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Nowadays, wireless optical systems are very popular because they offer a a lot of advantages including high speed transmission, high security levels, and low maintenance costs. One of these wireless optical systems is Free Space Optics (FSO). However, their primary drawback relates to the type of transmission medium used. Atmospheric channel is chosen to be the transmission medium for FSO systems. The resulting attenuation relates with all inhomogeneities that occur in the atmosphere. Concentration of water particles represents inhomogeneities which increase the levels of attenuation. Weather conditions are characterized by speciffc concentration of these particles. Visibility is one of the most crucial parameters for FSO communication. It is very important to monitor this parameter in order to switch between primary optical line and backup secondary Radio Frequency (RF) line. The focus of this paper is to analyze and evaluate visibility measurement in FSO system deployed in TUKE (Technical University of Kosice) campus. The measurement of different weather parameters for this system is triggered on TUKE. The Switching method is based on monitoring visibility as the primary parameter. Different measurement approaches provide different processing speeds. Faster and more accurate switching ensures stable system without disruption.

This article deals with magnetic nano-fluids, which are the part of transformer oil ITO 100 and their behavior is influenced by a permanent magnetic field. We performed an IRC analysis in the time domain on the three different samples. Measurements were made before and after radiation of an electromagnetic field. The main objective was to examine changes in the properties of the samples due to the influence of the electromagnetic field. The measurements depend on the orientation of the external magnetic field. This behavior occurs especially during the structuring of the nanoparticles in the sample exposed to the magnetic field. These processes change the polarization of the liquid because the nanoparticles concentration is contained in the fluid.

Nowadays we are living in the ages of innovations. The expansions of communication systems is unbelievable. Many of devices recent are based on database and cloud systems. They need to be connected with other devices and services provider. Well known types of transmission are radio frequency (RF) and optical systems. They use different access for communication. In case of RF systems is need in/out device proposed to receiving/sending of signals. Now are available the many of types of antennas. They are divided by purpose, shape, material, value of radiated power, gain and price. For each purpose is appropriate different type of antenna. The low cost type of antenna is microstrip patch antenna. They are represented by different shapes and materials. Microstrip patch antenna contains the layer of substrate placed between two conduct layers. Parameters of antenna could be affected by change of relative permittivity of substrate. Nowadays are available many of high frequency materials with low value of relative permittivity. The point of this paper is comparison of two types of microstrip patch antennas witch different shapes of radiation patch. [ABSTRACT FROM AUTHOR]

This article deals with determining the value of maximum permissible current with consideration of ambient conditions. Each ambient conditions and their influence on the value of current ampacity for ACSR conductor 350/59 in comparison with ampacity given by calculation accordance the standard EN 50341 are described in this article. Static ambient conditions are given in this standard and change in the ambient conditions was neglected in calculation of the resulting value. The aim of this article is to refer the influence of the change of ambient environment and ambient conditions to the maximum permissible current. [ABSTRACT FROM AUTHOR]

Light and lighting, with this need we encounter in everyday life. During the day, it fills this need sunlight but there are cases when it is necessary to illuminate interior spaces during the day. In another situation we face at night when it is necessary to illuminate indoor or outdoor spaces artificially. This need for interior lighting fills the artificial lighting and discipline that deals with the lighting is called lighting technique. Well as other industries also lighting, respectively lighting technology goes through the development of new technologies. This paper deals with lighting, specifically analyzing the effectiveness of relamping in terms of investment costs. The first part of the article is devoted to the basic theoretical knowledge of the field of lighting technology. Subsequently are characterized further light sources. The last part of the article is the analysis and compares costs for different light sources and from the perspective of the average and useful life. [ABSTRACT FROM AUTHOR]

Today's wireless time brings some comfort, but on the other hand the impact of electromagnetic fields is serious threat to people. Many studies dealt with the effects of electromagnetic fields on living organisms, but the results are not completely clear. General and scientific public is increasingly focused on the impact of electromagnetic fields on living organisms. This is closely related limit values for parameters characterizing exposure to electromagnetic fields, depending on the frequency range, as defined by the Ministry of Health Decree 534/2007 Z.z. on the details and requirements for sources of electromagnetic radiation and exposure limits citizens to electromagnetic radiation in the environment. This contribution therefore focuses on mapping the electric and magnetic fields in the environment. The environment was selected area with a higher concentration of people in Prešov. The mapping was performed in two frequency ranges from 1 MHz to 1 GHz and 1 GHz to 2 GHz. [ABSTRACT FROM AUTHOR]

The design and analysis of various types of antennas is necessary to consider the impact of electromagnetic radiation transmitter and receiver module before the antenna is constructed. Electromagnetic radiation of antennas and its impact on the environment is the subject of many studies. The programming environment FEKO (FEldberechnung bei Körpern mit beliebiger Oberflache) is translates as "Calculation of electromagnetic field objects of any shape" already offered by its name the space for the design and analysis of the antennas of any shape. First parts of this article discusses environment FEKO. Another section is devoted to design and analyze a dipole antenna as the primary representative of the antennas in terms of electromagnetic radiation, which was the basis for the simulation. [ABSTRACT FROM AUTHOR]

At present, as users' requirements for bandwidth and transmission media capacity increase, development of new technologies needs to meet the requirements. Optical fibers have offered solutions in this area, but such implementation of connections in some areas is costly. An effective solution of this problem is application of FSO (Free Space Optics) technology. FSO technology makes it possible to achieve transmission rates comparable with optical fibers at a distance of up to 10km. However, this technology has other drawbacks. One of them is the sensitivity to weather changes, in particular sensitivity to presence of fog. In this case, the transmitted optical beam interacts with water particles in atmosphere, which significantly affects quality of received optical signal. In an extreme case, there may be a connection failure that is undesirable. One solution is to deploy a backup line. In our case, we have designed a radio link in the unlicensed 2.46GHz band using microstrip antenna. [ABSTRACT FROM AUTHOR]

Gyroscopes are widely used in various applications for decades, but the idea to construct a gyroscopic system, able to exploit the properties of the gyroscope and also monitor the status information arose later. The expansion of the optical fiber technology also touch the subject, with the development of such interferometer measuring means to explore a variety of non-optical parameters led to the idea of the application of this knowledge to the already known systems. This optical system has been constructed on a fundamental principle of the gyroscope, but we can’t talk about pure gyroscope, because there is an optical interferometer that uses its features. So it was named as fiber optic gyroscopes. In this article we describe fiber optic gyro system, design and testing experimental measurements with this gyroscope system. [ABSTRACT FROM AUTHOR]

The improvement of LED components in parameters such as efficiency, thermal resistance or operating life enables to use these excellent properties in applications such as spot lights, street light, automotive headlamps etc. However, the use of these new technologies is closely associated with the essential requirements related to electromagnetic compatibility. The paper is focused on the electromagnetic compatibility of a prototype of LED street light with various drivers. As a basis for analysing of the compliance with EMC standards the requirements for the harmonic content of input line current and power line conducted emissions was used. The results obtained from experiments pointed to the fact that some of the voltage drivers are incompatible with requirements for the harmonic content of input line current. The problem is caused mainly by two factors: improper circuit design of the LED driver, or bad design of the LED driver with respect to the rated load. [ABSTRACT FROM AUTHOR]