Informatica

The main scientific problems investigated in this paper deal with the problem of multiple criteria evaluation of the quality of the main components of e-learning systems, i.e., learning objects (LOs) and virtual learning environments (VLEs). The aim of the paper is to analyse the existing LO and VLE quality evaluation methods, and to create more comprehensive methods based on learning individualisation approach. LOs and VLEs quality evaluation criteria are further investigated as the optimisation parameters and several optimisation methods are explored to be applied. Application of the experts' additive utility function using evaluation criteria ratings and their weights is explored in more detail. These new elements make the given work distinct from all the other earlier works in the area.

It is well known, the voice segments and coincident data packets are not equally valued and significant for decoding and comprehension of speech signal. Some lost segments may only slightly worsen audible quality, while others cause strong distortion of the speech signals. Despite this, the feature of different importance of different voice segments in current generation of digital voice transmission systems is not fully used. There is a fundamental problem with discrimination of different importance and value of voice frames. In this paper the concept “of value of voice frame” is introduced, the metric and means for evaluation and measurement of voice frame value are proposed and also results of the measurements of voice frames value are presented.

In the present paper, the neural networks theory based on presumptions of the Ising model is considered. Indirect couplings, the Dirac distributions and the corrected Hebb rule are introduced and analyzed. The embedded patterns memorized in a neural network and the indirect couplings are considered as random. Apart from the complex theory based on Dirac distributions the simplified stationary mean field equations and their solutions taking into account an ergodicity of the average overlap and the indirect order parameter are presented. The modeling results are demonstrated to corroborate theoretical statements and applied aspects.

In this paper, we propose a new ID-based threshold signature scheme from the bilinear pairings, which is provably secure in the random oracle model under the bilinear Diffie–Hellman assumption. Our scheme adopts the approach that the private key associated with an identity rather than the master key of PKG is shared. Comparing to the-state-of-art work by Baek and Zheng, our scheme has the following advantages. (1) The round-complexity of the threshold signing protocol is optimal. Namely, during the signing procedure, each party broadcasts only one message. (2) The communication channel is optimal. Namely, during the threshold signing procedure, the broadcast channel among signers is enough. No private channel between any two signing parties is needed. (3) Our scheme is much more efficient than the Baek and Zheng scheme in term of computation, since we try our best to avoid using bilinear pairings. Indeed, the private key of an identity is indirectly distributed by sharing a number xID∈ $\mathbb{Z}^{*}_{q}$, which is much more efficient than directly sharing the element in the bilinear group. And the major computationally expensive operation called distributed key generation protocol based on the bilinear map is avoided. (4) At last, the proactive security can be easily added to our scheme.

Business rules are relatively new addition in the field of Enterprise Resource Planning (ERP) systems, which are kind of business information systems, development. Recently some relevant enhancements of existing business information systems engineering methods were introduced, although there are still open issues of how business rules may be used and improve qualitative and quantitative attributes of such kind of information systems. The paper discusses existing business information systems engineering issues arising out of using business rules approach. The paper also introduces several ways of business rule involvement aiming at ensuring ERP systems development agility based on running researches in the field also carried out by the authors.

The widespread use of the XML format for document representation and message exchange has influenced techniques for data integration in last years. A development of various XML languages, methods and tools gave rise to so called XML technology. Enterprise Information Integration (EII) requires an accurate, precise and complete understanding of the disparate data sources, the needs of the information consumers, and how these map to the business concepts of the enterprise. Any integration takes place in context of an Enterprise Information System (EIS). In the paper we explain various approaches to EII, its architectures as well as its association to Enterprise Application Integration (EAI). We introduce basic features and issues of EII and justify why XML technology contributes to finding sufficiently powerful support for tools for enabling EII. In particular, a database approach to XML provides a universal solution enabling to construct tools for achieving EII. In the paper we present some features of the XML technology, mainly its database part, and show how it is usable in EII.

Semantic Web is envisioned as semantic description of data and services enabling unambiguous computerized interpretation. Thanks to semantic description, computers can perform demanding tasks such as automation of discovery and access to heterogeneous data sources. Although this is possible with the existing technologies, combination of web services technology, ontologies and generative programming methods makes this simpler and more efficient. This paper presents the model for dynamic generation of web services for data retrieval from heterogeneous data sources using ontologies. Emphasis is on dynamic generation of web services customized to a particular user based on the request defined by ontology. The paper also describes a prototype of the model implementation. Some advantages of our approach over other approaches are also provided.

Interoperability is becoming an area with high focus both at national and cross-national level. This paper presents an assessment of the maturity levels of cross-national interoperability activities within the governmental domain in 13 nations. This analysis includes an assessment of national enterprise architecture programs and national interoperability collaborations, in order to find out whether these serve as important precursors for engaging in cross-national interoperability collaborations. This paper document the importance of national activities as a precursor for engaging in cross-national interoperability collaboration by demonstrating the relation between the maturity of national and cross-national activities.

In the context of enterprise engineering, strategic planning, information systems engineering, and software engineering activities should be tightly integrated. Traditional, interview-based requirements gathering and elicitation techniques are suited for this aim not enough well and often lead to the violation of the strategic alignment. The vision-driven requirements engineering has been proposed to solve this problem. The paper contributes to the further development of vision-driven requirements engineering techniques. It proposes a methodical framework that defines a complete scheme to organize different level requirements and allows to flowdown requirements from business to software level preserving their business-orientation.

Inter-Organizational Workflow (IOW) aims at supporting the collaboration between several autonomous and heterogeneous business processes, distributed over different enterprises or organizations. Coordination of these processes is a fundamental issue that has been mainly addressed in a static context, but it still remains open in a dynamic one such as the Internet in which IOW applications are more and more enacted nowadays. In such a context, Multi-Agent Systems (MAS) are known to be a natural solution for modeling IOW since they provide adequate abstractions and specific mediators to cope with IOW coordination. Consequently, this paper provides an agent-based model for coordinating business processes involved in a dynamic IOW. This model is a triplet (E, M, R). E is the set of coordinated entities. It corresponds to the different business processes that may be published, discovered or deployed by IOW partners. M is the media supporting coordination. It is a multi-agent architecture compliant with the Workflow Management Coalition architecture and integrating specific components devoted to coordination issues. Finally, R is the set of rules governing the coordination. In our context, R is described through an organizational model aiming at structuring the interaction among the coordinated entities and the different components of the architecture.