Computer and Information Science

Security policies have different components; firewall, active directory, and IDS are some examples of these components. Enforcement of network security policies to low level security mechanisms faces some essential difficulties. Consistency, verification, and maintenance are the major ones of these difficulties. One approach to overcome these difficulties is to automate the process of translation of high level security policy into low level security mechanisms. This paper introduces a framework of an automation process that translates a high level security policy into low level security mechanisms. The framework is described in terms of three phases; in the first phase all network assets are categorized according to their roles in the network security and relations between them are identified to constitute the network security model. This proposed model is based on organization based access control (OrBAC). However, the proposed model extend the OrBAC model to include not only access control policy but also some other administrative security policies like auditing policy. Besides, the proposed model enables matching of each rule of the high level security policy with the corresponding ones of the low level security policy. Through the second phase of the proposed framework, the high level security policy is mapped into the network security model. The second phase could be considered as a translation of the high level security policy into an intermediate model level. Finally, the intermediate model level is translated automatically into low level security mechanism. The paper illustrates the applicability of proposed approach through an application example.

Current cellular networks support video streaming over unicast or multicast. However, there exists a tradeoff between utilizing the two: i) unicast leads to higher network load, but lower energy consumption of mobile devices, and ii) multicast results in lower network load, but higher energy consumption. To make the best out of both, we propose to concurrently utilize unicast and multicast for minimizing the energy consumption of mobile devices and minimizing the load on cellular networks. Cellular networks support two multicast schemes: i) independent cell networks and ii) multi-cell single frequency networks, where multiple adjacent base stations operate on the same frequency. We first consider the less-complicated independent cell networks, and then extend our solution to single frequency networks for better performance. We formulate the resource allocation in hybrid multicast-unicast streaming systems as a binary integer programming problem. We describe optimal algorithms for the two multicast schemes. We then propose two efficient, heuristic, algorithms that run faster and provide close to optimal results. While our solution is general, for concreteness, we conduct detailed LTE packet-level simulations using OPNET. Our simulation results show the proposed algorithms i) scale to many more mobile devices than the state-of-the-art unicast-only approaches and ii) result in lower energy consumption than the latest multicast-only approaches. In addition, the algorithms designed for multi-cell single frequency networks outperform the algorithms designed for independent cell networks in all aspects, such as service ratio, spectral efficiency, energy saving, video quality, frame loss rate, initial buffering time, and number of re-buffering events.

The purpose of this paper is to increase the efficiency of functionality and reliability of Complex Recycling Technical Systems (CRTS) community, by improving the control quality of their life cycle. Automated Control System (ACS) on the basis of Neural Super-Network learning for forecasting damages and ensuring its information representation for learning was proposed. In the paper it was suggested an architecture and a method of learning of a neural super-network for forecasting the progress of CRTS community life cycle. The structure of the ACS life cycle of vehicles environment in the form of service "center" that service groups of "client", exploiting the same type of objects, was developed.

Abstract: This paper introduces theoretical results of research oriented on development object-oriented models of filter systems of attention. The diagrammatical language UML is used as a means of modeling of attentional systems. Two filteroriented hypothesis of ...

Abstract: This paper depicts theoretical results obtained in the line of projects related to constructing dialogue applications based on a formal cognitive model of a human-machine dialogue. One of the aims of the paper is to propose an appropriate model of question-...

The paper is an attempted to discuss one of the must important components in the architecture of personalized teaching systems-the testing system. One of the aims of the paper is to propose a definition of cognitive state, which can be used in designing personalized teaching systems.

This article presents results of a theoretical investigation of the application of the objectoriented Unified Modelling Language to a formal description of Neisser's cycle of perception. The article includes class diagrams, modelling the spatial structure of Neisser's cycle of perception and demonstrates how these formal descriptions can be applied to the area of modelling the problemindependent dialogue process. The basis of such applications is the assumption that the dialogue process in relation to either of the dialogue agents is similar to the process of routine perception of the environment in accordance with Neisser's understanding of perception.

During the last decade, many of the Intelligent Tutoring Systems (ITS) have been developed in different domains. ITS deliver important learning gains outside classroom environments. Expert systems have been extensively used to implement ITS in education. Frames are widely used as a knowledge representation for the expert systems. This paper proposes and discusses the construction of student's knowledge model in ITS using a frame-based expert system that can adapt to the students’ cognitive characteristics.

Computer-Aided Learning (CAL) tools could offer a better learning environment for computer science students. This paper presents a CAL tool that helps students understand the essential knowledge about networking design. The aim of the CAL tool is to simplify the process of network designing by using a user-friendly computer based program.

This paper aims at improving web server performance by establishing a middleware layer between web and database servers, which minimizes the overload on the database server. A middleware system has been developed as a service mainly to improve the performance. This system manages connection accesses in a way that would result in reducing the overload on the database server. In addition to the connection management, this system acts as an object-oriented model for best utilization of operating system resources. A web developer can use this Service Broker to improve web server performance.