毕业设计英文 翻译(原文)
本科毕业设计英文翻译
翻译部分英文原文SELF-ADVANCING HYDRAULIC POWERED SUPPORTSModern longwall mining employs hydraulic powered supports at the face area . The support not only holds up the roof , pushes the face chain conveyor , and advances itself , but also provides a safe environment for all associated mining activities . Therefore its successful selection and application are the prerequisite for successful longwall mining . Furthermore , due to the large number of units required , the capital invested for the powered support usually accounts for more than half of the initial capital for a longwall face . Therefore both from technical and economic points of view , the powered support is a very important piece of equipment in a longwall face .The application of modern powered supports can be traced back to the early 1950’s . Since then , following its adoption in every part of the world , there have been countless models designed and manufactured in various countries . But unfortunately , there still is no uniform system of classification .A simplified classification is used in this section . since a powered support consists of four major components(i. e. , canopy , caving shield , hydraulic legs or props , and base plate ) , the ways by which they are interrelated are used for classification . In this respect , two factors are most important : (1) presence or absence of a caving shield - if a caving shield is included , the support is a “ shield ”type , otherwise , a frame or a chock ; (2) number and type of arranging the hydraulic legs - since support capacity is generally proportional to the number of hydraulic legs , it is important to specify the number of hydraulic legs that a support has . Furthermore , the way the hydraulic legs are installed is important ; for example , a vertical installation between the base and the canopy has the highest efficiency of application whereas an inclined installation between the base and the caving shield has the least efficiency in supporting the roof .Based on this concept , there are four types of powered support , that is , the frame , chock , shield , and chock shield , in order of evolution of their development . However , it must be noted that the trend of development in each type is such that it becomes less distinguishable in terms of application .The four types of roof supports can be obtained for either longwall retreating or advancing systems , and they are available in standard , one-web-back , and immediate forward support ( IFS ) versions .With the standard system , the winning machine takes a cut or a slice , and the armored face conveyor is pushed over by the hydraulic rams that are fixed to the support units . The support units then are advanced sequentially to the conveyor . With the one-web-back system , a support is set back from the conveyor by a device that automatically keeps the leading edge of the support at a fixed distance from the conveyor .This allows easy access through the face and employs the standard method of advancing ; i. e. , pushing the conveyor first , and then advancing the support .With the IFS system , the support unit is advanced to the conveyor immediately after the cutting machine has passed , and the forward canopy of the support unit is long enough to support both the recently and newly exposed roof sections . After the supports have been advanced , the conveyor is pushed over .FRAMEThe frame support is an extension of the single hydraulic props conventionally used underground . Thus it is the first type developed in modern self-advancing hydraulic powered supports .It involves setting up two hydraulic props or legs vertically in tandem that are connected at the top by a single or two segmented canopies .The two segmented canopies can be hinge-jointed at any point between the legs or in front of the front leg .The base of the two hydraulic legs may be a circular steel shoe welded at bottom of each leg or a solid base connecting both legs (Fig .8.8) .Generally , a frame support consists of two or three sets of hydraulic legs . The set moving first is the secondary set , the set moving later is the primary set .There is a double-acting ram installed between each set . The piston of the ram is connected to the secondary set and the cylinder to the primary set . During support advance ( Fig. 8.9) , the primary set is set against the roof while the secondary set is lowered and pushed forward by the piston . Having reached the new position , the secondary set is set against the roof while the primary set is lowered and pulled forward by the cylinder . The distance of each advance ranges from 20 to 36 in. (0.50~0.91m) .Fig . 8.8 Frame supporta-primary set b-secondary setA B CFig . 8.9 Method of advancing the frame supportThe frame support is very simple , but more flexible or less stable structurally . There are considerable uncovered spaces between the two pieces of canopy which allows broken roof rock to fall through . Consequently , the frame support is not suitable for a weak roof . Frames have become seldom used because they are less stable and require frequent maintenance .CHOCKIn a chock support , the canopy is a solid piece and the base may be either a solid piece or two separate parts connected by steel bars at the rear and / or the front ends . In both cases a large open space is left at the center for locating the double-acting hydraulic ram which is used to push and pull the chain conveyor and the chock in a whole unit ,respectively , a distinctive difference from the frame support . This setupdesigned for thin seams with two legs in the front and four legs in the rear , separated by awalkwa is also used in the shields and chock shields .Again , all hydraulic legs are installed vertically between the base and the canopy (Fig. 8. 10) . The number of legs ranges from three to six , but the four-leg chocks are by far the most popular ones . The six-leg chocks are y (Fig. 8.10c) . For the six-leg chocks , the canopy is generally hinge-jointed above the walkway . Most chock are also equipped with a gob window hanging at the rear end of the canopy . The gob window consists of several rectangular steel plates connected horizontally at both ends.A B CFig . 8.10 Schematics of various chock supportIn most chock supports , there are hinge joint connections between the legs and the canopy and between the legs and the base . But in order to increase the longitudinal stability , it is reinforced mostly with a box-shaped steel frame between the base and each leg . A leg restoring device is installed around each leg at the top of the box-shaped steel frame .The chocks are suitable for medium to hard roof . When the roof overhangs well into the gob and requires induced caving , the chocks can provide access to the gob .SHIELDShields , a new entry in the early seventies , are characterized by the addition of a caving shield at the rear end between the base and the canopy . The caving shields , which in general are inclined , are hinge-jointed to the canopy and the base making the shield a kinematically stable support , a major advantage over the frames and the chocks . It also completely seals off the gob and prevents rock debris from getting into the face side of the support . Thus the shield-supported face is generally clean .The hydraulic legs in the shields are generally inclined to provide more open space for traffic . Because the canopy , caving shield , and base are interconnected , it can well resist the horizontal force without bending the legs . Thus , unlike the solid constraint in the frame/ chock supports , the pin connections between the legs and the canopy ,and between the legs and the base in a shield support make it possible that the angle of inclination of the hydraulic legs varies with the mining heights . Since only the vertical component of hydraulic leg pressure is available for supporting theroof ,the actual loading capacity of the shield also varies with the mining heights .There are many variations of the shield supports . In the following ,six items areused to classify the shields , which enables a unified terminology to be developed for all kinds of shields . The types of motional traces of the canopy tip , leg positions and orientation , number of legs , canopy geometry , and other optional designs and devices can be clearly specified by the terminology .TYPES OF MOTIONAL TRACES FOR THE LEADING EDGE OF THE CANOPY.This is the most commonly recognized way of classifying the shield . Based on this criterion , there are three types , lemniscate , caliper , and ellipse (Fig. 8. 11) .A . Lemniscate.LB . Caliper.C C . Ellipse.EFig . 8.11 Three types of motional traces for leading edge of the shield canopyA . Lemniscate . This is the most popular type . The caving shield and the base are jointed by two lemniscate bars which have a total of four hinges . As the hydraulic legs are raised and lowered , the dimentions of the lemniscate bars are selected such that the leading edge of the canopy moves up and down nearly vertically , thus maintaining a nearly constant unsupported distance between the face-line and the leading edge of the canopy .This is a feature that is widely considered most desirable for good roof control . There are clear limits of mining height within which the leading edge of the canopy moves nearly vertically . These limits are strictly controlled by the dimentional and positional arrangements of the canopy , caving shield , lemniscate bars , and the base . Beyond these limits , the edges will move rapidly away from the face-line creating a large unsupported area .B . Caliper . In a caliper shield , the caving shield and the base are connected by a single hinge .When the hydraulic legs are raised , the leading edge of the canopy moves in an arc away from the face , thus increasing the unsupported area This is considered by most users the least desirable feature of the caliper shield But in practice if the seam thickness varies little , the dimentional and positional arrangement of canopy , caving shield , and the base can be so designed that the distance change of unsupported area will not be significant . On the other hand , when the legs are lowered , it reduces the unsupported area .C . Ellipse . In this type the caving shield and the base are so connected that when the hydraulic legs are moved up and down , the leading edge of the canopy follows an elliptical trace . This type is seldom used .CHOCK SHIELDThe chock shield combines the features of the chocks and the shields . As such it possesses the advantages of both .If all of the four or six legs are installed between the canopy and the base , it is called a chock shield . There are regular four or six-leg chock shields in which all legs are vertical and parallel . Others form V or X shapes . Some canopies are a single piece and some are two pieces with a hydraulic ram at the hinge joint . The chock shield has the highest supporting efficiency . They are suitable for hard roof .中文译文自移式液压支架液压支架广泛应用于现代长臂采煤工作面上。
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A Design and Implementation of Active NetworkSocket ProgrammingK.L. Eddie Law, Roy LeungThe Edward S. Rogers Sr. Department of Electrical and Computer EngineeringUniversity of TorontoToronto, Canadaeddie@, roy.leung@utoronto.caAbstract—The concept of programmable nodes and active networks introduces programmability into communication networks. Code and data can be sent and modified on their ways to destinations. Recently, various research groups have designed and implemented their own design platforms. Each design has its own benefits and drawbacks. Moreover, there exists an interoperability problem among platforms. As a result, we introduce a concept that is similar to the network socket programming. We intentionally establish a set of simple interfaces for programming active applications. This set of interfaces, known as Active Network Socket Programming (ANSP), will be working on top of all other execution environments in future. Therefore, the ANSP offers a concept that is similar to “write once, run everywhere.” It is an open programming model that active applications can work on all execution environments. It solves the heterogeneity within active networks. This is especially useful when active applications need to access all regions within a heterogeneous network to deploy special service at critical points or to monitor the performance of the entire networks. Instead of introducing a new platform, our approach provides a thin, transparent layer on top of existing environments that can be easily installed for all active applications.Keywords-active networks; application programming interface; active network socket programming;I. I NTRODUCTIONIn 1990, Clark and Tennenhouse [1] proposed a design framework for introducing new network protocols for the Internet. Since the publication of that position paper, active network design framework [2, 3, 10] has slowly taken shape in the late 1990s. The active network paradigm allows program code and data to be delivered simultaneously on the Internet. Moreover, they may get executed and modified on their ways to their destinations. At the moment, there is a global active network backbone, the ABone, for experiments on active networks. Apart from the immaturity of the executing platform, the primary hindrance on the deployment of active networks on the Internet is more on the commercially related issues. For example, a vendor may hesitate to allow network routers to run some unknown programs that may affect their expected routing performance. As a result, alternatives were proposed to allow active network concept to operate on the Internet, such as the application layer active networking (ALAN) project [4] from the European research community. In the ALAN project, there are active server systems located at different places in the networks and active applications are allowed to run in these servers at the application layer. Another potential approach from the network service provider is to offer active network service as the premium service class in the networks. This service class should provide the best Quality of Service (QoS), and allow the access of computing facility in routers. With this approach, the network service providers can create a new source of income.The research in active networks has been progressing steadily. Since active networks introduce programmability on the Internet, appropriate executing platforms for the active applications to execute should be established. These operating platforms are known as execution environments (EEs) and a few of them have been created, e.g., the Active Signaling Protocol (ASP) [12] and the Active Network Transport System (ANTS) [11]. Hence, different active applications can be implemented to test the active networking concept.With these EEs, some experiments have been carried out to examine the active network concept, for example, the mobile networks [5], web proxies [6], and multicast routers [7]. Active networks introduce a lot of program flexibility and extensibility in networks. Several research groups have proposed various designs of execution environments to offer network computation within routers. Their performance and potential benefits to existing infrastructure are being evaluated [8, 9]. Unfortunately, they seldom concern the interoperability problems when the active networks consist of multiple execution environments. For example, there are three EEs in ABone. Active applications written for one particular EE cannot be operated on other platforms. This introduces another problem of resources partitioning for different EEs to operate. Moreover, there are always some critical network applications that need to run under all network routers, such as collecting information and deploying service at critical points to monitor the networks.In this paper, a framework known as Active Network Socket Programming (ANSP) model is proposed to work with all EEs. It offers the following primary objectives.• One single programming interface is introduced for writing active applications.• Since ANSP offers the programming interface, the design of EE can be made independent of the ANSP.This enables a transparency in developing andenhancing future execution environments.• ANSP addresses the interoperability issues among different execution environments.• Through the design of ANSP, the pros and cons of different EEs will be gained. This may help design abetter EE with improved performance in future.The primary objective of the ANSP is to enable all active applications that are written in ANSP can operate in the ABone testbed . While the proposed ANSP framework is essential in unifying the network environments, we believe that the availability of different environments is beneficial in the development of a better execution environment in future. ANSP is not intended to replace all existing environments, but to enable the studies of new network services which are orthogonal to the designs of execution environments. Therefore, ANSP is designed to be a thin and transparent layer on top of all execution environments. Currently, its deployment relies on automatic code loading with the underlying environments. As a result, the deployment of ANSP at a router is optional and does not require any change to the execution environments.II. D ESIGN I SSUES ON ANSPThe ANSP unifies existing programming interfaces among all EEs. Conceptually, the design of ANSP is similar to the middleware design that offers proper translation mechanisms to different EEs. The provisioning of a unified interface is only one part of the whole ANSP platform. There are many other issues that need to be considered. Apart from translating a set of programming interfaces to other executable calls in different EEs, there are other design issues that should be covered, e.g., • a unified thread library handles thread operations regardless of the thread libraries used in the EEs;• a global soft-store allows information sharing among capsules that may execute over different environmentsat a given router;• a unified addressing scheme used across different environments; more importantly, a routing informationexchange mechanism should be designed across EEs toobtain a global view of the unified networks;• a programming model that should be independent to any programming languages in active networks;• and finally, a translation mechanism to hide the heterogeneity of capsule header structures.A. Heterogeneity in programming modelEach execution environment provides various abstractions for its services and resources in the form of program calls. The model consists of a set of well-defined components, each of them has its own programming interfaces. For the abstractions, capsule-based programming model [10] is the most popular design in active networks. It is used in ANTS [11] and ASP [12], and they are being supported in ABone. Although they are developed based on the same capsule model, their respective components and interfaces are different. Therefore, programs written in one EE cannot run in anther EE. The conceptual views of the programming models in ANTS and ASP are shown in Figure 1.There are three distinct components in ANTS: application, capsule, and execution environment. There exist user interfaces for the active applications at only the source and destination routers. Then the users can specify their customized actions to the networks. According to the program function, the applications send one or more capsules to carry out the operations. Both applications and capsules operate on top of an execution environment that exports an interface to its internal programming resources. Capsule executes its program at each router it has visited. When it arrives at its destination, the application at destination may either reply it with another capsule or presents this arrival event to the user. One drawback with ANTS is that it only allows “bootstrap” application.Figure 1. Programming Models in ASP and ANTS.In contrast, ASP does not limit its users to run “bootstrap” applications. Its program interfaces are different from ANTS, but there are also has three components in ASP: application client, environment, and AAContext. The application client can run on active or non-active host. It can start an active application by simply sending a request message to the EE. The client presents information to users and allows its users to trigger actions at a nearby active router. AAContext is the core of the network service and its specification is divided into two parts. One part specifies its actions at its source and destination routers. Its role is similar to that of the application in ANTS, except that it does not provide a direct interface with the user. The other part defines its actions when it runs inside the active networks and it is similar to the functional behaviors of a capsule in ANTS.In order to deal with the heterogeneity of these two models, ANSP needs to introduce a new set of programming interfaces and map its interfaces and execution model to those within the routers’ EEs.B. Unified Thread LibraryEach execution environment must ensure the isolation of instance executions, so they do not affect each other or accessThe authors appreciate the Nortel Institute for Telecommunications (NIT) at the University of Toronto to allow them to access the computing facilitiesothers’ information. There are various ways to enforce the access control. One simple way is to have one virtual machine for one instance of active applications. This relies on the security design in the virtual machines to isolate services. ANTS is one example that is using this method. Nevertheless, the use of multiple virtual machines requires relatively large amount of resources and may be inefficient in some cases. Therefore, certain environments, such as ASP, allow network services to run within a virtual machine but restrict the use of their services to a limited set of libraries in their packages. For instance, ASP provides its thread library to enforce access control. Because of the differences in these types of thread mechanism, ANSP devises a new thread library to allow uniform accesses to different thread mechanisms.C. Soft-StoreSoft-store allows capsule to insert and retrieve information at a router, thus allowing more than one capsules to exchange information within a network. However, problem arises when a network service can execute under different environments within a router. The problem occurs especially when a network service inserts its soft-store information in one environment and retrieves its data at a later time in another environment at the same router. Due to the fact that execution environments are not allowed to exchange information, the network service cannot retrieve its previous data. Therefore, our ANSP framework needs to take into account of this problem and provides soft-store mechanism that allows universal access of its data at each router.D. Global View of a Unified NetworkWhen an active application is written with ANSP, it can execute on different environment seamlessly. The previously smaller and partitioned networks based on different EEs can now be merging into one large active network. It is then necessary to advise the network topology across the networks. However, different execution environments have different addressing schemes and proprietary routing protocols. In order to merge these partitions together, ANSP must provide a new unified addressing scheme. This new scheme should be interpretable by any environments through appropriate translations with the ANSP. Upon defining the new addressing scheme, a new routing protocol should be designed to operate among environments to exchange topology information. This allows each environment in a network to have a complete view of its network topology.E. Language-Independent ModelExecution environment can be programmed in any programming language. One of the most commonly used languages is Java [13] due to its dynamic code loading capability. In fact, both ANTS and ASP are developed in Java. Nevertheless, the active network architecture shown in Figure 2 does not restrict the use of additional environments that are developed in other languages. For instance, the active network daemon, anted, in Abone provides a workspace to execute multiple execution environments within a router. PLAN, for example, is implemented in Ocaml that will be deployable on ABone in future. Although the current active network is designed to deploy multiple environments that can be in any programming languages, there lacks the tool to allow active applications to run seamlessly upon these environments. Hence, one of the issues that ANSP needs to address is to design a programming model that can work with different programming languages. Although our current prototype only considers ANTS and ASP in its design, PLAN will be the next target to address the programming language issue and to improve the design of ANSP.Figure 2. ANSP Framework Model.F. Heterogeneity of Capsule Header StructureThe structures of the capsule headers are different in different EEs. They carries capsule-related information, for example, the capsule types, sources and destinations. This information is important when certain decision needs to be made within its target environment. A unified model should allow its program code to be executed on different environments. However, the capsule header prevents different environments to interpret its information successfully. Therefore, ANSP should carry out appropriate translation to the header information before the target environment receives this capsule.III. ANSP P ROGRAMMING M ODELWe have outlined the design issues encountered with the ANSP. In the following, the design of the programming model in ANSP will be discussed. This proposed framework provides a set of unified programming interfaces that allows active applications to work on all execution environments. The framework is shown in Figure 2. It is composed of two layers integrated within the active network architecture. These two layers can operate independently without the other layer. The upper layer provides a unified programming model to active applications. The lower layer provides appropriate translation procedure to the ANSP applications when it is processed by different environments. This service is necessary because each environment has its own header definition.The ANSP framework provides a set of programming calls which are abstractions of ANSP services and resources. A capsule-based model is used for ANSP, and it is currently extended to map to other capsule-based models used in ANTSand ASP. The mapping possibility to other models remains as our future works. Hence, the mapping technique in ANSP allows any ANSP applications to access the same programming resources in different environments through a single set of interfaces. The mapping has to be done in a consistent and transparent manner. Therefore, the ANSP appears as an execution environment that provides a complete set of functionalities to active applications. While in fact, it is an overlay structure that makes use of the services provided from the underlying environments. In the following, the high-level functional descriptions of the ANSP model are described. Then, the implementations will be discussed. The ANSP programming model is based upon the interactions between four components: application client , application stub , capsule , and active service base.Figure 3. Information Flow with the ANSP.•Application Client : In a typical scenario, an active application requires some means to present information to its users, e.g., the state of the networks. A graphical user interface (GUI) is designed to operate with the application client if the ANSP runs on a non-active host.•Application Stub : When an application starts, it activates the application client to create a new instance of application stub at its near-by active node. There are two responsibilities for the application stub. One of them is to receive users’ instructions from the application client. Another one is to receive incoming capsules from networks and to perform appropriate actions. Typically, there are two types of actions, thatare, to reply or relay in capsules through the networks, or to notify the users regarding the incoming capsule. •Capsule : An active application may contain several capsule types. Each of them carries program code (also referred to as forwarding routine). Since the application defines a protocol to specify the interactions among capsules as well as the application stubs. Every capsule executes its forwarding routine at each router it visits along the path between the source and destination.•Active Service Base : An active service base is designed to export routers’ environments’ services and execute program calls from application stubs and capsules from different EEs. The base is loaded automatically at each router whenever a capsule arrives.The interactions among components within ANSP are shown in Figure 3. The designs of some key components in the ANSP will be discussed in the following subsections. A. Capsule (ANSPCapsule)ANSPXdr decode () ANSPXdr encode () int length ()Boolean execute ()New types of capsule are created by extending the abstract class ANSPCapsule . New extensions are required to define their own forwarding routines as well as their serialization procedures. These methods are indicated below:The execution of a capsule in ANSP is listed below. It is similar to the process in ANTS.1. A capsule is in serial binary representation before it issent to the network. When an active router receives a byte sequence, it invokes decode() to convert the sequence into a capsule. 2. The router invokes the forwarding routine of thecapsule, execute(). 3. When the capsule has finished its job and forwardsitself to its next hop by calling send(), this call implicitly invokes encode() to convert the capsule into a new serial byte representation. length() isused inside the call of encode() to determine the length of the resulting byte sequence. ANSP provides a XDR library called ANSPXdr to ease the jobs of encoding and decoding.B. Active Service Base (ANSPBase)In an active node, the Active Service Base provides a unified interface to export the available resources in EEs for the rest of the ANSP components. The services may include thread management, node query, and soft-store operation, as shown in Table 1.TABLE I. ACTIVE SERVICE BASE FUNCTION CALLSFunction Definition Descriptionboolean send (Capsule, Address) Transmit a capsule towards its destination using the routing table of theunderlying environment.ANSPAddress getLocalHost () Return address of the local host as an ANSPAddress structure. This isuseful when a capsule wants to check its current location.boolean isLocal (ANSPAddress) Return true if its input argument matches the local host’s address andreturn false otherwise.createThread () Create a new thread that is a class ofANSPThreadInterface (discussed later in Section VIA “Unified Thread Abstraction”).putSStore (key, Object) Object getSStore (key) removeSStore (key)The soft-store operations are provided by putSStore(), getSSTore(), and removeSStore(), and they put, retrieve, and remove data respectively. forName (PathName) Supported in ANSP to retrieve a classobject corresponding to the given path name in its argument. This code retrieval may rely on the code loading mechanism in the environment whennecessary.C. Application Client (ANSPClient)boolean start (args[])boolean start (args[],runningEEs) boolean start (args[],startClient)boolean start (args[],startClient, runningEE)Application Client is an interface between users and the nearby active source router. It does the following responsibilities.1. Code registration: It may be necessary to specify thelocation and name of the application code in some execution environments, e.g., ANTS. 2. Application initialization: It includes selecting anexecution environment to execute the application among those are available at the source router. Each active application can create an application client instance by extending the abstract class, ANSPClient . The extension inherits a method, start(), to automatically handle both the registration and initialization processes. All overloaded versions of start() accept a list of arguments, args , that are passed to the application stub during its initialization. An optional argument called runningEEs allows an application client to select a particular set of environment variables, specified by a list of standardized numerical environment ID, the ANEP ID, to perform code registration. If this argument is not specified, the default setting can only include ANTS and ASP. D. Application Stub (ANSPApplication)receive (ANSPCapsule)Application stubs reside at the source and destination routers to initialize the ANSP application after the application clients complete the initialization and registration processes. It is responsible for receiving and serving capsules from the networks as well as actions requested from the clients. A new instance is created by extending the application client abstract class, ANSPApplication . This extension includes the definition of a handling routine called receive(), which is invoked when a stub receives a new capsule.IV. ANSP E XAMPLE : T RACE -R OUTEA testbed has been created to verify the design correctnessof ANSP in heterogeneous environments. There are three types of router setting on this testbed:1. Router that contains ANTS and a ANSP daemonrunning on behalf of ASP; 2. Router that contains ASP and a ANSP daemon thatruns on behalf of ANTS; 3. Router that contains both ASP and ANTS.The prototype is written in Java [11] with a traceroute testing program. The program records the execution environments of all intermediate routers that it has visited between the source and destination. It also measures the RTT between them. Figure 4 shows the GUI from the application client, and it finds three execution environments along the path: ASP, ANTS, and ASP. The execution sequence of the traceroute program is shown in Figure 5.Figure 4. The GUI for the TRACEROUTE Program.The TraceCapsule program code is created byextending the ANSPCapsule abstract class. When execute() starts, it checks the Boolean value of returning to determine if it is returning from the destination. It is set to true if TraceCapsule is traveling back to the source router; otherwise it is false . When traveling towards the destination, TraceCapsule keeps track of the environments and addresses of the routers it has visited in two arrays, path and trace , respectively. When it arrives at a new router, it calls addHop() to append the router address and its environment to these two arrays. When it finally arrives at the destination, it sets returning to false and forwards itself back to the source by calling send().When it returns to source, it invokes deliverToApp() to deliver itself to the application stub that has been running at the source. TraceCapsule carries information in its data field through the networks by executing encode() and decode(), which encapsulates and de-capsulates its data using External Data Representation (XDR) respectively. The syntax of ANSP XDR follows the syntax of XDR library from ANTS. length() in TraceCapsule returns the data length, or it can be calculated by using the primitive types in the XDRlibrary.Figure 5. Flow of the TRACEROUTE Capsules.V. C ONCLUSIONSIn this paper, we present a new unified layered architecture for active networks. The new model is known as Active Network Socket Programming (ANSP). It allows each active application to be written once and run on multiple environments in active networks. Our experiments successfully verify the design of ANSP architecture, and it has been successfully deployed to work harmoniously with ANTS and ASP without making any changes to their architectures. In fact, the unified programming interface layer is light-weighted and can be dynamically deployable upon request.R EFERENCES[1] D.D. Clark, D.L. Tennenhouse, “Architectural Considerations for a NewGeneration of Protocols,” in Proc. ACM Sigcomm’90, pp.200-208, 1990. [2] D. Tennenhouse, J. M. Smith, W. D. Sicoskie, D. J. Wetherall, and G. J.Minden, “A survey of active network research,” IEEE Communications Magazine , pp. 80-86, Jan 1997.[3] D. Wetherall, U. Legedza, and J. Guttag, “Introducing new internetservices: Why and how,” IEEE Network Magazine, July/August 1998. [4] M. Fry, A. Ghosh, “Application Layer Active Networking,” in ComputerNetworks , Vol.31, No.7, pp.655-667, 1999.[5] K. W. Chin, “An Investigation into The Application of Active Networksto Mobile Computing Environments”, Curtin University of Technology, March 2000.[6] S. Bhattacharjee, K. L. Calvert, and E. W. Zegura, “Self OrganizingWide-Area Network Caches”, Proc. IEEE INFOCOM ’98, San Francisco, CA, 29 March-2 April 1998.[7] L. H. Leman, S. J. Garland, and D. L. Tennenhouse, “Active ReliableMulticast”, Proc. IEEE INFOCOM ’98, San Francisco, CA, 29 March-2 April 1998.[8] D. Descasper, G. Parulkar, B. Plattner, “A Scalable, High PerformanceActive Network Node”, In IEEE Network, January/February 1999.[9] E. L. Nygren, S. J. Garland, and M. F. Kaashoek, “PAN: a high-performance active network node supporting multiple mobile code system”, In the Proceedings of the 2nd IEEE Conference on Open Architectures and Network Programming (OpenArch ’99), March 1999. [10] D. L. Tennenhouse, and D. J. Wetherall. “Towards an Active NetworkArchitecture”, In Proceeding of Multimedia Computing and Networking , January 1996.[11] D. J. Wetherall, J. V. Guttag, D. L. Tennenhouse, “ANTS: A toolkit forBuilding and Dynamically Deploying Network Protocols”, Open Architectures and Network Programming, 1998 IEEE , 1998 , Page(s): 117 –129.[12] B. Braden, A. Cerpa, T. Faber, B. Lindell, G. Phillips, and J. Kann.“Introduction to the ASP Execution Environment”: /active-signal/ARP/index.html .[13] “The java language: A white paper,” Tech. Rep., Sun Microsystems,1998.。
采矿工程 毕业设计_外文翻译 英译汉 中英文
ROOM-AND-PILLAR METHOD OF OPEN-STOPE MINING空场采矿法中的房柱采矿法Chapter 1.A Classification of the Room-and-Pillar Method of Open-Stope Mining第一部分，空场采矿的房柱法的分类OPEN STOPING空场采矿法An open stope is an underground cavity from which the initial ore has been mined. Caving of the opening is prevented (at least temporarily) by support from the unmined ore or waste left in the stope,in the form of pillars,and the stope walls (also called ribs or abutments). In addition to this primary may also be required using rockbolts , reinforcing rods, split pipes ,or shotcrete to stabilize the rock surface immediately adjacent to the opening. The secondary reinforcement procedure does not preclude the method classified as open stoping.露天采场台阶是开采了地下矿石后形成的地下洞室。
通过块矿或采场的支柱和（也称为肋或肩）采场墙形式的废料的支持来（至少是暂时的）预防放顶煤的开幕。
除了这个，可能还需要使用锚杆，钢筋棒，分流管，或喷浆，以稳定紧邻开幕的岩石表面。
毕设翻译英文
轨道交通学院毕业设计（论文）外文翻译题目：列车车载的直流恒流源的设计专业电子信息工程班级10115111学号1011511137姓名赵士伟指导教师陈文2014 年3 月 3 日本文摘自：IEEE TRANSACTIONS ON INDUSTRY AND GENERAL APPLICATIONS VOL. IGA-2, NO.5 SEPT/OCT 1966Highly Regulated DC Power Supplies Abstract-The design and application of highly regulated dc power supplies present many subtle, diverse, and interesting problems. This paper discusses some of these problems (especially inconnection with medium power units) but emphasis has been placed more on circuit economics rather than on ultimate performance.Sophisticated methods and problems encountered in connection with precision reference supplies are therefore excluded. The problems discussed include the subjects of temperature coefficient,short-term drift, thermal drift, transient response degeneration caused by remote sensing, and switching preregualtor-type units and some of their performance characteristics.INTRODUCTIONANY SURVEY of the commercial de power supply field will uncover the fact that 0.01 percent regulated power supplies are standard types and can be obtained at relatively low costs. While most users of these power supplies do not require such high regulation, they never-theless get this at little extra cost for the simple reason that it costs the manufacturer very little to give him 0.01 percent instead of 0.1 percent. The performance of a power supply, however, includes other factors besides line and load regulation. This paper will discuss a few of these-namely, temperature coefficient, short-term drift, thermal drift, and transient response. Present medium power dc supplies commonly employ preregulation as a means of improving power/volume ratios and costs, but some characteristics of the power supply suffer by this approach. Some of the short-comings as well as advantages of this technology will be examined.TEMPERATURE COEFFICIENTA decade ago, most commercial power supplies were made to regulation specifications of 0.25 to 1 percent. The reference elements were gas diodes having temperature coefficients of the order of 0.01 percent [1]. Consequently, the TC (temperature coefficient) of the supply was small compared to the regulation specifications and often ignored. Today, the reference element often carries aTC specification greater than the regulation specification.While the latter may be improved considerably at little cost increase, this is not necessarily true of TC. Therefore,the use of very low TC zener diodes, matched differential amplifier stages, and low TC wire wound resistors must be analyzed carefully, if costs are to be kept low.A typical first amplifier stage is shown in Fig. 1. CRI is the reference zener diode and R, is the output adjustment potentiometer.Fig. 1. Input stage of power supply.Fig. 2. Equivalent circuit of zener reference.Let it be assumed that e3, the output of the stage, feedsadditional differential amplifiers, and under steady-state conditions e3 = 0. A variation of any of the parameters could cause the output to drift; while this is also true of the other stages, the effects are reduced by the gain of all previous stages. Consequently, the effects of other stages will be neglected. The following disculssion covers the effects of all elements having primary and secondary influences on the overall TC.Effect of R3The equivalent circuit of CRI -R3 branch is shown in Fig. 2. The zener ha's been replaced with its equivalent voltage source E/' and internal impedance R,. For high gain regulators, the input of the differential amplifier will have negligible change with variations of R3 so thatbefore and after a variation of R3 is made.If it is further assumed that IB << Iz; then from (1)Also,Eliminating I, from (2b),andNow, assuming thatthen,Equation (2b) can also be writtenThe Zener DiodeThe zener diode itself has a temperature coefficient andusually is the component that dominates the overall TCof the unit. For the circuit of Fig. 1, the TC ofthe circuit describes, in essence, the portion of the regulator TC contributed by the zener. If the bridge circuit shown in Fig. 1 were used in conjunction with a dropping resistor so that only a portion of the output voltage appeared across the bridge circuit shown, the TC of the unit and the zener would be different. Since the characteristic of zeners is so well known and so well described in the literature, a discussion will not be given here [2].Variation of Base-Emitter VoltagesNot only do the values of V,, of the differential am-plifier fail to match, but their differentials with tem perature also fail to match. This should not, however,suggest that matched pairs are required. The true reference voltage of Fig. 1 is not the value E,, but E, + (Vie, -Vbe2)-Since, for most practical applicatioinsthe TC of the reference will be the TC of the zener plusConsidering that it is difficult to obtain matched pairs that have differentials as poor as 50 V/°C, it becomes rather apparent that, in most cases, a matched pair bought specifically for TC may be overdesigning.Example 2: A standard available low-cost matched pair laims 30AV/°C. In conjunction with a 1N752, the ontribution to the overall TC would beTests, performed by the author on thirteen standard germanium signal transistors in the vicinity of room temperature and at a collector current level of 3 mA,indicated that it is reasonable to expect that 90 to 95 percent of the units would have a base-emitter voltage variation of -2.1 to -2.4 mV/°C. Spreads of this magnitude have also been verified by others (e.g., Steiger[3]). The worst matching of transistors led to less than 400 ,V/°C differential. In conjunction with a 1N752,even this would give a TC of better than 0.007%/0C.Variation of Base CurrentsThe base current of the transistors is given byA variation of this current causes a variation in signal voltage at the input to the differential amplifier due to finite source impedances. Matching source impedances is not particularly desirable, since it reduces the gain of the system and requires that transistors matched for I,o and A be used. Hunter [4 ] states that the TC of a is in the range of +0.2%/0C to -0.2%7/'C and that 1,, may be approximated bywhere Ao is the value at To.β is also temperature dependent and Steiger [3] experimentally determined the variation to be from about 0.5%/°C to 0.9%/0C.And，Fig. 3. Input circuit of Q2.The current AIB flows through the source impedance per Fig. 3. The drops in the resistance string, however, are subject to the constraint that EB (and AEB) are determined by the zener voltage and the base-emitter drops of Q1 and Q2. Consequently, if in going from temperature T1to T2 a change AEB occurs,The change in output voltage isAndExample 3: For Q2 (at 25°C)(see Example 1)∴Variation of R,The effects of a variation of the TC between RIA and RIB is sufficiently self-evident so that a discussion of the contribution is not included.SHORT-TERM DRIFTThe short-term drift of a supply is defined by the National Electrical Manufacturers Association (NEMA) as "a change in output over a period of time, which change is unrelated to input, environment, or load [5]."Much of the material described in the section on temperature coefficient is applicable here as well. It has been determined experimentally, however, that thermal air drafts in and near thevicinity ofthe powersupplycontributesenormouslyto theshort-termcharacteristics. Thecooling effects of moving air are quite well known, but it is not often recognized that even extremely slow air movements over such devices as zeners and transistors cause the junction temperature of these devices to change rapidly. If the TC of the supply is large compared to the regulation, then large variations in the output will be observed. Units having low TC's achieved by compensation-that is, by canceling out the effects of some omponents by equal and opposite effects of others may still be plagued by these drafts due to the difference in thermal time constants of the elements.Oftentimes, a matched transistor differential amplifier in a common envelope is used for the first amplifier just to equalize and eliminate the difference in cooling effects between the junctions. Approximations to this method include cementing or holding the transistors together, imbedding the transistors in a common metal block, etc. Excellent results were achieved by the author by placing the input stage and zener reference in a separate enclosure. This construction is shown in Fig. 4. The improvement in drift obtained by means of the addition of the metal cover is demonstrated dramatically in Fig. 5.Fig. 5. Short-term drift of a power supply similar to the one shown in Fig. 4 with and without protective covers. The unit was operated without the cover until time tl, when the cover was attached. The initial voltage change following t, is due to a temperaturerise inside the box.Fig. 5. Short-term drift of a power supply similar to the one shown n Fig. 4 withand without protective covers. The unit was operated without the cover until time tl, when the cover was attached. The initial voltage change following t, is due to atemperature rise inside the box.If potentiometers are used in the supply for output adjustment (e.g., RI), care should be used in choosing the value and design. Variations of the contact resistance can cause drift. It is not always necessary, however, to resort to the expense of high-resolution multiturn precision units to obtain low drift. A reduction in range of adjustment, use of low-resistance alloys and low-resolution units which permit the contact arm to rest firmly between turns, may be just as satisfactory. Of course, other considerations should include the ability of both the arms and the wire to resist corrosion. Silicone greases are helpful here. Periodic movement of contact arms has been found helpful in "healing" corroded elements.THERMAL DRIFTNEMA defines thermal drift as "a change in output over a period of time, due to changes in internal ambient temperatures not normally related to environmental changes. Thermal drift is usually associated with changes in line voltage and/or load changes [5]."Thermal drift, therefore, is strongly related to the TC of the supply as well as its overall thermal design. By proper placement of critical components it is possible to greatly reduce or even eliminate the effect entirely. It is not uncommon for supplies of the 0.01 percent(regulation) variety to have drifts of between 0.05 to 0.15 percent for full line or full load variations. In fact, one manufacturer has suggested that anything better than 0.15 percent is good. Solutions to reducing thermal drift other than the obvious approach of improving the TC and reducing internal losses include a mechanical design that sets up a physical and thermal barrier between the critical amplifier components and heat dissipating elements. Exposure to outside surfaces with good ventilation is recommended. With care, 0.01 to 0.05 percent is obtainable.TRANSIENT RESPONSEMost power supplies of the type being discussed have a capacitor across the load terminals. This is used for stabilization purposes and usually determines the dominant time constant of the supply. The presence of this capacitor unfortunately leads to undesirable transient phenomena when the supply is used in the remote sensing mode①. Normally, transistorized power supplies respond in microseconds, but as the author has pointed out [6], the response can degenerate severely in remote sensing .The equivalent circuit is shown in Fig. 6. The leads from the power supply to the load introduce resistance r. Is is the sensing current of the supply and is relatively constant.Under equilibrium conditions,A sudden load change will produce the transient of Fig. 7. The initial "spike" is caused by an inductive surge Ldi/dt; the longer linear discharge following is the resultof the capacitor trying to discharge (or charge). The discharge time iswhereandThe limitations of I,, are usually not due to available drive of the final amplifier stages but to other limitations, current limiting being the most common. Units using pre regulators of the switching type (transistor or SCR types) should be looked at carefully if the characteristics mentioned represent a problem.①Remote sensing is the process by which the power supply senses voltage directly at the load.Fig. 6. Output equivalent circuit at remote sensing.Fig. 7. Transient response, remote sensing.Fig. 8. Block diagram.Preregulated supplies are used to reduce size and losses by monitoring and controlling the voltage across the class-A-type series passing stage (Fig. 8). Since the main regulator invariably responds much quicker than the preregulator, sufficient reserve should always be built into the drop across the passing stage. Failure to provide this may result in saturation of the passing stage when load is applied, resulting in a response time which is that of the preregulator itself.SWITCHING PREREGULATOR-TYPE UNITS The conventional class-A-type transistorized power supply becomes rather bulky, expensive, and crowded with passing stages, as the current and power level of the supply increases. The requirement of wide output adjustment range, coupled with the ability of the supply to be remotely programmable, aggravates the condition enormously. For these reasons the high-efficiency switching regulator has been employed as a preregulator in commercial as well as military supplies for many years. The overwhelming majority of the supplies used silicon controlled rectifiers as the control element. For systems operating from 60-cycle sources, this preregulator responds in 20 to 50 ms.Recent improvements in high-voltage, high-power switching transistors has made the switching transistor pproach more attractive. This system offers a somewhat lower-cost, lower-volume approach coupled with a submillisecond response time. This is brought about by a high switching rate that is normally independent of line frequency. The switching frequency may be fixed, a controlled variable or an independent self-generated (by the LC filter circuit) parameter [7], [8]. Faster response time is highly desirable since it reduces the amount of reserve voltage required across the passing stage or the amount of (storage) capacity required in the preregulator filter.A transistor suitable for operating as a power switch has a high-current, high-voltage rating coupled with low leakage current. Unfortunately, these characteristics are achieved by a sacrifice in thermal capacity, so that simultaneous conditions of voltage and current leading to high peak power could be disastrous. It therefore becomes mandatory to design for sufficient switch drive during peak load conditions and also incorporate current-limiting or rapid overload protection systems.Commercial wide-range power supplies invariably have output current limiting, but this does not limit the preregulator currents except during steady-state load conditions (including short circuits). Consider, for example, a power supply operating at short circuit and the short being removed suddenly. Referring to Fig. 8, the output would rise rapidly, reduce the passing stage voltage, and close the switching transistor. The resulting transient extends over many cycles (switching rate) so that the inductance of the preregulator filter becomes totally inadequate to limit current flow. Therefore, the current will rise until steady state is resumed, circuit resistance causes limiting, or insufficient drive causes the switch to come out of saturation. The latter condition leads to switch failure.Other operating conditions that would produce similar transients include output voltage programming and initial turn-on of the supply. Momentary interruption of input power should also be a prime consideration.One solution to the problem is to limit the rate of change of voltage that can appear across the passing stage to a value that the preregulator can follow. This can be done conveniently by the addition of sufficient output capacitance. This capacitance inconjunction with the current limiting characteristic would produce a maximum rate of change ofwhereC0 = output capacity.Assuming that the preregulator follows this change and has a filter capacitor Cl, then the switch current isDuring power on, the preregulator reference voltage rise must also be limited. Taking this into account,whereER = passing stage voltageTl = time constant of reference supply.The use of SCR's to replace the transistors would be a marked improvement due to higher surge current ratings, but turning them off requires large energy sources. While the gate turn-off SCR seems to offer a good compromise to the overall problem, the severe limitations in current ratings presently restrict their use.REFERENCES[1] J. G. Truxal, Control Engineer's Handbook. New York: McGrawHill, 1958, pp. 11-19.[2] Motorola Zener Diode/Rectifier Handbook, 2nd ed. 1961.[3] W. Steiger, "A transistor temperature analysis and its applica-tion to differential amplifiers," IRE Trans. on Instrumentation,vol. 1-8, pp. 82-91, December 1959.[4] L. P. Hunter, Handbook of Semi-Conductor Electronics. NewYork: McGraw Hill, 1956, p. 13-3.[5] "Standards publication for regulated electronic dc powersupplies," (unpublished draft) Electronic Power Supply Group,Semi-Conductor Power Converter Section, NEMA.[6] P. Muchnick, "Remote sensing of transistorized power sup-plies," Electronic Products, September 1962.[7] R. D. Loucks, "Considerations in the design of switching typeregulators," Solid State Design, April 1963.[8] D. Hancock and B. Kurger, "High efficiency regulated powersupply utilizing high speed switching," presented at the AIEEWinter General Meeting, New York, N. Y., January 27-February 1, 1963.[9] R. D. Middlebrook, Differential Amplifiers. New York: Wiley,1963.[10] Sorensen Controlled Power Catalog and Handbook. Sorensen,Unit of Raytheon Company, South Norwalk, Conn.With the rapid development of electronic technology, application field of electronic system is more and more extensive, electronic equipment, there are more and more people work with electronic equipment, life is increasingly close relationship. Any electronic equipment are inseparable from reliable power supply for power requirements, they more and more is also high. Electronic equipment miniaturized and low cost in the power of light and thin, small and efficient for development direction. The traditional transistors series adjustment manostat is continuous control linear manostat. This traditional manostat technology more mature, and there has been a large number of integrated linear manostat module, has the stable performance is good, output ripple voltage small, reliable operation, etc. But usually need are bulky and heavy industrial frequency transformer and bulk and weight are big filter.In the 1950s, NASA to miniaturization, light weight as the goal, for a rocket carrying the switch power development. In almost half a century of development process, switch power because of its small volume, light weight, high efficiency, wide range, voltage advantages in electric, control, computer, and many other areas of electronic equipment has been widely used. In the 1980s, a computer is made up of all of switch power supply, the first complete computer power generation. Throughout the 1990s, switching power supply in electronics, electrical equipment, home appliances areas to be widely, switch power technology into the rapid development. In addition, large scale integrated circuit technology, and the rapid development of switch power supply with a qualitative leap, raised high frequency power products of, miniaturization, modular tide.Power switch tube, PWM controller and high-frequency transformer is an indispensable part of the switch power supply. The traditional switch power supply is normally made by using high frequency power switch tube division and the pins, such as using PWM integrated controller UC3842 + MOSFET is domestic small power switch power supply, the design method of a more popularity.Since the 1970s, emerged in many function complete integrated control circuit, switch power supply circuit increasingly simplified, working frequency enhances unceasingly, improving efficiency, and for power miniaturization provides the broad prospect. Three end off-line pulse width modulation monolithic integrated circuit TOP (Three switch Line) will Terminal Off with power switch MOSFET PWM controller one package together, has become the mainstream of switch power IC development. Adopt TOP switch IC design switch power, can make the circuit simplified, volume further narrowing, cost also is decreased obviouslyMonolithic switching power supply has the monolithic integrated, the minimalist peripheral circuit, best performance index, no work frequency transformer can constitute a significant advantage switching power supply, etc. American PI (with) company in Power in the mid 1990s first launched the new high frequency switching Power supply chip, known as the "top switch Power", with low cost, simple circuit, higher efficiency. The first generation of products launched in 1994 represented TOP100/200 series, the second generation product is the TOPSwitch - debuted in 1997 Ⅱ. The above products once appeared showed strong vitality and he greatly simplifies thedesign of 150W following switching power supply and the development of new products for the new job, also, high efficiency and low cost switch power supply promotion and popularization created good condition, which can be widely used in instrumentation, notebook computers, mobile phones, TV, VCD and DVD, perturbation VCR, mobile phone battery chargers, power amplifier and other fields, and form various miniaturization, density, on price can compete with the linear manostat AC/DC power transformation module.Switching power supply to integrated direction of future development will be the main trend, power density will more and more big, to process requirements will increasingly high. In semiconductor devices and magnetic materials, no new breakthrough technology progress before major might find it hard to achieve, technology innovation will focus on how to improve the efficiency and focus on reducing weight. Therefore, craft level will be in the position of power supply manufacturing higher in. In addition, the application of digital control IC is the future direction of the development of a switch power. This trust in DSP for speed and anti-interference technology unceasing enhancement. As for advanced control method, now the individual feels haven't seen practicability of the method appears particularly strong,perhaps with the popularity of digital control, and there are some new control theory into switching power supply.（1）The technology: with high frequency switching frequencies increase, switch converter volume also decrease, power density has also been boosted, dynamic response improved. Small power DC - DC converter switch frequency will rise to MHz. But as the switch frequency unceasing enhancement, switch components and passive components loss increases, high-frequency parasitic parameters and high-frequency EMI and so on the new issues will also be caused.（2）Soft switching technologies: in order to improve the efficiency ofnon-linearity of various soft switch, commutation technical application and hygiene, representative of soft switch technology is passive and active soft switch technology, mainly including zero voltage switch/zero current switch (ZVS/ZCS) resonance, quasi resonant, zero voltage/zero current pulse width modulation technology (ZVS/ZCS - PWM) and zero voltage transition/zero current transition pulse width modulation (PWM) ZVT/ZCT - technical, etc. By means of soft switch technology can effectively reduce switch loss and switch stress, help converter transformation efficiency （3）Power factor correction technology (IC simplifies PFC). At present mainly divided into IC simplifies PFC technology passive and active IC simplifies PFC technology using IC simplifies PFC technology two kinds big, IC simplifies PFC technology can improve AC - DC change device input power factor, reduce the harmonic pollution of power grid.（4）Modular technology. Modular technology can meet the needs of the distributed power system, enhance the system reliability.（5）Low output voltage technology. With the continuous development of semiconductor manufacturing technology, microprocessor and portable electronic devices work more and more low, this requires future DC - DC converter can provide low output voltage to adapt microprocessor and power supply requirement of portable electronic devicesPeople in switching power supply technical fields are edge developing related power electronics device, the side of frequency conversion technology, development of switch between mutual promotion push switch power supply with more than two year growth toward light, digital small, thin, low noise and high reliability, anti-interference direction. Switching powersupply can be divided into the AC/DC and DC/DC two kinds big, also have AC/AC DC/AC as inverter DC/DC converter is now realize modular, and design technology and production process at home and abroad, are mature and standardization, and has approved by users, but the AC/DC modular, because of its own characteristics in the process of making modular, meet more complex technology and craft manufacture problems. The following two types of switch power supply respectively on the structure and properties of this.Switching power supply is the development direction of high frequency, high reliability, low consumption, low noise, anti-jamming and modular. Because light switch power, small, thin key techniques are changed, so high overseas each big switch power supply manufacturer are devoted to the development of new high intelligent synchronous rectifier, especially the improvement of secondary devices of the device, and power loss of Zn ferrite (Mn) material? By increasing scientific and technological innovation, to enhance in high frequency and larger magnetic flux density (Bs) can get high magnetic under the miniaturization of, and capacitor is a key technology. SMT technology application makes switching power supply has made considerable progress, both sides in the circuitboard to ensure that decorate components of switch power supply light, small, thin. The high frequency switching power supply of the traditional PWM must innovate switch technology, to realize the ZCS ZVS, soft switch technology has becomethe mainstream of switch power supply technical, and greatly improve the efficiency of switch power. For high reliability index, America's switch power producers, reduce by lowering operating current measures such as junction temperature of the device, in order to reduce stress the reliability of products made greatly increased.Modularity is of the general development of switch power supply trend can be modular power component distributed power system, can be designed to N + 1 redundant system, and realize the capacity expansion parallel. According to switch power running large noise this one defect, if separate the pursuit of high frequency noise will increase its with the partial resonance, and transform circuit technology, high frequency can be realized in theory and can reduce the noise, but part of the practical application of resonant conversion technology still have a technical problem, so in this area still need to carry out a lot of work, in order to make the technology to practional utilization.Power electronic technology unceasing innovation, switch power supply industry has broad prospects for development. To speed up the development of switch power industry in China, we must walk speed of technological innovation road, combination with Chinese characteristics in the joint development path, for I the high-speed development of national economy to make the contribution. The basic principle and component functionAccording to the control principle of switch power to classification, we have the following 3 kinds of work mode:1) pulse width adjustment type, abbreviation Modulation PulseWidth pulse width Modulation (PWM) type, abbreviation for. Its main characteristic is fixed switching frequency, pulse width to adjust by changing voltage 390v, realize the purpose. Its core is the pulse width modulator. Switch cycle for designing filter circuit fixed provided convenience. However, its shortcomings is influenced by the power switch conduction time limit minimum of output voltage cannot be wide range regulation; In addition, the output will take dummy loads commonly (also called pre load), in order to prevent the drag elevated when output voltage. At present, most of the integrated switch power adopt PWM way.2) pulse frequency Modulation mode pulse frequency Modulation (, referred to PulseFrequency Modulation, abbreviation for PFM) type. Its characteristic is will pulse width fixed by changing switch frequency to adjust voltage 390v, realize the purpose. Its core is the pulse frequency modulator. Circuit design to use fixed pulse-width generator to replace the pulse width omdulatros and use sawtooth wave generator voltage? Frequency converter (for example VCO changes frequency VCO). It on voltage stability principle is: when the output voltage Uo rises, the output signal controller pulse width unchanged and cycle longer, make Uo 390v decreases, and reduction. PFM type of switch power supply output voltage range is very wide, output terminal don't meet dummy loads. PWM way and way of PFM respectively modulating waveform is shown in figure 1 (a), (b) shows, tp says pulse width (namely power switch tube conduction time tON), T represent cycle. It can be easy to see the difference between the two. But they have something in common: (1) all use time ratio control (TRC) on voltage stability principle, whether change tp, finally adjustment or T is。
毕设翻译原文
AIR DATA INSTRUMENTS OF B737 NG1. GENERAL DESCRIPTIONGeneralThe standby altimeter/airspeed indicator is two flight instruments in one component.One instrument is a pneumatic altimeter. It gets static air pressure from the alternate static ports and shows barometric altitude.The other instrument is a pneumatic airspeed indicator. This indicator gets pitot air pressure from the alternate pitot probe and static air pressure from the alternate static ports to show the indicated air speed.2.INTERFACEPowerThe vibrator in the standby altimeter/airspeed indicator gets 28v dc from the dc standby bus, through the CAPT ALT/AS VIBRATOR circuit breaker.The indicator gets 5v ac for the internal instrument lights from the master dim and test circuit.Pitot-Static InterfaceThe alternate pitot probe sends pitot air pressure to the standbyaltimeter/airspeed indicator. The alternate static ports send static air pressure to the indicator.3.STANDBY ALTIMETER/AIRSPEED INDICATORGeneralThe standby altimeter/airspeed indicator shows air data information such as barometric altitude and indicated airspeed. The standby altimeter/airspeed indicator receives pitot pressure from the alternate pitot probe. It also receives static pressure from the alternate static ports.OperationThe digital altitude display shows barometric altitude from -1000 to 50000 feet in thousands of feet. The altitude dial and pointer show altitude in 20 foot increments. One turn of the pointer is equal to 1000 feet.Barometric pressure reference in inches of mercury (in hg) and millibars (mb) shows on the indicator. Rotate the barometric reference control knob to set the barometric pressure reference. It is adjustable from 745 to 1049.5 mb and from 22.00 to 30.99 in hg.The zero adjust screw lets you adjust the altitude without changing the barometric reference settings. The digital airspeed display shows airspeeds from 60 to 450 knots. A drum, graduated in knots, shows the indicated airspeed.4、FUNCTIONAL DESCRIPTIONGeneralThe standby altimeter/airspeed indicator consists of these two pneumatic instruments:* Standby altimeter* Standby airspeed indicator.Standby AltimeterA vibrator is on the instrument frame to reduce friction errors in the mechanical linkage and to improve indicator response. The vibrator receives 28 volts dc power from the 28v dc standby bus. The standby altimeter gets static pressure from the two alternate static ports. The pressure sensor moves in response to the static pressure change. The sensor drives the altitude gear train which connects mechanically to the altitude counter and pointer. Rotating the BARO set knob on the front panel corrects for local changes in barometric pressure. Standby Airspeed IndicatorThe indicator mechanism has two pressure ports. One port is for static pressure and the other port is for pitot pressure. The pressure sensor expands and contracts with changes in the pitot-static pressure. The movement is transmitted to a counte r to indicate airspeed.5.ADJUSTMENT/TEST1. GeneralA. This procedure contains scheduled maintenance task data.B. This procedure has this task:(1) A system test of the Standby Altimeter/Airspeed Indicator.TASK 34-13-00-730-8012. Air Data Instruments - System TestA. General(1) These instructions apply to the task:(a) When you apply pressure to a static system, the rate must not be more than 5,000 feet foreach minute.(b) When you release pressure from a static system, the rate must not be more than 5,000 feetfor each minute.(c) When you apply pressure to a pitot system, the rate must not be more than 300 knots foreach minute.(d) When you release pressure from a pitot system, the rate must not be more than 300 knotsfor each minute.(e) Do not connect or disconnect the test equipment while you have pressure in the pitot-staticsystem.(f) Make sure that you do these steps before installing the probe adapter onthe probe:1) Flush the probe adapter with water.2) Use equal parts of water and ethylene glycol when the temperature is between 328F(08C) and -408F (-408C).3) Blow dry, filtered air through the adapter.4) Wipe the probe with a damp cloth.(g) Make sure that the seals used on the static ports do not extend into the static ports.(h) Make sure that you do not cause damage to the surface of the static ports when youremove the seals.(i) At each test value, permit the pressure to become stable for one minute. (j) Do not hit or shake the indicators before you read the values.B. ReferencesReference Title24-22-00-860-813 Supply External Power (P/B 201)24-22-00-860-814 Remove External Power (P/B 201)C. Tools/EquipmentNOTE: When more than one tool part number is listed under the same "Reference" number, thetools shown are alternates to each other within the same airplane series. Tool part numbersthat are replaced or non-procurable are preceded by "Opt:", which stands for Optional.D. Consumable MaterialsReference Description SpecificationG02219 Tape - Yellow Vinyl Adhesive, Scotch Brand No.471,1.5 Inches (38.1 mm) WideE. Location ZonesZone Area121 Forward Cargo Compartment - Left122 Forward Cargo Compartment - Right211 Flight Compartment - Left212 Flight Compartment - Right737-600/700/800/900AIRCRAFT MAINTENANCE MANUALEFFECTIVITYBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATOR34-13-00Page 502Jun 15/2014D633A101-BEJBOEING PROPRIETARY - Copyright# Unpublished Work - See title page for detailsF. Prepare for the System TestSUBTASK 34-13-00-860-011WARNING: MAKE SURE THAT THE ATC TRANSPONDERS ARE IN THE STANDBY MODE WHENYOU SIMULATE ALTITUDE. YOU CAN ACCIDENTALLY CAUSE TCAS TARGETS. AIRTRAFFIC IN THE AREA WILL CHANGE DIRECTION QUICKLY TO GO AWAY FROMTHESE TARGETS. THIS CAN CAUSE INJURIES TO PERSONNEL AND DAMAGE TOEQUIPMENT.(1) Make sure that the ATC transponders are in standby mode.SUBTASK 34-13-00-860-001BEJ 001-011(2) Open these circuit breakers and install safety tags:CAPT Electrical System Panel, P18-3Row Col Number NameC 2 C00238 HEATERS TEMP PROBED 3 C01071 HEATERS ALPHA VANE RIGHTD 5 C00525 HEATERS F/O PITOTD 6 C00524 HEATERS AUX PITOTF/O Electrical System Panel, P6-2Row Col Number NameA 6 C00566 FLIGHT CONTROL FLAP LOAD RELIEFBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-860-002(3) Do this task: Supply External Power, TASK 24-22-00-860-813.SUBTASK 34-13-00-750-001(4) Make sure that you feel vibration on the casing of the Standby Altimeter/Airspeed Indicator.SUBTASK 34-13-00-860-004(5) Set the BARO scale of the standby indicator to 29.92 inches of mercury (1013 millibars).SUBTASK 34-13-00-480-001CAUTION: DO NOT EXTEND THE SEALS INTO THE STATIC PORTS. DAMAGE TO THE SURFACEOF THE PORT CAN OCCUR WHEN YOU REMOVE THE SEAL.(6) Seal the alternate static ports with vinyl adhesive Scotch Brand No.471 tape, G02219 at theselocations:(a) The static port located at STA 430, WL 167, RBL 49.(b) The static port located at STA 430, WL 167, LBL 49.SUBTASK 34-13-00-480-003(7) Remove the cap from the alternate static drain located near STA 226, WL 155, RBL 18, in theelectronic equipment compartment below the E-5 rack.SUBTASK 34-13-00-480-007(8) Install the coupling, COM-1927, on the alternate static drain.SUBTASK 34-13-00-480-006(9) Connect the air data model test set, COM-1914, to the coupling, COM-1927.737-600/700/800/900AIRCRAFT MAINTENANCE MANUALEFFECTIVITYBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATOR34-13-00Page 503Jun 15/2013D633A101-BEJBOEING PROPRIETARY - Copyright# Unpublished Work - See title page for detailsSUBTASK 34-13-00-170-001BEJ 001-011CAUTION: FLUSH THE PITOT SYSTEM TEST ADAPTER WITH WATER BEFORE YOU ATTACH THEADAPTER TO THE PROBE. DAMAGE TO THE PROBE OR THE ADAPTER CAN OCCUR.(10) Flush the pitot test adapter, COM-1916, with water.(a) Use equal parts of water and ethylene glycol when the temperature is between 328F (08C)and -408F (-408C).BEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-480-008BEJ 001-011(11) Blow dry, filtered air through the pitot test adapter, COM-1916.BEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-480-009(12) Wipe the probe with a damp cloth.SUBTASK 34-13-00-480-004BEJ 001-011CAUTION: MAKE SURE THAT THE PITOT PROBE HAS NO ADDED WEIGHT ON IT FROM THE TESTHOSE. THE WEIGHT OF THE TEST HOSE CAN BEND OR TWIST THE PITOT PROBE OUTOF TOLERANCE.(13) Install the pitot test adapter, COM-1916, on the lower pitot probe located at STA 192, WL 213, RBL34.BEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-480-005BEJ 001-011(14) Connect the air data model test set, COM-1914, to the pitot test adapter, COM-1916.BEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-010-001(15) Lower the P5 forward overhead panel.(a) Loosen the 1/4-turn fasteners that hold the P5 forward overhead panel in position and letthe panel rotate downward.SUBTASK 34-13-00-020-001CAUTION: THE CABIN ALTITUDE DIFFERENTIAL PRESSURE INDICATOR MUST BEDISCONNECTED FROM ITS STATIC PRESSURE SOURCE AND THE SOURCE CAPPED.FAILURE TO DISCONNECT THE CABIN DIFFERENTIAL PRESSURE INDICATOR MAYRESULT IN DAMAGE TO THE INDICATOR.(16) Disconnect the alternate static hose from the cabin altitude differential pressure indicatorlocated behind the P5 forward overhead panel.737-600/700/800/900AIRCRAFT MAINTENANCE MANUALEFFECTIVITYBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATOR34-13-00Page 504Oct 15/2012D633A101-BEJBOEING PROPRIETARY - Copyright#Unpublished Work - See title page for detailsG. Air Data Instruments TestSUBTASK 34-13-00-860-005(1) Apply pressure to the alternate pitot and alternate static systems for eachtest point as shown in(Table 501):Table 501/34-13-00-993-801TEST POINT STATIC (In. Hg) PITOT (In. Hg) STBY ALT. (feet) STBY A/S (knots)1 29.921 30.311 0±30 90±3.52 24.896 27.996 5,000±50 250±3.53 16.886 17.703 15,000±110 130±3.54 11.104 17.013 25,000±160 340±85 7.041 10.963 35,000±210 279±66 5.286 7.95 41,000±235 233±6SUBTASK 34-13-00-730-001(2) Make sure that the altitude and airspeed information displayed on the standby altitude/airspeedindicator is in tolerance for each test point shown in Table 501.SUBTASK 34-13-00-210-002(3) APU shutdown is normal during the test.(a) Make sure that the message is reset.H. Put the Airplane Back to Its Usual ConditionSUBTASK 34-13-00-860-006(1) Put the system back to ambient pressure.SUBTASK 34-13-00-080-001CAUTION: DO NOT DISCONNECT THE PITOT SYSTEM TEST ADAPTER WHEN THE PITOT-STATICSYSTEM IS NOT AT AMBIENT PRESSURE. DAMAGE TO THE AIR DATA MODULESCAN OCCUR IF THE SYSTEM IS NOT AT AMBIENT PRESSURE.(2) Disconnect the air data model test set, COM-1914, and the coupling, COM-1927, from thealternate static drain located near STA 226, WL 155, RBL 18.SUBTASK 34-13-00-080-002(3) Install the cap on the alternate static drain.SUBTASK 34-13-00-080-003(4) Remove the vinyl adhesive Scotch Brand No.471 tape, G02219 from both of the alternate staticports.WARNING: MAKE SURE THAT ALL TAPE IS REMOVED FROM STATIC PORTS BEFOREFLIGHT. IF YOU DO NOT REMOVE THE TAPE, IT CAN CAUSE A MALFUNCTIONOF THE AIRCRAFT IN FLIGHT. THIS CAN KILL PERSONS AND CAN CAUSEDAMAGE TO THE AIRCRAFT.(a) Remove the vinyl adhesive Scotch Brand No.471 tape, G02219 from the static port locatedat STA 430, WL 167, RBL 49.(b) Remove the vinyl adhesive Scotch Brand No.471 tape, G02219 from the static port locatedat STA 430, WL 167, LBL 49.737-600/700/800/900AIRCRAFT MAINTENANCE MANUALEFFECTIVITYBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATOR34-13-00Page 505Oct 15/2012D633A101-BEJBOEING PROPRIETARY - Copyright# Unpublished Work - See title page for detailsSUBTASK 34-13-00-080-004BEJ 001-011CAUTION: DO NOT DISCONNECT THE PITOT SYSTEM TEST ADAPTER WHEN THE PITOT-STATICSYSTEM IS NOT AT AMBIENT PRESSURE. DAMAGE TO THE AIR DATA MODULESCAN OCCUR IF THE SYSTEM IS NOT AT AMBIENT PRESSURE.(5) Disconnect the air data model test set, COM-1914, from the pitot test adapter, COM-1916.BEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-080-005BEJ 001-011(6) Remove the pitot test adapter, COM-1916, from the pitot probe.BEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-410-001(7) Connect the alternate static hose to the cabin altitude differential pressure indicator locatedbehind the P5 forward overhead panel.SUBTASK 34-13-00-210-001(8) Do a visual inspection of the quick-disconnect fittings that you connected.(a) Make sure that the actuation ring of the quick-disconnect fitting is fully engaged on the lockpins, and make sure that you see the colored lock ring indicator that shows a correctconnection of the quick-disconnect fitting.SUBTASK 34-13-00-410-002(9) Lift the P5 forward overhead panel to the closed position and turn the1/4-turn fasteners.SUBTASK 34-13-00-860-007BEJ 001-011(10) Remove the safety tags and close these circuit breakers:CAPT Electrical System Panel, P18-3Row Col Number NameC 2 C00238 HEATERS TEMP PROBED 3 C01071 HEATERS ALPHA VANE RIGHTD 5 C00525 HEATERS F/O PITOTD 6 C00524 HEATERS AUX PITOTF/O Electrical System Panel, P6-2Row Col Number NameA 6 C00566 FLIGHT CONTROL FLAP LOAD RELIEFBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATORSUBTASK 34-13-00-860-008(11) Do this task: Remove External Power, TASK 24-22-00-860-814.------------------------- END OF TASK ---------------------------737-600/700/800/900AIRCRAFT MAINTENANCE MANUALEFFECTIVITYBEJ 001-011; AIRPLANES WITH THE STANDBY ALTITUDE/AIRSPEED INDICATOR34-13-0。
毕 业 设 计(英文翻译)
毕业设计（英文翻译）译文内容ERP project implementation experiences and lessons （ERP项目实施经验和教训）译文出处IT Professional系别：信息管理系专业：信息管理与信息系统班级：T873-1学生姓名：曹凯学号：20080730126指导教师：蔡亮ERP project implementation experiences and lessons The past one or two years, around the ERP of many articles, covering almost every corner of the ERP, which greatly promoted the concept of ERP in China to promote. Although different authors differences of opinion, but at least there is one thing that all authors agree that successful application of ERP system depends on three aspects, the phenomenon can be expressed with the following formula: ERP Application Success = prepared suitable software companies among the successful implementation of the successful implementation of ERP systems applications to ensure the success of the most important factor. A lot of preparations for the implementation or are being implemented ERP enterprise ERP implementation methods and models for a clear understanding of, often to the implementation of unnecessary trouble. This chapter, we will focus on ERP implementation of the project to resolve the various problems for users reference. ERP software and general financial software or small software applications, the biggest difference is the "implement" this idea. The general financial software, or other small applications, as long as software developers or distributors slight training for users, a user can operate the software, software application effect good or bad depends largely on the quality of the software itself, ERP system is very different from so-called " one-third of software, seven parts to implement. "ERP Software Project "implemented" (Implementation) this concept can be present in our country is not yet widely accepted in society. Company also believes that spend money on custom software, software developers will have responsibility for the software free of charge to help companies use them does not know the need for a standardized ERP software, the "implementation" process, this process is time-consuming, human consumption, but also Enterprise implementation costs paid separately. ERP software for project "implementation of the" understanding of the concept should include the following aspects: the implementation of business management software is very difficult, the need for implementation of the methodology guidance, the need for a professional team specializing in software implementation, the need for software programming standardized training materials.Enterprise management software project software is not just hands-on training for users, more importantly, enterprises should first business process reengineering (Reengineering), rationalize and standardize the enterprise management. This is a business management software implementation of an important step.Enterprise management software project is not only guide the user how to use the software, but also to help the user information standardization and standardized codes.Business management software for project implementation will require not only enterprise software provides the standard management model, also called for in the implementation process can also be handled according to the user's specific business needs of the software for customer-oriented transformation.Enterprise management software, project implementation is a time-consuming process of human and financial resources to implement short cycle is six months or as long as two to four years. And software implementation costs, the price varies from quite as many as several times to achieve software, the purchase price.ERP software implementation of the project is to change and optimize business processes as a catalyst. The entire software implementation process requires the adjustment of business processes and re-design and application software functionality tightly together, simultaneously. Which pairs of business management will be produced by the impact could include: changes to the competitive strategy, organizational adjustments and departments to redefine the responsibilities of each individual job responsibilities and working methods and changes. These changes will be more conducive to enterprise business goals, but also for each employee, including all management and operational personnel challenges, corporate decision-making ability to understand and accept this concept critical to the success of software implementation.ERP project failureAt present, enterprises in the implementation of ERP systems, the main reason for project failure according to participate in the implementation of the main points, main reasons for enterprises and implementation of units of reasons.First, the reasons for enterprises1, weak basic data to establish the basis for enterprise data is an important measure for improving the management of the new system implementation is built on a sound basis for the data above. In the present circumstances the establishment of such data systems are also part of the implementation; different enterprises in this area has a large difference in the implementation side when doing demand analysis does not consider the difference;2, human factors, employees for the new system, accept the need for a psychological process of identification and operational proficiency. If the new system, greatly increase the use of their work, they produced a strong resistance to the implementation problems encountered in the process is magnified. In the ERP implementation process in the initial phase of increased workload seems to have become an unavoidable issue. In addition the new management style for the quality of personnel made a higher demand, causing some people's jobs crisis; the new management style will be committing some people's vested interests. In this case, if business leaders did not express a firm attitude, these people will adopt the attitude of defamation so that projects do not go. That is why many people call to ERP implementation into an number one reason for the project.3, issue management processes, poor strongest appeals of various articles and proposed "business process reengineering is a prerequisite for ERP implementation", but how no one gives a specific method of restructuring.4, for the implementation of objectives to be achieved without clear that the enterprise for the new system is not familiar, can learn from the successful experience and few would like to make a very clear objective very difficult. Therefore, to go to the function as possible, in this thought under the guidance of a choice, making the implementation of a number of parties will not sure, or even can not promise to do things down, for future implementation of the left barrier. Many companies on the implementation of ERP systems lack the right expectations that the ERP system is a "panacea" that can solve all the problems existence of the business, or to see other companies have implemented an ERP system indiscriminate competition;5, the basis of a large amount of data during the period in the implementation of some companies trying to one-time completion of these work, in fact it is not realistic. Butthere are also the other extreme, the only software process idle up, what data needs to work Adds what, it will have two questions there is no sense of many of the implementation of the basic data can not be put this work into the future of the Who do? Second, the new system to increase the use of workload, for example in the case of the data produced a complete work orders for five minutes to complete the contrary, the establishment of a single pre-work was to prepare a work plan, may take five hours. While you can use "In the future do this work on the simple" words of comfort, but its implementation is the negative impact of imagined.6, hoping to get a ready-made "products" from the enterprise point of view, the maintenance of normal production conditions, a long time to carry out a large-scale "management reform" is unrealistic, and hope to get a can brought on the word " products ", which is understandable. However, the basic data set, the software used must be the hands of employees to complete, the software implementation, after all, is different from a product application. Some users even too much to the current process evaluation system for the commercialization of ERP software, made too many unrealistic customized modifications.7, human input is not enough this is also emphasized in many articles the reasons for the introduction of advanced management methods first used by the enterprise backbone, but the "backbone" of the meaning of the production means that they are inseparable. Therefore, enterprises are also faced with the dilemma of choice, do not deploy the backbone of the implementation is difficult, but the backbone of a long out of production is indeed difficult. Implementation of the project the involvement of senior management personnel is not enough, the project team members and technical personnel-based, rather than related to the management and operational personnel; the main consideration of technology rather than the management of the applicability of applicability; only focused on ERP system may bring about the effectiveness of the implementation of ERP system, while ignoring the risks. This is also the inadequacy of human input.Second, the reasons for the implementation of unitThe basis of modern management in China rather weak, and its development can quickly give a catch up feel. Implementation of the personnel is always in a constantprocess of learning, there is no experience can learn much mature. Because the system is not very familiar with the implementation of achievable objectives are unclear, it is generally applied in the past the old MIS development will be implemented to treat the project as a development project, making the work done a lot but do not see results; not to the implementation of projects as a management approach, which is the implementation of units from the composition, as well as the content of technology exchange seminar can be reflected; implementation of the objectives of the uncertainty makes the results of the implementation depends entirely on the specific personal qualities and His understanding of the project. In other words, not only failed to reflect the implementation of device management software, management style, and even failed to reflect the implementation of units of management thinking, but is entirely personal style, which is with the software supplier could not provide detailed implementation guidance is directly related to . The implementation of team instability: This is China's software industry, a common problem. Implementation if it can be completed within the expected time, but also will not have much impact, but dragged on for far too long on the implementation team is a test, because of the implementation methods are not standardized, and personnel movement of the work done by a very easy out of touch. A B unequal relationship: the contract signing before the song is intended to meet the various requirements of Party A, even though there is suspicion of fraud, but the last resort of the larger components, contract enforcement in the Party's request to mention the more more Vietnam to mention the more detailed, until the last can not be met, the two sides stalled. Implementation of the ERP system has yet to learn to professional consultants bring tremendous value and help. For work abroad in the implementation of both management consulting firm, provides businesses with the implementation of programs, while the lack of corresponding organizations in the country, if any, have a high asking price for the enterprise is difficult to accept. ERP in domestic practice, this part of the work actually undertaken by the implementing units. Enterprises to implement ERP system is the benefits and risks coexist. Only a correct understanding of risk, control risk, thereby reducing the risk to successful implementation of ERP systems, ERP systems to fully enjoy the tremendous business benefits.The necessary conditions for the successful implementation of ERP'sERP enterprises should pay attention to the preconditions is that companies must understand the ERP, the demand for ERP systems to be very clear. Know what is ERP, know that ERP can solve any problem, to know that companies are most concerned about issues can be resolved with the ERP and know how to use ERP, and how to implement to be successful.First, a necessary condition for the successful implementation of ERP:To achieve information integration under certain conditions, the gist is to manage the basic specification. This is the implementation of the ERP system, a necessary condition. However, in order to be successful, there are many other factors, from the domestic implementation of experiences and lessons divided into pre-conditions and the correct implementation of two parts, are summarized as follows. Successful business must have seven pre-conditions, which must be made before the implementation of the system, estimates and judgments:1, enterprises have long-term business strategy, the product viable, sustainable and stable market share, there is a stable operating environment;2, there is the reform of leadership development, continuously enterprising spirit, the determination of the success or failure of project implementation responsibility;3, business in which competition in the market environment is key to the whole, there is a mechanism to achieve a modern enterprise system;4, the management of solid footing, data integrity;5, the leadership understands ERP, the building of a clear demand for ERP systems, there is the goal of reunification. Is the enterprise really feel the pressure of market competition: There is a sense of urgency and crisis. This switched from project managers League6, there is a clear realistic goals. To understand the ERP's basis, after a demonstration after the company's leadership to arrive at a unified aim, to all employees are aware of this goal, to achieve this goal.7, the leadership's determination and commitment: real ERP is essentially a management model change, which inevitably involves the "new ideas and changemanagement" and "update our concepts and change management" there is no business of the firm determination of senior leaders and specific guidance is not enough The.To be successful, the implementation process in the system, it is also important to note 9 to achieve the following:1, the project implementing organization candidates properly, there is effective leadership and hard work of project managers;2, emphasis on training, education, the importance of improving staff quality; Alliance project manager, project management issues.3, the manager act in harmony with the computer staff;4, attach importance to the accuracy and integrity of data;5, choose the applicable software, and long-term cooperation between software vendors;6, using the scientific project management, implementation methods, the implementation of proper guidance and technical service support;7, there is a strict work discipline, the work has developed strict protocols and guidelines;8, deepening reform, emphasis on business process reengineering;9, incentive mechanism, there is a stable compound personnel.Second, the implementation of ERP should be noted that solved the problem: Implementation of the ERP should be noted that there are many problems solved. Require special attention, which is most likely to be neglected or ignored. Mainly in the following 4 points.1, in which a candidate, and organizational issues. Job was to get people to do, and the specific implementation by the Implementation Group responsible for completing, therefore, the project should be properly implementing the organization's candidates. In particular, the project manager candidate, a direct bearing on project implementation success or failure.2, is training. Emphasis on training and education and improve the overall quality. Should pay attention to information technology and advanced management thought combination.3, is a good simulation to run.4, is conducive to accurate data to establish an incentive mechanism. The above 4 points are all about people, so management of people-oriented, good people is the most important.Implementation of the ERP system, the model approachSum up for many years in the global and domestic implementation of ERP systems experience, we believe that: ERP software, a prerequisite for the successful implementation is correct guiding ideology. Successful implementation of software is appropriate and effective role in the implementation of ways to share results. Model of success are: ERP system should be included in management thinking and in-depth and accurate understanding of this enterprise problems and managing change in thinking to be very clear, companies must understand their own management system, the expected new management system has to be a clear description. To establish the ability to accurately understand and implement changes in corporate management ideas, Jidong management software, but also understands and has experience in ERP system implementation, understanding the implementation of the law of system implementation team. In this team, there should be the highest policy level of personal involvement of business and leadership. For the changing needs of business management, business management options available to meet the appropriate changes in the software and hardware for implementation in an effective manner.Effective implementation include the following(1) Senior management commitment: the implementation of ERP system - must be senior management commitment to the project. Give the project sufficient attention, executive first, the second in command must participate in Project Steering Committeeand participate in project management, leadership project implementation process for major regulatory changes and business process assessment and decision making.(2) a practical project plan and budget.(3) a valid authorization, and human resources in a reasonable arrangement.(4) Sector Manager, directly involved in the project's success also has a very important role in the implementation of the project, each module will be the possibility of successful implementation of the relevant departments of the relevant department managers as a key assessment indicators, the participating departments by the department manager within the business process reengineering.(5) mutual cooperation between the various departments.(6) personnel education and training.(7) the formation of a Jidong management team are also proficient in the implementation of software in this contingent, we must explicitly manage the implementation of Mei-chin, the core of top management by one or number two personally led the daily work should be from led by representatives of top management, IT departments in the project team could only serve to provide technical support and software maintenance role.(8) implemented in phases in order to point to an area to demonstrate effect of allowing the system end-users and business managers to implement as soon as possible to see results. Not only with the lack of knowledge of ERP software, but also has practical industry knowledge and management experience, proficient in the law of ERP system implementation and project management expertise, and can guide enterprises in the successful implementation of ERP business management while achieving changes in personnel, is the enterprise in the implementation of ERP systems have to face the most practical problems in implementing the strategy million in hand, successful companies to choose a qualified professional with considerable consulting firm to assist the implementation of ERP systems. In other countries, choose a professional consulting firm is not necessarily the selected ERP software company. Alliance project manager articles in depth.ERP system implementation process is to develop a standardized model, which is thousands of enterprises at home and abroad for many years into practice, summed upthe experience, in accordance with the principles of project management, followed by the following main components:The establishment of three project organizations; to develop an implementation plan; overall demand survey, the overall solution and detailed solution design; right personnel at different levels of continuous and repeated training; to prepare and input data; software features simulation run (prototype testing); customization and secondary development; to simulate the actual operation, demonstration, evaluation, revision, approval; the development of new guidelines for the work systems and work procedures; from a small number of government departments started to switch to the new system, and gradually expand the scope of application; summary evaluation, continuous improvement.ERP项目实施经验和教训在过去的一两年中，各地有很多文章，几乎涵盖了所有关于ERP的，这大大促进了ERP在中国的概念，ERP软件。
有关零售超市毕业设计外文翻译
有关零售超市毕业设计外文翻译毕业设计（论文）外文翻译题目对零售超市数据进行最优产品选择的数据挖掘框架：广义PROFSET模型专业网络工程附录英文原文A Data Mining Framework for OptimalProduct Selection in Retail Supermarket Data:The Generalized PROFSET Model1 IntroductionSince almost all mid to large size retailers today possess electronic sales transaction Systems, retailers realize that competitive advantage will no longer be achieved by the mere use of these systems for purposes of inventory management or facilitating customer check-out. In contrast, competitive advantage will be gained by those retailers who are able to extract the knowledge hidden in the data, generated by those systems, and use it to optimize their marketing decision making. In this context, knowledge about how customers are using the retail store is of critical importance and distinctive competencies will be built by those retailers who best succeed in extracting actionable knowledge from these1data. Association rule mining [2] can help retailers to efficiently extract this knowledge from large retail databases. We assume some familiarity with the basic notions of association rule mining.In recent years, a lot of effort in the area of retail market basket analysis has been invested in the development of techniques to increase the interestingness of association rules. Currently, in essence three different research tracks to study the interestingness of association rules can be distinguished. First, a number of objective measures of interestingness have been developed in order to filter out non-interesting association rules based on a number of statistical properties of the rules, such as support and confidence [2], interest [14], intensity of implication [7], J-measure [15], and correlation [12]. Other measures are based on the syntactical properties of the rules [11], or they are used to discover the least-redundant set of rules [4]. Second, it was recognized that domain knowledge may also play an important role in determining the interestingness of association rules. Therefore, a number of subjective measures2of interestingness have been put forward, such as unexpectedness [13], action ability [1] and rule templates [10]. Finally, the most recent stream of research advocates the evaluation of the interestingness of associations in the light of themicro-economic framework of the retailer [9]. More specifically, a pattern in the data is considered interesting only to the extent in which it can be used in the decision-making process of the enterprise to increase its utility.It is in this latter stream of research that the authors have previously developed a model for product selection called PROFSET [3], that takes into account both quantitative and qualitative elements of retail domain knowledge in order to determine the set of products that yields maximum cross-selling profits. The key idea of the model is that products should not be selected based on their individual profitability, but rather on the total profitability that they generate, including profits from cross-selling. However, in its previous form, one major drawback of the model was its inability to deal with3supermarket data (i.e., large baskets). To overcome this limitation, in this paper we will propose an important generalization of the existing PROFSET model that will effectively deal with large baskets. Furthermore, we generalize the model to include category management principles specified by the retailer in order to make the output of the model even more realistic. The remainder of the paper is organized as follows. In Section 2 we will focus on the limitations of the previous PROFSET model for product selection. In Section 3, we will introduce the generalized PROFSET model. Section 4 will be devoted to the empirical implementation of the model and its results on real-world supermarket data. Finally, Section 5 will be reserved for conclusions and further research.2 The PROFSET ModelThe key idea of the PROFSET model is that when evaluating the business value of a product, one should not only look at the individual profits generated by that product (the naive approach), but one must also4take into account the profits due tocross-selling effects with other products in the assortment. Therefore, to evaluate product profitability, it is essential to look at frequent sets rather than at individual product items since the former represent frequently co-occurring product combinations in the market baskets of the customer. As was also stressed by Cabena et al. [5], one disadvantage of associations discovery is that there is no provision for taking into account the business value of an association. The PROFSET model was a first attempt to solve this problem. Indeed, in terms of the associations discovered, the sale of an expensive bottle of wine with oysters accounts for as much as the sale of a carton of milk with cereal. This example illustrates that, when evaluating the interestingness of associations, themicro-economic framework of the retailer should be incorporated. PROFSET was developed to maximize cross-selling opportunities by evaluating the profit margin generated per frequent set of products, rather than per product. In the next Section we will discuss the limitations5of the previous PROFSET model. More details can be found elsewhere [3].2.1 LimitationsThe previous PROFSET model was specifically developed for market basket data from automated convenience stores. Data sets of this origin are characterized by small market baskets (size 2 or 3) because customers typically do not purchase many items during a single shopping visit. Therefore, the profit margin generated per frequent purchase combination (X) could accurately be approximated by adding the profit margins of the market baskets (Tj) containing the same set of items, i.e. X = Tj. However, for supermarket data, the existing formulation of the PROFSET model poses significant problems since the size of market baskets typically exceeds the size of frequent item sets. Indeed, in supermarket data, frequent item sets mostly do not contain more than 7 different products, whereas the size of the average market basket is typically 10 to 15. As a result, the existing profit allocation heuristic cannot be used anymore since it would cause the6model to heavily underestimate the profit potential from cross-selling effects between products. However, getting rid of this heuristic is not trivial and it will be discussed in detail in Section 3.1.A second limitation of the existing PROFSET model relates to principles of category management. Indeed, there is an increasing trend in retailing to manage product categories as separate strategic business units [6]. In other words, because of the trend to offer more products, retailers can no longer evaluate and manage each product individually. Instead, they define product categories and define marketing actions (such as promotions or store layout) on the level of these categories. The generalized PROFSET model takes this domain knowledge into account and therefore offers the retailer the ability to specify product categories and place restrictions on them.3 The Generalized PROFSET ModelIn this section, we will highlight the improvements being made to the previous7PROFSET model [3].3.1 Profit AllocationAvoiding the equality constraint X = Tj results in different possible profit allocation systems. Indeed, it is important to recognize that the margin of transaction Tj can potentially be allocated to different frequent subsets of that transaction. In other words, how should the margin m (Tj) be allocated to one or more different frequent subsets of Tj?The idea here is that we would like to know the purchase intentions of the customer who bought Tj . Unfortunately, since the customer has already left the store, we do not possess this information. However, if we can assume that some items occur more frequently together than others because they are considered complementary by customers, then frequent item sets may be interpreted as purchase intentions of customers. Consequently, there is the additional problem of finding out which and how many purchase intentions are represented in a particular transaction Tj . Indeed, a transaction may contain several8frequent subsets of different sizes, so it is not straightforward to determine which frequent sets represent the underlying purchase intentions of the customer at the time of shopping. Before proposing a solution to this problem, we will first define the concept of a maximal frequent subset of a transaction.Definition 1. Let F be the collection of all frequent subsets of a sales transaction Tj . Then YX∈is called maximal, denoted as X max , if and only if.F∀: Y X≤.Y∈Using this definition, we will adopt the following rationale to allocate the margin m(Tj) of a sales transaction Tj .If there exists a frequent set X = Tj, then we allocate m(Tj) to M(X), just as in the previous PROFSET model. However, if there is no such frequent set, then one maximal frequent subset X will be drawn from all maximal frequent subsets according to the probability distribution Tjθ, withAfter this, the margin m(X) is assigned toM(X) and the process is repeated for Tj \ X. In summary:Table 1 contains all frequent subsets of T for a particular transaction database. Inthis example, there is no unique maximal frequent subset of T. Indeed, there are two maximal frequent subsets of T, namely {cola, peanuts} and {peanuts, cheese}. Consequently, it is not obvious to which maximal frequent subset the profit margin m(T) should be allocated. Moreover, we would not allocate the entire profit margin m(T) to the selected item set, but rather the proportion m(X) that corresponds to the items contained in the selected maximal subset.Now how can one determine to which of both frequent subsets of T this marginshould be allocated? As we have already discussed, the crucial idea here is that it really depends on what has been the purchase intentions of the customer who purchased T. Unfortunately, one can never know exactly since we haven't asked the customer at the time of purchase. However, the support of the frequent subsets of T may provide some probabilistic estimation. Indeed, if the support of a frequent subset is an indicator for the probability of occurrence of this purchase combination, then according to the data, customers buy the maximal subset {cola, peanuts} two times more frequently than the maximal subset {peanuts, cheese}. Consequently, we can say that it is more likely that the customer's purchase intention has been {cola, peanuts} instead of {peanuts, cheese}. This information is used to construct the probability distribution Tjθ, reflecting the relative frequencies of the frequent subsets of T. Now, each time a sales transaction {cola, peanuts, cheese} is encountered in the data, a random draw from the probability distribution Tjθwill provide the most probable purchase intention (i.e. frequentsubset) for that transaction. Consequently, on average in two of the three times this transaction is encountered, maximal subset {cola, peanuts} will be selected and m({cola; peanuts}) will be allocated to M({cola; peanuts}). After this, T is split up as follows: T := T \{cola; peanuts}and the process of assigning the remaining margin is repeated as if the new T were a separate transaction, until T does not contain a frequent set anymore.3.2 Category Management RestrictionsAs pointed out in Section 2.1, a second limitation of the previous PROFSET model is its inability to include category management restrictions. This sometimes causes the model to exclude even all products from one or more categories because they do not contribute enough to the overall profitability of the optimal set. This often contradicts with the mission of retailers to offer customers a wide range of products, even if some of those categories or products are not profitable enough. Indeed, customers expect supermarkets to carry a wide variety of products and cutting away categories / departments would be against the customers' expectations about the supermarket and would harm the store's image. Therefore, we want to offer the retailer the ability to include category restrictions into the generalized PROFSET model.This can be accomplished by adding an additional index k to theQ to account for category membership, and by adding product variableiconstraints on the category level. Several kinds of category restrictions can be introduced: which and how many categories should be included in the optimal set, or how many products from each category should be included. The relevance of these restrictions can be illustrated by the following common practices in retailing. First, when composing a promotion leaflet, there is only limited space to display products and therefore it is important to optimize the product composition in order to maximize cross-selling effects between products and avoid product cannibalization. Moreover, according to the particular retail environment, the retailer will include or exclude specific products or product categories in the leaflet. For example, the supermarket in this study attempts to differentiate from the competition by the following image components: fresh, profitable and friendly. Therefore, the promotion leaflet of the retailer emphasizes product categories that support this image, such as fresh vegetables and meat, freshly-baked bread, ready-made meals, and others. Second, product category constraints may reflect shelf space allocations to products. For instance, large categories have more product facings than smaller categories. These kind of constraints can easily be included in the generalized PROFSET model as will be discussed hereafter.中文翻译对零售超市数据进行最优产品选择的数据挖掘框架：广义PROFSET模型第一章引言当今几乎所有的中大型零售商拥有电子销售交易系统，零售商认识到，竞争优势将不再仅仅取决于使用这些系统管理目的的库存或便利客户退房。
毕 业 设 计(英文翻译)
附录G：英文翻译参考（要求学生完成与论文有关的外文资料中文字数5000字左右的英译汉，旨在培养学生利用外文资料开展研究工作的能力，为所选课题提供前沿参考资料。
）毕业设计（英文翻译）题目系别：专业：班级：学生姓名：学号：指导教师：一位从事质量管理的人约瑟夫·朱兰出生于圣诞夜,1904 在罗马尼亚的喀尔巴阡山脉山中。
他青年时期的村庄中贫穷、迷信和反犹太主义甚是猖獗。
1912年朱兰家搬到了明尼阿波尼斯州，虽然充满了危险，但是它却让一个男孩充满信心和希望。
从如此多了一个在质量观念的世界最好改革者之一。
在他90年的生活中，朱兰一直是一个精力充沛的思想者倡导者，推动着传统的质量思想向前走。
因为九岁就被雇用,朱兰表示在他的生活工作上永不停止。
记者:技术方面如何讲质量?朱兰:技术有不同方面:一、当然是精密。
物的对精密的需求像电子学、化学…我们看来它们似乎需要放大来说,和重要的原子尘的有关于质量。
要做到高精密具有相当大的挑战，而且我们已经遇见非常大的挑战。
另外的一个方面是可信度－没有失败。
当我们举例来说建立一个系统，同类空中交通管制的时候,我们不想要它失败。
我们必须把可信度建入系统。
因为我们投入很大的资金并依赖这些系统，系统非常复杂，这是逐渐增加的。
除此之外,有对公司的失败费用。
如果事物在领域中意外失败,可以说，它影响民众。
但是如果他们失败在内部,然后它影响公司的费用,而且已经试着发现这些费用在哪里和该如何免除他们。
因此那些是相当大的因素:精密、可信度和费用。
还有其它的,当然，但是我认为这些是主要的一些。
记者:据说是质量有在美国变成一种产业的可能?朱兰:资讯科技当然有。
已经有大的变化。
在世纪中初期当质量的一个想法到一个检验部门的时候，这有了分开的工作，东西被做坏之后。
检验是相当易错的程序,实际上。
而且无论如何，资讯科技在那天中相当花时间，直到某事已经被认为是否资讯科技是正确的。
应该强调计划，如此它不被错误首先订定。
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编号： 毕业设计(论文)外文翻译 （原文）
院 （系）：桂林电子科技大学 专 业： 电子信息工程 学生姓名： xx 学 号： xxxxxxxxxxxxx 指导教师单位：桂林电子科技大学 姓 名： xxxx 职 称： xx
2014年x月xx日 桂林电子科技大学毕业设计（论文）报告用纸 第 1 页 共 9 页 Timing on and off power supply uses The switching power supply products are widely used in industrial automation and control, military equipment, scientific equipment, LED lighting, industrial equipment,communications equipment,electrical equipment,instrumentation, medical equipment, semiconductor cooling and heating, air purifiers, electronic refrigerator, LCD monitor, LED lighting, communications equipment, audio-visual products, security, computer chassis, digital products and equipment and other fields. Introduction With the rapid development of power electronics technology, power electronics equipment and people's work, the relationship of life become increasingly close, and electronic equipment without reliable power, into the 1980s, computer power and the full realization of the switching power supply, the first to complete the computer Power new generation to enter the switching power supply in the 1990s have entered into a variety of electronic, electrical devices, program-controlled switchboards, communications, electronic testing equipment power control equipment, power supply, etc. have been widely used in switching power supply, but also to promote the rapid development of the switching power supply technology . Switching power supply is the use of modern power electronics technology to control the ratio of the switching transistor to turn on and off to maintain a stable output voltage power supply, switching power supply is generally controlled by pulse width modulation (PWM) ICs and switching devices (MOSFET, BJT) composition. Switching power supply and linear power compared to both the cost and growth with the increase of output power, but the two different growth rates. A power point, linear power supply costs, but higher than the switching power supply. With the development of power electronics technology and innovation, making the switching power supply technology to continue to innovate, the turning points of this cost is increasingly move to the low output power side, the switching power supply provides a broad space for development. The direction of its development is the high-frequency switching power supply, high frequency switching power supply miniaturization, and switching power supply into a wider range of application areas, especially in high-tech fields, and promote the miniaturization of high-tech products, light of. In addition, the development and application of the switching power supply in terms of energy conservation, resource conservation and environmental protection are of great significance. 桂林电子科技大学毕业设计（论文）报告用纸 第 2 页 共 9 页 classification Modern switching power supply, there are two: one is the DC switching power supply; the other is the AC switching power supply. Introduces only DC switching power supply and its function is poor power quality of the original eco-power (coarse) - such as mains power or battery power, converted to meet the equipment requirements of high-quality DC voltage (Varitronix) . The core of the DC switching power supply DC / DC converter. DC switching power supply classification is dependent on the classification of DC / DC converter. In other words, the classification of the classification of the DC switching power supply and DC/DC converter is the classification of essentially the same, the DC / DC converter is basically a classification of the DC switching power supply. DC /DC converter between the input and output electrical isolation can be divided into two categories: one is isolated called isolated DC/DC converter; the other is not isolated as non-isolated DC / DC converter. Isolated DC / DC converter can also be classified by the number of active power devices. The single tube of DC / DC converter Forward (Forward), Feedback (Feedback) two. The double-barreled double-barreled DC/ DC converter Forward (Double Transistor Forward Converter), twin-tube feedback (Double Transistor Feedback Converter), Push-Pull (Push the Pull Converter) and half-bridge (Half-Bridge Converter) four. Four DC / DC converter is the full-bridge DC / DC converter (Full-Bridge Converter). Non-isolated DC / DC converter, according to the number of active power devices can be divided into single-tube, double pipe, and four three categories. Single tube to a total of six of the DC / DC converter, step-down (Buck) DC / DC converter, step-up (Boost) DC / DC converters, DC / DC converter, boost buck (Buck Boost) device of Cuk the DC / DC converter, the Zeta DC / DC converter and SEPIC, the DC / DC converter. DC / DC converters, the Buck and Boost type DC / DC converter is the basic buck-boost of Cuk, Zeta, SEPIC, type DC / DC converter is derived from a single tube in this six. The twin-tube cascaded double-barreled boost (buck-boost) DC / DC converter DC / DC converter. Four DC / DC converter is used, the full-bridge DC / DC converter (Full-Bridge Converter). Isolated DC / DC converter input and output electrical isolation is usually transformer to achieve the function of the transformer has a transformer, so conducive to the expansion of the converter output range of applications, but also easy to achieve different voltage output , or a variety of the same voltage output. Power switch voltage and current rating, the converter's output power is usually proportional to the number of switch. The more the number of switch, the greater the output power of the DC / DC converter, four type than the two output power is twice as large,