Jaromír Hrad

Increasing the efficiency of the solar energy harvesting system is an urgent need in light of the climate changes we live in nowadays. The most significant data to be processed in the photovoltaic harvesters are the curve of solar radiation intensity to achieve the maximum benefits of the solar incident light. This processing contains complicated procedures, and the used algorithms are also high computational power-consuming which makes using special software and high potential hardware essential requirements. An explanation of the Minimum Energy Effect method is presented in this article. Our proposed algorithm uses this method to provide a simple and high-accuracy mathematical tool for generating a simple alternative curve instead of the complicated original nonlinear curve of solar radiation intensity. The produced curve is suitable for further operations, such as derivatives, integrals, or even simple addition/subtraction. Our algorithm provides a gradual procedure to find an op...

This paper deals with the issue of mobile device localization in the environment of buildings, which is suitable for use in healthcare or crisis management. The developed localization system is based on wireless Local Area Network (LAN) infrastructure (commonly referred to as Wi-Fi), evaluating signal strength from different access points, using the fingerprinting method for localization. The most serious problems consist in multipath signal propagation and the different sensitivities (calibration) of Wi-Fi adapters installed in different mobile devices. To solve these issues, an algorithm based on fuzzy logic is proposed to optimize the localization performance. The localization system consists of five elements, which are mobile applications for Android OS, a fuzzy derivation model, and a web surveillance environment for displaying the localization results. All of these elements use a database and shared storage on a virtualized server running Ubuntu. The developed system is implem...

The article offers an insight into specific features of mobile e-learning (m-learning) in terms of technical implementation, available platforms and their related problems, and evaluates the practical experience. It also summarizes reasons for introduction of mobile learning and analyzes available options for its technical implementation. Specific example is used to demonstrate practical use of m-learning courses - learning of English language for a defined group of recipients within an international Leonardo da Vinci pilot project “M-Learning for the Young People (Students) at Risk Groups (MLARG)”. Substantial part of the text is dedicated to the analysis of typical functions available in an m-learning system and to the discussion about its advantages, disadvantages and limitations, mainly in relation to the properties and features of conventional e-learning environments. The expected development of m-learning technologies is outlined in the context of modern learning method.

The present paper describes the causes and consequences of falling population in the Czech Republic and its impact on higher education institutions, forcing them to make some important changes. Several solutions are suggested with respect to maintaining the quality of education, employing modern methods and meeting actual students' needs and requirements.

The paper offers an insight into specific features of mobile e-learning (m-learning) and the alternative solutions for its implementation. Our practical experience with development of such system for the purposes of a pilot project is presented.

This paper describes a specific variant of very- high-speed digital subscriber line (VDSL) for access network in the Czech Republic under the terms of frequency bands released by Telefónica O2 CR. The spectral profiles are characterized by alternating bands for upstream and downstream directions when using frequency duplex. Further discussion deals with achievable bitrates under different conditions and the expected profiles that should be offered to subscribers. The resulting bitrates are calculated with respect to the length of the line with a copper core diameter of 0.4 mm and the number of disturbance sources for upstream and downstream directions. The analysis was performed using real distribution of subscriber line lengths in the Czech Republic. Higher penetration can be achieved with optical-metallic hybrid network. The optimal position of external node for very-high-speed digital subscriber line is deduced and proposed.

The present education in the area of data communications brings one substantial pedagogical dilemma. The given area is purely technical one. Its education inherently includes the contact with teachers during lectures, theoretical seminars, simulations of various processes, real measurements and analyses in a laboratory. Therefore the popular e-learning approaches cannot be fully utilized since that could possibly prevent students’ access

The paper describes a concept of a modern laboratory dedicated to education in the area of data communications. The laboratory is being built according to an analysis of pedagogical needs with respect to the recent trends, attempting to make the most of e-learning, access to virtual processes, flexible personal attendance and lectures on demand.

As we look at the environmental issues from the viewpoint of overall technical progress, we sho uld give, as soon as possible, the same priority to the issues of electromagnetic compatibility (EMC) in the context of teleinformatic systems development. Due to its interdisciplinary nature it requires specific appro ach within the educational system since it introduces substantial benefits for the developing information society, mainly in the areas of teleinformatic syst ems reliability and human health protection. The educa tional process must respect both the said interdisciplinar y nature and also the specific approach with respect to the individual engineering branches, including the possibilities of technical equipment for laboratory education. Also the hygienic aspects of EMC cannot be omitted. It is necessary to bring enlightenment to the wide public, but also to improve the approach to education and training of prospective specialists f or the industry.

The paper attempts to formulate the methodology for laboratory education of data transmission from the viewpoint of electromagnetic and spectral compatibility. The laboratory exercises a re based on several measurement workplaces, which share quite modest room - for example, in a laboratory of 50 square meters there are 6 of them, including those with wireless technologies (Wireless USB, GPS, WiFi, GPRS, UMTS, CDMA via GSM and BlueTooth). All these workplaces generate electromagnetic signals to thei r surroundings, and thus they represent sources of st rong disturbance to the neighboring ones. The disturbin g signals can negatively influence the measurement re sults (and often they do so); of course, this is undesira ble and unacceptable from the didactic perspective (since t he disturbed systems do not show the proper results th at, however, should be demonstrated). The paper focuses on looking for the optimum procedure and methodology to minimize the disturbances, so that the peda...