专业英语课程论文

专业英语课程论文（工业工程 09 级）姓名：学号：教师：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 11 Exchange move, the10 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的第一项是新鲜蔬菜和水果，第二个鲜肉。阿中央粮食市场是一个组织，涉及众多的小企业，销售和分发新鲜食品，主要是新鲜蔬菜，水果，鱼和肉。它被认为是地方供求走到一起，在价格中的透明度和公开交换条件决定的。每天，市场是由访问的运营商和贸易商谁认为这是最好的地方，进行他们的交易数以千计。市场是利用在粮食部门的专业公司，传统的零售商，在城市市场，超市，大卖场，酒店和餐饮设施。新鲜的蔬菜和水果市场，涉及 690 中小型企业，涵盖了 21700 平方米面积，而肉类市场涉及 105 个小型和中小型企业，涵盖了 6050 平方米领域。作为补充的市场领域，雅典环副食品批发市场的服务业和仓库区，为日益增长的经济活动所产生的食品股。现购自运，采购中心，分销和物流，仓储，装卸和包装，可租用冷库，汽车服务、所有的服务运营商需求。对于高效率的物流市场的需求，需要专业化和投资 （车，冷藏库等） ，以具有竞争力和提供的服务水平要求越来越多。每一天，这个市场提供了一个复杂的水果和蔬菜的选择，在产品的品种和发行量巨增，这使得它的各种中，最大的水果和蔬菜市场，在希腊和欧洲最大的之一。雅典中央市场响应了高效挑战和可靠地服务于希腊最重要的粮食部门，提供蔬菜，水果，肉类，在卫生和安全条件的肉类产品无与伦比的多种。在肉类市场关注的是，不仅分布，而且与生产。许多农民直接参与雅典中央市场，因为它积极推动与原产地和产品质量认证证书面额。雅典中央市场设施包括约 500 个停车位。应用程序可在互联网地址 http:/www.okaa.gr/router/default.asp，通过安全 Cookie 的入口。该系统在适当的编码在一个封装的网页，通过该组织的 Web 服务器的用户访问了Java applet 的形式。有报道说，考虑到了用户需求数的限制。应用程序必须紧凑，方便用户，输入的数据，将特定的企业的关注不能是透明的其他方面，包括组织和备用卡车司机等。