4,537 research outputs found
Introducing Dynamic Behavior in Amalgamated Knowledge Bases
The problem of integrating knowledge from multiple and heterogeneous sources
is a fundamental issue in current information systems. In order to cope with
this problem, the concept of mediator has been introduced as a software
component providing intermediate services, linking data resources and
application programs, and making transparent the heterogeneity of the
underlying systems. In designing a mediator architecture, we believe that an
important aspect is the definition of a formal framework by which one is able
to model integration according to a declarative style. To this purpose, the use
of a logical approach seems very promising. Another important aspect is the
ability to model both static integration aspects, concerning query execution,
and dynamic ones, concerning data updates and their propagation among the
various data sources. Unfortunately, as far as we know, no formal proposals for
logically modeling mediator architectures both from a static and dynamic point
of view have already been developed. In this paper, we extend the framework for
amalgamated knowledge bases, presented by Subrahmanian, to deal with dynamic
aspects. The language we propose is based on the Active U-Datalog language, and
extends it with annotated logic and amalgamation concepts. We model the sources
of information and the mediator (also called supervisor) as Active U-Datalog
deductive databases, thus modeling queries, transactions, and active rules,
interpreted according to the PARK semantics. By using active rules, the system
can efficiently perform update propagation among different databases. The
result is a logical environment, integrating active and deductive rules, to
perform queries and update propagation in an heterogeneous mediated framework.Comment: Other Keywords: Deductive databases; Heterogeneous databases; Active
rules; Update
A logic programming framework for modeling temporal objects
Published versio
A Logical Approach to Cooperative Information Systems
``Cooperative information system management'' refers to the capacity of several computing systems to communicate and cooperate in order to acquire, store, manage, query data and knowledge. Current solutions to the problem of cooperative information management are still far from being satisfactory. In particular, they lack the ability to fully model cooperation among heterogeneous systems according to a declarative style. The use of a logical approach to model all aspects of cooperation seems very promising. In this paper, we deŸne a logical language able to support cooperative queries, updates and update propagation. We model the sources of information as deductive databases, sharing the same logical language to ex- press queries and updates, but containing independent, even if possibly related, data. We use the Obj-U-Datalog (E. Bertino, G. Guerrini, D. Montesi, Toward deductive object data- bases, Theory and Practice of Object Systems 1 (1) (1995) 19±39) language to model queries and transactions in each source of data. Such language is then extended to deal with active rules in the style of Active-U-Datalog (E. Bertino, B. Catania, V. Gervasi, A. Ra aet a, Ac- tive-U-Datalog: Integrating active rules in a logical update language, in: B. Freitag, H. Decker, M. Kifer, A. Voronkov (Eds.), LBCS 1472: Transactions and Change in Login Databases, 1998, pp. 106±132), interpreted according to the PARK semantics proposed in G. Gottlob, G. Moerkotte, V.S. Subrahmanian (The PARK semantics for active rules, in: P.M.G. Apers, M. Bouzeghoub, G. Gardarin (Eds.), LNCS 1057: Proceedings of the Fifth International Con- ference on Extending Database Technology, 1996, pp. 35±55). By using active rules, a system can e ciently perform update propagation among di erent databases. The result is a logical environment, integrating active and deductive rules, to perform update propagation in a cooperative framework
The Evolution of Reaction-diffusion Controllers for Minimally Cognitive Agents
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A Survey of Languages for Specifying Dynamics: A Knowledge Engineering Perspective
A number of formal specification languages for knowledge-based systems has been developed. Characteristics for knowledge-based systems are a complex knowledge base and an inference engine which uses this knowledge to solve a given problem. Specification languages for knowledge-based systems have to cover both aspects. They have to provide the means to specify a complex and large amount of knowledge and they have to provide the means to specify the dynamic reasoning behavior of a knowledge-based system. We focus on the second aspect. For this purpose, we survey existing approaches for specifying dynamic behavior in related areas of research. In fact, we have taken approaches for the specification of information systems (Language for Conceptual Modeling and TROLL), approaches for the specification of database updates and logic programming (Transaction Logic and Dynamic Database Logic) and the generic specification framework of abstract state machine
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Swarm intelligence for autonomous cooperative agents in battles for real-time strategy games
This paper investigates the use the swarm intelligence of honey bees to create groups of co-operative AI for an RTS game in order to create and re-enact battle simulations. The behaviour of the agents are based on the foraging and defensive behaviours of honey bees, adapted to a human environment. The groups consist of multiple model-based reflex agents, with individual blackboards for working memory, with a colony level blackboard to mimic the foraging patterns. An agent architecture and environment is proposed that allows for creation of autonomous cooperative agents. The behaviour of agents is then evaluated and their intelligence is tested using an adaptation of Anytime Universal Intelligence Test
The Political Economy of Globalization â Revisiting Stephen Hymer 50 Years On
We discuss issues pertaining to the political economy of âglobalizationâ, in the context of the seminal contribution by Stephen Hymer. While Hymerâs contribution to the theory of the multinational enterprise (MNE) and foreign direct investment (FDI) is widely recognized, his contribution to the political economy of what he called âmultinational corporate capitalâ has received less attention. In this paper we revisit some of the issues he raised, notably uneven development, global governance and central planning in the context of post-Hymer scholarly thinking and the shifting global landscape. In so doing we also speculate on the challenges and future of globalization.Stephen Hymer, International Political Economy, Institutions, Globalization,Sustainability
Innovation-based Nets as Collective Actors: A Heterarchization Case Study from the Automotive Industry
Cooperation and collaboration between companies represents a key issue within the conceptual framework developed by the IMP Group. However, little attention has been paid to a phenomenon which can result from such collaboration, i.e. collective action. This involves cooperative activities undertaken by a significant number of actors sharing a common aim. This research uses the concept of issue-based net to open new avenues to understand collective action in the context of innovation activities, specifically by analyzing a case study of an innovation-based net in the automotive industry. Two main objectives are addressed in this study: Related to this discussion of different development paths of collective actors, the case study analysis focuses on how issue-based nets emerge and evolve in situations of innovation, specifically, what kind of structure and process issues characterize a heterarchization development path. Furthermore, the analysis addressed how issue-based nets change the positioning of individual member firms, a well as that of the collective actor within the overall network.Innovation, collective actor, issue-based nets, heterarchization, case study, automotive industry
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