@article {18910,
	title = {Information gathering during planning for Web Service composition},
	journal = {Web Semantics: Science, Services and Agents on the World Wide Web},
	volume = {3},
	year = {2005},
	month = {2005/10//},
	pages = {183 - 205},
	abstract = {Hierarchical task network (HTN) based planning techniques have been applied to the problem of composing Web Services, especially when described using the OWL-S service ontologies. Many of the existing Web Services are either exclusively information providing or crucially depend on information-providing services. Thus, many interesting service compositions involve collecting information either during execution or during the composition process itself. In this paper, we focus on the latter issue. In particular, we present ENQUIRER , an HTN-planning algorithm designed for planning domains in which the information about the initial state of the world may not be complete, but it is discoverable through plan-time information-gathering queries. We have shown that ENQUIRER is sound and complete, and derived several mathematical relationships among the amount of available information, the likelihood of the planner finding a plan, and the quality of the plan found. We have performed experimental tests that confirmed our theoretical results and that demonstrated how ENQUIRER can be used for Web Service composition.},
	keywords = {HTN planning, Information gathering, Web Service composition},
	isbn = {1570-8268},
	doi = {10.1016/j.websem.2005.07.001},
	url = {http://www.sciencedirect.com/science/article/pii/S1570826805000168},
	author = {Kuter,Ugur and Sirin,Evren and Parsia,Bijan and Nau, Dana S. and Hendler,James}
}
@article {18905,
	title = {HTN planning for Web Service composition using SHOP2},
	journal = {Web Semantics: Science, Services and Agents on the World Wide Web},
	volume = {1},
	year = {2004},
	month = {2004/10//},
	pages = {377 - 396},
	abstract = {Automated composition of Web Services can be achieved by using AI planning techniques. Hierarchical Task Network (HTN) planning is especially well-suited for this task. In this paper, we describe how HTN planning system SHOP2 can be used with OWL-S Web Service descriptions. We provide a sound and complete algorithm to translate OWL-S service descriptions to a SHOP2 domain. We prove the correctness of the algorithm by showing the correspondence to the situation calculus semantics of OWL-S. We implemented a system that plans over sets of OWL-S descriptions using SHOP2 and then executes the resulting plans over the Web. The system is also capable of executing information-providing Web Services during the planning process. We discuss the challenges and difficulties of using planning in the information-rich and human-oriented context of Web Services.},
	keywords = {HTN planning, OWL-S, SHOP2, Web Service composition, Web services},
	isbn = {1570-8268},
	doi = {10.1016/j.websem.2004.06.005},
	url = {http://www.sciencedirect.com/science/article/pii/S1570826804000113},
	author = {Sirin,Evren and Parsia,Bijan and Wu,Dan and Hendler,James and Nau, Dana S.}
}
