Alarm systems represent a combination of the various modern engineering solutions (electrical, mechanical, hydraulic, etc.) with the primary goal to protect human lives, living and working environment and material properties. Detectors are basic and common components of these systems. There are many different kinds of detectors which usage depends on system solutions, prices and other technical properties of system application. Different types of non-typical lines can be used as detectors in alarm systems, such as coaxial cables or special constructed electrical lines. The change of some parameters of cables, such as capacity, impedance, resistance or similar, according to temperature, pressure, torsion or other disturbances, can be used for detection of intruder or fire. This work presents experimental results obtained on three different types of coaxial cables: RF 75-3-1, RF 75-4-5 and RF 75-7-9 in order to show changes of capacity as a consequence of heating due to growth of surrounding temperature, and consequently, possible application of cables as fire detector. Before an experiment, a simulation of fire in laboratory 113 in Electrotechnical school Nikola Tesla in Nis was made in FDS (Fire dynamic simulator) software to show the possible spreading of fire, and consequently, to find optimal location for coaxial cables as fire detectors.

The appearance of fire in objects with lot of humans inside represents very possible real situation that could be very danger and could cause destructive consequences on human lives and material properties. Very important influence in fire prediction, fire protection, human and material properties safety could be a fire simulation in object. This simulation could give many useful information of possible fire propagation; possible and existed evacuation routes; possible and exited placing of fire, smoke, temperature conditions in object and many other information of crucial importance for human lives and material properties, such as the best places for sensors position, optimal number of sensors, projection of possible evacuation routes etc. There are many different programs for fire simulation. This paper presents complete fire simulation in Electrotechnical school Nikola Tesla in Niš in FDS.

Object evacuation is one of the most important, the most responsible and the most complex tasks for human safety in objects generally. This is especially important for objects with lot oh humans, such as health facilities, high residential objects, hotels, schools, etc. This is still an open and ongoing problem which can be confirmed by many injured people who were not evacuated in the disasters. This paper has written to show the possible evacuation situation and calculate minimal time for evacuation in case of Hotel Radon in Niška Banja, as one specific health facility with hardly moving and immobile patients.

During the past several years, the use of Internet has become a daily part of life for many people worldwide for many reasons. The development of new devices, the low cost of Internet services, and the great capabilities of the Internet, make Internet alluring for many adults and children to use it for many hours almost daily. However, there are some negative consequences of the Internet, especially for school-age children. One of these consequences is the so-called "Internet addiction". Many studies indicate that the Internet is becoming the primary and only means of communication, the principal and the sole medium when it comes to the life of a school-age child. There is a neglect of sports activities, socializing, live chat, going out in nature etc. Some aspects of the life are slowly being replaced by the virtual. The happiness that a child should feel when solving problems or during sport competitions, is being substituted by the happiness experienced while playing video games. The main responsibility lies within the family and school teachers, who must jointly and constantly supervise and direct children to other aspects of life, nature, socializing, sports etc. Of course, the use of the Internet should not be criticized or disputed, and it should be viewed as something that makes life easier and intends to serve the users. This review summarizes the results of previous research on the misuse of the Internet by school-age children in different countries of the world and at the Electrotechnical school "Nikola Tesla" in Niš, with the aim of proposing appropriate preventive measures to ensure their proper development and guidance.

The appliance of many new technologies brought many benefits to modern society. Modern life is, generally, easier, faster and risen at the much higher level. The speed of modern technology use is such that it is almost impossible to have a complete view-only the benefits of modern technologies are noted. Mobile phones, laptops, tablets, drones, Internet, Facebook, Skype, 5 G network and many other examples of new technology application have lots of benefits. But, have these technologies started to be used with taking into account the potential by bad consequences that they can have? Can all potential by bad effects and consequences of modern technology use be predicted, analyzed and prevented? The main goal of this paper was to confirm and present that the increase of digital violence caused by usage of modern technologies and to show factors that are included in children protection from digital violence in Serbia. Research presented in this paper were realized by the author of the paper as longitudinal research for several years in several elementary and secondary schools in Nib, so as some research from world prove that increased use of modern technologies inevitably leads to digital violence, primarily among school age children. The paper also presents the role of different instruments in digital violence prevention and sanction in Serbia. Digital violence indeed presents a bad consequence of modern technologies and must be treated in appropriate pedagogical and legal way.

The appearance of fire in objects, especially in objects with lot of humans inside represents very possible real situation that could be very danger and could cause destructive consequences on human lives and material properties. Very important task in fire protection, human and material properties safety could be a proper adoption of fire detectors and theirs disposition in object. The right type of fire detectors, with theirs disposition and density has to provide right time reaction, with minimal occurrence of false alarms and acceptable price. There are many different factors for fire detectors selection. On the other hand, there are several standards for fire detectors disposition. This facts show that good projected fire protection sys­tem must satisfied a lot of different and important tasks. This paper presents representation of fire detectors, their selection according to the different factors, theirs disposition in object according to proper standards and simula­tion in PyroSim software as an evidence for noted facts.