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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.
11

A Spatial Decision Support System for Optimizing the Environmental Rehabilitation of Borderlands

January 2013 (has links)
abstract: The border policies of the United States and Mexico that have evolved over the previous decades have pushed illegal immigration and drug smuggling to remote and often public lands. Valuable natural resources and tourist sites suffer an inordinate level of environmental impacts as a result of activities, from new roads and trash to cut fence lines and abandoned vehicles. Public land managers struggle to characterize impacts and plan for effective landscape level rehabilitation projects that are the most cost effective and environmentally beneficial for a region given resource limitations. A decision support tool is developed to facilitate public land management: Borderlands Environmental Rehabilitation Spatial Decision Support System (BERSDSS). The utility of the system is demonstrated using a case study of the Sonoran Desert National Monument, Arizona. / Dissertation/Thesis / M.A. Geography 2013
12

Trade-off analysis of forest ecosystem services – A modelling approach

Pang, Xi January 2017 (has links)
Forest is a resource that is increasingly utilized for multiple purposes. The balance between energy demands and the long-term capacity of ecosystems to support biodiversity and other ecosystem services is crucial. The aim of this project was to increase the knowledge on and to develop methods and tools for trade-offs and synergies analysis among forest ecosystem services based on different forest management policies. Paper I provides an overview of existing models for integrated energy-environment assessment. A literature review was conducted on assessment models and their ability to integrate energy with environmental aspects. Missing environmental aspects concern land use, landscapes and biodiversity. In Paper II a modelling framework was set up to link a landscape simulator with a habitat network model for integrated assessment of bioenergy feedstock and biodiversity related impacts in Kronoberg County. In Paper III we continued with the same management scenarios, while the analysis was expanded to five ecosystem services by developing the Landscape simulation and Ecological Assessment (LEcA) tool: industrial wood, bioenergy, forest carbon stock, recreation areas and habitat networks. In Paper IV we present two heuristic methods for spatial optimization – simulated annealing (SA) and genetic algorithm (GA) – to find optimal solutions for allocating harvest activities, in order to minimize the impacts on habitat networks. In Paper V, as response to the findings in Paper I, we linked the energy model MESSAGE with our LEcA tool for forest bioenergy demand assessment while applying environmental and transport restrictions, in a study of Lithuania. We found trade-offs between industrial wood production and bioenergy on one side, and recreation values, biodiversity, and to some extent carbon storage on the other side. The LEcA tool integrated forest simulation and management with assessment of ecosystem services, which is promising for integrated sustainability assessment of forest management policies. / <p>QC 20171023</p>
13

Multireservoir Systems Optimization : A New Approach

Sharma, G K 12 1900 (has links) (PDF)
No description available.
14

Enhancing equity in public transportation using geographic information systems and spatial optimization

Cha, Ho-Seop 11 September 2008 (has links)
No description available.
15

Evaluating the Effectiveness of Tree Locations and Arrangements for Improving Urban Thermal Environment

January 2017 (has links)
abstract: Trees serve as a natural umbrella to mitigate insolation absorbed by features of the urban environment, especially building structures and pavements. For a desert community, trees are a particularly valuable asset because they contribute to energy conservation efforts, improve home values, allow for cost savings, and promote enhanced health and well-being. The main obstacle in creating a sustainable urban community in a desert city with trees is the scarceness and cost of irrigation water. Thus, strategically located and arranged desert trees with the fewest tree numbers possible potentially translate into significant energy, water and long-term cost savings as well as conservation, economic, and health benefits. The objective of this dissertation is to achieve this research goal with integrated methods from both theoretical and empirical perspectives. This dissertation includes three main parts. The first part proposes a spatial optimization method to optimize the tree locations with the objective to maximize shade coverage on building facades and open structures and minimize shade coverage on building rooftops in a 3-dimensional environment. Second, an outdoor urban physical scale model with field measurement is presented to understand the cooling and locational benefits of tree shade. The third part implements a microclimate numerical simulation model to analyze how the specific tree locations and arrangements influence outdoor microclimates and improve human thermal comfort. These three parts of the dissertation attempt to fill the research gap of how to strategically locate trees at the building to neighborhood scale, and quantifying the impact of such arrangements. Results highlight the significance of arranging residential shade trees across different geographical scales. In both the building and neighborhood scales, research results recommend that trees should be arranged in the central part of the building south front yard. More cooling benefits are provided to the building structures and outdoor microclimates with a cluster tree arrangement without canopy overlap; however, if residents are interested in creating a better outdoor thermal environment, open space between trees is needed to enhance the wind environment for better human thermal comfort. Considering the rapid urbanization process, limited water resources supply, and the severe heat stress in the urban areas, judicious design and planning of trees is of increasing importance for improving the life quality and sustaining the urban environment. / Dissertation/Thesis / Doctoral Dissertation Geography 2017
16

Räumliche Optimierung der Bestandesstruktur unter Berücksichtigung von Einzelbaumeffekten

Herrmann, Isabelle 23 April 2014 (has links)
In dieser Dissertation werden erstmals Kenntnisse über ökologische Felder von Einzelbäumen mit Methoden der räumlichen Optimierung kombiniert, um ein Werkzeug zu schaffen, mit dem Empfehlungen für die Strukturierung von Beständen erarbeiten werden können. Dabei waren drei unterschiedliche waldbauliche Problemstellungen Ausgangspunkt der Arbeit. Die ausführliche Beschreibung der Probleme führte zur Ableitung eines allgemeinen Optimierungsproblems, das nach optimalen Stammverteilungsplänen bzgl. verschiedener, waldbaulicher Zielsetzungen sucht. Der erster Schwerpunkt war die mathematische Herleitung der Zielgrößen. Hierbei wurde die Idee der Einzelbaumeffekte und das Konzept der ökologischen Felder verwendet, um die Zielgrößen aus den Einzelbaumeffekten zu entwickeln. Der zweite Schwerpunkt umfasste die Suche nach einem geeigneten Optimierungsmodell, mit dem die Horizontalstruktur eines Bestandes basierend auf weitreichenden, stetigen Einzelbaumeffekten räumlich optimiert werden konnte. Der gegebene Überblick zum Stand der Forschung bzgl. der räumlichen Optimierung in der Forstwissenschaft zeigte auf, dass nur Teilaspekte des allgemeinen Optimierungsproblems bisher modelliert worden sind. Von den vier daraufhin neu entwickelten Optimierungsmodellen wurden ein kontinuierliches und ein diskretes Modells nach der Auswertung der Eigenschaften weiterverwendet. Die Bewertung von verschiedenen, vorgestellten Nachbarschaftsdefinitionen und Varianten von lokalen Suchverfahren, Meta- und Hybridheuristiken führte zur Verwendung von k-opt für das diskrete Optimierungsmodell, von Compass Search für das kontinuierliche Optimierungsmodell und von Threshold Accepting und Iterated Local Search für beide Modelle. Für alle drei Optimierungsprobleme wurden jeweils zwei Tests je Algorithmus mit einer in C++ implementierten Optimierungssoftware durchgeführt. Beim ersten Test sollten in kurzer Zeit wiederholt gute Lösungen berechnet werden, während im zweiten Test wesentlich mehr Funktionswertberechnungen zur Verfügung standen, um eine sehr gute Lösung zu erhalten. Die Auswertung der Testrechnungen zeigte, dass das diskrete Optimierungsmodell dem kontinuierlichen Modell außer bei einem geringen Bestockungsgrad des Bestandes vorzuziehen ist. Die Zielfunktionsdefinitionen hatten wesentlichen Einfluss auf die Lösungen, vor allem bei gegenläufigen Zielen. Sehr gute Lösungen wiesen dabei charakteristische Verteilungsschemata der Baumpositionen auf, die nur durch eine Optimierung und nicht durch das wiederholte, zufällige Verteilen von Bäumen gefunden werden konnten. Für das diskrete Modell lieferte Threshold Accepting vor 2-opt und Iterated Local Search fast immer die besten Ergebnisse. 4-opt war immer deutlich schlechter als die anderen Algorithmen. Threshold Accepting berechnete sowohl sehr schnell gute Lösungen und als auch die besten Lösungen, wenn eine intensive Suche mit sehr vielen Funktionswertberechnungen möglich war.
17

Exploring Spatial Optimization Techniques for the Placement of Flow Monitors Utilized in RDII Studies

Skehan, Christopher A. 31 August 2010 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The aging infrastructure of a wastewater collection system can leak, capture ground water, and capture precipitation runoff. These are some of the most common problems in many of today’s US collection systems and are often collectively referred to as Rain Derived Inflow and Infiltration (RDII or I/I). The goal of this study is to investigate such optimized methods and their potential to improve flow monitor placement, especially for RDII studies, and to improve upon Stevens (2005) methodology. This project adopts a methodology from the “facility location problem”, a branch of operations research and graph theory. Solutions to a facility location problem will be adapted and utilized within a transportation GIS application to determine optimal placement.

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