Refine
Document Type
- Doctoral thesis (8)
- Conference proceeding (1)
- Master thesis (1)
- Report (1)
Has Fulltext
- yes (11)
Is part of the Bibliography
- no (11)
Keywords
- Geoinformationssystem (11) (remove)
With the increasing consciousness of the value of wetland ecological and environmental functions and its fast rate of decline in the size of this important and rich ecosystem globally, the Niger Delta ecosystem has been reported to be undergoing tremendous change, hence the need for this research, to identify the challenges and proffer solutions. This study focuses on ascertaining if a change has occurred in the Upper Orashi Forest Reserved wetland, to know and evaluate the policies used in managing the wetland in the region and Nigeria. To ascertain the wetland change, land cover change detection was carried out using Geographic Information Systems and Remote Sensing to produce paradigm or data to detect change occurrence in the wetland area. Supervised classification of land use and land cover change was carried out using LANDSAT data from 2002, 2008, and 2019. Thereafter, the land cover transition was mapped for the period 2002 to 2019 and this was computed for the net land cover change for the period of study. The site was classified into three different classes and each class was analyzed using the land use and land cover change model formula. The result from this part shows that there is a consistent decrease in the wetland area for the period under review and in the other two identified classes, some interchangeable compositions were observed for the period of study. To validate this result, the opinion of experts and the host community is needed. Two sets of questionnaires were designed for experts and local community dwellers to sample their opinion in relation to the wetland and its management. The information collected was analyzed using Microsoft excel and the result shows that changes have occurred in the wetland of Upper Orashi Forest (decrease in size and other challenging issues with respect to policies and regulations). This study has identified critical challenging issues facing wetlands in the region or driving factors of wetland loss in the study area. Thereafter making recommendations that will help address these issues to actualize environmental sustainability and sustainable wetland in the region and Nigeria at large.
Accra and Kumasi are the two major cities in Ghana. Spatial urban expansion has been experienced in transforming different non-urban Land Use Land Cover (LULC) types into urban/built-up areas with a potential direct relationship to temperature rise in the cities. Thus, this dissertation aims to establish the relationship between urban spatial expansion and temperature in Accra and Kumasi metropolis. Multi-source datasets such as remote sensing images, different GIS vector layers, reference maps and historical temperature datasets were used for this retrospective study. This research was grouped under three components: environmental science, environmental technology, as well as environmental management and planning. From the environmental science component, LULC maps were produced for different years to assess the trend of temporal change in the various LULC classes in the two metropolises. Remote sensing indices and land surface temperature were retrieved from the remote sensing images to determine their correlations. Temperature time series was analysed by calculating temperature indices and determining temporal trends to reveal changes in air temperature to detect urban warming and its impacts. From the environmental technology, the novel random forest algorithm was utilised to classify the satellite images of both cities since previous works have utilised other traditional classifiers. The satellite imageries were used for point-based estimation of temperature to determine Urban Heat Islands (UHIs) hotspots. For environmental management and planning, spatial urban expansion techniques were utilised to ascertain trends in urban/built-up areas, especially in both cities' sub-metropolitan zones. For prescient purposes, future LULC modelling was implemented to provide insights into the proportions of the various LULC changes in 2025. The analysis identified two salient findings: increased urban/built-up areas at the expense of agricultural and forestlands throughout the study period and the positive correlation between spatial urban expansion and temperature. This indicated warming up of urban temperature in both cities. The major findings in this dissertation provided evidence of how integrated datasets and research techniques can be utilised for LULC changes to determine the relationship between spatial urban expansion and temperature at local scales. Institutions such as metropolitan assemblies and policymakers may adopt the concepts demonstrated in this work to rapidly assess urban environments and investigate the relationship between spatial urban expansion and temperature.
Agentenbasierte Modellierung und Simulation der Rettungskette : eine Fallstudie in der Lausitz
(2022)
Ein funktionierender Rettungsdienst ist für die Gesellschaft von zentraler Bedeutung, da in medizinischen Notsituationen die Gesundheit eines Verunfallten von der Qualität der praäklinischen medizinischen Versorgung abhängt. Dabei steht man vor immer neuen Herausforderungen des sozioökonomischen Wandels und technischen Fortschritts, die neue Ansätze zur Systemoptimierung erfordern. Diese Arbeit beinhaltet eine Literaturübersicht über Planungsprobleme, sowie eine Klassifizierung von Emergency Medical Service (EMS) Systemen. Ein agentenbasiertes Simulationsmodell für ein notarztbasiertes EMS-System wird vorgestellt und auf die Rettungskette eines städtischen Gebietes Cottbus, Brandenburg, Deutschland angewandt. Die Parametrisierung des Modells erfolgt durch zugrundeliegende Einsatzdaten, dabei wird ein Geoinformationssystem (GIS) genutzt, Notrufe über die Bevölkerungsdichte mit einer zeitabhängigen Rate generiert und statistische Kenngrößen des Systems ausgewertet. Das in AnyLogic implementierte Simulationsmodell enthält eine graphische Nutzeroberfläche, in der Einsatzdetails und Statistiken als Grundlage für Anwendungen in der Praxis angezeigt werden.
Die Konstruktionsplanung von neuen Transitrouten oder Energieleitungen auf einem topografischen Gelände wird von Ingenieuren in der Regel manuell vorgenommen, ohne dass eine Optimalität garantiert werden kann. Wir stellen einen neuen Ansatz zur Berechnung von Trajektorien für die Entwicklung neuer optimaler Transitrouten und Energieleitungen zwischen zwei Standorten auf einer Untermannigfaltigkeit U von IR³ vor. Diese Untermannigfaltigkeit repräsentiert die Topographie eines Geländes. U wird näherungsweise durch ein spezielles gewichtetes Gitternetz modelliert. Auf diesem Gitternetz werden die kürzesten Wege für den Bau neuer Routen bestimmt, wobei wir drei Optimierungskriterien betrachten werden: Routen mit minimaler Länge, Routen mit geringsten Baukosten und Routen mit minimalen absoluten Höhenvariationen oder minimalen absoluten Steigungen. Anschließend wird eine Kombination dieser Kriterien gebildet, um dieses Problem zu einem multikriteriellen Optimierungsproblem zu erweitern. Ein Algorithmus für den kürzesten Weg, wie der Dijkstra-Algorithmus, wird verwendet, um optimale Kompromisse für die Konstruktion neuer Routen zu berechnen.
Planning the construction of new transport routes or power lines on terrain is usually carried out manually by engineers, with no guarantee of optimality. We introduce a new approach for the computation of an optimal trajectory for the construction of new transit routes and power lines between two locations on a submanifold U _ R3 representing the topography of a terrain. U is approximatively modeled by a special weighted grid. On this grid, the shortest paths for the construction of new routes are determined, whereby we consider three optimization criteria: routes with minimum distance, routes with lowest construction costs and routes with minimum absolute altitude variations or minimum absolute gradients. Subsequently, a combination of these criteria is used to expand this problem into a multi-criteria optimization problem. A shortest path algorithm, such as the Dijkstra algorithm, is used to compute optimal compromises for the construction of new routes.
Dieser Band umfasst die Vorträge eines Workshops, der im Rahmen des DBU-Projekts „Bewahrung von vorindustriellen Meilerstandorten in Brandenburg – Ein Beitrag zur modellhaften Sicherung und nachhaltigen Nutzung einer durch anth-ropogene Umwelteinflüsse gefährdeten historischen Kulturlandschaft“ am 19. Februar 2019 an der BTU in Cottbus durchgeführt wurde. Ziel des DBU-Projekts ist es, vorindustrielle Meilerstandorte im Land Brandenburg möglichst flächenhaft zu erfassen und deren Denkmalwert zu ermitteln, um einen Beitrag zum Schutz dieser bisher kaum beachteten Bestandteile der historischen Kulturlandschaft zu leisten. In der Modellregion Niederlausitz wird ein auf GIS-Methoden basiertes Verfahren entwickelt, mit dessen Hilfe Strategien und Konzepte erarbeitet werden, die auch in anderen Regionen die Bewahrung historischer HKM-Landschaften und anderer vorindustrieller Kulturlandschaftsrelikte erlaubt. Wesentliches Element des Verfahrens ist eine Musteranalyse, mit der das Mosaik an HKM-Standorten und die Bezüge ganzer HKM-Gruppen zu weiteren Kulturrelikten und v. a. auch Hinterlassenschaften der historischen Landnutzung dargestellt werden. So lassen sich Kategorien für die Schutzwürdigkeit einzelner Standorte oder ganzer HKM-Areale ableiten, auf deren Grundlage die Ausweisung von Schutzgebieten erfolgen kann. Aufgrund der Zusammenarbeit von Behörden und einer Universität sowie durch die Einbindung lokaler und regionaler Akteure der unterschiedlichen Fachdisziplinen können hier Nutzungs- und Interessenkonflikte im Schnittbereich von Denkmal-, Natur- und Umweltschutz praxisnah vermieden werden. Die Beiträge in diesem Tagungsband reichen von aktuellen Ergebnissen der Meilerforschung bis hin zu denkmalpflegerischen Aspekten und bilden eine wichtige Grundlage für die Diskus-sion in dem o.g. DBU-Projekt.
Improvement of flood risk assessment under climate change in Ho Chi Minh City with GIS applications
(2014)
Ho Chi Minh City is the largest city in VN. The city is the most important center of economy, society and culture in the southern region of Vietnam. However, due to characteristics of natural conditions with low topography and borders touch the sea so that since the late 20th century with the rapid economic and urban development there are environmental problems have arisen. One of the problems is flooding issue caused by high tide. With these natural conditions and sea level rise of climate change in the future, Ho Chi Minh City is considered as one of the most affected and damaged cities in the world.
Therefore, many policies have been set out from the national to local levels in Vietnam to prepare for adaptability of impacts and risks of the sea level rise and the climate change. And this has also been considered in Ho Chi Minh City as the development policies of the city authorities have to consider in the context of the sea level rise and the climate change. A number of researches have been conducted to assess the impact of climate change to Ho Chi Minh City in the future. However, these researches are still need to be enhanced further.
The flooding problem is a major issue of the sea level rise in Ho Chi Minh City. And to make a good result, the flood model needs a lot of requirements that ensure fine quality of input data, suitable model and a relied procedure. In the available research, the input data is not really the highest quality in the available context in Ho Chi Minh City. As the flood model is implemented, one of the input data requirements of the model is information detail of elevation in the flooded area. And this is more necessary than in geophysical urban areas such as Ho Chi Minh City. And to assess fully flood risk issues for flooding caused by tidal phenomenon in Ho Chi Minh City, the determination of many characteristics of flood model is very useful for users who need to apply the results of the model for the planning development in Ho Chi Minh City in the future. Besides adopting a uniform environment as GIS for managing all the data of flooding problem and making conditions for the development of decision support systems is very necessary for flood management in the future.
The research has been carried out and its results have been generated on the flood risk assessment associated context of the sea level rise due to climate change with high emissions scenario A1FI in 2030 for the current houses, the population and the land use types. The results have shown a lot of the areas where are inundated in the future with the increasing flooding duration, depth and frequency even though they are not flooded at the current because there are some protective structures. This will be helpful for suggesting a forecast of the development direction to decision makers in Ho Chi Minh City for next time period.
And the last part is the proposal for decision and policy makers, authorities and planners as well. Moreover, the results of this research can be used as the references and the foundations for further researches and so that the problems that Ho Chi Minh City may be encountered due to flood risk caused by climate change to the economic and social aspects of the development in Ho Chi Minh City will encounter. And the problem of adaptation to climate change will be more completed and more thoroughly so that it is to minimize the damage of climate change for the city.
Urban morphology is used in many developed countries to classify and manage the dis-tribution of urban functions. In urban planning, it helps to identify the emerging prob-lems and solve the disorder of urban functions. The megacity Ho Chi Minh City has faced many problems with uncontrollable urbanization, urban management and plan-ning. It has received increasing tropical storms and cyclones which caused more heavy rains in recent decades. Rapid urbanization has caused the increase of built-up coverage with disordered typologies, incomplete infrastructure and urban-peripheral instability. In the flooding context, these problems have increased more seriously with flooding impacts and caused uncontrollable planning and management in the city. This study applies the urban morphology method to measure flood impacts on urban functions and develop the adaptive solutions for flooding adaptation for Ho Chi Minh City. The methods in this study are based on applying fractal geometry, GIS and Remote Sensing on large-scale maps for measuring the urban morphology. The land-use map and the building footprints map of 2010 were founded to analyze the distribution of urban areas by high resolution of satellite images and large scale GIS data. The fractal geometry was a setting based on Avenue program of Arcview GIS to measure the urban morphology. This formed a key input for the multi-criteria analysis (MCA) method that investigated the cause of flood impacts and suggested the solution for flooding adapta-tion. In addition, alterations of lakes, ponds and watercourse from 1995 to 2009 were explored. The study showed HCMC had problems on irrational development in residential densi-ties areas and urban functions, and the uneven development of population and residen-tial density between the urban areas: too much in the urban districts (about 300 to 500 persons per hectare per block and coverage ratio 0.7 - 0.9). This pushed the increasing demand on built-up area and filled-up rivers and canals (About 80 percent of original ponds and lakes in inner-center were filled-up in the past; and 63 percent of ponds and lakes have been filled-up in Sub-Districts and new-urban-development areas). It made the imbalance between the permeability of land surface and the run-off water flows; then leads the inundation to increase. This is the main reason for reducing the water-storage capacity in rainy season. Flooding in urban residential area was more im-pacted than in rural residential area, higher level and longer flood time; while flooding in the rainy season due to high tides, heavy rains or both was the emerging and uncon-trollable problems. For flooding adaptation, urban morphology analysis helped to figure out the potential areas in the city could be used for reducing flooding impacts in urban areas. There are many low-density residential areas in above 1.5 meter AMSL areas in the North, Northwest and Northeast areas of the city which could be developed with complete infrastructure and urban services to attract people from high-density residential areas impacted deeply by floods in the center. These potential areas could be the long-term strategic solution to flooding adaptation for HCMC. The results also suggested that some current flooded areas would be re-planned or returned to be the water-storage and permeable areas (such as green parks, ponds and lakes). This re-planning would improve the city landscape and increase the permeable surface, green spaces and open spaces to HCMC. More green spaces, lakes and ponds will also help to reduce the temperature of urban center in the dry season. This adaptation solution would reduce at least 25 percent of current flooded areas in urban center. The protection and constructed restriction of current agricultural areas in peri-urban Districts would maintain the infil-tration and green-tree areas. Furthermore, the complete drainage system would help to reduce better flood for these areas. Finally, fully dredging river and canal system of the city would reduce about 25 to 30 percent of current flooded areas.
Historically as a city situated in a low-lying area a Ho Chi Minh City has been exposed to floods. Ho Chi Minh City is a megacity with uncontrollable urbanization and dynam-ic economies. In recent years, flood has become a serious problem with a multitude of follow-on impacts. It received more heavy rains affected by tropical storms and cy-clones. Further urbanization and future changes in climate are likely to increase flood risks. People have faced the flood impacts on the socioeconomic aspects in recent dec-ades. This study researched on 450 households in different spaces of the inner center (old districts), developed center (urban districts) and new-developing areas (peri-districts) and in different geographical elevations to identify the impacts of flooding in various space and time; and various problems on households’ socioeconomic aspects in flood residential areas. The multi-criteria analyses in GIS and with of the combination SPSS analysis, the sur-veyed households were identified by their location on the topographic map to clarify the flooding reasons and the types of flood in the areas. The 450 households were chosen in flood residential areas and selected in three categories of characteristics: (1) 150 poor households in flood housing areas; (2) 150 poor households in non-flood housing areas; and (3) 150 higher-income households in non-flood housing areas. This disparity was to analyze the different flood impacts on socioeconomic aspects and on household capitals amongst them. The linear regression in SPSS analysis was used to clarify the relation-ships between flood types with space factor (geographical elevation) and time factors (flood months in year, and flood years in residential areas). This test gave the supports to the reliability of the study results. By geographical elevation analysis, flood impacted on the areas in three main types: (1) flood by rain; (2) flood by tide; and (3) flood by both rain and tide. The tidal flood oc-cupied the low-elevation areas; flood by rain invaded the widespread higher-elevation areas; and the mix type of flood occupied the transition areas between flood areas by rain and by tide. Lower land had the deeper flood level, however; many of high-land areas were flooded in this city. Flood in residential areas had caused flood problems on streets, sidewalks (housing pavements), residential drainage system, water supply and electric power. In the poor households of Group One, flood in residential areas impacted their housing areas. To protect housing from flooding, many households had to invest their income for house rising or rebuilding or pavement rising, etc. They also privately invested for repairing or new buying their housing facilities, furniture and other appli-ances. Their income was lost and deficit. To the household capitals analysis, households were impacted more on physical, financial, natural and human capitals. The poor households in Group One had the most vulnerabilities amongst three groups, whilst there was no support from social organizations and government at levels. The household strategies developed in this study are to support people in flood and flood-prone areas conserving their capabilities to achieve the strategic outcome for sustainable develop-ment.
Human influence on the biosphere has transformed natural land cover (LC) into modified LC. Shifting focus from individual species study to large-scale assessment is therefore needed to restore the damaged ecosystem. The hypotheses were: (a) the post-mining landscapes are getting more diverse over time (b) GIS, remote sensing and patch analyst can generate LC information and landscape characterization statistics for assessing habitat diversity and monitoring land cover change (LCC) in a disturbance-dominated area (c) relationship exist between habitat diversity and field based species richness/LCC and environmental conditions/LCC and biodiversity losses. The general aims of this research were (a) to assess the impact of disturbance on LCC and habitat diversity (b) to identify how accurately patterns of habitat diversity, complexity, fragmentation, primary production and LCC can be assessed or predicted with GIS and remotely sensed data. LC maps of 1988, 1991, 1995, 1998, 2000 and 2003 were produced from LANDSAT TM images of Schlabendorf Nord and Schlabendorf Süd. These images were used to survey the changing landscape. After classifying the images based on dominant land cover types, the area and perimeter of all patches were defined. Landscape characterization metrics were generated using patch analyst. LCC statistics were estimated for each LC map year. Change detection extension was used to identify changes among vegetation or land cover types into “negative change”, “no change” and “positive change”. DCA ordination technique (CANOCO) was used to study similarity among the distribution of land cover types. Other relevant analysis made include soil pH analysis and climate data evaluation. The outcome of the research shows that the process of LCC takes place at the interface between environmental and human systems. Land cover transformations in most cases in Schlabendorf were as a result of progressive and reversed plant succession. Overall changes in both landscapes showed increased area of pine afforestation, deciduous trees afforestation, lake and mixed grassland with trees. The LCC s were predominantly caused by harvesting of afforested pine, restoration related construction activities or other land cover management practices, reverse succession, low soil pH especially along the path of the mine strip, loss of soil fertility, human decisions and policies. There was increase in habitat richness, heterogeneity, fragmentation, and shape complexity due to decrease in habitat size, increased land use intensity etc. Lower habitat diversity in Schlabendorf Süd was due to the comparatively large landscape area, high patch number and higher habitat richness in most cases which confirms the claim that relationship between habitat diversity and habitat heterogeneity varies according to scale (Tews et al., 2004). Increase in biomass accumulation particularly in Schlabendorf Süd contributed to the exchanges for greenhouse gases between the forest cover, soil and the atmosphere, hence changing the climatic condition on terrestrial ecosystems, biodiversity and LCC. Unlike Schlabendorf Nord, Schlabendorf Süd still undergoes more active reclamation activities resulting in less similarity between the two post-mining landscapes over time. Within a given ecosystem, any change in habitat diversity can change the number of species in the resulting habitats types, in other words habitat diversity can be used to predict the species richness in a given ecosystem. The approach to this work provides a beneficial trade off between expensive ground vegetation or LCC survey and low-priced image processing analysis. It requires less manpower and less time but greatly reliable for assessing LCC, habitat diversity/richness and heterogeneity in large inaccessible areas such as dunes in post-mining landscape.