Ontologies are shared models of a domain that encode a view which is common to a set of different parties. Contexts are local models that encode a party's subjective view of a domain. In this paper we show how ontologies can be contextualized, thus acquiring certain useful properties that a pure shared approach cannot provide. We say that an ontology is contextualized or, also, that it is a contextual ontology, when its contents are kept local, and therefore not shared with other ontologies, and mapped with the contents of other ontologies via explicit (context) mappings. The result is Context OWL (C-OWL), a language whose syntax and semantics have been obtained by extending the OWL syntax and semantics to allow for the representation of contextual ontologies.

Abstract. Semantic coordination, namely the problem of finding an agreement on the meaning of heterogeneous semantic models, is one of the key issues in the development of the Semantic Web. In this paper, we propose a new algorithm for discovering semantic mappings across hierarchical classifications based on a new approach to semantic coordination. This approach shifts the problem of semantic coordination from the problem of computing linguistic or structural similarities (what most other proposed approaches do) to the problem of deducing relations between sets of logical formulae that represent the meaning of concepts belonging to different models. We show how to apply the approach and the algorithm to an interesting family of semantic models, namely hierarchical classifications, and present the results of preliminary tests on two types of hierarchical classifications, web directories and catalogs. Finally, we argue why this is a significant improvement on previous approaches. 1

In this paper, we outline the relation between Knowledge Management (KM) as an application area on the one hand, and software agents as a basic technology for supporting KM on the other. We start by presenting characteristics of KM which account for some drawbacks of today's -- typically centralized -- technological approaches for KM. We argue that the basic features of agents (social ability, autonomy, re- and proactiveness) can alleviate several of these drawbacks. A classification schema for the description of agent-based KM systems is established, and a couple of example systems are depicted in terms of this schema. The paper concludes with questions which we think research in Agent-mediated Knowledge Management (AMKM) should deal with.

Knowledge management can exploit the new opportunities offered by computer networks and pursue its goals by sharing knowledge among the members of virtual communities. Secure distributed knowledge management introduces new requirements. First, participants should not give up their autonomy to prohibit access to knowledge to users they do not trust, even when the users satisfy the security rules of the virtual community. Second, the rules of policies for managing knowledge in a secure way do not concern only what knowledge the users are prohibited or permitted to access, but they also concern which regulations their members are allowed or obliged to enforce. This is a challenge, because rules refer usually to the actions of users and not to other rules which are obligatory or permitted to adopt. In this paper we introduce a model of policies for secure knowledge management in virtual communities which satisfies the above requirements. The methodology we use is to model distributed knowledge management by means of normative multi-agent systems. Each member of the virtual community is a normative system which interacts with other members and poses prohibitions and permissions about access to its knowledge. 1 1

The problem of computing/discovering mappings across heterogeneous schemas (e.g., classifications, taxonomies, catalogs, data types definitions) is one of the key issues in the development of the Semantic Web. In this paper, we argue that this problem can be viewed as a problem of semantic coordination (namely, as a problem of coordinating the meaning of portions of schemas through a collection of semantic mappings), and propose a new method for discovering semantic mappings called CTXMATCH. This approach shifts the problem of semantic coordination from the problem of computing linguistic or structural similarities (what most other proposed approaches do) to the problem of deducing relations between sets of logical formulae that represent the meaning of elements belonging to different schema. We show how to apply the method to an interesting family of schemas (namely hierarchical classifications), and present the results of preliminary tests on two types of hierarchical classifications, web directories and catalogs. Finally, we argue why this is a significant improvement on previous approaches.

Advertising plays a key role in service oriented recommendation over a peer-to-peer network. The advertising problem can be considered as the problem of finding a common language to denote the peers' capabilities and needs. Up to now the current approaches to the problem of advertising revealed that the proposed solutions either a#ect the autonomy assumption or do not scale up the size of the network. We explain how an approach based on language games can be e#ective in dealing with the typical issue of advertising: do not require ex-ante agreement and to be responsive to the evolution of the network as an open system. In the

Abstract: The goal of this article is to explore some of the main reasons that sustain a distributed approach to Knowledge Management, and this will be done, first, showing how, according to very different theoretical disciplines, knowledge diversity is proposed as the very source of organizational innovation and adaptability; second providing some evidence coming from major applicative domains; third proposing some considerations on the role of technology.

Knowledge management solutions relying on central repositories sometimes have not met expectations, since users often create knowledge ad-hoc using their individual vocabulary and using their own individual IT infrastructure (e.g., their laptop). To improve knowledge management for such decentralized and individualized knowledge work, it is necessary to, first, provide a corresponding decentralized IT infrastructure and to, second, deal with specific problems such as security and semantic heterogeneity. In this paper, we describe the technical peerto -peer platform that we have built and summarize some of our experiences applying the platform in case study for coopetitioning organizations in the tourism sector.

The Distributed Knowledge Management (DKM) approach tries to overcome problems deriving from a typical outcome of traditional Knowledge Management (KM) solutions: the creation of a unique conceptualization of corporate knowledge (e.g. an ontology or a unique system of classification) which does not allow autonomy of organizational units and the coexistence of di#erent conceptual schemas (e.g. points of view or perspectives). This new approach takes strongly into account local heterogeneity, and looks at complex knowledge-based organizations as constellations of local organizational units which manage knowledge in an autonomous way, exchanging it with other units through meaning negotiation/coordination processes. In a DKM system each autonomous unit is reified by a Knowledge Node (KN), a useful abstraction which allows us to identify, within organizations, people who manage knowledge according to a local conceptual schema and a personalized system of artifacts. In this paper, a new methodology is described and then used to unveil Knowledge Nodes in a case study: Impresa Pizzarotti & C. S.p.A., a complex Italian building industry. It is argued that the resulting Distributed Knowledge Management system might be implemented within the firm with a high probability of success, because the system of Knowledge Nodes (discovered through this methodology) reflects the perspective and the way in which organizational units usually manage their knowledge.

In this paper, we explore an architecture, called K-Trek, that enables mobile users to travel across knowledge distributed over a large geographical area (ranging from large public buildings to a national park). Our aim is providing, distributing, and enriching the environment with location-sensitive information for use by agents on board of mobile and static devices. Local interactions among KTrek devices and the distribution of information in the larger environment adopt some typical peer-to-peer patterns and techniques. We introduce the architecture, discuss some of its potential knowledge management applications, and present a few experimental results obtained with simulation.