Hästens Beds is a Swedish luxury bed manufacturer, located in Köping, Sweden. They have a strong global presence, with Europe being the most mature and proven market. European retailers, called Hästens Partners, are serviced from the central warehouse in Borås which also handles all non-European export to Hästens’ other warehouse facilities in Hong Kong and the United States. As a part of Hästens’ planned growth journey, they are interested in reevaluating their European distribution network from a total cost and delivery service perspective. Hence, the purpose of this master’s thesis is to evaluate alternate distribution network designs in Europe for Hästens to reduce total logistics costs without impairing the delivery service level.  Extensive literature studies and initial interviews were conducted to understand both the theoretical field and the Hästens’ case-specific context. Based on this, three main research questions and a corresponding method resulted in a three-step approach to answer the purpose of the study.  In order to generate network structures and then analyze them, it was first necessary to determine the factors that should be included. Cost functions were created based on curve fitting, based on identified cost drivers for the included cost parameters of warehousing, transportation, and inventory carrying. Furthermore, the customer order lead time was concluded to be very generous. This had the consequence of the distribution lead time not putting any constraints on the network design. Lastly, access to transportation infrastructure, especially a port for handling the non-European export, and the general cost disparity between neighboring regions were concluded to be other important factors for the specific case of Hästens.  Center of gravity analyses based on the identified cost driver for outbound costs, m3-km, were then used to generate 13 candidate warehouse locations. In some cases, these locations were altered to better align with the identified important factors of good access to transportation infrastructure and cost disparity. The most strategically viable combinations of the number and echelons of warehouses could be limited to three combinations, all consisting of a single echelon with one, two, or three warehouses respectively. Therefore, three network optimization scenarios were created, minimizing the total cost of inbound and outbound transportation, which led to the generated network alternatives.  Finally, the total logistics costs were calculated and analyzed for the three alternative structures and a model replica of the current structure by utilizing the cost functions for each included cost parameter. The alternatives were also discussed based on delivery service theory and quantified with regard to distances to Partners. After applying sensitivity analysis and discussing the results’ implications for Hästens, Alternative 2* was formed with warehouses in Borås and Rotterdam. All the alternatives’ total logistics costs and average distances to Partners are quantified below.  [TABLE] As can be seen, the cost savings from Alternative 1 compared with the current network are marginal, and the costs of Alternative 2 and 2* are highly similar. Further, preliminary analysis showed that Alternative 2* would not be economically profitable until at least a 500% increase in European outbound transportation volumes. The conclusion that could be drawn from this was that Hästens is not yet suited to scale up its European distribution network to operate more than one warehouse. However, when future sales volumes allow for it, a European distribution center in Rotterdam could be profitable and provide European customers with greater delivery service.

Yes / In this paper, a stochastic method for active distribution networks planning within a distribution market environment considering multi-configuration of wind turbines is proposed. Multi-configuration multi-scenario market-based optimal power flow is used to maximize the social welfare considering uncertainties related to wind speed and load demand and different operational status of wind turbines (multiple-wind turbine configurations). Scenario-based approach is used to model the abovementioned uncertainties. The method evaluates the impact of multiple-wind turbine configurations and active network management schemes on the amount of wind power that can be injected into the grid, the distribution locational marginal prices throughout the network and on the social welfare. The effectiveness of the proposed method is demonstrated with 16-bus UK generic distribution system. It was shown that multi-wind turbine configurations under active network management schemes, including coordinated voltage control and adaptive power factor control, can increase the amount of wind power that can be injected into the grid; therefore, the distribution locational marginal prices reduce throughout the network significantly.

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Yes / The complexities surrounding the supply chain logistics for perishable commodities within Bangladesh are extensive. Poor infrastructure, fragmented transportation and corruption compound the operational complexities within this emerging market. This case study analyses many of the day-to-day operational challenges and tensions inherent within Micro-Small-Medium Enterprises (MSMEs) forming the backbone of the Bangladesh socio-economic structure. The drive for transition toward greater levels of sustainability and corporate responsibility is problematic, affecting many levels within an extended and fragmented supply chain. The selected case study highlights the “lived in” geographical, environmental, economic and cultural factors that impact the ability of emerging market enterprises to remain profitable within emergency scenarios whilst transitioning toward a more sustainable model. This study, whilst detailing many of the tensions and critical issues facing MSMEs, highlights the benefits of direct Government intervention, criticality of a leaner and more efficient supply chain and reassessment of financial incentives to drive the transition to a more efficient and sustainable economy.

No / This chapter proposes a novel method for the operation of active distribution networks within a distribution market environment taking into account multi-configuration of wind turbines. Multi-configuration multi-scenario market-based optimal power flow is used to maximise the social welfare considering uncertainties related to wind speed and load demand. Scenario based approach is used to model the uncertainties. The method assesses the impact of multiple-wind turbine configurations on the amount of wind power that can be injected into the grid and the distribution locational marginal prices throughout the network. The effectiveness of the proposed method is demonstrated with 16-bus UK generic distribution system.

L’évolution de la consommation électrique est un point clé pour les choix à venir, tant pour les moyens de production d’électricité, que pour le dimensionnement du réseau à toutes ses échelles. Aujourd’hui, ce sont majoritairement des modèles statistiques basés sur les consommations passées et des tendances démographiques ou économétriques qui permettent de prédire cette consommation. Dans le contexte de la transition énergétique, des changements importants sont en cours et à venir, et la consommation future ne sera certainement pas une continuation des tendances passées. Modéliser ces changements nécessite une modélisation fine de type bottom-up de chaque contributeur de la consommation électrique. Ce type de modèle présente des challenges de modélisation, car il nécessite un grand nombre de paramètres d’entrée qui peuvent difficilement être renseignés de façon réaliste à grande échelle. En même temps, les données et informations de tout type n’ont jamais été autant disponibles. Cela représente à la fois un atout pour la modélisation, mais aussi une difficulté importante notamment à cause de l’hétérogénéité des données. Dans ce contexte, cette thèse présente une démarche de construction d’un simulateur de consommation électrique bottom-up capable de simuler différentes alternatives énergétiques à l’échelle de la France. Un travail de recensement, de classification et d’association des bases de données pour expliquer la consommation électrique a d’abord été mené. Ensuite, le modèle de consommation électrique a été présenté ; il a été validé et calibré sur une grande quantité de mesures de consommation électrique des départs HTA fournie par Enedis. Ce modèle a enfin pu être utilisé pour simuler différentes alternatives énergétiques afin d’aider au dimensionnement du réseau de distribution. / Future trend of electricity demand is a key point for sizing both the electricity network and the power plants. In order to forecast future electricity demand, current models mostly use statistical approaches based on past demand measurements and on demographic and economic trends. Because of current context of energy transition which comes along with important changes, future electricity demand is not expected to be similar to past trends. Modeling these changes requires a bottom-up modeling of each contributor to electricity demand. This kind of model is challenging because of the large number of input data required. At the same time, data and information are more and more available. Such availability can be considered both as an asset for modeling and as an important issue because of data heterogeneity. In this context, this dissertation offers an approach to build a bottom-up load curve simulator which enables to simulate prospective scenarii at the scale of France country. Firstly, an assessment, classification, and matching of the large databases explaining the electricity demand have been performed. Then, the electricity demand model has been presented. It has been validated and calibrated on Enedis’ large volumes of electricity demand measurements of medium voltage feeders. Finally, this model has been used to simulate several prospective scenarii in order to improve the electricity distribution network sizing.

A qualidade da água de abastecimento é de vital importância à saúde da população dos núcleos urbanos do mundo todo. Por essa razão, muitas pesquisas enfocam esse tema. Além disso, os ataques terroristas recentes ocorridos nos Estados Unidos e Europa, vêm fomentando a antiga preocupação relativa a possíveis injeções de contaminantes em redes de distribuição de água para abastecimento, evidenciando a importância da efetiva vigilância de tais sistemas. O presente trabalho investiga a rede de monitoramento ótima para detecção de injeções intencionais de poluentes e/ou contaminantes em concentrações e/ou quantidades suficientes para que se propaguem nas direções do fluxo da água no interior das redes, do ponto de vista de objetivos múltiplos. A metodologia aqui apresentada representa uma extensão de propostas anteriores e é demonstrada ilustrativamente, através de redes já utilizadas na literatura. Com base no conceito da rede auxiliar proposto por Kessler et al. (1998), propõe-se o emprego de algoritmos genéticos multiobjetivo para considerar os níveis de serviço em termos do volume consumido, do tempo e da extensão da rede atingida antes da detecção. São criadas matrizes de poluição para os níveis de serviço considerados e, então, o algoritmo genético multiobjetivo SPEA é aplicado para identificar as soluções não-dominadas, em conformidade com o conceito de otimalidade de Pareto. Os resultados demonstram o potencial do método proposto em identificar tais soluções / The water supply quality is very important to the healthy of urban nucleus populations around the world. This is the reason why many researches focus on such theme. Besides this, recent terrorist attacks occurred in USA and Europe, have incited the old apprehension related to possible deliberate intrusions of contaminants into the water supply networks, making evident the importance of the effective vigilance of such systems. This work investigates the optimal monitoring network for detection of deliberate intrusions of pollutes and/or contaminants at concentrations and/or quantities enough for propagation inside the networks, on the point of view of multiple objectives. The method here proposed represents an extension to earlier proposals and is demonstrated with the support of networks from literature. Based on the concept of auxiliary network proposed by Kessler et al. (1998), a multiobjective genetic algorithm is used in order to consider the levels of service in terms of the consumed volume, time period and length of the network reached before detection. Pollution matrixes are built for the levels of service considered and the multiobjective genetic algorithm SPEA applied in the identification of the non-dominated solutions, according to the Paretto optimality concept. The results demonstrate the potential of the method in the identification of such solutions

Over the past few decades, wireless local area networks (WLANs) have been widely deployed for data communication in indoor environments such as offices, houses, and airports. In order to fairly and efficiently use the unlicensed frequency band that Wi-Fi devices share, the devices follow a set of channel access rules, which is called a wireless medium access control (MAC) protocol. It is known that wireless devices following the 802.11 standard MAC protocol, i.e. the distributed coordination function (DCF), suffer from packet collisions when multiple nodes simultaneously transmit. This significantly degrades the throughput performance. Recently, several studies have reported access techniques to reduce the number of packet collisions and to achieve a collision free WLAN. Although these studies have shown that the number of collisions can be reduced to zero in a simple way, there have been a couple of remaining issues to solve, such as dynamic parameter adjustment and fairness to legacy DCF nodes in terms of channel access opportunity. Recently, In-Band Full Duplex (IBFD) communication has received much attention, because it has significant potential to improve the communication capacity of a radio band. IBFD means that a node can simultaneously transmit one signal and receive another signal in the same band at the same time. In order to maximize the performance of IBFD communication capability and to fairly share access to the wireless medium among distributed devices in WLANs, a number of IBFD MAC protocols have been proposed. However, little attention has been paid to fairness issues between half duplex nodes (i.e. nodes that can either transmit or receive but not both simultaneously in one time-frequency resource block) and IBFD capable nodes in the presence of the hidden node problem.

<p>U disertaciji je predstavljen postupak GSSKN (generalizovani postupak sumiranja<br />struja i korekcija napona) integrisan u DMS. Integracija postupka GSSKN u DMS se<br />sastoji od sledećeg: 1) postupak GSSKN se naslanja na jedinstvenu bazu podataka DMS i<br />2) rezultati dobijeni proračunom tokova snaga korišćenjem postupka GSSKN koriste<br />se u velikom broju ostalih funkcija DMS. Standardni postupak BFS (čišćenje<br />unaprjed/unazad), koji je razvijen za proračun tokva snaga uravnoteženih<br />distributivnih mreža u simetričnim režimima, u ovoj disertaciji je generalizovan na<br />uravnotežene mreže u nesimetričnim režimima, neuravnotežene distributivne mreže<br />(u nesimetričnim režimima), sa obuhvaćenim miksovanim mrežama, a da su pri tome u<br />potpunosti zapaženi robustnost, efikasnost i brzina u odnosu na ostale postupke.<br />Odnosno, u ovoj disertaciji je predložen GSSKN za proračun bilo kako složenih<br />slaboupetljanih distributivnih mreža s distributivnim generatorima, koji ima sve<br />osobine i prednosti u odnosu na ostale postupke, kao što su ih imali standardni<br />postupci BFS za proračun tokova snaga uravnoteženih slaboupetljanih<br />distributivnih mreža sa distributivnim generatorima u simetričnim režimima.<br />Dakle, osnovni cilj ove disertacije glasi: pokazati da standardne postupke BFS ne<br />samo da ne treba napuštati prilikom proračuna tokova snaga neuravnoteženih<br />slaboupetljanih aktivnih mreža (uključene miksovane), već da je to napuštanje<br />kontraproduktivno, bar sa aspekta postupaka koji su do sada objavljeni u literaturi.</p> / <p>The dissertation presents GBFS (General Backward/Forward Sweeping) procedure<br />which is integrated in DMS. The integration of the GBFS procedure in DMS<br />consists of the following: 1) the GBFS procedure is based on the unique DMS<br />database and 2) the results obtained from load flow calculation by application of<br />GBFS procedure are used in many other DMS applications. The standard BFS<br />procedure (Backward/Forward Sweeping), developed for the load flow calculation<br />of balanced distribution networks in symmetrical states, in this dissertation is<br />generalized to balanced networks in asymmetrical states, unbalanced distribution<br />networks (in asymmetrical states), including mixed networks. In addition, the<br />robustness, efficiency and speed comparing to other procedures, have been saved.<br />In other words, this dissertation proposes the GBFS procedure for calculation of<br />any composite weakly meshed distribution networks with distribution generators. It<br />has all the properties and advantages as compared to other procedures, like<br />standard BFS procedures applied for load flow calculation of balanced weakly<br />meshed distribution networks with distribution generators in symmetrical states.<br />Therefore, the basic objective of this dissertation is as follows: to show that the<br />standard BFS procedures should not be abandoned when performing the load flow<br />calculation of unbalanced weakly meshed active networks (mixed included), and<br />that, on the contrary, abandoning them would be counterproductive, at least from<br />the aspect of procedures published so far.</p>