Scientific Journals and Yearbooks Published at SAS

Article List

Computing and Informatics


Volume 23, 2004, No. 2

Content:


  On the use of the Choquet Integral for the Collaborative Creation of Learning Objects
JUAN MANUEL DODERO, MIGUEL-ANGEL SICILIA, CAMINO FERNANDEZ

Collaborative work, multi-agent systems, fuzzy sets, aggeregation operations, learning objects, Choquet integral

Computer-supported collaborative knowledge creation is the continuous process of development of knowledge assets, where produced knowledge has to be assessed by the developers, taking into account a set of criteria that may keep some interdependencies. This work poses an approach for collaborative creation of learning objects in a Web-based, educational context, based upon a coordination protocol and an aggregation mechanism. The coordination protocol allows the continuous consolidation of opinions issued about the learning objects produced by a number of authors. During certain steps of the protocol, an aggregation process is performed that takes into account the inter-dependence among criteria. The results of using the Choquet integral as an aggregation operator are compared to the usual aggregation procedure based upon weighted arithmetic means.

Computing and Informatics. Volume 23, 2004, No. 2: 101-113.

 
  Context and Virtual Communities In a Firm
PATRICK BREZILLON

Information technology, decision making, context, shared context, social network, virtual community

This paper revisits a case study about the consequences on the decision-making process of the introduction of IT in a newspaper firm. We consider the case study in the light of the paradigms of context, social network and virtual community. We point out that it is possible to provide a global picture of the consequence of the IT introduction in a firm and explain the dynamic of the information-management processes in such an enterprise. A first result is that making context explicit-especially shared contexts-improves notably the collaborative decision making processes in the firm. A second result is to show different interests of the simultaneous consideration of the paradigms of context, social network and virtual community.

Computing and Informatics. Volume 23, 2004, No. 2: 115-131.

 
  A Dynamic Adaptive Replica Allocation Algorithm in Mobile Ad Hoc Networks
ZHENG JING, LU XIENG, YANG KAN, WANG YIJE

MANET, replica allocation, read-write pattern, stable neighbor

In mobile ad hoc networks (MANET), nodes move freely and the distribution of access requests changes dynamically. Replica allocation in such a dynamic environment is a significant challenge. The communication cost has become a prominent factor influencing the performance of replica allocation in the MANET environment. In this paper, a dynamic adaptive replica allocation algorithm that can adapt to the nodes motion is proposed to minimize the communication cost of the object access. When changes occur in the access requests of the object or the network topology, each replica node collects access requests from its neighbors and makes decisions locally to expand the replica to neighbors or to relinquish the replica. This algorithm dynamically adjusts the replica allocation scheme towards a local optimal one. To reduce the oscillation of replica allocation, a statistical method based on history information is utilized to choose stable neighbors and to expand the replica to relatively stable nodes. Simulation results show that our algorithms efficiently reduce the communication cost of object access in MANET environment.

Computing and Informatics. Volume 23, 2004, No. 2: 133-156.

 
  Ontologies in a Multi-Agent System for Automated Scheduling
EVELIO J. GONZALEZ, ALBERTO J. HAMILTON, LORENZO MORENO, ROBERTO L. MARICHAL, JONAY TOLEDO

Multi-agent systems, ontologies, scheduling

Multi-Agent Systems (MAS) have been successfully used in a wide range of applications such as robotics and e-commerce, and in particular in planning and scheduling. The aim of this paper is to present the interesting features that the use of ontologies in MAS offers. As an example, the development of a MAS for automated planning and scheduling in a University Research Group Scenario is shown in this paper. In this scenario, researchers are frequently proposed to attend internal meetings about several subjects such as lessons planning or research evaluations. Scheduling and negotiating meeting details such as time and location becomes highly complicated as the number of intended attendees increases. Moreover, there are usually conflicts about the use of some common resources such as portable computers or projectors. As can be seen, the scheduling problem that the MAS solves is very easy. So having solved it is not what is important about this paper. In contrast, what is important is the potential which a scheduler can schedule for the items whose description, for example, is on the web, and can read on it (without knowing a~priori) the logic of how the scheduling can be done.

Computing and Informatics. Volume 23, 2004, No. 2: 157-177.

 
  Independence Number in Path Graphs
MARTIN KNOR, LUDOVIT NIEPEL

Path graph, independence number, iterated line graph, graph dynamics, (non)deterministic algorithm

In the paper we present results, which allow us to compute the independence numbers of $P_2$-path graphs and $P_3$-path graphs of special graphs. As $P_2(G)$ and $P_3(G)$ are subgraphs of iterated line graphs $L^2(G)$ and $L^3(G)$, respectively, we compare our results with the independence numbers of corresponding iterated line graphs.

Computing and Informatics. Volume 23, 2004, No. 2: 179-187.

 
  Market Mechanism for Dynamic Resource Management In Computational Grid
LI CHUNLIN, LI LA YUAN

Grid, resource management, market, agent

This paper presents a market mechanism for dynamic resource allocation in computational grid. Grid market is described that consists of two economic agent types; it allows agents representing various grid resources to coordinate their resource allocation decisions without assuming a priori cooperation. The grid task agents buy resources to complete tasks. Grid resource agents charge the task agents for the amount of resource capacity allocated. Grid resource allocation problem is presented as grid user utility optimization. Given grid resource agent's pricing policy, the task agent optimization problem is to complete its job as quickly as possible when spending the least possible amount of money. This paper provides a resource allocation and pricing algorithm. Experiments are made to compare the performance of the price-directed resource allocation with conventional Round-Robin allocation.

Computing and Informatics. Volume 23, 2004, No. 2: 189-203.