_the eyeball web to the transaction web从眼球网络到交易网站课件

Katia Sycara Intelligent Software Agents and Web Technologies Lab Carnegie Mellon University /softagents/ Autonomous Semantic Web Services ISRI-Seminar-05 Talk Overview The Vision Requirements and Challenges Web Services Semantic Web Multi Agent Systems (MAS) Semantic Web Services OWL-S Future Directions 2 2 ISRI-Seminar-05 From the Internet to the Semantic Web Old World : “The eye-ball Web” The architecture of the Web is geared towards delivering information visually (Internet filled with human readable information) New World: “The Semantic Web” The content of the Web becomes computer intelligible (Internet filled with machine understandable information) Source: IBM 3 3 ISRI-Seminar-05 From the Internet to Web Services Old World : “The eye-ball Web” The architecture of the Web is geared towards delivering information visually (Internet filled with human readable information) New World: “The transactional Web” The architecture of the Web geared towards exchanging information between applications (Internet filled with executables) Source: IBM 4 4 ISRI-Seminar-05 From the Internet to Semantic Web Services Old World : “The eye-ball Web” The architecture of the Web is geared towards delivering information visually (Internet filled with human readable information) New World: “The Coordination Web” The architecture of the Web geared towards applications that intelligibly coordinate information exchanges (Internet filled with machine understandable executables) Source: IBM 5 5 ISRI-Seminar-05 From the Internet to Autonomous Semantic Web Services Old World : “The eye-ball Web” The architecture of the Web is geared towards delivering information visually (Internet filled with human readable information) New World: “The Agent Web” The architecture of the Web geared towards goal directed applications that intelligibly and adaptively coordinate information and action (Internet filled with context- aware and self organizing agents) Source: IBM 6 6 ISRI-Seminar-05 The Integration Challenge Integrate multiple independent and heterogeneous Data repositories Processes Applications Ensure Semantic equivalence of equivalent concepts Performance Communication of “semantic” agreements Dynamism: real time access works accurately Flexibility: systems enter and leave integration 7 7 ISRI-Seminar-05 The Integration Past and Future? Numerous solutions to date (since the 70s): Tool driven Data driven Process driven Model driven Web services 8 8 ISRI-Seminar-05 Web Services - A New Paradigm? Web Services heralded as: “ self-contained, self-describing, modular applications that can be published, located, and invoked across the Web” Which will allow on the fly composition of new functionality through the use of loosely coupled reusable software components decomposition and distribution of large-scale processing tasks into component tasks executed simultaneously across many devices “Web services are expected to revolutionize our life in much the same way as the Internet has during the past decade or so.” (Gartner) 9 9 ISRI-Seminar-05 So what is new about Web Services? Component-Based ModelWeb Services Model Tightly coupled software applications (high dependencies between systems) Loosely coupled software applications (low dependencies between applications) Mainly designed for processes within the enterprise Mainly designed for processes across enterprises Uses different protocols and technologies (e.g., Microsoft DCOM, CORBA) Uses standard protocols and technologies (e.g., XML, SOAP, WSDL, HTTP) Web Services do for programs what the Web did for Documents 1010 ISRI-Seminar-05 Requirements and Challenges Information and action integration across the Web (currently the user is the “glue”) System integration/interoperability Web-wide (within and across organizations) Semantic Interoperability Consistency of behavior of long running transactions (both for e -commerce and e-science) in the face of partial, distributed failures Dynamic and goal-directed discovery, interaction and composition of applications across the Web Tension between the “anarchy” of the Web and the requirements for reliable, consistent, trusted transactions of e- commerce and e-science 1111 ISRI-Seminar-05 Current State: Web Services Standards SOAP: XML based web services communication protocol Limitations Unbounded message format Has no communicative speech acts (cannot determine intention of actors or type of the message) WSDL: Structured mechanism to describe a WS interface Abstract operations that a Web Service can perform Format of messages it can process Protocols it can support Physical bindings to URIs and protocols Limitations No semantics for message sequencing and correlation No semantics for message content 1212 ISRI-Seminar-05 Current State: Web Services Standards (cnt.) BPEL: Description of how Web Services are composed Flow Model describes the structure of the business process in terms of activities of process steps and data and control links Global Model Describes interaction between provider and requester Mappings between internal operations and WSDL port types Limitations No IOPEs Allows execution of a manually constructed composition UDDI: Directory Service for Web Services Limitations: keyword searches, limited capability search 1313 ISRI-Seminar-05 Tackling Semantic Interoperability Lack of Semantic Interoperability is a major hurdle for Discovery Different terms used for advertisements and requests Invocation Different specs for messages and WS interface Understanding Interpreting the results returned by the Web service Composing Services Reconciling private goals with goals of the WS Negotiating contracts Info Integration; Business Process Automation; Tasking RDF Model “Semantic Matching of Web Services Capabilities.“ In Proceedings of the 1st International Semantic Web Conference (ISWC2002), 2002 Thing Vehicle CarTruck SedanCoupe subsumeplug-inexact Mid-SizeLuxury Price 3636 ISRI-Seminar-05 CMU UDDI is publicly available at /matchmaker or on SemWebCentral /projects/mm-client/ A variant of the CMU UDDI is in use at the NTT UDDI Business Registry (The main public UDDI in Japan) (see Kawamura et al 2003, 2004) Semantic Web Services Integration of OWL-S Matchmaker and UDDI PublishPublish Port PortInquiry Inquiry Port Port Green Pages Yellow Pages White Pages UDDIUDDI Business RegistryBusiness Registry CapabilityCapability Port Port OWL-SOWL-S Matching Matching EngineEngine CMU OWL-S Matching engine has been integrated within UDDI server CMU UDDI server provides Normal UDDI Publish/Inquiry ports Complete interoperability with any UDDI Client Capability Port provides OWL-S based capability requests (see Srinivasan et al 2004) OWL-S Profile has been mapped to UDDI data structure OWL-S Web services can be advertised in UDDI as any other Web service (see Paolucci et al 2002) 3737 ISRI-Seminar-05 Semantic Web Services Process Model Process Model Describes how a service works: internal processes of the service Specifies service interaction protocol Specifies abstract messages: ontological type of information transmitted Facilitates Web service invocation Composition of Web services Monitoring of interaction 3838 ISRI-Seminar-05 Semantic Web Services Definition of Process A Process represents a transformation (function). It is characterized by four parameters Inputs: the inputs that the process requires Preconditions: the conditions that are required for the process to run correctly Results: a process may have different outcomes depending on some condition Condition: under what condition the result occurs Outputs: the data that results from the execution of the process Effects: real world changes resulting from the execution of the process 3939 ISRI-Seminar-05 Semantic Web Services Composite Processes Composite Processes specify how processes work together to compute a complex function Composite processes define Control Flow Specify the temporal relations between the executions of the different sub-processes Data Flow Specify how the data produced by one process is transferred to another process 4040 ISRI-Seminar-05 Semantic Web Services Example of Composite Process Sequence BookFlight Depart Arrive Flights Airline AirlineFlight Perform Get Flights Flight Perform Select Flight Flights Control Flow Links Specify order of execution Data-Flow Links Specify transfer of data Perform statements Specify the execution of a process 4141 ISRI-Seminar-05 Semantic Web Services Control Flow Processes can be chained to form a workflow OWL-S supports the following control flow constructs Sequence/Unordered: to represent a list of processes that are executed in sequence or random order Conditionals: if-then-else statements Loops: while and repeat-until statements Multithreading and synchronization: split process in multiple threads, and rendezvous (joint) points Non-deterministic choices: (arbitrarily) select on process of a set 4242 ISRI-Seminar-05 Semantic Web Services Data Flow Dataflow allows information that is transferred from process to process. OutputInput: The information produced by one process is transferred to another in the same control construct Input Input: The information received by a composite process is transferred to the sub-processes OutputOutput: The information produced by a subprocess is transferred to a super- process 4343 ISRI-Seminar-05 Semantic Web Services Service Grounding Service Grounding Provides a specification of service access information. Service Model + Grounding give everything needed for using the service Builds upon WSDL to define message structure and physical binding layer 4444 ISRI-Seminar-05 Semantic Web Services Mapping OWL-S /WSDL 1.1 Operations correspond to Atomic Processes Input/Output messages correspond to Inputs/Outputs of processes 4545 ISRI-Seminar-05 Semantic Web Services Example of Grounding Sequence BookFlight Depart Arrive Flights Airline AirlineFlight Perform Get Flights Flight Perform Select Flight Flights Get Flights Op Depart Arrive Flights WSDL Airline Flight Select Flight op Flights 4646 ISRI-Seminar-05 Semantic Web Services Result of using the Grounding Invocation mechanism for OWL-S Invocation based on WSDL Different types of invocation supported by WSDL can be used with OWL-S Clear separation between service description and invocation/implementation Service description is needed to reason about the service Decide how to use it Decide how what information to send and what to expect Service invocation may be based on SOAP and XSD types The crucial point is that the information that travels on the wire is the same information used in the ontologies Allows any web service to be represented using OWL-S For example: A 4747 ISRI-Seminar-05 Semantic Web Services Mapping OWL-S to WSDL OWL-S invocation is based on the Grounding Map atomic processes into WSDL operations Use XSLT to map between XML Schema data structures and Ontological Information Invocation procedure totally separated from semantic description of Web service Invocation may be modified without changing semantic description Any Web service can be described in OWL-S without modifying the WSDL description of the service Amazons Web service has been described in OWL-S maintaining Amazons XML-Schema data types 4848 ISRI-Seminar-05 Semantic Web Services OWL-S Virtual Machine OWL-S VM a generic processor for the OWL-S Process Model Uses OWL-S to represent service descriptions It can interact with any OWL-S Web service Based on the Process Model formal semantics (Ankolekar et al 2002) Implements grounding mapping to WSDL Uses OWL to represent information to exchange between Web services Actively adopts logic inference to reason about OWL-S and OWL ontologies Exploits Web services technology such as Axis and WSIF for actual invocation and message exchange Anupriya Ankolekar, Frank Huch, Katia Sycara. “Concurrent Execution Semantics for DAML-S with Subtypes.“ In The First International Semantic Web Conference (ISWC), 2002. Massimo Paolucci, Anupriya Ankolekar, Naveen Srinivasan and Katia Sycara, “The DAML-S Virtual Machine,“ In Proceedings of the Second International Semantic Web Conference (ISWC), 2003, 4949 ISRI-Seminar-05 Semantic Web Services Architecture of CMU OWL-S VM SOAP Provider Web Service Description WSDL OWL-S Process Model OWL-S Ground ing OWL Inference Engine Jess OWL Jess KB Process Model Execution Rules Grounding Execution Rules OWL-S Processor Axiss Web Service Invocation Framework OWLS WebServiceInvoker Webservice Invocation Web Services Jena APPLICATION Requester OWL-S VM 5050 ISRI-Seminar-05 Semantic Web Services WSDL2OWL-S Converter Provides partial conversion from WSDL Web service descriptions to OWL-S descriptions Generates complete specification of Grounding Partial Specification of the Process Model Including Atomic Processes Partial Model of the Profile Resulting models require additional annotations to include semantic descriptions Combined with Java2WSDL to provide Java2OWL- S Web Based Interface /wsdl2owls/ Download: /projects/wsdl2owl-s/ 5151 ISRI-Seminar-05 Semantic Web Services Process Model of AWS SearchSearch ReserveReserve ShopShop WSDL2OWL-S used to generate OWL-S for Amazons Web Service OWL-S VM used to interact with Amazon Web service 5252 ISRI-Seminar-05 Semantic Web Services Performance OWL-S VM client on OWL-S VM client on browsing+reserving taskbrowsing+reserving task Analyzed data by computing:Analyzed data by computing: Time required by OWL-S Time required by OWL-S VM to execute Process ModelVM to execute Process Model Time required for data Time required for data transformation to fit Amazon transformation to fit Amazon requirementsrequirements Time required to invoke Time required to invoke an operation on Amazonan operation on Amazon 98 runs total over 4 days in varying load 98 runs total over 4 days in varying load conditionsconditions Results in millisecondsResults in milliseconds VMData TrsfmInvocation Average percentage 83 3% 156 5% 2797 92% Strd dev1071461314 OWL-S VM Data Transformation Amazon Invocation 5353 ISRI-Seminar-05 Autonomous Semantic Web Services Problem of Composition No single Web service may achieve all goals of an agent Composition is the process of chaining results from different Web services automatically Planning problem How do the Web services fit together? Interoperation problem How does the information returned fit together? 5454 ISRI-Seminar-05 Autonomous Semantic Web Services CMU Composition Architecture Exploits Retsina Architecture for WS composition OWL-S/UDDI Matchmaker for discovery Retsina planner to control the agent Use interleaving of planning and execution to allow communication while planning OWL Reasoner OWL-S Virtual Machine to communicate and invoke Web Services Katia Sycara, Massimo Paolucci, Anupriya Ankolekar and Naveen Srinivasan, “Automated Discovery, Interaction and Composition of Semantic Web services,“ Journal of Web Semantics, Volume 1, Issue 1, September 2003, pp. 27-46 5555 ISRI-Seminar-05 Autonomous Semantic Web Services Example of Composition Used in a number of applications: travel domain, supply chain management Supports composition and execution of Web Services Connection with autonomous agent technology in collaboration with 5656 ISRI-Seminar-05 Semantic Web Services Security and Policies No standard OWL-S representation for Security and Policies has been published yet But experimentation already under going Adoption of a solution will depend on WS security standards Security Experiments with representing security capability/requirements for discovery Representing security information in Process Model. Policies: Experiments combining OWL-S and Rei Rei statements included in Process Model to constrain the use of a Web service (see Kagal 2004) Recent work on Formal Verification of OWL-S Process Models provides a way to certify adherence to a policy Grit Denker, Lalana Kagal, Tim Finin, Massimo Paolucci, Naveen Srinivasan and Katia Sycara, “Security For DAML Web Services: Annotation and Matchmaking“ In Proceedings of the Second International Semantic Web Conference (ISWC 2003), Sandial Island, Fl, USA, October 2003, pp 335-350. Anupriya Ankolekar, Massimo Paolucci, and Katia Sycara Spinning the OWL-S Process Model - Toward the Verification of the OWL-S Process Models In Proceedings of Workshop on Semantic Web Services: Preparing to Meet the World of Business Applications (ISWC 2004) 5757 ISRI-Seminar-05 Semantic Web Services Production cycle of OWL-S WS Developer generates Java code S