Vojnotehnicki glasnik / Military Technical Courier

5-16

Authors: Mrdak Mihailo R.

The paper presents the results of the examination of atmospheric plasma spraying of APS-NiCr/Al coatings. Composite NiCr/Al powders, composed of NiCr particles coated with fine Al particles, enable an exothermic reaction during the deposition process. The exothermic reaction of these metals results in the formation of selfbonding NiCrAl coatings with a unique combination of properties. For the purpose of obtaining excellent structural and mechanical properties, the deposition parameters were optimized. In this study, three groups of NiCrAl coating samples with different powder deposition rate were made to get deposits of greater strength and toughness. In the first group of samples, the deposition rate was 50g/min, in the second group the powder deposition rate was 40 g/ min. while in the third group it was 30 g/min. The assessment of the properties of deposits was made by the HV0.3 microhardness testing method and the bond strength was examined by tensile strength testing. The metallographic evaluation of the structure was done by optical microscopy The verified coatings were applied for the protection and revitalization of parts exposed to oxidation at elevated temperatures. Introduction Plasma spraying is widely used in many industries to improve performance of components. This process has found wide applications in many industries such as aviation, petrol chemistry or automotive industry. Plasma spraying is one of the most efficient thermal processes. A jet of plasma particles has a wide range of both temperature and rate. A typical plasma temperature range is from 8700 to 12000°C and the rate range is from 80 to 400ms-1. Composite NiCr/Al powder consists of NiCr alloy particles (nuclei) coated with fine Al particles. Deposited coatings are better than NiCr and Ni/Al-type coatings. They are resistant to oxidation, hot corrosion, sudden changes in temperature, abrasion, erosion, and they react well to mechanical damage. Mechanical strength of bonding remains adequate up to a working temperature of 980°C. For designing NiCrAl coatings with the best structural mechanical properties, three groups of samples with different powder deposition rates were made. The aim of this work was to improve the repair of the sections of turbo jet engines rejected due to wear-based oxidation, hot corrosion and other damage mechanisms. Experiment details and materials The coated AMDRY 960 powder of the Sulzer METCO company was used in the experiment. The NiCr/Al powder was developed for the production of coatings which are often used separately as a protection of the base metal from oxidation and hot corrosion at high temperatures or in a combination with ceramic coatings as a middle layer. Powder deposition was performed at atmospheric pressure with a mixture of Ar-He plasma gases and the power supply of 40KW. The study examined three groups of samples to get deposits of high toughness. The powder deposition rate in the first group of samples was 50g/min with a carrier gas flow of 7 l/min, the second group of samples had a powder deposition rate of 40 g min. with a carrier gas flow of 6 l/min. while the third group of samples had 30 g/min. of the deposition rate with a carrier gas flow of 5 l/min. Testing microhardness, bond strength and microstructure The testing and characterization of the coating layers were made in accordance with the TURBOMECA standard. Microhardness was measured along the lamellar layers with the Vickers test with 300 g load (HV 0.3). The microhardness test samples and the samples for microstructure analysis were made of Č.4171 (X15Cr13 EN10027) steel in the thermally raw state with the dimensions of 70x20x1.5 m. Testing the coating/supstrate interface strength was done by the tensile test. The specimens for tensile bond strength testing were made in accordance with the TURBOMEC standard, out of Č.4171 (X15Cr13 EN10027) steel in the raw thermal state with 25x50 mm in diameter. The microstructure of the layers and the quality of the coating/supstrate interface was analyzed using an optical microscope with a magnification of 400X. Results and discussion The obtained results show that the microhardness values for layers in all three groups of specimens were over 170HV0.3.The highest microhardness values (from 346 to 357 HV0.3) occurred in the layers deposited with the powder deposition rate of 30 g/min. The values of the bond strength confirm that there is good adhesion between the coating and the substrate; the cohesion strength of the lamellae in coating layers is good as well. The destruction in all coatings was of an adhesive type along the coating/supstrate interface. The coating qualitative analysis showed that the uniformity of layers on the substrate was obtained without the segment separation of layers from the surface of the substrate. The coating quantitative analysis showed that the structure of the substrate is a solid solution of chromium and aluminum in nickel light gray color. On the light gray lamelar boundaries, there are dark gray oxide (NiO and Cr2O3) lamellae and black α-Al2O3 lamellae as a result of air penetration into the plasma jet and micro pores. The existing pores are black and account for less than 8%. Conclusion Atmospheric plasma spraying (APS) was used for three NiCrAl coatings with three different powder deposition rates (30.40 and 50 g/min). Their mechanical properties were investigated and the coating microstructure was analyzed, resulting in satisfactory mechanical properties. The following conclusions were drawn: The highest values of micro hardness of 346-357HV0.3 were found in the layers deposited with the powder deposition rate of 30 g/min. With the increase of the powder deposition rate, the microhardness of layers decreases. The highest values of the bond strength of 72MP were found in the layers deposited with the powder deposition rate of 30 g/min. The coating properties were confirmed in the exploitation of functional parts.

37-62

Authors: Andrejić Marko D., Sokolović Vlada S., Milenkov Marjan A.

In order to be efficient and effective, logistic services, as a part of the defence system, has to be designed and organized in a high-quality way. They must have a long-term development concept with built-in organizational aspects, clearly expressed focuses and priorities in the functioning and well-defined indicators of quality performance. In order to reach the required operational capabilities and the desired state of the logistics, it is necessary to achieve a philosophical, intellectual, doctrinal, technical and operational unity within the logistic system and then with the other subsystems of defense, in accordance with the needs of practice, the requirements of modern times and trends. The starting point for achieving a high degree of unity within the Army logistics is the definition of the concept of the development of logistic services with a built-in organizational aspect, as an intellectual conceptual sketch containing the guidelines and recommendations for intellectual thinking, development and operational activities and contributing to the gradual formation of a unified understanding of the logistic system of defense. When considering the directions of the development of logistics services, certain analogy will be applied as in other successful, complex multilevel, organizational and economic systems. The existence of long-term concepts of development, with a built-in organizational aspect, is something that will be asked from competent control and decision-makers. In this paper, certain aspects and segments of the development of the logistics process will be discussed with a high degree of generalization, by relying on authors' experience and research as well as on available sources of knowledge. The aforementioned approach allows for a greater generalalisation of the given views; on the other hand, it can get in strength (the depth and accuracy) if validly operationalised in each logistic service, in each particular element or case. Defense as a function of the state Each and every state has an undisputable right on individual and collective defense. Defense is an important state function for the realization of which the government (legislative, executive and judicial) is responsible. The defense of the state is the general necessity, right and obligation of all defense and security subjects. No one can be exempt from the efforts necessary for successful defense; therefore, all resources (regardless of property) within the state's territory, under certain conditions, become defensive potential and the defense function of the country, according to their nature and needs of the country's defense. Defense logistics Besides the well-trained personnel, the logistic system of a country comprises appropriate legislation, appropriate production and services, equipment, raw materials, energy sources, infrastructure and all other necessary support for the realization of corresponding production, service, social, educational, cultural, defence, etc. programs aiming at the increase of the defence and economic potential of a country. Logistic support system According to the general theory of systems, each system consists of a set of parts that form a functional unit, types of connection and levels of intensity of relationships between parts and the principles (rules) on the basis of which these components are connected into a unity. A logistic support system includes: staff in administrative and executive bodies of logistics, material resources and logistic organs of units; location where components of logistic support are developed, logistic facilities and installations, legal acts and military literature and documentation in the field of logistics support. Global tendencies in the development and operational logistics in the modern system of defense Given that the logistics is a major manufacturer, supplier and distributor of material resources and a large consumer of financial resources, it has to be the area of management attention, both civil and military ones, and of permanent control in the phase of planning, organizing and implementation of logistic activities. This control is primarily related to financial and material operations, quality products and services, logistics solutions and priorities. It is in the area of control that the most of potential disagreement occurs. Understanding the nature and the degree of logistical control systems (skills, good reasoning ability and balanced reasoning) that management should realize is important for achieving the expected efficiency and effectiveness. Aspects and elements of the concept of the logistic service development In defining the concept of the development of logistic services it is necessary to bear in mind the mission of logistic services as a part of the defense system, aims which logistic services should achieve, results to be obtained and tasks to be executed. The missions of individual subsystems supported by logistic services and their functioning in peace, crisis, mobilization and war should be also taken into account. The concept of the development of logistic services should be directed to the logistic system and its interior as well as the elements of the system, but should also respect the environment of the system and its effect on the operational and functional capabilities of logistic services, both existing and considered ones. Conclusion There is a significant necessity and possibility for logistics and logistic services to be developed integrally on the scientific basis both as a skill (practice) and a scientific discipline (theory), in relation with other defence disciplines and subsystems. The necessity to improve logistic aspects of planning and logistic support planning is stressed in particular. It is important to intensify efforts in raising the level of the logistic culture of the users of logistic services. Under the conditions such as insufficient funding, continuous pressures for the reduction of army personnel along with the requests to increase Army operational capability and intensify its involvement in integration processes, it is possible to find a solution in high-quality personnel, equipment, information systems and science-based work organization. However, there are no fast, cheap and efficient solutions in the development and functioning of logistics. A prerequisite for effective and efficient functioning of logistic bodies are normative regulations, staff qualifications, development of adequate infrastructure and logistic infrastructure, a clear definition of needs and procurement of material and financial resources for mission realization. Logistic staff needs to be improved as a whole, taking into account the specific structure of individual personnel members: officers, NCOs, civilians, professional soldiers, soldiers in military service, soldiers under contract, personnel in active reserves. Career officers should be initially as well as subsequently trained at the Military Academy, because that staff proved to be reliable and of high quality. However, since it takes time, a possibility should be considered to occasionally receive a number of high-quality graduate engineers and economists from outside the military and then train them at the Military Academy. Staff for specific logistic services (SnSl, VtSl, GrSl) should only be obtained from the non-military and then trained within the organized defense system. Specialized training of soldiers, NCOs and civilians has to be again under the stronger jurisdiction of logistics in order to meet all specific logistic requirements. Building logistic infrastructure and equipping logistic units with modern means is an important financial issue for even more economically and technically developed countries. However, this should not and cannot be a reason for abandoning designed goals, as logistic activities and tasks are based on technological processes and procedures that must be adequately supported both financially and technically. In addition to working on the modernization of logistics in all areas (technical, technological, organizational), considerable effort should be put into the development and improvement of logistic information systems, into quantification of logistic capabilities, and then into quantification of needs for logistic support in order to shorten the response time.

134-154

Authors: Jovanović Boriša Ž.

Digital multimedia content is becoming widely used and increasingly exchanged over computer network and public channels (satelite, wireless networks, Internet, etc.) which is unsecured transmission media for ex changing that kind of information. Mechanisms made to encrypt image and video data are becoming more and more significant. Traditional cryptographic techniques can guarantee a high level of security but at the cost of expensive implementation and important transmission delays. These shortcomings can be exceeded using selective encryption algorithms. Introduction In traditional image and video content protection schemes, called fully layered, the whole content is first compressed. Then, the compressed bitstream is entirely encrypted using a standard cipher (DES - Data Encryption Algorithm, IDEA - International Data Encryption Algorithm, AES - Advanced Encryption Algorithm etc.). The specific characteristics of this kind of data, high-transmission rate with limited bandwidth, make standard encryption algorithms inadequate. Another limitation of traditional systems consists of altering the whole bitstream syntax which may disable some codec functionalities on the delivery site coder and decoder on the receiving site. Selective encryption is a new trend in image and video content protection. As its name says, it consists of encrypting only a subset of the data. The aim of selective encryption is to reduce the amount of data to encrypt while preserving a sufficient level of security. Theoretical foundation of selective encryption The first theoretical foundation of selective encryption was given indirectly by Claude Elwood Shannon in his work about communication theory of secrecy systems. It is well known that statistics for image and video data differ much from classical text data. Indeed, image and video data are strongly correlated and have strong spatial/temporal redundancy. Evaluation criteria for selective encryption algorithm performance evaluation We need to define a set of evaluation criteria that will help evaluating and comparing selective encryption algorithms. - Tunability - Visual degradation - Cryptographic security - Encryption ratio - Compression friendliness - Format compliance - Error tolerance Classification of selective encryption algorithms One possible classification of selective encryption algorithms is relative to when encryption is performed with respect to compression. This classification is adequate since it has intrinsic consequences on selective encryption algorithms behavior. We consider three classes of algorithms as follows: - Precompression - Incompression - Postcompression Overview of selective encryption algorithms In accordance with their precedently defined classification, selective encryption algorithms were compared, briefly described with advantages and disadvantages and their quality was assessed. Applications Selective encryption mechanisms became more and more important and can be applied in many different areas. Some potential application areas of this mechanism are: - Monitoring encrypted content - PDAs (PDA - Personal Digital Assistant), mobile phones, and other mobile terminals - Multiple encryptions - Transcodability/scalability of encrypted content Conclusion As we can see through foregoing analysis, we can notice that tunability, cryptographic security and error tolerance are the main unsatisfied criteria. Selective encryption algorithms based on static encryption parameters do not allow tunability. Tunability is a desirable property especially for content protection systems targeting different applications with different requirements in terms of security or visual degradation and different devices with different capabilities in terms of memory, computational power, or display capabilities. It is therefore appreciated to design a tunable selective encryption algorithm with dynamic encryption parameters.

172-179

Authors: Jelenković Natalija B.

In this article, mathematics is dealt with as a science necessary for the design, development and implementation of certain military-technical achievements such as many electronic devices, smart missiles, miniature antennas, camouflage military clothing and other military equipment. Some areas of applied, discrete and continuous mathematics are underlined in particular. Application of mathematics The importance of mathematics for military-technical achievements is reflected in the fact that mathematics allowed the existence and development of military disciplines such as: fortifications, military statistics, military economics, cryptography, military psychology, air force, military-technical and military information science. There are also many applications using mathematical models and linear programming. Mathematics is thus necessary and indispensable as a tool, a way of expression and communication, as well as the basic creation of further progress. This article reveals the connection of mathematics and certain military areas that are important for the development of the armed forces and war materiel. The application of mathematics in military- technical achievements is entailed in the connection of mathematics with military disciplines. Information technology - Basic concepts Some identified problems occurring in military purposes are mentioned through some basic concepts and benefits related to information technology. Comparative description and listing of characteristic traits resulting in the noticed and given advantages and disadvantages highlighted the creation of information technologies, first by using conventional programs and programming and then by using artificial intelligence and expert systems.

5-31

Authors: Bakić Selena P., Paligorić Anastas L.

For more than a century researchers in many countries have been engaged in research and development of electromagnetic (EM) guns in order to launch projectiles with very high speed. In published sources many papers are related to theoretical considerations of certain phenomena of electrically driven projectiles and hardware solutions for electrical devices and components required for projectile launching. The works related to the philosophy of combat use, the concept of solutions and possibilities of application of such weapon systems are, however, less available to the public. The intention of the authors of this paper is to point out the basic problems of designing such weapon systems, and to give the readers the information on the basis of which they can assess whether it is possible, when and on what kind of platform for the EM gun to be approved for the operational use.

47-64

Authors: Tadić Marin M., Čitaković Nada M.

In this work the results of an investigation on hematite (α-Fe2O3) nanoparticles magnetic properties, which show superparamagnetic behavior i. e. superparamagnetism, have been presented. Hematite nanoparticles behavior and nanoparticles size influence on magnetic properties have been presented. Hematite nanoparticles properties have been compared with a high cristallinity hematite sample.

78-87

Authors: Terzić Miroslav R.

One approach to the evaluation of the effectiveness of a system for acoustic source localization and identification has been shown in this article. The system for acoustic source localization and identification has been presented as a model of mass servicing system. The states of the system as well as its features have been described while the formula for service probability determination has been derived as a criterion for effectiveness evaluation. The introductory part of the article describes the system for acoustic source localization and identification and shows a model for quantity estimation of the function of technical system effectiveness E (t). The system effectiveness represents a probability of system initiation as well as a probability of its successful mission accomplishment on the basis of designed capabilities within the given time period and operational conditions. The basic characteristics of the Boomerang system for acoustic source localization and identification show the system elements and its designed capability to detect, analyse and distribute acoustic source location data. The analytical model for the evaluation of the effectiveness of the Boomerang system for acoustic source localization and identification shows that 'n' stations for acoustic source localization can exchange information with each other using the network link. The system conditions are described and the expression for the determination of service probability as a criterion for system effectiveness evaluation is derived. The evaluation of the effectiveness of the Boomerang system for acoustic source localization and identification is presented with a formula for determining mass servicing system probability from the Matlab 6.5R13 program. The following graphs have been obtained: - correlation between mass servicing probability and processing acoustic signal intensity for m=1,2,3,i; - correlation between mass servicing probability and the number of stations for acoustic source localization and identification. The obtained graphs help in the optimization of the system for acoustic source localization and identification. The conclusion gives some guidelines in applying this analysis and achieving optimal resources employment in combat environment.

105-124

Authors: Trifković Dragan R., Obradović Aleksandar M.

The procedure of replacing the elements of a complex torsional vibration system of ship diesel engine propulsion with simplified equivalent ones with the same dynamic characteristics is shown in this work. The given procedure comprises the methods for the determination of equivalent lengths, stifnesses and moments of inertia based on the equality between kinetic and potential energy of real and equivalent elements of the system. Additionally, the exciting moments which excite forced torsional vibrations of the considered system are analysed.

146-161

Authors: Karović Samed M., Komazec Nenad M.

Building of the Integrated Management System (IMS) represents a necessity, because it incorporates the existing management systems of an organization according to the ISO standards (The International Organization for Standardization), whose aim is to satisfy managerial and organizational practical work.. The conditions are thus established and the key elements in the field of quality, ecology, security, economy, reliability, compatibility, efficacity and effectiveness are provided.

5-25

Authors: Holclajtner Marko S., Jeremić Olivera M., Milinović Momčilo P.

This paper presents a procedure for an efficient simulation of MLRS barrage fire as well as of the effects of rocket parameters. The rocket behavior will be analyzed with reference to an ideal trajectory generated by an ideal rocket. The quality of MLRS fire is expressed through dispersion of impact points in the target area thus representing precision and accuracy. This work assumes absolutely correct accuracy and concentrates primarily on the effects of precision i. e. on the dispersion of rockets. Other types of effects on rocket dispersion, such as those of atmosphere, launching, etc. are neglected. The ammunition effects on the trajectory dispersion will be thus identified. The dispersion in the target area will be correlated with the dispersion of trajectory points at the end of the active (rocket motor burn out) phase.

43-52

Authors: Mrdak Mihailo R.

In this paper, the microstructural, mechanical and tribological properties of WCCoNiCrBSi thermal spray coatings, applied to repair the cylinders of helicopter nasal feet, were analyzed. The process used for coating deposition on steel substrate was the Atmospheric Plasma Spraying (APS).The plasma spray process is a procedure widely used for applying coatings with increased resistance to wear. The combination of WCCo and NiCrBSi powders produced coatings for the protection of metal parts exposed to wear abrasion, erosion and cavitation to 540°C. The WCCoNiCrBSi 50/50% powder is specially developed for the production of coatings of high cohesion and adhesive strength. The coatings are very dense, hard and smooth. Microstructures present in the layers are tungsten carbides and chromium layers that increase resistance to wear and abrasion. Powder is deposited on the substrate rugged with Al2O3. The substrates were heated at temperatures up to 200°C. Powder deposition was performed with the optimal deposition parameters The microstructure and micro hardness of the coating layer was investigated on the cross section of samples using the Pratt & Whitney standard. Micro hardness was tested using the Vickers scale with a load of 300g. The microstructure of the layers was investigated on an optical microscope (OM) with a magnification of 400X. Testing of bond strength between coatings and substrates was performed at room temperature with the speed of twitch of 1mm/60sec. The structure is multi-layered and layers are dense and homogeneous. In the WCCo layers there are dark WC phase particles. The NiCrBSi alloy layers contain fine precipitates of white nickel borida. The WCCo layers have micro hardness values ranging from 1097 - 1390 HV0,3. The tribological evaluation of the coating was performed using a pin - on ring tribometer. Lubricate sliding wear tests were carried out at room temperature according to the ASTM G77 standard. The coated blocks were tested on a hardened and tempered steel ring. A constant load of 400 N and a constant speed of 0,5 m/s were applied for a total distance of 3000 m. The values of micro hardness were also measured in the NiCrBSi layers in a narrow range of 823-930 HV0,3 The values indicate that the layers are homogeneous and thick. The coating bond strength is 59N/mm. The value is high because of the warming substrate. The dynamic coefficient of friction has a value of μ = 0,1 to 0,11. The mass loss was small and on average it amounted to Δmb = 0,11 mg. The results of tribology tests showed good reproducibility of the dynamic coefficient of friction. The coating can be reliably applied to surfaces exposed to wear during operation. The advantage of this coating application is in a significant prolongation of service life of parts, together with reduced operating and maintenance costs.

71-89

Authors: Ivković Dejan S.

In all analyses the MUSIC method has given better results than the FFT method. The MUSIC method proved to be better at estimation precision as well as at resolving two adjacent Doppler frequencies. On the basis of the obtained results, the designed estimator of radial velocity can be said to estimate Doppler frequency in the reflected signal from a moving target precisely, and, consequently, the target velocity. It is thus possible to improve the performances of the current radar as far as a precise estimation of velocity of detected moving targets is concerned.

108-126

Authors: Bondžulić Boban P., Petrović Vladimir S.

This paper presents a robust multisensor background extraction and update scheme intended for use in target detection applications. The method uses a number of well known concepts in detection to provide a basic classification of the scene into moving and stationary objects and an iterative procedure to update the background model and deal with transient (slow) changes in illumination conditions. A new fusion- based confidence framework uses the information from multiple registered views of the scene obtained by different sensors in order to update the background model only in areas where there are no moving objects. It was shown on a number of representative multisensor sequences that the proposed method obtains a more complete and robust representation of the background than any estimate based on the individual sensors. Finally, a relatively simple computational architecture of the proposed system makes it ideal for demanding real time multisensor detection applications.

150-164

Authors: Pešić Predrag J.

The purpose of explaining the model of resource management with the signal reserve, the process diagram and the SIPOC model of the supply chain explained was to present the opportunity for applying modern approach of Technical logistic in the management of the supply chains in military organizations. The described model allows efficient management of resources and material stocks by monitoring the changes in resource levels for individual stocks, groups of materials and the overall reserves. By applying ABC and XYZ analysis with the logistic Controlling the AX class materials (large annual demands and with well planned expenditures) could be well managed at short notice, in extreme cases even without any stocks by applying the 'just-in-sequence' strategy.

179-187

Authors: Radojčić Steva M.

The main conclusion is that only when the measures of accuracy and those of reliability are taken together, they form a sufficient basis for the assessment and comparison of the quality of geodetic networks.

5-12

Authors: Jovanović Danko M.

The paper discusses the notions of risk and risk management in specific conditions of the production of weapons and military equipment (MWE). The main characteristics of explosive materials, the most frequent risk sources in the production of MWE, have been analyzed as well as the phases in the risk management process and the risk management methods. Introduction Risk is nowadays considered as a serious economical, public and political issue. Risk management enables identification and control of uncertainty varieties in order to avoid or reduce them by offering alternative activity routes to decision-makers. The production and application of modern WME involves handling hazardous materials and imposes needs for safety measures. Particularities of the WME production Explosive materials for military goods cause the greatest risks in production and charging as well as in storage and use. They consist of explosives, gunpowder, rocket propellants (solid and liquid), liquid oxidizers of rocket propellants and pyrotechnic mixtures. Reducing risks in production to an acceptable level The key of successful risk management is a clear definition of a risk assessing domain s well as the identification and characterization of potential threats. The risk management process consists of the following phases: risk identification, risk analysis, risk assessment, procedures in risk occurrences and the risk control of required measures. Conclusion The management of each company has a key role in risk management, reducing risks to acceptable levels in cooperation with government and specialized institutions.

33-61

Authors: Andrejić Marko D., Milenkov Marjan A., Sokolović Vlada S.

A logistics automated information system should be developed as a part of a unified automated information system (JAIS). In order to develop a logistics automated information system and to apply it successfully in operational use, it is necessary to follow the JAIS global development concept and rely more on teamwork of IT experts and specialists in real logistics systems. An important condition for the development of a high-quality logistics information system is to define information needs for particular objects treated by a logistics information system. The task of such a system is to provide: permanent insight into the logistics system, pointing to the necessary and possible measures for improvement, better real system planning and management activities, personnel information about the state of the real system, pointing to the directions of further system development. A logistics information system should be developed taking also into account compatibility with future allies and partners. Defense systems were among the first to accept the challenge (because they were forced to) to introduce information technology in their management system and, with the help of innovations in this area, to increase the performance effectiveness under the conditions of environment dynamic changes. Information technology development mostly followed development of large military projects aimed at solving management or technology issues within military industry complex and management in the most technologically developed defense systems. These science and defense practice efforts resulted in many new methods and techniques such as the method of system analysis and information system design, methods of operational research and simulation, pattern recognition, expert systems for individual processes in management, as well as those for information retrieval and their implementation in decision making. Over time, partial innovations reached a high level of synthesis, leading to new management systems able to function in most complex task conditions. Mastering the procedure of creating autonomous partial information systems-where the operational research methods helped to optimally apply some of their particular values - has led to the creation of integrated automated information systems for management support. Our recent defense theory and practice have not concentrated enough on logistics information systems in professional journals, neither from the organizational nor from the technological point of view. Experiences gained from operational practice and knowledge acquired by visiting foreign armies, practical needs as well as modern times demands and current trends in the development of defense systems pointed out that it is necessary to pay more attention to this logistics segment in military journals. Logistics information systems cannot be researched, developed and introduced into operational practice (applied) without knowing the structure of high-quality information systems in general. High-quality information systems for supporting the logistic aspects of decision-making and logistics dealing authorities cannot be developed without properly defining information needs of specific customer information systems and without most precisely describing objects of interest of the logistics system. It is also not possible to go forward in the development and implementation of logistics information systems after long stagnation unless this important area is considered through a retrospective, identifying and defining problems that accompany the development and introduction of information systems in the military forerunners of the Army of Serbia and the AS now and realizing the current situation in this area in the defense system. In principle, our defense system started the work on the automated collection, processing and distribution of information simultaneously with other developed defense systems in the world. However, in the meantime orientations and concepts changed so that no project focused on the development of integrated automated information system (AIS) and decision support system was brought completely to the end. The development of information systems to support the defense system and particularly the Army faced specific dilemmas and problems which hindered their development: information needs of users which information systems should provide for were never properly defined; disputes occurred between 'generalities' and 'specialists' on whether the system should be built from the bottom (the base) or from the top, resulting in the development of small-scale applications in the base (where problems needing automation occurred) that could fit into a global concept and the development of global concepts never implemented completely into the defense system operational practice. Due to the low level of their information culture, real system experts were not able to properly express and define their needs and expectations of IT professionals who, because of their low levels of general military knowledge, were not able to fully understand the functioning of the real system and information system needs. The above dilemmas and other problems are still present today so that the present automated decision-making support in the defense system (not just in logistics) does not match the needs of practice, requirements of time and modern trends. In treating logistics information systems in this paper, we will apply an analogy with other information systems. Particular aspects and segments of the development and implementation of logistics information systems will be processed with a high degree of generalization, using the experience and research the authors participated in as well as available sources of knowledge. The aforementioned approach allows for a wider general aspect of the given views, while, on the other hand, gaining the depth and accuracy if validly applied to each specific case and to each logistics system. After the organizational changes in the defense system, and in logistics in particular, due consideration should be paid to the development of information systems since there possibly lies the answer to the request 'to reduce the system response time' within a framework of constant reducing the workforce and 'scope of logistic resources'. Changes in the organization of the technical, health, infrastructural and financial support of Defense represent an additional reason to approach more seriously the issues of defense logistic support and the logistic aspects of decision-making in the defense. Introduction GENERAL REMARKS ON INFORMATION SYSTEMS An information management system is a set of bodies and individuals (of a particular organizational system) as well as technical resources and information resources, organizationally and functionally related, with which, based on pre-defined and developed methods and procedures, the tasks of creating, gathering, processing and distribution of data and information are implemented in the given conditions. LOGISTICS SUPPORT INFORMATION Timely disposal of information is a prerequisite for effective command and control in general, and particularly in the areas of logistics support. Considering that modern conditions do not see any decision making regarding the use of armed forces without adequate logistical support, it is of crucial importance for command authorities at all levels to have necessary information on the status of weapons and military equipment and available logistical resources. DOCTRINAL REQUIREMENTS FOR LOGISTICS INFORMATION SYSTEM A logistics support system is a complex military, economic and organizational multilevel system. The mission of logistics, in the sphere of defense, is reflected in planning, creating, developing, launching, supporting and maintaining efficient and effective defense forces. Its task is to provide maneuver, precise effects (fire), comprehensive protection and rational and focused support 'top down' to the Army, at requested location, time, extent and manner, as close as possible to the source of logistic demands and with optimum use of resources. The logistics support system comprises a man, a weapon, an integrated combat system (technical system and the man with all support) and an organizational system (units and institutions), as a whole. LOGISTICS INFORMATION NEEDS A logistics information system needs to process data and provide information relevant to decision makers about logistic objects, i.e. a man, weapons or equipment, animals, integrated combat systems, organizations, infrastructure facilities and installations in order to ensure high-quality execution of all logistic tasks within defined missions, through the entire life cycle of a system (peacetime, crisis situation, state of emergency, mobilization, war). Automated LOGISTICS INFORMATION SYSTEM LOGISTICS (background) automated information system (LAIS) is one of the most important subsystems JAIS and in direct connection with the other subsystems JAIS a. JAIS a set of commands and government agencies (units and institutions) in the defense system, and technical resources and information resources, organizational and functionally related, by which on the basis of forward-defined and developed methods and procedures implemented information security tasks (support) the defense management, in the process of planning, development, training, preparation and use of certain subsystems of defense, while performing the task within the defined mission. Disadvantages logistics EXISTING INFORMATION SYSTEMS The existing logistics information system is derived from previously evolved background information system, which was the part of the unified automated information system (JAIS a). The degree of its efficiency is directly related to the weaknesses of earlier ways of organizing the system of command. A large number of inherited problems is linked to the codification material resources and its applicability in the conduct of inadequate material accounting, inadequate organization of material accountancy and still inadequately constructed a system of reporting on quantitative and qualitative state of material resources and the work of executive bodies of the background (logistics).

113-128

Authors: Cakić Aleksandar B.

INTRODUCTION This paper describes a few different approaches to define the terms 'transport chain' and 'supply chain' aiming at their clarification. TERM TRANSPORT CHAIN The author gives a survey of 'transport' definitions from international, civilian and military, and national literature. Then he gives his definition of a transport chain as a sequence of overall operations, necessary for exchange of goods in time and space within the framework of goods flow during transit from the source to the consumption point. The transport chain is connected neither with the limits of production organizations, particular industrial branches nor other structures of national economy. Transport chains also exist in the Army of Serbia (AS). Optimization of transport chains during peace time has a goal to enable easy and fast selection of an optimal transportation chain. DIFFERENCES AND SIMILARITIES IN DEFINING THE TERMS OF LOGISTIC, SUPPLY AND TRANSPORT CHAIN Modern authors define differently the terms which generally represent similar processes and activities while having almost an identical function. These terms are logistic chain, supply chain and transport chain. For better clarification, these terms are compared herein. Term supply chain The terms supply and supply chain dominate in world literature, as well as supply chain management (SCM), as a specific scientific field. This field is subject to special attention due to its importance in decision-making processes, both strategic and tactical, in companies of all sizes. The Army of Serbia uses the old definition of the term supply, previously used in logistic support, although the AS system of supply with goods and services has moved to logistics principles. The old definition itself, being general and wide enough, is not outdated, so it can be accepted as valid. Term logistic chain The definition of the concept of logistics is followed by the definition of the term logistic chain. Contemporary world literature operates predominantly with the terms supply chains and supply chain management - SCM, rarely with the term logistic chain, which is defined in national literature by several authors. Differences and similarities of notions of transport chain, supply chain and logistic chain It can be noticed that in all chains there are processes such as ordering, packaging, handling (loading, unloading or reloading), transport and storage, with all the activities that are necessary in the implementation of such processes. Also, the elements that realize the processes are similar or the same in all these forms of chains. The objective of all these chains is distribution of goods from the source to the abyss of goods that may be of different forms. However, differences exist when comparing realization subjects as well as organizations that deal with chains. The primary division concerns structures and hierarchy of organizations dealing with chains as well as quantity and quality of information they have at their disposal. The term transport chain is more often applied for physical distribution while the terms of supply and logistic chains are applied from the system, i.e. company's, point of view. The term SCM applies when dealing with overall network of a country/ region, especially with and within international companies. ORGANIZATION AND OPTIMIZATION OF TRANSPORT CHAINS Transport chains are characterized by two main features-technical technological and organizational connection. These two features also characterize the distinction between transport systems and subsystems of the transport chain. Technical-technological connecting of activities in the chain conditions the compatibility of technical resources engaged. Organizational connecting of procedures is carried out by the coordination of information management systems as well as by the coordination of legal and commercial work areas. Transport chains are connected to neighboring systems and the production and consumption of goods. Transport chains optimization Research and identification of optimal transport chain design methods is of considerable significance for the optimization of transport processes. Procedures and means necessary for transport chain functioning are considered as elements while the relations among these elements are conceived as technological and economic relations within a system. Therefore, harmonization of system elements represents the basic function of determining optimal solutions for the implementation of the transport chain. Minimal costs and sometimes minimum time are the optimality and cost-effectiveness criterion for transport chains. Supply chain management (SCM) - explanation of the term Supply chain management is actively managing the activities and relationships of a supply chain to maximize product value and to achieve competitive advantage for a reasonable buyer. It represents constant efforts of companies, or groups of companies, to develop and realize supply chains in the most efficient and most effective way possible. Optimization of logistic chains Optimization of the logistic chain is inseparable from the optimization of logistic systems that are bearers of its realization. Tendencies in optimization of logistic chains and systems change. The projected goal is not any more to better exploit storage capacity, motor pools, loading and transportation systems, but to offer logistic service at request, with the least amount of costs, investments, logistic system capacities, with the shortest reaction time possible and the highest possible quality. CONCLUSION It can be therefore concluded that there are no major differences in the definitions of transport, logistic or supply chains, and that the key difference is in the level of hierarchy, which requires different information when making decisions. Hence the difference in these terms, but in principle the need for optimization is the same. The same or similar methods of optimization are used, and a key premise in optimization is that chains must be considered and optimized in their entity, not by elements, i.e. segments. If all the individual chain elements are optimized, it does not mean that the whole chain is optimized.

166-184

Authors: Milenković Dejan S., Jovanović-Milenković Marina V., Radojičić Zoran A.

Introduction The paper explains the importance and the role of content management systems, gives an overview of the functionality required by such systems and makes a categorization of existing content management systems, thus performing, to some extent, a systematization of this area. Internet technologies and e-business Electronic business is a set of business activities that occur by ICT, especially Internet. CMS existence is conditioned by the development of Internet technology. Basic terminology, problem and solution The basic terms of which problems are considered in this paper are Content, Content Management and Content Management System. Content management systems demand Content management systems demand is reflected in the following: (1) complex structure and a hierarchy of target groups are major challenges for the selection and implementation of an adequate system of content management in decision-making processes; (2) timely adoption of key decisions and their implementation is currently a considerable advantage over competitors; (3) by applying modern information and communication technologies and service-oriented architecture, content, especially documents, management provides security and protection of information in the process of content managing. Content management systems types This article describes the following types of content management systems: Document Management System, Digital Asset Management, Web Content Management and Learning Content Management. Content management systems basic parts The main parts of the content management system are: (1) Content integration, including any content manipulation (input, processing, display); (2) Version control, older versions of files are stored in the database (date of creation/change, and optional comment). Thanks to version control, web site can be restored later (rolled-back) to the previous version; (3) Workflow, allows defining processes in a few steps concerning the creation, review and approval of content publishing; (4) Content repositorium (relational, object or XML databases) greatly improves reuse and content management, especially when these items have a high repetition level; (5) Users management and their privileges; (6) User interface. Display of client and administrative console is done through a web browser; (7) Applications represent an addition to content management systems (business rules, API functions, search, forum, etc.) Content management systems classification Content management systems classification can be performed by different elements: (1) by type, where the content management system is a framework or system; (2) by license; (3) by used technology; (4) by price. The paper briefly explains the classification. Conclusion Future direction of research of content management system applications in the Serbian Army would be based on the advantages and disadvantages of electronic document management system repositories, for example realistic management processes and data flows within the command and information system.