Vol. 27 · No. 4

The problems of determining the maximum cardinality of an independent set of vertices and the minimum cardinality of a maximal independent set of vertices of a graph are known to be NP-complete. We provide efficient algorithms for finding these values for path graphs of trees.

Medical diagnostics elaboration many times is a distributed and cooperative work, which involves more medical human specialists and different medical systems. Recent results described in the literature prove that medical diagnosis problems can be solved efficiently by large-scale medical multiagent systems. Cooperative diagnosing of medical diagnosis problems by large-scale multiagent systems makes the diagnoses elaborations easier and may increase the accuracy of elaborated diagnostics. The purpose of the study described in this paper consists in the development of a novel large-scale hybrid medical diagnosis system called LMDS. The LMDS system is composed from physicians, medical expert system agents developed in our previous works and medical ICMA agents. Medical ICMA agents represent a novel class of agents with the ICMA architecture developed in our previous works, endowed with medical diagnosis capability. The main novelty of the LMDS system consists in the novel classes of agent members of the system and the manner in which the members of the system contribute to the problems solving. Each diagnostics can be elaborated cooperatively by more members of the system. The diagnosis system can solve difficult medical diagnosis problems whose solving must be discovered cooperatively by the members of the system. Many difficult medical problem solving requires medical knowledge that cannot be detained by a single physician or a medical computational system. Simulations prove the correctness in operation of the LMDS system.

We consider an n-ary random Boolean function f such that Pr[f( tilde alpha)=1] allowbreak=p for tilde alphain 0,1 n and study its geometric model, the so called interval graph. The interval graph of a Boolean function was introduced by Sapozhenko and has been used in construction of schemes realizing Boolean functions. Using this model, we estimate the number of maximal intervals intersecting a given maximal interval of a random Boolean function and prove that the asymptotic bound on the logarithm of the number is (1+arphi(n))łog 2łog 1/pn cdotłog 2 n, where arphi(n) rightarrow 0 as n rightarrow infty.

In this paper the design and implementation of AHyCo (Adaptive Hypermedia Courseware), a web-based learning management system based on adaptive hypermedia, is described. AHyCo consists of a domain model, a student model, an adaptive model and a collaborative model. AHyCo supports interaction between students and content by using adaptive hypermedia and online tests. Particular attention is given to the design of the collaborative functionality which enables automatic grouping of students based on various criteria. Furthermore, student to student and student to teacher interaction is supported through asynchronous communication (forum). File sharing and inter-group grading and evaluation modules were introduced into the collaborative module as well enticing interaction between students across groups.

The Semantic Web is a recent initiative to expose semantically rich information associated with Web resources to build more intelligent Web-based systems. Recently, several projects have embraced this vision and there are several successful applications that combine the strengths of the Web and of semantic technologies. However, Semantic Web still lacks a technology, which would provide the needed scalability and integration with existing infrastructure. In this paper we present our ongoing work on a Semantic Web repository, which is capable of addressing complex schemas and answer queries over ontologies with large number of instances. We present the details of our approach and describe the underlying architecture of the system. We conclude with a performance evaluation, which compares the current state-of-the-art reasoners with our system.

Software engineering aims at increasing quality and reliability while decreasing the cost of the software. Testing is one of the most time-consuming phases of the software development lifecycle. Improvement in software testing results in decrease in cost and increase in quality of the software. Automation in software testing is one of the most popular ways of software cost reduction and reliability improvement. In our work we propose a system called XML-based automatic test data generation that generates the test data automatically according to the given data definition. We also proposed a test data definition language to describe the test data to be generated. This system reduces the testing time compared to manual test data generation and increases the testing reliability compared to the random test data generation by eliminating meaningless test data.