Article describes tile computing paradigm and introduces representatives of tile computing computer architectures with control and data driven computation models and describes data flow computing paradigm. Article introduces architecture of computer with data driven computation model based on principles of tile computing which is the modern approach to multi-core design of microprocessors, with basic principle of cores layout in bi-directional mesh of cores with interconnecting communication network. Architecture is proposed on the Department of Computers and Informatics, Faculty of Electrical Engineering and Informatics, Technical University of Kosice. Hardware implementation of computers prototype with use of Xilinx Spartan 3 AN development board with Spartan 3 AN FPGA chip is also described.

This paper deals with the optimization of data routing processes and with optimization of deployed quality of service mechanisms in computer networks. The paper addresses the problems related to requirement of monitoring and managing of network infrastructures with attention given to data routing mechanisms in network and often used QoS mechanisms. This paper also presents the concept of tool for automated network traffic management in order to network traffic optimization by identifying input curve α(t) and service curve β(t) with application of mechanisms for traffic shaping and adaptive elimination of aggressive data flows. Proposed methods are experimentaly verified and compared with conventional methods.

Quality of Service (QoS) in IP multimedia converged networks which provides different serving levels of different traffic flows is a crucial issue. The token bucket mechanism is one of core QoS concept whose well understanding is required and improve modelling and implementation techniques required in such multimedia networks. This paper describes and defines two basic network elements - a work conserving link and a token bucket. We define two different types of a token bucket and we show that both of them can be transformed into some work conserving link. Transformation means that the work conserving link allows input unit to pass if and only if the token bucket would allow input unit to pass.

We have witnessed a significant increase of the user requirements in the field of multimedia services. Therefore, service providers are forced to assure specific level of quality to earn the trust of theirs customers. QoE together with video quality have become essential terms in regard of designing any video-providing services. However, it was proved that current methods in the user-centered service design are inaccurate in considering resulting user experience and perceived quality of video streams. In this paper we are outlining actual state of art and future challenges in this particular problematic. All of which results in introducing of our new designed concept of QoE prediction model based on deep analysis and understanding of network behaving represented by sets of statistical data.

The Session Initiation Protocol (SIP) is a signalling protocol developed to set up, modify and tear down multimedia sessions such as voice and video calls, game sessions, messages exchange and the like over the Internet Protocol (IP). A few of protocols have been design for it. However, the SIP seems to be the most relevant protocol with the future. That’s all thanks to its manifold features. One of the most interesting is the Internet approach for programming new service. There are a couple of options that can be used for creating new SIP services. To create a service using the SIP, we should use SIP baseline protocol mechanisms. Another option is to define extensions to the baseline SIP protocol specification, defining new headers and new methods. Finally, dedicated programming tools for SIP can be used. Examples include a Call Processing Language – SIP CPL, Common Gateway Interface – SIP CGI, SIP Servlets, Java API for Integrated Networks - JAIN APIs. In this paper we present the usability of dedicated tools for creation and control of integrated services over SIP. We analyze different features of dedicated programming tools and provide their comparison.

This paper is review of many existing video surveillance systems. With the growing quantity of security video, it becomes vital that video surveillance system be able to support security personnel in monitoring and tracking activities. The aim of the surveillance applications is to detect, track and classify targets. In this paper is described object modelling, activity analysis and change detection. In this paper we will also describe a design of our video surveillance system.

This paper deals with two different approaches in programming sphere, and joins them in one entity through its practical part. One approach is context searching that is applied on the second approach, functional graphic library wxHaskell that is designed and implemented within Eclipse development environment through the plug-in extension. As searching object lies at the wxHaskell documentation, it is lexically analyzed, what forms a hashing table determined to searching for records.

The audiovisual and multimedia services are seen as important sources of data transmission within mobile networks these days. One of the limitations within the mobile networks is the low transmission bit rate which demands the reduction of the used video resolution and a high efficient video compression technique. Standard H.264/AVC, which is explained in this paper, is the newest codec of video compression, which provides a distinct improvement of quality in comparison with the previous video standards. Video stream transmission via wireless area results in data lost. It causes the emergence of the visual artefacts, and so the distinct fall of the picture quality. Since video stream transmission in real time is limited by transmission channel delay, it is not possible to transmit all faulty or lost packets. It is therefore inevitable to conceal these defects. In this paper, we analysed the error concealment algorithms, which are used in video transmission via wireless network, which are based on standard 802.11x. The simulation of the Improved Error Concealment Algorithm for Intra-frames was made in the computing environment Matlab, performed with standard model video-sequences.

Paper presents electric and magnetic field computation of 35 kV voltage level of transformer substation 35/10 kV using CDEGS software. Based on well known theoretical considerations of electric and magnetic fields, a realistic simulation model of transformer station 35/10 kV was develop. All calculations are made for horizontal plane with height of 1,5 m above the soil changing coordinates along x and y axes. The simulation results indicate that the values of electric and magnetic fields of the transformer station 35/10 kV are within the limits of regulations in Croatia. Furthermore, the simulation yields symmetric spatial distribution of the electric and magnetic fields on the observed plain, with maximal values at the points of geometric overlapping of conductor resultant fields.

This paper presents the analysis of Automatic Generation Control (AGC) of a two-area reheat thermal system under traditional scenario by considering the effect of Superconducting Magnetic Energy Storage (SMES) and Thyristor Controlled Phase Shifter (TCPS). Both these devices are modeled and an attempt has been made to incorporate these devices in the two area system thus improving the dynamic response of the system. The effect of these parameters on the system is demonstrated with the help of computer simulations. A systematic method has also been demonstrated for the modeling of these components in the system. Computer simulations reveal that due to the presence of SMES the dynamic performance of the system in terms of settling time, overshoot and peak time is greatly improved than that of TCPS.

This paper, presents a Direct Field-Oriented Control (DFOC) of doubly fed induction machine (DFIM) motor mode with a variable structure control based on a sliding mode control (SMC). Our aim is to make the speed and the flux control robust to parameter variations. The use of the nonlinear sliding mode method provides very good performance for motor operation and robustness of the control law despite the external perturbation. The results show that the sliding mode controller has better performance, and it is robust against external load variation. To validate the proposed method, the simulation has been carried out using MATLAB-SIMULINK software and the results are presented.

The paper focuses on the domain of user behaviour evaluation in the collaborative processes performed in a virtual user environment. Proposed historical projection of activities performed in such an environment provides several analytic perspectives materialised in form of different tools, but all of them are based on suitable visualization and extraction techniques. The differences are based on different analytical tasks to be supported by particular analytic tools. We will describe two of these analytic tools, but only one in more details because of our direct involvement in the design and implementation of this tool as project partner in the IST European project called KP-Lab. The main technological output of this project is represented by KP-Lab System as an original platform for support of collaborative working and learning practices based on knowledge creation metaphor. The first analytic approach is based on interactive visualisation of available historical data based on user requirements in simple and user friendly graphical formats as graphs or charts. The second analytic approach provides historical retrospective of performed collaborative processes based on timeline form visualisation of performed events with different selection a patterns’ search capabilities. These two approaches can be used instead of often used manual methods of user behaviour evaluation e.g. in a learning course. Manual evaluation is much more time consuming and tedious for teachers or researchers from several reasons: necessary collection of all materials from students, laborious analysis of their communication channels etc.; e.g. in this case it is difficult to identify the real involvement of each student. Suitable visualisation of automatically collected data with the possibility to define constraints based on users’needs provides easier approach, mainly in the case of large students’ groups. In our paper we will describe our motivation, related works, briefly the first analytical approach and the second one in more details as an important output of our research group.

Attribute oriented programming allows programmers to extend source code elements semantics by adding decorative comments called annotations. Annotations can be then processed by tools and frameworks during compile or run time. With wide usage of such tools and frameworks, annotation creators define many constraints on how these should be used. Constraints are usually expressed informally in source code comments or external documentation. Correct annotation usage is validated lately during deploy or run time. This paper presents a tool that checks annotation constraints at compile time using a Prolog like constraint language. The tool uses an embedded database to store program elements and a simple constraint to SQL compiler. Query results are then asserted against existing annotations to check their validity. The tool can be seamlessly integrated with existing IDEs.

Different electronic services offered in e-banking, e-commerce, e-government, e-manufacturing, e-learning, etc. are becoming to be a part of everyday life for people everywhere. A communication portal has become universal solution in all cases from common communication between persons or information and data interchange up to e-business. For the creation of quality portal for information interchange of sensitive character, it is necessary to know standards dedicated to this purpose. The main requirement for these platforms is document and data interchange, what presumes usage of well-known and attested standards. Using the portal also imposes trust of users. One way of building the trust in a platform is usage of accepted standards. In this paper we concentrate on two groups of standards – standards for technological data and information exchange and standards for interchange security.

The replacement of the disappearing incandescent lamps will be realized at a significant scale by compact fluorescent lamps (CFLs). Light regulation is a popular feature that is easily provided by incandescent lamps using a simple electronic equipment, the dimmer. Dimming can be achieved by (dimmable) CFL lamps as well, however this is done in a completely different way than in case of the former. This different method relates to different electromagnetic emission characteristics and electromagnetic compatibility (EMC).