Vojnotehnicki glasnik / Military Technical Courier

23-41

Authors: Inđić Dejan R., Luković Zoran T., Mučibabić Spasoje D.

Chemical accidents are inevitable in modern technological development and they cause a number of effects on people, property and the environment. The nuclear-biological-chemical (NBC) services as well as specialized units of the Army of Serbia perform particular tasks in the elimination of the consequences of chemical accidents. This paper presents a modeling of the effects of chemical accidents and one possible method for the selection of NBC services engaged in the elimination of the consequences of chemical accidents, using the method of analytic hierarchy processes.

58-73

Authors: Tadić Marin M., Čitaković Nada M.

The sol-gel method was successfully utilized for the synthesis of the highly concentrated α-Fe2O3/SiO2 nanocomposite containing 45 wt% of hematite. TEM micrograph showed that spherical particles of 10 nm average size were evenly dissolved in glassy silica matrix. Both DC magnetization and AC susceptibility measurements indicated superparamagnetic behaviour of the system with the blocking temperature TB ≈ 65 K. Magnetization vs. field data at 300 K was successfully fitted to a weighted Langevin's curve for superparamagnetic system and the particle size obtained from this fit was in excellent agreement with the TEM results. Several features evinced in the magnetic data pointed to the presence of non-negligible magnetic interaction between hematite nanoparticles: the weak field dependence of the magnetization as a function of temperature, narrowing of the hysteresis loop at low applied field below TB, and high value of TB for hematite nanoparticles of 10 nm in size. On the other hand, features like continuous increase of the ZFC magnetization with decreasing temperature and the absence of a plateau or a peak in the FC branch showed that no strong magnetic interactions were present in the system. The AC susceptibility study showed that the Vogel-Fulcher model for singledomain inter-acting particles was applicable, while the empirical parameters C1 = 0,055 and C2 = 0,57 that lie between values for strongly interacting systems and non-interacting systems obtained have pointed to the presence of the interactions of intermediate strength. On the basis of the above listed results, we can conclude that the system under consideration consists of interacting single-domain hematite nanoparticles with magnetic properties that are located between weakly and strongly interacting systems.

89-111

Authors: Pavlović Rade M., Petrović Vladimir S.

We propose a novel method to fuse true colour images with monochromatic non-visible range images that seeks to encode important structural information from monochromatic images efficiently but also preserve the natural appearance of the available true chromacity information. We utilise the β colour opponency channel of the lαβ colour as the domain to fuse information from the monochromatic input into the colour input by the way of robust grayscale fusion. This is followed by an effective gradient structure visualisation step that enhances the visibility of monochromatic information in the final colour fused image. Images fused using this method preserve their natural appearance and chromacity better than conventional methods while at the same time clearly encode structural information from the monochormatic input. This is demonstrated on a number of well-known true colour fusion examples and confirmed by the results of subjective trials on the data from several colour fusion scenarios.

130-140

Authors: Grečihin Leonid Ivanovič

The paper presents the aerodynamics of a wing of a closed oval ellipsoidal shape, designed with the use of the molecular-kinetic theory. The positive and negative characteristics of aircraft - drones with an oval wing are described. The theoretical calculations have been experimentally checked.

167-193

Authors: Janković Bojan Ž., Janković Marija M.

The differential conversion curves of the non-isothermal NiO reduction process by hydrogen are fitted by the Weibull (non-isothermal) probability density function (Wpdf), in a wide range of the degree of conversion (α = 0.06 - 0.96). It was established that the Weibull distribution parameters (β and η) show the different dependences on the heating rate of the system (vh) (shape parameter (β) - linear form and scale parameter (η) - exponential form). Model independent values of the apparent activation energy were calculated using the Friedman's isoconversional method. It was found that the calculated apparent activation energy depends on the degree of conversion, α, and it shows a constant value in the range of the degree of conversion 0.20 ≤ α ≤ 0.60 (Ea = 90.8 kJ mol- 1). Knowing the Weibull distribution function of reaction times, it is possible to determine the density distribution function of apparent activation energies at different heating rates. It was established that the changes of the symmetry of density distribution functions may be an indication for deviations from the simple crystallization kinetics as expressed by the Johnson-Mehl-Avrami (JMA) model, and this behaviour is probably due to a more complex transformation process such as a process described by the two-parameter autocatalytic Šesták-Berggren model.

199-211

Authors: Pašić Muhamed H., Ružić Dragana R.

This paper describes the modernization by installing frequency converters, their features and benefits as well as the disadvantages of the existing solutions and the advantages of the upgraded status. The existing state was such that the motors were switched on through the contactor and were always working at full capacity. In the new solution, one motor will be switched on through frequency converters, thus working with a particular intensity, depending on the need. This will bring savings in power consumption as well as in the maintenance.

26-47

Authors: Mrdak Mihailo R.

This paper analyzes the influence of the plasma spray distance on the microstructure and the mechanical properties of the Co32Ni21Cr8Al0.5Y coatings deposited with the vacuum plasma spraying (VPS) procedure. The microstructure and the mechanical properties of the plasma spray coatings were determined by the interaction of the Ar/H2 plasma ions with the powder particles when the transfer of the speed and temperature of ions on the powder particles occurs. The effect of interaction directly depends on the time of the interaction between ions and powder particles, which is defined by the plasma spraying distance. The powder is deposited by the plasma gun F4 at three substrate distances: 270, 295 and 320 mm. The coating with the best structural and mechanical properties was tested on the oxidation in a furnace for heat treatment without protective atmosphere at 1100°C in a period of 240 hours. The morphology of the powder particles was examined on the SEM. The microstructure of the layers in the deposited condition was tested by light microscopy. The coating with the best mechanical properties was electrolytically etched with 10% oxalic acid solution H2C2O4x2H2O. The analysis of the microstructure of the etched coating was performed by light microscopy and on the SEM, before and after testing the coating on oxidation. The microstructural analysis of the deposited layers was performed in accordance with the 'Pratt-Whitney' standard. The mechanical properties of the layers were assessed through the examination of microhardness by the HV0.3 method and through bond strength tensile testing.

70-79

Authors: Stopić Srećko R., Kozma Robert Đ., Pavlov Tanja J.

In the light of contemporary forms of migration and in the context of globalisation and rapid development of technology and transportation, diaspora is increasingly viewed through the transnational prism. Instead of forcedly scattered countrymen, who dream of returning to their homeland and have difficulties with the integration in the reception country, diaspora is seen as a link that connects worlds, the country of origin and the receiving country, thus enabling migration to be used for development of the community and society on the whole. Instead of return, the emphasis is on the circular exchange and transnational mobility. In this way countries of Southeast Europe are trying to transform the 'brain drain', which was particularly prominent in the 1990s, into 'brain circulation' and 'brain gain'. In Serbia, 1990s migration was triggered by saving lives, primarily from the painful and bloody civil wars waged in the former Yugoslavia, international isolation and NATO bombing, as well as the difficult economic situation. In that period, the particularly massive departure was that of young and educated people with the generally accepted slogan 'to graduate, and then to emigrate'. However, migration of educated people and professionals, often motivated by career development and professional advancement abroad, has continued after 2000. Many young people are enabled to go abroad with the help of foreign scholarship foundations aiming at assisting development in Serbia, such as the Alexander von Humboldt Foundation AvH, German Academic Research Service DAAD, Mummert Foundation, etc. Therefore, the main objective of this paper is to determine the possibility for connection between professionals from diaspora and young students and engineers in Serbia, in order to facilitate the transfer of knowledge and their mobility and thus prevent the irreversible loss for the country. In addition to theoretical considerations of the possibility to improve cooperation with the diaspora, the paper analyses an example of successful cooperation between professionals in the metallurgical industry from Germany and professionals from Serbia, initiated by a representative of the professional diaspora. Finally, recommendations are made as to how to apply the lessons learned from the literature and practice for the development of sustainable cooperation among the professional diaspora and youth and professionals in Serbia.

121-137

Authors: Epler Igor J.

For any modern army it is very important to continuously maintain a high degree of operational (combat) readiness (availability) in order to maximize the effectiveness of the use of technical systems. Since determination and prediction of technical states and failures of technical systems in engineering, especially in armament, are difficult due to the impossibility of continuous condition monitoring with appropriate measuring equipment there is a need for a maintenance model that would be most helpful in taking timely action maintenance. In this paper, the subject of research is a model of maintenance of the M-84 tank weapoons systems. Introduction. The M-84 tank is one of the most promising technical systems in the Serbian Army. Its use and modifications are foreseen in the next ten years. The M-84 is characterized by good tactical and technical characteristics. It has a powerful 125 mm cannon, coupled 7.62 mm machine gun and 12.7 mm anti-aircraft machine gun. The M-84 tank has an automatic battery charger and a fire control system. The fire control system enables fast target tracking and stabilization of the cannon barrel, which is a prerequisite for timely and favorable effect on the target. There are certain ambiguities in the existing model of maintenance of tank weapons.

161-179

Authors: Rutić Srđan Z.

The article presents the application of modern educational technology in the training for the management of accidents with chemical hazards. It describes the 'HeSPRO' software package created to integrate the functions of evaluation and prediction of the effects of hazardous substances both in chemical accidents and during the use of highly toxic substances. The assessment of the software package application was carried out based on hypothetical models. The chemical hazard assessment was carried out through the analysis of the obtained results. It was concluded that the software package provides optimal conditions for effective evaluation and prediction of the situation in chemical accidents with hazardous materials.

198-212

Authors: Marković Srđan S., Stojanović Danijel V., Bakrač Saša T., Zorić Marija M.

In modern society, people are surrounded by many industrial facilities where technological accidents may occur due to breakdown, fire or explosion, endangering people residing in the immediate vicinity of the plant as well as those residing at a greater distance. In addition to the direct threat to humans, there are also indirect effects of technical and technological accidents which may be much more dangerous than direct effects. These indirect effects are manifested primarily from degraded and polluted environment, they are long term and often lead to illness and death of many people. The paper attempts to present all negative consequences of technical and technological accidents on the elements of a human security regarding the approach to the interpretation of human security in terms of sustainable development.

233-255

Authors: Mrdak Veselin L., Petrović Veljko P., Luković Branka R.

The paper wants to emphasize the importance of contemporary strategic management approachs in the defense system. Displays the work of American author Leslie Lewis and C. Robert Roll 'Strategy-totasks: a methodology for resource allocation and management'. It were used by parts of the discussion above, in order to describe the strategy-to-tasks methodology for planning, programming and budgeting system (PPBS). In developed Western countries adopted some elements of strategic management to determine and monitor the execution of strategic plans in the defense system. This trend is spreading to other countries as a result of the necessity of obeying certain methodological and technological achievements. The uncritical acceptance of a strategic management approach can cause great confusion and problems, and the terminology and scientific explanation for this trend is of great importance.

271-275

Authors: Gaćeša Nebojša N.

The article does not contain abstract.

26-50

Authors: Demić Miroslav D.

Dynamic simulation, based on modeling, has a significant role during the process of vehicle development. It is especially important in the first stages of vehicle design, when relevant vehicle parameters are to be defined. Shock absorbers as executive parts of vehicle semiactive suspension systems suffer thermal loads, which may result in damage and degradation of their characteristics. Therefore, this paper shows an attempt to analyze converting of mechanical work into heat by using the dynamic simulation method.

63-71

Authors: Staretu Ionel A., Ionescu Marius A.

Pyrotechnic robots are service robots used to reduce the time for intervention of pyrotechnic troops and to diminish the danger for the operators. Pyrotechnic robots are used to inspect dangerous areas or/and to remove and to distroy explosive or suspicious devices/objects. These robots can be used to make corridors through mined battle fields, for manipulation and neutralization of unexploded ammunition, for inspection of vehicles, trains, airplanes and buildings. For these robots, a good functional activity is determined with regard to work space dimensions, robotic arm kinematics and gripper characteristics. The paper shows the structural, kinematic, static synthesis and analysis as well as the design and functional simulation of the robotic arm and the grippers attached on the pyrotechnic robot designed by the authors

99-112

Authors: Stopić Srećko R.

The synthesis of metallic nanoparticles from the precursor solution of salts using the ultrasonic spray pyrolysis method was considered in this work. During the control of process parameters (surface tension and density, the concentration of solution, residence time of aerosol in the reactor, presence of additives, gas flow rate, decomposition temperature of aerosol, type of precursor and working atmosphere) it is possible to guide the process in order to obtain powders with such a morphology which satisfies more complex requirements for the desired properties of advanced engineering materials. Significant advance in the improvement of powder characteristics (lower particles sizes, better spheroidity, higher surface area) was obtained by the application of the ultrasonic generator for the preparation of aerosols. Ultrasonic spray pyrolysis is performed by the action of a powerful source of ultrasound on the corresponding precursor solution forming the aerosol with a constant droplet size, which depends on the characteristics of liquid and the frequency of ultrasound. The produced aerosols were transported into the hot reactor, which enables the reaction to occur in a very small volume of a particle and formation of nanosized powder. Spherical, nanosized particles of metals (Cu, Ag, Au, Co) were produced with new and improved physical and chemical characteristics at the IME, RWTH Aachen University. The high costs associated with small quantities of produced nanosized particles represent a limitation of the USP-method. Therefore, scale up of the ultrasonic spray pyrolysis was performed as a final target in the synthesis of nanosized powder.

122-140

Authors: Kitanović Ranđel N., Šušteršič Vanja M.

Quality of life on Earth in the future will largely depend on the amount of safe water. As the most fundamental source of life, water is relentlessly consumed and polluted. To halt this trend, many countries are taking extensive measures and investing substantial resources in order to stop the contamination of water and return at least tolerably good water quality to nature. The goal of water purification is to obtain clean water with the sewage sludge as a by-product. Clean water is returned to nature, and further treatment of sludge may be subject to other procedures. The conclusion of this paper is simple. The procedure with purified water is easily achievable, purified water is discharged into rivers, lakes and seas, but the problem of further treatment of sludge remains. This paper presents the basic methods of wastewater treatment and procedures for processing the products from contaminated water. The paper can serve as a basis for further elaboration.

159-172

Authors: Petrović Dragana N., Đedović Branko N., Petrović Nikola Č.

The cost-benefit-benefit analysis is a comprehensive analysis of benefits and cost-benefits of a project which that project brings to the project owner and to the society as a whole (including investors). The selection of the best investment alternative is realized on the basis of financial and economic analyses, as two integral parts of the cost-benefit-benefit analysis. The first of these was dealt by the same group of authors in the article 'Application of the cost-benefit-benefit analysis in the evaluation and selection of public projects (financial aspect)', published in the previous issue of the Military Technical Courier. The subject of this paper is the processing of an economic analysis as a logical extension of the previous work. Therefore, the number of labels included in the table of the financial analysis content (1-5) supplements (in the chronological order) label tables that belong to the economic analysis (6-8). The application of the economic analysis is achieved by a certain, quite complex procedure, and ends by establishing the basic criteria (indicators) of the economic (social) cost-benefit of the project, such as a net present value of cash flows and a cost-benefit-benefit ratio. The project is economically viable and socially justified for implementation if the first criterion is greater than zero, and the second criterion is greater than one. In the case of alternative choices, the project with the highest present value of cash flows and the highest value of the cost-benefit- benefit ratio will be selected. This paper processes all the issues regarding a gradual realization of the economic analysis in order to determine the economic viability of the project.

197-216

Authors: Kostadinović Dragan S.

The paper describes the restrictions on the joint transportation of dangerous goods in the same vehicle, with a focus on dangerous goods of Class 1 (explosive materials and objects with explosive materials), which are, considering their purpose, typical of the Serbian Army. It also describes the conditions under which the transport of dangerous goods does not apply specific requirements that must be met during the transport of dangerous goods, as well as a way of labellng vehicles for ordnance transportation.

231-247

Authors: Suša Vladimir B., Bajčetić Jovan B.

This paper deals with management system requirements in telecommunications. A TMN (Telecommunication Management Network) is necessary to be well designed and constantly upgraded. The ETOM (Enhanced Telecommunication Operation Map) framework, defined by the ITU-T Recommendation M.3050, is used to describe various processes that occur in the network for monitoring and control of military telecommunications systems. Their definition is an essential precondition for introducing management applications that would manage all of the processes in their end-to-end structure. Telecommunication net works are categorized in accordance withg their functions. A set of relevant network processes important for supervision and management is explained for each described subsystem. This defining represents a prerequisite for the management application configuration which aims to automate management functions and services.

268-279

Authors: Batinić Milanka S.

In order to have the best execution of required job tasks, the best task performer should be chosen. The problem of selection of job candidates has been present for long and it was mainly based on empirical estimates and feelings. Multicriteria analysis methods allow a more objective approach to the selection of job candidates. One of these methods is the method of analytical hierarchy process (AHP), which, besides the selection, provides the sensitivity analysis of solutions. This paper considers the criteria for manager selection and analyzes the sensitivity of the obtained solutions with the assumed set of alternatives.

23-36

Authors: Stanković Momir R., Manojlović Stojadin M., Naumović Milica B.

A method for the identification of the DC state space model parameters based on the minimization of the error function using the least squares method is described in this paper. The algorithm is practically applied in the laboratory environment on an industrial DC motor. The verification of the results was performed by comparing the characteristic signals of real and modeled systems. The results show that the quality of the identification is satisfactory.

55-83

Authors: Šunjevarić Milan M., Veletić Mladen B., Todorović Branislav M.

Mobile station localization in mobile networks started with simple methods (e.g. Cell-ID method) which required only slight modifications of network infrastructures. Principally, it was about network localization by which a localization service became available to all types of mobile phones. Due to low precision, the initiated development of more sophisticated methods has not been finished yet. Among the advanced location-based methods are those based on the measurement of location parameters in the time domain. In this paper the general consideration of radio location methods in 3G (UMTS) radio networks is presented. The use of time based measurement methods was analyzed in detail. Due to the limited article length, the use of other locating methods in 3G networks (based on power measurements, on radio direction measurement, and on cells identification - Cell ID and global positioning system - GPS) are not described.

105-122

Authors: Rudolf Rebeka T., Ferčec Janko J.

The fixed orthodontic appliance consists of brackets that are bonded to the teeth. When the wire is engaged in the slot of the brackets, it generates forces for orthodontic tooth movement. The change in periodontal blood supply provides a biological response which leads to remodelling of the alveolar bone and the orthodontic tooth movement. Many variables influencing orthodontic treatment cannot be controlled fully, such as growth and tissue response to appliances. However, the force placed on the tooth should be a controllable variable, and a careful study of the physics underlying clinical applications can help in reducing undesirable side effects. The properties of orthodontic wires such as: strength, stiffness, elasticity and spring-back define their clinical usefulness. The ideal orthodontic wire should exhibit the following properties: large spring-back, low stiffness, good formability, high stored energy, biocompatibility and environmental stability, low surface friction, and the capability of being welded or soldered to auxiliaries. The ideal arch wire has not been introduced yet. Once the wire is activated or bent, it is the unloading or deactivating forces that produce the orthodontic tooth movement. For these reasons, it is necessary to know the force level caused by each individual wire used in orthodontic treatment. Finally, the purpose of this paper is a presentation of force measurements which are generated by different super-elasticity NiTi wires.

140-158

Authors: Petrović Dragana N., Đedović Branko N., Petrović Nikola Č.

The cost-benefit analysis is a very useful tool for the evaluation and selection of public projects, especially those with a life expectancy of 30 or more years, such as: building hospitals, irrigation canals, bridges, tunnels, development and production of new funds and new weapons and military equipment (WME), etc. The analysis can also be applied in the private sector for the evaluation of projects which are in one part financed by state funds or through loans when enterpeneurs or companies doe not show interest or do not have sufficient funds for the realization of projects (for opening schools, theaters, etc). The cost-benefit analysis provides information for government agencies and commercial banks about the profitability of investments, without which they cannot make a decision of financial support for the project realization. The selection of the best investment alternatives is realized on the basis of financial and economic analyses as two integral parts of the cost-benefit analysis. The content of this paper is the financial analysis that examines the financial viability of the project only from the standpoint of the sponsor and financier. In one of the next issues of the journal, we will also process the economic analysis as well as a complete analysis of the effectiveness of the project.

182-199

Authors: Ristić Slavica S., Polić-Radovanović Suzana R., Jegdić Bore V.

Infrared (IR) thermography, as a diagnostic technique, is used to find anomalies in the thermal signature of the Military museum building in Belgrade, to identify irregularities or deficiencies, such as wet materials, voids, or missing insulation and to inspect energy efficiency of the museum building and microclimatic indoor conditions. It is very important to perform preventative maintenance and stop undesirable environment influences that induce structural damage, modification of materials and agglomeration of pollutants and microorganisms on the cultural heritage artifacts, stored in the museum depot or exhibited in the galleries. The main causes for corrosion in historical buildings and museum artifacts are moisture and changeable temperature conditions. This paper deals with the results obtained in the application of IR thermography in determination of these conditions in the Military museum building, where very important metal artifacts are exhibited and deposed. The results show poor thermal insulation, wet walls and, generally, low energy efficiency.

218-241

Authors: Radonjić Vesna M., Todosijević Andrijana N., Petrović Milica R., Stojanović Mirjana D., Kostić-Ljubisavljević Aleksandra K.

Accounting of telecommunication services is closely related to the functions of authentication and authorization. These functions are usually considered together and implemented within the same server using a common protocol. The most renowned protocols for authentication, authorization and accounting are the RADIUS and Diameter protocols. AAA functions and related protocols. In this chapter, the accounting management architecture developed by IETF is presented. It includes the interaction between network elements, accounting servers and billing and charging servers. Accounting data can be used for management, planning and charging users as well as other (specific) purposes. Authentication is the process of confirming a user's digital identity, usually through some type of identifiers and related data. Authorization determines whether a particular entity is authorized to perform an activity. Basic Functions of the RADIUS Protocol. The RADIUS architecture is based on a client-server model. It uses UDP on the transport layer. Transactions between the client and the server are authenticated, which is achieved by using a common secret key that is never sent through the network. Given the limited resources available to network devices, RADIUS facilitates and centralizes charging end users, provides some protection against active attacks by unauthorized users and it has great support from different network equipment vendors. Although RADIUS is a widely accepted protocol for the mechanisms of authentication, authorization and accounting, it has certain shortcomings that may be caused by the protocol itself or by its poor implementation. Architecture and Operation of the Diameter Protocol Diameter is a scalable protocol designed by the IETF working group in order to eliminate shortcomings and functional limitations of the RADIUS protocol and eventually to replace it in the near future.

272-290

Authors: Inđić Dejan R., Krsmanović Zoran M., Terzić Miroslav R.

This paper presents the assessment of the operational - geographic features of the Drina-Velika Morava strategic direction. Due to the scope of the article, a variant of the assessment of the strategic direction is presented through its socio-geographic factors, while the mathematical-geographical and physical-geographic factors, as well as the operating lines of action are not discussed. Within the socio-geographic factors, the characteristics of the population, economy and communication networks are considered. The geographic area of the direction is nationally compact and provides war mobilization of units with no particular strain. The transportation network is not fully developed which makes combat operations difficult to attackers and facilitates them for the defenders. There are significant technical and technological potentials in the direction of the zone, but they are not evenly distributed. After the consideration of the complex socio - geographical factors, it is concluded that the shown strategic direction enables, without any special restrictions, a successful execution of combat operations in the long run.

309-313

Authors: Gaćeša Nebojša N.

The article does not contain abstract.

21-45

Authors: Šunjevarić Milan M., Popović Milorad L., Todorović Branislav M.

The paper presents the results of the research into the opportunities for the integration of mobile broadcast TV networks and cellular 3G networks. We analyzed trends in mobile television services as well as previous studies that aim at finding optimal ways to integrate different types of networks. This paper analyzes the existing mobile television technology, with a special emphasis on the DVB-H technology. We analyzed the conditions, reasons and opportunities for the integration of DVB-H and 3G UMTS (Universal Mobile Telecommunications System), and the conclusions of these analyzes are supported with the results in practice. Based on these studies, a conclusion on the feasibility of the realization of DVBH/ UMTS hybrid networks is brought.

58-68

Authors: Batinić Vojislav J.

Internal dynamic forces and displacements along the anticipated degrees of freedom in planetary gear trains are a consequence of coupled teeth elastic deformations, vibrations of train parts and changes in gear geometries due to tooth wear and cutting errors. This paper considers the influence of time-varying mesh stiffness on possible displacements and forces in tooth contacts. The timevarying mesh stiffness functions were useful as nonlinear coefficients of gear mesh stiffness in a system of differential equations for an equivalent gear train model in the determination of the nature of displacements and internal dynamic forces. The results of the numerical analysis of differential equations describing dynamic behaviour are time- varying functions of displacements of system points and dynamic forces in tooth meshes of the sun-planet and ring-planet meshes.

89-100

Authors: Stopić Srećko R.

Critical materials represent mostly metals having a big importance for the future of the economy in the European countries. It is very difficult to replace these critical metals by other metals. Because of their wide application, the demand for these metals is increased, but the production cannot follow their growing consumption. Rare earth elements (REE) belong to critical materials. They include 17 elements, very similar in terms of their chemical and physical properties due to their mineralogical structure (the best-known are lanthanum and thorium, which is radioactive). REE are divided into elements with a lower atomic mass and elements with a higher atomic mass. Heavier metals show a significantly lower presence in the upper earth crust. In 2010, the share of the REE production in China in the global production amounted to 97%, constituting a near-monopoly in the world market. In different studies, the term 'Strategic' is often used instead 'of 'critical' materials. The materials for military application are called 'Strategic' (nickel). In comparison to strategic metals, critical materials have a big importance for the national economies of European countries (platinum group of metals, rare earth elements, cobalt). The European Commission prepared a strategic development plan for critical materials in the next twenty years.

123-135

Authors: Markagić Milorad S.

The article gives an overview of the possibilities of digitized mobile (portable) devices, and the methods of analyzing data from them. Although the emphasis is placed on the forensic investigation of mobile phones, other media for digital processing, transmission and storage of information are covered as well. A special emphasis is put on the software tools in carrying out the digital data acquisition, with the aim of informing the reader on the methods of data protection, sources where they can be found and how they can be misused for criminal purposes.

146-161

Authors: Čabarkapa Obrad T., Petrović Dalibor P., Dunjić Marina S.

Inventions are the results of creative work protected by patents or petty patents, provided that the patent was filed. Inventions are the kinds of innovations of a technical character because they offer solutions for technical problems and they can relate to any area of technology. In its essence, each invention has specific technical characteristics (precisely defined through patents claims) that are sought to be protected. Patent protection is the right which admits the holder to achieve the goal of economic exploitation of the invention. In order to get the invention patent protection, an invention should be patentable, i. e. it should meet the following requirements: the existence of the invention, novelty, inventive step and industrial applicability of the invention. In general, the study of these conditions should start from the national legislation in the area of patent protection which specifies what cannot be considered as an invention and what cannot be protected by a patent or petty patent. The examination of patentability is done in a particular stage of the examination procedure by experts in the technical field which the invention relates to. If all the required conditions are met, it is said that the invention is patentable and that the patent protection is possible.

178-195

Authors: Epler Igor J.

The existing models of technical systems maintenance management provide required reliability and availability of systems, preferably with as little cost as possible. New concepts, increasingly applied in all areas of life, are based on risk. Such an approach is possible and desirable in the field of theory and engineering of maintenance of technical systems and military technical systems. In this paper, the conceptual definitions of technical systems maintenance, maintenance management models and strategies are given, followed by an overview of strategies and models of maintenance of technical systems, their shematic views and mutual comparisons and trends in the management of maintenance of technical systems, the application of which could lead to savings in the maintenance of both technical and military technical systems.

210-225

Authors: Inđić Dejan R., Terzić Miroslav R., Ivanković Negovan D.

Earthquakes, floods, nuclear and chemical accidents as well as air, soil and water pollution indicate the increasing presence of accidents caused by intensive development and often uncontrolled application of technological development. There is raising awareness how to be better prepared, how to ensure greater compatibility and operation activities and measures for the prevention of accidents and how to make changes in social and technological developments for the benefit of both the nature and future generations. The paper describes the use of various information systems (IS) in the management of environmental risks and gives a proposal to develop a unique IS in Serbia.

242-259

Authors: Samčović Andreja B.

The evolution of cloud computing over the past few years is potentially one of major advances in the history of computing and telecommunications. Although there are many benefits of adopting cloud computing, there are also some significant barriers to adoption, security issues being the most important of them. This paper introduces the concept of cloud computing; looks at relevant technologies in cloud computing; takes into account cloud deployment models and some military applications. Additionally, Security-as-a-Service is specially considered because of its importance in the military applications. Cloud computing (CC) is such a combination of computer hardware, software, online services and expertise networked by high-speed Internet connections. What is more, cloud computing is a model of using computing resources (servers, disks, operating systems and applications) where these resources are rented and not bought. The consequence of this approach is that users pay only as many resources as they actually have used (pay-as-you-go), so they do not need to take care about either hardware procurement and its installation, or software (operating system and applications) maintenance. Most of the cloud computing architecture used nowadays includes public cloud computing networks for providing services through the Internet, such as Google Search, Microsoft Hotmail or Google Adsense. Large service providers, together with typical pioneers in adopting new technologies such as financial services and pharmaceutical companies, also apply the architecture of CC in the implementation of private cloud networks protected by firewalls. This mode of use is still in its early stages and is expected to achieve further growth in the corporate database virtualization technologies that are now being introduced. The framework used to describe cloud computing services is known as the acronym SPI (Software Platform Infrastructure) and marks the three major services provided through the clouds: Softwareas- a-Service (SaaS), Platform-as-a-Service (PaaS) and Infrastructureas- a-Service (IaaS). Traditional methods of purchasing software involve software upgrading onto hardware with paying license fees (which is capital expenditure). The user is also able to enter into any contract for maintenance and to get security patches and other services for software support at a certain price. The compatibility of operating systems and the installation of patches is the responsibility of the user. Being a simplified representation of complex, interconnected devices and connections that form the Internet, the term 'cloud' is a metaphor for the Internet. Public and private (external and internal) clouds are the parts of the Internet and are defined (or, rather, they differ) based on the connections formed by institutions. Similar to SaaS, the Security-as-a-Service cloud service model is delivered to customers on a subscription basis. In addition, SaaS is also applied in the Security-as-a-Service. There are three incentives for the development of Security-as-a-Service. The earliest driver is spam which is now more than a decade old. Another driver for the development of Securityas- a-Service is a service for managing safety (MSS, Managed Security Services). The impetus for the use of MSS was (and still is) the same as for the use of CC: reduced cost compared to home solutions due to the use of shared resources. Also, the MSS model breaks the informal but powerful barrier of displacement (outsourcing) of the parts of the information security program of an institution. In this case, displacement implies control devices outside the institution (off-premises). It should be noted that, although outsourcing IT security is often an option, initially it can only be used in the relocation of the facility (outsourcing on-premises), ie. to be moved into another room within the same building, as opposed to the relocation outside the building. It should be taken into account that cloud computing changes the existing business models. From the perspective of information security, the biggest change brought by cloud computing is collecting shared resources of multiple users at a centralized location. This change results in a shift of confidence limits; exactly where these limits are is not clear yet. Confidence limits are different for each model of SPI (Software-as-a-Service, Platformas- a-Service and Infrastructure-as-a-Service), even when limits vary within each of these models depending on the cloud service provider.