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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。

毕业设计外文翻译_英文版

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.。

本科毕业设计外文翻译(中文)

本科生毕业设计（论文）外文翻译外文原文题目：Real-time interactive optical micromanipulation of a mixture of high- and low-index particles中文翻译题目：高低折射率微粒混合物的实时交互式光学微操作毕业设计（论文）题目：阵列光镊软件控制系统设计姓名：任有健学院：生命学院班级：06210501指导教师：李勤高低折射率微粒混合物的实时交互式光学微操作Peter John Rodrigo Vincent Ricardo Daria Jesper Glückstad丹麦罗斯基勒DK-4000号，Risø国家实验室光学和等离子研究系jesper.gluckstad@risoe.dkhttp://www.risoe.dk/ofd/competence/ppo.htm摘要：本文论证一种对于胶体的实时交互式光学微操作的方法，胶体中包含两种折射率的微粒，与悬浮介质（0n ）相比，分别低于（0L n n <）、高于（0H n n >）悬浮介质的折射率。

球形的高低折射率微粒在横平板上被一批捕获激光束生成的约束光势能捕获，捕获激光束的横剖面可以分为“礼帽形”和“圆环形”两种光强剖面。

这种应用方法在光学捕获的空间分布和个体几何学方面提供了广泛的可重构性。

我们以实验为基础证实了同时捕获又独立操作悬浮于水（0 1.33n =）中不同尺寸的球形碳酸钠微壳（ 1.2L n ≈）和聚苯乙烯微珠（ 1.57H n =）的独特性质。

1 引言光带有动量和角动量。

伴随于光与物质相互作用的动量转移为我们提供了在介观量级捕获和操作微粒的方法。

过去数十年中的巨大发展已经导致了在生物和物理领域常规光学捕获的各种应用以及下一代光学微操作体系的出现[1-5]。

毕业设计英文翻译原文

Highway Subgrade Construction in Expansive Soil AreasJian-Long Zheng1Rui Zhang2and He-Ping Yang31 Professor and President, ChangSha Univ. of Science and Technology, Chiling Road 45, Changsha, Hunan 410076, China. E-mail: zjl_csust@2 Ph.D. Candidate and Lecturer, School of Highway Engineering, ChangSha Univ. of Science and Technology, Chiling Road 45, Changsha, Hunan 410076, China. E-mail: zr_csust@3Professor, School of Highway Engineering, ChangSha Univ. of Science and Technology, Chiling Road 45, Changsha, Hunan 410076, China. E-mail: cscuyang@(Accepted 22 May 2007)IntroductionExpansive soil is predominantly clay soil that undergoes appreciable volume and strength changes following a change in moisture content. These volume changes can cause extensive damage to the geotechnical infrastructure, and the damage is often repeatable and latent in the long term (Liao 19848). China is one of the countries with a wide distribution of expansive soils. They are found in more than 20 provinces and regions, nearly 600,000 km2in extent. It has been estimated that the planned highways totaling 3,300 km in length pass through expansive soils areas (Zheng and Yang 200422). Improper highway construction in such areas could well lead to great losses and damage to the environment.In 2002, the Chinese Ministry of Communications (CMOC) sponsored a research project, “A Complete Package for Highway Construction in Expansive Soil Areas,” whose primary objective was to solve expansive soil problems in highway engineering. A research group with personnel from Changsha University of Science and Technology (CUST) was set up. Comprehensive laboratory tests, field investigations, and analyses were carried out, aimed at solving highway engineering problems in several different expansive soil areas. A complete presentation of the results of this research is beyond the scope of this paper, but the research on subgradeconstruction for the Nanning to Youyi Guan (NanYou) highway will be discussed to introduce the laboratory studies performed on soil properties, classification of swelling potential, and engineering properties of expansive filler soils. Field investigations of slope failures in the Ningming area also will be described. Several new techniques for building embankments and treating expansive soil cut slopes also are presented.Site GeologyNingming Basin lies in south China. The region has in an oceanic monsoon climate with long summers and quite short winters. The annual average temperature is 22.1° centigrade and the annual rainfall is about 1,200 mm, falling mostly from April to August. There is a very obvious difference between the rainy and dry seasons. The Ningming Basin is an east–west tectonic faulted basin formed in Q2–4, with deposits of lacustrine mudshale from the Nadu formation (N y) of the Eocene, 1,500 m in thickness. Argillaceous siltstone and little siltstone are present as well. The obliquity of the stratum is about 5°–7°in the middle of the basin, but 22°at the edge. In addition, there are Jurassic and Triassic siltstone and limestone around the basin.A typical geological profile from the Ningming area is shown in Fig. 1. Ningming expansive soils, dark or light gray in color, are of residual origin from the weathering of mudshale or shale from the Nadu formation of the Eocene. Due to the parent rock’s structure, the residual expansive soils have a residual fabric (microbedding and tiny tectonic fissures) originating from the parent rock, and many included ferromanganese nodules. The weathered mudshale, once exposed, collapses rapidly into smaller prism-shaped fragments, which can continue to fragment into smaller and smaller pieces. A great many vertical, cross and horizontal tectonic joints, tectonic fissures, and weathered fissures clearly can be seen in excavated profiles, and a soft interlayer exists between the soil and mudshale layers. The active zone, about 3-m thick (CMOC 1996b10) is several meters below the surface, but nevertheless affected by seasonal climatic changes (Nelson and Miller 199213).Research on Embankment Construction and Its Engineering ApplicationIn expansive soil areas, embankments filled with expansive soils usually encounter nonuniform settlement (Hu et al. 20044). Road shoulders, which cannot be compacted, adequately, develop large longitudinal cracks, and large wave deformations appear along the cross section. The bearing capacity of the pavement decreases substantially as a result of the reduced resilient modulus of the subgrade, and slope surface failures usually occur. Embankment failures usually involve three phases: shrinkage cracks form in the slope during the dry season; water infiltrates into the soil mass through the cracks in the subsequent wet season, with soil swelling; and finally, the shear strength of the clayey soil deteriorates to the extent that the shear forces within the slope cannot be adequately resisted, resulting in a localized slope failure. Generally, times until failure can range from several months to several years (Zhang et al. 2005).Selection of Embankment FillerIt has been stipulated in China’s Technical Specification for the Construction of Highway Subgrades (CMOC 1996a11) that expansive soil with a high swelling potential should not be used as embankment fill material due to its poor water stability. Expansive soil with medium swelling potential can be used as filler only after it has been improved. Expansive soil with low swelling potential can be used as filler according to the climate, hydrological conditions, and the highway classification, but the side slopes and top of the embankment should be protected. In light of these specifications, nearly five million m3of expansive soils and highly weathered mudshale excavated for the construction of the NanYou highway in the Ningming area could not be used as embankment filler without being improved, because they are characterized as having moderate swelling potential.Consequently, the research group studied stabilizing expansive soils with calcium lime, Portland cement, and mixtures of lime and cement in the laboratory. The resulting clay contents, compressibility, California bearing ratio (CBR), and swelling capabilities showed that the improving effect of the lime was the greatest (Chen 20042). For light-gray expansive soil, the optimum lime content was determined to be 3%, and the optimum moisture content was 15.2%. These values were determined by compaction tests at 2,684.9 kj/m3. The resulting CBR and soakedswelling ratio satisfied the specifications for fill. However, in practice it is very hard to mix lime and expansive soil properly because the natural moisture content of the soil is so very high. The soil easily agglomerates, so the operation is complicated and requires heavy construction machinery. In addition, the high price of lime will greatly increase highway construction costs, and lime dust that inevitably escapes during spreading will do some harm to the environment. Therefore, lime stabilization is not popular in engineering practice. However, if the expansive soils must be replaced by nonexpansive material transported from several hundred kilometers away that would entail high costs and environmental degradation.According to the Chinese specification, the CBR of fill in an upper embankment (less than 1.5 m below the embankment surface) should reach 4%, and it should be 3% for the material in the lower embankment (more than 1.5 m below the surface). In light of the routine soaking that is part of the CBR test method, the CBR of expansive soils can rarely reach 3%. However, according to the change of CBR with moisture content (Fig. 3), and the change in swell percent of CBR samples with time , the research group found that if the CBR samples were not soaked, the CBR was very high at relatively low moisture content. Therefore, research was carried out on the feasibility of using expansive soils as fill, including research on evaluating their bearing capacity and the field compaction control of expansive soil fill.Changes in California bearing ratio with moisture contentEvaluating the Bearing Capacity of Expansive SoilsSubgrade “stiffness” controls the total pavement thickness, especially with flexible pavements. So, it is very important to correctly test the stiffness of subgrade materials, and the conditions (density and moisture content) at which the material is tested should be considered. The CBR testing condition stipulated in China’s Test Methods of Soils for Highway Engineering (CMOC 1996b) involves compacting the material in a mold (0.152 m in diameter and 0.120 m high) and soaking for 4 days under a surcharge weight of 50 N, corresponding to 2.7 kPa. However, for clayey materials, this procedure leads to only the upper and lower parts of the sample becoming saturated or nearly saturated, because of the low permeability of clay, especially for expansive soils, and the air entrapped in the sample. The measuredCBR then only corresponds to the saturated soil in the shallow upper part, where the soil has disintegrated under the light surcharge after soaking (Uzan 1998).However, suppose expansive soil is used as fill in the lower embankment and nonexpansive fill material is used in the upper as a moisture barrier. Then, the surface of the lower embankment would not be soaked, and the upward pressure on the surface would no longer be 50 N. Therefore, the research group studied a modified CBR test on expansive soil simulating such field conditions. The study mainly focused on weathered mudshale, whose swell potential is medium, and which formeda large percentage of excavated material in the construction of the NanYou Highway.1.Li, S. L., Qin, S. J, and Bo, Z. Z. (1992). Studies on the engineering geology of expansive soils in China, Jiangsu Science and Technology Publishing House, Nanjing, China, 212.2.Liao, S. W. (1984). Expansive soil and railway engineering, Chinese Railway Publishing Press, Beijing, 374.3.Mao, Y. C. (2006). “Tests on the feasibility of using expansive soil as embankment fill.” MSc thesis, Changsha Univ. of Science and Technology, Changsha, China.4.Ministry of Communications of the People's Republic of China (CMOC). (1996a). Technical specifications for the construction of highway subgrades JTJ033-95., Renmin Communication Press, Beijing.5.Ministry of Communications of the People's Republic of China (CMOC). (2003). Specifications for the design of highway subgrades JTJ013-2002, Renmin Communication Press, Beijing, 156.6.Ministry of Communications Second Highway Survey Design and Research Institute of China (CMOC). (1996b). Handbook of design for highway subgrades, 2nd Ed., Renmin Communication Press, Beijing, 407.7.Uzan, J. (1998). “Characterization of clayey subgrade materials for mechanistic design of flexible pavements.” Transportation Research Record. 1629, National Research Council, Transportation Research Board, Washington, D. C., 188–196.8.Wei, T. Z. (1990). “Some factors influencing on deformation of foundation on expansive soil in Guangxi.” Proc., 1st Chinese Symp. on Expansive Soils, Southwest Jiaotong University, Chengdu, 232–238.9.Yang, H. P. (1999). “Approach to strengthening expansive soil embankment side slope with geogrid.” Chinese J. Highw., 16(3), 42–46.10.Yang, H. P., Qu, Y. X., and Zheng, J. L. (2005). “New developments in studies of Ningming expansive soils.” Chinese J. Geotech. Eng., 17(9), 981–987.。

江苏大学机械毕业设计外文翻译

江苏大学机械毕业设计电磁阀外文翻译附录Ⅰ：Magnetoelastic Torque Sensor Utilizing a Thermal Sprayed Sense-Element for Automotive Transmission ApplicationsBrian D. KilmartinSiemens VDO Automotive Corporation ABSTRACTA Magnetoelastic based Non-Contacting, Non-Compliant Torque Sensor is being developed by Siemens VDO for automotive transmission applications. Such a sensor would benefit the automotive industry by providing the feedback needed for precise computer control of transmission gear shifting under a wide range of road conditions and would also facilitate cross-platform usage of a common transmission unit.Siemens VDO has prototyped transmission torque sensors operating on the principle of Inverse- magnetostriction, also referred to as the Inverse-Joule Effect and the Villari Effect. Magnetostriction, first documented in the mid 1800’s, is a structural property of matter that defines a m aterial’s dimensional changes as a result of exposure to a magnetic field. Magnetostriction is caused when the atoms that constitute a material reorient in order to align their magnetic moments with an external magnetic field. This effect is quantified for a specific material by its saturation magnetostriction constant, which is a value that describes a material’s maximum change in length per unit length.Inverse-magnetostriction, conversely, defines changes in a material’s magnetic properties in response to applied mechanical forces. Material that is highly magnetostrictive and elastic in nature is referred to as being magnetoelastic. The premise of the Siemens VDO torque sensor design is that a magnetoelastic material can be bonded to a cylindrical shaft and magnetized in its mechanical quiescent state to create a sense- element. While under torque, principle tensile and compressive stress vectors in the form of counter- spiraling, mutually orthogonal helices develop in the shaft and are conveyed to the magnetoelastic sense-element giving rise to a measurable magnetic field change. The magnetic field deviation that arises from the magnetoelastic sense-element is directly proportional to the magnitude of the imposed torque. In effect, the magnetic field is modulated by torque. A sensitive magnetometer then translates the field strength into an analog voltage signal, thereby completing the torque-to-voltage transducer function.Critical to the success of the Siemens VDO torque sensor design is an intimate attachment of the sense- element to the torque-bearing member. Inconsistencies in the boundary between the sense-element and the torque-bearing member will result in aberrant coupling of stresses into the sense-element manifesting in performance degradation. Boundary inconsistencies can include such imperfections as voids, contaminates, lateral shearing, and localized zonesof stress pre-load. Such inhomogeneities may be inherent to an attachment method itself or may subsequently be caused by systemically rendered malformations.Thermal spray, the process where metal particles are deposited onto a substrate to form a coating, was used to address the issue of securely affixing magnetic material to a torque-bearing member. In addition to achieving the prerequisite of an intimate and secure bond, the thermal spray process can be regulated such that the deposited magnetic material is pre-loaded with the internal stresses needed to invoke the inverse- magnetostriction effect.Summarizing, the passive nature of the magnetic sense- element provides an intrinsically simple kernel for the Siemens VDO torque sensor that makes for a highly reliable and stable design. The thermal spray process adds robustness to the mechanical aspect by permitting torque excursions to an unprecedented ±2000% of full scale (per prototype validation testing of certain constructs) without the need for ancillary torque limiting protection devices. Furthermore, accuracy, repeatability, stability, low hysteresis, rotational position indifference, low cost and amenability to the high-volume manufacturing needs of the automotive marketplace are all attributes of this torque sensing technique. When coupled with a magnetometer that is grounded in well- established fluxgate technology, the resultant sensor is inherently dependable and can potentially establish a new standard for torque measuring sensors.INTRODUCTIONAs is well known, automotive transmissions are designed to alter the power transfer ratio between the engine and the drive wheels effectively optimizing engine loading. The engine thereby runs in a narrow and efficient operating band even though the vehicle travels over a wide range of speeds. For automatic transmissions, shift valves select the gear ratio based generally on the throttle position, engine vacuum and the output shaft governor valve state. With the advent of electronic sensors and computerized engine controllers, transmission shift functions have been migrating towards closed-loop operation under software processing control. Along with this progression came the realization that the transmission output torque would provide a valuable feedback parameter for shift and traction control algorithms. The measurement of output torque, however, proved elusive due to the extremely harsh operating conditions. One particular SUV application under consideration required 1% accuracy in measurements of roughly 2700 Nm with possible torque excursion of 4700 Nm; all while exposed to temperature extremes -45 to +160 o C.One method for measuring torque is to examine the physical stresses that develop in a shaft when it is subjected to an end-to-end twisting force. The principle stresses are compressive and tensile in nature and develop along the two counter-spiraling, mutually orthogonal 45 o helices. They are defined by the equation :t = Tr / JWhere T is the torque applied to the shaft, r is the shaft radius and J is the polar moment of inertia.Setting p r4/ 2 = J for a solid cylindrical shaft and r = d/2 yields:t = 16T / p dOnce again, T is the torque applied to the shaft and d is the shaft diameter.Furthermore, the degree of twist experienced by the shaft for a given torque is given by2: q = 32(LT) / (p d4G)Where L is the length of the shaft, T is the applied toque, d is the diameter of the shaft and G is the modulus of rigidity of the shaft. The modulus of rigidity defines the level of elasticity of the shaft material, thus, a lower G value would manifest in a shaft with a higher degree of twist for any given applied torque.Torque induced stresses that occur in the shaft material are transferred into an affixed magnetic coating and give rise to measurable changes in its surrounding magnetic field that are directly proportional to the magnitude of the applied torque; with the polarity of the magnetic field, i.e., north or south, governed by the direction of the applied torque. In essence, this is the premise of torque sensing by means of inverse magnetostriction.TORQUE SENSOR EMBODIMENTTo effectively invoke the inverse-magnetostriction effect, the magnetic material must be correctly pre-loaded with stress anisotropy in its quiescent state. In the case of a cylindrically shaped magnetic element, the anisotropic forces must be circumferential (i.e., tangential) in nature and can be either compressive or tensile –depending on the polarity or sign of the material’s saturation magnetostriction constant. Achieving a homogenous pre-load throughout the magnetic material is crucial if the sensor is to accurately interpret torque regardless of its rotational position within a stationary magnetometer.POSITIVE MAGNETOELASTIC DEVICESEarlier efforts to create such a torque sensing element relied on a sense element made of material with a positive saturation magnetostriction constant. This embodiment was realized with a ring-shaped magnetoelastic element made from 18% nickel-iron alloy that intrinsically requires tensile circumferential pre- loading 3 . Such a pre-load was achieved by pressing the ring onto a tapered area of the base shaft – effectively stretching it. The effect of tensile stress on the magnetic hysteresis behavior is shown in Figure 1 where the remnant inductance, B r , nearly triples. The “easy-axes” of the magnetic domains align circumferentially due to the anisotropy defined by the principal tensile stress vector. When magnetically biased, the system in effect operates as a circumferentially shorted magnet with B approaching B r and H approaching zero.NEGATIVE MAGNETOELASTIC DEVICESTo advance the state of the art, Siemens VDO Automotive has opted for a magnetoelastic element witha negative saturation magnetostriction constant. In this case, the alloy is very high in nickel content exhibiting a saturation magnetostriction, l s , in the range of -3e-5 dl/l and requires the stress pre-load to be tangentially compressive in nature. To achieve this embodiment, the magn etoelastic material that constitutes the sense element is “deposited” onto the base shaft using a high- velocity-oxygen-fuel (HVOF) thermal spray process. The coating thickness is only 0.5mm with an axial length of 25mm. The sense element material is endowed with compressive stress by means of precise control of the thermal spray process parameters. This proprietary procedure transforms a deposition process that normally confers isotropic material properties into one that renders the requisite stress anisotropy.Prototype FabricationMagnetoelastic ElementThe specification for the shaft requires the measurement of torque levels of 2700 Nm with no deleterious effects following exposures of up to 4700 Nm. Operating temperature is -45 o C to 160 o C.By c onverting from the earlier torque sensor “pressed-on ring” concept to one based on a magnetoelastic material with a negative saturation magnetostriction constant, l s , the design is advanced in several respects. Primarily, its resiliency against stress/corrosion cracking is enhanced by 1) the inherent insusceptibility of high nickel content alloys towards corrosives and 2) by the lower porosity of material in compression. This is in distinct contrast with the high iron content ring placed in tension which is vulnerable to fissuring, material creep and stress corrosion cracking which can, over time, relieve the necessary anisotropic forces causing performancedegradation.An important consequence of using the thermal spray technology is the intimate bond provided between the deposited magnetoelastic element and the base shaft. By using a thermal spray process, the boundary whereby torque induced stresses are transferred is free of such imperfections as voids, galled or furrowed material and localized stress gradients that are all characteristically associated with the pressed-on ring technique. These imperfections can induce aberrations in the magnetic field shape thereby imparting torque measurement errors relative to the rotational position of the shaft with respect to a stationary magnetometer. Furthermore, the strong bond at the interface effectively eliminates the slippage commonly associated with the interference fit of a pressed-on ring during extreme torque exposures. Any movement at this interface will manifest as a biasing of material stresses causing a zero-shift measurement error. This is not a concern when the magnetoelastic element is deposited using an HVOF thermal spray gun. Torque excursions to an unprecedented ±2000% of full scale have been successfully applied directly to prototype sensors without ancillary torque limiting protection devices.In addition, depositing the magnetoelastic element onto a rotating shaft provides an inherently mechanically balanced assembly that imposes no angular velocity (RPM) or angular acceleration limits on the system.Other thermal spray technology attributes are its amenability to high volume manufacturing environments, the robustness of the process insuring consistent reproducibility, and an overall reduction in fabrication steps –such as the elimination of machining procedures to mass-produce rings, cutting operations for precisely matching tapers on the shaft and ring, and pressing operations to install rings onto shafts.Magnetic Field ShapingContributions from the mechanical mounting tolerances of system components (e.g., bearings and bushings) can manifest as a misalignment between the centroid centerlines of the magnetometer and the magnetoelastic element. Once calibrated, any displacement in the positional relationship between these two components will alter the system’s transfer function, possibly causing the overall error to exceed specification. The sharply focused nature of the magnetic field radially emanating from the magnetoelastic element during the application of torque (see Figure 3) accentuates this effect. This error can be minimized by shaping the physical structure of the magnetoelastic element resulting in a contouring of the magnetic field to a more favorable shape. As shown in Figure 4, the magnetic field is made to be less pronounced with an hourglass shaped magneto elastic element and sensitivity to misalignment is, thus, reduced. In this example, the magneto elastic element is contoured such that the air gap between the magneto elastic element and the magnetometer is reduced when axial displacement between their centroid centerlines occurs. The expected reduction in magnetic signal strength caused by this displacement is thus compensated by the air gap reduction.Shafts can be fabricated with a variety of contoured surface adaptations and the thermal sprayed magnetoelastic element’s shape will expectedly follow suit. As is evident, a pressed-on ring manifestation of the magnetoelastic element would be incompatible with this technique. Various contours are being considered for further reducing the sensitivity to misalignment and for improving other performance parameters such as magnetic field strength and hysteresis.Cylindrical Shaft Shown with Superimposed Associated Magnetic Field (i.e., Radially Directed Flux Density)Contoured Shaft (Hourglass Shape) Shown with Superimposed Associated Magnetic Field (i.e., Radially Directed Flux Density)In Figures 3 and 4, the spatial image of the shaft is mapped using a laser displacement system and the superimposed magnetic field is mapped in 3-space with a hall cell.MagnetometerRounding out the torque sensor hardware complement is a non-contacting magnetometer that translates the magnetic signal emitted by the shaft’s sense element into an electrical signal that can be read by system-level devices. Coupling the torque signal to some interim conditioning electronics magnetically is an attractive op tion due to its “non-contacting” attribute. A signal transference scheme capable of spanning an air gap is advantageous sinceit requires no slip rings, brushes or commutators that can be affected by wear, vibration, corrosion or contaminants.The fundamental magnetometer embodiment, shown in Figure 5, is circular with the shaft passing through its center. The magnetometer encompasses the magnetoelastic element of the shaft and the shaft is allowed to freely rotate within the fixed magnetometer. Power and the output signal pass through the magnetometer’s wiring harness.Transmission Torque Sensor MagnetometerThe magnetometer actually performs several functions beyond measuring a magnetic field’s strength. These functions include magnetic signal conditioning, electrical signal conditioning, implementation of self-diagnostics, and the attenuation of magnetic and electromagnetic noise sources.The magnetic detection method chosen for the torque sensor is fluxgate magnetometry, also known as saturable-core magnetometry. This is a well-established technology that has been in use since the early 1900’s. Fluxgate magnetometers are capable of measuring small magnetic field of strengths down to about 10 -4 A/m (or 10 -6 Oe) with a high level of stability. This performance is roughly three orders of magnitude better than that achieved by Hall Effect devices. Although many fluxgate designs use separate drive and pickup coils, the torque sensor magnetometer was designed to use a single coil for both functions.Magnetic signal conditioning is accomplished by use of flux guides integral to the magnetometer. These flux guides amplify the magnetic signal radiating from the shaft’s sense element prior to detection by the fluxgates thereby improving the signal-to-noise ratio. The flux guides provide additional signal conditioning by integrating inhomogeneities in the magnetic signal relative to the shaft rotational position that might otherwise be misinterpreted as torque variations. The flux guide configuration is shown in Figure 6 and a magnetic simulation of the resulting field concentration is shown in Figure 7.Flux guides surrounding magnetoelastic elementAxial view of magnetic simulation with flux guide material’s relative DC permeability set to 50,000 (e.g., HyMu “80”)To further improve the magnetometer’s immunity to stray signals present in the ambient, common-mode rejection schemes are employed in the design of both the electronic and magnetic circuits. For example, wherever possible, differential circuitry was used in theelectronic design in order to negate common-mode noise. This practice was carried over to the magnetic design through the use of symmetrically shaped flux guides and symmetrically placed fluxgates that cancel common- mode magnetic signals that originate outside the system.Finally, to augment the electrical and magnetic common- mode rejection strategies, EMI and magnetic shielding practices were incorporated into the design to further improve the signal-to-noise ratio. Stray magnetic and electro-magnetic signals found in the ambient are prevented from reaching the fluxgates and the shaft’s magnetic torque-sensing element through the use of shielding material that encompasses these critical components.The functional diagram of Figure 8 depicts the concept of the magnetometer by showing a simplified version of the circuitry with extraneous components removed for additional clarity. An application specific integrated circuit (ASIC) contains all the circuitry necessary to perform the indicated functions.Magnetometer Functional DiagramSummarizing, the multi-function, fluxgate based magnetometer design provides the optimal platform for detecting the modulated magnetic field that emanates from the shaft’s torque-sensing magnetic element. By coupling time-proven fluxgate technology with an innovative flux guide configuration and with sophisticated electronic circuitry, the resultant magnetometer is durable, accurate, and stable and comprehensively achieves the design goals dictated by the application.CONCLUSIONThe latest developments in the magnetoelastic torque sensor that are presented here advance the current state of the technology by addressing many obstacles that have delayed itsacceptance by the automotive industry. Thermal spray deposition of the magnetoelastic element has resolved problems that have plagued earlier versions of the magnetoelastic torque sensor’s active element. The lack of integrity of the shaft/magnetoelastic element interface, stress-corrosion cracking, long term stability, inhomogeneity of magnetic properties and manufacturing processes that run counter to high volume production, are no longer hindering the introduction of magnetoelastic torque sensors into the automotive marketplace. With design goals clearly defined and an aggressive development program invariably progressing, the prospect of an automotive, magnetoelastic based non-compliant torque sensor is now more readily attainable.ACKNOWLEDGMENTSI would like to acknowledge the efforts of Ivan Garshelis who pioneered this approach to torque sensing and who had the unwavering vision to recognize this technology’s potential; and Carl Gandarillas whose scientific and analytical investigative approach has explicated much of the mystery associated with thermal sprayed magnetics. I would also like to express my gratitude to the torque sensor development team at Siemens VDO Automotive for their dedication and the extra effort that they put forth; and to Siemens VDO Automotive management for having the courage to invest in a new technology and the patience to see it through.REFERENCES1. Raymond J. Roark and Warren C. Young, Formulas for Stress and Strain, 5 th Edition, McGraw-Hill; Chapter 9, Torsion2. Stephen H.Crandall and Norman C. Dahl, An Introduction to the Mechanics of Solids, McGraw-Hill; Chapter 6, Torsion3. Ivan J. Garshelis, Magnetoelastic Devices, Inc., IEEE Transaction On Magnetics ; 0018-9464/92 V ol. 28, No. 5 September 5, 1992ADDITIONAL SOURCES1. Richard L. Carlin, Magnetochemistry; Springer-Verlag2. Rollin J. Parker, Advances In Permanent Magnetism; John Wiley & Sons3. Etienne du Tremolet de Lachhesserie, Magnetostriction Theory and Applications of Magnetostriction; CRC Press4. Richard M. Bozorth, Ferromagnetism; IEEE Press附录Ⅱ：磁力矩传感器利用一个热喷涂感知元件在汽车变速器中的应用转载自：2003年发动机电子控制布赖恩D.基尔马丁西门子威迪欧汽车电子公司摘要一个非接触式的，非兼容扭矩的传感器是由西门子VDO正在开发应用于汽车传动之中。

毕业设计英文翻译解读

金刚钻的工业化运用一个程序一般需要50至70美网。

在这样的切割频率下，工具的负载量是比较低的。

而欧洲这样的程序下金刚钻的模型是完全不一样的！在我国，在这样的程序下，普遍金刚钻工具在非常自由的切割条件下，产品是不规则的易碎的微粒！在欧洲因为各种因素，情况是不同的。

因为欧洲的生活水平远高于我国，因此，他们的劳动力成本也要高。

为了使欧洲最大的石材生产商保持竞争力，他们必须要把注意力从原材料转移到生产的有效输出和最大化输出。

这就要求产品从原材料到成品的生产过程中尽可能减小能源的耗费和不必要的浪费。

该方法需要机床技术能够高速运作和先进的加工，可进行可靠的长时间持续的，无人值守操作。

在20世纪90年代，在机械和金刚石工具技术方面有很大的发展，使产量增加和降低生产成本。

如果我们对比一下欧洲和中国生产标准，我们可以看到在机器和工具的生产方面，中欧存在很大的差距。

在欧洲，制造这些瓷砖几乎是完全自动的，因为高效率的机械设计和自动处理设施。

最新一代的锯床这种应用能够使用主轴高达80分直径锯片。

机器和工具的设计，在达到下列的参数下，切割率是可以更快的。

•表面速度：- 25 – 35m / s•切削深度：-1mm•大桥速度：- 17m/min•切割速度：- IPOcm/5min或1m/h每个刀片•机输出：- 640m/5day（8小时每天）在这样的条件下，生产浪费减至最低，产量确更高。

通常情况下，在欧洲，刀片会产生10mm的缺口，而中国有12mm。

并且相对于中国12-15mm的切面的切口，欧洲只有10-12mm的切口。

在实现生产最大化材料处理和优化加工时间也是关键，厚片的切据被自动转移到自动的二次加工。

在这样精确的切割率下，对于金刚钻工具的要求是很高的，在程序控制下，型号和尺寸与中国的标准下是有很大不同的。

由于切割率相对高很多，最通常的尺寸是30-50。

切割率高，意味着工具的负载量也高，金刚钻的性质也会不一样！金刚钻的要求一般都是统一的，强大，块状颗粒，这是使在长时间的高负荷下，保持高产量。

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。

软件工程专业毕业设计外文文献翻译

考虑翻译工具的易用性和价格
引用文献：确保引用的外文文献来源可靠、准确翻译准确：保持原文意思不变，语言流畅自然格式规范：遵循学术论文的格式要求，包括标题、作者、摘要、关键词等文献整理：对外文文献进行分类整理，方便查阅
校对：检查语法、拼写和标点错误修改：调整句子结构、替换用词，提高表达准确性和流畅性对照原文：确保准确传达原文意思团队协作：多人合作，互相校对和修改
软件工程外文文献翻译的技巧
掌握专业术语和常用表达方式理解原文的语境和语义注意原文的语气和修辞结合上下文理解原文的含义
掌握专业术语：熟悉软件工程领域相关术语，确保翻译准确。
句式结构清晰：合理安排句子结构，使译文流畅易懂。
语义连贯：保持译文语义连贯，避免出现歧义或理解困难。
智能编辑：对机器翻译结果进行智能优化，减少人工干预
跨语言信息检索：利用人工智能技术快速查找和获取外
文文献资源
全球化推动跨文化交流的发展
人工智能技术在跨文化交流中的应用与前景
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软件工程外文文献翻译在跨文化交流中的作用
跨文化交流中语言翻译的挑战与机遇
人工智能与机器学习在软件工程中的应用
语境理解：外文文献中的语境和中文可能存在差异，需要准确理解原文的语境和含义，并进行适当的翻译。
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文化背景：不同国家和地区的文化背景、历史传统、价值观念等可能存在差异，需要对外文文献中的文化元素进行适当的解释和调整。
专业知识：软件工程领域涉及的专业知识较多，需要对外文文献中的相关内容进行深入理解和翻译，以确保准确性和专业性。

毕业设计(论文)外文翻译

华南理工大学广州学院本科生毕业设计（论文）翻译外文原文名Agency Cost under the Restriction of Free Cash Flow中文译名自由现金流量的限制下的代理成本学院管理学院专业班级会计学3班学生姓名陈洁玉学生学号200930191100指导教师余勍讲师填写日期2015年5月11日外文原文版出处：译文成绩：指导教师（导师组长）签名：译文：自由现金流量的限制下的代理成本摘要代理成本理论是资本结构理论的一个重要分支。

自由现金流代理成本有显着的影响。

在这两个领域相结合的研究，将有助于建立和扩大理论体系。

代理成本理论基础上，本研究首先分类自由现金流以及统计方法的特点。

此外，投资自由现金流代理成本的存在证明了模型。

自由现金流代理成本理论引入限制，分析表明，它会改变代理成本，进而将影响代理成本和资本结构之间的关系，最后，都会影响到最优资本结构点，以保持平衡。

具体地说，自由现金流增加，相应地，债务比例会降低。

关键词：资本结构，现金流，代理成本，非金钱利益1、介绍代理成本理论，金融契约理论，信号模型和新的啄食顺序理论，新的资本结构理论的主要分支。

财务con-道的理论侧重于限制股东的合同行为，解决股东和债权人之间的冲突。

信令模式和新的啄食顺序理论中心解决投资者和管理者之间的冲突。

这两种类型的冲突是在商业组织中的主要冲突。

代理成本理论认为，如何达到平衡这两种类型的冲突，资本结构是如何形成的，这是比前两次在一定程度上更多的理论更全面。

……Agency Cost under the Restriction of Free Cash FlowAbstractAgency cost theory is an important branch of capital structural theory. Free cash flow has significant impact on agency cost. The combination of research on these two fields would help to build and extend the theoretical system. Based on agency cost theory, the present study firstly categorized the characteristics of free cash flow as well as the statistical methodologies. Furthermore, the existence of investing free cash flow in agency cost was proved by a model. Then free cash flow was introduced into agency cost theory as restriction, the analysis shows that it will change agency cost, in turn, will have an impact on the relationship between agency cost and capital structure, finally, will influence the optimal capital structure point to maintain the equilibrium. Concretely, with the increasing free cash flow, correspondingly, debt proportion will decrease.Keywords:Capital Structure,Free Cash Flow,Agency Cost,Non-Pecuniary Benefit1. IntroductionAgency cost theory, financial contract theory, signaling model and new pecking order theory are the main branches of new capital structure theory. Financial con-tract theory focuses on restricting stockholders’ behavior by contract and solving the conflict between stockholders and creditors. Signaling model and new pecking order theory center on solving the conflict between investors and managers. These two types of conflict are the main conflict in business organizations. Agency cost theory considers how equilibrium is reached in both types of conflict and how capital structure is formed, which is more theory is more comprehensive than the previous two to some degree.……。

本科毕业设计(论文)外文翻译基本规范

本科毕业设计（论文）外文翻译基本规范
本科毕业设计（论文）外文翻译基本规范：
一、要求
1、与毕业论文分开单独成文。

2、两篇文献。

二、基本格式
1、文献应以英、美等国家公开发表的文献为主（Journals from English speaking countries）。

2、毕业论文翻译是相对独立的，其中应该包括题目、作者（可以不翻译）、译文的出处（杂志的名称）（5号宋体、写在文稿左上角）、关键词、摘要、前言、正文、总结等几个部分。

3、文献翻译的字体、字号、序号等应与毕业论文格式要求完全一致。

4、文中所有的图表、致谢及参考文献均可以略去，但在文献翻译的末页标注：图表、致谢及参考文献已略去(见原文)。

（空一行，字体同正文）
5、原文中出现的专用名词及人名、地名、参考文献可不翻译，并同原文一样在正文中标明出处。

三、毕业论文（设计）外文翻译的内容要求
外文翻译内容必须与所选课题相关，外文原文不少于6000个印刷符号。

译文末尾要用外文注明外文原文出处。

原文出处：期刊类文献书写方法：[序号]作者（不超过3人，多者用等或et al 表示）.题（篇）名[J].刊名（版本）,出版年，卷次（期次）：起止页次。

原文出处：图书类文献书写方法：[序号]作者.书名[M].版本.出版地：出版者,出版年.起止页次。

原文出处：论文集类文献书写方法：[序号]作者.篇名[A].编著者.论文集名[C]. 出版地：出版者，出版年.起止页次。

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利用人工神经网络预测掘进机的性能 Armin Salsani • Jahanbakhsh Daneshian •Shahram Shariati • Abdolreza Yazdani-Chamzini •Mehdi Taheri 收稿日期：2012年12月20日/接收日期：2013年4月19日 ©施普林格出版社伦敦2013 摘要

随着掘进机在全世界越来越多地被使用，以及其在成功完成隧道工程中的显著作用，精确地预测掘进机在不同的地面条件下的性能变得十分必要。另一方面，一些存在于预测模型上的缺点已经使得有必要在新模型的发展上做更多的研究。本文尝试模拟掘进机基于不同岩土和地质的场地条件下的运行速率。为达此目的，人工神经网络（ANN）作为一种进行建模并辨识涉及数据的复杂结构的强大工具，用来模型掘进机的性能和具有很高相关性的影响掘进作业的参数之间的关系。在建模中使用的数据库的编译来自实验室研究，此研究在阿扎德大学和德黑兰、伊朗的科学与研究部进行。研究发现采用4-10-1架构并经过反向传播算法训练的模型最佳。多变量回归（MVR）分析也适用于比较神经网络的性能。结果表明神经网络模型的预测能力比MVR模型更好。得出的结论是掘进机的性能可以被准确的预测为一个无侧限抗压强度的函数，巴西抗拉强度，岩石质量指标，和角987.02R。敏感性分析表明，关于掘进机性能的最有效参数是无侧限抗压强度。

关键词掘进机的性能人工神经网络多变量回归隧道 A. Salsani J. Daneshian 地质系，理学院,Kharazmi大学, 德兰黑，伊朗 e-mail: rmn.salsany@gmail.com J. Daneshian e-mail: jdaneshian@yahoo.com S. Shariati 地质学系，理学院，萨里大学，德兰黑，伊朗

e-mail: shariati.shahram@gmail.com A. Yazdani-Chamzini (&) 采矿工程，工程学院，塔比阿特莫达勒斯大学，德兰黑，伊朗 e-mail: abdalrezaych@gmail.com M. Taheri 采矿工程系，工学部,南德兰黑大学,德兰黑，伊朗

e-mail: taheri.m1362@yahoo.com

在线出版：2013年6月1日 1 引言

掘进机是一种高度灵活和多用途的机器，用于隧道的地下采矿应用和民间隧道，并且和其他机械化开挖方法相比有一个特殊的地方。基于其截割几乎所有隧道断面的能力，掘进机完全得到了民间建筑承包商的认可，他们正在寻找方法来提高生产率并降低成本。尽管掘进机机的首次应用是在20世纪60年代，但是这种机器获得全世界认可是在20世纪70年代末。掘进机对于开挖中低硬度的稳定岩石是更可取的。根据针对开挖的切割原理，掘进机可分为三组：（1）松土或横向类型：杆和磁盘；（2）铣削或纵向（螺旋）的类型；（3）钎类型。为了证明掘进机在规划和调度方面的应用，准确预测瞬时切削率（ICR）是不可避免的。瞬时切削率是作为支持机器性能预测率的目标参数。为了寻找一种掘进机性能和影响其前进速度[4-13]的各种因素之间的逻辑关系近些年已经开发了各种各样的实验模型。在许多情况下，上述的经验模型是不能够识别设计数据集的复杂结构的。另一方面，大多数研究只采用一个变量作为自变量以便所构建的模型是单变量的，并忽略影响掘进过程的其他因素。这些理由驱动人们更好的寻找岩石和掘进机之间的相互作用关系，为了预测掘进机的性能提出一个更精确和确定的模型。为了此目的，利用新开发的方法是有用的，例如人工智能（AI），它可以成功模拟涉及数据的线性和非线性行为。人工神经网络（ANN）作为人工智能的主要分支，在工程科学尤其是采矿和岩石力学[14-23]领域的预测方面的运用是有效的。在本文中，通过引用一个由伊朗的地下采煤项目编制的实验数据集，建立了一个新的基于人工神经网络的模型来预测掘进机性能中的速度。此外，为了评估人工神经网络模型的性能，把通过已建立模型得出的结果与多变量回归（MVR）分析进行比较。本文的其余部分安排如下。这这部分说明了案例研究。2，在这部分中描述了在建模应用的数据集。3，在这部分中讨论了人工神经网络（ANN）的基本概念。4，在这部分。5，提出来多变量回归（MVR）的模型。基于在这部分中提出的概念。2，对预测掘进机性能速率的模型解释。6，为了探讨所建立模型的性能，通过与MVR模型进行比较来仔细检查人工神经网络模型的结果。7，在这部分。8，说了灵敏度分析。最后，在最后一节得出结论。

2 案例研究

塔巴斯煤矿（TCM），塔巴斯煤区的主要部分，位于塔巴斯镇以南约85公里处附近，如在图1中描绘的在伊朗中东部的亚兹德省。本矿区占地面积1200平方公里，估计煤炭储量具有11亿吨[30]。可开采储备量6百万吨焦煤[31]。在这个矿井中，煤层C1采用房柱式方法，应用装载拖运倾卸作业（LHD）和连续采煤机。同样的，掘进机用来建立进入隧道。该C1 煤层坡度是1：5（11），煤层厚度约为 2米[32]。直接顶板由0.1~0.2m厚的粉砂岩/砂岩和泥岩界面组成。直接底板是约1-1.3m厚交替分布的粉砂岩和泥岩煤层。如图1所示，煤层包括主面板，位于主面板两侧的西部和东部面板和两个接入漂移上。图1 塔巴斯煤矿位置和C1煤层[ 32 ] 3 数据集

共61个数据记录在塔巴斯煤炭项目的不同部分被用于建立神经网络模型。此数据库由位于德黑兰阿扎德大学科学研究科编译[33]。无侧限抗压强度（UCS），巴西抗拉强度（BTS），岩石质量指标（RQD），和α角的影响（隧道轴线和弱化的平面之间的夹角）作为输入参数，而ICR作为输出参数。表1给出了基于数据集的描述性统计。

表1 基于数据集的描述性统计无侧限抗压强度(Mpa) 巴西抗拉强度岩石质量指标 角 (度) 瞬时切削率平均值 19.49672 4.078689 19.72131 47.04918 28.55082 中位数 16.40000 4.000000 19.00000 47.00000 25.70000 最大值 28.20000 5.300000 28.00000 54.00000 46.20000 最小值 14.10000 3.600000 18.00000 39.00000 14.60000 标准偏差 5.443680 0.306113 1.826939 4.835377 10.19499 偏度 0.647648 1.124295 2.915079 -0.173 0.247247 峰度 1.628490 5.336853 12.27521 1.554872 1.496767 Jarque–Bera检验 9.045371 26.73081 305.0514 5.612348 6.364926

总和 1189.300 248.8000 1203.000 2870.000 1741.600

4 人工神经网络人工神经网络（ANN）是在建模中使用的一种最流行的机器学习技术。该方法在适用于信息处理系统，神经网络中有许多相互连接的基本单元，称为神经元，参与信息的处理。这些神经元是位于网络层。多层感知器（MLP）是用于建模的神经网络的一般类型，其包括至少三层：输入层，中间层或隐含层和输出层。隐含层和神经元的数目取决于所要解决问题的复杂性[24]。连接环节用于处理神经元之间进行传输的信息。每一个环节的工作是将输入乘以其权重（ijw）。然后，激活函数对输入信号与权重的乘积和进行转移（参照图2）。在简单的情况下，这些单元被简单的相加，通过传递函数产生输出[25]。

一

个人工神经网络的体系结构描述了神经元之间的连接模式，而且对网络的性能有很大的影响。该结构表明了分配连接权值和激活函数的类型的方法，连接权值在网络训练过程中选择，激活函数的类型依赖于建模的目的 [26]。要建立人工神经网络模型，应该用包含足够数量的输入输出数据的训练数据集进行网络训练。训练过程中直到从建模得出的误差能满足总体目标，则训练完成，最佳模型被确定。网络训练之后，构建的网络模型应该用测试数据集进行测试。基于人工神经网络的训练提出了许多算法，其中误差反向传播算法在MLP网络结构中是最流行的学习方法。此算法采用有监督学习过程来构建基于输入输出数据集的网络模式。该算法是周而复始进行的过程，此过程中计算期望值和输出值之间的差，然后对内部神经元的连接权重进行调整[24]。在这个过程中，从已建立的网络输出的结果和实际输出进行比较，计算误差（正向传播）。然后，误差反向传播（反向传播）更新权重和误差 [27]。这个过程反复进行，直到误差收敛为通过成本函数定义的最小阈值，例如均方根误差（RMSE）[28，29]。 5 多变量回归（MVR）为了找到外源变量和内生变量之间的数学模型，采用多变量回归（MVR）的分析。在掘进和采矿领域已经有不同的研究采用这种方法发现独立变量和因变量之间的显著关系[34，35]。在回归分析的过程中，回归函数相关参数的变化可以通过T和F检验的概率分布来分析。 t检验是统计假设检验，如果虚假设成立，则检验统计量遵循Student’s t分布[36]。作为一个重组，连接数据变化的两种方法之间实际差异的计算由t检验进行。 Student’s t检验处理的问题与基于“最小”样本的推理相关[19]：计算出的平均值和标准偏差有可能偏离“真正的”均值和标准偏差。而F检验是统计检验，其中检测统计量是虚假设下的F分布 [36]。此检测适用于调查两组数据的标准偏差是否相等。两方差之比通常用来评估一些项目的显著性。在回归分析的系统中的一个典型的例子是，由偏差做均方回归的均方之比用于检验回归模型的整体显著性 [37]。根据从参照表提取的F值，可以对F值的显著性水平进行分析。通过使用16版本的统计软件包SPSS，并采用来自矿井的实验数据，可以提取一个数学公式（式1），基于如下给出的输入参数对掘进机性能进行建模。

ix

输入 jy

输出加法器激活函

处理单图2 基本人工神经单元