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  • 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.
1

Accommodating a High Penetration of Plug-in Electric Vehicles in Distribution Networks

Shaaban, Mostafa January 2014 (has links)
The last few decades have seen growing concern about climate change caused by global warming, and it now seems that the very future of humanity depends on saving the environment. With recognition of CO2 emissions as the primary cause of global warming, their reduction has become critically important. An effective method of achieving this goal is to focus on the sectors that represent the greatest contribution to these emissions: electricity generation and transportation. For these reasons, the goal of the work presented in this thesis was to address the challenges associated with the accommodation of a high penetration of plug-in electric vehicles (PEVs) in combination with renewable energy sources. Every utility must consider how to manage the challenges created by PEVs. The current structure of distribution systems is capable of accommodating low PEV penetration; however, high penetration (20 % to 60 %) is expected over the next decades due to the accelerated growth in both the PEV market and emission reduction plans. The energy consumed by such a high penetration of PEVs is expected to add considerable loading on distribution networks, with consequences such as thermal overloading, higher losses, and equipment degradation. A further consideration is that renewable energy resources, which are neither exhaustible nor polluting, currently offer the only clean-energy option and should thus be utilized in place of conventional sources in order to supply the additional transportation-related demand. Otherwise, PEV technology would merely transfer emissions from the transportation sector to the electricity generation sector. As a means of facilitating the accommodation of high PEV penetration, this thesis proposes methodologies focused on two main themes: uncontrolled and coordinated charging. For uncontrolled charging, which represents current grid conditions, the proposal is to utilize dispatchable and renewable distributed generation (DG) units to address the high PEV penetration in a way that would not be counterproductive. This objective is achieved through three main steps. First, the benefits of allocating renewable DG in distribution systems are investigated, with different methodologies developed for their evaluation. The benefits are defined as the deferral of system upgrade investments, the reduction in the energy losses, and the reliability improvement. The research also includes a proposal for applying the developed methodologies for an assessment of the benefits of renewable DG in a planning approach for the optimal allocation of the DG units. The second step involves the development of a novel probabilistic energy consumption model for uncontrolled PEV charging, which includes consideration of the drivers’ behaviors and ambient temperature effect associated with vehicle usage. The final step integrates the approaches and models developed in the previous two steps, where a long-term dynamic planning approach is developed for the optimal allocation of renewable and dispatchable DG units in order to accommodate the rising penetration of PEV uncontrolled charging. The proposed planning approach is multi-objective and includes consideration of system emissions and costs. The second theme addressed in this thesis is coordinated PEV charging, which is dependent on the ongoing development of a smart grid communication infrastructure, in which vehicle-grid communication is feasible via appropriate communication pathways. This part of the work led to the development of a proposed coordinated charging architecture that can efficiently improve the performance of the real-time coordinating PEV charging in the smart grid. The architecture is comprised of two novel units: a prediction unit and an optimization unit. The prediction unit provides an accurate forecast of future PEV power demand, and the optimization unit generates optimal coordinated charging/discharging decisions that maximize service reliability, minimize operating costs, and satisfy system constraints.
2

Zhodnocení návaznosti územního plánu a komplexní pozemkové úpravy ve zvolené lokalitě / The Evaluation of Continuity in Spatial Planning and Comprehensive Landscaping in Selected Location

MLÁDKOVÁ, Tereza January 2014 (has links)
This diploma thesis evaluates continuity of two different and stand-alone documents that fundamentally affect the character of the area. This continuity of spatial plan and comprehensive land adjustment is compared in the selected area of the cadastral territory of municipality Libějice. The object of my research were public works and public interest measurements in the spatial planning and the plan of common facilities in the comprehensive landscaping, where in the case of these two documents lead to consensus. The results are presented in both text and graphical form, processed by a geographic information system ArcGIS 10th.
3

Effektivisering av kommunikation mellan arbetsledning och yrkesgrupper på byggarbetsplatsen / Streamlining of communication between work management and professional groups in the construction site

Mohammed, Yousef, Bakro, Abdulrahman January 2020 (has links)
Många aktörer deltar ofta i olika byggprojekt. Deltagarna kommer från olika yrkesområden vilket gör att var och en har sitt egna synsätt samt metoder i relation till arbetet. Detta innebär att det ligger en stor vikt på kommunikation eftersom att man behöver samordna och planera projektets aktiviteter på ett effektivt sätt för att nå ett resultat. Kommunikation innebär i första hand information som antingen överförs eller mottages mellan individer. Information på byggarbetsplatsen överförs muntlig via mänskligt språk eller digitalt via digitala verktyg. Via båda sätt är det viktig att information är tydlig för att kunna överföra det på ett rätt sätt. Examensarbetets syfte är att undersöka hur kan kommunikation och informationsflöde mellan arbetsledning och yrkesgrupper effektiviseras för att uppnå effektiv produktivitet på byggarbetsplatsen. Målet med examensarbetet har varit att få en övergripande bild kring kommunikationsprocessen i dagsläget på de undersökta byggarbetsplatserna. Delmålet har varit att undersöka hur kommunikationen fungerar mellan yrkesarbetarna och arbetsledningen på byggarbetsplatsen. Det andra delmålet har varit att ta reda på hur BIM som arbetssätt kan förbättra kommunikationen under produktion. Dessutom var delmålet att studera hur fungerar kommunikation på byggarbetsplatsen vid användning av visuell planering produktion (VPP) och vilka eventuella störningar som inträffar inom detta område. Studien är baserad på en litteraturstudie för att ta reda på hur kommunikation och informationsflöde fungerar på byggarbetsplatsen och även dels för att undersöka hur kommunikation kan påverkar visuella planeringsmetoder VPP. För att få ett övergripande resultat har det använts kvalitativa och kvantitativa metoder samt en observationsstudie. Den kvalitativa studien består av semistrukturerade intervjuer med tjänstemän i arbetsledningen och erfarna yrkesarbetare. Den kvantitativa studien består av en enkätundersökning riktad mot 48 yrkesarbetare och 9 tjänstemän inom fem olika arbetsplatser. Resultatet visar att kommunikationen mellan arbetsledningen och olika yrkesgrupper fungerar bra men att det skulle kunna utvecklas och bli ännu bättre. Kommunikation påverkas av två huvudaspekter, kvalitet av levererade information alltså bygghandlingar och informations överföringssätt mellan individer, om det är digitalt eller icke digitalt sätt. Den mänskliga faktorn som definieras med delaktighet, engagemang, individens kunskap, språk och okoncentration påverkar kommunikation betydligt och framgår mest under möten och arbetsberedningar. Dessutom underlättar den digitala faktorn spridning av information mellan yrkesarbetare och tjänstemän genom användning av digitala verktyg och som betyder i sin tur lättare kommunikation. VPP är ett effektiv informations överföringssätt på byggarbetsplatsen. Det underlättar informationsspridning och kommunikationsmöjligheter genom att synliggöra planering, visualisera gemensamma mål och skapa större engagemang bland yrkesarbetare. Förbättringsmöjligheter som rekommenderas för att uppnå effektivare kommunikation, är att byggföretag fokuserar mer på arbetsklimat, involverar yrkesarbetare ännu mer under projekteringsoch produktionsfas samt använder BIMs digitala verktyg såsom BIM 360 ytterligare bland yrkesgrupper för att minimera informationsförluster. Det krävs också bättre kunskapsnivå och kompetens hos olika yrkesgrupper. Det behövs fler arbetsberedningar och att involvera underentreprenörer i dem. Slutligen att tillhandahålla lämpliga förutsättningar för att underlätta kommunikation mellan olika konstruktörer under projektering för att säkerställa en bättre kvalitet på bygghandlingar. / In construction projects, many individuals from different occupational fields often participate, each with their own approach and specialty. Based on this, the importance of communication and coordination and planning to the project's mission will have arisen. Communication primarily means the information transmitted, whether it is transmitted between people or digitally through digital tools and how clear this information is to the recipient. The thesis aims to investigate how communication and information flow can affect the productivity of work management and professional groups in the construction site. The aim of this paper is to get an overall picture of the communication process at present in the surveyed construction sites. The partial aim is to investigate how communication at the construction sites works when using visual planning production (VPP) as a planning method and to overview any disturbance that occurs in this area. The second partial aim is to identify the most important factors that are missing or the ones which can be improved during the present time. Using this method will lead us to improved communication at the construction site. The study was based on academic studies to understand how communication and information flow work at the construction site, and partly who this method helps to investigate how communication can influence the planning methodology VPP. To obtain real and comprehensive results, both qualitative and quantitative studies have been conducted. The qualitative study consists of semi-structured interviews with senior executives and experienced professional workers. The quantitative study consists of a survey of 48 professional workers and 9 employees within 5 different workplaces. The results show that communication between management and various professional groups works well, but that it could be developed and become even better. Communication is affected by two main aspects, the quality of delivered information which is construction documents and the method of information transfer between individuals, whether it is digital or non-digital. The human factor, which is defined by participation, commitment, the individual's knowledge, language and lack of concentration, significantly affects communication and is most evident during meetings and work preparations. In addition, the digital factor facilitates the dissemination of information between professionals and white-collar workers through the use of digital tools, which in turn means easier communication. VPP is an efficient information transmission method on the construction site. It facilitates the dissemination of information and communication opportunities by making planning visible, visualizing common goals and creating greater engagement among professionals. The most prioritized improvement opportunities that we can recommend to achieve more effective communication are that construction companies should focus more on the work climate, involve professional workers more during the design and production phase, use more BIM digital tools such as BIM 360 among professional working groups to minimize information loss, build better knowledge level and competence. Professional working groups should hold more preparation meetings with the importance of involving subcontractors in it and also provide appropriate conditions for facilitating communication between different designers during design to ensure a better quality of construction documents.
4

Description and Evaluation of a Novel Approach for Offline Coordination of Routing Autonomous Free-Ranging Vehicles in Intralogistics Transportation Systems

Reith, Karl-Benedikt 03 May 2024 (has links)
Driven by recent technical advances, vehicle-based transportation systems in intralogistics are currently shifting from automated guided vehicles (AGVs) to autonomous mobile robots (AMRs). Unlike AGVs, AMRs are not bound to a physical or virtual track and autonomously determine their movements. While the increase in freedom for routing leads to improvements in terms of system flexibility and scalability, it also poses new challenges in terms of coordination and thus the high-performance routing behavior of an entire fleet. Accepted and widely used algorithms in the AGV field are often barely applicable to large fleets of free-ranging AMRs, while typical algorithms from the field of mobile robotics usually focus on different objectives. This thesis presents a novel concept for determining global routes, the so-called lanemap, that enables the synchronized movements of multiple free-ranging vehicles in arbitrary layouts without increasing calculation effort during online operations. The basic idea consists in creating a lanemap offline that provides the AMRs with a set of suggested global lanes from various starting positions to different destinations. On the one hand, the application of a lanemap lowers each AMRs’ individual degree of freedom. However, coordinating lanes sensibly beforehand enables short travel distances as well as a low probability of routing conflicts, which improves the performance of the entire AMR fleet on the other hand. Since the lanemap only provides an offline calculated global route as suggestion, the concept can be combined with any established online approach, such as a local conflict avoidance/resolution approach, or with in-depth coordination of all vehicle movements. This thesis presents a theoretical mathematical model and a practically applicable heuristic approach for the creation of a lanemap. As proof of concept, simulation experiments show that the heuristic is generally capable of creating lanemaps for all different kinds of layouts. Furthermore, the concept allows for the determination of customized routes for a specific fleet size and an anticipated transportation demand. Therefore, once system requirements are known, a beneficial set of lanemaps for typical constellations can be calculated in advance and integrated into routing as needed.

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