The electric power distribution system usually operates a radial configuration, with tie switches between circuits to provide alternate feeds. The losses would be minimized if all switches were closed, but this is not done because it complicates the system's protection against overcurrents. Whenever a component fails, some of the switches must be operated to restore power to as many customers as possible. As loads vary with time, switch operations may reduce losses in the system. Both of these are applications for reconfiguration. The problem is combinatorial, which precludes algorithms that guarantee a global optimum. Most existing reconfiguration algorithms fall into two categories. In the first, branch exchange, the system operates in a feasible radial configuration and the algorithm opens and closes candidate switches in pairs. In the second, loop cutting, the system is completely meshed and the algorithm opens candidate switches to reach a feasible radial configuration. Reconfiguration algorithms based on linearized transshipment, neural networks, heuristics, genetic algorithms, and simulated annealing have also been reported, but not widely used. These existing reconfiguration algorithms work with a simplified model of the power system, and they handle voltage and current constraints approximately, if at all. The algorithm described here is a constructive method, using a full nonlinear power system model that accurately handles constraints. The system starts with all switches open and all failed components isolated. An optional network power flow provides a lower bound on the losses. Then the algorithm closes one switch at a time to minimize the increase in a merit figure, which is the real loss divided by the apparent load served. The merit figure increases with each switch closing. This principle, called discrete ascent optimal programming (DAOP), has been applied to other power system problems, including economic dispatch and phase balancing. For reconfiguration, the DAOP method's greedy nature is mitigated with a backtracking algorithm. Approximate screening formulas have also been developed for efficient use with partial load flow solutions. This method's main advantage is the accurate treatment of voltage and current constraints, including the effect of control action. One example taken from the literature shows how the DAOP-based algorithm can reach an optimal solution, while adjusting line voltage regulators to satisfy the voltage constraints. / Ph. D.

"Electrohydrodynamic (EHD) pumping relies on the interaction between electrical and flow fields in a dielectric fluid medium. Advantages such as simple and robust design as well as negligible vibration and noise during operation make EHD conduction pumping suitable for various applications. This work investigates meso-scale EHD conduction pumping used as an active flow distribution control mechanism for thermal management systems. Two different scenarios are considered for this purpose: alteration of uniform flow distribution and flow maldistribution correction. Its capability of actively controlling the flow distribution is examined in terms of the value of applied potential for initiation of flow divergence or flow equalization and the flow rate difference between each branch. Experimental results confirm that the reverse pumping direction configuration of EHD pumping is more effective than the same pumping direction configuration. A fundamental explanation of the heterocharge layer development is provided for the effect of flow direction on EHD conduction pumping performance. This study also involves a macro-scale EHD conduction pump used as an alternative mechanism of mixing liquid within a storage tank, for example under low-g condition. A numerical analysis of a simplified model of the experimental setup is provided to illustrate the liquid mixing and thermal homogenization process. The experimental and numerical study provide fundamental understanding of liquid mixing and thermal homogenization via EHD conduction pumping. Liquid-vapor phase change phenomena are used as effective mechanisms for heat transfer enhancement and have many applications such as HVAC&R systems. With this in mind, two detailed studies in pool boiling and in-tube flow condensation are carried out. Specifically, nucleate pool boiling on nano-textured surfaces, made of alumina ceramic substrate covered by electrospun nanofiber, is experimentally investigated. Also, the role of surface roughness and orientation in pool boiling is experimentally characterized. The in-tube convective condensation of pure water in mini-channels under sub-atmospheric pressure is also experimentally explored. This study provides valuable information for the design of condensers in a vapor compression cycle of HVAC&R systems using water as the refrigerant, this process has zero global warming potential. "

<p>Poslednjih godina u balkanskom regionu pa i u Srbiji, zabeleņeno je ńirenje i invazivne korovske vrste Asclepias syriaca. Pretpostavlja se da je u Srbiju dospela iz susedne MaĎarske gde se dugi niz godina gajila kao medonosna biljka. Zahvaljujući alelopatskim osobinama i jakoj kompetitivnosti, ova vrsta ne dozvoljava regeneraciju starih peńčanih polja Najčeńće se javlja u zapuńtenim voćnjacima i vinogradima, na peskovitim terenima pored puteva i ņelezničkih pruga, nasipima, formirajući pri tom čiste sastojine asocijacije ili se javlja sa joń nekoliko korovskih vrsta ali uz apsolutnu dominaciju A. syriaca. Konstatovano je njeno ńirenje sa parloga na obradive povrńine na kojima obrazuje &bdquo;oaze&ldquo;, naročito u usevima pńenice, ječma, suncokreta, soje, u uljanoj repici, voćnjacima i vinogradima. Imajući u vidu sve negativne aspekte nekontrolisanog ńirenja A. syriaca na ruderalnim i poljoprivrednim povrńinama, ciljevi rada bili su praćenje ńirenja i izučavanje njenih biolońkih i ekolońkih karakteristika kao i utvrĎivanje mogućih načina za njeno suzbijanje. Populacija svilenice na teritoriji Vojvodine ima tendenciju ńirenja i ustaljivanja posebno uz puteve i vodene tokove. UtvrĎena je na skoro svim tipovima zemljińta u Vojvodini. Uspeva na zemljińtima od slabo do jako karbonatnih, kao i od slabo do jako humusnih. Podnosi zemljińta čiji je sadrņaj pristupačnih oblika fosfora i kalijuma ispod donje granice optimalne obezbeĎenosti zemljińta, ali i na zemljińtima gde je sadrņaj vrlo visok do ńtetan. Analizom biolońkog spektra sastojina ass. Asclepiadetum syriacae L&aacute;nikov&aacute; in Chytr&yacute; 2009, utvrĎeno je da su one hemikriptofitsko-terofitskog karaktera sa dominacijom hemikriptofita. Godińnja produkcija semena A. syriaca po m2 je od 1.336,53 do 10.109,61, a sa povećanjem gustine biljaka po jedinici povrńine smanjuje se produkcija plodova. Udeo semena svilenice u ispitivanoj zemljińnoj banci semena je vrlo nizak pa A. syriaca ne formira permanentnu banku semena. Dormantnost semena prekida se njegovim izlaganjem niņim temperaturama tokom nekoliko meseci a vlaga igra značajnu ulogu u povećanju klijavosti semena.<br />Alelopatska svojstva svilenice potvrĎena su ispitivanjem uticaja vodenog ekstrakta iz korena na klijavost semena kukuruza, soje i suncokreta u koncentracijama 0,05-0,1g suvemase korena po 1ml destilovane vode. UtvrĎena je i značajna osetljivost gajenog i divljeg sirka na primenjene ekstrakte. Od ekstrakata korena svilenice pripremljenih sa različitim rastvaračima, najveći inhibitorni uticaj na klijavost semena soje imao je butanolni, a na klijanje semena gajenog sirka etil-acetatni i butanolni ekstrakt. Isto je i sa divljim sirkom i ńtirom, dok na klijavost semena kukuruza i soje ni jedan primenjeni ekstrakt nije imao negativan uticaj u značajnijoj meri. Ogledi u poljskim uslovima pokazali su uticaj alelohemikalija iz korena A. syriaca na redukciju prinosa kukurza i sirka. Vodeni ekstrakt korena u koncentraciji primene 0,04g/ml umanjio je prinos kukuruza za 10-15%, krmnog sirka za 12,5% a sirka metlańa za 23%. Ispitivanja mogućnosti hemijskog suzbijanja A.syriaca u poljskim uslovima pokazali su najveću efikasnost herbicida na bazi glifosata, 2,4-D i tembotriona. kao i nakon trogodińnje primene bentazona, bentazona + dikambe, a najmanja efikasnost ustanovnjena je prilikom primene dikambe. Terbutilazin i klomazon u većim preporučenim količinama primene efikasno suzbijaju svilenicu iz semena ako se herbicidi primene pre nicanja, dok imazamoks i oksasulfuron efikasno suzbijajuu tek iznikle biljke svilenice kada se u preporučenim dozama tretiraju biljke u fazi 2-4 lista.</p> / <p>In previous years in the Balkan region, including Serbia, spread of invasive weed species Asclepias syriaca L. was recorded. It supposedly arrived to Serbia from neighbouring Hungary, where it was grown as honey plant. Due to allelopathic properties and strong concurrence, this species does not allow regeneration of old sand fields. It is most common in neglected orchards and vineyards, sandy terrains along roads and railways, embankments, where form pure A. syriaca association, or several additional weed species occur, but with absolute dominance of this weed. From uncultivated areas on which it forms &quot;oasis&quot; its spread was noted especially in wheat, barley, sunflower, soybean, rapeseed crops, in orchards and vineyards. Considering all negative aspects of uncontrolled spread of A. syriaca on ruderal and agricultural areas, the aims of the paper were monitoring of its spread and the study of biological and ecological properties, as well as the establishment of possible ways of its control. On the territory of Vojvodina, common milkweed population has a tendency of spread and colonization, particularly near roads and water flows. It is established on almost all soil types in Vojvodina. It grows on poor to very calcareous soils, as well as on poor to very humic ones. Common milkweed withstands soil with the content of available forms of phosphorous and potassium below the optimum , but also the soils with high to damaging content of these elements. The analysis of the biological spectrum of stands of ass. Asclepiadetum syriacae, L&aacute;nikov&aacute; in Chytr&yacute; 2009, established that it is hemicryptophyte and therophytein, with a domination of hemicryptophytic character.<br />Annual seed production of A. syriaca seed per m2 is from 1.336,53 to 10.109,61, and with the increase in plant density per unit area, production of fruits is reduced. The share of milkweed seed in soil seed bank is very low, and therefore A. syriaca does not form permanent seed bank. Seed dormancy is stopped by its exposure to lower temperatures for several months, and moisture has an important role in the<br />increase in seed germination. Allelopathic properties of common milkweed were confirmed by examination of root water extract effects on maize , soybean and sunflower seed germination at concentrations of 0.05-0.1g of dry root weight per 1ml of distilled water. Significant susceptibility of cultivated sorghum and Johnson grass to the applied extract was recorded. From common milkweed root extracts prepared by various solvents, the highest inhibiting effect to soybean seed germination had butanol extract, and to germination of seed of cultivated sorghum, ethyl acetate and butanol extract. It was the same with wild sorghum and redroot pigweed while none of the applied extracts had significantly negative effect on maize and soybean germination. In field trials, allelochemicals from A. syriaca root reduced maize and millet yield. Root water extracts at the applied concentration of 0.04g/ml reduced maize yield by 10-15%, of fodder sorghum by 12.5% and broomcorn by 23%. In studies regarding chemical control of A.syriaca in field conditions,the highest efficiency was recorded for herbicides based on glyphosate, 2.4-D and tembotrione, as well as for bentazone and bentazone + dicamba after tree-years long application.Dicamba was recorded as the least efficient. Terbuthylayine and clomazone herbicides in pre-emergence application at higher label rates efficiently control common milkweed from seed, while imazamox and oxasulfuron applied at lable rates efficiently control young plants of common milkweed at the phase of 2-4 leaves.</p>

A distribuição de uma Base de Dados convencional caracteriza-se pela necessidade dos dados estarem disponíveis, ao mesmo tempo, a todos os usuários, de modo que os problemas de conflito devido à concorrência para obtenção dos mesmos, tornam-se muito acentuados. A Base de Dados apoiada no Modelo de Representação de Objetos(MRO), devido a suas características semânticas,oferece o suporte necessário para atendimento das necessidades de distribuição num ambiente de desenvolvimento de projetos. Neste trabalho e feita uma proposta de um modelo lógico e funcional para a distribuição da Base de Dados apoiada no MRO. Esta distribuição se caracteriza pela disponibilidade dos dados de forma que cada item (objeto) da base cópia possua um tipo de ligação com a base original. Foram definidos cinco tipos de ligação: apenas leitura (r-), isolado(is), flagrante(fl), mutuamente exclusivo(me)e independente(in). Com isto, tanto a base cópia como a original, respeitando as limitações impostas pelo tipo de ligação entre as mesmas, podem evoluir, e depois de um determinado tempo sofrerem um processo de integração, que também e caracterizado pelo tipo de ligação entre a base original e cópia. / One of the most important characteristics of Distributed Database Systems is the permanent availability of data to all users every same time. This situation emphasizes the conflicts occurring due to the needs of users competing for the same data. Due to its semantics characteristics, the Database Management Systems based on the Object Representation Model (MRO) offer support to meet the distribution needs of computer-aided project development environments. In this work, a functional and logical model for the distribution of MRO based databases are presented. Distribution is characterized based on the required availability of each data item. Each item (object) in each copy database has a link of a specific link to the original database. Five types of links were defined: read only(r-), isolated(is), snapshot(fl), mutually exclusive(me) and independent(in). This arrangement allows both the copy and the original database to evolve in parallel, restricted by the limits imposed by the kinds of links between them. After a while, the copy and the original databases may enter into an integration process, which is also governed by these links.

Este trabalho faz um levantamento dos Sistemas de Iluminação Automáticos (SIA) utilizados atualmente, das tecnologias empregadas e das linhas de pesquisas que vêm surgindo neste tema. É analisada também a relação dos sistemas de controle distribuído (SCD) com os SIA e com a automação predial. Um estudo de caso de um SIA que utiliza um SCD como plataforma tecnológica também é analisado. Ao final da dissertação, propõe-se uma tese, fruto das análises feitas durante este trabalho, que visa aumentar a modularidade, a flexibilidade e a interoperabilidade dos sistemas de automação predial baseados em SCD. Durante a dissertação são descritas: as características da luz; a relação entre a luz e o ser humano; os principais componentes de um SIA; as características básicas de um SCD; e a tecnologia Lonworks. / This work describes the Illumination Automatic Systems (IAS) used nowadays, the used technologies and the research lines that arise in this knowledge area. It\'s also analyzed the relation between Distributed Control Systems (DCS), IAS and building automation. A case study is done with a system that uses IAS and DCS. In the end of this work, it\'s suggested a thesis, result of analyses done during this work, with the objective of increasing the modularity, flexibility and interoperability of buildings automation systems based on DCS technologies. During this dissertation is described: the light characteristics; the relation between light and the human being; the main components of IAS; the characteristics of a DCS; and the Lonworks technology.

Este trabalho faz um levantamento dos Sistemas de Iluminação Automáticos (SIA) utilizados atualmente, das tecnologias empregadas e das linhas de pesquisas que vêm surgindo neste tema. É analisada também a relação dos sistemas de controle distribuído (SCD) com os SIA e com a automação predial. Um estudo de caso de um SIA que utiliza um SCD como plataforma tecnológica também é analisado. Ao final da dissertação, propõe-se uma tese, fruto das análises feitas durante este trabalho, que visa aumentar a modularidade, a flexibilidade e a interoperabilidade dos sistemas de automação predial baseados em SCD. Durante a dissertação são descritas: as características da luz; a relação entre a luz e o ser humano; os principais componentes de um SIA; as características básicas de um SCD; e a tecnologia Lonworks. / This work describes the Illumination Automatic Systems (IAS) used nowadays, the used technologies and the research lines that arise in this knowledge area. It\'s also analyzed the relation between Distributed Control Systems (DCS), IAS and building automation. A case study is done with a system that uses IAS and DCS. In the end of this work, it\'s suggested a thesis, result of analyses done during this work, with the objective of increasing the modularity, flexibility and interoperability of buildings automation systems based on DCS technologies. During this dissertation is described: the light characteristics; the relation between light and the human being; the main components of IAS; the characteristics of a DCS; and the Lonworks technology.

A distribuição de uma Base de Dados convencional caracteriza-se pela necessidade dos dados estarem disponíveis, ao mesmo tempo, a todos os usuários, de modo que os problemas de conflito devido à concorrência para obtenção dos mesmos, tornam-se muito acentuados. A Base de Dados apoiada no Modelo de Representação de Objetos(MRO), devido a suas características semânticas,oferece o suporte necessário para atendimento das necessidades de distribuição num ambiente de desenvolvimento de projetos. Neste trabalho e feita uma proposta de um modelo lógico e funcional para a distribuição da Base de Dados apoiada no MRO. Esta distribuição se caracteriza pela disponibilidade dos dados de forma que cada item (objeto) da base cópia possua um tipo de ligação com a base original. Foram definidos cinco tipos de ligação: apenas leitura (r-), isolado(is), flagrante(fl), mutuamente exclusivo(me)e independente(in). Com isto, tanto a base cópia como a original, respeitando as limitações impostas pelo tipo de ligação entre as mesmas, podem evoluir, e depois de um determinado tempo sofrerem um processo de integração, que também e caracterizado pelo tipo de ligação entre a base original e cópia. / One of the most important characteristics of Distributed Database Systems is the permanent availability of data to all users every same time. This situation emphasizes the conflicts occurring due to the needs of users competing for the same data. Due to its semantics characteristics, the Database Management Systems based on the Object Representation Model (MRO) offer support to meet the distribution needs of computer-aided project development environments. In this work, a functional and logical model for the distribution of MRO based databases are presented. Distribution is characterized based on the required availability of each data item. Each item (object) in each copy database has a link of a specific link to the original database. Five types of links were defined: read only(r-), isolated(is), snapshot(fl), mutually exclusive(me) and independent(in). This arrangement allows both the copy and the original database to evolve in parallel, restricted by the limits imposed by the kinds of links between them. After a while, the copy and the original databases may enter into an integration process, which is also governed by these links.

With the advent of HTML5 as the new standard, web pages became an alternative to native Android and iPhone applications, what made it possible to reduce time and cost of app development and maintenance processes.This thesis is aimed for finding, analyzing and documenting experience and criteria that have weight in a selection of the technology for development of search apps. To achieve this, were developed and compared three alternative client apps (Web-based HTML5, Android and iOS).The results of the thesis provides recommendations for selection the appropriate alternative for the successful development strategy, overview of the problems which may occur during development process, pros and cons of a plain Web-based solution, a Web-hybrid solution, and native Android/iOS solutions that are evaluated for a search intensive apps.

Yes / This paper presents a new control strategy for stochastic distribution shape tracking regarding non-Gaussian stochastic non-linear systems. The objective can be summarised as adjusting the probability density function (PDF) of the system output to any given desired distribution. In order to achieve this objective, the system output PDF has first been formulated analytically, which is time-variant. Then, the PDF vectorisation has been implemented to simplify the model description. Using the vector-based representation, the system identification and control design have been performed to achieve the PDF tracking. In practice, the PDF evolution is difficult to implement in real-time, thus a data-driven extension has also been discussed in this paper, where the vector-based model can be obtained using kernel density estimation (KDE) with the real-time data. Furthermore, the stability of the presented control design has been analysed, which is validated by a numerical example. As an extension, the multi-output stochastic systems have also been discussed for joint PDF tracking using the proposed algorithm, and the perspectives of advanced controller have been discussed. The main contribution of this paper is to propose: (1) a new sampling-based PDF transformation to reduce the modelling complexity, (2) a data-driven approach for online implementation without model pre-training, and (3) a feasible framework to integrate the existing control methods. / This paper is partly supported by National Science Foundation of China under Grants (61603262 and 62073226), Liaoning Province Natural Science Joint Foundation in Key Areas (2019- KF-03-08), Natural Science Foundation of Liaoning Province (20180550418), Liaoning BaiQianWan Talents Program, i5 Intelligent Manufacturing Institute Fund of Shenyang Institute of Technology (i5201701), Central Government Guides Local Science and Technology Development Funds of Liaoning Province (2021JH6/10500137).

<p>Ambrosia artemisiifolia L., invazivna korovsko-ruderalna biljka, poslednjih<br />godina u na&scaron;oj zemlji predstavlja izuzetno veliki problem, ne samo za poljoprivredu<br />nego i za stanovni&scaron;tvo, izazivajući svojim polenom jake alergijske i druge zdravstvene<br />komplikacije. Shvatajući probleme koje ona izaziva, sve zemlje u kojima ambrozija<br />predstavlja veliki, pre svega zdravstveni problem, ulažu ogromne napore, izdvajaju<br />velika finansijska sredstva, organizuju stanovni&scaron;tvo, &scaron;kole, vojsku, javne službe,<br />sredstva informisanja, donose zakone, uredbe i deklaracije, da bi ograničili njeno<br />&scaron;irenje i osigurali njeno suzbijanje, dok se u na&scaron;oj zemlji jo&scaron; uvek nedovoljno ozbiljno<br />shvata ovaj problem.<br />Kako se radi o biljci koja se razmnožava samo generativno (semenom), istraživanja<br />&#39;&#39;banke semena&#39;&#39; pelenaste ambrozije u određenim zemlji&scaron;nim profilima omogućavaju<br />preciznu prognozu njene pojave na određenim stani&scaron;tima, &scaron;to kasnije znatno olak&scaron;ava<br />suzbijanje kako mehaničkim putem tako i primenom herbicida. Zemlji&scaron;ni uzorci za<br />analizu rezervi semena su uzeti, sa karakterističnih ruderalnih stani&scaron;ta, na području<br />Novi Sad, Zrenjanin i Ruma. Obzirom da se radi o ruderalnim stani&scaron;tima, na svim<br />istraživanim lokalitetima utvrđena je relativno visoka brojnost semena pelenaste<br />ambrozije. Prikazano istraživanje je prvo ovog tipa sprovedeno na teritoriji Republike<br />Srbije.<br />Ova proučavanja su od izuzetnog naučnog značaja budući da obuhvataju poznavanje<br />osnovnih biolo&scaron;kih osobina semena ambrozije, kao &scaron;to su morfolo&scaron;ke osobine,<br />karakteristike klijanja, nicanja i načina rasprostiranja.<br />Za potrebe ispitivanja klijavosti semena A. artemisifolia 2007. godine sa teritorije 15<br />gradskih i prigradskih naselja Grada Novog Sada prikupljeni su plodovi pelenaste<br />ambrozije. Od ukupne količine prikupljenog semena pelenaste ambrozije, polovina je<br />odložena u hladnu komoru sa temperaturom od +4&ordm;C a drugi deo materijala je odložen<br />u komoru sa temperaturom od - 8&ordm;C da bi se simulirali zimski uslovi, odnosno kako bi<br />seme bilo izloženo jarovizaciji. Naklijavanje izdvojenog semena vr&scaron;eno je u klimakomori,<br />pod uslovima povoljnim za nicanje semena. Nakon 9, 14, 21 i 28 dana<br />ocenjivana je klijavost semena. Utvrđena je dobra klijavost semena pelenaste<br />ambrozije, koja je bila značajno veća kod stratifikovanog semena.<br />Na osnovu rezultata dobijenih tokom ispitivanja rasprostranjenosti i suzbijanja<br />korovsko-ruderalne alergene biljke Ambrosia artemisifolia L. u regiji gradova Novi<br />Sad, Zrenjanin i Ruma, izvedeni su sledeći zaključci: Obavljena proučavanja<br />rasprostranjenosti i suzbijanja korovsko-ruderalne alergene biljke Ambrosia<br />artemisifolia L. u 15 zona grada Novog Sada, 10 zona u Zrenjaninu i 7 u Rumi,<br />ukazuju na izuzetnu zastupljenost ove biljke. Na osnovu proučavanja rasprostranjenosti i praćenja feno-faza razvoja pelenaste ambrozije obavljeno je<br />mehaničko ko&scaron;enje ručnim ili motornim kosilicama. Imajući u vidu stalne napore u<br />pogledu za&scaron;tite životne sredine koja podrazumeva na prvom mestu pozitivan uticaj na<br />zdravlje ljudi, na gradskim lokacijama tretman herbicidom glifosat nije primenjen, već<br />samo u nenastanjenim zonama i na zapu&scaron;tenim poljoprivrednim povr&scaron;inama i<br />utrinama. Prilikom suzbijanja pelenaste ambrozije mehaničkim putem, istaknuto je da<br />je ko&scaron;enje potrebno obaviti 3-4 puta tokom jedne vegetacione sezone, usled relativno<br />brze regeneracije poko&scaron;enih biljaka. Hemijsko suzbijanje ambrozije primenom<br />herbicida glifosat, pokazalo se kao znatno efikasnije jer je za njeno suzbijanje bio<br />dovoljan uglavnom jedan tretman.</p> / <p>Ambrosia artemisiifolia L., an invasive weed-ruderal plant in recent years in<br />our country is a very big problem, not only for agriculture but also for the human<br />population, causing her severe pollen allergy and other health complications.<br />Recognizing the problems that it causes, all countries where ragweed is a large,<br />primarily health problem, invest huge efforts, allocate significant financial resources,<br />organized residents, schools, the military, the media, legislate, to limit its spread and<br />ensure its suppression, while our country does not yet have a serious approach to this<br />problem.<br />Since this is a plant that reproduces a generative (seed), &#39;&#39;seed bank&#39;&#39; research in some<br />soil profiles allow to forecast its occurrence at some sites, which greatly facilitates<br />the later contol of both mechanically and by herbicides. Soil samples for analysis of<br />seed reserves were taken with typical ruderal habitats, in Novi Sad, Zrenjanin and<br />Ruma. Since these are ruderal habitats, at all study sites, a relatively high number of<br />ragweed seeds apears. Our study is the first of this type that was conducted in the<br />Republic of Serbia.<br />These studies are of great scientific importance as it includes knowing of basic<br />biological properties of ragweed seeds, such as morphological characteristics, the<br />characteristics of germination, emergence and control methods.<br />For the purposes of testing seed germination A. artemisifolia in year 2007. samples<br />of ambrosia seeds were collected from 15 different localities in the territory of the<br />city and suburbs of Novi Sad. Collected seeds were splited on two halfs: one part was<br />delayed in the cold chamber with a temperature of +4 &deg; C and the second part of the<br />material is disposed in the chamber with a temperature of - 8 &deg; C to simulate winter<br />conditions, in purpose to achieve seed vernalization. Seed germination was<br />performed in air chamber under optimal conditions for seed germination. After 9, 14,<br />21 and 28 days seed germination was evaluated. Germination of stratified seeds was<br />significantly higher than germination of not stratified seeds.<br />Based on the obtained results of distribution and controll of weed-ruderal allergenic<br />plant Ambrosia artemisiifolia L. in the cities Novi Sad, Zrenjanin and Ruma, the<br />following conclusions were made: Results mapping and control of Ambrosia<br />artemisiifolia L. in 15 zones in the city of Novi Sad, 10 zones in Zrenjanin, and 7 in<br />Ruma, indicating significant presence of this plant. Based on the study of the<br />distribution and monitoring of ragweed growth stages, mechanical controll mesures<br />were performed manually, by trimmers or by tractor. Because of ongoing efforts to<br />protect the environment, in the urban locations herbicide treatment was not applied.<br />Glyphosate treatment was applied only in uninhabited areas, agricultural land and<br />wasteland. If ragweed is controlled mechanically, the cutting should be done 3-4<br />times per year due to the relatively rapid regeneration of plants. Chemical control of<br />ragweed (herbicide glyphosate), has proven much more effective. One treatment per<br />year was sufficient.</p>