use mobile phones in moderation. We should also set aside some time for face - to - face communication and other activities.44. What can we use mobile phones for?A) Only communicating.B) Communicating, getting information and doing business.C) Just getting information.D) Doing business and playing games.45. What are the problems of mobile phones?A) People spend too much time on them and they can be a distraction.B) They are too expensive.C) They have small screens.D) They are difficult to use.46. How can we solve the problems of mobile phones?A) Use them all the time.B) Use them in moderation and set aside time for other activities.C) Stop using them.D) Buy new ones.Passage 2.In recent years, more and more people are interested in learning a second language. There are many reasons for this. For one thing, learning a second language can open up new job opportunities. For another, it can help people understand different cultures.There are many ways to learn a second language. One way is to take language classes at a school or language center. Another way is to use language learning apps. These apps can be very convenient as you can learn at your own pace.However, learning a second language is not easy. It requires a lot of time and effort. You need to practice speaking, listening, reading and writing regularly.47. Why are more people interested in learning a second language?A) Because it is easy.B) Because it can open up new job opportunities and help understand different cultures.C) Because it is fashionable.D) Because they have nothing else to do.48. What are the ways to learn a second language?A) Only take language classes.B) Take language classes or use language learning apps.C) Only use language learning apps.D) Read books.49. What is required to learn a second language?A) A lot of time and effort, and regular practice of all skills.B) Only a little time.C) No effort.D) Just listening practice.Section B: True or False (10%)Directions: Read the following statements. Write "T" if the statementis True and "F" if the statement is False.50. Mobile phones have no negative effects. (F)51. Learning a second language is very easy. (F)52. Traveling by train is always faster than traveling by plane. (F)53. If you have a membership card, you can always get a discount when buying things. (F)54. People should use strong passwords to protect themselves when using the Internet. (T)Part IV. Writing (20%)Section A: Translation (10%)Directions: Translate the following sentences into English.1. 他昨天晚上熬夜看足球比赛了。

Mobile agent interaction in heterogeneous environment

Mobile Agent Interaction in Heterogeneous EnvironmentsPeter D¨o mel Anselm Lingnau Oswald DrobnikE-Mail:doemel,lingnau,drobnik@rmatik.uni-frankfurt.deDept.of Computer ScienceJ.W.Goethe–Universit¨a t Frankfurt/MainAbstract An open problem in mobile agent research is the interaction between agents in dif-ferent‘worlds’.In this paper,we survey various approaches to agent interaction and discuss the interoperation between Telescript and agents through the use of the Hypertext Transfer Protocol(HTTP)and the shared information space provided by.Keywords:mobile agents,interaction,HTTP,Telescript,,KQML1IntroductionMobile agents—programs that can move around in a computer network on behalf of their users—are attracting more and more attention.Various research efforts take place in this area,for example TACOMA(Tromsøand Cornell,[1]),Ara(Univer-sit¨a t Kaiserslautern,[2]),Mole(Universit¨a t Stuttgart,[3]),and the projects InAMoS and InA V AS of the DAI Laboratory/TU Berlin[4].Several interpreted languages are suitable for the programming of mobile code.Among them Java[5],Tcl(with ex-tensions like or AgentTcl)[6],Python[7],and Perl[8].Commercially available systems include Telescript[9]and CyberAgents[10].Operating systems like Inferno[11]are also likely to support mobile agents in the future,because much of the necessary infrastructure is already provided.With so many infrastructures available,an obvious question to ask is how one could try to make different kinds of mobile agents interoperate.Since it is unlikely that a common standard for‘doing’mobile agents will emerge anytime soon,it seems worthwhile to examine how different agent systems handle interaction‘inter-nally’,and how one might establish‘interfaces’that let information cross the border between different mobile agent‘worlds’.To begin with,a coarse distinction may be drawn between direct and indirect in-teraction.With direct interaction,agents can directly call code within other agents—this is usually approached from an object-oriented point of view,with agents adver-tising interfaces,i e.,sets of methods that other agents may access.For example, this style of interaction is used within Telescript.Indirect interaction means that the agent system mediates interaction between agents without letting them contact one another directly—either by having agents send messages to others which are for-warded by the agent infrastructure,or by interposing an information space whereagents can deposit items.These approaches are surveyed more closely in theﬁrst part of the paper.A protocol which is widely used,albeit not only in the context of mobile agents, is the Hypertext Transport Protocol(HTTP,[12]).This is the standard protocol for information access on the World-Wide Web[13];since many agent systems allow agents to retrieve WWW resources or even to provide such resources them-selves,it turns out that the necessary mechanisms for HTTP access are already in place for many mobile agent systems.The second part of the paper examines two such systems—Telescript and the authors’own(short for FrankFurt Mobile Agent INfrastructure)—in more detail,and in theﬁnal part of the paper we argue that HTTP is a useful protocol for enabling information exchange and cooperation across different agent‘worlds’.This is exempliﬁed by an experiment linking Tele-script and agents in the context of an electronic marketplace.2Mobile Agent Interaction:An Overview2.1Direct Agent InteractionIn some of the systems,agents are implemented as active objects(objects which represent running threads or processes).The natural way for an agent in such an environment to interact with another agent is by simply calling that agent’s methods. To be able to do this,agents need references to one another.By carefully controlling which agent obtains what references to other agents,the privacy of agents can be assured.To give an example of a system with very tightly coupled object-oriented agent interaction,we look at the Telescript platform.However,it is imaginable that Java-based mobile agent platforms could use a similar way for agents to communicate, because the basic language concepts of Java and Telescript are very similar.Telescript is a proprietary programming language developed at General Magic [14].Its goal is to make it possible to program computer networks like Postscript al-lows to program printers.Mobile agents seem to be ideally suited to provide offline support for small portable devices like PDA’s(Personal Digital Assistants),PICs (Personal Intelligent Communicators)and computerized cellular phones.Telescript can be brieﬂy characterized like this:There are three simple concepts to the language:agents,places and‘go’.Agents‘go’to places,where they interact with other agents to get work done on a user’s behalf.Agents are,in fact,mobile programs capable of transporting themselves between places in a Telescript net-work.The language is implemented through a multitasking interpreter,called the Telescript engine.The use of direct method calls is one of the central agent interaction mechanisms in Telescript.In order to be able to call another agent’s methods an agent mustﬁrst meet the other agent,which is only possible if both agents are visiting the same place.A meeting is initiated by executing the operation of this place,which returns a reference to the agent to be met.This operation takes a petition object asits argument.An agent can only successfully meet another agent if it possesses a valid petition.When an agent calls another agent’s methods,it usually passes some objects as arguments and often receives one or more objects as the result of the method calls. But what happens when two agents have references to the same objects and one agent decides to go to another place(which might be located on another machine)? This conﬂict is resolved in Telescript by the object ownership concept.The default behaviour is that an object is owned by the thread under whose control it was cre-ated.This means that when an agent creates an object,it owns that object.Whenever an agent migrates itself to another place,it takes with it all the objects it owns.To do this,the engine collects all the objects owned by this agent and voids the refer-ences other agents or the place may have to these objects.In case an agent does not recognize that its partner has left and tries to use the reference an exception will be thrown.Other ways for agents to interact asynchronously in Telescript are through thread synchronization mechanisms like events and resource-protection.A system which extends the direct interaction paradigm is the Common Object Request Broker Architecture(CORBA,[15]).This architecture allows the remote invocation of objects in a distributed environment via an RPC mechanism.An object request broker(ORB)allows the interaction of objects written in different languages but not the mobility of code.2.2Indirect InteractionThe Infrastructure Many mobile-agent systems(e.g.,Telescript)can be considered closed and proprietary:They prescribe a given language for agent de-velopment and use custom protocols for agent mobility and interaction.In contrast, the infrastructure[16]developed by the authors is not tied to any particu-lar programming language and effects agent interaction and movement through the Hypertext Transport Protocol(HTTP),an Internet standard[12].Agents are con-trolled by agent servers(typically one per host)which help agents communicate among themselves and with users as well as move between ers can take advantage of common World-Wide Web browsers to submit agents to the system as well as to interact with the agents or retrieve results;the agent servers function as HTTP servers in order to present information to users via pages and forms using the Hypertext Markup Language(HTML)[17].With a language-independent system like,a direct-interaction approach such as the one discussed in the previous section is not feasible,since differences in the languages concerned will preclude the direct invocation of one agent’s meth-ods by another.(This could be worked around to a certain extent by concepts like CORBA.)Therefore,the abstraction used in is similar to that put forward in LINDA[18]:Each agent server maintains a local information space that agents can use to publish interesting pieces of information for perusal and manipulation by other agents.Items in the information space are identiﬁed through unique keys andendowed with a set of access rights detailing which agents are allowed what opera-tions.The basic operations deﬁned on information space items include put(insert an item),get(read an item)and dget(‘destructive get’—read and remove an item).Allthese operations are performed atomically;their implementation is based on HTTP with several(small)extensions1.The information space is also used by the agentserver to publish interesting data.This lets agentsﬁnd out about other agents as well as the services offered by the agent infrastructure on the host in question.—It is possible to develop more reﬁned interaction schemes such as RPC,broadcast,blackboard systems,...based on these basic operations(see[19]).While agents currently use custom protocols to interoperate—they canﬁnd out what other agents support by looking at the agent list published by the server—it would also be possi-ble to implement KQML-based agent interaction(see next section)via the informa-tion space.KQML and its Infrastructure KQML,the Knowledge Query and Manipulation Language[20],is a language and protocol for exchanging information.Its purposeis to facilitate the cooperation of very different intelligent agents,by providing a framework to support them in identifying,connecting with andﬁnally exchanging information with each other.It does so by deﬁning an extensible set of message types(performatives or speech acts)and their meanings.KQML consists of a communi-cation layer(dealing with the identity and addresses of agents),a message layer (deﬁning the performatives)and a content layer(dealing with the actual content);itdoes not attempt to standardize the format of the information being exchanged,nor does it specify exactly how this information is to be moved.Figure1shows the conceptual architecture used in the KQML speciﬁcation by the External Interfaces Group,a working group of the ARPA Knowledge Sharing Effort.This architecture serves as another example for indirect agent interaction,whereas the language KQML itself can well be used in other architectures(like )as an abstraction for describing and encapsulating agent operation invo-cations.In contrast to direct object-oriented agent interaction,it does not requiremobility of the interacting agents,although agent mobility could improve the efﬁ-ciency of the system.Each software agent has a separate router process(K-router),which handles allKQML messages sent and received by its agent.When a K-router is unable toﬁnd the recipient for a message,it consults facilitator agents which provide network services like content-based routing,brokering between suppliers and consumers, recruiting suppliers to deal directly with consumers,and smart multicasting.The KRIL(KQML Router Interface Library)is an API to the external K-router process which is embedded in the agent application itself.Two common KRIL operations are and for submission and re-ception of KQML messages.KQML represents a framework for agent communication rather than something which is directly useful.It can serve as a conceptual middleware between agents byKRILKQML andpropriatary messagesK-RouterAgentNetworkKQML messages only KRIL K-Router Facilitator Agent KRIL K-Router Agent Figure1.Conceptual KQML infrastructureintroducing a common set of operations (the performatives)that various agents can support.KQML by itself cannot guarantee that the agents will actually be able to do something useful with the information they exchange.3Interfacing Mobile Agents and the Web3.1Telescript Agents and the WebThe Telescript runtime environment was originally designed for the use in big net-work servers,operated by service providers.A set of tools [21]allows users to create,control and interact with Telescript agents via ordinary Web browsers.More-over,these tools enable Telescript agents to access the WWW and support them in using its services by ﬁlling out forms and parsing the resulting HTML pages.Using these tools,Agents may be used to build value added Web services.Agents can,e.g.,be used to search information in the Internet,monitor changes of Web pages or build meta services 2.The mobility of agents can help to do this more efﬁciently by avoiding network trafﬁc whenever great amounts of data have to be processed.In ﬁgure 2we give a rough overview of how a Telescript engine is connected to the WWW via the Telescript Web Tools resp.TabrizWare .Users (and administrators)can create and control their personal agents by select-ing special URLs in their Web browsers.Another way to communicate is by ﬁlling out HTML forms generated by their agents.Such a URL may,e.g.,look like:The browser requests the resource bound to this URL from an ordinary Web server running on host using port .This server was conﬁgured such,that thepart of the URL causes it to perfom HTTP-based authentication.By requir-ing users to log in,the system can bind identities of agents to identities of users.The URL part refers to a CGI process,,which takes all theFigure2.Telescript Web Tools(Tabriz)CGI variables provided by the Web server and the user and creates a Telescript data-structure out of it.Then connects to the Telescript engine(represented bya cloud)where the rest of the URL is processed.Because the user has not created a earlier in our example, by default such an agent will be created by the place,which also con-tains a registry of services(‘R’inﬁgure2)and information about registered users (‘U’inﬁgure2).From this service registry the agent gets the addresses(repre-sented by objects)of two places offering CDs as well as a ticket to the .First the agent‘goes’to the where it makes a note(enters its URL)in the user’s personal HTML pages,so that the user can con-tact it,if necessary.The part of the URL invokes the agent’s method.Because the agent owns the associative array(created by the pro-cess)which contains all the necessary CGI variables,it knows that the user is in-terested in CDs with the title Equinoxe.First it visits the where it s the shop’s service agent and asks it about availability and price of CD’s with the title Equinoxe.This service agent,however,is only a front-end to a nor-mal WWW CD store service.With the help of a Web access API(‘W’inﬁgure2) it communicates with the external process,which uses the HTTP client library[22]to access a HTML form based WWW CD store service.The service agent of the simplyﬁlls out the appropriate forms and parses the resulting Web pages.From this information it generates the result to the ’s question.After it got itsﬁrst result,‘goes’to thewhich is provided by another Telescript engine on another network server.This engine may also be connected to the Web using the Telescript Web Tools,but it may as well be a standalone Telescript engine,offering pure Telescript services.In our example the service agent of has its own data repository inside the place and no need to access other services in order to operate the‘shop’.However, this agent could as well be an interface agent to an external database system.This little electronic marketplace scenario covered all the important parts of the Telescript Web Tools,which consist not only of the external processes,theplace and the so-called mix-in interfaces’R’,‘U’and‘W’,but also of an HTML API which on one hand allows agents to create HTML documents as a hierarchy of Telescript objects which are automatically rendered to HTML,and on the other hand is able to parse HTML code and generate the corresponding hierarchy of Telescript objects.A library of superclasses gives agents,e.g.,the ability to interactively‘talk’to users via HTML forms.These superclasses also provide all of the necessary infra-structure to hide HTTP-speciﬁc issues from agents and places.3.2Controlling Agents inAs explained in section2.2,the infrastructure is completely based on HTTP. In principle,a user can create an agent simply by submitting an appropriately for-mattedﬁle containing its source code and initial state through a WWW browser(or even a TELNET connection).For convenience,this is usually done via an auxil-iary‘launching’program.As a matter of fact,this program can be invoked from the Web;this makes it straightforward for information providers to add mobile agents to their offerings.Another advantage of this approach is that agents can be conve-niently conﬁgured through a HTML form which is constructed dynamically by the launching software from a speciﬁcation embedded within the agent’s source code (seeﬁg.3).Once an agent has been submitted,the launching software returns to the user a URL which can be used for subsequent queries about the agent,to fetch its results or to kill or revoke the agent.This URL leads to a HTML page maintained by the agent server the agent was initially submitted to(its home server);the agent servers keep track of agents moving among one another in order to keep the information about an agent’s whereabouts up-to-date.HTTP‘redirect’messages are used to point an in-quiring user’s WWW browser to the correct server.Agents,in turn,can send partial results to their home servers to be made available to users as HTML pages.This focus on HTTP for agent mobility and control allows users to view mobile agents as a seamless extension to their usual World-Wide Web environment.They do not have to get familiar with yet another user interface in order to take advantage of mobile agents.In,agents can also interact with other resources on the World-Wide Web.In order to effect a separation of concerns and to keep generic mobile agents operating on a basis of least-privilege,WWW access would usually be through aFigure3.Agent conﬁguration in:Speciﬁcation and presentationtrusted stationary agent accepting URL requests via the information space,possibly vetting these to avoid costly requests(e.g.,non-local or international),and return-ing the data addressed by the URL in question to the requesting agent,again via the information space.While there is no problem in principle with allowing every mo-bile agent to access the WWW at will,this approach lets the maintainer of an agent server retain maximum control over the site’s security and resource usage.does not offer in-built methods for parsing and generating HTML by agents;it is be-lieved that this can be safely left to the relevant support available in the various agent implementation languages.Tcl and Perl,for example,contain sophisticated exten-sions for HTML management;it appears more worthwhile to offer safe methods of accessing these rather than re-invent the wheel.4Interaction Between Agent Systems Through HTTP4.1Direct Agent InteractionIf users can control and interact with agents through WWW browsers by using an HTTP-based remote control mechanism(as in section3.1)and agents can act on behalf of their users by issuing HTTP requests,it follows that agents can interact with one another using HTTP.In the case of direct interaction,HTTP represents a simple RPC mechanism.Every URL corresponds to a remote method invocation; arguments can be wrapped up in the URL,and results are returned just like WWW pages.Thus,agents have the option to decide whether they want to‘’to another agent,or whether it is cheaper or faster to remotely invoke its methods.This decision is a trade-off between the costs of agent migration(depending on its code and data size and the costs for encryption and encoding of the agent)and the amount of datato be exchanged between service and agent(plus the RPC-overhead).Figure4.Telescript agents access informationspace via HTTP Figure5.Access form generated by a Telescript agentAs already mentioned in section 2.1,CORBA could be considered for language independent remote interaction between agents.But although CORBA allows pro-grams written in different languages to interact,usually different platform/language-dependant APIs are used (e.g.DSOM for IBM UNIX workstations and DCOM /ActiveX for environments based on Microsoft Windows).This does not represent a problem for non-mobile distributed software,but for mobile agents this is more of an issue because the CORBA libraries needed for the remote method invocations may differ from server to server.It could be necessary to have the agent platform provide some additional middleware as a common agent CORBA API.This ‘glue’code would likely be language-dependant as well as platform dependant.More-over,the runtime environment needed by CORBA-based applications is relatively heavy-weight and would require service providers to buy and run CORBA support software,whereas HTTP is,by comparison,such a lightweight protocol that every agent can easily carry its own protocol implementation.Also,there is no need to de-ﬁne and compile CORBA IDL speciﬁcations in order to remotely invoke methods offered by other agents or services.It is sufﬁcient to create simple URL strings con-taining the parameters.A more practical reason why we decided to experiment with the HTTP approach is that currently CORBA support by online service providers is not very common,but most services already are HTTP-based.Another simple example of HTTP usage,this time for agent/user interaction,is shown in ﬁgure 5.The HTML form was generated by a Telescript agent which takes the input from the user to access the information space and reads the value stored by the .Telescript agents may use the existing mix-in class to issue HTTP requests.This mix-in also uses a proprietary protocol to communicate withthe externalprocess which,e.g.,translates Telescript objects into C++ob-jects.This interaction can be considered similar to the KRIL/K-Router connection mentioned in section2.2.In this case,the mix-in corresponds to the KRIL and the target of the HTTP requests—e.g.,an information space—to the set of interconnected K-Routers.Furthermore,as we have seen in section3.1,it is also straightforward to con-struct an HTTP interface that will accept requests from an outside source and trans-late them into the appropriate native calls.Therefore,HTTP can play the role of a ‘common denominator’for communication between many different platforms.4.2Indirect Agent InteractionThe agent servers in the infrastructure communicate via HTTP.Their HTTP interface also allows authenticated access to their information spaces from outside. Not only does this enable management tools to connect to agent servers,e.g.,to dis-play and edit the content of the information space,but it also provides a simple way for other agent systems to read,write and remove data items with ease.Figure4 shows how,e.g.,Telescript agents may interact with agents by exchanging data via the information space.Other systems could be connected in the same fash-ion.(Actually,native agents use a compressed protocol based on HTTP to interact with the agent servers and to access the information space.This saves overhead and allows for more advanced features–native agents can,e.g.,re-quest to be asynchronously notiﬁed by the information space,whenever a certain data item has changed.This does not detract from the general accessibility of the information space through the usual HTTP operations.)Table1shows some examples for the protocol data exchanged with an agent server to communicate to the information space.The example reads the server’s port number(made available by the server itself in).The ex-ample creates a new data item which is owned by the agent.The example reads and removes the entry.Figure6gives a few examples of how an agent would interact remotely with a Telescript agent using the information space.Of course,two Telescript agents could also interact this way,which might be useful to save the overhead of two and one operation when only a few bytes of information have to be exchanged.In the‘electronic marketplace’example,and Telescript agents can coex-ist and work together through the information space.‘Shops’based on bothand Telescript agents can publish catalogues and prices in the information space or accept requests for further information through an HTTP-based remote call mecha-nism.This means that users can take advantage of information available in the Telescript‘world’and vice-versa.4.3High-Level InteractionEnabling different agent infrastructures to interact through a mechanism like the information space does not solve the problem that agent developers still have to know a lot about the other agents with whom‘their’agents are going toGET/info?server:port HTTP/1.0 Authorization:Infospace-1wizard xyzzyprovide‘our’agents with support for a subset of KQML.Of course there are still many problems to be solved,e.g.,how to deﬁne the right‘ontologies’to ensure that different communicating agents actually‘understand’one another.However, the same problem also exists in homogeneous systems.This falls in the realm of AI research.The biggest challenge remains,however:Now that we can get information across the boundary between agent worlds,what about the agents themselves? References1.Dag Johansen,Robert van Renesse,and Fred B.Schneider.An Introduction to theTACOMA Distributed puter Science Technical Report95-23,Universitet Tromsø,Institute of Mathematical and Physical Sciences,Department of Computer Sci-ence,University of Tromsø,N-9037Tromsø,Norway,June1995.2.Holger Peine,Torsten Stolpmann,and J¨u rgen Nehmer.Ara:Agents for Remote Actions.See.3.Fritz Hohl.Konzeption eines einfachen Agentensystems und Implementation eines Pro-totyps.Diplomarbeit,Universit¨a t Stuttgart,August1995.4.Sahin Albayrak,Siegfried Ballmann,Indra Gunawan Harijono,and T¨o bben Hermann.InAMoS:Intelligent Agents for Mobile Services;InA V AS:Intelligent Agents for Value Added Services.See.5.James Gosling and Henry McGilton.The Java Language Environment:A White Paper.Technical Report,Sun Microsystems,1995.6.John K.Ousterhout.Tcl and the Tk Toolkit.Addison-Wesley,Reading,MA,1994.7.Mark Lutz.Programming Python.Nutshell Handbook.O’Reilly&Associates,Se-bastopol,CA.,1996.rry Wall and Randal L.Schwartz.Programming Perl.O’Reilly&Associates,Se-bastopol,CA,1990.9.General Magic,Inc.Telescript Language Reference.420North Mary Avenue,Sunny-vale,CA94086,1995.10.FTP Software.CyberAgents.See.11.Lucent Technologies.Inferno.See.12.T.Berners-Lee,R.Fielding,and H.Frystyk.Hypertext Transfer Protocol—HTTP/1.0.RFC1945,Network Working Group,May1996.13.T.Berners-Lee,R.Cailliau,A.Luotonen,H.Frystyk Nielsen,and A.Secret.The World-Wide munications of the ACM,37(8):76–82,August1994.14.James E.White.Telescript Technology:The Foundation for the Electronic Marketplace.General Magic White Paper GM-M-TSWP1-1293-V1,General Magic,Inc.,420North Mary Avenue,Sunnyvale,CA94086,1994.15.Object Management mon Object Request Broker Architecture and Speciﬁ-cations(Document no.91.12.1),1991.16.Anselm Lingnau,Oswald Drobnik,and Peter D¨o mel.An HTTP-based Infrastructurefor Mobile Agents.In Fourth International World Wide Web Conference Proceedings, number1in World Wide Web Journal,pages461–471,Boston,MA.,December1995.W3C,O’Reilly and Associates.17.T.Berners-Lee and D.Connolly.Hypertext Markup Language—2.0.RFC1866,NetworkWorking Group,November1995.18. D.Gelernter.Generative Communication in Linda.ACM Transactions on ProgrammingLanguages and Systems,7(1):80–112,January1985.。

英语作文预测移动支付业务

英语作文预测移动支付业务The Future of Mobile Payment: A Glimpse into Tomorrow。

In recent years, the realm of finance has witnessed a remarkable transformation propelled by the advent of mobile payment technologies. As smartphones become increasingly ubiquitous in our daily lives, the convenience and efficiency offered by mobile payment services have reshaped the way we conduct transactions. Looking ahead, it is undeniable that the future of mobile payment holds immense promise, revolutionizing the landscape of commerce and ushering in a new era of financial innovation.One of the most significant trends forecasted in the evolution of mobile payment services is the widespread adoption of contactless payment methods. With the proliferation of Near Field Communication (NFC) technology, consumers can now make transactions swiftly and securely by simply tapping their smartphones or wearable devices at point-of-sale terminals. This seamless integration ofpayment functionality into everyday devices not only enhances convenience for consumers but also streamlines the checkout process for merchants, reducing waiting times and improving overall operational efficiency.Moreover, the convergence of mobile payment with other emerging technologies is poised to unlock a multitude of opportunities for businesses and consumers alike. For instance, the integration of artificial intelligence and machine learning algorithms enables mobile payment platforms to analyze transaction data in real-time, thereby facilitating personalized recommendations and targeted marketing strategies. By leveraging big data analytics, merchants can gain valuable insights into consumer preferences and behavior, enabling them to tailor their offerings and enhance customer satisfaction.Furthermore, the rise of blockchain technology holds immense potential to revolutionize the security and transparency of mobile payment transactions. By utilizing decentralized ledgers, blockchain-based payment systems offer enhanced security features, protecting sensitivefinancial information from unauthorized access and mitigating the risk of fraud. Additionally, the immutable nature of blockchain ensures the integrity of transaction records, fostering trust and accountability within the payment ecosystem.Another noteworthy development in the realm of mobile payment is the proliferation of peer-to-peer (P2P) payment platforms, which enable individuals to transfer funds seamlessly between friends, family, and acquaintances. These platforms offer unparalleled convenience, allowing users to split bills, repay loans, and send monetary gifts with just a few taps on their smartphones. With the growing popularity of P2P payment services, traditional banking institutions are compelled to adapt to changing consumer preferences by enhancing their digital capabilities and offering competitive mobile banking solutions.In addition to facilitating transactions, mobile payment services are increasingly being leveraged to drive financial inclusion and empower underserved communities. In many developing regions where access to traditional bankingservices is limited, mobile payment platforms serve as a lifeline, enabling individuals to securely store, send, and receive money without the need for a conventional bank account. By bridging the gap between the unbanked population and the formal financial sector, mobile payment technologies have the potential to stimulate economic growth, foster entrepreneurship, and alleviate poverty on a global scale.However, amidst the myriad opportunities presented by the future of mobile payment, it is crucial to address the accompanying challenges and risks. Chief among these concerns is the issue of data privacy and security, as the widespread collection and storage of personal information by mobile payment providers raise legitimate concerns regarding consumer privacy and the risk of data breaches. To mitigate these risks, policymakers and industry stakeholders must collaborate to establish robust regulatory frameworks and cybersecurity protocols that safeguard user data and uphold the principles of transparency and accountability.Furthermore, the digital divide remains a significant barrier to the widespread adoption of mobile payment services, particularly in rural and underserved areas where access to reliable internet connectivity and smartphone technology is limited. To address this challenge, concerted efforts are needed to expand digital infrastructure and promote digital literacy initiatives that empower individuals to fully participate in the digital economy.In conclusion, the future of mobile payment holds immense promise as a catalyst for financial inclusion, technological innovation, and economic empowerment. By leveraging the transformative potential of mobile payment technologies, businesses and consumers can unlock new opportunities for growth, efficiency, and convenience in an increasingly interconnected world. However, realizing this vision requires a collaborative effort among policymakers, industry stakeholders, and civil society to address the challenges and risks associated with the evolution of mobile payment services, ensuring that the benefits of financial innovation are shared equitably and sustainably across society. As we embark on this journey into thefuture of finance, let us embrace the opportunities that mobile payment affords us to create a more inclusive, efficient, and prosperous world for all.。

On the Benefit of Using Mobile Technologies in Business Processes

On the Benefit of Using Mobile Technologies in Business ProcessesSina Deibert und Franz RothlaufWorking Paper 15/2006Juli 2006Working Papers in Information SystemsUniversity of MannheimDepartment of Information Systems 1D-68131 Mannheim/GermanyPhone +49 621 1811691, Fax +49 621 1811692E-Mail: wifo1@uni-mannheim.deInternet: http://www.bwl.uni-mannheim.de/wifo1On the Benefit of Using MobileTechnologies in Business ProcessesSina DEIBERT1, Franz ROTHLAUF21University of Mannheim, Schloss, Mannheim, 68131, Germany Tel: +49621-181-3535, Fax: + 49621-181-1692, Email: deibert@uni-mannheim.de2 University of Mannheim, Schloss, Mannheim, 68131, GermanyTel: +49621-181-1689, Fax: + 49621-181-1692, Email: rothlauf@uni-mannheim.deAbstract: The rapid technical progress in the development of mobile devices andtechnologies offers new possibilities for improving and streamlining the performanceof business processes. However, only few successful mobile applications exist in thebusiness area. This paper discusses the benefits an enterprise can gain by usingmobile technologies in business processes. It presents general indicators to measurethe performance of business processes and shows how these indicators must beadapted to be useful to determine the benefit of mobile applications. Then, the set ofindicators is applied in a real-world scenario. The results show that indicators likethroughput time, error rate, reduction of redundancy, and increased flexibility areimportant for the benefit of mobile technologies.1. IntroductionThe rapid technical progress in the development of mobile devices and mobile technologies offers many new possibilities for improving and streamlining the performance of business processes [11]. Due to the widespread use of mobile devices, users can always be on-line, they can always be connected to central ERP systems, non-mobile business processes can easily be substituted or extended by mobile processes, and nearly each physical item can become part of a mobile application. As over the last years the network coverage increased to a high level, these possibilities can be realized location-independently and almost everywhere [21]. However, there are tight limitations for introducing mobile technologies in business processes. An important factor for using mobile technologies in business processes is choosing the right process. Appropriate processes must be adaptable to mobile technologies and must deliver a measurable benefit for both the user and the enterprise. Without measurable additional benefit due to the introduction of a mobile technology, an enterprise will not adopt mobile technology [2]. Therefore, one of the main challenges for using mobile technologies in business processes is to determine the potential benefit that results from the introduction of mobile technologies [22]. To create successful mobile applications, an enterprise has to carefully analyze a-priori for which processes which mobile technology can result in an overall higher benefit (profit).The goal of this paper is to study the benefit that results from the use of mobile technologies in business processes. To be able to determine the potential benefit, in a first step we review existing performance indicators for business processes. Then, we examine which performance indicators are affected by the use of mobile technologies. Furthermore, we introduce additional performance indicators that take into account specific characteristics of processes supported by mobile technologies. Finally, we apply our indicators to a real-world business process in the area of a warehouse management and production system. This allows us to examine the impact of mobile technologies on business processes for one specific example (RFID tags) and to verify the benefit resultingfrom the use of mobile technology. We do this by studying various scenarios and measuring the differences between scenarios with and without mobile technologies.The paper is organized into six sections. Section 2 describes some indicators for measuring the performance of business processes. Section 3 summarizes specific properties of mobile technologies and Section 4 outlines how which indicators are appropriate to measure the quality of mobile business processes. In section 5, the performance indicators are used to determine the benefit of mobile technologies in a real-world case study.2.Performance Measurement of Business ProcessesThis section summarizes indicators for measuring the performance of business processes and discusses methods for determining their performance.2.1Indicators for Measuring the Performance of Business ProcessesTo measure the performance of a business process it is necessary to determine some indicators which represent important aspects of the process and the way in which the process is performed. In general, performance indicators can either be classified as quantitative or qualitative [6]. Quantitative indicators usually measure performance by using ordinal numbers (or a rank order) whereas qualitative indicators do not allow a direct ranking or comparison of performance aspects [19]. Common quantitative indicators are •time,•costs,•error rate,•number of performed process steps, and•stock size.There are different possibilities for measuring duration times of business processes. It is possible to measure the duration of single process steps, the time between process steps (assuming that there are waiting times), or the overall execution time of a task. Furthermore, we can count the number of process steps that must be performed to execute the entire process. [8] sub-divides performance indicators in procedure-oriented and resource-oriented categories. Both categories can be split in different sub-categories. One sub-category addresses the time aspects. These are considered in the categories operation time, holding time, and down time (resource-oriented indicators) as well as in the categories cycle time, execution time, and queue time (procedure-oriented indicators).Cost aspects are also important for determining the benefit of business processes. Examples for costs are processing costs or used capacity costs [8]. [6] argue that only time and costs aspects determine the benefit of a business process. However, there are additional indicators that are relevant for the performance of business processes like the error rate of the process. The error rate describes how many errors occur when the process is performed [18], [17]. Furthermore, it is possible to measure the process quality by counting the number of process steps that are either performed or not performed [8]. In combination with the error rate this indicator describes the robustness of the process. A process can be assumed to be robust if the process steps are correctly performed even if some errors occur. Finally, the size of the stock can be measured [16]. A lower stock size results in lower capital lockup what results in higher benefits for the enterprise.Common qualitative indicators are•process goals,•stakeholder goals,•enterprise goals,•flexibility, and•process quality.Every business process is performed to reach specific goals. In general, the quality of a business process depends on the extent these goals are reached. However, there is no unique process goal but there are different goals for different stakeholders like employees, managers, investors, or the enterprise. To determine process quality, the goals of the different stakeholders must be considered [1]. Examples for different goals are that employees are not interested in additional monitoring and controlling steps as such steps increase their work load whereas managers are interested in additional process steps to ensure a lower number of errors while performing the process. Furthermore, the goals of employees or managers do not necessarily correspond to the goals of the enterprise [19], [1]. For determining process performance, it must be measured to which extend the different goals are fulfilled. Another important qualitative performance indicator is the flexibility of the process. Flexibility measures the possibility to change the order of the process steps, to interrupt current processes, or to insert other processes without loosing data or without additional cost [12], [13]. Finally, the quality of the process is important for the benefit of the business process [3]. The quality of a business process summarizes the previous indicators and describes how well these are fulfilled. If a process coincides with the different goals and if it is flexible, it is performed well by the employees with high probability and the enterprise can gain some benefit from this process. Therefore, the quality of the process is a precondition to gain benefit from a business process.2.2On the Use of Performance Indicators for Determining the Performance of BusinessProcessesWhen using the performance indicators discussed in Section 2.1, additional factors must be considered for measuring the performance of business processes.First of all, the environment of the business process whose performance should be measured by the performance indicators must be considered. This means, it is important which tasks should be solved by the process and in which line of business the process takes place [20]. In addition, the specific business area of the process is relevant [1]. To consider the task, the line of business, and the business area are important because these different factors influence the performance of a business process.After this step, it is important to identify possible interdependencies between the different indicators. This is necessary to evaluate the impact of changes of a business process on other indicators and the corresponding process properties. Furthermore, some indicators can be based on other indicators [1] what allows an enterprise to get better information about the performance of the business process or to make a potential benefit visible. However, this also leads to interdependencies between the different indicators.After defining the indicators that should be used for measuring process performance, it is necessary to determine in which intervals the indicators should be measured and who is responsible for the measurement and the management of the information/data [23]. For the analysis of the gathered data it is also necessary to determine target values that should be met [8]. Another option is to combine the measured values with values that are obtained in previous time periods to get more meaningful results [4].Finally, the values of the indicators must be compared to target values or to results from previous periods. Using results from previous periods allows us to judge changes in the quality and benefit of a business process in comparison to previous periods. [8] emphasizes that the use of diagrams can be helpful for comparing the values of actual indicators to target values or previous values.ing Mobile Technologies in Business ProcessesThis section describes aspects that are important when using mobile technologies in business processes. These aspects influence the benefit of business processes that are supported by mobile technologies.Despite the hype of mobile technologies a few years ago, there is no significant number of business processes that are supported by mobile technology. There are many reasons for this “non-use” of mobile technologies in business processes. First, managers who decide whether a mobile technology should be introduced have no concepts and tools to determine the benefit they would gain from introducing such a new technology. Therefore, the decisions are often based on fuzzy perceptions and personal opinions of managers. Furthermore, the benefit of a business processes is often only measured at the end of the project, for example after a new technology has been implemented. This is too late and it would be more useful to determine the possible benefit of a mobile technology before the introduction of the new technology. This would give managers the possibility to change their strategy and the way in which the technology is introduced. Additionally, a-priori studies would allow designing new business processes that use mobile technologies such that they have maximum benefit for the enterprise.The following aspects must be considered before introducing mobile technologies in business processes. For successful mobile applications it is important•to choose an appropriate process,•to choose a technology that fits well to the process,•to consider specific properties of the resulting mobile application, and•to ensure a proper fit between the used mobile technology and the end-user.We will discuss these aspects briefly in the following paragraphs. First of all, not all business processes can be supported by mobile technologies in a reasonable way. It must be possible to design business processes such that mobile technologies can be used and using mobile technologies generates a measurable benefit for the enterprise and the users, respectively [2], [3].The used mobile technology must be carefully chosen. Mobile devices differ in many aspects like size of the display, input of data, available interfaces, network connections, storage possibilities, or the processing and transmitting of data. When selecting an appropriate technology, the situation in which the technology is used must be considered. For example, in noisy environments the use of display to show data should be preferred in comparison to presenting information using acoustic signals.It is important to consider specific properties of the resulting mobile application if the technology should be used by users that are inexperienced with technology. In many possible scenarios, end-users have not used mobile technologies (of even computers) before to solve their tasks. This means, that end-users only have limited skills in using mobile technologies and the resulting applications. To overcome such problems applications must be self-explanatory, easy to understand, and easy to use. Furthermore, to be fault-tolerant and to consider end-users with low experience of mobile technologies, the mobile application must be robust with respect to wrong usage [15] and it must restrict the way the end-user can use the application.Finally, a proper fit between mobile technology and end-user is important. This means, not only the fit between task and mobile technology/application must be high but also the technology must be chosen in such a way that users who have no experiences in using technologies (e.g. plumbers) are able to use the mobile application/technology. To ensure the success of a new (mobile) technology, the way in which the new technology is introduced is important. Lacking skills of end-users can be alleviated by training and by offering support and help-desks [14].We can summarize that when using mobile technologies in business processes it is necessary to choose the right processes, to use the appropriate technologies, to have a high fit between technology and user and between task and user. To address problems of inexperienced end-users, the introduction of the new technologies should be combined with trainings and additional support like help-desks.4.Impact of Mobile Technologies on the Performance of BusinessProcessesThis section describes how the use of mobile technologies can influence the performance and benefit of business processes.Indicators that are used for judging the benefit of using mobile technologies in business processes should be applicable to non-mobile variants of the process as well as to mobile-supported variants of the process. Only then, we are able to compare the benefit of business processes before and after the introduction of mobile technologies.If necessary and if the existing indicators are insufficient, new indicators must be introduced to consider the characteristics of mobile applications and mobile technologies [10]. Important indicators for studying the benefit and performance of business processes that use mobile technologies are•throughput time,•automation of work steps,•error rate,•access to information,•flexibility,•connection to the backend-system,•robustness, and•costs.On of the most important indicators for the benefit of mobile technologies is the change of the throughput time. The throughput time is influenced by most of the other indicators and is usually one of the main reasons for introducing mobile technology in business processes. Due to the automation of work steps (e.g. when RFID is used to gather data) the throughput time can be reduced because less process steps have to be performed or previously manual process steps are performed autonomously. This often also leads to a reduction of (manual) work steps by using mobile technologies. For example, in many mobile applications the manual gathering of data and the input into the backend-system can be done autonomously.As a result of higher automation of process steps the error rate of business processes is often reduced. Media breaks are avoided what leads to a lower error rate. Also the design of the mobile application has an influence on the error rate. Therefore, processes that are supported by mobile technology must be designed such that the input of data is fault tolerant and that the process and the technology restrict the way in which the data input is performed by the end-user.The use of mobile technologies in business processes also changes the access to information for the end-user. Usually, by using mobile applications and/or technologies more or better information is available anywhere and anytime. It is important to measure in which way the better access to information affects the benefit of the business process. Furthermore, the presentation and usage of information can consider the current situation of the user as applications can be context-sensitive [7].A side effect of better access to information is an increase of flexibility. This means, users can react more flexible to new situations because they have ad-hoc access to additional information. Furthermore, users or business processes can reduce waiting timesor use waiting times more effectively if they have easy access to additional information anywhere and anytime.As mobile applications can be used anywhere, the connectivity to the backend-system is relevant. To have a permanent connectivity to the backend-system or to make periodical updates are important aspects in changing environments for always having relevant data available on the mobile client. Furthermore, the quality and bandwidth of the connectivity are important for the benefit of the mobile application. A low quality of the connectivity can dramatically reduce the benefit of business processes supported by mobile technology.Using mobile technologies can have a large impact on the robustness of processes. On the one hand, robustness can be increased due to the better access to information, on the other hand, robustness can be decreased as performing tasks depends on the availability of mobile technology. Business processes can not be performed any more if there are problems with the used technology. There is a wide range of problems from insufficient battery power, no permanent access to back-end systems, up to problems with the software or operating system. For example, the substitution of paper by mobile clients can be problematic if the reliability of the mobile clients is low. In contrast to mobile applications paper is permanent, it can not crash, and it is fault-tolerant.When judging the impact of mobile technologies on business processes, the costs associated with the introduction of mobile technologies must be considered. Costs occur as a result of changing existing business processes, acquiring mobile technology, integrating mobile technologies into the business processes, training the end-user, installing help-desks, and maintaining the mobile applications. The resulting costs are important for the overall benefit of using mobile technologies in business processes.5.Case StudyWe studied the benefit of using mobile technologies in business processes for a real-word scenario. The study took place in the field of a warehouse management and production system in an enterprise for medical technology in Switzerland. The enterprise introduced a mobile technology and we have been able to study the quality of the business processes before and after the introduction of the mobile technology. In detail, a business process with manual data-input done by the employees was substituted by a business process which collects data automatically by using RFID tags. This data collection is done when storing material and products and also when producing new products. In the production process, information is collected about what type of product is produced by which producer and which material and machines are used to perform which process step.We performed the study in different steps. First, we analyzed both the original business process and the planned, mobile-supported, process based on the documents we had received from the enterprise which was responsible for implementing the mobile business process. In the next step, we identified the goals that should be reached in the original and in the mobile-supported business process. Based on these results, we chose appropriate performance indicators with respect to the used mobile technology (RFID). Then, we studied the workflow before and after the introduction of the mobile technology. We focused on error rate, flexibility, and throughput time. For measuring the flexibility of the process, we determined how often process steps became exceptional and could not be handled based on regular process steps. In addition, we compared the process steps performed in reality with the theoretical, a-priori, description of the new process. Finally, we identified the employees’ perception of the goals of the business process, their intention to use the new technology, and their personal experiences.In our study, we used existing technical documents, performed various interviews, and monitored the processes on-site. In the first step, after surveying the processes documentation, we adapted our system of performance indicators such that they fit well tothe process. The performance indicators measured the impact of the mobile technology on the efficiency of the stocking process, the error rates, the process flexibility, the number of work steps an employee has to perform when checking in or out new goods, the necessary time, and the overall profit the enterprise can expect from introducing the new technology. In the next step we made some interviews. We interviewed the project leader of the medical enterprise as well as some employees. The project leader was asked about the goals the enterprise wants to reach with the adoption of the new mobile application and about the trigger for introducing the new technology. The most important goal for the enterprise is to have better information available about the production process. (There are some rules in medical technology production which made it necessary to document the production process in detail and store the data for ten years.) With the use of RFID tags, collecting and storing of data should be done faster and with fewer mistakes. Another point is the controlling of the stock (random storage). This means they want to have better and faster information (quantity and place) about the products in stock. Furthermore, the integration of the new application in the existing ERP-System should lead to fewer problems and higher performance. Another important aspect is that they want to reduce the number of mistakes that persons make when inputting data. This is important because the details of the production process must be traceable for ten years. The trigger for introducing a mobile technology was that the management searched for a way to reach these goals. The employees were asked about their expectations and fears related to the introduction of the new technology/process.We observed the following results: First, the automatic data input increases the efficiency of the business process as the error-rates and the throughput times are lower. Furthermore, the employees are satisfied with the use of the new technology as redundant data input has been eliminated and some of the input tasks are now done automatically. Problems occurred as some of the employees who worked with the original process for many years have been afraid that the new technology allows the enterprise to monitor the employees to a higher extend because every detail of the production process is documented. This fear could be reduced by the management by confirming that the data will not be used for monitoring purposes and by making obvious that the detailed documentation of the processes is due to public law (documentation duty) and to increase the quality of the product. Interestingly, the realization of cost savings has not been an important goal for the management when introducing the mobile application. The main goals are a higher quality of the documentation and an improvement of the quality of the products due to the use of RFID. Both goals have been reached by reducing media breaks.6.ConclusionsThis paper studied indicators that are able to describe the benefit of using mobile technologies in business processes. First, we gave a short survey about general indicators for measuring business process performance. The next step was to analyse which aspects are important when using mobile technologies in business processes. Furthermore, we described specifics of mobile technologies and their effects on the benefits of business processes. Finally, we performed a case study in a real-world scenario. The results showed that using mobile technologies reduced error rate and throughput time. Crucial for using mobile technologies in business processes was a high fit between end-user and technology which could be reached by designing the mobile applications user-friendly and by offering additional support.Our further research will deal with analysing the benefit of using mobile technologies in business processes where the process structure and/or the used mobile technologies are changing. [5] studied the effect of changing the process structure without changing the technology and changing the technology without changing the process structure. Theyfound that both alternatives result in a better performance but combining both alternatives can lead to larger benefit. Furthermore, there is a higher potential for the use of mobile technologies. For applications that use real-time data or handle time-critical processes the benefit of using a mobile technology can be greater than illustrated in this study. In our future research, we analyse in which way these observations hold for other mobile applications and processes and which processes properties are important to deliver a high benefit by the use of mobile technologies.References[1] Christian Aichele. Kennzahlenbasierte Geschäftsanalyse. Gabler Verlag Wiesbaden, 1997.[2] Rahul C. Basole. The value and impact of mobile information and communication technologies. In Proceedings of the IFAC Symposium, 2004.[3] Rahul C. Basole. Mobilizing the enterprise: A conceptual model of transformational value and enterprise readiness. In ASEM National Conference Proceedings, pages 364 – 372, 2005.[4] Jerry Cha-Jan Chang and William R. King. Measuring the performance of information systems: A functional scorecard. Journal of Management Information Systems, 22(1):85–115, 2005.[5] Theodore H. Clark and Donna B. Stoddard. Interorganizational business process redesign: Merging technological and process innovation. In HICSS (4), pages 349–358, 1996.[6] Jörg Desel and Thomas Erwin. Modeling, simulation and analysis of business processes. In Business Process Management, pages 129–141, 2000.[7] A. K. Dey. Understanding and using context. Personal Ubiquitous Computing, 5(1):4–7, 2001.[8] Andreas Gadatsch. Grundkurs Geschäftsprozess-Management. Vieweg, Wiesbaden, 3. edition, 2003.[9] Judith Gebauer, Michele J. Gribbins, and Michael J. Shaw. Towards a specific theory of task-technology fit for mobile information systems - working paper, 2005.[10] Judith Gebauer and Michael J. Shaw. Success factors and impacts of mobile business applications: Results from a mobile e-procurement study. International Journal of Electronic Commerce, 8(3):19 – 41, 2004.[11] Judith Gebauer, Michael J. Shaw and Kexin Zhao. The efficacy of mobile e-procurement: A pilot study. In HICSS, page 179, 2003.[12] Christian Göbel, Armin Heinzl, and Stefan Hocke. Simulative Flexibilitätsanalyse interorganisatorischer Geschäftsprozesse. Industrie Management, 18(3):17 – 22, 2002.[13] Christian Göbel. Flexible interorganisatorische Kopplung von Geschäftsprozessen: Simulative Flexibilitätsanalyse am Beispiel einer Automotive Supply Chain. PhD thesis, Universität Bayreuth, 2003. [14] Dale Goodhue. Understanding user evaluation of information systems. Management Science, 41(12):1827 – 1844, 1995.[15] Dale Goodhue and Ronald L. Thompson. Task-technology fit and individual performance. MIS Quarterly, 19(2):213 – 236, 1995.[16] Stefan Hocke. Flexibilitätsmanagement in der Logistik – Systemtheoretische Fundierung und Simulation logistischer Gestaltungsprozesse. PhD thesis, Universität Bayreuth, 2003.[17] Markku Tinnil, Jukka Kallio, Timo Saarinen and Ari P.J. Vepslinen. Measuring delivery process performance. The International Journal of Logistics Management, 11(1):75–88, 2000.[18] Adrian Krahn, Peter Kueng, and Ambros Lüthi. Geschäftsprozessindikatoren auf der Basis von Zielen, Erfolgsfaktoren und Handlungsmöglichkeiten. Technical Report 97-06, Institut für Informatik, Universität Freiburg, 1997.[19] Peter Kueng. Process performance measurement system: a tool to support process-based organizations. Total Quality Management, 11(1):67–85, 2000.[20] Tridas Mukhopadhyay, Sunder Kekre and Suresh Kalathur. Business value of information technology: A study of electronic data interchange. MIS Quarterly, 19(2):137–156, 1995.[21] Aphrodite Tsalgatidou and Evaggelia Pitoura. Business models and transactions in mobile electronic commerce: requirements and properties. Computer Networks, 37(2):221–236, 2001.[22] Hans van der Heijden and Pablo Valiente. The value of mobility for business process performance: Evidence from Sweden and the Netherlands. In Proceedings of the European Conference on Information Systems, Gdans/Poland, 2002.[23] Karl W. Wagner. PQM - Prozessorientiertes Qualitätsmanagement, Leitfaden zur Umsetzung der ISO 9001:2000. Carl Hanser Verlag M¨unchen Wien, 2. edition, 2003.[24] Michael Zapf. Pattern-driven process designs, feb 2003.。

COMMTEST220和COMMTEST240数据收集器系统用户指南说明书

DescriptionCOMMTEST220and COMMTEST240are portable datacollector solutions that cater to non-hazardous environments.You can use these small form-factor,rugged devices to takevibration recordings and upload the collected data for detailedanalysis in System1*.The data collectors work in tandem with the S1Collector appwhich runs on an industrial smartphone hand-held device.Youcan collect vibration data,take pictures,send text messages,check your email,make phone calls and run other apps all onthe same hand-held device.The data collectors use Bluetooth to communicate with thehand-held device.The S1Collector app exchanges data withSystem1*using Wi-Fi,a cellular network,or a USB cable.You can set up your routes in System1*and sync up the datawith the app using remote communication servers.The industrial hand-held device eliminates the need for a PCor other software packages at the data collection site.It is theonly device you need to receive routes and send collected datafrom the field.You can take recordings from a predefined route as well asoff-route recordings that are not part of a route sequence.Off-route recordings may be necessary if a machine's vibrationpattern does not meet your expectations.The data collectors have a neck strap with Sensor Keeperwhich restrains your sensor while you walk or climb to reachother machines.The neck strap also has detachable safetybreakaways to protect you in case the cables are caught inrotatingmachinery.COMMTEST220&COMMTEST240Product DatasheetBently Nevada*Asset Condition MonitoringDocument:109M0792Document:109M0792Document:109M0792Document:109M0792Handheld Specificationsecom®Smart-Ex201-A Part Number111M5756ecom®Smart-Ex201-E Part Number109M8034Display 4"Gorilla Glass2 Glove touchMobile 4G/LTEQuad Band UMTS and GSMWiFi 802.11a/b/g/n Dual band WiFi Direct WiFiHotspotBlueTooth 4.0and LECameras 8MP back 1MP frontLight Camera flash LED torchSensors GPS NFCOS Android5.1CPU Quad core1.2GHzMemory 1GB RAM16GB internal storageBattery Li-Ion4800mAhUp to40hr talk timeSize 137x72x21mm 290gRuggedness IP68-20to55°CFor the latest specifications and ratings of these industrial hand-held devices,visit.The COMMTEST220and COMMTEST240 solutions include an industrial hand-held device that runs the Android operating system and uses USB,cellular,Bluetooth and Wi-Fi for communication.These solutions have features that reduce but do not eliminate cybersecurity risks.We strongly recommend implementing additional cybersecurity protections such as the following:n Controlling user accessn Scanning for virusesn Applying timely updatesn Encrypting datan Using mobile device management softwareThe recommended measures are at your discretion and responsibility.Some residual risk may remain.For more information on cybersecurity,see SCOUT200Series Installation and Operation Manual(109M1269-01).Document:109M0792For a detailed list of country and product-specificapprovals,refer to the Approvals Quick ReferenceGuide(108M1756)at .COMMTEST220-AXX-BXXA:Handheld Options00None01ecom Smart-Ex201-A(North America)02ecom Smart-Ex201-E(Europe)03Tab Active tabletB:Data Collector Approval Options00NoneThe overall hazardous system rating is defined by theminimum rating of the data collector,industrialhandheld and accessories.Metrology certification is available with yourorder.Basic KitWe offer COMMTEST220in a basic kit with theoption to purchase the System1*software andlicense separately.Additional accessories arealso available.Document:109M0792COMMTEST240-AXX-BXXA:Handheld Options00None01ecom Smart-Ex201-A(North America)02ecom Smart-Ex201-E(Europe)03Tab Active tabletB:Data Collector Approval Options00NoneThe overall hazardous system rating is defined by theminimum rating of the data collector,industrialhandheld and accessories.Metrology certification is available with yourorder.Basic KitWe offer COMMTEST220in a basic kit with theoption to purchase the System1*software andlicense separately.Additional accessories arealso available.Document:109M0792Language Specific Warning Labels110M9913Magnet base label110M9914Sensor keeper side label110M9915Sensor keeper front label111M7144Hard carrying case label Optional Accessories3071/01System1*software and license109M2387Handheld,battery-powered laser Tach for IS Zone1This item does not include a cable.You must order part number109M2389.109M2389 1.2-meter laser Tach cable for109M2387109M2391Laser Tach powered by SCOUT220-IS& SCOUT240-ISCBL502165-meter laser Tach cable for109M2391113M5529-01Reflective tapeOne roll,60cm(23.7in)111M5756ecom®Smart-Ex01-A109M8034ecom®Smart-Ex01-E113M9352-01ecom®TAB-EX US/EU113M9352-02ecom®TAB-EX AS/NZ113M9353-01Tab Active tabletDocument:109M0792Copyright2000-2018Baker Hughes,a GE Company,LLC("BHGE")All rights reserved.*Denotes a trademark of Bently Nevada,LLC,a wholly ownedsubsidiary of Baker Hughes,a GE company,a wholly ownedsubsidiary of Baker Hughes,a GE company.All product and company names are trademarks of their respectiveholders.Use of the trademarks does not imply any affiliation with orendorsement by the respective holders.The information contained in this document is subject to changewithout prior notice.1631Bently Parkway South,Minden,Nevada USA89423Phone:Document:109M0792。

英文论文投稿信Cover-letter模板

Dear Editor,We would like to submit the enclosed manuscript entitled "GDNF Acutely Modulates Neuronal Excitability and A-type Potassium Channels in Midbrain Dopaminergic Neurons", which we wish to be considered for publication in Nature Neuroscience.GDNF has long been thought to be a potent neurotrophic factor for the survival of midbrain dopaminergic neurons, which are degenerated inParkinson’s disease.In this paper, we report an unexpected, acute effect of GDNF on A-type potassium channels, leading to a potentiation of neuronal excitability, in the dopaminergic neurons in culture as well as in adult brain slices.Further, we show that GDNF regulates the K+ channels through a mechanism that involves activation of MAP kinase.Thus, this study has revealed, for the first time, an acute modulation of ion channels by GDNF.Our findings challenge the classic view of GDNF as a long-term survival factor for midbraindopaminergic neurons, and suggest that the normal function of GDNF is to regulate neuronal excitability, and consequently dopamine release.These results may also have implications in the treatment ofParkinson’s disease.Due to a direct competition and conflict of interest, we request that Drs.XXX of Harvard Univ., and YY of Yale Univ.not be considered asreviewers.With thanks for yourconsideration, I amSincerely yours,case2Dear Editor,We would like to submit the enclosed manuscript entitled "Ca2+-binding protein frequenin mediates GDNF-induced potentiation of Ca2+ channels and transmitter release", which we wish to be considered for publication in Neuron.We believe that two aspects of this manuscript will make it interesting togeneral readers of Neuron.First, we report that GDNF has a long-term regulatory effect on neurotransmitter release at the neuromuscularsynapses.This provides the first physiological evidence for a role ofthis new family of neurotrophicfactors in functional synaptic transmission.Second, we show thatthe GDNF effect is mediated byenhancing the expression of theCa2+-binding proteinfrequenin.Further, GDNF andfrequenin facilitate synaptic transmission by enhancing Ca2+channel activity, leading to an enhancement of Ca2+ influx.Thus, this study has identified, for the first time, a molecular target that mediates the long-term, synaptic action of a neurotrophic factor.Ourfindings may also have general implications in the cell biology of neurotransmitter release. [0630][投稿写作]某杂志给出的标准Sample Cover Letter[the exampleused is the IJEB]Case 3Sample Cover Letter[the exampleused is the IJEB]Dear Editor of the [please type in journal title or acronym]:Enclosed is a paper, entitled "Mobile Agents for Network Management." Please accept it as a candidate for publication in the [journal title].Below are our responses to your submission requirements.1.Title and the central theme of thearticle.Paper title: "Mobile Agents for Network Management." This studyreviews the concepts of mobileagents and distributed network management system.It proposes a mobile agent-based implementation framework and creates a prototype system to demonstrate the superior performance of a mobile agent-based network over the conventional client-server architecture in a large network environment.2.Which subject/theme of the Journalthe material fitsNew enabling technologies (if nomatching subject/theme, enter'Subject highly related to [subject of journal] but not listed by [please type in journal title or acronym])3.Why the material is important in its field and why the material should be published in [please type in journaltitle or acronym]?The necessity of having an effective computer network is rapidly growing alongside the implementation of information technology.Finding an appropriate network managementsystemhas become increasingly importanttoday's distributedenvironment.However, the conventional centralized architecture, which routinely requests the status information of local units by the central server, is not sufficient tomanage the growing requests.Recently, a new frameworkthat uses mobileagent technology to assist thedistributed management has emerged.The mobile agent reduces network traffic, distributes management tasks, and improvesoperational performance.Given today's bandwidth demand over the Internet, it is important for the[journal title/acronym] readersto understand this technology and its benefits.This study gives a real-life example of how to use mobile agentsfor distributed network management.It is the first in the literature that reports the analysis of network performance based on anoperational prototype of mobile agent-based distributed network.We strongly believe the contribution of this study warrants its publication in the [journaltitle/acronym].s, addresses, and email addresses of four expert referees.Prof.Dr.William GatesChair Professor of InformationTechnology321 Johnson Hall Premier University Lancaster, NY00012-6666, USAphone: +1-888-888-8888 - fax: +1-888-888-8886 e-mail:******************** Expertise: published a related paper ("TCP/IP and OSI: Four Strategies for Interconnection") in CACM, 38(3),pp.188-198. Relationship: I met Dr.Gate only once at a conference in 1999.I didn't knowhim personally.Assoc Prof.Dr.John AdamsDirector of Network Research Center College of Business AustralianUniversity123, Harbor Drive Sydney,Australia 56789phone: +61-8-8888-8888 - fax:+61-8-8888-8886e-mail:*************.au Expertise: published a related paper ("Creating Mobile Agents") in IEEE TOSE, 18(8), pp.88-98. Relationship: None.I have never metDr.Adams.Assoc Prof.Dr.Chia-Ho ChenChair of MIS DepartmentCollege of ManagementOpen University888, Putong RoadKeelung, Taiwan 100 phone: +886-2-8888-8888 - fax:+886-2-8888-8886e-mail:*************.tw Expertise: published a related paper ("Network Management forE-Commerce") in IJ ElectronicBusiness, 1(4), pp.18-28. Relationship: Former professor,dissertation chairman.Mr.Frank YoungPartner, ABC Consulting888, Seashore HighwayWon Kok, KowloonHong Kongphone: +852-8888-8888 - fax:+852-8888-8886e-mail:***************Expertise: Mr.Young provides consulting services extensively to his clients regarding networkmanagement practices. Relationship: I have worked withMr.Young in several consultingprojects in the past three years. Finally, this paper is our originalunpublished work and it has not been submitted to any other journal forreviews.Sincerely,Johnny Smith。

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USING MOBILE AGENTS FOR OFF-LINE COMMUNICATION AMONG MOBILE HOSTS IN A LARGE, HIGHLY-MOBILEDYNAMIC NETWORKSS. BandyopadhyaySaltlake Technology CenterPricewaterhouseCoopersSector V, SaltlakeCalcutta 700 091 INDIAABSTRACTIn dynamic networks such as packet radio and ad-hoc wireless network, each node acts as a mobile router, equipped with a wireless transmitter / receiver, which is free to move about arbitrarily. In this configuration, even if two nodes are outside the wireless transmission range of each other, they can still be able to communicate with each other in multiple hops, if other intermediate nodes in the network are willing to participate in this communication process. However, the dynamics of these networks as a consequence of mobility and disconnection of mobile hosts pose a number of problems in designing routing schemes for effective communication between any source and destination. Thus, even off-line communication between source and destination (e-mail, for example) would be inefficient, if not impossible, in a large dynamic network structure where hosts are highly mobile. This paper introduces a scheme using mobile agent to address this issue. Mobile agent in this context would act as a messenger that would migrate from a source and carry the message from a source to a destination. The scheme utilizes the location information (using the global positioning system, for example) and relies on the fact that the mobility of hosts in ad hoc networks are not totally random but follow a pattern of movement. A mobile agent can migrate off a source node with a message and navigate autonomously throughout the network to find out the destination in order to deliver this message. If the destination is disconnected from the network for some duration, the delivery of message will be deferred and the agent waits for its reconnection in an appropriate intermediate node. From the performance evaluation, it has been concluded that the proposed scheme consumes much less network resource compared to other routing schemes proposed in the context of highly dynamic large ad hoc network.1.INTRODUCTIONA mobile agent is a program that can move through a network under its own control, capable of navigating through the underlying network and performing various tasks at each node independently [1]. Mobile agents are an effective paradigm for distributed applications, and are particularly attractive in a dynamic network environment involving partially connected computing elements [2]. InK. PaulTechna Digital SystemsSDF Building, Sector VSaltlakeCalcutta 700 091 INDIAthis paper, we propose to use mobile agents for off-line message transfer among mobile hosts in a large, highly-mobile dynamic networksIn dynamic networks such as packet radio and ad-hoc wireless network, each node acts as a mobile router, equipped with a wireless transmitter / receiver, which is free to move about arbitrarily. In this configuration, even if two nodes are outside the wireless transmission range of each other, they can still be able to communicate with each other in multiple hops, if other intermediate nodes in the network are willing to participate in this communication process. Thus, the notion of static base-stations and centralized control to manage host mobility is no longer a key requirement in this environment [3]. However, the dynamics of these networks as a consequence of mobility and disconnection of mobile hosts pose a number of problems in designing routing schemes for effective communication between any source and destination [5,6]. The conventional routing protocols that require to know the topology of the entire network is not suitable in such a highly dynamic environment, since the topology update information needs to be propagated frequently throughout the network. On the other hand, a demand-based route discovery procedure generates large volume of control traffic. In a highly mobile environment with a large number of nodes, even if a route is discovered, a route rediscovery needs to be initiated when an intermediate node, participating in a communication between two nodes, moves out of range suddenly or switches itself off in between message transfer [3]. An additional problem is the occurrence of disconnected component within a network, where a destination is not at all accessible by a source at some instance of time. This has been shown in the simulated environment in [3] that the occurrences of disconnected components increase the protocol overhead due to the generation of unproductive route request packets. Thus, even off-line communication between source and destination (e-mail or file transfer, for example) would be inefficient, if not impossible, in a large dynamic network structure where hosts are highly mobile. This paper introduces a scheme using mobile agent to address this issue.Currently, there is a growing interest in using mobile agents as part of the solution to implement more flexible anddecentralized network architecture [1]. Most researchexamples of the mobile agent paradigm as reported in thecurrent literatures have two general goals: reduction ofnetwork traffic and asynchronous interaction. Magedanz etal. [7] has suggested that a smart message agent can serve as an asynchronous message carrier for its owner (e.g., retrievee-mail asynchronously and forward to the current location ofthe owner), or as a broker that requests and sets up allrequirements for services (e.g., establishes a real-timeconnection for media delivery). Recent interests in theapplication of mobile agent in mobile computingenvironment suggest that mobile agent can be an effectiveparadigm for distributed applications, where partiallyconnected computers are involved [2]. However, the use ofmobile agent in the context of multi-hop ad hoc wirelessnetwork has not been explored. In this paper, we attempt toshow the effective use of mobile agent for off-line message communication in the context of highly dynamic, large adhoc network.Mobile agent in this context would act as a messenger that would migrate from a source and carry the message from a source to a destination. The scheme utilizes the location information (using the global positioning system, for example) and relies on the fact that the mobility of hosts in ad hoc networks are not totally random but follow a pattern of movement [4]. A mobile agent can migrate off a source node with a message and navigate autonomously throughout the network to find out the destination in order to deliver this message. The agent has an approximate knowledge about the location of destination and takes the advantage of host-mobility as a vehicle to physically migrate from one location to other. If the destination is disconnected from the network for some duration, the delivery of message will be deferred and the agent waits for its reconnection in an appropriate intermediate node.The performance of this scheme is evaluated in a simulated environment. It has been concluded that in a highly mobile , large ad-hoc wireless network, this scheme consumes much less network resource compared to other routing schemes proposed in the context of ad hoc network.2. SYSTEM DESCRIPTIONThe network is modeled as a graph G = (N,L) where N is afinite set of nodes and L is a finite set of links. Each node n∈ N is having a unique node identifier. We define the neighbors of n, N n∈N, to be the set of nodes within the transmission range of n. It is assumed that when node ntransmit a packet, it is broadcast to all of its neighbors in theset N n.Each node is assumed to have a home location. Generallyspeaking, home location is the most preferred location of a node where it normally resides. It means that even if a node is mobile, it eventually comes back to its home location.It is assumed that each node knows its position using Global Positioning System (GPS) [8]. The use of GPS in the context of routing in ad hoc network has been proposed earlier in [8]. In this paper, it is also assumed that a node keeps track of the positions of its neighbors.It has been observed earlier [4] that a node does not have a communication relationship with all the other nodes in the network; a node usually communicates with a limited number of nodes (patron host in [4]) in the network. Thus, it is assumed that a source node knows the home locations of its intended destination. If it does not know, a route request is generated [3] and the route reply carries the home location information. This would be useful for the source node in subsequent communications with the same destination.3. A MECHANISM FOR AGENT CREATION ANDNAVIGATION3.1 The Structure of a NodeIn order to facilitate agent’s navigation for message communication, each node is assumed to have the following structure:Node Id (n)Home Location (x n home, y n home)Transmission Range (R)Current Location (x n, y n)Information about Neighbors (p) :(for all p : p, x n p, y n p )Home Locations of Potential Destinations (d):(for all d : x d home, y d home )Each node is assumed to know its id, home location, transmission range and current location (through GPS). Each node transmits a periodic message to its neighbors to inform its id, current location. The receiving node appends this information (for all p : p, x n p, y n p).Home locations of potential destinations may not be known initially. As indicated earlier, a request is initiated to search the destination ( as is done in case of route discovery [[3]) to know the home location of the destination.3.2 Agent Creation at the Initiator (source) NodeWhenever a node wants to send a message to another node which is not its neighbor, an agent is created as message carrier. The structure of the agent is :Sender’s Id and Home LocationReceiver’s Id and Home LocationNavigation ProcedureThe Body of the Message from Sender3.3 Basic Navigation ProcedureThe objective of the navigation procedure is to minimize the distance between the agent’s current location (current location of the node where the agent is residing) and the home location of the destination. This criterion would enable an agent to select a neighbor of its current location and migrate there. If there is no neighbor available at that instant of time satisfying the above-mentioned criterion, the agent waits for a pre-specified amount of time and tries again. Because of high degree of node-mobility, the topology will change, and, it is assumed that the agent will eventually succeed to migrate.For example, If the current location of an agent is (15,25), locations of three of its physical neighbors are (10,15), (30, 35) and (20, 30), and, home location of the destination is (65, 75), the agent would migrate to the node whose location is (30,35), since this migration would reduce the distance between the current location of the agent and the home location of the destination node. However, if the current location has two physical neighbors with locations (10,15) and (5,20), the agent would wait (since its current location is preferable to match the criterion) and retry after some time. Most of the time the agent would not find the destination node at its home location. In that case, the agent has to wait in some node near the home location of the destination. However, because of the node-mobility, that node near the home location of the destination might move away. In that case, the agent would migrate to some other node following the same criterion of minimizing the distance with the home location of the destination. This migrate-wait loop would continue until the destination node reaches its home location and the message is delivered.On successful delivery of the message at the destination node, an agent would terminate itself. If the agent can not deliver the message within a pre-specified amount of time, the agent would try to go back to the source node reporting a delivery failure and then terminate itself. However, it may so happen that the agent can not deliver this ‘delivery failure’message also to its source node because of the mobility pattern of the source node. In that case, the agent would terminate itself after a pre-specified amount of time in order to reduce network load.4. PERFORMANCE EVALUATIONThe performance of the proposed scheme is evaluated on a simulated environment. In the simulation, the environment is assumed to be a closed area of 1000 x 1000 unit in which mobile nodes are distributed randomly. In order to study the delay and other time-related parameters, every simulated action is associated with a simulated clock of one second. Each node has been assumed to move at the rate of 30 units/sec. or 10 units/sec. in the specified area. We have deliberately chosen a high mobility pattern in order to study the effectiveness of the scheme. The neighborhood relationship is updated every second and accordingly the migration pattern of an agent is decided.We ran simulations for networks of sizes 20, 40 and 60 mobile hosts with range of transmission varying from 50 to 150 unit in each case. Each node starts from its home location, selects a random location as its destination and moves with a uniform, predetermined velocity towards the destination. Once it reaches the destination, it waits there for a pre-specified amount of time, selects randomly another location and moves towards that. After a few movements in this fashion, the node selects its home location and comes back to its home location. After all the nodes reach back to their home locations in this fashion, a session is said to be complete. During a session, several source-destination pairs are selected randomly for message communication. The pattern and speed of movements are different for different settings with a mobility rate of individual node ranging from 10 to 30 units per second.First, we have selected arbitrary source-destination pairs and studied the time taken by an agent, initiated by a source, to reach within the transmission range of the home location of the destination node. As discussed earlier, the success of the scheme depends on two factors : i) the agent, initiated by a source, should reach within the transmission range of the home location of the destination node quickly; and, ii) it should continue to stay within the transmission range of the home location, waiting for the destination node to reach its home location. Figure 1 shows the behavioral pattern of an agent for an arbitrary source-destination pair for different transmission range (R) and different number of nodes (N) in each case. . The initial distance between source and the home location of the destination was 660, when an agent was initiated. For R=50, it takes much longer time for an agent to come within the home location of the destination compared to R=100 or R=150. For R=50 and N=20, it is even uncertain to predict whether the agent would remain within the transmission range of the home location of the destination. The reason is, for low R and low N, there are situations when the agent is not finding any proper intermediate node to migrate in order to reach near the home location of the destination. Even at R=50, the situation is better when N is high (N=60, for example).Situation is much better when R=150. At all node density (N=20,40,60), the convergence time is low; at the same time, it is evident from figure 1 that the agent will always remain within the transmission range of the home location of the destination, waiting for the destination to deliver the message. Next, we have studied the average number of hops an agent would require to deliver a message to a destination node. A set of source-destinatin pairs are selected and each source initiates an agent at T=0. Three cases have been studied where each destination has been forced to reach its home location approximately at i) T=50, ii) T=100, and iii)T=200.100200300400500600700161116212631364146515661667176TimeD i s t a n c e (S o u r c e & D e s t i n a t i o n )n=20n=40n=60100200300400500600700161116212631364146515661667176Timen=20n=40n=600100200300400500600700161116212631364146515661667176TimeD i s t a n c e (S o u r c e & D e s t i n a t i o n )n=20n=40n=60Transmission Range = 50Transmission Range = 100Transmission Range = 150Figure 1. Time taken to reach within the transmission range of the home location of a destination from an arbitrary source at mobility rate 30 units / sec.In each case, the transmission range is 150 unit; however, the number of nodes and mobility are different (Figure 2). This is an important study to see the amount of traffic generated within the network during this agent-based communication.Form Figure 2, it is interesting to note that the number of hops does not depend on the number of nodes. Since an agent always migrate to one “appropriate neighbor”, the number of hops does not depends on number of nodes in the system. This is in contrast with the existing routing algorithms, where the control traffic generated grows up drastically with increase in node density.A second interesting observation is that the incremental number of hops with increase in T is approx. 10 hops per 100 seconds i.e. 1 hop per 10 seconds. Thus, even if the destination reaches its home location after a long time, the overhead in terms of communication resource utilization by an agent, waiting to deliver a message, is not significant.When mobility is low, number of hops are less compared to the situations where mobility is high. This is expected, because,more dynamic is the network, more number of intermediate hops would be required by an agent to converge.5. CONCLUSIONIf the nodes in the network are less mobile or the size of the network is small, existing routing protocols designed in the context of ad hoc multi-hop networks work well. However, as discussed earlier, for a large, highly dynamic ad hoc network where each node has a pre-defined home location, agent-based scheme for message delivery is much more efficient and effective, exploiting the basic theme of mobile agent paradigm: reduction of network traffic and ease of asynchronous interaction.REFERENCES[1] Vu Anh Pham and Ahmed Karmouch, Mobile Software Agents: An Overview, IEEE Communication Magazine, July, 1998.[2] R.Gray, D.Kotz, S.Nog and G.Cybenko, Mobile agents for mobile computing, Technical Report PCS-TR96-285, Department of Computer Science, Dartmouth College,Hanover, NH 03755, May, 1996.[3] D. B. Johnson and D. Maltz, Dynamic source routing in ad hoc wireless networks, T. Imielinski and H. Korth, eds.,Mobile computing, Kluwer Academic Publ. 1996.[4] G. Cho and L.F. Marshall, An Efficient Location and Routing Scheme for Mobile Computing Environments, IEEE Journal on Selected Areas in Communications, Vol.13, No.5,June 1995.[5] Z. J. Haas, Milcom’97 Panel on Ad-hoc Networks,/~haas/milcom_panel.html [6] S. Corson, J. Macker and S. Batsell, Architectural considerations for mobile mesh networking, Internet Draft RFC Version 2, May 1996.[7] T. Magedanz, K. Rothermel, and S. Krause,"Intelligent Agents: An Emerging Technology for Next Generation Telecommunications?" Proc. INFOCOM'96, San Francisco, CA, 1996.[8] Y.-Bae Ko and N.H. Vaidya, Location-aided Routing in Mobile Ad hoc Networks, Tech. Rep. TR-98-012, Dept. of Computer Science, Texas A&M University, June, 1998.10203040406080Number of NodesT=200T=100T=50510152025406080Number of NodesT=200T=100T=50Mobility = 30Mobility=10Figure 2. Average number of hops required by an agent to reach a destination node from a source node where T is average time taken by the destination to reach its home location。