Mission critical ICT

In this paper, three technologies intended to be implemented in Private Mobile Radio systems are analyzed and compared: TETRA (Terrestrial Trunked Radio), LTE (Long Term Evolution) and DMR (Digital Mobile Radio). Characteristics of these networks are collected and compared in one SWOT table. Based on this analysis, appropriate recommendations are made, which should be taken into account when choosing a specific solution for specific uses in Critical Communications systems

Ispitivanje produktivnosti krompira u zavisnosti od porekla sadnog materijala i veličine semenske krtole

The aim of this study was to determine the impact of the origin of planting material and size of seed tubers, on the productive properties of most commonly grown potato cultivars Cleopatra, Jaerla, Desiree and Kennebec in Western Serbia (Macva). Potato seed-producing crop, from which the planting material came from, was grown during 2007 at two sites with different altitude: a plain region 72 m a.s.l. and a mountainous region 1100 m a.s.l. Evaluating the presence of the two most widespread potato virus (PYV) and (PLRV in our conditions was performed by ELISA test. The investigation was carried out by planting the following mass of planted material: 50 ± 5g, 70 ± 5g, 90 ± 5g and 110 ± 5g in 2008 year. Planted tubers originating from 72 m a.s.l. produced a total yield of 29.10 t ha1- .The difference was higher than the variant with planted tubers originating from 1100 m a.s.l. by 1.30 t ha1- (4.50 %). The highest total yield of 30.80 t ha1- was achieved by planting the largest mass (110 g) and the lowest 25.50 t ha1- by planting the smallest mass (50 g) of the tuber.Cilj rada je bio da se utvrdi uticaj porekla sadnog materijala i veličine semenske krtole na produktivne osobine četiri najčešće gajene sorte krompira Cleopatra, Jaerla, Desiree i Kennebec u uslovima Zapadne Srbije (Mačve). Proizvodnja sadnog materijala krompira izvedena je 2007. godine u dva lokaliteta različite nadmorske visine (nv): ravničarskom 72 m i planinskom regionu 1100 m (nv). Ocena prisustva dva i najraširenija virusa krompira u našim uslovima (PYV) i (PLRV) izvršeno je ELISA testom. Istraživanja su izvedena sadnjom semenskih krtola prosečne mase 50 ± 5g, 70 ± 5g, 90 ± 5g i 110 ± 5g tokom 2008. godine. Sađenjem krtola poreklom sa 72 m nv. u proseku ostvaren je ukupan prinos od 29,10 t ha1-. Razlika je veća od varijanti gde su sađene krtole poreklom sa 1100 m nv. za 1,30 t ha1-, ili za 4,50 %. Najveći ukupan prinos krtola od 30,80 t ha1- dobijen je sadnjom najkrupnije frakcije prosečne mase 110 g, a najmanji 25,50 t ha 1- sadnjom najsitnije frakcije prosečne mase 50 g

Cluster formation techniques in hierarchical routing protocols for Wireless Sensor Networks

Abstract: Wireless sensors are an irreplaceable link in the chain of global networking today. There is almost no area of human activity where they are still not used, and they will be used in the near future almost everywhere. Wireless sensor networks consist of a large number of sensor nodes that are arranged (usually randomly) in an area. The main problem is the limited power supply. Sensors are usually powered by the battery which is not possible to replace. The lifetime of the network depends on the duration of battery power of sensor nodes. The largest part of the consumed energy goes for communication with the rest of the network. Therefore, the selection of good routing protocol is essential for the long life-span of the network. There are a large number of proposed protocols and they can be divided into several groups, depending on the approach to the problem. In this paper we present a family of hierarchical protocols, their common features and specific implementation, we will present advantages and disadvantages as well as possible directions of further development

Measuring the Characteristics of DG CAC Algorithm

Users today expect email and instant messaging access, surf, video games and other services through mobile broadband access networks. In order to support this increasing data traffic, advanced resource management has to be implemented. As CAC (Call Admission Control) algorithm plays an important role in this resource management, comparing of two proposed call admission control algorithms has been done in this paper. Algorithms are tested in simulation environment, for two different periods of time. They showed expected characteristics in both 1000 and 10000 seconds periods, and newly proposed DG CAC algorithm showed better results than other algorithm, in number of handover requests, and in the way of returning resources to degraded connections

The Art of Wine

This book is a result of collaboration between the Municipality of Negotin and Faculty of Architecture, University of Belgrade that has started in 2011. Through several “Public Art and Public Space” elective courses, more than 100 students, from both levels of study, bachelor level, as well as master level, were able to work, through the wide participatory process, on areas of the Negotin Municipality, especially on the famous wine cellars called: “Negotinske Pivnice”. The aim of the student projects was to research the architecture, urbanism, landscape architecture, aquatorial (Danube) potential, heritage and art synergy in the function of rural economy development of the area. Until 2013., numerous presentations, with exhibitions “VinoGrad - The Art of Wine” was realized at the Faculty of Architecture, University of Belgrade and in the city of Negotin, as well. After all, some of these student projects were implemented. The team consisted of students, professors and experts, from Serbia and from abroad, build a strong bond and cooperation between the Faculty of Architecture and the Municipality of Negotin. Fruitful working environment provided during years involved many other participants from Serbia and abroad. After all, the important contribution to the book is cultural landscape research done by students and professors from Landcspe Architecture, Faculty of Forestry, University of Belgrade. The whole project was supported by Die Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ), local Municipality of Negotin and local communities of wine producer’s villages

Adaptive control of call acceptance in WCDMA network

In this paper, an overview of the algorithms for access control in mobile wireless networks is presented. A review of adaptive control methods of accepting a call in WCDMA networks is discussed, based on the overview of the algorithms used for this purpose, and their comparison. Appropriate comments and conculsions in comparison with the basic characteristics of these algorithms are given. The OVSF codes are explained as well as how the allocation method influences the capacity and probability of blocking.. Introduction We are witnessing a steady increase in the number of demands placed upon modern wireless networks. New applications and an increasing number of users as well as user activities growth in recent years reinforce the need for an efficient use of the spectrum and its proper distribution among different applications and classes of services. Besides humans, the last few years saw different computers, machines, applications, and, in the future, many other devices, RFID applications, and finally networked objects, as a new kind of wireless networks "users". Because of the exceptional rise in the number of users, the demands placed upon modern wireless networks are becoming larger, and spectrum management plays an important role. For these reasons, choosing an appropriate call admission control algorithm is of great importance. Multiple access and resource management in wireless networks Radio resource management of mobile networks is a set of algorithms to manage the use of radio resources with the aim is to maximize the total capacity of wireless systems with equal distribution of resources to users. Management of radio resources in cellular networks is usually located in the base station controller, the base station and the mobile terminal, and is based on decisions made on appropriate measurement and feedback. It is often defined as the maximum volume of traffic load that the system can provide for some of the requirements for the quality of service. Resource management should preserve the capacity and distribute a proper allocation among users. It has an important place in various commercial networks such as GSM and WCDMA (UMTS), but also in professional networks and network security organizations, such as PMR and PAMR, including TETRA network. Location and design of radio resource Radio resource management is performed in the radio access networks and mobile terminals. The objectives of the management of radio resources are defined to allow the execution of the following tasks: to guarantee QoS for different applications, maintenance of the planned coverage, and capacity optimization of the system. Various new services have different needs, so it is no longer possible to pre-allocate resources correctly or to full-dimension network in advance. Main types of algorithms for access control In fixed networks, resources are planned in a static way, and the management of resources is quite easy. Mobile networks enable mobility which includes unanticipated movements and possible grouping of users. Mobility brings new qualities such as freedom of service on the move, but also a new assignment for the operator - preserving the continuity of services, or signal covering the territory of interest, and providing sufficient capacity to users and quality handover realization. Resource management in networks with hard capacities Due to the nature of wireless networks, radio resources such as transmission power of base stations and used radio-spectrum are generally limited. Networks with hard capacities are limited by the number of channels. In order to provide services with good quality and large capacity, advanced methods to share the available radio spectrum in the most efficient ways are needed. The methods of sharing spectrum are called multiple access techniques. Access management in a 3G network based on the user count The direct relation between the number of users and the system capacity is very characteristic in networks with hard capacities. For systems with so-called "Soft" capacity, there is no direct relationship between the number of users and available capacity for incoming requests, and the number of served users depends on the SIR threshold. However, there is the algorithm that follows a very simple approach in which decisions about access are based only on the number of users already present in the system. The use of the algorithm represents a direct mapping of strategies from 2G systems in which the capacity is limited  with hard boundaries, and a decision is made on the basis of already admitted users in the system. The methods of resource management used in modern wireless networks In previous research of access control algorithms in wireless networks, in the broadest terms, two basic methods could be used: deterministic and stochastic methods. Deterministic algorithms imply that QoS parameters are one hundred percent guaranteed for the duration of the connection, which is not practical in real systems. In the stochastic CAC algorithms, QoS cannot be guaranteed one hundred percent, but instead, with a certain probability. Resource reservation Methods with reserved channels, or generally speaking the reserved resources, are known in the literature as Guard Channel or GC methods. Algorithms with static reservation often result in poor utilization of resources. Algorithms with dynamic thresholds have the threshold that adapts to real  needs (for example, if at the particular location many requests for handover connections appear, then the part of the resources saved for handover can dynamically be increased). Influence of the OVSF codes distribution method to the number of accepted requests in the WCDMA network The OVSF codes are used in WCDMA networks to support different transmission rates for multimedia services. They are variable in length, and using a smaller factor achieves higher transmission rates. In recent years, a significant number of papers have been devoted to efficient allocation of these codes aiming to maximize system capacity and reduce the probability of rejection of connection requests. OVSF code allocation algorithms are usually designed in association with CAC algorithms in order to perform universal capacity management in access networks. Conclusion Given the great importance of resource management in wireless networks and the importance of a proper choice of the control algorithm, the algorithms for the admission control in mobile wireless networks are analyzed. A special attention is given to the algorithms for the admission control in WCDMA networks. In this regard, the point is made to some of the specifics of the WCDMA technology, which affect the choice of algorithm work modes.</p

Ispitivanje produktivnosti krompira u zavisnosti od porekla sadnog materijala i veličine semenske krtole

The aim of this study was to determine the impact of the origin of planting material and size of seed tubers, on the productive properties of most commonly grown potato cultivars Cleopatra, Jaerla, Desiree and Kennebec in Western Serbia (Macva). Potato seed-producing crop, from which the planting material came from, was grown during 2007 at two sites with different altitude: a plain region 72 m a.s.l. and a mountainous region 1100 m a.s.l. Evaluating the presence of the two most widespread potato virus (PYV) and (PLRV in our conditions was performed by ELISA test. The investigation was carried out by planting the following mass of planted material: 50 ± 5g, 70 ± 5g, 90 ± 5g and 110 ± 5g in 2008 year. Planted tubers originating from 72 m a.s.l. produced a total yield of 29.10 t ha1- .The difference was higher than the variant with planted tubers originating from 1100 m a.s.l. by 1.30 t ha1- (4.50 %). The highest total yield of 30.80 t ha1- was achieved by planting the largest mass (110 g) and the lowest 25.50 t ha1- by planting the smallest mass (50 g) of the tuber.Cilj rada je bio da se utvrdi uticaj porekla sadnog materijala i veličine semenske krtole na produktivne osobine četiri najčešće gajene sorte krompira Cleopatra, Jaerla, Desiree i Kennebec u uslovima Zapadne Srbije (Mačve). Proizvodnja sadnog materijala krompira izvedena je 2007. godine u dva lokaliteta različite nadmorske visine (nv): ravničarskom 72 m i planinskom regionu 1100 m (nv). Ocena prisustva dva i najraširenija virusa krompira u našim uslovima (PYV) i (PLRV) izvršeno je ELISA testom. Istraživanja su izvedena sadnjom semenskih krtola prosečne mase 50 ± 5g, 70 ± 5g, 90 ± 5g i 110 ± 5g tokom 2008. godine. Sađenjem krtola poreklom sa 72 m nv. u proseku ostvaren je ukupan prinos od 29,10 t ha1-. Razlika je veća od varijanti gde su sađene krtole poreklom sa 1100 m nv. za 1,30 t ha1-, ili za 4,50 %. Najveći ukupan prinos krtola od 30,80 t ha1- dobijen je sadnjom najkrupnije frakcije prosečne mase 110 g, a najmanji 25,50 t ha 1- sadnjom najsitnije frakcije prosečne mase 50 g