毕业设计模板(正文)外文翻译正文
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金融体制、融资约束与投资——来自OECD的实证分析R.SemenovDepartment of Economics,University of Nijmegen,Nijmegen(荷兰内梅亨大学,经济学院)这篇论文考查了OECD的11个国家中现金流量对企业投资的影响.我们发现不同国家之间投资对企业内部可获取资金的敏感性具有显著差异,并且银企之间具有明显的紧密关系的国家的敏感性比银企之间具有公平关系的国家的低.同时,我们发现融资约束与整体金融发展指标不存在关系.我们的结论与资本市场信息和激励问题对企业投资具有重要作用这种观点一致,并且紧密的银企关系会减少这些问题从而增加企业获取外部融资的渠道。
一、引言各个国家的企业在显著不同的金融体制下运行。
金融发展水平的差别(例如,相对GDP的信用额度和相对GDP的相应股票市场的资本化程度),在所有者和管理者关系、企业和债权人的模式中,企业控制的市场活动水平可以很好地被记录.在完美资本市场,对于具有正的净现值投资机会的企业将一直获得资金。
然而,经济理论表明市场摩擦,诸如信息不对称和激励问题会使获得外部资本更加昂贵,并且具有盈利投资机会的企业不一定能够获取所需资本.这表明融资要素,例如内部产生资金数量、新债务和权益的可得性,共同决定了企业的投资决策.现今已经有大量考查外部资金可得性对投资决策的影响的实证资料(可参考,例如Fazzari(1998)、 Hoshi(1991)、 Chapman(1996)、Samuel(1998)).大多数研究结果表明金融变量例如现金流量有助于解释企业的投资水平。
这项研究结果解释表明企业投资受限于外部资金的可得性。
很多模型强调运行正常的金融中介和金融市场有助于改善信息不对称和交易成本,减缓不对称问题,从而促使储蓄资金投着长期和高回报的项目,并且提高资源的有效配置(参看Levine(1997)的评论文章)。
因而我们预期用于更加发达的金融体制的国家的企业将更容易获得外部融资.几位学者已经指出建立企业和金融中介机构可进一步缓解金融市场摩擦。
编号:毕业设计(论文)外文翻译(原文)院(系):桂林电子科技大学职业技术学院专业:工商企业管理学生姓名:方智立学号:010*********指导教师单位:桂林电子科技大学职业技术学院姓名:朱芸芸职称:讲师2016年 4 月 1 日Marketing Strategy Analysis of SportsAbstractSports market is a special industry market, which for provide exchange of sports tangible products and services market. Sports market including fixed type, such as sports facilities, sports goods market, Mobile market, such as all kinds of sports service provided by the fitness club. Sports tourism and advertising business, sports goods should be consumers to accept, and occupy a larger market. If success of the sports marketing involves many factors. According to the specific characteristics of sports marketing, develop and implement appropriate marketing strategy is very important. Sports marketing strategy is to the sports business units within a certain period or stage marketing campaign's overall development plan of decision making.This paper argues that the marketing strategy can be further subdivided into market positioning strategy, market timing strategy, market entry strategy, market development strategy, market competition strategy, Choose a strategy, must conform to the enterprise's own competitive position, product status, to grasp the market opportunity, determined according to the demands of consumers. In this paper, the sports market segmentation marketing strategy for the market positioning strategy, market timing strategy, market entry strategy, market development strategy, market competition strategy, and discusses the sports marketing how to carry out strategic choice.Keywords: Sports bazaar ; Sports marketing; Marketing strategy1.Sports marketing strategy and characteristics1.1Sports marketing strategyStrategy refers to the planning of overall and profound things. Sports marketing strategy refers to the commodity business units under the guidance of modern marketing concept, to achieve its economic goal for enterprise in a certain period of the overall design and planning of marketing development.Inan increasingly competitive market circumstances, sports business units in order to effectively carry out business activities, to achieve its business objectives, must understand and based on the characteristics of marketing concepts and strategies, and Target the demand of the market, comprehensive analysis and marketing of various environmental factors, choose effective market strategy in the background.1.2The characteristics of the sports marketing strategySports marketing strategy has sports business units within a certain period or stage marketing campaign's overall development plan of decision making. It has the characteristics of the following.(1) Overall importance.Sports marketing strategy is a matter of the global business units, including two aspects the meaning of this global:on the one hand, Sports marketing strategy is the overall design, the development of the business units, including overall planning and the overall strategy and means.On the other hand, Sports marketing strategy decision is a matter of global business units and their all-round development in the future.(2)Secular.Sports marketing strategy is really about the future of sports business units: to achieve the goals of sports marketing strategy, will make the sports business units to produce qualitative leap, but this is not usually that can be done in the short term.Important, sports business units of marketing strategy on the strategic period not only very important to enterprise's survival and development, but also to the long-term development of enterprises play an important role.(3) Systematicness.Sports systemic marketing refers to business units, each part of the work of each link is a contact each other, are closely related to the organic unity of the whole.System have layers, the size and the primary and secondary division, at the next lower level to obey and serve at the next higher level.For a certain sports and business operation entity, the strategy of the whole enterprise as a whole system engineering to overall arrangement, the pursuit of the overall development of the biggest benefits.(4)Adaptability.Sports marketing adaptability, refers to the sports marketing and business operation entity is easily affected by external and internal environment, when the environment changes, sports business units made to adapt themselves to the new environment of the characteristics of rapid response.Sports marketing of the external environment including the market demand, political or economic situation changes, policy and law changes. Similarly, sports business entities internal conditions change will impact on marketing.(5)Risk.Due to sports marketing strategy is the business unit for the marketing activities during the period development collection of expected decision, and this decision is absolutely impossible in various conditions fully mature and information fully, make and sports market, especially the intangible product variety and complexity of the market, make sports marketing strategy has the characteristics of uncertainty and instantaneity, many market opportunities tend to be a passes, no longer to, opportunity and risk coexist.2.Sports marketing strategy comprisedand choiceSports marketing strategies mainly include market positioning strategy, market timing strategy, market entry strategy, market development strategy, market competition strategy.2.1 Market orientation strategyMarket positioning refers to the sports business units according to the condition of market competition situation and its own resources, establish and develop differentiated competitive advantage, to make their own products in the consumer formed in the difference between each product unique image and is superior to the competition.This unique image can be tangible or intangible.Enterprise after analyzing the market environment, should highlight its own market advantage, establish market position, Which companies need to know on a certain level of paper generalizes, consumers mind what is the best sports products as expected.2.2 Market entry policyMarket entry strategy is the sports business units at the right time to capture the target market, how to appropriately in the two aspects of production capacity and sales ability to make reliable measures and guarantee, to ensure the decision-making of sports products successfully enter the market.Its content mainly includes the production capacity of decision-making and sales ability to form two aspects.(1) Capacity Decision. In the necessary time, sports business entities formtargetmarket capacity, is one of the important conditions to achieve market goal.Regardless of whether they are sports tangible products and intangible products, generally there are two alternative strategies.①Independent development strategy refers to both tangible products, the development of sports and development of sports intangible products. All on its own strength to expand production scale, enhance the comprehensive production capacity or adjust the structure of the comprehensive production capacity of enterprise, to adapt the demand of product combination structure. ②Comprehensive development strategy, mainly depend on the sports business units of the external forces, namely, through joint, collaboration, subcontract, form a new comprehensive production capacity. Due to participating in planning, control, coordination, etc, are more difficult. Therefore, sports business units must be good at optimizing collaborator, deal with the various cooperation of responsibility, right and benefit, to maintain good relations of cooperation.(2) Sales ability decision. A sports product to enter and occupy the market, production enterprise must have the necessary sales ability and the ability to penetrate the market.Sales ability decision-making main consideration circulation channels and sales, product should be considered when making decisions, market, enterprise, social environment and the factors such as economic effect.2.3 Market development strategyMarket development strategy refers to the perspective of market prospects, the choice of market development means, usually includes two kinds of intensive development and diversified development main form.(1)Intensive development.When some kind of sports products in the market has the potential of further development, the choice of market penetration, product development and market development of three kinds of intensive development form. As the tangible products market, in sports and intangible products are common market and applicable.①Market penetration. on the basis of the existing market scale, increase the sales of existing products. Can use a variety of measures, consolidate old customers, increase the new user. ②Product development Is through developing and improving existing products, make its have some new properties and USES, meet the social demand more. ③market development. Refers to an enterprise that open up new product sales market, in order to increase sales.(2) Diversified development.Diversity is also called the diversification, basically have concentricity scattered scattered, horizontal dispersion and the integrityof three. ①Concentricity is sports business unit USES the original dispersed development technology and the characteristics, with its as the core, the development use different structure similar products. ②Scattered level of sexual development.Was used in the original market advantage, has occupied the market development of technology, nature and purpose of different products. For example, Sports club olicy makers, can through the player transfer channels, to sell players, profit.Others use their sports club or the player's social awareness to participate in the sales promotion of goods, in order to obtain profits. ③Integrity of dispersed development. Refers to the sports business units to expand the business into its original business, technology, market and the product has no connection in the industry. Such as the sports department construction and run a catering and service hotels, hotels, entertainment city, charge for parking lot, etc., is the form of scattered holistic development. Implement the diversification development, can improve the ability of sports business units to adapt to the environment, reduce the risk of a single business, at the same time, may be more fully use of all kinds of resources within the enterprise, make its have more potential development opportunities. However, the development of decentralized often leads to complication of operation and management, and business operation entities such as diversifying some problems.2.4Strategic Marketing CompetitionThe rules of the development of the market is superior bad discard, its characteristic is the petition can promote the economic development of the enterprise and the improvement of economic benefits.Enterprises should establish a clear concept of competition, flexible use of price and non-price competition means, take a man without I have, people have my good, good people knew, new I cheap, cheap I turn the principle and method of making enterprise competitive strategy, must accomplish know fairly well the competition environment and competition situation, can with ease.Enterprise competition environment factors mainly refers to the enterprise in addition to the social and cultural environment stress factors of various aspects, such as management scientist professor Michael porter of Harvard University famous the competitive offer slightly above, an enterprise usually exist competition pressure from five aspects, namely the industry competition pressure, potential to join the pressure from the industry, suppliers forward pressure (by providing raw materials or semi-finished products, to develop into their production products), buyers.(1) The overall competitive strategy. Under different conditions, the enterprise facing the pressure of competition is different, the analysis of the pressure of competition is to understand the purpose of each kind of competition situation of power, so as to make effective competition strategy.Under normal circumstances, the sports business units of competition strategy in general have a low cost strategy, product differentiation strategy and intensive strategy. ①low-cost strategy. Low cost strategy is to point to in under the premise of guarantee the quality of products and services, efforts to reduce the cost of production and sales so that the enterprise product prices lower than competitors' prices, with rapidly expanding sales increase market share. ②Product differentiation strategies. Product differentiation strategy is to point to create a unique characteristic of the enterprise products, to develop unique products or marketing programs, for in such aspects as product or service than competitors are unique. Thus to obtain the difference advantage.The United States, for example, "NIKE" brand sports shoes, NIKE production due to the appearance of novel design, the innovation of the use function and unique, and exquisite packaging, etc., although the price is surprisingly expensive, but occupies considerable market in China, the teenagers are very loving. ③Intensive strategy. Intensive strategy refers to the enterprises focus on one or several market segments provide the most effective service, better meet certain customers with different needs, so as to strive for the local competitive advantage. It is little different from the above three kinds of overall competition strategy, successfully implement these three strategies need different resources and decision-making, also should have different requirements on organization and management.(2) The competitive strategy of enterprises of different competitive position. Where the status of enterprise in market competition, the enterprise can be divided into: market leader, market challenger, market follower. Different competitive position of enterprises, should choose different market competitive strategy.①Dominant market competition strategy. Market power refers to the related products has the highest market share. Such as the current market position and stable dominated by clothing JinMeiLong, "ADIDAS", they are price changes, new product development, sales channel width and promotional efforts in a dominant position, recognized by other sports enterprises. ②The challenger market competition strategy. Market challenger refers to those in a secondary position in the market of the enterprise, such as "lining" brand garment enterprises .Market challenger to choosechallenge object is closely related to the strategic target, for a same object has different goals and strategies Such as attack market leader to gain the market share and product advantage ;Attack power with yourself quite seize its market position; Attacking small businesses taking their customers even small business itself."Lining" to win market price advantage to the international brand, with product quality advantages to gain "anta" challenger "peak" brand's market share. ③Followers of the market competition strategy. Market followers is to point to in a secondary position, under the conditions of "coexistence" market for as much as possible the benefit of the enterprise. Market followers don't need a lot of money, less risky and can obtain high profits, so many enterprises adopt this strategy, especially the sort of small or no fame and status of sports clothing enterprises. As the current sports "philharmonic" brand clothing enterprise in the enterprise.Reference[1] LiJianJun,WangCuiHua:The Research on Marketing Environment Enterprise of Things for Sports Use in China[J] Journal of NanJing institute of sport (social science edition) 2013.(10),36 ~ 48.[2] Discuss Sports market, products and marketing characteristics. [J] journal of xi ' an institute of physical education,2012.(3)101 ~109.[3] HuZhengMing Ed. Marketing Management[M].Shandong people's publishing house,2012.302 ~325.[4] [US]Kotler write. YuLiJun translate. Introduction to Marketing[M].Huaxia Publishing House,2011.333~389.[5] ZhangTongYao.Application areas to promote the marketing advantage analysis of third party logistics[J].Market of China,2010(3)128 ~136.[6] WangHuaiShu.The influence of the logistics quality of marketing[J].Teacher's Journal,2010(3)31 ~38.[7] WangChenWen.Shallow theory of logistics strategy in the role of marketing management[J].Chemical Enterprise Management,2009(7)175 ~178.。
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。
©2004 美国光学学会光学分类与标引体系编码:(140.7010)捕获、(170.4520)光学限制与操作和(230.6120)空间光调制器。
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]。
毕业设计英文作文范文Title: The Importance of the Graduation Project in Academic Development。
The graduation project holds a pivotal role in the academic journey of students. It serves as a culmination of years of learning, a platform to showcase acquired skills, and an opportunity to delve deep into a specific subject matter. In this essay, I will elaborate on the significance of the graduation project and its impact on academic development.Firstly, the graduation project fosters independent learning and critical thinking skills. Unlike regular coursework where the parameters are often well-defined, the graduation project requires students to identify a research question or a problem statement independently. This process necessitates thorough literature review, data collection, and analysis, thereby honing research and analytical abilities. Moreover, formulating hypotheses, designingexperiments, or proposing solutions demand creativethinking and problem-solving skills, which are essentialfor academic and professional success.Secondly, the graduation project encourages interdisciplinary learning and collaboration. Many projects involve aspects from various fields, prompting students to integrate knowledge acquired from different courses. This interdisciplinary approach not only enriches the project but also broadens students' perspectives, enabling them to appreciate the interconnectedness of different subjects. Furthermore, collaboration with peers, mentors, or industry professionals enhances teamwork, communication, and project management skills, which are indispensable in any academic or professional setting.Additionally, the graduation project cultivates resilience and perseverance. Research, by its nature, is fraught with challenges, setbacks, and uncertainties. Students encounter obstacles ranging from experimental failures to data inconsistencies, requiring them to adapt, troubleshoot, and persist in the face of adversity.Overcoming these hurdles instills resilience and fortitude, attributes that are invaluable not only in academia but also in life.Moreover, the graduation project offers a platform for personal and intellectual growth. It provides students with the autonomy to explore topics of their interest, delveinto uncharted territories, and push the boundaries of knowledge. This journey of self-discovery not only enhances academic curiosity but also fosters a sense of ownership and accomplishment. Furthermore, presenting findings, defending arguments, and receiving feedback during project evaluations contribute to the development of presentation, communication, and critical evaluation skills, which are essential for academic and professional success.In conclusion, the graduation project is a cornerstone of academic development, offering students a unique opportunity to apply theoretical knowledge to real-world problems, fostering independent learning, interdisciplinary collaboration, resilience, and personal growth. By engaging in this endeavor, students not only demonstrate theiracademic prowess but also equip themselves with essential skills and attributes for future endeavors. Therefore, the graduation project stands as a testament to the culmination of academic journey and the beginning of a new chapter in students' intellectual and professional pursuits.。
毕业小作文排版模板## 英文回答:Introduction。
Graduation is a significant milestone in one's academic journey. It marks the culmination of years of hard work, dedication, and perseverance. As I stand at this transformative moment, I am overwhelmed with emotions of gratitude, accomplishment, and anticipation.Reflecting on my university experience, I am grateful for the invaluable knowledge and skills I have acquired. Through rigorous coursework, thought-provoking discussions, and hands-on research, I have developed a deep understanding of my chosen field. This intellectual foundation will serve as a cornerstone for my future endeavors.Beyond the classroom, university life has provided mewith a wealth of personal and social experiences. I have forged lifelong friendships, worked collaboratively on projects, and actively engaged in extracurricular activities. These experiences have fostered my critical thinking, communication, and leadership skills, preparing me for the challenges and opportunities that lie ahead.Challenges and Growth。
华南理工大学广州学院本科生毕业设计(论文)翻译英文原文名Review of Vibration Analysis Methods for Gearbox Diagnostics and Prognostics中文译名对变速箱振动分析的诊断和预测方法综述学院汽车工程学院专业班级车辆工程七班学生姓名刘嘉先学生学号201130085184指导教师李利平填写日期2015年3月15日英文原文版出处:Proceedings of the 54th Meeting of the Society for Machinery Failure Prevention Technology, Virginia Beach,V A, May 1-4,2000,p. 623-634译文成绩:指导教师(导师组长)签名:译文:简介特征提取技术在文献中有描述;然而,大多数人似乎掩盖所需的特定的预处理功能。
一些文件没有提供足够的细节重现他们的结果,并没有一个全面的比较传统的功能过渡齿轮箱数据。
常用术语,如“残差信号”,是指在不同的文件不同的技术.试图定义了状态维修社区中的常用术语和建立所需的特定的预处理加工特性。
本文的重点是对所使用的齿轮故障检测功能。
功能分为五个不同的组基于预处理的需要。
论文的第一部分将提供预处理流程的概述和其中每个特性计算的处理方案。
在下一节中,为特征提取技术描述,将更详细地讨论每一个功能。
最后一节将简要概述的宾夕法尼亚州立大学陆军研究实验室的CBM工具箱用于齿轮故障诊断。
特征提取概述许多类型的缺陷或损伤会增加机械振动水平。
这些振动水平,然后由加速度转换为电信号进行数据测量。
原则上,关于受监视的计算机的健康的信息被包含在这个振动签名。
因此,新的或当前振动签名可以与以前的签名进行比较,以确定该元件是否正常行为或显示故障的迹象。
在实践中,这种比较是不能奏效的。
由于大的变型中,签名的直接比较是困难的。
相反,一个涉及从所述振动署名数据特征提取更多有用的技术也可以使用。
CLUTCHThe engine produces the power to drive the vehicle. The drive line or drive train transfers the power of the engine to the wheels. The drive train consists of the parts from the back of the flywh eel to the wheels. These parts include the clutch, th e transmission, the drive shaft, and the final drive assembly (Figure 8-1).The clutch which includes the flywheel, clutch disc, pressure plate, springs, pressure plate cover and the linkage necessary to operate the clutch is a rotating mechanism between t he engine and the transmission (Figure 8-2). It operates through friction which comes from contact between the parts. That is the reason why the clutch is called a friction mechanism. After engagement, the clutch must continue to transmit all the engine torque to the transmission depending on the friction without slippage. The clutch is also used to disengage the engine from the drive train whenever the gears in the transmission are being shifted from one gear ratio to another.To start the engine or shift the gears, the driver has to depress the clutch pedal with the purpose of disengagement the transmission from the engine. At that time, the driven members connected to the transmission input shaft are either stationary or rotating at a speed that is slower or faster than the driving members connected to the engine crankshaft. There is no spring pressure on the clutch assembly parts. So there is no friction between the driving members and driven members. As the driver lets loose the clutch pedal, spring pre ssure increases on the clutch parts. Friction between the parts also increases. The pressure exerted by the springs on the driven members is controlled by the driver through the clutch pedal and linkage. The positive engagement of the driving and driven members is made possible by the friction between the surfaces of the members. When full spring pressure is applied, the speed of the driving and driven members should be the same. At themoment, the clutch must act as a solid coupling device and transmit al l engine power to the transmission, without slipping.However, the transmission should be engaged to the engine gradually in order to operate the car smoothly and minimize torsional shock on the drive train because an engine at idle just develops little power. Otherwise, the driving members are connected with the driven members too quickly and the engine would be stalled.The flywheel is a major part of the clutch. The flywheel mounts to the engine’s crankshaft and transmits engine torque to the clutch assembly. The flywheel, when coupled with the clutch disc and pressure plate makes and breaks the flow of power from the engine to the transmission.The flywheel provides a mounting location for the clutch assembly as well. When the clutch is applied, the flyw heel transfers engine torque to the clutch disc. Because of its weight, the flywheel helps to smooth engine operation. The flywheel also has a large ring gear at its outer edge, which engages with a pinion gear on the starter motor during engine cranking.The clutch disc fits between the flywheel and the pressure plate. The clutch disc has a splined hub that fits over splines on the transmission input shaft. A splined hub has grooves that match splines on the shaft. These splines fit in the grooves. Thus, t he two parts are held together. However, back-and-forth movement of the disc on the shaft is possible. Attached to the input shaft, At disc turns at the speed of the shaft.The clutch pressure plate is generally made of cast iron. It is round and about the same diameter as the clutch disc. One side of the pressure plate is machined smooth. This side will press the clutch disc facing are against the flywheel. The outer side has various shapes to facilitate attachment of spring and release mechanisms. The two primary types of pressure plate assemblies are coil spri ng assembly and diaphragmspring (Figure 8-3).In a coil spring clutch the pressure plate is backed by a number of coil springs and housed with them in a pressed-steel cover bolted to the flywheel. The springs push against the cover. Neither the driven plate nor the pressure plate is connected rigidly to the flywh eel and both can move either towards it or away. When the clutch pedal is depressed a thrust pad riding on a carbon or ball thrust bearing i s forced towards the flywheel. Levers pivoted so that they engage with the thrust pad at one end and the pressure plate at the other end pull the pressure plate ba ck against its springs. This releases pressure on the driven plate disconnecting the gearbox from the engine (Figure 8-4).Diaphragm spring pressure plate assemblies are widely used in most modern cars. The diaphragm spring is a single thin sheet of metal which yields when pressure is applied to it. When pressure is removed the metal springs back to its original shape. The centre portion of the diaphragm spring is slit into numerous fingers that act as release levers. When the clutch assembly rotates with the engine these weights are flung outwards by centrifugal forces and cause the levers to pre ss against the pressure plate. During disengagement of the clutch the fingers are moved forward by the release bearing. The spring pivots over the fulcrum ring and its outer rim moves away from the flywheel. The retracting spring pulls the pressure plate a way from the clutch plate thus disengaging the clutch (Figure 8-5).When engaged the release bearing and the fingers of the diaphragm spring move towards the transmission. As the diaphragm pivots over the pivot ring its outer rim forces the pressure plate against the clutch disc so that the clutch plate is engaged to the flywheel.The advantages of a diaphragm type pres sure plate assembly are its compactness, lower weight, fewer moving parts, less effort to engage, reduces rotational imbalance by providin g a balanced force around the pressure plate and less chances of clutch slippage.The clutch pedal is connected to the disengagement mechanism either by a cable or, more com monly, by a hydraulic system. Either way, pushing the pedal down operates the dise ngagement mechanism which puts pressure on the fingers of the clutch diaphragm via a release bearing and causes the diaphragm to release the clutch plate. With a hydraulic mechanism, the clutch pedal arm operates a piston in the clutch master cylinder. Thi s forces hydraulic fluid through a pipe to the clutch release cylinder where another piston operates the clutch disengagement mechanism. The alternative is to link the clutch pedal to the disengagement mechanism by a cable.The other parts including the cl utch fork, release bearing, bell-housing, bell housing cover, and pilot bushing are needed to couple and uncouple the transmission. The clutch fork, which connects to the linkage, actually operates the clutch. The release bearing fits between the clutch fork and the pressure plate assembly. The bell housing covers the clutch assembly. The bell housing c over fastens to the bottom of the bell housing. This removable cover allows a mechanic to inspect the clutch without removing the transmission and bell housing. A pilot bushing fits into the back of th e crankshaft and holds the transmission input shaft.A Torque ConverterThere are four components inside the very strong housing of the torque converter:1. Pump;2. Turbine;3. Stator;4. Transmission fluid.The housing of the torque converter is bolted to the flywheel of the engine, so it turns at what ever speed the engine is running at. The fins that make up the pump of the torque converter are at tached to the housing, so they also turn at the same speed a s the engine. The cutaway below shows how everything is connected inside the torque converter (Figure 8-6).The pump inside a torque converter is a type of centrifugal pump. As it spins, fluid is flung to the outside, much as the spin cycle of a washing machine flings water and clothes to the outside of the wash tub. As fluid is flung to the outside, a vacuum is created that draws more fluid in at the center.The fluid then enters the blades of the turbine, which is connected to the transmission. The turbin e causes the transmission to spin, which basically moves the car. The blades of the turbine are curved. This means that the fluid, which enters the turbine from the outside, has to change direction before it exits the center of the turbine. It is this directional change that causes the turbine to spin.The fluid exits the turbine at the center, moving in a different direction than when it entered. The fluid exits the turbine moving opposite the direction that the pump (and engine) is turning. If the fluid were allowed to hit the pump, it would slow the engine down, wasting power. This is why a torque converter has a stator.The stator resides in the very center of the torque converter. Its job is to redirect the fluid returning from the turbine before it hits the pump again. This dramatically increases the efficiency of the torque converter.The stator has a very aggressive blade design that almost completely reverses the direction of the fluid. A one-way clutch (inside the stator) connects the stator to a fixed shaft in the transmission. Because of this arrangement, the stator cannot spin with the fluid - i tc a n s p i n o n l y i n t h e o p p o s i t ed i re c t i o n,f o r c i ng th e f l ui d t oc h a n g ed i re c t i o n a s i t h i t s t h e s t a t o r b l a d e s.Something a little bit tricky happens when the car gets moving. There is a point, around 40 mph (64 kph), at which both the pump and the turbine are spinning at almost the same speed (the pump alwaysspins slightly faster). At this point, the fluid returns from the turbine, entering the pump already moving in the same direction as the pump, so the stator is not needed.Even though the turbine changes the direction of the fluid and flings it out the back, the fluid still ends up moving in the direction that the turbine is spinning because the turbin e is spinning faster in one direction than the fluid is being pumped in the other direction. If you were standing in the back of a pickup moving at 60 mph, and you threw a ball out the back of that pickup at 40 mph, the ball would still be going forward at 20 mph. This is similar to what happens in the tur bine: The fluid is being flung out the back in one direction, but not as fast as it was going to start with in the other direction.At these speeds, the fluid actually strikes the back sides of the stator blades, causing the stator to freewheel on its one-way clutch so it doesn’t hinder the fluid moving through it.Benefits and Weak PointsIn addition to the very important job of allowing a car come to a complete stop without stalling the engine; the torqu e converter actually gives the car more torque when you accelerate out of a Stop. Modern torque converters can multiply the torque of the engine by two to three times. This effect only happens when the engine is turning much faster than the transmission.At higher speeds, the transmission catches up to the engine, eventually moving at almost the same speed. Ideally, though, the transmission would move at exactly the same speed as the engine, because this difference in speed wastes power. This is part of th e reason why cars with automatic transmissions get worse gas mileage than cars with manual transmissions.To counter this effect, some cars have a torque converter with alockup clutch. When the two halves of the torque converter get up to speed, this clutch locks them together, eliminating the slip page and improving efficiency.。
毕业设计外文资料翻译学院:信息科学与工程学院专业:软件工程姓名: XXXXX学号: XXXXXXXXX外文出处: Think In Java (用外文写)附件: 1.外文资料翻译译文;2.外文原文。
附件1:外文资料翻译译文网络编程历史上的网络编程都倾向于困难、复杂,而且极易出错。
程序员必须掌握与网络有关的大量细节,有时甚至要对硬件有深刻的认识。
一般地,我们需要理解连网协议中不同的“层”(Layer)。
而且对于每个连网库,一般都包含了数量众多的函数,分别涉及信息块的连接、打包和拆包;这些块的来回运输;以及握手等等。
这是一项令人痛苦的工作。
但是,连网本身的概念并不是很难。
我们想获得位于其他地方某台机器上的信息,并把它们移到这儿;或者相反。
这与读写文件非常相似,只是文件存在于远程机器上,而且远程机器有权决定如何处理我们请求或者发送的数据。
Java最出色的一个地方就是它的“无痛苦连网”概念。
有关连网的基层细节已被尽可能地提取出去,并隐藏在JVM以及Java的本机安装系统里进行控制。
我们使用的编程模型是一个文件的模型;事实上,网络连接(一个“套接字”)已被封装到系统对象里,所以可象对其他数据流那样采用同样的方法调用。
除此以外,在我们处理另一个连网问题——同时控制多个网络连接——的时候,Java内建的多线程机制也是十分方便的。
本章将用一系列易懂的例子解释Java的连网支持。
15.1 机器的标识当然,为了分辨来自别处的一台机器,以及为了保证自己连接的是希望的那台机器,必须有一种机制能独一无二地标识出网络内的每台机器。
早期网络只解决了如何在本地网络环境中为机器提供唯一的名字。
但Java面向的是整个因特网,这要求用一种机制对来自世界各地的机器进行标识。
为达到这个目的,我们采用了IP(互联网地址)的概念。
IP以两种形式存在着:(1) 大家最熟悉的DNS(域名服务)形式。
我自己的域名是。
所以假定我在自己的域内有一台名为Opus的计算机,它的域名就可以是。
南京理工大学紫金学院毕业设计(论文)外文资料翻译系:机械系专业:车辆工程专业姓名:宋磊春学号:070102234外文出处:EDU_E_CAT_VBA_FF_V5R9(用外文写)附件:1。
外文资料翻译译文;2.外文原文.附件1:外文资料翻译译文CATIA V5 的自动化CATIA V5的自动化和脚本:在NT 和Unix上:脚本允许你用宏指令以非常简单的方式计划CATIA。
CATIA 使用在MS –VBScript中(V5.x中在NT和UNIX3。
0 )的共用部分来使得在两个平台上运行相同的宏。
在NT 平台上:自动化允许CATIA像Word/Excel或者Visual Basic程序那样与其他外用分享目标。
ATIA 能使用Word/Excel对象就像Word/Excel能使用CATIA 对象。
在Unix 平台上:CATIA将来的版本将允许从Java分享它的对象。
这将提供在Unix 和NT 之间的一个完美兼容。
CATIA V5 自动化:介绍(仅限NT)自动化允许在几个进程之间的联系:CATIA V5 在NT 上:接口COM:Visual Basic 脚本(对宏来说),Visual Basic 为应用(适合前:Word/Excel ),Visual Basic。
COM(零部件目标模型)是“微软“标准于几个应用程序之间的共享对象。
Automation 是一种“微软“技术,它使用一种解释环境中的COM对象。
ActiveX 组成部分是“微软“标准于几个应用程序之间的共享对象,即使在解释环境里。
OLE(对象的链接与嵌入)意思是资料可以在一个其他应用OLE的资料里连结并且可以被编辑的方法(在适当的位置编辑).在VBScript,VBA和Visual Basic之间的差别:Visual Basic(VB)是全部的版本。
它能产生独立的计划,它也能建立ActiveX 和服务器。
它可以被编辑。
VB中提供了一个补充文件名为“在线丛书“(VB的5。
Reliability of Frame and Shear Wall Structural Systems. I: StaticLoadingAhmed GhobarahAbstract:An efficient and accurate algorithm is developed to evaluate the reliability of a steel frame and reinforced concrete shear wall structural system subjected to static loading. In a companion paper, the algorithm is extended to consider dynamic loading, including seismic loading. The concept integrates the finite-element method and the first-order reliability method, leading to a stochastic finite element-based approach.In the deterministic finite-element representation, the steel frame is represented bybeam-column elements and the shear walls are represented by plate elements. The stiffness matrix for the combined system is then developed. The deterministic finite-element algorithm is verified using a commercially available computer program. The deterministic algorithm is then extended to consider the uncertainty in the random variables. The reliability of a steel frame with and without the presence of reinforced concrete shear walls is evaluated for the strength and serviceability performance functions. The results are verified using Monte Carlo simulations. The algorithm quantitatively confirms the beneficial effect of shear walls, particularly when the steel frame is weak in satisfying the serviceability requirement of lateral deflection. The algorithm can be used to estimate the reliability of any complicated structural system consisting of different structural elements and materials when subjected to static loading. The procedure will be useful in the performance-based design guidelines under development by the profession. keywords:Limit states; Simulation; Shear walls; Static loads; Steel frames; Finite element method.IntroductionThe realistic reliability analysis of complicated structural systems consisting of different types of structural elements and materials is a major challenge to our profession. In most cases, the limit state or performance function (a functional relationship between the load- and resistance-related variables and the performance criterion) is implicit in evaluating the reliability of such systems. The analytical technique most frequently used to capture the mechanical behavior of complicated structural systems consisting of different materials appears to be the finite-element method (FEM)-based approach. Finite-element analysis is a powerful tool commonly used in many engineering disciplines to analyze simple or complicated structural systems. With this approach, it is straightforward to consider complicated geometric arrangements,various sources of nonlinearity, different materials, and the load path to failure. However, the deterministicfinite-element method fails to consider the uncertainty in the variables, and thus cannot be used for reliability analysis. On the other hand, the available reliability methods fail to represent structures as realistically as possible. If the basic variables are uncertain, every quantity computed during the deterministic analysis is also uncertain. The currently available reliability methods can still be used if the uncertainty in the response can be tracked in terms of thevariation of the basic variables at every step of the deterministic analysis. To capture the desirable features of these two approaches, they needed to be combined, leading to the concept of the stochastic finite-element method (SFEM) (Haldar and Mahadevan 2000b)。
The SFEM algorithm for frame structures has been developed by several researchers. However, the main drawback of frame structures is their inability to transfer horizontal loads (e.g., wind, earthquake, and ocean waves) effectively. They are relatively flexible. To increase their lateral stiffness, bracing systems or shear walls are needed. Haldar and Gao (1997) Attempted to consider bracing systems in a steel frame structure. They used truss elements in their model. However, there has not been an attempt to consider shear walls, represented by two dimensional plate elements, in a frame in the context of SFEM.Numerical ExamplesTo investigate the effect of shear walls on the overall reliability, both a frame without shear walls and a frame with shear walls are studied in this study. All loads are applied statically. The reliability of the frame with and without shear walls is evaluated using the proposed algorithm. The accuracy of the proposed algorithm is established using Monte Carlo simulations. Reliability Analysis of Frame without Shear WallsA two-story two-bay frame shown in Fig. 2 (Fig. 1 without the shear walls) is considered first. A36 steel is used. The statistical characteristics of the cross-sectional and material properties required for the reliability analysis are given in Table 3. The frame is subjected to dead, live, and horizontal loads. The statistical properties of these loads are given in Table 3.For the strength limit state, the reliability of the most critical beam at node e and the most critical column at node c are evaluated using the proposed algorithm with the performance functions represented by Eqs. (13) and (14). For the serviceability limit state, the horizontal drift of the top floor at node a and the vertical deflection of the beam at the midspan at node d are checked. In Eq. (20), the prescribed horizontal drift at the top floor is considered to not exceedh/400, where h is the height 006Ff the frame. Thus, is equal to 1.83cm in this example. Similarly, the prescribed vertical deflection in the midspan of the beam is considered to be l/360under the unfactored live load, where l is the span length of the beam. In this case, is considered to be 2.54cm.Considering all the random variables given in Table 3, the corresponding reliability indexes and the probabilities of failure at different node points are evaluated. The results are summarized in Table 4. For the frame without shear walls, the probability of failure of the beam is found to be 0.0039, and 10,000 simulations were used to capture this behavior. For the horizontal drift, the probability of failure is close to zero. Considering the practical aspects of supercomputer utilization, 100,000 simulations were used to capture this behavior: The Monte Carlo simulation results are summarized in Table 4.Reliability Analysis of Frame with Shear WallsThe frame shown in Fig. 2 is reinforced with shear walls as shown in Fig. 1. The statistical properties of two additional variables related to the shear walls, E c and ν, are given in Table 3. The building is assumed to contain five similar frames connected by rigid diaphragms at the floor levels. Only the center frame of the building is assumed to have shear walls. Although the physical thickness of the shear wall is 12.7cm,considering the presence of five similar frames and the rigid behavior of diaphragms, the effective thickness per frame is assumed to be 2.54 cm in this study. The combined system is subjected to the three static loads given in Table 3. After the tensile stress of each shear wall exceeds the prescribed tensile stress of concrete, the degradation of the shear wall stiffness is assumed to be reduced to 40% of the original stiffness.The probability of failure of the combined system is calculated using the proposed algorithm. For the strength limit state, the probability of failure of a column, represented by Node eg in Figs. 1 and 2, is estimated. For the serviceability limit state, the horizontal deflection at the top of the combined system (point a in Figs. 1 and 2) is evaluated. The results are summarized in Table 4.As before, 10,000 simulations are used for the strength limit state and 100,000 simulations are used for the serviceability limit state. For both the strength and serviceability limit states, the reliability indexes estimated by the proposed algorithm and the Monte Carlo simulation technique are similar. The results clearly indicate that the proposed algorithm can be used to estimate the probability of failure of a combined system consisting of frame and shear walls under static loading. The reliability of the column did not change significantly due to the presence of shear walls. However, the horizontal drift at the top of the frame reduced significantly and the probability of failure of the combined system in serviceability became almost zero. This is expected. For the combined system, the controlling limit state has changed from serviceability to strength. This simple example clearly demonstrates the beneficial effect of shear walls in carrying horizontal loads. It also demonstrates that the proposed algorithm can be used to estimate the reliability of a complicated structural system under static loading conditions, broadening the application potential of reliability methods.ConclusionsAn efficient and accurate algorithm is developed to evaluate the reliability of a steel frame and RC shear wall structural system. The steel frame is represented by beam-column elements and the shear walls are represented by plate elements. A stochastic finite element-based approachconsisting of the reliability approach, the first-order reliability analysis procedure, and thefinite-element method is proposed. The reliability of a frame with and without shear walls is evaluated for the strength and serviceability performance functions. The results are verified using the Monte Carlo simulation technique. The proposed stochastic finite-element-based algorithm is reasonable for evaluating the reliability of a combined system consisting of frame and shear walls for static loading. It gives similar results for both the strength and serviceability performance functions compared to the results from Monte Carlo Simulation. As expected, this study showed that the reliability of a frame for horizontal deflection could be significantly improved with the help of shear walls. The proposed algorithm to evaluate the reliability of a combined system consisting of steel frames and RC shear walls for static loading is very unique. It produces accurate and efficient results, and can be used in the future to evaluate the reliability of complicated structural systems. The proposed algorithm demonstrates how reliability methods can be applied to evaluate the risk of a real structural system capturing its realistic mechanical behavior. The procedure will be useful in the performance-based design guidelines under development by the profession.References[1] Chaallal O, Nollet M-J, Perraton D. Shear strengthening of RC beams by externallybonded side CFRP strips. Journal of Composites for Construction, ASCE 1998;2(2):111–3.[2] Spadea G, Bencardino F, Swamy RN. Structural behaviour of composite RC beams withexternally bonded CFRP. Journal of Composites for Construction, ASCE1998;2(3):132–7.[3] Saadatmanesh H, Ehsani MR, Li MW. Strength and ductility of concrete columnsexternally reinforced with fibre composite straps. ACI Structural Journal1994;91(4):434–47.[4] Saadatmanesh H, Ehsani MR, Jin L. Seismic strengthening of circular bridge pier modelswith fibre composites. ACI Structural Journal 1996;93(6):639–47.[5] Saadatmanesh H, Ehsani MR, Jin L. Seismic retrofitting of rectangular bridge columnswith composite straps.Earthquake Spectra 1997;13(2):281–304.。