• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 751
  • 339
  • 172
  • 67
  • 47
  • 44
  • 32
  • 15
  • 12
  • 12
  • 11
  • 10
  • 7
  • 6
  • 5
  • Tagged with
  • 1761
  • 1761
  • 344
  • 310
  • 304
  • 204
  • 184
  • 172
  • 155
  • 151
  • 143
  • 139
  • 132
  • 126
  • 125
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
781

Utvärdering av effektstyrningssystemet EnergiDirigent® ur ett miljöperspektiv

Lönn, Pernilla January 2007 (has links)
<p>Energy Director is a control and measuring system for energy consumption and is part of the product portfolio of E.ON AG for more efficient use of energy, offered to business customers. As of today, the system has only one parameter of control, namely power, and the objective of this essay has been to investigate whether other ones could be added. The emphasis is on the environmental perspective, which is why carbon dioxide has served as an example for this parameter in question.</p><p>Parallel with the study of Energy Director electricity on the margin, calculations of carbon dioxide equivalents and also the Swedish trade of electricity have all been highlighted. Results indicate that when reductions in energy are made it is endorsed to omit from electricity on the margin rather than some mean distributed electricity, under certain conditions, and in addition the calculations of the reductions should be modified regarding the efficiency of the power stations fuelled by lignite and bituminous coal. Sweden practices trade with the Nordic countries as well as Poland and Germany. Import and export represents essential factors in the discussion of electricity on the margin but they can nonetheless today be included in calculations concerning savings in emission of carbon dioxide.</p><p>The development of Energy Director is suggested to follow a model that includes the total emissions of carbon dioxide at each installation. Contributions are descended from local sources at the site, which are continuously measured, and from the energy that is obtained, where the equivalent amount of carbon dioxide has to be theoretically estimated. The total carbon dioxide limit control is then accomplished by means of controlling the obtained energy.</p> / <p>EnergiDirigent är ett styr- och mätsystem som ingår i E.ON:s produktsortiment för effektivare energianvändning. I dagsläget har systemet en styrparameter, uttagen effekt, och syftet med detta arbete har varit att undersöka om ytterligare styrparametrar kan infogas. Fokus för arbetet har varit att undersöka vilken potential EnergiDirigent har att bli miljövänlig. Styrparameter som tjänat som exempel för utredning har varit koldioxid.</p><p>Marginalel, det svenska elutbytet samt beräkning av koldioxidekvivalenter har behandlats parallellt med arbetet med EnergiDirigent. Arbetsgången har varit teoretisk med litteraturstudier, studiebesök och intervjuer. Resultat visar att vid en miljövärdering av el är det befogat att utgå ifrån marginalel vid besparingar, dock under vissa villkor, och att beräkningarna av besparingarna bör modifieras genom att verkningsgraden för kolkraftverk revideras. Sverige bedriver mycket handel med Norden samt Polen och Tyskland varför de har inkluderats i handelssystemet. Import och export är viktiga faktorer i behandling av marginalel men resurser saknas idag för att implementera faktorerna på ett adekvat sätt i besparingsuträkningar.</p><p>Utvecklingen av EnergiDirigent bör följa en modell som inkluderar det totala utsläppet av koldioxid vid varje installation. Bidrag till det totala utsläppet kommer ifrån lokala källor hos installationen, som hela tiden mäts, samt från den mängd energi som införskaffas, där motsvarande mängd koldioxid uppskattas teoretiskt. En styrgräns sätts på de totala utsläppen och följs sedan genom styrning på den inkommande energin.</p>
782

Energieffektivisering av sjöfarten : En studie om att implementera obligatoriska riktlinjer / Making shipping energy efficient : A study regarding implementing mandatory guidelines

Falk, David, Niklasson, Markus January 2014 (has links)
Vi lever i en värld av klimatförändringar där det ständigt söks efter lösningar för att minska utsläppen av växthusgaser. IMO har infört SEEMP:en med målet att reducera utsläppen från världshandelsflottan och därmed öka dess energieffektivitet. Med denna bakgrund har syftet varit att undersöka hur svenska tankrederier implementerat och tillämpat SEEMP:en samt kartlägga åsikter kring den. En kvalitativ metod har använts för att på djupet undersöka rederiernas tillvägagångssätt. Undersökningen omfattar fyra semistrukturerade intervjuer med totalt sex personer ifrån två rederier där både ombord- och landanställda finns representerade. Resultatet visade att rederierna implementerat SEEMP:en efter IMO:s riktlinjer, i samråd med sitt klassningssällskap, där rederierna också har försökt ta tillvara möjligheten att energieffektivisera sin organisation. Båda rederierna såg positivt på införandet av SEEMP:en och menade att den borde införts tidigare. Det framkommer dock faktorer som anses motverka SEEMP:ens fulla potential, bland annat att strukturen i branschen måste ändras för att kunna applicera SEEMP:en fullt ut. / We live in a world of climate change where finding a solution to reducing the emission of GHG is a continuous pursuit. To reduce the emission from global shipping IMO has adopted the SEEMP consequently making the shipping industry more energy efficient. With this in mind the purpose of this study has been to review the implementation and usage of the SEEMP among Swedish shipping companies trading oil. Furthermore, the views of the involved parties with regard to the SEEMP were also investigated. In order to deeply analyze the companies´ approach to the SEEMP a qualitative research method has been used. The study consists of four semi-structured interviews with sex persons from two shipping companies including both onshore and ship-based personnel. The result shows that the implementation has been carried out in consultation with their own classification societies and with the IMO guidelines in mind. They have also tried to take the opportunity to make their organization more energy efficient. Both companies welcomed the adoption of the SEEMP and were of the opinion that it shouldhave been introduced at an earlier stage. However, some barriers to the SEEMP have been found, for example the operational structure of the shipping industry.
783

Energy performance regulations and methodologies of energy saving in office buildings in southern Europe

Tsave, A. January 2009 (has links)
The Directive 2002/91/EC of the European Parliament and Council on energy performance of buildings entered into force on 4th January 2003, setting the minimum requirements of energy performance. All Member States had to incorporate the requirements of the new directive in national legislation by January 2006 and build up relevant systems and measures to transpose and implement these requirements. The stage of Directive’s implementation in the countries of Southern Europe is reported because of the similar climatic conditions and the geographical location for a future enforcement in Greece, as the building code in Greece is still under development. As energy use in buildings accounts for about 40% of the final energy demand in the European Union, the application of building standards can achieve a reduction in electric energy consumption and therefore an increase in energy performance of buildings. A record of the electric energy consumption of office buildings in the four Prefectures of Crete is implemented aiming at a future energy saving, which may be obtained by either through increased efficiency or by reducing electric energy consumption.
784

Energieffektivisering av byggnad med enkla medel : en fallstudie på Hofors mödravårdscentral

Andersson, Niklas January 2016 (has links)
I centrala Hofors ligger vårdcentralen som ingår i Hoforshus ABs byggnadsbestånd, byggnaden i sig är uppdelad i en huvudbyggnad och en mindre del där BVC och mödravårdsverksamheten återfinns. Byggnaderna är sammanbundna med en korridor som huvudsakligen är inglasad. Företaget var intresserat av att kartlägga byggnadens energianvändning eftersom denna föreföll relativt hög, dessutom hade brukarna i byggnaden uttryckt sitt missnöje med inneklimatet under såväl sommar- som vintertid. På grund av den verksamheten i byggnaden var lösningar som inte stör denna av högsta intresse. Studien som genomförts har haft främsta fokus på byggnadens klimatskal och fram för allt på glasgångens inverkan på den övriga byggnaden. Det kan förutsättas att den höga andelen glas i den här delen av byggnaden påverkar dess inneklimat negativt medtanke på de låga U-värdet hos glas och den solvärmelast som detta ger under sommartid då värmetillskottet inte är önskat. En litteraturstudie för att undersöka hur människor upplever inneklimatet samt hur en tillförlitlig simuleringsmodell för en byggnad har genomförts. Studien resulterade i en förståelse för hur inneklimatet upplevs och kvantifieras samt en förståelse för vad som är viktigt vid insamling av data till en simuleringsmodell. Med tanke på hur indata skall hämtas enligt litteraturstudien har så mycket data som möjligt mätts upp via undersökningar och egna observationer, ritningar har undersökts och deras validitet har undersökts genom uppmätning av byggnaden, blower-door har genomförts samt temperatur- och relativånghaltloggning. Momentanvärden. på FTX-systemet för att beräknas dess verkningsgrad. Linjära köldbryggor har undersökts med finitelementmetod i programmet Comsol multiphysics 3,5. För validering av simuleringsmodellen har uppmätta energiförbrukningen använts och jämförts med simuleringens resultat. Simuleringarna är genomförda i BV2. Resultatet av studien visar som tidigare förväntat på glasgångens negativa inverkan på byggnadens inneklimat temperaturen loggades mellan den 12 april och 9 maj 2016 högsta temperaturen var 30°C och lägsta 15°C vilket är en större spridning jämfört med övriga utrymmen där temperaturen loggats. Simuleringarna som genomfördes av glasgången visar att denna förbrukar mellan 5000-5500 kWh med bruksarean 13,5 m2. Slutligen resulterade studien i rekommenderade åtgärder för byggnaden som innefattar tilläggsisolering av vindsbjälklag, utbyte av ett mindre väggparti, sänkning av temperaturen med 1°C samt en del underhållsåtgärder för att förbättra inneklimatet. Åtgärderna antas vara möjliga att genomföra utan att verksamheten störs. Föreslagna åtgärder förefaller också relativt lönsamma enligt pay-off metoden. / In the central parts of Hofors a healthcenter is located which is included in Hoforshus AB's building stock, the building itself is divided into a main building and a smaller one in which the child health center and maternity care is located. The buildings are connected by a corridor substantially glazed. Now they are interested in maping the building's energyusage as this is relatively high, in addition, the users of the building had been dissatisfied with the indoor climate in both summer and winter. Because of the healtcare activities the owners were most interested in finding solutions that would not interfere with it. The study conducted has had a primary focus on the building envelope and above all on the glazed corridor’s impact on the rest of the building. One can assume that the high proportion of glass in this part of the building affects the indoor climate negatively keeping in mind the low U-value of the glass and the solar heat load, this gives during the summer when heat gain is not desired. A literature study to investigate how people perceive the climate as well as how to make a reliable simulation model of a building has been completed. The study resulted in an understanding of how the indoor climate is perceived and quantified, and also in an understanding of what is important in the collection of data for the simulation model. Keeping in mind how data should be collected according to the literature reviwe- have as much data as possible measured through surveys and own observations, blueprints have been studied and their validity has been investigated by measuring the building, blower door has been performed and temperature- and relative humidityloggning. Instantaneous values of the FTX system was made to calculate its efficiency. Linear thermal bridges have been investigated by finite element method in the program COMSOL Multiphysics 3.5. For validation of the simulated model the results of it were compared with the acutal measured energyconsumption of the building. The simulations were performed in BV2. The results of the study show, as expected, the glazed corridor’s negative impact on the building's indoor climate. Temperature was logged between 160412-160509 highest temperature was 30 ° C and minimum 15 ° C, which is more widespread than in other areas where the temperature was logged. The simulations that were performed on the glazed corridor shows that it consumes between 5000-5500 kWh on the area of 13.5 m2. Finally the study resulted in recommendations for the building that includes additional insulation of the attic, replacement of a smaller wall section, lowering the temperature by 1 ° C, as well as some maintenance measures to improve the indoor climate. The measures are believed to be possible to implement without significant interference with the health care acitivities. In addition the proposed measures seem profitable according to the pay of method.
785

Energieffektivisering av byggnader med kulturhistoriskt värde / Energy efficiency of buildings with historical value

Jakobsson, Joakim, Johansson, Lucas January 2016 (has links)
Syfte: Syftet med arbetet är att bidra till att fastighetsägare fortsatt ska kunna förvalta, driva och bruka gamla kulturhistoriskt viktiga hus även i framtiden. Metod: De metoder som valts för att uppnå målet är dokumentanalys, litteraturstudier och fallstudie. Resultat: Kulturhistoriskt viktiga byggnader behöver energieffektiviseras för att de ska kunna hållas i bruk och existera. Det går att genomföra energieffektiviserande åtgärder utan att skada byggnadens kulturvärde. Åtgärder som fönsterbyte, tilläggsisolering och byte av ventilationssystem bör väljas beroende på husets karaktär. Tilläggsisolering och fönsterbyte är effektiva åtgärder för att minska energiförbrukningen av gamla kulturhistoriskt viktiga byggnader, men riskerar ofta att förvanska byggnadens karaktär. Ventilationssystemsbyte kan innebära mindre ändringar av byggnaden men är en relativt dyr investering. Konsekvenser: Ändringar i en befintlig byggnad kommer dock alltid att påverka dess konstruktion, men det betyder inte att byggnadens kulturhistoriska värde förvanskas. Begränsningar: Beräkningar kommer endast att utföras för ett referensobjekt, stadsbibliotek i Tidaholm. Det beräknade resultatet kommer vara specifikt för denna byggnad, eftersom resultatet varierar med byggnaders olika egenskaper. Däremot kan lösningarna tillämpas på flera objekt. Det finns flera olika energieffektiviserande åtgärder men i denna rapport utreds tilläggsisolering, fönsterbyte och ventilationsbyte. Nyckelord: Energieffektivisering, kulturhistoriskt viktiga byggnader, värmeväxlare, Boverkets byggregler, ventilation. / Purpose: The purpose of the work is to help municipalities continue to manage, operate and use old historic houses in the future. Method: The methods chosen to achieve the objective is document analysis, literature studies and case study. Findings: Culture heritage buildings needs to get more energy efficient, so they can be kept in use and existence. It is possible to implement energy efficiency measures without damaging the building's cultural value. Measures like window replacement, insulation and replacement of ventilation systems should be selected depending on the character of the house. Insulation and window replacement are effective measures to reduce the energy consumption of old historically important buildings, but often risk distorting the character of the building. Ventilation system replacement can involve minor changes to the building but is a relatively expensive investment. Implications: Changes in an existing building will always affect its construction, but it does not mean that the building's heritage value is distorted. Limitations: Calculations will only be performed for a reference object, library in Tidaholm. The calculated result will be specific for this building, since the outcome varies with buildings and their different characteristics. However, the solutions can be applied to multiple objects. There are several energy efficiency measures, but this report will only involve insulation, window replacement and ventilation changes. Keywords: Energy efficiency, historically important buildings, heat exchanger, building regulations, ventilation.
786

Rumsutformningens inverkan på dagsljuset i kontorslokaler / The impact of room configuration regarding daylight harvesting in offices

Holmström, Andreas, Fyhr, Sandra January 2016 (has links)
Public buildings are considered to be the most power consuming buildings in the world. To reduce power consumption earlier studies propose greater use of natural daylight to illuminate surroundings, hallways and areas where to preform common work tasks and where artificial lighting is only used for the actual work space and places where higher light levels are required. In office buildings with available daylight, it has been shown that people have a greater general well-being, improved health, reduced absenteeism and increased productivity. The purpose of this study is to investigate how different room configurations can increase the amount of daylight in offices. The essay is based on an experimental study in the form of a questionnaire in which participants have evaluated and documented their perceptions of the visual properties regarding daylight. The evaluation has been carried out with scale models of different room configurations, but with the same window size and window positions. The results show that a room configuration with embrasures provides the most effective daylight harvesting. Embrasures contribute with maximum visibility, brightness and provide maximum light scattering. Room configurations with rounded corners have proven to give the most even light ratio between the light and dark areas of a room where the light is also spread most evenly along the walls. According to an evaluation of the visual properties of daylight, a room with rounded corners is perceived to be the most comfortable room and provide the softest and gentlest light impression. The study is limited to evaluate the amount of daylight and the visual properties of daylight in large office spaces designed based on energy-efficient passive houses with thick facade walls. / Offentliga byggnader räknas som de byggnader som har störst energianvändning i världen. För att sänka energianvändningen föreslås ökad användning av dagsljus för att lysa upp omgivning, korridorer och platser för allmänna arbetsuppgifter och där den artificiella belysningen endast används vid arbetsytor och platser där högre ljusnivå krävs. I kontorsbyggnader med tillgängligt dagsljusinsläpp har det också visats att människor har ett ökat allmänt välbefinnande, bättre hälsa, minskad frånvaro och ökad produktivitet. Syftet med studien är att undersöka hur olika rumsutformningar kan bidra till ökat tillvaratagande av dagsljus i kontorslokaler. Undersökningen bygger på en experimentell studie i form av en enkätundersökning där testpersoner har utvärderat och dokumenterat sina uppfattningar kring dagsljusets visuella egenskaper. Utvärderingen har genomförts i skalmodeller med olika rumsutformningar men samma fönstermått och fönsterplacering. Resultaten har visat att rumsutformningar med fönstersmygar ger det mest effektiva dagsljusinsläppet i en kontorslokal. Smygar bidrar med högst synbarhet, ljushet och uppfattas ge mest ljusspridning. Rumsutformningar med rundade hörn har enligt dagsljusmätningar visat ge jämnast ljusförhållande mellan de ljusa och mörka delarna av ett rum där ljuset också sprids jämnast efter väggarna. Enligt en utvärdering av dagsljusets visuella egenskaper anses ett rum med runda hörn mest behaglig att vistas i samt ger det mjukaste och mildaste ljusintrycket. Undersökningen är avgränsad till att utvärdera dagsljusmängd och dagsljusets visuella egenskaper i stora kontorslokaler utformade enligt krav för energieffektiva passivhus med djupa fasadväggar.
787

Odnos energetske efikasnosti i pouzdanosti u bežičnim senzorskim mrežama / Energy-Efficiency and Reliability Trade-Off in Wireless Sensor Networks

Zogović Nikola 24 October 2013 (has links)
<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>
788

Algoritmi za dodelu zadataka izvršiocima u bežičnim mrežama mikrokontrolerskih senzorskih uređaja i autonomnih robota / Algorithms for task assignment in wireless networks of microcontroller sensor nodes and autonomous robots

Lukić Milan 02 November 2015 (has links)
<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>
789

Povišenje energetske efikasnosti programabilnog pneumatskog manipulatora u kontaktnim zadacima / Increasing energy efficiency of programmable pneumatic manipulator in contact tasks

Šulc Jovan 23 September 2016 (has links)
<p>Dat je pregled mogućnosti za povišenje energetske efikasnosti<br />pneumatskog programabilnog manipulatora primenjenog u kontaktnim<br />zadacima. Projektovano je i realizovano ispitno postrojenje. Posebno<br />je ukazano na mogućnosti projektovanja različitih upravljačkih<br />sistema. Razvijeni su primeri PWM i proporcionalnog upravljanja.<br />Ispitana su predložena rešenja iz različitih aspekata energetske<br />efikasnosti i kvaliteta praćenja trajektorije pri korišćenju<br />različitih vrsta materijala i alata. Izvučeni su potrebni zaključci.</p> / <p>This paper contains an overview of possibilities for increasing the energy<br />efficiency of programmable pneumatic manipulator in contact tasks.<br />Experimental station is designed and realized as a testbed. Especially, point<br />is on possibilities of designing of new control systems. Examples of PWM<br />and proportional control are developed. Proposed solutions are examined<br />from aspects of energy efficiency and quality of trajectory tracking, by using<br />various types of materials and tools. Necessary conclusions are drawn.</p>
790

Adaptive technique for energy management in wireless sensor networks : development, simulation and evaluation of adaptive techniques for energy efficient routing protocols applied to cluster based wireless sensor networks

Ghneimat, Ahmed Ali Hassan January 2012 (has links)
Recently, wireless sensor networks have become one of the most exciting areas for research and development. However, sensor nodes are battery operated, thus the sensor's ability to perform its assigned tasks is limited by its battery capacity; therefore, energy efficiency is considered to be a key issue in designing WSN applications. Clustering has emerged as a useful mechanism for trade-off between certain design goal conflicts; the network life time, and the amount of data obtained. However, different sources of energy waste still exist. Furthermore, in such dynamic environments, different data rate requirements emerge due to the current network status, thus adapting a response to the changing network is essential, rather than following the same principle during the network's lifespan. This thesis presents dynamic techniques to adapt to network changes, through which the limited critical energy source can be wisely managed so that the WSN application can achieve its intended design goals. Two approaches have been taken to decreasing the energy use. The first approach is to develop two dynamic round time controllers, called the minimum round time controller MIN-RC and the variable round time controller VAR-RC, whereas the second approach improves intra-cluster communication using a Co-Cluster head; both approaches show better energy utilisation compared to traditional protocols. A third approach has been to develop a general hybrid protocol H-RC that can adapt different applications requirements; it can also tolerate different data rate requirements for the same application during the system's lifetime.

Page generated in 0.0637 seconds