• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 42
  • 22
  • 7
  • 3
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 106
  • 106
  • 106
  • 106
  • 20
  • 20
  • 17
  • 15
  • 13
  • 12
  • 11
  • 11
  • 11
  • 9
  • 9
  • 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.
51

Using the Radial Basis Function Network Model to Assess Rocky Desertification in Northwest Guangxi, China

Zhang, Mingyang, Wang, Kelin, Zhang, Chunhua, Chen, Hongsong, Liu, Huiyu, Yue, Yuemin, Luffman, Ingrid, Qi, Xiangkun 01 January 2011 (has links)
Karst rocky desertification is a progressive process of land degradation in karst regions in which soil is severely, or completely, eroded. This process may be caused by natural factors, such as geological structure, and population pressure leading to poor ecosystem health and lagging economic development. Karst rocky desertification is therefore a significant obstacle to sustainable development in southwest China. We applied a radial basis function network model to assess the risk of karst rocky desertification in northwest Guangxi, a typical karst region located in southwest China. Factors known to influence karst rocky desertification were evaluated using remote sensing and geographic information systems techniques to classify the 23 counties in the study area from low to extreme risk of karst rocky desertification. Counties with extreme or strong karst rocky desertification risk (43.48%, nearly half of the study area) were clustered in the north, central and southeast portions of the study area. Counties with low karst rocky desertification (30.43%) were located in the west, northeast and southwest of the study area. The spatial distribution of karst rocky desertification was moderately correlated to population density.
52

Assessing Linkages Among Landscape Characteristics, Stream Habitat, and Macroinvertebrate Communities in the Idaho Batholith Ecoregion

Hill, Andrew C. 01 December 2010 (has links)
Understanding the composition of lotic communities and the landscape processes and habitat characteristics that shape them is one of the main challenges confronting stream ecologists. In order to better understand the linkages among landscape processes, stream habitat, and biological communities and to understand how accurately our measurements represent important factors influencing biological communities, it is important to test explicit hypotheses regarding these linkages. Increasing our understanding of aquatic communities in a hierarchical context and recognizing how well our measurements represent factors structuring aquatic communities will help managers better evaluate the influence of land management practices on aquatic ecosystems, direct conservation strategies, and lead to better assessments of ecological condition. In Chapter 2, we used spatial data, field-based habitat measurements, and macroinvertebrate community data to 1) examine the influence of landscape processes on two factors of stream habitat; maximum stream temperatures and fine sediment, and to 2) examine how well these landscape and habitat characteristics represent factors influencing gradients in macroinvertebrate community structure. The results of this study showed that spatially derived measurements may be effectively used to test hypotheses regarding landscape influences on stream habitat and that spatial data, used in conjunction with field measurements can provide important information regarding factors influencing gradients in biological communities. In addition, spatially derived measurements may provide the same or additional information regarding influences on community structure as field-based measurements, which suggests that further research should be done to assess how well our field measurements represent factors that are important in shaping stream communities. The objective of Chapter 3 was to compare how well single field measurements and a combination of indicator variables hypothesized to be components of a single ecological processes or concept, known as a latent variable, represent thermal stress and fine sediment influences on macroinvertebrate communities. Results from this study showed that both single and latent variables explained relatively the same amount of variation in macroinvertebrate community structure. This suggests that while latent variables may have a potential to better refine how we represent ecological factors, a better basis for defining a priori hypotheses is needed before these variables can provide any additional information compared to single habitat measurements.
53

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

Cha, Ho-Seop 11 September 2008 (has links)
No description available.
54

Green and Just? - Assessing the Socio-Spatial Distribution of Green Areas in Malmö

Wascher, Laura January 2012 (has links)
Malmö strives to become an attractive and sustainable city by 2030. Continued population growth is a major reason for the need to densify within the existing urban structures. But more inhabitants will also increase pressure on usage and demand for green spaces in the city. Green space is of importance for human well-being and health, especially in urban environments. However the importance of green space is being marginalised in current debate and urban planning, due to the intensive focus on densification. The relevance of green space as an environmental quality has neither been recognised sufficiently in discussions on environmental justice. Previous policy and research has not integrated the socioeconomic dimension when assessing green space distribution. Hence this case study aimed to investigate the socio-spatial distribution of green areas in Malmö. A theoretical framework was compiled including concepts on environmental justice, i.e. the equal distribution of environmental qualities among different social groups. Moreover concepts regarding access (public/private), distance (walkability) and size (utilisation) of green areas were considered. A quantitative analysis was conducted with secondary data. As no comprehensive data set covered more recent years, census data and spatial data from 2005 was used for further analysis. The data was processed and analysed with the help of a geographic information system (GIS). With this approach green space and green areas could be identified. Green areas were categorised according to the level of public access, the size and the respective recommended distances to homes. In addition several socioeconomic factors were extracted from the census data and visualised in GIS. Thus the least advantaged neighbourhoods that lacked various public green areas could be located. On the city level it could be identified that only 13% of the total land area were covered with public green areas, resulting in 46 sq m per inhabitant in 2005. In April 2011 the population of Malmö passed the threshold of 300 000. Assuming that the amount of green areas had not changed since 2005 (unlikely), every inhabitant would have had 38 sq m of public green area in 2011. Considering these numbers in a Swedish context reveals that Malmö is on the bottom line of green area provision. On the neighbourhood level the greatest deficit was found in the eastern parts of central Malmö (e.g. Ostervärn), covering a network of neighbourhoods further south (Norra Sofielund, Södra Sofielund, Almhög, Gullviksborg). In total 32 neighbourhoods were characterised by above average percentage of children, elderly, foreign born or population density. Moreover almost all neighbourhoods lacking green areas were characterised by below average income. The results showed evidence for inequalities in the distribution of green areas between different social groups. This poses an incentive for further investigations in the field of environmental justice and sustainable urban development. Issues like actual walking distance, barriers and safety, qualities of green spaces and user experiences should be investigated in future research. Noting that the data used in this study was from 2005, it is crucial to update and determine shifts in socio-spatial distribution of green areas in the city today. Whilst the population is still increasing, it is likely that even more green space has vanished in the 7 years since 2005. All these issues are essential for a good knowledge based planning of the green and just future of Malmö.
55

Integrating Geospatial Technologies into the Property Management Process of the Transportation Right-Of-Way

Ghanta, Neelima 26 March 2007 (has links)
Property Management, one functional area within Right-of-Way offices in state transportation agencies, is responsible for managing the property acquired for highway projects. These activities are data and document intensive and efficiency for performing them would be improved through the implementation of an information management system. Because of the geospatial nature of many of these activities, geographic information systems (GIS) would increase the effectiveness of this system. A literature review and survey were conducted to understand the current state of practice for the use of GIS and information management systems in Property Management. There is no identified comprehensive system that covers all Property Management activities. An initial step in developing a geospatially-enabled enterprise-level information management system, a logical model was developed. This included developing the business process diagram, business process models, and use case models based on the principles of systems engineering using the Computer Aided Software (CASE) Enterprise Architecture. Activities that would benefit from a geospatial component have been identified and included in the models. The developed models have been validated by working with PennDOT staff. The resulting model serves as a standard template for state transportation agencies and helps conceptualize the advantages of integration and interaction with other systems, and geospatial enablement prior to investment in an information management system. / Master of Science
56

Vulnerability as a multi-faceted phenomenon : a GIS-based data model for integrated development planning, environmental management and disaster risk reduction / Isak Dawid Jansen van Vuuren

Van Vuuren, Isak Dawid Jansen January 2015 (has links)
People and the surrounding environment are affected by development. In striving to improve their livelihoods, people have through their development activities and exploitation of natural resources contributed to the degradation of the environment. The environment is seen as the totality of the biosphere within which anthropological and ecological activities take place. These activities are influenced by forces of nature, and in some events referred to as hazards, which can cause disruption, injury and loss of life. This premise forms the basic concept of disaster, to which people and the environment react from a position of vulnerability. Vulnerability is multi-faceted construct that is primarily associated with social conditions. It relates to concepts of development planning and environmental management from a causal as well as a preventative perspective. Since disaster risk reduction has become the key focus of mankind’s reaction to disasters, the concept of vulnerability has also become a key focus for research, and has linked various research communities, particularly those involved in disaster risk management, climate change adaption and development research in a multi-disciplinary research environment. Socio-economic developments inspired mainly by the Second World War have since the 1940s focused research attention on development planning and disaster risk management. Hazards-based research made way for a focus on vulnerability research so as to reduce disaster risk. At the same time, an increased focus on development planning triggered a shift in philosophy away from a procedural rational planning approach to strategic, communicative planning. Disaster risk reduction along the lines of development planning has seen the emergence of a multi-disciplinary approach to vulnerability research. An apparent increase in disaster-related losses and environmental degradation has nonetheless changed people’s thoughts and alerted them to the unsustainability of the course of development. With the introduction of the Bruntland Report in 1987, the concept of sustainable development was introduced as a long-term environmental strategy. Sustainable development objectives have created a focus on the human–environment system and an understanding of relationships between anthropological and ecological entities. A special interest in spatial patterning and the geographic distribution of organisms has led to the development of landscape ecology as a study of spatial patterns and ecological processes. A need to capture environmental criteria in a computerised spatial database emerged in the 1960s, and gave rise to the development of geographic information systems (GIS) technology. GIS-based thinking about how the real world can be presented in various conceptualisations of data structures, led to the development of GIS science (GIScience). The latter was based on research by Michael Goodchild who seeks to redefine geographic concepts and their use in the context of geographic information systems. Hence GIS should be defined as a data-processing tool, as opposed to the popular view of a map-making tool. By approaching GIS from an information system perspective that includes the development of conceptual, logical and physical data models, a platform is provided for the integration of spatial-based disciplines such as development planning, environmental management and disaster risk management. A synthesis of the theoretical foundation of these three disciplines shows commonalities in terms of a multi-disciplinary approach, as well as a concern for the environment and for social upliftment based on sustainable development principles. They also share a strong spatial orientation, which provides for GIS technology to serve as an entry point for the integration of these disciplines. The aim of the current research was therefore to develop a GIS-based data model that would address the landscape-based relationships between spatial entities from a database design point of view. The model is founded on the principles of database design, specifically the concept of entity-relationship modelling. It also incorporates basic Boolean logic to identify the functioning of an entity in its landscape setting as either acceptable or unacceptable. This concept supports the analysis of environmental sensitivity and disaster risk from the level of small geographic units, thereby enabling vulnerability reduction efforts at a local scale. The research in hand was useful to define and investigate the theoretical grounding of development management, environmental management, disaster risk reduction and geographic information systems, as well as to identify their common focus areas. An analysis of GIS technology and the development of a data model provided a focus on database development as the key for providing an information-based entry point and integration of development management, environmental management, disaster risk management. A case study for an area near Richards Bay, where development affected a wetland by increased vulnerability to flooding, has proven the GIS-based data model to be valuable as a tool that can be implemented to reduce vulnerability through informed and improved planning practices. / PhD (Development and Management), North-West University, Potchefstroom Campus. 2015
57

Vulnerability as a multi-faceted phenomenon : a GIS-based data model for integrated development planning, environmental management and disaster risk reduction / Isak Dawid Jansen van Vuuren

Van Vuuren, Isak Dawid Jansen January 2015 (has links)
People and the surrounding environment are affected by development. In striving to improve their livelihoods, people have through their development activities and exploitation of natural resources contributed to the degradation of the environment. The environment is seen as the totality of the biosphere within which anthropological and ecological activities take place. These activities are influenced by forces of nature, and in some events referred to as hazards, which can cause disruption, injury and loss of life. This premise forms the basic concept of disaster, to which people and the environment react from a position of vulnerability. Vulnerability is multi-faceted construct that is primarily associated with social conditions. It relates to concepts of development planning and environmental management from a causal as well as a preventative perspective. Since disaster risk reduction has become the key focus of mankind’s reaction to disasters, the concept of vulnerability has also become a key focus for research, and has linked various research communities, particularly those involved in disaster risk management, climate change adaption and development research in a multi-disciplinary research environment. Socio-economic developments inspired mainly by the Second World War have since the 1940s focused research attention on development planning and disaster risk management. Hazards-based research made way for a focus on vulnerability research so as to reduce disaster risk. At the same time, an increased focus on development planning triggered a shift in philosophy away from a procedural rational planning approach to strategic, communicative planning. Disaster risk reduction along the lines of development planning has seen the emergence of a multi-disciplinary approach to vulnerability research. An apparent increase in disaster-related losses and environmental degradation has nonetheless changed people’s thoughts and alerted them to the unsustainability of the course of development. With the introduction of the Bruntland Report in 1987, the concept of sustainable development was introduced as a long-term environmental strategy. Sustainable development objectives have created a focus on the human–environment system and an understanding of relationships between anthropological and ecological entities. A special interest in spatial patterning and the geographic distribution of organisms has led to the development of landscape ecology as a study of spatial patterns and ecological processes. A need to capture environmental criteria in a computerised spatial database emerged in the 1960s, and gave rise to the development of geographic information systems (GIS) technology. GIS-based thinking about how the real world can be presented in various conceptualisations of data structures, led to the development of GIS science (GIScience). The latter was based on research by Michael Goodchild who seeks to redefine geographic concepts and their use in the context of geographic information systems. Hence GIS should be defined as a data-processing tool, as opposed to the popular view of a map-making tool. By approaching GIS from an information system perspective that includes the development of conceptual, logical and physical data models, a platform is provided for the integration of spatial-based disciplines such as development planning, environmental management and disaster risk management. A synthesis of the theoretical foundation of these three disciplines shows commonalities in terms of a multi-disciplinary approach, as well as a concern for the environment and for social upliftment based on sustainable development principles. They also share a strong spatial orientation, which provides for GIS technology to serve as an entry point for the integration of these disciplines. The aim of the current research was therefore to develop a GIS-based data model that would address the landscape-based relationships between spatial entities from a database design point of view. The model is founded on the principles of database design, specifically the concept of entity-relationship modelling. It also incorporates basic Boolean logic to identify the functioning of an entity in its landscape setting as either acceptable or unacceptable. This concept supports the analysis of environmental sensitivity and disaster risk from the level of small geographic units, thereby enabling vulnerability reduction efforts at a local scale. The research in hand was useful to define and investigate the theoretical grounding of development management, environmental management, disaster risk reduction and geographic information systems, as well as to identify their common focus areas. An analysis of GIS technology and the development of a data model provided a focus on database development as the key for providing an information-based entry point and integration of development management, environmental management, disaster risk management. A case study for an area near Richards Bay, where development affected a wetland by increased vulnerability to flooding, has proven the GIS-based data model to be valuable as a tool that can be implemented to reduce vulnerability through informed and improved planning practices. / PhD (Development and Management), North-West University, Potchefstroom Campus. 2015
58

Simulação do balanço e transporte de nitrogênio e fósforo provenientes de dejetos animais aplicados em áreas agrícolas - estudo de caso: bacia do Rio Toledo - Paraná - Brasil. / Simulation of balance and transport of nitrogen and phosphorus from manure applied in agricultural areas - case study: Toledo river watershed - Paraná - Brazil.

Malta, Luiz Ricardo dos Santos 01 June 2009 (has links)
O presente trabalho apresenta um modelo computacional que visa servir de apoio ao processo de licenciamento de áreas para criação intensiva de animais. Trata-se de um modelo que descreve o comportamento do nitrogênio e do fósforo, oriundos da aplicação em solos agrícolas de dejetos da criação de animais e seu impacto nas bacias hidrográficas. Este modelo apóia-se em um Sistema de Informações Geográficas (SIG) e foi utilizado o ambiente ARCVIEW. O modelo define a quantidade de nitrogênio e de fósforo que ficam disponíveis no solo para serem arrastados pelo escoamento superficial para os corpos hídricos. Para tal, o modelo utilizará um balanço de massa destes nutrientes (entradas: por adubação orgânica, resultante dos dejetos de animais da bacia, adubação inorgânica, deposição atmosférica e fixação do nitrogênio) e (saídas: por remoção pela cultura, volatilização, desnitrificação, lixiviação e escoamento superficial). Sendo as perdas por lixiviação e escoamento superficial consideradas como as disponíveis nos solos para serem carreadas para os corpos hídricos. Em seguida o modelo define o escoamento da água pela bacia, ou seja, uma modelagem hidrológica. Finalmente, o modelo irá predizer o que resultará do transporte dos nutrientes disponíveis apoiando-se em modelagem hidrológica. O resultado disto será mostrado em um mapa de concentração acumulado ao longo da bacia. O estudo de caso será aplicado em áreas de suinocultura na bacia hidrográfica do Rio Toledo no Estado do Paraná, Brasil. Os resultados observados foram coerentes com os obtidos no monitoramento realizado em dois pontos da bacia de estudo. / This work presents a computer-programmed model, which aims to aid environmental agencies in issuing licenses regarding hog farms. It helps to describe the nitrogen and phosphorus behavior impacts in a watershed, when manure is applied in the soil. The algorithm is programmed on a Geographic Information Systems (GIS) tool ARCVIEW. The model defines the amount of nitrogen and phosphorus that remains available in the soil to be transported by runoff. The model calculates the balance of all nitrogen and phosphorus sources (organic and inorganic fertilizers, atmospheric accumulation and nitrogen fixation) and losses (plants use, volatilization and denitrification, soil lixiviation and runoff). The result of this balance is the amount of these elements available to be transported along of the watershed. A hydrological simulation model is used to calculate the runoff. The final result is a nitrogen and phosphorus concentration map, accumulated along the basin. The case study to test the model is the Toledo River, state of Paraná, Brazil due to its high concentration of hog farming. The model was able to reproduce data observed in this basin.
59

Habitat fragmentation and the southern brown bandicoot Isoodon obesulus at multiple spatial scales

Paull, David James, Physical, Environmental & Mathematical Sciences, Australian Defence Force Academy, UNSW January 2003 (has links)
This thesis investigates the process of habitat fragmentation and the spatial and temporal scales at which it occurs. Fragmentation has become an important topic in biogeography and conservation biology because of the impacts it has upon species??? distributions and biodiversity. Various definitions of fragmentation are available but in this research it is considered to be the disruption of continuity, either natural or human-induced in its origins and operative at multiple spatial scales. Using the distribution of the southern brown bandicoot Isoodon obesulus as a case study, three spatial scales of fragmentation were analysed. At the continental scale, the Australian distribution of the subspecies I. o. obesulus was examined in relation to climate, geology and vegetation cover at the time of European settlement of Australia and two centuries later. Using archived wildlife records and Geographic Information Systems (GIS) analyses, habitat suitability models were created to assess natural and human-induced fragmentation of the distribution of I. obesulus in 1788 and 1988. At the regional scale, a study was made of the distribution of I. obesulus in the south-east of the State of South Australia. Again, natural and human-induced patterns of habitat fragmentation were modelled using GIS with climate, soil and vegetation data for the time of European settlement and at present. At the local scale, the distribution of I. obesulus was the subject of a detailed field survey of 372 sites within 29 remnant patches of native vegetation in south-eastern South Australia in order to understand the variables that cause habitat fragmentation. Geographic information systems were used again but in a different way to carefully stratify the field survey by overlaying maps of topography, vegetation and past fires. The large dataset collected from the surveys was described using six generalized linear models which identified the significant variables that fragment the distribution of I. obesulus at a local scale. From the results of the field surveys, a subset of four remnants was chosen for further GIS spatial modelling of the probability of I. obesulus occurring within remnants in response to fire via a controlled burning programme put in place to reduce accumulating fuel loads. These investigations show that habitat fragmentation can be caused by different factors at different spatial scales. At the continental scale, it was found that climate played a dominant role in influencing the fragmented distribution of I. obesulus but vegetation change during the past two centuries has also had a profound impact on the availability of habitat. Within south-eastern South Australia, the species??? regional scale distribution is constrained by climate and also by soil and vegetation patterns. Dramatic change to its regional distribution occurred in the 20th century as a result of the clearance of native vegetation for planting pastures, crops and pines. Fragmentation at the regional scale has resulted in the remaining habitat being reduced to small, isolated, remnant patches of native vegetation. At the local scale it was found that variables which disrupt the continuity of I. obesulus habitat within remnants include vegetation cover in the 0-1 m stratum, abundance of Xanthorrhoea australis and soil texture. For a subset of sites located in one landsystem of the study area, named Young, the age of vegetation since it was last burnt was also found to be a significant variable, with vegetation 10-14 years old since burning providing the most suitable habitat. Spatial modelling of two scenarios for prescribed burning over 15 years revealed that the use of fire as a habitat enhancement tool will be complicated and require a detailed understanding of the factors that cause natural fragmentation in the distribution of I. obesulus at the local scale. A further conclusion of the study was that ecological relationships between species and their habitats require careful interpretation of multi-scaled datasets and conservation plans for endangered species ought to be made at multiple spatial scales. Future research directions are identified including the linking of multi-scaled habitat fragmentation models to genetic studies of the species throughout its range.
60

地理資訊系統在不動產查詢與分析上之應用

王琬宜, Wang, Wan-I Unknown Date (has links)
本研究整合不動產相關之資訊及相關之空間資料,以使用者的觀點,利用地理資訊系統輔助建立一套結合不動產本身條件及其空間關係的不動產查詢分析系統。 本研究所開發之不動產查詢分析系統,在地理資料庫之建置上採用ARC/INFO軟體,納入了購屋考量之基本屬性因素及空間環境屬性因素,以兼顧不動產之「點」及「面」的資訊。系統的開發則採用Visual Basic(VB) 6.0中文企業版。 本系統在開發上未使用任何商業地理資訊系統軟體,而是以Visual Basic撰寫程式方式開發完成,除了具有開發使用之載台成本低廉,工具取得容易等優點外,其最大的效益在於系統的可攜性及可推廣性。本系統最大之功能特色在於使用者可自行選擇所需的個案條件,以及依據其對各因素之重視程度自行決定各因素之權重。

Page generated in 0.1351 seconds