Abstract
Nowadays, since many companies decide to implement and publish their core business and outsource other application services over Internet, the number of Web services has dramatically increased. Thus, Web service based dynamic E-Business, as the next evolutionary step of E-Business, becomes an important task in the industry. In many cases, a single service is not sufficient to fulfil the user’s request and services should be combined together. Thus, dynamic composition of Web services to provide considerable flexibility for modifying and extending the operations of E-Business systems during runtime, is one of the recent critical issues. A number of approaches have been presented, to solve this problem. In this paper, we classify the competing approaches to three categories (Workflow-based, XML-based, and Ontologybased), which can be complementary, and describe them. Then, we compare these approaches based on some benchmarks (like QoS, scalability, and correctness).