<p style="text-align: justify">U radu su prikazani rezultati ispitivanja energetske efikasnosti ravnih PSE. Cilj istraživanja je uvodenje i definisanje konstruktivnih, fizickih i radnih karakteristika ravnih,<br />niskotemperaturnih prijemnika sunceve energije sa aspekta povecanja energetske efikasnosti. Ispitana je mogucnost efikasnijeg prenosa toplote sa povr&scaron;ine apsorbera na radni medijum cime se smanjuju ukupni toplotni gubici.</p> / <p>In the paper are presented the result of energetic efficiency test of<br />flat plate solar collectors. The aim of test is introduction and<br />definition of constructive, physical and working characteristics of<br />flat plate low-temperature solar collectors from the incresing<br />energetic efficiency aspect. Possibility of higher efficiency of heat<br />transmision from the surface of absorber to the working fluid was<br />tested, with decresing of summary heat losses.</p>

<p>U radu je izvr&scaron;ena detaljna analiza uticajnih faktora na energetsku efikasnost prijemnika sunčeve energije u dinamičkim uslovima rada. Identifikovani su parametri koji utiču na povećanje efikasnosti reprezentativnih tipova prijemnika koji se nalaze u komercijalnoj primeni. Promenom geometrijskih parametara konstrukcije i radnih parametara utvrđen je njihov uticaj na energetsku efikasnost a zatim je kreiran model za ocenu povećanja efikasnosti prijemnika sunčeve energije u dinamičkim uslovima rada.</p>

<p>It is a well-known fact that there are significant differences in production output and business results of farms operating under rather similar natural and socio-economic conditions. Such differences can be attributed to biological factors, specialization level and production intensity, size of farms, implemented production practice, but also to the differences in capabilities of farmers, that is, their managerial capacities.<br />The starting point in selection of subjects for the research was significance of managerial capacities and the fact that not enough attention is dedicated to them, as well as the necessity of urgent improvement of competitiveness in production of poultry meat in our country. Therefore, the subject of the research in this doctoral dissertation is managerial capacities of broiler producers in Vojvodina. When analysing managerial capacities of broiler producers, not only were personal aspects taken into account (gender, age, education level, previous experience, etc.), but the subject of consideration includes characteristics of decision making process (planning, implementation and control) as well. The main objective of the study is to point out to the significance of managerial capacities, possibilities and methods implemented in their assessment, and to establish the reason why some of the broiler producers in Vojvodina, operating under rather similar conditions, are more efficient as compared to other farmers. In order to analyse managerial capacities of broiler producers and to judge whether and to what extent do they influence the production output (technical and economic efficiency), 30 broiler farms of different production capacities, all at the territory of AP Vojvodina, were comprised in the analysis.<br />One of the starting hypotheses in this study considers significant differences in technical and economic efficiency between the selected broiler farms. Technical and economy efficiency indexes, obtained by implemented DEA method, indicate that such hypothesis was justified. The obtained TE indexes point out that broiler producers in Vojvodina are relatively technically efficient (six out of thirty producers achieved maximum level of TE). However, the number of farms that achieved maximum level of EE is much lower (only one out of thirty farms achieves maximum level of EE), which indicates the market difficulties that producers are coping with, but also proves that it is possible to operate better under the existing conditions which are assumed to be the same for all. The number of economically inefficient farms could be reduced through decrease of production costs (primarily reduction of feed costs, increase of operation productivity, reduction of energy costs, etc.), which certainly requires, as one of preconditions, the adequate managerial capacities of producers.<br />The assumption that certain aspects of managerial capacities, such as personal aspects and decision making process, influence TE and EE has been confirmed with the results of Tobit regression. Statistically significant influence of achieved TE and EE is confirmed in 9 out of 82 variables included in the models. This certainly does not mean<br />VIII<br />that other aspects of managerial capacities are not significant, but that under current conditions, relatively small number of variables determines the number of farms that will manage to achieve or at least to nearly achieve &ldquo;the best possible practice&rdquo;.<br />Statistically significant influence was also proven in certain personal aspects of producers, as well as in some aspects of decision making process. Therefore, it is necessary to explain to producers and advisors the significance of the aforesaid aspects and to work on their improvement. The only aspect proven as significant both for TE and EE is the experience of farmers, which only explains the poor working environment that our producers operate in. The conclusion which can be derived from the aforesaid is that the most significant and irreplaceable managerial capacity of broiler producers is their experience. Such experience mainly refers to business relations and acquaintances obtained from long-lasting engagement in broiler production, but also to their ability to find their way and achieve success in conditions of the black economy.<br />The fact that there is no statistical significance in terms of influence of certain aspects of managerial capacities on TE and EE, actually points out to underdevelopment of the required managerial capacities of broiler producers. Therefore, the improvement of managerial abilities must be set as the permanent task, so competitiveness of poultry meat sector could be increased. To this effect, it is necessary to provide constant education through trainings and seminars, as well as regular cooperation with advisory service (particularly in terms of significance of keeping records, planning and control of the achieved results), but also through exchange of experience and cooperation with other producers.</p>

<p>Na regionalnom planu evidentne su potrebe za visokim energetskim performansama, promenom strukture izvora energije i modernizacijom energetske infrastrukture, što zahteva novi i inoviran razvojni put praćen korenitim promenama i sistemskim pristupom a u skladu sa novim društvenim, ekonomskim i tehnološkim prilikama. Takav razvojni put bi učinio regionalne energetske sisteme efikasnim i održivim i predstavlja energetsku tranziciju. Disertacija kombinuje različite tehnike i pristupe za analizu mnogih aspekata razvoja regionalnih energetskih sistema od kojih su najvažniji povećanje energetske efikasnosti u sistemima proizvodnje energije, diversifikaciju izvora energije (kombinovanje obnovljivih i neobnovljivih izvora energije) i poboljšanja u energetskoj infrastrukturi (nova i savremena tehnološka rešenja).</p> / <p>At the regional level, there are evident needs for a high energy performance, change the structure of energy sources and modernization of the energy infrastructure, which requires a new and innovative development path, followed by fundamental changes and systemic approach in accordance with the new social, economic and technological conditions. Such a development path would make regional energy systems efficient and sustainable and represents the energy transition.<br />The thesis combines a variety of techniques and approaches for the analysis of many aspects of the development of regional energy systems, but especially increasing of energy efficiency in energy production systems, diversification of energy sources (a combination of renewable and non-renewable energy sources) and improvements in energy infrastructure (new and modern technological solutions).</p>

<p>U radu se proučava kvalitet vazduha pod pritiskom iz aspekta održive proizvodnje. Zahtevani kvalitet vazduha postiže se primenom filtera<br />i sušača. Filteri vazduha izazivaju pad pritiska, koji ako se smanji,<br />smanjuje se i ukupna količina proizvedenog vazduha pod pritiskom, čime<br />se povećava energetska efikasnost. Utvrđuje se povezanost primene<br />različitih filtera i pada pritiska, uz poštovanje kvaliteta vazduha.<br />Osim toga, analiziran je kondenzat, koji se pri filtraciji javlja u<br />sistemu, i kreirane su odgovarajuće preporuke za njegovo odlaganje, jer<br />se on svrstava u opasan otpad zbog prisustva ulja.</p> / <p>This paper examines the quality of compressed air from the aspect of<br />sustainable production. The required air quality is achieved by using filters<br />and dryers. Air filters generate the pressure drop, which, if reduced, reduces<br />the total volume of produced compressed air, which lead to increase in<br />energy efficiency. Connections between the application of different filters and<br />pressure drops with respect to quality are explored. In addition, the<br />condensate from the compressed air system is analysed, and appropriate<br />recommendations for its disposal are created because it is classified as<br />hazardous waste due to the presence of oil.</p>

<p>U ovom radu je analiziran uticaj Vi&scaron;efrontalne metodologije na povećanje efikasnosti nastavnog procesa na tehničko-tehnolo&scaron;ki orijentisanim fakultetima. Sprovedeni eksperiment je pokazao da ova metodologija pozitivno utiče na ključne parameter kroz koje je moguće definisati efikasnost tako složenog procesa kao &scaron;to je nastava. Poseban akcenat je stavljen na faktor unutra&scaron;nje motivacije, za koji je takođe obrazložen eksperimentom uočen pozitivan uticaj koji ova metoda na njega ostvaruje. U radu su date preporuke za primenu ove metode u visokom &scaron;kolstvu. Uočene su potencijalne pote&scaron;koće u njenoj implementaciji, na osnovu čega su date preoruke za njeno unapređenje i adaptaciju za specifične uslove visokog &scaron;kolstva na tehničko-tehnolo&scaron;kim fakultetima.</p> / <p>In this disertation, the impact of Multi-frontal methodology on increasing the efficiency of the teaching process is analyzed in technically and technologically oriented faculties. The conducted experiments showed that this methodology positively influenced key parameters through which it is possible to define the efficiency of such a complicated process as teaching is. Special emphasis is placed on the inner motivation factor. It was noticed through experimentally conducted analysis that this methodology positively influenced this factor. The dissertation gives recommendations for the application of these methods in higher education. Potential difficulties in its implementation were observed, and recommendations were given for its improvement and adaptation to specific conditions of higher education in technical and technological universities.</p>

<p>Rad se bavi analizom organizacione klime u javnim Preduzećima, sa ciljem identifikacije postojećih problema i davanjem predloga za prevazilaženje istih u cilju stvaranjaa optimalnih organizacionih uslužnih perfomansi.</p> / <p>The paper analyzes the organizational climate of public enterprises, in order to identify existing problems and giving suggestions for overcoming them in order to tap into optimal organizational performance services.</p> / null

<p>Doktorska disertacija se bavi pitanjem oblikovanja i primene inovirajućeg modela nastave grafičkih komunikacija u visokoobrazovnim ustanovama tehničke struke, baziranog na metodi učenja na daljinu. Cilj rada je da prikaže inovativni model<br />učenja, od procesa početne ideje do konačnog oblika, sa posebnim naglaskom na ograničavajuće okolnosti u primeni, na uslove za njegovu uspe&scaron;nost, kao i njegovu empirijsku potvrdu putem merenja uspeha studenata u savladavanju odgovarajućeg nastavnog programa. Glavna hipoteza koja je razvijena i dokazana u okviru ove doktorske disertacije, je da primena modela učenja na daljinu u nastavi grafičkih komunikacija ima statistički značajan uticaj na efikasnost nastavnog procesa u visokom obrazovanju tehničkih struka. U cilju dokazivanja hipoteze primenjen je obrazovni<br />sistem za daljinsko učenje dLearn, za učenje na Tehničkom fakultetu &raquo;Mihajlo Pupin&laquo; u<br />Zrenjaninu, Visokoj tehničkoj &scaron;koli strukovnih studija u Zrenjaninu i Visokoj tehničkoj &scaron;koli u Novom Sadu. Takođe, dizajniran je elektronski materijal za učenje nastavnih sadržaja grafičkih komunikacija, koji predstavlja praktični doprinos teorijskom delu disertacije. U eksperimentalnom delu doktorske disertacije je organizovano daljinsko učenje preko Interneta, izvr&scaron;eno je testiranje i merenje relevantnih parametara od<br />uticaja na efikasnost ovog načina učenja. Eksperimentalni program dokazao je svoje<br />pozitivne efekte na podizanje nivoa uspeha studenata u nastavi grafičkih komunikacija.</p> / <p>The doctoral thesis deals with designing and<br />implementation innovative model of teaching<br />graphic communication in higher education<br />institutions of engineers, based on the method of<br />distance learning. The aim is to present an<br />innovative model of learning from the process of<br />initial ideas to final form, with special emphasis on<br />limiting the circumstances in application,<br />conditions for its success, as well as its empirical<br />confirmation by measuring students&#39; success in<br />mastering the appropriate curriculum. The main<br />hypothesis that was developed and proven in the<br />framework of this dissertation is to use the model of<br />distance learning in teaching graphic<br />communication has a statistically significant effect<br />on the efficiency of teaching process in higher<br />education of technical vocation. In order to prove<br />the hypothesis we used the education system for<br />distance learning dLearn, learning at the Technical<br />Faculty &quot;Mihajlo Pupin&quot; in Zrenjanin and at<br />Technical Colleges of Applied Sciences in Novi Sad<br />and Zrenjanin. Also, electronic material for<br />learning curriculum content of graphic<br />communication is designed, which is a practical<br />contribution to the theoretical part of the<br />dissertation. In the experimental part of the<br />dissertation distance learning via the Internet has<br />been organized, the testing and measurement of<br />relevant parameters have been performed<br />influencing the efficiency of this type of learning.<br />The experimental program demonstrated its<br />positive effects on raising students&rsquo; achievement in<br />teaching graphic communications.</p>

<p>U ovoj disertaciji je kvantitativno određen odnosa energetske<br />efikasnosti i pouzdanosti u bežičnim senzorskim mrežama na<br />fizičkom sloju i sloju kontrole pristupa medijumu. Pronađene<br />su optimalne vrednosti ovog odnosa u smislu vi&scaron;eciljne<br />optimizacije sa Pareto pristupom, bez preferenci.</p> / <p>In this dissertation we quantify energy-efficiency and reliability<br />trade-off in wireless sensor networks at physical and medium<br />access control layers. We find the trade-off optimal solutions in<br />the sense of multi-objective Pareto optimality, without<br />preferences.</p>

<p>U bežičnoj mreži senzora i robota, senzorski moduli vrše nadzor<br />fizičkih veličina od značaja, a roboti imaju ulogu izvršilaca<br />zadataka koji im se dodeljuju primenom odgovarajućeg algoritma. Nakon<br />detekcije događaja od strane statičkih senzorskih čvorova i<br />prosleđivanja informacija o događajima robotima, potrebno je<br />dodeliti zadatke robotima na efikasan način. Dodela zadataka vrši<br />se u skladu sa prirodom različitih scenarija koji se mogu javiti u<br />praksi. U okviru disertacije razmatran je slučaj kada se konkurentno<br />javlja više događaja kojima je potrebno dodeliti izvršioce. U pogledu<br />energetske efikasnosti, u ovakvim sistemima kao ključni problemi<br />javljaju se minimizacija ukupne dužine kretanja robota i optimizacija<br />komunikacije u mreži. Od komunikacinih protokola za otkrivanje<br />izvršilaca, u ovoj disertaciji predstavljena su poboljšanja<br />postojećeg iMesh protokola i uveden je novi vCell protokol zasnovan na<br />lokalizovanom formiranju ćelija Voronoi dijagrama. Takođe,<br />upoređene su performanse novog protokola sa postojećim (pravougaoni<br />kvorum i iMesh) u gustim mrežama, retkim mrežama i mrežama sa<br />rupama u topologiji. Uz to, uvedeni su algoritmi za ažuriranje lokacije<br />kojima mreža reaguje na kretanje robota. Rezultati simulacija pokazuju<br />da vCell postiže efikasnost blizu 100% u nalaženju najbližeg robota u<br />gustim mrežama. U retkim mrežama, efikasnost mu je do 40% bolja u<br />odnosu na ostala rešenja.</p><p>Kao glavni rezultat u disertaciji prikazani su novi algoritmi za<br />dodelu robota kao izvršilaca zadataka događajima, čime su<br />prevaziđni nedostaci više do sada poznatih rešenja ovog problema.<br />Za zadati skup događaja i skup robota, svakom događaju dodeljen je po<br />jedan robot koji je zadužen za obilazak lokacije događaja. Tokom<br />pojedinačnih rundi, robotima je dozvoljen obilazak jednog događaja<br />kada se vrši uparivanje, ili više događaja, kada se vrši<br />sekvencijalna dodela. U distribuiranom slučaju, statički senzorski<br />uređaji detektuju događaje i prijavljuju ih obližnjim robotima.<br />Algoritam PDM koji se odnosi na unapređeno uparivanje sa mogućnošću<br />razmene partnera, eliminiše dugačke ivice koje se mogu javiti<br />prilikom uparivanja. Algoritam SQD za sekvencijalnu dodelu događaja<br />robotima iterativno pronalazi par robot-događaj sa najmanjim<br />međusobnim rastojanjem, uvrštava izabrani događaj u listu za oblazak<br />izabranog robota i ažurira poziciju robota. Takođe su predložene<br />generalizacije koje omogućavaju da događaji budu posećeni od strane<br />više robota i koje uzimaju u obzir vremenska ograničenja.<br />Distribuirani algoritam MAD, koji je zasnovan na iMesh<br />informacionoj strukturi i lokalnim aukcijama u robotskoj mreži,<br />vrši dodelu robota događajima na lokalizovan i energetski efikasan<br />način. Rezultati simulacija potvrđuju prednosti predloženih<br />algoritama u odnosu na postojeća rešenja, kako u pogledu skraćivanja<br />dužina putanja robota, tako i u produženju životnog vremena sistema.</p> / <p>In a typical wireless sensor and robot network, sensor nodes monitor physical<br />values of interest, while robots perform some automated tasks. The tasks are<br />assigned to robots by means of an appropriate algorithm. Upon the<br />occurrence of events which are detected by sensor nodes, the information<br />about the events needs to be delivered to robots. Afterwards, it is necessary<br />to assign tasks to robots in an efficient way. Task assignment is performed<br />according to the nature of different scenarios which might occur in practice.<br />This thesis is focused on the case when multiple events, all of which require<br />to be visited by robots, happen simultaneously. Regarding energy efficiency,<br />the key issues which arise in such systems are minimization of robot travel<br />paths, and optimization of the network traffic. In this thesis, the following<br />service discovery protocols are presented: improvements of the existing<br />iMesh protocol, and the novel vCell protocol, which is based on localized<br />formation of an information structure which resembles Voronoi diagram.<br />Furthermore, the performaces of new vCell protocol is compared with the<br />existing protocols (Quorum and iMesh) in dense networks, sparse networks,<br />and networks with holes in topology. Also, location update algorithms are<br />introduced, which deal with robot mobility. The simulations show that vCell<br />achieves nearly 100% success rate in finding the nearest robot in dense<br />networks. In sparse networks, it outperforms the other existing solutions by up<br />to 40%.<br />As a key contributtion, the novel dispatch lgorithms have been introduced.<br />Given a set of events and a set of robots, the dispatch problem is to allocate<br />one robot for each event to visit it. In a single round, each robot may be<br />allowed to visit only one event (matching dispatch), or several events in a<br />sequence (sequence dispatch). In a distributed setting, each event is<br />discovered by a sensor and reported to a robot. In this thesis, novel<br />algorithms are presented, whichh are aimed at overcoming the shortcomings<br />of several existing solutions. Pairwise distance based matching algorithm<br />(PDM) eliminates long edges by pairwise exchanges between matching pairs.<br />Sequence dispatch algorithm (SQD) iteratively finds the closest event-robot<br />pair, includes the event in dispatch schedule of the selected robot and<br />updates its position accordingly. When event-robot distances are multiplied by<br />robot resistance (inverse of the remaining energy), the corresponding energybalanced<br />variants are obtained. Also, generalizations are introduced which<br />handle multiple visits and timing constraints. Distributed algorithm MAD is<br />based on information mesh infrastructure and local auctions within the robot<br />network for obtaining the optimal dispatch schedule for each robot. The<br />simulations conducted confirm the advantages of our algorithms over other<br />existing solutions in terms of average robot-event distance and lifetime.</p>