INFORMATICS RESEARCH PROPOSAL REALTING LCC TO SEMANTIC WEB STANDARDS. Nor Amizam Jusoh (S ) Supervisor: Dave Robertson

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1 INFORMATICS RESEARCH PROPOSAL REALTING LCC TO SEMANTIC WEB STANDARDS Nor Amizam Jusoh (S ) Supervisor: Dave Robertson Abstract: OWL-S as one of the web services standards has become widely used by many researchers because of its abilities in making the Web Services tasks automation easier. But however, this standard is lack of coordination between agents. In this paper, we will looked at some reviews on one of the service standards, the OWL-S and how it s being used in terms of agents communication and interoperability. We will also looked at the capability of LCC as a language for coordinating distributed processes and then attempt to map a subset of LCC to OWL-S. Based on this analysis we will do an evaluation for both language and standard and, in response, produce an extended LCC as well as the extended LCC interpreter. The main contributions of this research are to understand the correspondence between one or more Semantic Web service standards (e.g. OWL-S) and LCC and also to introduce LCC as a new language for coordination. 1.0 Introduction Semantic Web and Web Services are two emerging trends that are reshaping the Web today. The Semantic Web, which it s content, is consumed by computer programs in addition to humans while Web Services provides a set of standards and practices for the remote use of computer applications. The combination of these two trends is sometimes referred to as Intelligent Web Services [1]. These computer programs known as agents are sophisticated computer programs that act autonomously on behalf of their users, across open and distributed environments, to solve a growing number of complex problems. Increasingly, however, applications require multiple agents that can work together. A multi-agent system (MAS) is a loosely coupled network of software agents that interact to solve problems that are beyond the individual capacities or knowledge of each problem solver [2]. Semantic markup itself is intended to solve the problem of coordination among heterogeneous agents. However, it is far from clear how this can be achieved. The problem of coordinating agents with semantic markup introduces the issues associated with semantic interoperability and OWL-S has been proposed as one of the solution. But this however, it is likely that this will be an open issue for some time to come [3]. Web

2 services annotation with the OWL-S ontologies will make the Web Services tasks automation easier and the tasks are discovery, execution composition and interoperation [8]. But however, this standard seems to not having coordination capability between agents which going to perform all these tasks. To solve this coordination problem requires some description of the focus of coordination and one way of doing this is by using policy languages [4]. This research will present an approach known as Lightweight Coordination Calculus to solve the problem of coordination among agents in Semantic webs. The rest of the paper is organized as follows. In section 2.0 describes some key aspects of the LCC, OWL-S and WSMO that relate in this research. Section 3.0 is very important because it tells how I am planning to tackle the research problem. It will provide the work plan and describe the activities necessary for the completion of the project. Section 4.0 describes the results generated from this research and all this will be concluded in Section Background 2.1 LCC [5] has interpreted LCC or Lightweight Coordination Calculus as an extension of the Electronic Institutions framework. It presents an innovative way to define scenes in the framework. LSS allows coordination in an open multi-agent system which requires no middle man to enforce the coordination of agents and this preserves the issue of autonomy. It is possible to describe the message passing behavior of each agent by using the notation described above. This framework allows one agent to tell another agent who is unaware of the first agent exactly how it intends to communicate with it. It is important that each agent conversing in the dialogue must be able to determine the current state of the dialogue. This is achieving by retaining separately in the protocol the instances of the dialogue clauses used by each agent participating in the dialogue. When an agent receives a message, a protocol is attached of the form illustrated above. The agent must unpack the protocol it receives, finding the next moves it is permitted to take and updating the protocol to describe the new state of the dialogue. In other words, each time and agent does something; it marks the script with what it has done and passes it on. When the next agent engages in the conversation, it knows exactly what to do next because the

3 preceding agent has marked the script, retrieving the current state and knows where to pick up where the last agent left off. The work of LCC allows agents to take part in scenarios where it is impossible to define the protocol before hand, allowing agents to communicate in an open multi agent system where the number of agents participating in the interactions has not been predefined. With LCC, there is no centralized control between the agents; no administrative agent is required to synchronize coordination of the agents because the protocol is embedded with the conversation of the agents. Protocols do no longer have to be distributed to all agents that wish to take part in a scene in advance because the protocol that the agents must follow has already embedded within the conversation that takes place between the agents. This means that changes can easily be made without modifying the protocol and having to redefine each and very agent. 2.2 OWL-S In [6], the OWL-S or Semantic Web Service Ontology is to define a set of basic classes and properties for declaring and describing services i.e. ontology for describing Web Services that enable users and software agents to automatically discover, invoke, and compose and monitor Web resources offering services in a wide sense, not focusing on a particular application domain or problem. The development of OWL-S is centered on a set of tasks to be fulfilled, namely the automatic Web Service discovery, invocation, composition, interoperation and execution monitoring. Although OWL-S inherits the foundations of research areas such as planning and agents, it does not explicitly delimitate what principles are applied to the development of the ontology. OWL-S is organized into three modules [9]: A profile which describes Web service capabilities as well as any additional features that help describes the service; A process model which describes the Web service provider s activity, which is how the requester can derive information about service invocation; and A grounding which describes how the abstract information exchanges explained in the process model are mapped to the actual messages that providers and requesters exchange.

4 2.3 WSMO In [7], WSMO or Web Service Modeling Ontology defined as a meta-ontology describing all aspects related to dynamic composition of web services, including dynamic discovery, selection, mediation and invocation. Ontology means a knowledge representation that allows for both automatic reasoning and human understanding. WSMO is based on four concepts: web services, ontologies, goals and mediators. Web services are unit of functionality, offered on the Internet. Every web service has exactly one capability that describes logically what this web service can offer. Goals describe some state that a user wants to achieve. Ontologies are the formal specification the domain knowledge used by both the web service to express its capability and by the goal to express the desired world state. Mediators are used to solve different interoperability problems, for example the differences ontologies used by a web service and a goal. WSMO is a meta-ontology, which describes how to construct ontologies about dynamic composition of web services. An example of such as WSMO-compliant ontology could describe some web service offered by Amazon that can be used to purchase books, as well as the ontology used by the Amazon. 3.0 Description of Methods and Techniques In order to be able to tackle this research problem, few activities necessary for this research have been planned. These activities are divided into 3 stages which are: Extend LCC to include the service specification ideas of OWL-S: This is a language specification issue. There will be a need to study more on LCC and OWL-S to be able to do a mapping from a subset of LCC to OWL-S. Result generated from this will be an extended LCC. Develop an interpreter for an extended LCC: This is a programming issue. There is a need to develop an interpreter for an extended LCC. Apply a benchmark scenario as implemented in [8]: Since our aim is to introduce LCC as a new language for coordination, there is a need to apply the same scenario which will make evaluation process become easier.

5 4.0 Evaluation The evaluation will be done in two ways, an empirical evaluation and analytical evaluation. The empirical evaluation will be conducted by applying a benchmark scenario which in this research is the hotel room reservation scenario. Analytical evaluation will require a comparison of what can and cannot be represented in each language, OWL-S and LCC, in terms of the knowledge represented in each language. There will be an intersection between them but no one will subsume the other. 5.0 Outputs At the end of this research, outputs that we will have would be extended LCC, extended LCC interpreter and also comparison between LCC and OWL-S. 6.0 Research Plan This research will only took about 4 months to be completed. It will starts in May 2005 for analysis stage and finish with dissertation in August Table 1 below is the summarization of the research stages together with its activities involved in each stage and its targeting time of starting and completing. Stage Activity Milestone Stage 1 Familiarization with the LCC system and with one or May 2005 more semantic web service specification standards - the most likely of these currently being OWL-S and WSMO. Stage 2 Defining a mapping from a subset of LCC to OWL- May 2005 S/WSMO. Stage 3 Adapting LCC to OWL-S/WSMO. This will require May 2005 assumptions to be made about the computation to be supported during service location and invocation. It may also require additional language features in LCC. Stage 4 Constructing a version of one of the existing LCC interpreters that is more closely oriented to OWL- S/WSMO (given the experience of previous stages). May 2005 until July 2005

6 Stage 5 Evaluating LCC as a coordination language, compared to OWL-S and/or WSMO, in terms of the variety of June 2005 until July 2005 forms of coordination that may be represented; the compactness of the representation; and the ability to use the representation for performing coordination. Stage 6 Writing dissertation. May 2005 until August 2005 Table 1.0 Project Stages and Milestones 7.0 Conclusion LCC is a language for coordinating distributed processes. It can become one of the standards for web services because of its capability in representing complex coordination between Webs services described in agent style. The main achievements of this research would be the extended LCC and extended LCC interpreter. 6.0 References [1] Toivonen et al, On Describing B2B Processes with Semantic Web Technologies [2] The Intelligent Software Agents Lab [3] Kalfoglou et al. On The Emergent Semantic Web And Overlooked Issues. In 3rd International Semantic Web Conference (ISWC2004) [4] D. Robertson. A Lightweight Coordination Calculus For Agent Systems. In Proceedings of Declarative Agent Languages and Technologies, AAMAS, New York, USA [5] A, Barker. Coordination Is The Key. MRES Dissertation. University Of Edinburgh, January 2004.

7 [6] Ruben Lara, Dumitru Roman, Axel Polleres, and Dieter Fensel. A Conceptual Comparison of WSMO and OWL-S. In Proceedings of the European Conference on Web Services (ECOWS 2004), [7] E. Oren. Semantic Web Services Using WSMO. In Second Annual Research Day 2004, National University of Ireland, Galway, April [8] Aguado et al. Online Design of Events Application trial, Version [9] Katia Sycara, Massimo Paolucci, Julien Soudry, Naveen Srinivasan "Dynamic Discovery and Coordination of Agent-Based Semantic Web Services" IEEE Internet Computing May/June 2004 (Vol. 8, No. 3).