專業(yè)英語課程論文

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《專業(yè)英語》課程論文（工業(yè)工程 09 級）姓名：學(xué)號：教師：年 11 月 23 日 An internet-based logistics management system for enterprise chainsAbstractThis paper presents an Internet-Based Logistics Management System to coordinate and disseminate tasks and related information for solving the heterogeneous vehicle routing problem using appropriate heuristic techniques, for use in enterprise chain net works. Its architecture involves a JAVA Web applet equipped with interactive communication capabilities between peripheral software tools. The system was developed in distributed software fashion technology for all computer platforms utilizing a Web browser, focusing on the detailed road network of Athens and the needs of the Athens Central Food Market enterprises. Keywords: Decision support system; e-Logistics; Transportation; Vehicle routing problem1. IntroductionEnterprise chains are the business model of the present and future regarding markets that involve small and medium company sizes. Clearly, grouping activities towards a focused target facilitates an understandably improved market penetration guaranteed by a successful trade mark of a leading company in the field. Several collaboration models that basically include franchising are introduced as a part of this integrated process. When such a network is introduced in order to exploit a commercial idea or business initiative and subsequently expanded as market penetration grows, several management issues arise regarding the operations of the entire network. Such a network is the ideal place for organizing and evaluating in a more centralized way several ordinary operations regarding supply chain and logistics In fact, tools developed for organizing management processes and operational needs of each individual company, can be developed in a more centralized fashion and the services provided by the tool can be offered to each network member to facilitate transactions and tackle operations similarly. Web-based applications are an ideal starting place for developing such applications. Typically such systems serve as a central depot for distributing common services in the field of logistics. The commercial application is stored in a central server and services are provided for each member of the group. A prototype of such a server is described in previous work . This paper presents the completed internet system that is installed in the central web server of the Athens Central Food Market that deals with the integrated problem of distribution for 690 companies that comprise a unique logistics and retail chain of enterprises. The needs of each company are underlined and the algorithms developed are described within the unified internet environment. The problem solved and services provided for each company is the one involving distribution of goods through a heterogeneous fleet of trucks. New insights of the heuristics employed are provided. A characteristic case study is presented to illustrate the effectiveness of the proposed approach for a real-world problem of distribution through the detailed road network of Athens.2. Distribution through heterogeneous vehicle fleetsThe fleet management problem presented in this paper requires the use of a heterogeneous fleet of vehicles that distribute goods through a network of clients. Therefore, the system was designed in order to automatically generate vehicle routes (which vehicles should de-liver to which customers and in which order), using rational, quantitative, spatial and non-spatial information and minimizing simultaneously the vehicle cost and the total distance travelled by the vehicles, subject to the following constraints:? each vehicle has a predetermined load capacity, typically different from all other vehicles comprising the fleet (heterogeneous nature),? the capacity of a vehicle cannot be exceeded,? a single vehicle supplies each customers demand,? the number of vehicles used is predetermined2.1. NeighborThe neighbor is defined as a blend of the most favorable local search moves that transforms one solution to another. In particular, in its taboo search iteration the type of move adopted is decided stochastically. A predefined probability level is assigned to each move type. After that, it is decided whether the move operation is performed within a single route or between different routes, once more stochastically. This time, for both operations, the probability level is assigned a value of 50%. Subsequently, the best neighbor that the selected move implies is computed. The move types employed are the 2-Opt move (Bell et al., 1983), the 1–1 Exchange move, the1–0 Exchange, on both single route and different routes.2.2. Short-term memoryShort-term memory, known as taboo list, is the most often used component of taboo search. Taboo list is imposed to restrict the search from revisiting solutions that were considered previously and to discourage the search process from cycling between subsets of solutions. For achieving this goal, attributes of moves, more precisely the reversals of the original ones, are stored in a taboo list. The reversal moves that contain attributes stored in taboo list are designated taboo and they are excluded from the search process. Regarding the taboo search variant implemented, these attributes are the nodes involved in the move (all the moves used in this method can be characterized by indicating only two nodes) and the corresponding routes where these nodes belong to. The number that arcs’ mobility is restricted is known as taboo list size or taboo tenure. The management of the taboo list is achieved by removing the move which has been on the taboo list longest.2.3. Aspiration criterionThe aspiration criterion is a strategy for overriding the short-term memory functions. The taboo search method implemented, uses the standard aspiration criterion: if a move gives a higher quality solution than the best found so far, then the move is selected regardless its taboo status.Taboo Search algorithm terminates when the number of iterations conducted is larger than the maximum number of iterations allowed.3. Developing the internet-based application toolWeb services offer new opportunities in business landscape, facilitating a global marketplace where business rapidly create innovative products and serve customers better. Whatever that business needs is, Web services have the flexibility to meet the demand and allow to accelerate outsourcing. In turn, the developer can focus on building core competencies to create customer and shareholder value. Application development is also more efficient because existing Web services, regardless of where they were developed, can easily be reused.Many of the technology requirements for Web services exist today, such as open standards for business to-business applications, mission-critical transaction platforms and secure integration and messaging products. However, to enable robust and dynamic integration of applications, the industry standards and tools that extend the capabilities of to days business-to-business interoperability are required. The key to taking full advantage of Web services is to understand what Web services are and how the market is likely to evolve. One needs to be able to invest in platforms and applications today that will enable the developer to quickly and effectively realize these benefits as well as to be able to meet the specific needs and increase business productivity.Typically, there are two basic technologies to be implemented when dealing with internet-based applications; namely server-based and client-based. Both technologies have their strong points regarding development of the code and the facilities they provide. Server-based applications involve the development of dynamically created web pages. These pages are transmitted to the web browser of the client and contain code in the form of HTML and JAVASCRIPT language. The HTML part is the static part of the page that contains forms and controls for user needs and the JAVASCRIPT part is the dynamic part of the page. Typically, the structure of the code can be completely changed through the intervention of web server mechanisms added on the transmission part and implemented by server-based languages such as ASP, JSP, PHP, etc. This comes to the development of an integrated dynamic page application where user desire regarding problem peculiarities (calculating shortest paths, execute routing algorithms, transact with the database, etc.) is implemented by appropriately invoking different parts of the dynamic content of such pages. In server-based applications all calculations are executed on the server. In client-based applications, JAVA applets prevail. Communication of the user is guaranteed by the well-known JAVA mechanism that acts as the medium between the user and code.Everything is executed on the client side. Data in this case have to be retrieved, once and this might be the time-consuming part of the transaction.In server-based applications, server resources are used for all calculations and this requires powerful server facilities with respect to hardware and software. Client-based applications are burdened with data transmission (chiefly related to road network data). There is a remedy to that; namely caching. Once loaded, they are left in the cache archives of the web browser to be instantly recalled when needed.In our case, a client-based application was developed. The main reason was the demand from the point of view for personal data discretion regarding their clients. In fact, this information was kept secret in our system even from the server side involved.Data management plays major role in the good function of our system. This role becomes more substantial when the distribution takes place within a large and detailed road network like this of a major complex city. More specifically, in order to produce the proposed the routing plan, the system uses information about:? the locations of the depot and the customers within the road network of the city (their co-ordinates attached in the map of the city),? the demand of the customers serviced,? the capacity of the vehicles used,? the spatial characteristics of road segments of the net work examined,? the topography of the road network,? the speed of the vehicle, considering the spatial characteristics of the road and the area within of which is moved,? the synthesis of the company fleet of vehicles.4. Case studyThe system developed was used in the Central Food Market of Athens, Greece. The specific Market involves 2 area of 320,000m in the south-west region of Athens greater area at the boundary of port of Greece. This Market is basically a hybrid of two submarkets; the first one involves fresh vegetables and fruits and the second one fresh meat. A Central Food Market is an organization that involves numerous small enterprises that sell and distribute fresh food products, chiefly fresh vegetables, fruits fish and meat. It is considered to be the place where supply and demand together and where prices determined in conditions of transparency and open exchange. Every day, the market is visited by thousands of operators and traders who consider it the best place in which to carry out their transactions. The market is used by companies specializing in the food sector, traditional retailers, the city markets, supermarkets, hypermarkets, hotel and catering establishments.The fresh vegetables and fruits market involves 690 small and medium enterprises that cover an area of 27,100m, while the Meat market involves 105 small 2 and medium enterprises that cover an area of 6050m. As a complementary area to the Markets, Athens Central Food Market has a Services and Warehouses Area, to serve the growing economic activity generated by the Food Unit. Cash的第一項是新鮮蔬菜和水果，第二個鮮肉。阿中央糧食市場是一個組織，涉及眾多的小企業(yè)，銷售和分發(fā)新鮮食品，主要是新鮮蔬菜，水果，魚和肉。它被認(rèn)為是地方供求走到一起，在價格中的透明度和公開交換條件決定的。每天，市場是由訪問的運營商和貿(mào)易商誰認(rèn)為這是最好的地方，進行他們的交易數(shù)以千計。市場是利用在糧食部門的專業(yè)公司，傳統(tǒng)的零售商，在城市市場，超市，大賣場，酒店和餐飲設(shè)施。新鮮的蔬菜和水果市場，涉及 690 中小型企業(yè)，涵蓋了 21700 平方米面積，而肉類市場涉及 105 個小型和中小型企業(yè)，涵蓋了 6050 平方米領(lǐng)域。作為補充的市場領(lǐng)域，雅典環(huán)副食品批發(fā)市場的服務(wù)業(yè)和倉庫區(qū)，為日益增長的經(jīng)濟活動所產(chǎn)生的食品股。現(xiàn)購自運，采購中心，分銷和物流，倉儲，裝卸和包裝，可租用冷庫，汽車服務(wù)、所有的服務(wù)運營商需求。對于高效率的物流市場的需求，需要專業(yè)化和投資 （車，冷藏庫等） ，以具有競爭力和提供的服務(wù)水平要求越來越多。每一天，這個市場提供了一個復(fù)雜的水果和蔬菜的選擇，在產(chǎn)品的品種和發(fā)行量巨增，這使得它的各種中，最大的水果和蔬菜市場，在希臘和歐洲最大的之一。雅典中央市場響應(yīng)了高效挑戰(zhàn)和可靠地服務(wù)于希臘最重要的糧食部門，提供蔬菜，水果，肉類，在衛(wèi)生和安全條件的肉類產(chǎn)品無與倫比的多種。在肉類市場關(guān)注的是，不僅分布，而且與生產(chǎn)。許多農(nóng)民直接參與雅典中央市場，因為它積極推動與原產(chǎn)地和產(chǎn)品質(zhì)量認(rèn)證證書面額。雅典中央市場設(shè)施包括約 500 個停車位。應(yīng)用程序可在互聯(lián)網(wǎng)地址 http://www.okaa.gr/router/default.asp，通過安全 Cookie 的入口。該系統(tǒng)在適當(dāng)?shù)木幋a在一個封裝的網(wǎng)頁，通過該組織的 Web 服務(wù)器的用戶訪問了Java applet 的形式。有報道說，考慮到了用戶需求數(shù)的限制。應(yīng)用程序必須緊湊，方便用戶，輸入的數(shù)據(jù)，將特定的企業(yè)的關(guān)注不能是透明的其他方面，包括組織和備用卡車司機等。