On multimodality of obnoxious faclity location models

Obnoxious single facility location models are models that have the aim to find the best location for an undesired facility. Undesired is usually expressed in relation to the so-called demand points that represent locations hindered by the facility. Because obnoxious facility location models as a rule are multimodal, the standard techniques of convex analysis used for locating desirable facilities in the plane may be trapped in local optima instead of the desired global optimum. It is assumed that having more optima coincides with being harder to solve. In this thesis the multimodality of obnoxious single facility location models is investigated in order to know which models are challenging problems in facility location problems and which are suitable for site selection. Selected for this are the obnoxious facility models that appear to be most important in literature. These are the maximin model, that maximizes the minimum distance from demand point to the obnoxious facility, the maxisum model, that maximizes the sum of distance from the demand points to the facility and the minisum model, that minimizes the sum of damage of the facility to the demand points. All models are measured with the Euclidean distances and some models also with the rectilinear distance metric. Furthermore a suitable algorithm is selected for testing multimodality. Of the tested algorithms in this thesis, Multistart is most appropriate. A small numerical experiment shows that Maximin models have on average the most optima, of which the model locating an obnoxious linesegment has the most. Maximin models have few optima and are thus not very hard to solve. From the Minisum models, the models that have the most optima are models that take wind into account. In general can be said that the generic models have less optima than the weighted versions. Models that are measured with the rectilinear norm do have more solutions than the same models measured with the Euclidean norm. This can be explained for the maximin models in the numerical example because the shape of the norm coincides with a bound of the feasible area, so not all solutions are different optima. The difference found in number of optima of the Maxisum and Minisum can not be explained by this phenomenon

Localização de serviços semiobnóxios: uma proposta de sistema de apoio à decisão

A localização de serviços semiobnóxios é caracterizada por critérios contraditórios, que podem ser expressos como forças de atracção e repulsão. Os serviços semiobnóxios definem-se como sendo desejáveis para as comunidades pelos benefícios que geram, mas que por outro lado são indesejáveis pelos efeitos negativos (obnóxios) que lhes estão associados. Exemplos de serviços semiobnóxios são: aeroportos, estações de tratamento de resíduos sólidos, estações de tratamento de águas e certos tipos de indústrias. Os agentes de decisão são assim confrontados com a necessidade de localizar esses serviços de modo a servir melhor as comunidades, simultaneamente reduzindo os impactos negativos. Outros factores tidos em conta, na localização de serviços semiobnóxios, são os custos relacionados com a distância dos serviços às comunidades que se pretendem mínimos. Pretende-se então, maximizar a acessibilidade aos serviços conjuntamente com a minimização dos efeitos obnóxios. Os modelos desenvolvidos para a resolução deste tipo de problemas são frequentemente apresentados numa linguagem mais orientada para especialistas em Investigação Operacional (IO) e menos adequada para os decisores nas diferentes organizações, quer sejam governamentais, autárquicas ou empresariais. O objectivo deste trabalho é o desenvolvimento de um Sistema de Apoio à Decisão para Problemas de Localização de Serviços Semiobnóxios. Com transferência de algum conhecimento científico da IO para os agentes de decisão, facilitando a escolha das localizações dos serviços ao apresentar alternativas de qualidade, tendo presente a simplicidade e a facilidade de utilizaçãoThe location of semi-obnoxious services is characterized by opposing criteria, which can be expressed as attraction and repulsion forces. The semi- obnoxious services can be defined as being desirable to the communities for the benefits they generate, but on the other side, are undesirable for their associated obnoxious effects. Examples of semi-obnoxious services are: airports, solid waste treatment facilities, water or effluent treatment facilities and certain types of industries. Therefore, the decision agents are faced with the need to locate those services in a way that they serve best the communities, while simultaneously reducing the negative effects. Other factors to hold in account in the location of semi-obnoxious services, are the costs concerning the distances between the services and the communities. Those costs are to minimize, which is equivalent to maximize the accessibility. Consequently, the problem becomes to maximize the accessibility while minimizing the obnoxious effects. It is frequent that the developed models to solve this type of problems are presented in an “Operations Research” (OR) experts oriented language. This may not be suitable for the decision agents at governmental or private organizations. The main goal of this work is to develop a Decision Support System for the Problem of Locating Semi-obnoxious Services. This way some of the OR scientific knowledge is transferred to the decision agents, allowing a usable system that provides quality location alternatives, making easier to select the best locations for the servicesMestrado em Gestã

Problemas de localização-distribuição de serviços semiobnóxios: aproximações e apoio à decisão

Doutoramento em Gestão IndustrialA presente tese resulta de um trabalho de investigação cujo objectivo se centrou no problema de localização-distribuição (PLD) que pretende abordar, de forma integrada, duas actividades logísticas intimamente relacionadas: a localização de equipamentos e a distribuição de produtos. O PLD, nomeadamente a sua modelação matemática, tem sido estudado na literatura, dando origem a diversas aproximações que resultam de diferentes cenários reais. Importa portanto agrupar as diferentes variantes por forma a facilitar e potenciar a sua investigação. Após fazer uma revisão e propor uma taxonomia dos modelos de localização-distribuição, este trabalho foca-se na resolução de alguns modelos considerados como mais representativos. É feita assim a análise de dois dos PLDs mais básicos (os problema capacitados com procura nos nós e nos arcos), sendo apresentadas, para ambos, propostas de resolução. Posteriormente, é abordada a localização-distribuição de serviços semiobnóxios. Este tipo de serviços, ainda que seja necessário e indispensável para o público em geral, dada a sua natureza, exerce um efeito desagradável sobre as comunidades contíguas. Assim, aos critérios tipicamente utilizados na tomada de decisão sobre a localização destes serviços (habitualmente a minimização de custo) é necessário adicionar preocupações que reflectem a manutenção da qualidade de vida das regiões que sofrem o impacto do resultado da referida decisão. A abordagem da localização-distribuição de serviços semiobnóxios requer portanto uma análise multi-objectivo. Esta análise pode ser feita com recurso a dois métodos distintos: não interactivos e interactivos. Ambos são abordados nesta tese, com novas propostas, sendo o método interactivo proposto aplicável a outros problemas de programação inteira mista multi-objectivo. Por último, é desenvolvida uma ferramenta de apoio à decisão para os problemas abordados nesta tese, sendo apresentada a metodologia adoptada e as suas principais funcionalidades. A ferramenta desenvolvida tem grandes preocupações com a interface de utilizador, visto ser direccionada para decisores que tipicamente não têm conhecimentos sobre os modelos matemáticos subjacentes a este tipo de problemas.This thesis main objective is to address the location-routing problem (LRP) which intends to tackle, using an integrated approach, two highly related logistics activities: the location of facilities and the distribution of materials. The LRP, namely its mathematical formulation, has been studied in the literature, and several approaches have emerged, corresponding to different real-world scenarios. Therefore, it is important to identify and group the different LRP variants, in order to segment current research and foster future studies. After presenting a review and a taxonomy of location-routing models, the following research focuses on solving some of its variants. Thus, a study of two of the most basic LRPs (capacitated problems with demand either on the nodes or on the arcs) is performed, and new approaches are presented. Afterwards, the location-routing of semi-obnoxious facilities is addressed. These are facilities that, although providing useful and indispensible services, given their nature, bring about an undesirable effect to adjacent communities. Consequently, to the usual objectives when considering their location (cost minimization), new ones must be added that are able to reflect concerns regarding the quality of life of the communities impacted by the outcome of these decisions. The location-routing of semi-obnoxious facilities therefore requires to be analysed using multi-objective approaches, which can be of two types: noninteractive or interactive. Both are discussed and new methods proposed in this thesis; the proposed interactive method is suitable to other multi-objective mixed integer programming problems. Finally, a newly developed decision-support tool to address the LRP is presented (being the adopted methodology discussed, and its main functionalities shown). This tool has great concerns regarding the user interface, as it is directed at decision makers who typically don’t have specific knowledge of the underlying models of this type of problems

OPTIMIZATION OF RAILWAY TRANSPORTATION HAZMATS AND REGULAR COMMODITIES

Transportation of dangerous goods has been receiving more attention in the realm of academic and scientific research during the last few decades as countries have been increasingly becoming industrialized throughout the world, thereby making Hazmats an integral part of our life style. However, the number of scholarly articles in this field is not as many as those of other areas in SCM. Considering the low-probability-and-high-consequence (LPHC) essence of transportation of Hazmats, on the one hand, and immense volume of shipments accounting for more than hundred tons in North America and Europe, on the other, we can safely state that the number of scholarly articles and dissertations have not been proportional to the significance of the subject of interest. On this ground, we conducted our research to contribute towards further developing the domain of Hazmats transportation, and sustainable supply chain management (SSCM), in general terms. Transportation of Hazmats, from logistical standpoint, may include all modes of transport via air, marine, road and rail, as well as intermodal transportation systems. Although road shipment is predominant in most of the literature, railway transportation of Hazmats has proven to be a potentially significant means of transporting dangerous goods with respect to both economies of scale and risk of transportation; these factors, have not just given rise to more thoroughly investigation of intermodal transportation of Hazmats using road and rail networks, but has encouraged the competition between rail and road companies which may indeed have some inherent advantages compared to the other medium due to their infrastructural and technological backgrounds. Truck shipment has ostensibly proven to be providing more flexibility; trains, per contra, provide more reliability in terms of transport risk for conveying Hazmats in bulks. In this thesis, in consonance with the aforementioned motivation, we provide an introduction into the hazardous commodities shipment through rail network in the first chapter of the thesis. Providing relevant statistics on the volume of Hazmat goods, number of accidents, rate of incidents, and rate of fatalities and injuries due to the incidents involving Hazmats, will shed light onto the significance of the topic under study. As well, we review the most pertinent articles while putting more emphasis on the state-of-the-art papers, in chapter two. Following the discussion in chapter 3 and looking at the problem from carrier company’s perspective, a mixed integer quadratically constraint problem (MIQCP) is developed which seeks for the minimization of transportation cost under a set of constraints including those associating with Hazmats. Due to the complexity of the problem, the risk function has been piecewise linearized using a set of auxiliary variables, thereby resulting in an MIP problem. Further, considering the interests of both carrier companies and regulatory agencies, which are minimization of cost and risk, respectively, a multiobjective MINLP model is developed, which has been reduced to an MILP through piecewise linearization of the risk term in the objective function. For both single-objective and multiobjective formulations, model variants with bifurcated and nonbifurcated flows have been presented. Then, in chapter 4, we carry out experiments considering two main cases where the first case presents smaller instances of the problem and the second case focuses on a larger instance of the problem. Eventually, in chapter five, we conclude the dissertation with a summary of the overall discussion as well as presenting some comments on avenues of future work

Comparison of the vocabularies of the Gregg shorthand dictionary and Horn-Peterson's basic vocabulary of business letters

This study is a comparative analysis of the vocabularies of Horn and Peterson's The Basic Vocabulary of Business Letters1 and the Gregg Shorthand Dictionary.2 Both books purport to present a list of words most frequently encountered by stenographers and students of shorthand. The, Basic Vocabulary of Business Letters, published "in answer to repeated requests for data on the words appearing most frequently in business letters,"3 is a frequency list specific to business writing. Although the book carries the copyright date of 1943, the vocabulary was compiled much earlier. The listings constitute a part of the data used in the preparation of the 10,000 words making up the ranked frequency list compiled by Ernest Horn and staff and published in 1926 under the title of A Basic Writing Vocabulary: 10,000 Words Lost Commonly Used in Writing. The introduction to that publication gives credit to Miss Cora Crowder for the contribution of her Master's study at the University of Minnesota concerning words found in business writing. With additional data from supplementary sources, the complete listing represents twenty-six classes of business, as follows 1. Miscellaneous 2. Florists 3. Automobile manufacturers and sales companie

Integrated conservation in Mexico: reconciling conservation and sustainable development within natural protected areas

This research focuses on the extent in which integrated conservation as an approach of management for protected areas can reconcile with the effective conservation of biodiversity while supporting the sustainable development of local communities that exist within or surrounding the boundaries of the reserve. It contributes to the global debate on the appropriateness of local community participation in conservation and the potential challenges facing the integration of conservation into local development. In order to do that, two case studies were carried out in biosphere reserves in Mexico where the aim of implementing this approach was identified. An Integrated Conservation Assessment (ICA) was designed to assess the implementation of integrated conservation from the local stakeholders’ perception. The components of the ICA include; transfer of local benefits and costs, sustainable livelihoods and local participation. One year’s field work was carried out to collect information from the local communities through participant observation, informal interviews and user groups meetings. External stakeholders were also interviewed to obtain a balanced impression of integrated conservation that in turn complemented and expanded upon the perceptions of the local community. A comparative analysis demonstrates that one of the reserves has attained a significantly higher level of integrated conservation in comparison to the other. In order to explain different outcomes of results between the two case studies, the research discusses some of the conditions that favour the implementation of an integrated conservation approach, both from the managers and from the local community’s perspectives. These results support discussions on finding win win situations to increase the effectiveness of conservation and build local capacity for sustainable development

"Keeping the Kids out of Trouble": Extra-Domestic Labour and Social Reproduction in Toronto's Regent Park, 1959-2012

This dissertation is an historical ethnography of social reproduction in Regent Park, Canadas first public housing project. Built from 1948 to 1959 as part of a modernist slum clearance initiative, Regent Park was deemed a failure soon after it opened and was then stigmatised for decades thereafter, both for being a working-class enclave and for epitomising an outdated approach to city planning. A second redevelopment began in 2005, whereby the project is being demolished and rebuilt as a mix of subsidised and market housing, retail space, and other amenities. Despite its enduring stigmatisation, however, many current and former residents retain positive memories of Regent Park. Participants in this study tended to refer to it as a community, indicating senses of shared ownership and belonging that residents themselves built in everyday life. This dissertation emphasises the capacity of working-class people to build and maintain community on their own terms, and in spite of multiple and intersecting constraints. To theorise community-building, I begin from the concept of social reproduction: the work of maintaining and replenishing stable living conditions, both day-to-day and across generations. Much of this work is domestic labour unpaid tasks done inside the household such as cooking, cleaning, and raising children. In Regent Park, social reproduction demanded even more of residents: the stability of households was often threatened by dangers and challenges unique to life in a stigmatised housing project, and it was largely left up to residents themselves to redress these. To account for the considerable effort this involved, I propose a concept adjacent to domestic labour that I call extra-domestic labour: unpaid work done outside the household, usually through informal collaboration among members of different households, that is necessary for social reproduction. Extra-domestic labour built community and fostered a territorial solidarity that, I argue, is the primary means through which Regent Parkers developed class consciousness. This was often expressed through emic class categories, which were defined in relation to the locality more so than the workplace, and through which people interpreted their position in the wider social order

Sport, space and segregation Pietermaritzburg, 1900-1980

Sport is located historically within its political, economic, cultural and social context in order to assess its role in human and spatial relations; and its meaning for various communities. This study aims to measure the impact of dominant ideology (imperialism, segregation and apartheid), the degree to which sport was used instrumentally by the authorities, and the extent to which it was seen as a site of struggle by the oppressed. The main sources for this thesis were archival and published material emanating from the municipality. Before apartheid matured and became more secretive, they were remarkably candid about official aims and objectives. A wide variety of secondary sources was consulted; and interviews conducted. The conclusion is that sport is an appropriate lens through which to view urban history and the relationships that shape it. Driven by a consistent ideological desire for White separateness, sport reflected social hegemony and assumptions about relative competence and ability. Instrumental use of sport by the local authority, apart from a skewed use of economic resources to unite whites and maintain their distance from other communities, was poorly regarded. This was because of the availability of other, coercive means of control and the dispensability of the individuals targeted. Black sportspersons were in effect squatters at impermanent facilities. Black recreation was a challenge to White ideas about the use of urban space. For Africans, the controlled area preferred by the authorities was the beerhall, not the sports field. Effective resistance organised around sport emerged only when the authorities needed Asian and Coloured cooperation to implement group areas and at this point sport became a notable site of struggle. Ultimately sports facilities, originally a symbol of White civilisation and authority, became a potent emblem of the spatial conflict that characterised apartheid. They also reflected the fact that South African urban geography had always been an evolving saga of insiders and outsiders. Sport provided the proponents of White dominance with a theatre for propaganda; while at the same time offering its protagonists a stage upon which to demonstrate their opposition. In this scenario hegemony was in a state of periodic flux. For a more descriptive abstract of this thesis, see the section 'Final overview' on pages 353-356