Matteo Baldoni

Verifying the conformance of web services to global interaction protocols: a first step

Global choreographies define the rules that peers should respect in their interaction, with the aim of guaranteeing interoperability. An abstract choreography can be seen as a protocol specification; it does not refer to specific peers and, especially in an open application domain, it might be necessary to retrieve a set of web services that fit in it. A crucial issue, that is raising attention, is verifying whether the business process of some peers, in particular the parts that encode the communicative behavior, will produce interactions which are conformant to the agreed protocol (legality issue). Such issue is tackled by the so called conformance test, which is a means for certifying the capability of interacting of the involved parts: two peers that are proved conformant to a same protocol will actually interoperate by producing a legal conversation. This work proposes an approach to the verification of a priori conformance of a business process to a protocol, which is based on the theory of formal languages and guarantees the interoperability of peers that are individually proved conformant.

Behavior-Oriented Commitment-based Protocols

Ever since the seminal work of Searle, two components of interaction protocols have been identified: constitutive rules, defining the meaning of actions and regulative rules, defining the flow of execution, i.e. the behavior the agent should show. The two parts together define the meaning of the interaction. Commitment-based protocols, however, usually do not account for the latter and, when they do it, they do not adopt a decoupled representation of the two parts. A clear distinction in the two representations would, however, bring many advantages, mainly residing in a greater openess of multi-agent systems, an easier re-use of protocols and of action definitions, and a finer specification of protocol properties. In this work we introduce the notion of behavior-oriented commitment-based protocols, which account both for the constitutive and the regulative specifications and that explicitly foresee a representation of the latter based on constraints among commitments. A language, named 2CL, for writing regulative specifications is also given.

From Tags to Emotions: Ontology-driven Sentiment Analysis in the Social Semantic Web

Affective computing is receiving increasing attention in many sectors, ranging from advertisement to politics. This work, set in a Social Semantic Web framework, presents ArsEmotica, an application software for associating the predominant emotions to artistic resources of a social tagging platform. Our aim is to extract a rich emotional semantics (i.e. not limited to a positive or a negative reception) of tagged resources through an ontology driven approach. This is done by exploiting and combining available computational and sentiment lexicons with an ontology of emotional categories. The information sources we rely upon are the tags by which users annotated resources, that are available through the ArsMeteo platform, and the ontology OntoEmotion, that was enriched by means of our tool with over four hundred Italian emotional words referring to the about eighty-five emotional concepts of the ontology. Tags directly referring to ontological concepts are identified, while potentially affective tags, can be annotated by using the ontology thanks to the spontaneous intervention of the user, in a pure Web 2.0 approach. Finally, the tagged artworks are related with the emerging predominant emotions. Matteo Baldoni Dipartimento di Informatica, Universita degli Studi di Torino e-mail: baldoni@di.unito.it Cristina Baroglio Dipartimento di Informatica, Universita degli Studi di Torino e-mail: baroglio@di.unito.it Viviana Patti Dipartimento di Informatica, Universita degli Studi di Torino e-mail: patti@di.unito.it Paolo Rena Dipartimento di Informatica, Universita degli Studi di Torino e-mail: paolo.rena@gmail.com

Interaction between Objects in powerJava

users by means of access control and keep track of the state of the interaction with each user by means of sessions. The current vision in object orientation, instead, considers attributes and operations of objects as being objective and independent from the interaction with another object, which is sessionless. To introduce these features in the interaction between objects directly in object oriented programming languages, we take inspiration from how access control is regulated by means of roles. Roles allow objects to oer dierent operations depending on the type of the role, of the type and identity of the player of the role, and to define session-aware interaction. We start from a definition of roles given in ontologies and knowledge representation and we discuss how this definition of roles can be introduced in Java, building our language powerJava.

Personalization for the semantic web

Searching for the meaning of the word “personalization” on a popular search engine, one finds twenty-three different answers, including “the process of matching categorized content with different end users based on business rules ... upon page request to a Webserver”, “using continually adjusted user profiles to match content or services to individuals”, and also “real-time tailoring of displays, particularly Web pages, to a specific customers known preferences, such as previous purchases”. A little more generally, personalization is a process by which it is possible to give the user optimal support in accessing, retrieving, and storing information, where solutions are built so as to fit the preferences, the characteristics and the taste of the individual. This result can be achieved only by exploiting machine-interpretable semantic information, e.g. about the possible resources, about the user him/herself, about the context, about the goal of the interaction. Personalization is realized by an inferencing process applied to the semantic information, which can be carried out in many different ways depending on the specific task. The objective of this paper is to provide a coherent introduction into issues and methods for realizing personalization in the Semantic Web.

Reasoning about interaction protocols for customizing web service selection and composition

This work faces the problem of automatic selection and composition of web services, discussing the advantages that derive from the inclusion, in a web service declarative description, of the high-level communication protocol, that is used by the service for interacting with its partners, allowing a rational inspection of it. The approach we propose is set in the Semantic Web field of research and inherits from research in the field of multi-agent systems. Web services are viewed as software agents, communicating by predefined sharable interaction protocols. A logic programming framework based on modal logic is proposed, where the protocol-based interactions of web services are formalized and the use of reasoning about actions and change techniques (planning) for performing the tasks of selection and composition of web services in a way that is personalized w.r.t. the user request is enabled. We claim that applying reasoning techniques on a declarative specification of the service interactions allows to gain flexibility in fulfilling the user preference in the context of a web service matchmaking process.

Programming Rational Agents in a Modal Action Logic

In this paper we describe a language for reasoning about actions that can be used for modelling and for programming rational agents. We propose a modal approach for reasoning about dynamic domains in a logic programming setting. Agent behavior is specified by means of complex actions which are defined using modal inclusion axioms. The language is able to handle knowledge producing actions as well as actions which remove information. The problem of reasoning about complex actions with incomplete knowledge is tackled and the temporal projection and planning problems is addressed; more specifically, a goal directed proof procedure is defined, which allows agents to reason about complex actions and to generate conditional plans. We give a non-monotonic solution for the frame problem by making use of persistency assumptions in the context of an abductive characterization. The language has been used for implementing an adaptive web-based system.

Web-Based Adaptive Tutoring: An Approach Based on Logic Agents and Reasoning about Actions

In this paper we describe an approach to the construction of adaptive tutoring systems, based on techniques from the research area of Reasoning about Actions and Change.This approach leads to the implementation of aprototype system, having a multi-agent architecture,whose kernel is a set of rational agents,programmed in the logic programminglanguage DyLOG. In the prototype that weimplemented the reasoning capabilities of theagents are exploited both to dynamically buildstudy plans and to verify the correctness ofuser-given study plans with respect to thecompetence that the user wants to acquire.

A priori conformance verification for guaranteeing interoperability in open environments

An important issue, in open environments like the web, is guaranteeing the interoperability of a set of services. When the interaction scheme that the services should follow is given (e.g. as a choreography or as an interaction protocol), it becomes possible to verify, before the interaction takes place, if the interactive behavior of a service (e.g. a BPEL process specification) respects it. This verification is known as “conformance test”. Recently some attempts have been done for defining conformance tests w.r.t. a protocol but these approaches fail in capturing the very nature of interoperability, turning out to be too restrictive. In this work we give a representation of protocol, based on message exchange and on finite state automata, and we focus on those properties that are essential to the verification of the interoperability of a set of services. In particular, we define a conformance test that can guarantee, a priori, the interoperability of a set of services by verifying properties of the single service against the protocol. This is particularly relevant in open environments, where services are identified and composed on demand and dynamically, and the system as a whole cannot be analyzed.

A Tableau Calculus for Multimodal Logics and Some (Un)Decidability Results

In this paper we present a prefixed analytic tableau calculus for a class of normal multimodal logics and we present some results about decidability and undecidability of this class. The class is characterized by axioms of the form [t1]...[tn] ?? [s1]...[sm]? called inclusion axioms, where the tis and sj s are constants. This class of logics, called grammar logics, was introduced for the first time by Farinas del Cerro and Penttonen to simulate the behaviour of grammars in modal logics, and includes some well-known modal systems. The prefixed tableau method is used to prove the undecidability of modal systems based on unrestricted, context sensitive, and context free grammars. Moreover, we show that the class of modal logics, based on right-regular grammars, are decidable by means of the filtration methods, by defining an extension of the Fischer-Ladner closure.