近年來，網路服務在學術研究及企業領域中變得愈來愈重要。目前網路服務在學術研究發展，大部份都是著重技術層面的議題，而忽略了它的經濟效益。很多服務提供者所提供的網路服務其功能性大都雷同，因此網路服務品質可以幫助服務需求者去選擇適當的網路服務。但是服務需求者也許有部份不滿意服務的品質，又因為目前的服務導向架構中缺少了協商機制，以至於雙方無法達成交易。
因此，我們在服務導向架構中，提出一個具有協商能力的網路服務選擇機制，其主要是價格與服務品質之間的協商與讓步，讓服務需求者與服務提供者共同達到最大的經濟效益。

The researches in Web services have become more and more important in the academia and industry. Current researches of Web services architectures mainly focus on technological aspects, but the economic benefits of Web services architectures are often neglected. Many service providers offer Web services with the same or similar functionalities, but Quality of Service (QoS) is a good indicator to support the service requesters in selecting appropriate Web services.
However, service requesters might be partially dissatisfied with the QoS and price proposed by service providers. Because of no negotiation mechanism on QoS and price of the specific Web service between providers and requesters, it is difficult for the requesters to get the satisfactory services.
In our research, we propose a negotiation-capable Web services selection mechanism which is built on the extended Service Oriented Architecture (SOA). The negotiation subjects are non-functional parameters such as price and Quality of Service (QoS) attributes for the Web services transaction. The service requester can select QoS and provisioning price, and then negotiates a best value-for-money Web service with the service provider. The objective of negotiation process is to pursue win-win outcomes between profits of service providers and enhancing effectiveness of service requesters.

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