Tuesday, May 29, 2012 Towards Automatic Non-Deterministic Web Service Composition Markou, G. & Refanidis, I. Dept. of Applied Informatics, University of Macedonia, Greece ICIW Web Services-based Systems & Applications IV

Tuesday, May 29, 2012 In Summary Introduction Related Work o Method of Choice o Use of Standards o Online o Evaluation Proposed Approach Evaluation o Quantitative criteria o Use case scenarios Conclusion ICIW Web Services-based Systems & Applications IV2/31 o Application o Registry o Web Service Editor o Translation between AI & Web Service languages o Manual Web Service Composition module o Automatic Web Service Composition module

Tuesday, May 29, 2012 Introduction Related Work o Method of Choice o Use of Standards o Online o Evaluation Proposed Approach o Application o Registry o Web Service Editor o Translation between AI & Web Service languages o Manual Web Service Composition module o Automatic Web Service Composition module Evaluation o Quantitative criteria o Use case scenarios Conclusion ICIW Web Services-based Systems & Applications IV3/31

Tuesday, May 29, 2012 Motivation Difficult to expect from a human user /experts to manually complete the goal of a Web Service Composition (WSC) o Number of Web Services (WSs) is growing continuously  discovery phase more difficult o Ever-changing environment: WSs can change interfaces or even part of their usage multiple times throughout their lifespan o Always possible that their execution is not successful ICIW Web Services-based Systems & Applications IV4/31

Tuesday, May 29, 2012 System Goals - Functionalities: Online Registry / Advertisement / Semantic search of Web Services Editing of Web Services Translation/ mapping between AI & Web Service languages Manual Web Service composition module Automatic Web Service composition module Evaluation based on o Quantitative criteria o Use case scenarios ICIW Web Services-based Systems & Applications IV5/31

Tuesday, May 29, 2012 Introduction Related Work o Method of Choice o Use of Standards o Online o Evaluation Proposed Approach o Application o Registry o Web Service Editor o Translation between AI & Web Service languages o Manual Web Service Composition module o Automatic Web Service Composition module Evaluation o Quantitative criteria o Use case scenarios Conclusion ICIW Web Services-based Systems & Applications IV6/31

Tuesday, May 29, 2012 Method of Choice (1/2) Method of choice? Use of standards? ICIW Web Services-based Systems & Applications IV7/31 Most widespread: AI planning Diverse o OWL-S / PDDL widely used o Other standards (e.g., WSMO) o Proprietary formats Perhaps most notable is Sirin, et al. (2004) o From WSC problem (described in OWL-S) to HTN o Composite process that can be decomposed to simpler ones  Simple processes being atomic WSs o Reduces complexity of the planning process o Cannot cope with non-determinism  o Planner-dependent 

Tuesday, May 29, 2012 Method of Choice (2/2) AI planning also used in Hoffmann, et al. (2009) o Treats the application of a WS as a belief update operation o Identifies tractable special cases of WSC  Allow for a compilation into planning under uncertainty o Subsequent use of existing conformant planner o PDDL-like problem descriptions  o No standardized WS description  ICIW Web Services-based Systems & Applications IV8/31

Tuesday, May 29, 2012 Use of Standards Klusch, Gerber & Schmidt (2005) and Hatzi, et al. (2011) rely on translation of OWL-S descriptions to PDDL problems o Klusch, Gerber & Schmidt (2005):  Outputs modified PDDL files (in XML)   Does not have evaluation on WSC problems  o Hatzi, et al. (2011) tackles uncertainty with re-planning module  o Both only address WSC problem, not other stages  ICIW Web Services-based Systems & Applications IV9/31

Tuesday, May 29, 2012 Online YaWSA (Macdonald, 2007) o Only web-based WSC system in literature with running demo o Only implemented a WSC process (no registry, view WSs’, etc) o No longer available for public use  Prototype web-based WSC system described in Du, Song, and Munro (2006) o Supporting multiple phases of WSC o Public link to running demo of their implementation is not provided  ICIW Web Services-based Systems & Applications IV10/31

Tuesday, May 29, 2012 Evaluation Literature suggests a gap in the evaluation process of the current WSC systems o Many simply evaluate their methodology on a single case study, without referring to quantitative criteria, e.g., Chen, Xu, and Reiff- Marganiec (2009), McDermott (2002), McIlraith and Son (2002) Notable exceptions: o Hoffmann, et al. (2009) : Two artificial benchmarks with different encodings and planners o Hatzi, et al. (2011): Single use case, with different number of WSs  Test collection combination of hand-tailored atomic WSs and entire domains of OWL-S Service Retrieval Test Collection (OWL-S TC) o Kona, et al. (2008): Three versions of a single use case, each suited for a mode of their WSC algorithm  Test collection: Modified version of the 2006 WS-Challenge ICIW Web Services-based Systems & Applications IV11/31

Tuesday, May 29, 2012 Introduction Related Work o Method of Choice o Use of Standards o Online o Evaluation Proposed Approach o Application o Registry o Web Service Editor o Translation between AI & Web Service languages o Manual Web Service Composition module o Automatic Web Service Composition module Evaluation o Quantitative criteria o Use case scenarios Conclusion ICIW Web Services-based Systems & Applications IV12/31

Tuesday, May 29, 2012 Proposed Approach - Application ICIW Web Services-based Systems & Applications IV13/31 User registration Initial screen Based on Google Web Toolkit (GWT):

Tuesday, May 29, 2012 Registry (1/2) Core of the application is based on iServe o Open platform for publishing and discovering services o WSs are semantically described in OWL-S, not Minimal Service Model o Used its web-based application for  Browsing  Querying  Uploading services o Populated the registry with version 4.0 of OWL-S TC o Made several improvements to its interface and functionality ICIW Web Services-based Systems & Applications IV14/31

Tuesday, May 29, 2012 Registry (2/2) ICIW Web Services-based Systems & Applications IV15/31 Web Service details Inline operations Semantic search alternatives

Tuesday, May 29, 2012 Proposed Approach – WS Editor ICIW Web Services-based Systems & Applications IV16/31 XML Editor with syntax highlighting Pre-defined OWL-S templates

Tuesday, May 29, 2012 Translation between AI & WS Languages AI planning language: PDDL, the de facto planning language o Specifically, NuPDDL  Compatible with PDDL2.1, retaining most of it  Capable of modeling non-deterministic action effects (one of, unknown) WS semantic description language: OWL-S, most widely used o Heavily influenced from planning languages, such as PDDL Partial mapping from OWL-S to PDDL exists o Part of it straightforward:  ServiceProfile input parameters  identically named ones of PDDL action  hasPrecondition/ hasEffect parameters  precondition/ effect of action o Conversion of non-physical knowledge from OWL-S to PDDL problematic  Introduction of new predicate in PDDL domain? ICIW Web Services-based Systems & Applications IV17/31

Tuesday, May 29, 2012 Manual WSC Module Under implementation  Based on PetalsBPM  Modification from BPMN 2.0 editor to suit OWL-S WSC functionalities  To be compared with automatic WSC module (ease of use, speed, etc) ICIW Web Services-based Systems & Applications IV18/31

Tuesday, May 29, 2012 Automatic WSC Module Future work – Basic directions: o WSs may fail to execute correctly, e.g.,  Unavailability of an atomic WS involved in the plan  Output of their successful execution is not the expected one o Generate plans tackling the most influential and likely contingencies o Proposed solution based on contingent planning  Produce seed plan  Examine for significant/ likely points of failure  Add conditional branches  Re-planning module will be integrated ICIW Web Services-based Systems & Applications IV19/31

Tuesday, May 29, 2012 Introduction Related Work o Method of Choice o Use of Standards o Online o Evaluation Proposed Approach o Application o Registry o Web Service Editor o Translation between AI & Web Service languages o Manual Web Service Composition module o Automatic Web Service Composition module Evaluation o Quantitative criteria o Use case scenarios Conclusion ICIW Web Services-based Systems & Applications IV20/31

Tuesday, May 29, 2012 Quantitative Criteria Criteria to be considered: o Number of Web Services considered for WSC o Preprocessing time (parsing of ontologies’ concepts, etc) o Transformation time (of WS domain to PDDL one) o Planning time (to output a successful plan) o Optimality of the outputted plans (least WSs used to achieve the required goal) ICIW Web Services-based Systems & Applications IV21/31

Tuesday, May 29, 2012 Use Case Scenarios Based on OWL-S TC Semantic Web Services v. 4.0 (PDDL) o Each scenario uses a subset of descriptions of an OWL-S TC domain o A few semantic WS descriptions were added for testing purposes, and some were modified Each scenario with increasing non-determinism & complexity ICIW Web Services-based Systems & Applications IV22/31

Tuesday, May 29, 2012 Movie Database Scenario (1/2) 1)Movie database search using a (partial) movie title o Based on Communication domain: 58 semantic WSs in total o Fully deterministic - Serialized composite WS output o Retrieve comedy films with titles similar to user input o Output:  Movie titles  Pricing information (tax-free price, recommended price, etc) ICIW Web Services-based Systems & Applications IV23/31

Tuesday, May 29, 2012 Movie Database Scenario (2/2) Composite Web Service (created through Manual WSC module) ICIW Web Services-based Systems & Applications IV24/31

Tuesday, May 29, 2012 Online Bookstore Scenario (1/2) 2)Online bookstore product purchase o User wants to purchase a book from an specific online bookstore with a preferred method of payment o Preferences regarding method of payment o Based on Education domain: 285 semantic WSs in total o Non-deterministic output  Different outcomes:  Output if book in stock:  Addition of book in shopping cart  Purchase with the specified method of payment  Output information regarding it, such as its author  No output if book not in stock ICIW Web Services-based Systems & Applications IV25/31

Tuesday, May 29, 2012 Online Bookstore Scenario (2/2) Composite Web Service (created through Manual WSC module) ICIW Web Services-based Systems & Applications IV26/31

Tuesday, May 29, 2012 Camera Search Scenario (1/2) 3)Camera search and purchase o User want to purchase an analog SLR model; willing to settle for other ones if it is not in stock  User preference towards specific model  More than one sellers exist o Based on Economy domain: 359 semantic WSs in total o Possible iteration in output Web Service  Since more than one sellers exist, if product not available at one, check another  If product not found in any of the sellers, try with other versions (digital SLR, simple compact cameras) ICIW Web Services-based Systems & Applications IV27/31

Tuesday, May 29, 2012 Camera Search Scenario (2/2) Composite Web Service (created through Manual WSC module) ICIW Web Services-based Systems & Applications IV28/31

Tuesday, May 29, 2012 Introduction Related Work o Method of Choice o Use of Standards o Online o Evaluation Proposed Approach o Application o Registry o Web Service Editor o Translation between AI & Web Service languages o Manual Web Service Composition module o Automatic Web Service Composition module Evaluation o Quantitative criteria o Use case scenarios Conclusion ICIW Web Services-based Systems & Applications IV29/31

Tuesday, May 29, 2012 Conclusion Current WSC approaches, in general: o Do not deal with inherent non-determinism in WSC domain o Are not online, despite WS’ use & nature being web-oriented o Do not evaluate their methodology using well defined scenarios or test sets  Improvements have been made recently Our final system is intended to be the first online and open source system supporting multiple phases of WSC Presented scenarios provide efficient way of evaluation o Can be used by other WSC works as a common test bed ICIW Web Services-based Systems & Applications IV30/31

Tuesday, May 29, 2012 Thank you for your attention! Questions? ICIW Web Services-based Systems & Applications IV31/31

Tuesday, May 29, 2012ICIW Web Services-based Systems & Applications IV32/31 Extra Slides

Tuesday, May 29, 2012 References: Referenced papers: E. Sirin, B. Parsia, D. Wu, J. Hendler, and D. Nau, “HTN planning for web service composition using SHOP2”, J. Web Semant., vol. 1, no. 4, Oct. 2004, pp J. Hoffmann, P. Bertoli, M. Helmert, and M. Pistore, “Message-based web service composition, integrity constraints, and planning under uncertainty: a new connection”, J. Artif. Intell. Res, vol. 35, May 2009, pp M. Klusch, Α. Gerber, and M. Schmidt, “Semantic web service composition planning with OWLS-Xplan”, Proc. 1st International AAAI Fall Symposium on Agents and the Semantic Web, Nov O. Hatzi, D. Vrakas, M. Nikolaidou, et al., “An integrated approach to automated semantic web service composition through planning”, IEEE Trans. Service Computing, April 2011, pp A. Macdonald, “Service composition with hyper-programming”. Technical Report, University of St Andrews, X. Du, W. Song, and M. Munro, “Using common process patterns for semantic web services composition”, Proc. 15th International Conference on Information Systems Development (ISD’06), Sept K. Chen, J. Xu, and S. Reiff-Marganiec, “Markov-HTN planning approach to enhance flexibility of automatic web service composition”, Proc. IEEE International Conference on Web Services (ICWS'09), July 2009, pp D.V. McDermott, “Estimated-regression planning for interactions with web services”, Proc. Sixth International Conference on Artificial Intelligence Planning Systems (AIPS ’02), April 2002, pp S. McIlraith and T. Son, “Adapting Golog for composition of semantic web services”, Proc. 8th International Conference on Principles of Knowledge Representation and Reasoning (KR2002), April 2002, pp S. Kona, A. Bansal, M.B. Blake, and G. Gupta, “Generalized Semantics-Based Service Composition”, Proc. IEEE International Conference on Web Services (ICWS’08), Sept ICIW Web Services-based Systems & Applications IV