Distributed Corba-based Ship Management And On-line Query System

The economy of Macau is a typical export-oriented economy. Foreign trade is the lifeblood of Macau's economy. After China joins the World Trade Organization (WTO), transit trade in Macau will increase. However, the shipping industry in Macau today is still under the stage of manual operation, without fully utilizing computer management. Making use of Internet to open up services is even out of the question. If the local shipping companies do not improve work efficiency and strengthen their competitiveness, they will be substituted by foreign companies.Hence, this thesis brings up the idea of a distributed shipping management and web enquiry system based on the techniques of CORBA. The system is constructed by using the distributed-processing techniques of CORBA. Under the multi-tier structure of CORBA, the existing business requirements are fulfilled. Its cross-platform flexibility is used to allow the business information systems to cope with the new way of joint operation, business consolidation and future development. The front-end part of this system is Web-based or Windows-based. The middleware uses Delphi's CORBA techniques. The back-end part uses MS SQL Server's database to store system and user data. Delphi is used as the tool to develop the client-server programs, shortening the system development time. With the scalability and reliability of the middleware in enhancing the system running simultaneously in multiple clients, the system can achieve the following:Dynamic Load Balancing - When a client request is received, the middleware will automatically allocate the request to the idlest server, thus balancing the work load of all servers and efficiently utilizing all resources.Fault Tolerance - When a server hangs, the middleware will automatically change the path of the client request to a normal running server, providing a non-stop service. This increases the stability of the system.This thesis focuses on the following points:1. System architecture based on CORBA: By comparing different types of distributed-processing techniques, suggested the use of CORBA's multi-tier architecture to develop a cross-platform, distributed shipping management and web enquiry system.2. Core services of CORBA: Study the accomplishment of Event Service, Naming Service in order to improve system efficiency and allow developers to perform system upgrade and maintenance.3. Discuss the methods of using WebSnap to connect CORBA servers so that software applications can be reused. Describe the deployment of IIS to enhance the functionality of web servers.4. Web enquiry and dynamic web page techniques: Describe the principles and steps to accomplish web enquiry and dynamic web page using WebSnap, and how to achieve dynamic web page automatic creation through ActiveScript-object web language inside Delphi's IntraWeb component.