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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.。
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Worlds Collide:
Exploring the Use of Social Media Technologies for
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世界的碰撞：
探索社交媒体技术在在线学习的应用
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毕业设计论文外文文献翻译
毕业设计(论文）外文文献翻译院系：财务与会计学院年级专业：201＊级财务管理姓名:学号：132148*＊*附件: 财务风险管理【Abstract】Although financial risk has increased significantly in recent years risk and risk management are not contemporary issues。
The result of increasingly global markets is that risk may originate with events thousands of miles away that have nothing to do with the domestic market。
Information is available instantaneously which means that change and subsequent market reactions occur very quickly。
The economic climate and markets can be affected very quickly by changes in exchange rates interest rates and commodity prices。
Counterparties can rapidly become problematic。
As a result it is important to ensure financial risks are identified and managed appropriately. Preparation is a key component of risk management。
【Key Words】Financial risk，Risk management，YieldsI. Financial risks arising1.1What Is Risk1.1.1The concept of riskRisk provides the basis for opportunity. The terms risk and exposure have subtle differences in their meaning. Risk refers to the probability of loss while exposure is the possibility of loss although they are often used interchangeably。
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毕设外文文献+翻译1外文翻译外文原文CHANGING ROLES OF THE CLIENTS、ARCHITECTSAND CONTRACTORS THROUGH BIMAbstract:Purpose –This paper aims to present a general review of the practical implications of building information modelling (BIM) based on literature and case studies. It seeks to address the necessity for applying BIM and re-organising the processes and roles in hospital building projects. This type of project is complex due to complicated functional and technical requirements, decision making involving a large number of stakeholders, and long-term development processes.Design/methodology/approach–Through desk research and referring to the ongoing European research project InPro, the framework for integrated collaboration and the use of BIM are analysed.Findings –One of the main findings is the identification of the main factors for a successful collaboration using BIM, which can be recognised as “POWER”: product information sharing (P),organisational roles synergy (O), work processes coordination (W), environment for teamwork (E), and reference data consolidation (R).Originality/value –This paper contributes to the actual discussion in science and practice on the changing roles and processes that are required to develop and operate sustainable buildings with the support of integrated ICT frameworks and tools. It presents the state-of-the-art of European research projects and some of the first real cases of BIM application inhospital building projects.Keywords:Europe, Hospitals, The Netherlands, Construction works, Response flexibility, Project planningPaper type :General review1. IntroductionHospital building projects, are of key importance, and involve significant investment, and usually take a long-term development period. Hospital building projects are also very complex due to the complicated requirements regarding hygiene, safety, special equipments, and handling of a large amount of data. The building process is very dynamic and comprises iterative phases and intermediate changes. Many actors with shifting agendas, roles and responsibilities are actively involved, such as: the healthcare institutions, national and local governments, project developers, financial institutions, architects, contractors, advisors, facility managers, and equipment manufacturers and suppliers. Such building projects are very much influenced, by the healthcare policy, which changes rapidly in response to the medical, societal and technological developments, and varies greatly between countries (World Health Organization, 2000). In The Netherlands, for example, the way a building project in the healthcare sector is organised is undergoing a major reform due to a fundamental change in the Dutch health policy that was introduced in 2008.The rapidly changing context posts a need for a building with flexibility over its lifecycle. In order to incorporate life-cycle considerations in the building design, construction technique, and facility management strategy, a multidisciplinary collaboration is required. Despite the attempt for establishing integrated collaboration, healthcare building projects still facesserious problems in practice, such as: budget overrun, delay, and sub-optimal quality in terms of flexibility, end-user?s dissatisfaction, and energy inefficiency. It is evident that the lack of communication and coordination between the actors involved in the different phases of a building project is among the most important reasons behind these problems. The communication between different stakeholders becomes critical, as each stakeholder possesses different setof skills. As a result, the processes for extraction, interpretation, and communication of complex design information from drawings and documents are often time-consuming and difficult. Advanced visualisation technologies, like 4D planning have tremendous potential to increase the communication efficiency and interpretation ability of the project team members. However, their use as an effective communication tool is still limited and not fully explored. There are also other barriers in the information transfer and integration, for instance: many existing ICT systems do not support the openness of the data and structure that is prerequisite for an effective collaboration between different building actors or disciplines.Building information modelling (BIM) offers an integrated solution to the previously mentioned problems. Therefore, BIM is increasingly used as an ICT support in complex building projects. An effective multidisciplinary collaboration supported by an optimal use of BIM require changing roles of the clients, architects, and contractors; new contractual relationships; and re-organised collaborative processes. Unfortunately, there are still gaps in the practical knowledge on how to manage the building actors to collaborate effectively in their changing roles, and todevelop and utilise BIM as an optimal ICT support of the collaboration.This paper presents a general review of the practical implications of building information modelling (BIM) based on literature review and case studies. In the next sections, based on literature and recent findings from European research project InPro, the framework for integrated collaboration and the use of BIM are analysed. Subsequently, through the observation of two ongoing pilot projects in The Netherlands, the changing roles of clients, architects, and contractors through BIM application are investigated. In conclusion, the critical success factors as well as the main barriers of a successful integrated collaboration using BIM are identified.2. Changing roles through integrated collaboration and life-cycle design approachesA hospital building project involves various actors, roles, and knowledge domains. In The Netherlands, the changing roles of clients, architects, and contractors in hospital building projects are inevitable due the new healthcare policy. Previously under the Healthcare Institutions Act (WTZi), healthcare institutions were required to obtain both a license and a building permit for new construction projects and major renovations. The permit was issued by the Dutch Ministry of Health. The healthcare institutions were then eligible to receive financial support from the government. Since 2008, new legislation on the management of hospital building projects and real estate has come into force. In this new legislation, a permit for hospital building project under the WTZi is no longer obligatory, nor obtainable (Dutch Ministry of Health, Welfare and Sport, 2008). This change allows more freedom from the state-directed policy, and respectively,allocates more responsibilities to the healthcare organisations to deal with the financing and management of their real estate. The new policy implies that the healthcare institutions are fully responsible to man age and finance their building projects and real estate. The government?s support for the costs of healthcare facilities will no longer be given separately, but will be included in the fee for healthcare services. This means that healthcare institutions must earn back their investment on real estate through their services. This new policy intends to stimulate sustainable innovations in the design, procurement and management of healthcare buildings, which will contribute to effective and efficient primary healthcare services.The new strategy for building projects and real estate management endorses an integrated collaboration approach. In order to assure the sustainability during construction, use, and maintenance, the end-users, facility managers, contractors and specialist contractors need to be involved in the planning and design processes. The implications of the new strategy are reflected in the changing roles of the building actors and in the new procurement method.In the traditional procurement method, the design, and its details, are developed by the architect, and design engineers. Then, the client (the healthcare institution) sends an application to the Ministry of Healthto obtain an approval on the building permit and the financial support from the government. Following this, a contractor is selected through a tender process that emphasises the search for the lowest-price bidder. During the construction period, changes often take place due to constructability problems of the design and new requirements from the client.Because of the high level of technical complexity, and moreover, decision-making complexities, the whole process from initiation until delivery of a hospital building project can take up to ten years time. After the delivery, the healthcare institution is fully in charge of the operation of the facilities. Redesigns and changes also take place in the use phase to cope with new functions and developments in the medical world.The integrated procurement pictures a new contractual relationship between the parties involved in a building project. Instead of a relationship between the client and architect for design, and the client and contractor for construction, in an integrated procurement the client only holds a contractual relationship with the main party that is responsible for both design and construction. The traditional borders between tasks and occupational groups become blurred since architects, consulting firms, contractors, subcontractors, and suppliers all stand on the supply side in the building process while the client on the demand side. Such configuration puts the architect, engineer and contractor in a very different position that influences not only their roles, but also their responsibilities, tasks and communication with the client, the users, the team and other stakeholders.The transition from traditional to integrated procurement method requires a shift of mindset of the parties on both the demand and supply sides. It is essential for the client and contractor to have a fair and open collaboration in which both can optimally use their competencies. The effectiveness of integrated collaboration is also determined by the client?s capacity and strategy to organize innovative tendering procedures.A new challenge emerges in case of positioning an architect in a partnership with the contractor instead of with the client. In case of the architect enters a partnership with the contractor, an important issues is how to ensure the realisation of the architectural values as well as innovative engineering through an efficient construction process. In another case, the architect can stand at the client?s side in a strategic advisory role instead of being the designer. In this case, the architect?s responsibility is translating client?s requirements and wishes into the architectural values to be included in the design specification, and evaluating the contractor?s proposal against this. In any of this new role, the architect holds the responsibilities as stakeholder interest facilitator, custodian of customer value and custodian of design models.The transition from traditional to integrated procurement method also brings consequences in the payment schemes. In the traditional building process, the honorarium for the architect is usually based on a percentage of the project costs; this may simply mean that the more expensive the building is, the higher the honorarium will be. The engineer receives the honorarium based on the complexity of the design and the intensity of the assignment. A highly complex building, which takes a number of redesigns, is usually favourable for the engineers in terms of honorarium. A traditional contractor usually receives the commission based on the tender to construct the building at the lowest price by meeting the minimum specifications given by the client. Extra work due to modifications is charged separately to the client. After the delivery, the contractor is no longer responsible for the long-term use of the building. In the traditional procurement method, all risks are placed with theclient.In integrated procurement method, the payment is based on the achieved building performance; thus, the payment is non-adversarial. Since the architect, engineer and contractor have a wider responsibility on the quality of the design and the building, the payment is linked to a measurement system of the functional and technical performance of the building over a certain period of time. The honorarium becomes an incentive to achieve the optimal quality. If the building actors succeed to deliver a higher added-value thatexceed the minimum client?s requirements, they will receive a bonus in accordance to the client?s extra gain. The level of transparency is also improved. Open book accounting is an excellent instrument provided that the stakeholders agree on the information to be shared and to its level of detail (InPro, 2009).Next to the adoption of integrated procurement method, the new real estate strategy for hospital building projects addresses an innovative product development and life-cycle design approaches. A sustainable business case for the investment and exploitation of hospital buildings relies on dynamic life-cycle management that includes considerations and analysis of the market development over time next to the building life-cycle costs (investment/initial cost, operational cost, and logistic cost). Compared to the conventional life-cycle costing method, the dynamic life-cycle management encompasses a shift from focusing only on minimizing the costs to focusing on maximizing the total benefit that can be gained. One of the determining factors for a successful implementation of dynamic life-cycle management is the sustainable design of the building and building components, which means that the design carriessufficient flexibility to accommodate possible changes in the long term (Prins, 1992).Designing based on the principles of life-cycle management affects the role of the architect, as he needs to be well informed about the usage scenarios and related financial arrangements, the changing social and physical environments, and new technologies. Design needs to integrate people activities and business strategies over time. In this context, the architect is required to align the design strategies with the organisational, local and global policies on finance, business operations, health and safety, environment, etc.The combination of process and product innovation, and the changing roles of the building actors can be accommodated by integrated project delivery or IPD (AIA California Council, 2007). IPD is an approach that integrates people, systems, business structures and practices into a process that collaboratively harnesses the talents and insights of all participants to reduce waste and optimize efficiency through all phases of design, fabrication and construction. IPD principles can be applied to a variety of contractual arrangements. IPD teams will usually include members well beyond the basic triad of client, architect, and contractor. At a minimum, though, an Integrated Project should include a tight collaboration between the client, the architect, and the main contractor ultimately responsible for construction of the project, from the early design until the project handover. The key to a successful IPD is assembling a team that is committed to collaborative processes and is capable of working together effectively. IPD is built on collaboration. As a result, it can only be successful if the participants share and apply common values and goals.3. Changing roles through BIM applicationBuilding information model (BIM) comprises ICT frameworks and tools that can support the integrated collaboration based on life-cycle design approach. BIM is a digital representation of physical and functional characteristics of a facility. As such it serves as a shared knowledge resource for information about a facility forming a reliable basis for decisions during its lifecycle from inception onward (National Institute of Building Sciences NIBS, 2007). BIM facilitates time and place independent collaborative working. A basic premise of BIM is collaboration by different stakeholders at different phases of the life cycle of a facility to insert, extract, update or modify information in the BIM to support and reflect the roles of that stakeholder. BIM in its ultimate form, as a shared digital representation founded on open standards for interoperability, can become a virtual information model to be handed from the design team to the contractor and subcontractors and then to the client.BIM is not the same as the earlier known computer aided design (CAD). BIM goes further than an application to generate digital (2D or 3D) drawings. BIM is an integrated model in which all process and product information is combined, stored, elaborated, and interactively distributed to all relevant building actors. As a central model for all involved actors throughout the project lifecycle, BIM develops andevolves as the project progresses. Using BIM, the proposed design and engineering solutions can be measured against the client?s requirements and expected building performance. The functionalities of BIM to support the design process extend to multidimensional (nD), including: three-dimensional visualisation and detailing, clash detection, material schedule, planning, costestimate, production and logistic information, and as-built documents. During the construction process, BIM can support the communication between the building site, the factory and the design office– which is crucial for an effective and efficient prefabrication and assembly processes as well as to prevent or solve problems related to unforeseen errors or modifications. When the building is in use, BIM can be used in combination with the intelligent building systems to provide and maintain up-to-date information of the building performance, including the life-cycle cost.To unleash the full potential of more efficient information exchange in the AEC/FM industry in collaborative working using BIM, both high quality open international standards and high quality implementations of these standards must be in place. The IFC open standard is generally agreed to be of high quality and is widely implemented in software. Unfortunately, the certification process allows poor quality implementations to be certified and essentially renders the certified software useless for any practical usage with IFC. IFC compliant BIM is actually used less than manual drafting for architects and contractors, and show about the same usage for engineers. A recent survey shows that CAD (as a closed-system) is still the major form of technique used in design work (over 60 per cent) while BIM is used in around 20 percent of projects for architects and in around 10 per cent of projects for engineers and contractors.The application of BIM to support an optimal cross-disciplinary and cross-phase collaboration opens a new dimension in the roles and relationships between the building actors. Several most relevant issues are: the new role of a model manager; the agreement on the access right and IntellectualProperty Right (IPR); the liability and payment arrangement according to the type of contract and in relation to the integrated procurement; and the use of open international standards.Collaborative working using BIM demands a new expert role of a model manager who possesses ICT as well as construction process know-how (InPro, 2009). The model manager deals with the system as well as with the actors. He provides and maintains technological solutions required for BIM functionalities, manages the information flow, and improves the ICT skills of the stakeholders. The model manager does not take decisions on design and engineering solutions, nor the organisational processes, but his roles in the chain of decision making are focused on:the development of BIM, the definition of the structure and detail level of the model, and the deployment of relevant BIM tools, such as for models checking, merging, and clash detections;the contribution to collaboration methods, especially decision making and communication protocols, task planning, and risk management;and the management of information, in terms of data flow and storage, identification of communication errors, and decision or process (re-)tracking.Regarding the legal and organisational issues, one of the actual questions is: “In what way does the intellectual property right (IPR) in collaborative working using BIM differ from the IPR in a traditional teamwork?”. In terms of combine d work, the IPR of each element is at tached to its creator. Although it seems to be a fully integrated design, BIM actually resulted from a combination of works/elements; for instance: the outline of the building design, is created by the architect, the design for theelectrical system, is created by the electrical contractor, etc. Thus, in case of BIM as a combined work, the IPR is similar to traditional teamwork. Working with BIM with authorship registration functionalities may actually make it easier to keep track of the IPR.How does collaborative working, using BIM, effect the contractual relationship? On the one hand,collaborative working using BIM does not necessarily change the liability position in the contract nor does it obligate an alliance contract. The General Principles of BIM A ddendum confirms: …This does not effectuate or require a restructuring of contractual relationships or shifting of risks between or among the Project Participants other than as specifically required per the Protocol Addendum and its Attachments? (ConsensusDOCS, 2008). On the other hand, changes in terms of payment schemes can be anticipated. Collaborative processes using BIM will lead to the shifting of activities from to the early design phase. Much, if not all, activities in the detailed engineering and specification phase will be done in the earlier phases. It means that significant payment for the engineering phase, which may count up to 40 per cent of the design cost, can no longer be expected. As engineering work is done concurrently with the design, a new proportion of the payment in the early design phase is necessary.4. Review of ongoing hospital building projects using BIMIn The Netherlands, the changing roles in hospital building projects are part of the strategy, which aims at achieving a sustainable real estate in response to the changing healthcare policy. Referring to literature and previous research, the main factors that influence the success of the changing roles can be concluded as: the implementation of an integrated procurementmethod and a life-cycle design approach for a sustainable collaborative process; the agreement on the BIM structure and the intellectual rights; and the integration of the role of a model manager. The preceding sections have discussed the conceptual thinking on how to deal with these factors effectively. This current section observes two actual projects and compares the actual practice with the conceptual view respectively.The main issues, which are observed in the case studies, are: the selected procurement method and the roles of the involved parties within this method;the implementation of the life-cycle design approach;the type, structure, and functionalities of BIM used in the project;the openness in data sharing and transfer of the model, and the intended use of BIM in the future; and the roles and tasks of the model manager.The pilot experience of hospital building projects using BIM in the Netherlands can be observed at University Medical Centre St Radboud (further referred as UMC) and Maxima Medical Centre (further referred as MMC). At UMC, the new building project for the Faculty of Dentistry in the city of Nijmegen has been dedicated as a BIM pilot project. At MMC, BIM is used in designing new buildings for Medical Simulation and Mother-and-Child Centre in the city of Veldhoven.The first case is a project at the University Medical Centre (UMC) St Radboud. UMC is more than just a hospital. UMC combines medical services, education and research. More than 8500 staff and 3000 students work at UMC. As a part of the innovative real estate strategy, UMC has considered to use BIM for its building projects. The new development of the Faculty ofDentistry and the surrounding buildings on the Kapittelweg in Nijmegen has been chosen as a pilot project to gather practical knowledge and experience on collaborative processes with BIM support.The main ambition to be achieved through the use of BIM in the building projects at UMC can be summarised as follows: using 3D visualisation to enhance the coordination and communication among the building actors, and the user participation in design;integrating the architectural design with structural analysis, energy analysis, cost estimation, and planning;interactively evaluating the design solutions against the programme of requirements and specifications;reducing redesign/remake costs through clash detection during the design process; andoptimising the management of the facility through the registration of medical installations andequipments, fixed and flexible furniture, product and output specifications, and operational data.The second case is a project at the Maxima Medical Centre (MMC). MMC is a large hospital resulted from a merger between the Diaconessenhuis in Eindhoven and St Joseph Hospital in Veldhoven. Annually the 3,400 staff of MMC provides medical services to more than 450,000 visitors and patients. A large-scaled extension project of the hospital in Veldhoven is a part of its real estate strategy. A medical simulation centre and a women-and-children medical centre are among the most important new facilities within this extension project. The design has been developed using 3D modelling with several functionalities of BIM.The findings from both cases and the analysis are as follows.Both UMC and MMC opted for a traditional procurement method in which the client directly contracted an architect, a structural engineer, and a mechanical, electrical and plumbing (MEP) consultant in the design team. Once the design and detailed specifications are finished, a tender procedure will follow to select a contractor. Despite the choice for this traditional method, many attempts have been made for a closer and more effective multidisciplinary collaboration. UMC dedicated a relatively long preparation phase with the architect, structural engineer and MEP consultant before the design commenced. This preparation phase was aimed at creating a common vision on the optimal way for collaboration using BIM as an ICT support. Some results of this preparation phase are: a document that defines the common ambition for the project and the collaborative working process and a semi-formal agreement that states the commitment of the building actors for collaboration. Other than UMC, MMC selected an architecture firm with an in-house engineering department. Thus, the collaboration between the architect and structural engineer can take place within the same firm using the same software application.Regarding the life-cycle design approach, the main attention is given on life-cycle costs, maintenance needs, and facility management. Using BIM, both hospitals intend to get a much better insight in these aspects over the life-cycle period. The life-cycle sustainability criteria are included in the assignments for the design teams. Multidisciplinary designers and engineers are asked to collaborate more closely and to interact with the end-users to address life-cycle requirements. However, ensuring the building actors to engage in an integrated collaboration to generate sustainable design solutions that meet the life-cycle。
毕业设计外文文献翻译(原文+译文)
Environmental problems caused by Istanbul subway excavation and suggestionsfor remediation伊斯坦布尔地铁开挖引起的环境问题及补救建议Ibrahim Ocak Abstract：Many environmental problems caused by subway excavations have inevitably become an important point in city life. These problems can be categorized as transporting and stocking of excavated material, traffic jams, noise, vibrations, piles of dust mud and lack of supplies. Although these problems cause many difficulties,the most pressing for a big city like Istanbul is excava tion,since other listed difficulties result from it. Moreover, these problems are environmentally and regionally restricted to the period over which construction projects are underway and disappear when construction is finished. Currently, in Istanbul, there are nine subway construction projects in operation, covering approximately 73 km in length; over 200 km to be constructed in the near future. The amount of material excavated from ongoing construction projects covers approximately 12 million m3. In this study, problems—primarily, the problem with excavation waste(EW)—caused by subway excavation are analyzed and suggestions for remediation are offered.摘要：许多地铁开挖引起的环境问题不可避免地成为城市生活的重要部分。
毕业设计外文文献翻译范文
毕业设计外文文献翻译专业学生姓名班级学号指导教师优集学院外文资料名称：Knowledge-Based Engineeri--ng Design Methodology外文资料出处：Int.J.Engng Ed.Vol.16.No.1附件： 1.外文资料翻译译文2.外文原文基于知识工程(KBE)设计方法D. E. CALKINS1.背景复杂系统的发展需要很多工程和管理方面的知识、决策，它要满足很多竞争性的要求。
设计被认为是决定产品最终形态、成本、可靠性、市场接受程度的首要因素。
高级别的工程设计和分析过程(概念设计阶段)特别重要，因为大多数的生命周期成本和整体系统的质量都在这个阶段。
产品成本的压缩最可能发生在产品设计的最初阶段。
整个生命周期阶段大约百分之七十的成本花费在概念设计阶段结束时，缩短设计周期的关键是缩短概念设计阶段，这样同时也减少了工程的重新设计工作量。
工程权衡过程中采用良好的估计和非正式的启发进行概念设计。
传统CAD工具对概念设计阶段的支持非常有限。
有必要，进行涉及多个学科的交流合作来快速进行设计分析(包括性能，成本，可靠性等)。
最后，必须能够管理大量的特定领域的知识。
解决方案是在概念设计阶段包含进更过资源，通过消除重新设计来缩短整个产品的时间。
所有这些因素都主张采取综合设计工具和环境，以在早期的综合设计阶段提供帮助。
这种集成设计工具能够使由不同学科的工程师、设计者在面对复杂的需求和约束时能够对设计意图达成共识。
那个设计工具可以让设计团队研究在更高级别上的更多配置细节。
问题就是架构一个设计工具，以满足所有这些要求。
2.虚拟(数字)原型模型现在需要是一种代表产品设计为得到一将允许一产品的早发展和评价的真实事实上原型的过程的方式。
虚拟样机将取代传统的物理样机，并允许设计工程师，研究“假设”的情况，同时反复更新他们的设计。
真正的虚拟原型，不仅代表形状和形式，即几何形状，它也代表如重量，材料，性能和制造工艺的非几何属性。
毕业设计(论文)外文翻译【范本模板】
华南理工大学广州学院本科生毕业设计(论文）翻译英文原文名Review of Vibration Analysis Methods for Gearbox Diagnostics and Prognostics中文译名对变速箱振动分析的诊断和预测方法综述学院汽车工程学院专业班级车辆工程七班学生姓名刘嘉先学生学号201130085184指导教师李利平填写日期2015年3月15日英文原文版出处：Proceedings of the 54th Meeting of the Society for Machinery Failure Prevention Technology, Virginia Beach，V A, May 1-4，2000，p. 623-634译文成绩：指导教师(导师组长）签名：译文：简介特征提取技术在文献中有描述;然而，大多数人似乎掩盖所需的特定的预处理功能。
一些文件没有提供足够的细节重现他们的结果，并没有一个全面的比较传统的功能过渡齿轮箱数据。
常用术语,如“残差信号”,是指在不同的文件不同的技术.试图定义了状态维修社区中的常用术语和建立所需的特定的预处理加工特性。
本文的重点是对所使用的齿轮故障检测功能。
功能分为五个不同的组基于预处理的需要。
论文的第一部分将提供预处理流程的概述和其中每个特性计算的处理方案。
在下一节中，为特征提取技术描述，将更详细地讨论每一个功能。
最后一节将简要概述的宾夕法尼亚州立大学陆军研究实验室的CBM工具箱用于齿轮故障诊断。
特征提取概述许多类型的缺陷或损伤会增加机械振动水平。
这些振动水平，然后由加速度转换为电信号进行数据测量。
原则上,关于受监视的计算机的健康的信息被包含在这个振动签名。
因此，新的或当前振动签名可以与以前的签名进行比较,以确定该元件是否正常行为或显示故障的迹象。
在实践中，这种比较是不能奏效的。
由于大的变型中,签名的直接比较是困难的。
相反,一个涉及从所述振动署名数据特征提取更多有用的技术也可以使用。
毕业设计外文翻译样本
Influence of underground water seepage flow on surrounding rockdeformation of multi-arch tunnelAbstract: Based on a typical multi-arch tunnel in a freeway, the fast Lagrangian analysis of continua in3 dimensions(FLAC ) was used to calculate the surrounding rock deformation of the tunnel under which the effect of underground water seepage flow was taken into account or not. The distribution of displacement field around the multi-arch tunnel, which is influenced by the seepage field, was gained. The result indicates that the settlement values of the vault derived from coupling analysis are bigger when considering the seepage flow effect than that not considering. Through the contrast of arch subsidence quantities calculated by two kinds of computation situations, and the comparison between the calculated and measured value of tunnel vault settlement, it is found that the calculated value(5.7−6.0 mm) derived from considering the seepage effect is more close to the measured value(5.8−6.8 mm). Therefore, it is quite necessary to consider the seepage flow effect of the underground water in aquiferous stratum for multi-arch tunnel design. key words: multi-arch tunnel; underground water seepage flow; coupling flow and stress; surrounding rock deformation; vault settlement1 IntroductionWith high speed development of our national economy, the highway is constructed on large-scale all around the country. Along the freeway from Changsha to Chongqing(one section of which is from Changde to Jishou), many tunnels have to be constructed. As these tunnels’s topography and geomorphic conditions are very complex and the rain is very rich, the invasion of underground water and surface water is a difficult problem in the tunnel construction and its future function. In the past railway and highway tunnel construction, some effective waterproof construction technologies were proposed . But the researches on the mechanism of coupling function of fluid and stress and its influence on tunnels are not enough. For example, LIU and CHENcalculated and analyzed the double-arch tunnel structure in water-eroded groove but did not consider the underground water seepage force. YANG et al studied the earthquake response of large span and double-arch shallow tunnel, combining with dynamic stress but without underground water seepage stress. In fact, tunnel excavation forms two secondary stresses fields that can change the distribution of initial rock stress field and theunderground water seepage field. And the seepage flow of underground water also has importantinfluence on the stability of tunnel.Generally speaking, when the surface water seeps in underground, it will constitute the initial seepage flow field together with the underground water. But after tunnel excavation the initial seepage flow field will be destructed. In order to achieve a newbalance, it can produce a new seepage flow field around the tunnel with the underground water flowing into the tunnel. The pore-water pressure can change the stress field of adjacent rock mass. This problem is the coupling flow and stress question on which some scholars study now . LI et al analyzed the subsea tunnel withcoupling process and LEE and NAM discussed the seepage flow force around the tunnel with coupling analysis. In order to know the effect of underground water seepage flow on the surrounding rock deformation of tunnel, a multi-arch tunnel(named Bi-Ma-Xi tunnel) engineering was analyzed with FLAC in this work.2 Engineering and geology conditions2.1 TopographyThe tunnel locates at a hill on long-term weathering and denudation action. In the tunnel area, there are some gullies that primarily s trike towards north and some strike from east to north. Tunnel axis direction and topographic contour line are intersected with orthogonal or a great angle at section K218+087−K218+380 and with a small angle or even parallel at section K218+380− K218+565. The topography is rather steep and forms a “V” type gully. The general hill strike is about 340˚, which is close from north to south. The topography slope is about 15˚−35˚. The green vegetation is mainly the small bamboo and herbaceous plants. The rock bed is visible in some places.2.2 Lithologyccording to engineering geology survey and drilling exposure data, the stratum of3D [1−3] 4][5]surveying area from young to old is as follows.The Quaternary Holocene(Qh): the soil-like loam layer, snuff color, plastic-stiffly,0−4.60 m thick. This layer is ignored in numerical model.The Upper Cretaceous (K2j): Sandstone layer, red brown or palm fibre or dust colour,fine-grained structure. The calcareous cemented rock layer is mixed with mud cemented rock layer and the former is the main part and it is thin and medium thickness structural layer. The horizontal bedding layer develops and the dip angle is small. According to weathered degree the stratum can be divided into three layers from the top down: intensely, weakly and tinily weathered layer. The sketch map of geology section is shown in Fig.1.Fig.1 Sketch of geological profile for tunnel2.3 Geology constitutionIn tunnel area there is no large fracture structure and nor any new tectogenesis. The geology constitution is a monoclinal structure. The rock dip direction of general occurrence is 95˚−115˚. The dip angle distribution ranges from 8˚ to15˚. Three sets of joint crack develop: 1) dip direction 148˚, dip angle 89˚;2) dip direction 350˚, dip angle 56˚; 3) dip direction 225˚, dip angle 77˚. The joint cracks mostly twist with pressure and crack faces are almost close. Minorities of the crack faces are patulous and the distance between two cracks often varies from 5 to 20 cm. The connectivity is fairly good.3 Construction of 3D numerical model3.1 model of numerical calculationThis tunnel is a freeway multi-arch tunnel, of which the left one and right one are general parallel. The two tunnels are about symmetrical by the middle arch wall. The average thickness of middle wall is 2.1 m. The key dimensions of tunnel section are shown in Fig.2.Fig.2 Sketch of multi-tunnel cross section (unit: cm)When modeling the tunnel, the direction along the tunnel is y-axis and in horizontal plane the perpendicularity of tunnel direction is x-axis and plumb upward is z-axis. The influence of tunnel excavation is considered. The radius of influence range is above 3 times of one tunnel span. So in width direction, 50 m extends respectively outside the left and right tunnel, plus the span itself, width direction calculation range is 125 m. Downwards from the original point is 3 times of the height of the tunnel, which equals 45 m and upward is till the earth’s surface (does not consider the clay layer, calculating depth range includes intensely, weakly, tinily weathered red sandstone from above to below respectively). The buried depth of the tunnel is about 25 m. Plus the 10 m of its height, in z-axis the depth is 80 m. Along the tunnel direction an unit length is considered because tunnel excavation can be considered asa plane-strain problem. The size of the 3D numerical model is 125 m×80 m×1 m. The 3D numerical model and its coordinate axis location are shown in Fig.3.Fig.3 3D numerical model of tunnel in FLACThe displacement boundary conditions are adopted in numerical model. Bottom border is constrained with vertical displacement and upper border is free border. Both left and right border are restrained with horizontal displacement. The same boundary conditions are applied in both the front and back borders in y-axis.3.2 Calculation parametersThe mechanics parameters in numerical analysis are provided by geotechnical engineering investigation data and combined with the national criterion need and parameters discount request in numerical simulation. The mechanics parameters of the surrounding rock and the C25 concrete middle arch wall are listed in Table 1. The surrounding rock and the concrete intensity criteria adopted is the elastic-plastic criterion of Mohr-Coulomb. Table 2 shows the surrounding rock relevant seepage flow parameters when coupling problem is considered in numerical simulation. Table 3 lists the parameters of shot concrete(primary lining) and anchor support structure of the multi-arch tunnel. In this calculation process, the parameters of Grade IV surrounding rock supporting system are adopted. And only the affection of the anchor and shotconcrete is considered. The effect of secondary lining is not considered in numerical simulation.4 Discussion on calculation results4.1 Surrounding rock deformation characteristics without underground water seepage flowBased on the established numerical model, the process in which the underground water seepage flow function was not considered was carried on by FLAC . Fig.4 shows the vertical displacement contour-line map in this instance after multi-arch tunnel excavation. From Fig.4 it can be obviously seen that nearby the tunnel excavation region the rock deformation is relatively serious. The vault rock displacement is negative, indicating that the displacement direction is vertical downwards and subsidence occurs. But around the tunnel bottom the surrounding rock displacement is positive, indicating that the direction is vertical upwards and bulging phenomenon occurs.In the process of numerical calculation, the left and right tunnels were simulated simultaneously, namely they were excavated in the identical section plane simultaneously, that is to say, the influence of the construction order is not considered. In the computation process ofFLAC , some interesting grid points were selected to monitor their vertical displacement. The monitored grid points’ number and corresponding coordinate position are listed in Table 4.Fig.5 shows the time process curves of z-displacement (absolute value) of the monitored grid points around left tunnel vault. From Fig.5 it can be seen that the vertical displacement value(or called settlement value) of tunnel vault surrounding rock has relationship with its own position. The clos er the grid point’s position away from the tunnel excavation region, the larger the settlement value. For example, on the middle upper grid point (41 ) of left tunnel, its final calculation settlement value is 3.7 mm, and another grid poi nts’ values are getting smaller with the distance becoming longer.Fig.5 Time process curves of z-displacement of monitored grid points around le ft tunnel vault4.2 Surrounding rock deformation characteristics with underground water seepage flowThe influencing factors of surrounding rock deformation after tunnel excavation in Refs.[10−13], mainly concentrating on the grade of surrounding rock, excavating and supporting method, the neighbor construction load and the construction working procedure. Generally it almost does not consider the influence of underground water seepage flow. But in fact, the underground water existence has important influence on the surrounding rock deformation. For instance, in the excavation and tunnel engineering, the underground water seepage flow can cause quite big displacement of the soil or rock mass and even threaten the safety of engineering . In this study, some quantitative researches on the influence of surrounding rock deformation were carried out by underground water seepage flow.The stratum is fully saturated with water before tunnel is excavated. The seepage flow boundary condition includes that thepore-water pressure of the top surface is limited to zero and the two sides as well as the base boundary are water-proof boundaries . Before tunnel excavation the pore pressure of the stratum is hydro-static pressure. After tunnel excavation, around the tunnel excavation boundary is simulated by a free water seepage flow boundary where the adjacent underground water infiltrates into the excavated area. And the seepage flow field of surrounding rock has been changed with the excavation being carried on. Then the coupling analysis was executed by FLAC .Fig.6 shows the vertical displacement contour-line map after multi-arch tunnel excavation when considering the underground water seepage flow function. Obviously it can be seen that in coupling analysis the arch subsidence quantity is larger than that of not considering seepage function andthe affected region is also wider than that of the former as shown in Fig.4.Fig.6 z-displacement contour-line map of surrounding rock when considering underground water seepage flow function (unit: mm)coupling analysis, as the change of pore pressure in surrounding rock, the effective stress will be changed and it will cause the rock porosity ratio to reduce, leading to a larger arch subsidence quantity compared with that of not considering the seepage flow effect. But the vertical displacements at the bottom of the tunnel are not changed a lot. Fig.7 shows the calculated vertical displacement value for both vault’s middle position (grid point 41 and gridpoint 52 ). It can be seen that the subsidence quantity gradually increases with computation development, after finally tends to its new balance, both vault’s vertical displacement quantities finally stabilize at about 5.7 mm and the two time process curves are basically consistent.Fig.7 Curves of both vault’s node displacement vs calculation stepsFig.8 shows the time process curves of z -displacement(absolute value) of the monitored grid points around the left tunnel vault when taking the underground water seepage flow intoconsideration. Contrasting with Fig.5 it is obviously seen that the settlement value of 41 grid point is increased and reaches 5.7 mm. And to the other monitored grid points, their subsidence quantities also basically tend to 5.0 mm. The calculation subsidence quantities do not change when their relative positions changes.Fig.8 Time process curves of vault settlement when taking underground water seepage f low into consideration4.3 Comparison of deformation measurement results of surrounding rock In the process of excavating, the Bi Ma-Xi tunnel, the inspecting and consulting company of the fourth investigation and design institute of Chinese Railways Ministry monitored the surrounding rock deformation. Fig.9 shows the monitored vault settlement curves at sections K218+280 and K218+310.#Fig.9 Curves of measured value of vault settlement in process of left tunnel excavationComparing Fig.9 with Fig.5 and Fig.8, the maximal vault settlement calculation value is 3.7 mm when without considering underground water seepage flow, and when taking it into consideration the maximal calculation value is equal to 5.7 mm. And the practical monitored results reach 6.5 mm and tend to be stable after 2 months when the tunnel is excavated. The case fits very well with the coupling analysis result. The vault settlement measurement values in this multi-arch tunnel are all basically leveled off between 5.8 mm and 6.8 mm.The calculation results of coupling fluid-mechanical analysis are slightly smaller than the measured results. The reason is that the numerical calculation is thought as converged when the maximal unbalanced force in surrounding rock tends to a less value after tunnel excavation. And it does not consider the effect of actual time. The parameters in calculating unavoidably exist difference with the parameter of rock mass in reality. These reasons lead to the difference between the coupling analysis and the engineering measurement. But the results obtained in section 4.1 are less than the measuring results considering it indicates that the numerical analysis without underground water seepage flow cannot meet the need of engineering.5 Conclusions1) When underground water seepage flow function is considered in coupling fluid-mechanical analysis, the calculation vault settlements have finally achieved5.7−6.0 mm with the interaction of undergroundwater seepage flow and stress release in surrounding rock around the tunnel. The coupling calculation results are very close to the vault measurement settlement. It indicates that constructing tunnels in aquiferous stratum the underground water seepage flow effect must be considered in the design phase.2) The settlement of the surrounding rock above the tunnel has close relationship with its own position. The region near the tunnel excavation zone has the biggest rock deformation, so it should promptly complete supporting measures. When not considering the seepage flow function, the farther the region, the smaller the rock deformation; but when considering the seepage flow function, the settlement of the surrounding rock is above the tunnel and then basically tends to stable in shallower tunnel and it has obviously influence on the ground surface subsidence.地下水渗流对双连拱隧道围岩变形的影响摘要：一般来说，对于高速公路双连拱隧道，用FLAC3D计算隧道围岩变形时是没有考虑到地下水渗流影响的。
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基于LabVIEW的变速箱故障诊断系统
摘要
这篇论文主要介绍了变速箱的实施过程和设计原理的故障诊断系统，利用虚拟仪器发展中的software-LabVIEW来实现系统的核心设计，通过小波变换和神经网络，通过例子最终验证了该系统的可行性。
1.介绍
作为一个复杂的齿轮机械系统，变速箱有许多特征参数----固定驱动比，大的驱动力矩和紧凑结构。
因此，它通常用来改变转速和转换功率。
与此同时，它是一个容易流失的组件，在过去，Matlab软件编程是为了诊断这样的设备的错误，来分析和处理故障诊断信号，其中的错误位置和故障类型是人工判断的。
这种方法会给变速箱的故障诊断带来人为因素。
这种方法带有局限性，它不容易识别或者是搞清变速箱的故障。
随着计算机技术和机器故障诊断技术的发展，我们提出了一种新思路---基于计算机智能检测的变速箱故障诊断系统，为了提高变速箱故障诊断测量的准确度，快速性，便捷性，和可靠性。
该系统利用小波变换从振动信号中提取参数特点，利用神经网络来得出结论。
这也同时凸显出原检验方法的弱点，分类智能化变速箱的诊断失误。
本文将简要介绍LabVIEW软件尤其是介绍LabVIEW软件的主要问题和情景结构，该系统发展并实现了基于计算机智能检验的变速箱故障诊断系统。
2.总结虚拟仪器的软件开发
虚拟仪器LabVIEW（实验室）是一种发展工程工作台的工作包，虚拟仪器是一种基于G程序（图形语言）由NI（国家仪器公司）一家美国公司提供的。
关于LabVIEW的虚拟仪器的设计能逃避LabVIEW环境。
LabVIEW能够模仿传统仪器上的控制面板，并给出了显示结果，同时还可以以各种形式的计算机显示器显示。
它拥有强大功能的计算器，可以实现信号数据的操作，分析和处理。
此外，它可以完成收集、测量和调节信号I/O接口，从而完成各种测试功能。
在世界上，LabVIEW产品广泛应用与众多领域，例如航空、航天、
通信、汽车半导体和生物医学科学等。
作为一个虚拟仪器，LabVIEW在为工程师们执行自己的思想方面更具有优势,使非专业的程序员更加方便，使得程序与传统的编程工具相比更具可读性，如C、c++、VC + +、VB等。
同时,它具有较强的可扩展性和适应性。
所以在这里我们采用了图形语言LabVIEW来对整个过程的故障进行诊断。
与此同时，LabVIEW通过BP神经网络在转化的振动信号的小波变换和分类信号特性方面更具创造性。
更重要的是,它为故障诊断变速箱提供了一种全新的设计手段。
3.基于LabVIEW变速箱DIAGNOISIS的系统故障
A.变速箱故障诊断系统的结构与构成
变速箱故障诊断系统采用微量和数字传输序列的框架结构来完成故障诊断，包括训练部分和审查部分。
图1显示的是框架体系。
训练部分
审查部分
图1 系统的框架体系
在训练部分中,首先,变速箱中典型的故障信号的输入到系统，然后在LabVIEW中选择合适的小波变换基础,利用小波工具来分析信号,一些频率的特征参数被挑出并且加以规范化后，将会通过全局变量被输入到LabVIEW中的BP训练网络,最后一致的重量和阈值获得和诊断网络结构经训练BP神经网络后得加以确定。
在审查部分，采集到的故障信号通过A/D转换输入到计算机。
利用小波理论的LabVIEW工具提取的特征参数，为了要得到变速箱的故障类型，，归一化的结果将会被输入到已训练的BP神经网络加以识别和诊断变速箱的故障。
B.主要技术问题的实现和它们的设置
从图１中显示的系统框架来看，有一些技术问题。
如下所示：
1)从故障信号提取和归一化的特征参数。
2)从神经网络提取的重量。
3)固定网络的故障诊断。
上述问题涉及LabVIEW 的多种风格，接下来，我们来具体描述它们的设置：
1) 小波变换和规范化过程
该系统通过Lab 使用的小波工具,来实现小波变换,提取特征参数信号。
前面板和程序框图中可以在图2中看到。
该系统对故障信号用小波的工具包分解到N 层，获得一组低频信号与N 组高频信号然后获得高频系数权重的高频信号
12{,,,}n d d d Λ。
假定E.j 是jth 层高频系数串行d.j 的能量，这里
21n
j i i E X ==∑
其中n 是d.j 权重的数量。
全层高频系数的能量可以通过以上的计算得到。
经过归一化后全层高频系数的能量，形成的向量是我们所需要的特征参数。
图2 小波变换的前面板和系统框图
2) BP 神经网络的训练
利用在LabVIEW 中的阵列控制器与神经网络算法,该系统可以实现BP 神经网络的训练,获得对故障诊断的权重。
图3为显示面板。
本系统采用三层BP 神经网络规范。
输入层N 的数目是小波分析层的数目输出层M 的数目是齿轮箱故障类型的数目。
隐藏层H 的数量是无限的；它是由输入层和输出层的数目决定的。
我们经验公式得到方程
H l =+。
l 是一个范围为１-10的整数。
输入层、输出层和隐藏层的代码号分别是7、10、4。
图3 训练网络的前面板
BP 神经网络的典型的故障识别训练有素的。
系统的输入向量为变速器的
故障信号的特征矢量。
输出向量是齿轮箱故障类型。
根据BP算法,系统利用实验样品、增益权重和阈值，从输入层、隐藏层和隐藏层到输出层训练网络,来满足整个网络的误差要求。
曲线可以显示不同的变化的趋势。
图4 BP神经网络的程序框架
3)BP神经网络的应用
BP神经网络的应用是选择后的网络的故障识别。
它是由LabVIEW算法实现的。
运用增重到网络以识别信号，得到故障类型。
这个程序框架显示在图4中。
此部分为实现变速箱故障诊断的重要过程。
它实时读取特征参数，并利用用于实时训练的BP神经网络识别，获取最后的故障类型。
这是BP网络的一个标准的动态计算过程。
4.变速箱故障诊断的实例
在实例中,小波变换选择小波DB2作为基本小波，它在第七层。
小波变换DB2是一种正交的变换。
有几个故障类型，如齿轮断裂、点蚀、磨损与崩溃。
首先我们固定输入层，输出层和隐藏层的数目分别为7、10、4，假设故障是侵蚀的,利用这个系统完成振动信号采集，然后提取信号的特征参数，最后通过训练BP神经网络得出结论。
图5显示了这个系统前面板的结论区。
图5 前面板的结论区
通过结论部分的主要界面，我们可以看到齿轮断裂、腐蚀、磨损、碰撞和错误的结论的坐标数据点。
结论是按照预测进行的，所以它演示了该系统的可行性和有效性。
5.结论
该系统基于LabVIEW，利用小波变换融合算法提取振动信号的特征参数。
然后它用神经网络来判断，并得出结论。
整个诊断系统应用了信号小波变换，BP神经网络与数据采集，数据辨识、贮存等,实现实时数据采集和故障类型的识别。
本系统的优点:
从信号处理方面来看，它完成信号特征参数的提取，并使用先进的方法来保证系统的精密、便利和信誉。
从系统的总体结构来看，它利用LabVIEW来产生系统，使得软件变成硬件替代。
这里是一个突破。
这样一来，它提高了结构的安全性和可靠性。
进而，在应用和扩展时将更加方便。
该系统的应用将会为复杂仪器提供一个新的故障诊断技术路径，并且为将来的发展将创下一个新的空间。