Real-time Web Services-based Components

With the rapid development of the distributed computing technology, the activity of the company and government rely more and more on Internet. Traditional distributed object model like CORBA, DCOM, RMI are not suitable for extremely heterogeneous Internet environment. Web Service is a new kind of Service Oriented Architecture in recent years. It defines a group of standard protocols for interface define, method call, component register based on Internet and implement of all kinds of applications.In the electric business market, it is not reality for all the partners to take the same model based on a certain language and platform. Web Service, which has good adaptation and flexibility, combines the advantage of component-oriented method and Web technology, and makes use of standard network protocols and XML data format to communicate. In the huge virtual computing environment of Internet, any system that supports these standards can be located dynamically and communicate with the other Web Services on the network, and any client can call any services without noticing where they are. This breaks through the limitations of the traditional distributed computing model on the areas of communication and applied range, and it permits companies and persons construct and distribute global applications quickly and cheaply.With standards like SOAP, UDDI, and WSDL being adopted by all major Web Service players, a whole range of Web Services - covering the financial services, high-tech, and media and entertainment ~ are being currently developed. As most of the Web Services are going to need to establish and adhere to standards, QoS (Quality of Service) will become an important selling and differentiating point of these services.In the series of requirements to guarantee Web Service QoS, the real time requirements do not stand out, and that the Web Service environments do not provide such standard support currently. But nowadays the enterprises need offer the rightmessage to the right people at the right time, and the modern electronic commerce need the business on demand. These requirements need real time QoS stringently. Further more, collaboration systems, alarm systems, manufacture systems, transmission systems and so on, all need available real time QoS.This paper discusses the real time problem of Web Service's QoS. Through study the research work of the Web Service QoS internationally, this paper analyses several implement methods of Web Service QoS parameter definition and compares these implement technologies. Base on these this paper brings forward a real time QoS parameter definition model for Web Service component and uses XML files to define the real time QoS parameter of Web Service.On the base of analysis the real time middleware system this paper gives an instance to compute the schedulability and thread priority of the task using EDF scheduling algorithm. It computes the deadline of the service requirements by the QoS parameter defined by XML files carried in the requests of the Web Service SOAP packets and maps the request priority to the end system priority according to priority mapping policy. Finally this paper gives a real time extended method for the .Net thread pool.This paper is divided into seven chapters:Chapter One is the introduction segment. It outlines the research background and the main work of this paper.Chapter Two is the summary of Web Service technology. First it expounds the concept and architecture model of Web Service, then it introduces the Web Service protocol stack, and at last it compares the two main Web Service application frameworks.Chapter Three is the relevant technology of Web Service QoS. This chapter introduces the extended protocol stack about the Web Service QoS and the current overseas research work. It also describes the real time requirement of Web Service and the corresponding market analysis.Chapter Four analyses the definition methods of Web Service QoS parameter internationally, and gives a real time instance of it.Chapter Five explains the...