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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.
531

Planning Resource Requirements in Rail Freight Facilities by Applying Machine Learning

Ruf, Moritz 10 January 2022 (has links)
Diese Dissertation verknüpft eisenbahnbetriebswissenschaftliche Grundlagen mit Methoden aus den Disziplinen Unternehmensforschung (Operations Research) und Maschinelles Lernen. Gegenstand ist die auf den mittelfristigen Zeithorizont bezogene Ressourcenplanung von Knoten des Schienengüterverkehrs, die sogenannte taktische Planung. Diese spielt eine wesentliche Rolle für eine wirtschaftliche und qualitativ hochwertige Betriebsdurchführung. Knoten des Schienengüterverkehrs stellen neuralgische Punkte in der Transportkette von Waren auf der Schiene dar. Sie dienen der Durchführung einer Vielzahl unterschiedlicher betrieblicher Prozesse zur Sicherstellung eines definierten Outputs an Zügen in Abhängigkeit eines jeweils gegebenen Inputs. Die Bereitstellung eines zu den Betriebsanforderungen passenden Ressourcengerüsts ist Teil der taktischen Planung und hat wesentlichen Einfluss auf die Qualität der Prozesse in den Knoten, im Speziellen, sowie auf die vor- und nachgelagerte Transportdurchführung im Allgemeinen. Die Bemessung des notwendigen Personals, der Betriebsmittel und der Infrastruktur für einen Betriebstag, die sogenannte Ressourcendimensionierung, ist in der Praxis geprägt durch einen erheblichen manuellen Aufwand sowie eine große Abhängigkeit von der Datenqualität. Vor diesem Hintergrund und zur Überwindung dieser Nachteile schlägt diese Dissertation ein neues Verfahren zur Ressourcendimensionierung vor. Exemplarisch wird der Fokus auf die großen Knoten des Einzelwagenverkehrs gelegt, die sogenannten Rangierbahnhöfe. In diesen werden Eingangszüge zerlegt, Güterwagen entsprechend ihrer Ausgangsrichtung sortiert und gesammelt, sowie neue Ausgangszüge gebildet und bereitgestellt. Nach dem Stand der Technik werden für die Ressourcendimensionierung mehrere Monate bis wenige Wochen vor der Betriebsdurchführung Rangierarbeitspläne erstellt. Diese umfassen einen detaillierten Arbeitsfolgenplan inklusive Terminierung von Prozessen sowie deren Ressourcenbelegung. Die Rangierarbeitspläne bilden die Grundlage für die Ressourcenanforderung. Aufgrund sich ändernder Nebenbedingungen vor dem Betriebstag und dem stochastischen Charakter der Betriebsprozesse sowohl im Netz als auch in den Knoten können die in der taktischen Planung erstellten Rangierarbeitspläne nur begrenzt für die Durchführung verwendet werden. Als Beispiele sollen das Einlegen von Sonderzügen, Unregelmäßigkeiten bei den Transporten und Witterungsauswirkungen angeführt werden. Der betriebene Planungsaufwand begründet sich in den komplexen Zusammenhängen zwischen den Betriebsprozessen und der größtenteils fehlenden EDV-Unterstützung, was eine Ermittlung der Ressourcendimensionierung bisher erschwert. Die Folge ist eine Diskrepanz zwischen der Datenqualität als Eingangsgröße für die Planung und der Präzision des Rangierarbeitsplans als Ausgangsgröße, was als Konsequenz eine Scheingenauigkeit der Planung und unter Umständen eine Über- oder Unterdimensionierung der Ressourcen mit sich bringt. Das zeigt, dass die Planung verkürzt werden muss und neue Hilfsmittel erforderlich sind. Motiviert durch diese Diskrepanz und den neuen Möglichkeiten, die die Methoden aus den Bereichen des Operations Research und des Maschinellen Lernens bieten, stellt diese Dissertation ein neues Planungsverfahren Parabola bereit. Parabola ermittelt mit geringerem Planungsaufwand und hoher Qualität relevante Kenngrößen für die Ressourcendimensionierung in Knoten des Schienengüterverkehrs. Dies beschleunigt den taktischen Planungsprozess, reduziert Scheingenauigkeiten bei der Ressourcendimensionierung vor der Betriebsdurchführung und orientiert sich daran, wann welche Entscheidungen zuverlässig und genau zu treffen sind. Folglich wird die Detailtiefe der Planung mit der Zuverlässigkeit der Daten in Einklang gebracht. Das in der Dissertation bereitgestellte Planungsverfahren Parabola analysiert eine ausreichend große Anzahl errechneter Rangierarbeitspläne und / oder historischer Betriebsdaten. Das dabei trainierte Regressionsmodell wird anschließend zur Bestimmung des Ressourcengerüsts genutzt. Die Kalibrierung der Regressionsmodelle erfordert hinreichend viele Rangierarbeitspläne. Für deren Erzeugung wird exemplarisch am Beispiel von Rangierbahnhöfen in dieser Dissertation ein ganzheitliches mathematisches lineares Programm entwickelt, das erstmalig sämtliche für die taktische Planung eines Rangierbahnhofs relevanten Entscheidungsprobleme vom Zugeingang bis zum Zugausgang abbildet. Dieses beinhaltet die Definition der Verknüpfung zwischen Eingangs- und Ausgangszügen, sogenannter Wagenübergänge, sowie die Terminierung sämtlicher Betriebsprozesse mit ihrer Zuweisung zu örtlichen Mitarbeitern, Betriebsmitteln und Infrastruktur. Die bestehenden mathematischen Modelle in der bisherigen Literatur beschränken sich lediglich auf Teile dieses Problems. Es folgt die systematische Erzeugung von Problemstellungen, sogenannten Instanzen, zur Generierung eines repräsentativen Testpools. Die Instanzen dieses NP-schweren Problems sind für generische, exakte Lösungsverfahren in akzeptabler Zeit nicht zuverlässig lösbar. Daher wird eine maßgeschneiderte Metaheuristik, konkret ein Verfahren der Klasse Adaptive Large Neighborhood Search (ALNS), entwickelt. Diese bewegt sich durch den Lösungsraum, indem schrittweise mittels mehrerer miteinander konkurrierender Subheuristiken eine vorher gefundene Lösung erst zerstört und anschließend wieder repariert wird. Durch unterschiedliche Charakteristika der Subheuristiken und einer statistischen Auswertung ihres jeweiligen Beitrags zum Lösungsfortschritt, gelingt es der ALNS, sich an das Stadium der Lösungssuche und an die jeweilige Problemstruktur anzupassen. Die in dieser Dissertation entwickelte ALNS erzeugt für realistische Instanzen eines Betriebstages Lösungen in hoher Qualität binnen weniger Minuten Rechenzeit. Basierend auf den erzeugten Rangierarbeitsplänen wurden für die Entwicklung des Planungsverfahrens insgesamt fünf Regressionstechniken getestet, die die Ausgangsgrößen der Pläne – Bedarf an Lokomotiven, Personal und Infrastruktur – prognostizieren. Die vielversprechendsten Ergebnisse werden durch die Methoden Tree Boosting sowie Random Forest erzielt, die in über 90 % der Fälle den Ressourcenbedarf für Personale und Lokomotiven exakt und für Infrastruktur mit einer Toleranz von einem Gleis je Gleisgruppe prognostizieren. Damit ist dieses Regressionsmodell nach ausreichender Kalibrierung entsprechend örtlicher Randbedingungen geeignet, komplexere Planungsverfahren zu ersetzen. Die Regressionsmodelle ermöglichen die Abstrahierung von Mengengerüsten und Leistungsverhalten von Knoten des Schienengüterverkehrs. Daher ist beispielsweise ein konkreter Fahrplan von und zu den Knoten nicht mehr notwendige Voraussetzung für die taktische Planung in Rangierbahnhöfen. Da das Regressionsverfahren aus vielen Rangierarbeitsplänen lernt, verringert sich die Abhängigkeit von einzelnen Instanzen. Durch die Kenntnis von vielen anderen Plänen können robustere Ressourcengerüste prognostiziert werden. Neben dem in dieser Dissertation ausgearbeiteten Anwendungsfall in der taktischen Planung in Knoten des Schienengüterverkehrs, eröffnet das vorgeschlagene neue Planungsverfahren Parabola eine Vielzahl an weiteren Einsatzfeldern. Die Interpretation des trainierten Regressionsmodells erlaubt das tiefgründige Verständnis des Verhaltens von Knoten des Schienengüterverkehrs. Dies ermöglicht ein besseres Verstehen der Engpässe in diesen Knoten sowie die Identifikation relevanter Treiber der Ressourcendimensionierung. Weiter können diese Modelle bei der Erstellung von netzweiten Leistungsanforderungen Berücksichtigung finden. Mit der in dieser Dissertation erfolgten Bereitstellung von Parabola wird durch Nutzung neuartiger Methoden aus dem Operations Research und Maschinellen Lernen das Instrumentarium der eisenbahnbetriebswissenschaftlichen Verfahren und Modelle sinnvoll erweitert. / This dissertation combines the knowledge of railway operations management with methods from operations research and machine learning. It focuses on rail freight facilities, especially their resource planning at a tactical level. The resource planning plays a crucial role for economical operations at high quality. The rail freight facilities represent neuralgic points in the transport chain of goods by rail. Their task is to carry out a multitude of different operational processes to ensure a defined output of trains, depending on a given input. Providing resource requirements appropriate to the amount of work has a significant impact on the quality of the processes in the facilities in particular and on the up- and downstream transport performance in general. The correct dimensioning of resource requirements, which include the necessary staff, locomotives, and infrastructure for an operating day, is characterized by a considerable manual effort and a large dependency on the data accuracy. Against this background and to overcome these drawbacks, this dissertation proposes a new method for resource requirements. The focus is on the large facilities of single wagonload traffic, the so-called classification yards, in which inbound trains are disassembled, railcars are classified according to their outbound direction, and new outbound trains are formed. Nowadays, shunting work plans are created several months to a few weeks before operations. These operating plans comprise a detailed work sequence plan, including process scheduling, and resource allocation. The operating plans form the basis for resource requirements. Due to the changing constraints prior to operations, e.g., the addition of special trains, and the stochastic nature of the operational processes, for instance caused by weather conditions, shunting work plans can only be used for execution to a limited extent. This effort is made for planning due to the complex interdependencies between the operational processes and the predominant lack of IT support, which makes it difficult to determine resource requirements. The result is a discrepancy between the accuracy of the data as an input variable and the precision of the shunting work plan as an output variable. This leads to an illusory precision of the planning and possibly to an oversizing or undersizing of the resources. Hence, planning must be shortened and new tools are required. Motivated by this discrepancy and the new possibilities offered by methods from the _elds of operations research and machine learning, this dissertation provides a new planning method Parabola. Parabola determines with less planning effort and at high quality relevant parameters for resource requirements in rail freight facilities. This accelerates the planning process, reduces illusory precision before operations are carried out and enables decision-making with sufficient reliability due to the data accuracy. Consequently, the level of detail of the planning is harmonized with the reliability of the data. The planning procedure Parabola involves the analysis of numerous calculated operating plans and / or historical operating data. This trains a regression model that can then be used to determine the resource requirements. The calibration of the regression models requires many operating plans. For their generation, an integrated mathematical linear program is developed in this dissertation using the example of classification yards; for the first time, one program covers all relevant decision problems of tactical planning in a classification yard, from the train arrival to the train departure. This includes the definition of the connection between inbound and outbound trains, so-called railcar interchanges, as well as the scheduling of all operational processes with their assignment to local staff, locomotives, and infrastructure. All existing mathematical models in the literature are limited to parts of the problem. Thereafter follows a systematic generation of a test pool of problems named instances. The instances of this NP-hard problem cannot be reliably solved within an acceptable time frame with general-purpose solvers. Therefore, a tailored metaheuristic, namely an adaptive large neighborhood search (ALNS), is developed. It moves through the solution space by first destroying and then repairing a solution stepwise. Several competing subheuristics are available for this purpose. The ALNS combines multiple subheuristics, which have different characteristics and contribute to the solution progress, as determined by statistical evaluation. Consequently, the ALNS successfully adapts to the progress of the solution and to the problem structure. The ALNS, which is developed in this dissertation, generates high-quality solutions for realistic instances of an operating day in a few minutes of computing time. Based on the generated operating plans, five regression methods predicting the output variables of the operating plans – demand for locomotives, staff, and infrastructure – are tested. The most promising results are achieved by the methods tree boosting and random forest, which predict the resource requirements in over 90% of the cases for staff and locomotives accurately and for infrastructure with a tolerance of one track per bowl. Thus, a regression model can replace the more complex planning procedures after sufficient calibration according to local restrictions. The regression models allow the abstraction of quantity structures and performance behavior. Hence, for example, a dedicated timetable is no longer a prerequisite for tactical planning in classification yards. Since regression methods learn from many operating plans, the dependence on individual instances is reduced. By knowing many other plans, the regression model can predict robust resource requirements. In addition to the use case in tactical planning in rail freight facilities, the proposed new planning method Parabola opens a multitude of further _elds of application. By interpreting the trained regression model, the behavior of rail freight facilities can be understood in depth. Under certain circumstances, this allows a better understanding of the bottlenecks in these facilities and the relevant drivers of resource dimensioning. Furthermore, these models have potential applications in the design of network-wide performance requirements. By providing Parabola in this dissertation, the toolbox of railroad management science procedures and models is sensibly extended by using novel methods from operations research and machine learning.
532

Pediatric Cochlear Implant Outcomes in Auditory Neuropathy/Auditory Dys-Synchrony

Eby, Christine A. 07 July 2004 (has links)
No description available.
533

Perceptions of the Police and Fear of Crime: The Role of Neighborhood Social Capital

Williams, Seth Alan 18 November 2015 (has links)
No description available.
534

Neighborhood Satisfaction, Physical and Perceived Characteristics

Hur, Misun 24 December 2008 (has links)
No description available.
535

Measuring locational equity and accessibility of neighborhood parks in Kansas City, Missouri

Besler, Erica L. January 1900 (has links)
Master of Regional and Community Planning / Department of Landscape Architecture/Regional and Community Planning / Jason Brody / Recent research has focused on assessing equity with regards to location of public services and the population served. Instead of equality, equity involves providing services in proportion to need, rather than equal access for everyone. This study uses three commonly identified measures of accessibility (minimum distance, travel cost, and gravity potential) to assess how equitable higher-need residential populations of Kansas City, MO are served by neighborhood parks. Using Census 2000, socio-economic block group data, areas with high population concentrations of African-American and Hispanic populations, as well as areas of high density and low income are characterized as having the most need. However, correlations of higher-need populations with the accessibility measures reveal patterns of equity within the Kansas City. MO study area. Results indicated that while most of the high need population was adequately and equitably served by neighborhood parks, there were still block groups that did not have access to this type of public resource. This research follows methods proposed in previous studies that utilize the spatial mapping and analysis capabilities of ArcGIS and promote the use of these tools for city planners and future park development and decisions.
536

Responding to shock: a collaborative process for the St. Roch neighborhood

Mahoney, J. Liam January 1900 (has links)
Master of Landscape Architecture / Department of Landscape Architecture/Regional and Community Planning / Lee R. Skabelund / Hurricane Katrina displaced many New Orleans residents, leaving in its wake tens of thousands of vacant lots and buildings. In 2010, estimates show that over 57,000 properties lay empty in the city, especially in the poorer neighborhoods. These properties are not contributing to the fabric of the city; in most places, they are a sign of defeat, an eyesore, or a haven for crime. The neighborhood of St. Roch is experiencing the negative effects of these properties day in and day out and from year to year. Almost a quarter of the lots are vacant in the St. Roch neighborhood, leading to crime and creating a nuisance and a blemish on the community. Coupled with the lack of ownership there is an ailing stormwater management infrastructure leading to areas of flooding after routine storms. In addition to these concerns, there is a lack of fresh, inexpensive and accessible food throughout the area. Although St. Roch’s vacant lots have a negative effect on the community, they present a tremendous opportunity. Their dispersal around the neighborhood presents the opportunity to connect them to churches, schools, retail outlets, as well as providing other uses and services to the neighborhood. The thoughtful design of these locations will demonstrate a site-sensitive approach to the local ecology, culture, and economy of the neighborhood. Such design includes the community throughout the entire lifecycle of each site from its planning phase to the end of its use. The primary goal throughout the planning and design process is to foster stewardship for both the landscape and the community as a whole by means of collaborative planning, direct interaction with each site during implementation, and the observation and monitoring of crucial processes throughout a site’s lifecycle. The intent of this project is to apply a participatory framework to the site design process in order to rejuvenate critical areas of the St. Roch neighborhood. This project seeks to demonstrate the need for a collaborative process while allowing for a balance between the experts who help design each site and the community members who take ownership of the renewed parcels.
537

The local food environment and its association with obesity among low-income women across the urban-rural continuum

Ford, Paula Brigid January 1900 (has links)
Doctor of Philosophy / Department of Human Nutrition / David A. Dzewaltowski / The prevalence of obesity within the U.S. has risen dramatically in the past thirty years. Recent changes in food and physical activity environments may contribute to increased obesity prevalence, suggesting that disparities in these environments may be linked to the increased risk of obesity observed in low-income, and racial/ethnic minority women. This dissertation characterizes the local food environment experienced by low-income women who participate in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) in Kansas, evaluates whether characteristics of the local food environment contribute to obesity risk, and examines how these relationships vary across the urban-rural continuum. Chapter One reviews the relevant literature examining the association between obesity and local food environments, and identifies three testable hypotheses that serve as the framework for later chapters. Chapter Two characterizes the local food environment and examines geographic, racial, ethnic, and socioeconomic disparities in the availability of small grocery stores and supermarkets. Chapter Three examines the association between store availability and obesity risk at an individual level among participants in the WIC Program, while Chapter Four utilizes multi-level modeling to examine the relationships between tract deprivation, tract store availability and body mass index (BMI). Significant geographic disparities were observed in the availability of small grocery and supermarkets. Racial and ethnic disparities observed within tracts were not observed when examining store availability in a 1-mile radius around the residence of WIC mothers. The majority of women participating in the WIC program resided within a 1-mile radius of a small grocery store, and micropolitan and metropolitan WIC mothers had a multiplicity of food stores available within a 3-mile radius of residence. Food store availability was associated with increased obesity risk only in micropolitan areas. The availability of food stores did not mediate the association between tract deprivation and BMI, which varied across the urban-rural continuum. Overall, these results suggest that the relationship between local food environments and eating behaviors is complex, that limited store availability does not contribute to increased obesity risk in vulnerable populations, and that the association between local food environments and obesity risk varies across the urban-rural continuum.
538

Home, neighborhood, and renewal: resident perceptions of forced relocation

Wilcox, F. Rowan January 1900 (has links)
Master of Arts / Department of Geography / Max Lu / Given the ongoing incidence of housing displacement related to the commercial redevelopment of neighborhoods, and its implications for the health and quality of life of affected households and communities, there is a need for insight into what factors influence the quality of a move and movers' chances of successful post-move adjustment. In this study, qualitative analysis of in-depth interviews with 26 men and women representing 18 households from three redeveloped eastern Kansas neighborhoods was employed to examine residents' experiences of displacement. Five factors were examined: attachment to home and neighborhood, community social ties, relative sense of control and mastery over the circumstances of relocation, opinions of the amount of monetary compensation or relocation assistance received, and support for a redevelopment project. The results show that attachment to home influenced feelings about having to move, although it did not preclude contentment with a post-move dwelling. Attachment to neighborhood had both social and environmental components. Neighborhood social ties were difficult to replicate for many residents in their post-move neighborhoods. Perceptions of control over the circumstances of a move were negatively affected by problems with communication and information-sharing between residents and relocation authorities, causing stress and difficulties finding replacement housing. Satisfaction with compensation was tied to perceptions of upward housing mobility, while dissatisfaction was influenced by perceptions of having been a victim of official graft. Expressed support for redevelopment projects was in the main grudging, and support for a project did not appear to greatly influence a positive disposition toward moving. Experiences connected with displacement are not monolithic, and neither are its outcomes. Householders forced to move may concede that relocation has had at once negative repercussions and benefits. Having achieved upward housing mobility or experienced improved quality of life subsequent to moving did not eradicate residents' wish to have been 'treated better,' monetarily or otherwise, by relocation officials. This oft-expressed desire calls attention to the need for greater awareness of, and sensitivity to, the nature of residential place attachment and the special problems of those forced to move.
539

Désorganisation du quartier de résidence et problèmes intériorisés chez les jeunes adolescents : le rôle modérateur du soutien parental

Décarie-Daigneault, Sarah January 2009 (has links)
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.
540

Pratiques et politiques sportives dans les quartiers sensibles : une approche monographique aux 3Cités à Poitiers / Sports pratices and policies in sensitive neighborhoods : A monographic approach at 3Cités, Poitier, France

Moussa, Kinda 29 January 2013 (has links)
Notre travail constitue une clef possible de lecture des multiples formes et pratiques contemporaines des sports, des loisirs sportifs et culturels dans un quartier populaire : les 3Cités, ville de Poitiers. Nous posons la question locale du quartier comme élément déterminant d'identification, de redéfinition des pratiques sportives et de requalification de l'espace public. Les pratiques sportives, mais aussi sociales et culturelles semblent inhérentes à la politique locale (les structures), municipale (la ville) et publique (l'Etat). À travers le champ des pratiques sportives et de loisirs, notre objet socio-anthropologique nous permet de comprendre dans quelle mesure le réaménagement des quartiers populaires, autrement dit, l'urbanisation de l'espace périphérique dans une ville de taille moyenne, favorise ou non, les objectifs politiques de mixité sociale, de désenclavement de l'espace, de cohésion sociale, d'intégration, de lutte contre la ségrégation sociale et d'égalité des chances. Une analyse sociodémographique de la population résidant dans un espace singulier, où cohabitent une souche française, française d'origine étrangère et étrangère, nous amène à comprendre l'évolution des formes et les attentes de la pratique sportive, mais aussi, le frein et le désengagement de cette même pratique. Nous portons une attention particulière à la pratique sportive féminine car les femmes semblent éloignées du milieu sportif à la fois institutionnel et non-institutionnel. Il s'agit de montrer en quoi la pratique féminine dans ce quartier sensible est liée aux choix du sport proposé ainsi qu'aux facteurs sociaux tels que la culture d'origine, les conditions socio-économiques et l'implication des parents dans le milieu sportif. / Our study is a one of the possible keys to understanding the various present-day types of sports activities and recreational and cultural sports practiced by the people living in the 3Cités, a working class neighborhood in Poitiers (France). We inquire about the role of the neighborhood as a defining element of identification which reshapes the pratice of sports activities and redevelops public space. Not only sports activities, but also social and cultural activities seem thus to depend both on local policies (involved in the availability of sporting facilities) and on the city and public policies. Taking into account the array of sports and recreational activities serves a socio-anthropological goal which allows us to understand whether and how the redevelopment of a working-class neighborhood (i.e. the urbanization of a peripheral space in a medium-sized city) contributes to the achievement of the political goals of integration, social mixity and cohesion. Also, we wonder whether or not this type of redevelopment may favor the struggle against geographical isolation and social segregation so as to foster equal opportunities for all. To answer these questions we provide a socio-demographical analysis of the population of an area where native-born French citizens share the space with French citizens of foreign origin and foreigners. This analysis allows us to address the two-fold issue of the evolution of the various types of sports activities and of the expectations connected with them. It is equally the opportunity to dicuss the factors impeding access to or leading to a lack of involvement in the pratice of sports activities. Consequently, we focus on the practice of sporting activities by females, since women seem to be less involved in sporting activities, in either institutional or unconventional contexts. We aim to explain how the pratice of sporting activities by females is influenced by the availability of sporting activities and by social factors such as native culture, socioeconomic living conditions ans parents' involvement in the sporting environment.

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