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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.
261

On the development of decision-making systems based on fuzzy models to assess water quality in rivers

Ocampo Duque, William Andrés 17 April 2008 (has links)
There are many situations where a linguistic description of complex phenomena allows better assessments. It is well known that the assessment of water quality continues depending heavily upon subjective judgments and interpretation, despite the huge datasets available nowadays. In that sense, the aim of this study has been to introduce intelligent linguistic operations to analyze databases, and produce self interpretable water quality indicators, which tolerate both imprecision and linguistic uncertainty. Such imprecision typically reflects the ambiguity of human thinking when perceptions need to be expressed. Environmental management concepts such as: "water quality", "level of risk", or "ecological status" are ideally dealt with linguistic variables. In the present Thesis, the flexibility of computing with words offered by fuzzy logic has been considered in these management issues. Firstly, a multipurpose hierarchical water quality index has been designed with fuzzy reasoning. It integrates a wide set of indicators including: organic pollution, nutrients, pathogens, physicochemical macro-variables, and priority micro-contaminants. Likewise, the relative importance of the water quality indicators has been dealt with the analytic hierarchy process, a decision-aiding method. Secondly, a methodology based on a hybrid approach that combines fuzzy inference systems and artificial neural networks has been used to classify ecological status in surface waters according to the Water Framework Directive. This methodology has allowed dealing efficiently with the non-linearity and subjective nature of variables involved in this classification problem. The complexity of inference systems, the appropriate choice of linguistic rules, and the influence of the functions that transform numerical variables into linguistic variables have been studied. Thirdly, a concurrent neuro-fuzzy model based on screening ecological risk assessment has been developed. It has considered the presence of hazardous substances in rivers, and incorporates an innovative ranking and scoring system, based on a self-organizing map, to account for the likely ecological hazards posed by the presence of chemical substances in freshwater ecosystems. Hazard factors are combined with environmental concentrations within fuzzy inference systems to compute ecological risk potentials under linguistic uncertainty. The estimation of ecological risk potentials allows identifying those substances requiring stricter controls and further rigorous risk assessment. Likewise, the aggregation of ecological risk potentials, by means of empirical cumulative distribution functions, has allowed estimating changes in water quality over time. The neuro-fuzzy approach has been validated by comparison with biological monitoring. Finally, a hierarchical fuzzy inference system to deal with sediment based ecological risk assessment has been designed. The study was centered in sediments, since they produce complementary findings to water quality analysis, especially when temporal trends are required. Results from chemical and eco-toxicological analyses have been used as inputs to two parallel inference systems which assess levels of contamination and toxicity, respectively. Results from both inference engines are then treated in a third inference engine which provides a final risk characterization, where the risk is provided in linguistic terms, with their respective degrees of certitude. Inputs to the risk system have been the levels of potentially toxic substances, mainly metals and chlorinated organic compounds, and the toxicity measured with a screening test which uses the photo-luminescent bacteria Vibrio fischeri. The Ebro river basin has been selected as case study, although the methodologies here explained can easily be applied to other rivers. In conclusion, this study has broadly demonstrated that the design of water quality indexes, based on fuzzy logic, emerges as suitable and alternative tool to support decision makers involved in effective sustainable river basin management plans. / Existen diversas situaciones en las cuales la descripción en términos lingüísticos de fenómenos complejos permite mejores resultados. A pesar de los volúmenes de información cuantitativa que se manejan actualmente, es bien sabido que la gestión de la calidad del agua todavía obedece a juicios subjetivos y de interpretación de los expertos. Por tanto, el reto en este trabajo ha sido la introducción de operaciones lógicas que computen con palabras durante el análisis de los datos, para la elaboración de indicadores auto-interpretables de calidad del agua, que toleren la imprecisión e incertidumbre lingüística. Esta imprecisión típicamente refleja la ambigüedad del pensamiento humano para expresar percepciones. De allí que las variables lingüísticas se presenten como muy atractivas para el manejo de conceptos de la gestión medioambiental, como es el caso de la "calidad del agua", el "nivel de riesgo" o el "estado ecológico". Por tanto, en la presente Tesis, la flexibilidad de la lógica difusa para computar con palabras se ha adaptado a diversos tópicos en la gestión de la calidad del agua. Primero, se desarrolló un índice jerárquico multipropósito de calidad del agua que se obtuvo mediante razonamiento difuso. El índice integra un extenso grupo de indicadores que incluyen: contaminación orgánica, nutrientes, patógenos, variables macroscópicas, así como sustancias prioritarias micro-contaminantes. La importancia relativa de los indicadores al interior del sistema de inferencia se estimó con un método de análisis de decisiones, llamado proceso jerárquico analítico. En una segunda fase, se utilizó una metodología híbrida que combina los sistemas de inferencia difusos y las redes neuronales artificiales, conocida como neuro-fuzzy, para el estudio de la clasificación del estado ecológico de los ríos, de acuerdo con los lineamientos de la Directiva Marco de Aguas. Esta metodología permitió un manejo adecuado de la no-linealidad y naturaleza subjetiva de las variables involucradas en este problema clasificatorio. Con ella, se estudió la complejidad de los sistemas de inferencia, la selección apropiada de reglas lingüísticas y la influencia de las funciones que transforman las variables numéricas en lingüísticas. En una tercera fase, se desarrolló un modelo conceptual neuro-fuzzy concurrente basado en la metodología de evaluación de riesgo ecológico preliminar. Este modelo consideró la presencia de sustancias peligrosas en los ríos, e incorporó un mapa auto-organizativo para clasificar las sustancias químicas, en términos de su peligrosidad hacia los ecosistemas acuáticos. Con este modelo se estimaron potenciales de riesgo ecológico por combinación de factores de peligrosidad y de concentraciones de las sustancias químicas en el agua. Debido a la alta imprecisión e incertidumbre lingüística, estos potenciales se obtuvieron mediante sistemas de inferencia difusos, y se integraron por medio de distribuciones empíricas acumuladas, con las cuales se pueden analizar cambios espacio-temporales en la calidad del agua. Finalmente, se diseñó un sistema jerárquico de inferencia difuso para la evaluación del riesgo ecológico en sedimentos de ribera. Este sistema estima los grados de contaminación, toxicidad y riesgo en los sedimentos en términos lingüísticos, con sus respectivos niveles de certeza. El sistema se alimenta con información proveniente de análisis químicos, que detectan la presencia de sustancias micro-contaminantes, y de ensayos eco-toxicológicos tipo "screening" que usan la bacteria Vibrio fischeri. Como caso de estudio se seleccionó la cuenca del río Ebro, aunque las metodologías aquí desarrolladas pueden aplicarse fácilmente a otros ríos. En conclusión, este trabajo demuestra ampliamente que el diseño y aplicación de indicadores de calidad de las aguas, basados en la metodología de la lógica difusa, constituyen una herramienta sencilla y útil para los tomadores de decisiones encargados de la gestión sostenible de las cuencas hidrográficas.
262

Assessing Progress of Urban Ecological Restoration Using Transplants

Ihrig, Megan Esther January 2011 (has links)
Forests are the dominant terrestrial ecosystem in Ontario and were once widespread throughout much of eastern North America; in southern Ontario, forest cover has declined from 90% to approximately 17% in the past 200 years. Conversion of the surrounding landscape to urban and agricultural land uses creates edge effects which increase the impact of forest cover loss and threaten ecological integrity. Other impacts on forest ecological integrity include incompatible human activities, a generally inhospitable landscape matrix, and microenvironment changes, including those from chemical pollution and heat island effects. Coupled with direct degradation from human activities like free-riding, the altered forest microenvironment can facilitate increased invasion by opportunistic and competitive plant species, e.g. Alliaria petiolata (Brassicaceae). This tends to be worse in urban areas because of greater visitation that creates soil compaction, trampling, and more vectors to introduce the seeds of invasive species. Active management is often necessary in areas which have been degraded. Ecological restoration represents an important active management tool for urban forest protected area managers. The ecological restoration of the forest understory in altered and threatened habitats represents an important aspect of forest restoration. For this study, I tested the effectiveness of an ecological restoration using a multi-species assemblage approach with three native understory species to restore the herbaceous layer in Natchez Hills, an Environmentally Sensitive Policy Area in Kitchener, Ontario. The ecological restoration site was degraded and this reduced native plant species in the forest understory. The species selected, Caulophyllum giganteum (Farwell) Loconte & W.H. Blackwell (Berberidaceae), Podophyllum peltatum Linnaeus (Berberidaceae) and Maianthemum racemosum subsp. racemosum (Linneaus) Link (Asparagaceae), are widespread throughout eastern North America, and were selected for use in this study because of their persistence and relative abundance in Natchez Hills ESPA. Adult transplants were planted into 2 metre by 2 metre quadrats in different densities and shoot populations were monitored for two field seasons to determine if density played a role in early ecological restoration success. The methodology I designed for the ecological restoration was as practical as possible, given the real world financial and logistical constraints faced by many urban forest managers. Statistical analysis using repeated measures multivariate analysis of variance showed aerial shoot density did not have a significant effect on early restoration success rates (p > 0.05). However, there was a significant increase in restored species. Caulophyllum giganteum and Podophyllum peltatum shoot populations increased by over 97% at the ecological restoration site one year after transplanting. Maianthemum racemosum subsp. racemosum shoot populations increased by 51% at the site. For comparison, another study in the same forest reported early ecological restoration rates of 92% to 100% for herbaceous understory species, including C. giganteum and P. peltatum. Other North American studies using transplanted perennial herbaceous material reported average survival rates of 16.6% two years after planting (varying from 1.25% to 51.4% using eight herbaceous species in the Boston area), to 91% one year after restoration (varying from 42.1% to 100% using 19 herbaceous species of the deciduous forest in the Midwest). In instances where protected areas are degraded, active management and ecological restoration are often necessary tools. This ecological restoration demonstrated that the native herbaceous species used in this study are suitable for use in early ecological restorations in maple beech upland forests in the City of Kitchener. Using a practical and cost-effective methodology this ecological restoration experiment showed that it is possible to implement urban restoration of the forest understory in degraded areas, and to achieve success in early ecological restoration using native herbaceous forest understory species.
263

State-Society Relations and Ecological Environmental Governance in Mainland China: Taking the Huaihe River Valley as an Example

Yao, Hsiu-Yun 30 August 2012 (has links)
¡@Ecological and environmental problems of the 21st century are a serious threat to human survival and economic development. From open policy, Mainland China has made remarkable achievements in economic development, but also pays a heavy consideration for the resources and environment, unbalanced regional development and environmental diplomacy issues with neighboring countries. This paper tries to use literature, induction, case analysis of three research methods to analysis. This paper tries to find wrong creation of "because of" on Mainland China environmental problem. This paper comes by experience of developed countries to examine transformation of politics, economy, society policy in Mainland China, and tries in the economic development and pollution of the environment to achieve a balance. ¡@¡@Ecological environment has the properties of public goods and externalities. Central government is main actor of ecological environmental governance is no doubt. But state and society relations began to change with the transformation of the social and institutional change. Originally, Government monopoly to supply public goods began to shift to multiple actors supply model. This paper presents enterprises, Non-Governmental Organizations (NGOs), citizens of the three non-governmental actors and the relationship of the ecological environmental governance, and explores the interactive relationship between of central government and local government. On this basis, ecological environmental governance network theory as the core, proposed new ways to analysis the necessity and feasibility of ecological environmental governance network, and construct multiple actors of collaboration the new model of governance network. ¡@¡@The serious of environment problem in Mainland China faces severity influence economy growth, society security and people healthy. The environment depravation degree forces the environment non- government organization and citizen to joins. This paper used the case in the Huaihe River Valley. The environmental NGO, Huaihe River Guider, successes to connect with central government, citizen, and enterprise. Mainland China's central government still needs to strengthen rule of law construction and market mechanism establishment, particularly lawmaking guarantee the citizen participate, the solution mechanism of environment dispute, an arrange taking of dirty tax and fees etc., and then to expand this model to the pollution of various type in each city. Government absorbs the environmental governance experience, funds and technique of developed country by attending global governance, and then raises the environment quality of earth.
264

A study for PengHu of teacher in elementry school contribute ecological protection education

Hsu, Yu-Chen 26 July 2005 (has links)
In Penghu, there are natural areas of ecological protection which are spectacular in the domestic environment and rare in the world. And it is possible in the future for these areas to be developed into national geology parks or world heritage areas of ecology. Thus, the issue of establishing ecological protection areas in Penghu is quite often presented and quite appealing to the public. This research is being underway by inquires with the help of teachers in Penghu elementary schools, studying the value recognition, care attitude, willingness of participation, and levels of participation toward the issue of establishing Penghu¡¦s ecological protection areas. Next, this research is related to study the motives, methods, contents, and influences of teachers in Penghu elementary schools, who are assumed to carry out the task of ecological protection. At last, this research includes the effective methods of how to improve the teaching of ecological protection and presents the solutions of how to deal with the difficulties, which teachers in elementary schools have encountered. Through the computer¡¦s statistic analyses, the effective surveys can be generalized as the findings below: 1. The current major problems of ecological protection in Penghu are the unestablishment of ecological concepts and consensuses as well as the serious damages and changes of the wild inhabitants of animals and plants. Thus, how to place equal emphasis on the continuing development of economics and the island¡¦s ecological protection will become the future common direction of efforts for the various administrative agencies. 2. The attitudes and behaviors of the teachers in the county toward the public affairs are mostly conservative and passive when they are implementing the task of ecological protection. From the results of the surveys, most teachers agree that if schools can work with the organizations or groups of ecological protection, which will contribute to the teaching task of ecological protection. Thus, it seems necessary for schools and the educational agencies concerned to combine the work of ecological protection units and that of the teachers. 3. Most of the tasks of ecological protection by the teachers of this county are focused on meeting the needs of school curricula, which are influencing to the studying interests and concerns of students and to the interactions between students and teachers. Thus, it is obviously necessary for the agencies concerned to well arrange the related ecological curricula, such as the choices of teaching places, methods, strategies, contents, manpower resources, and the frequencies of teaching activities. 4. Most of the teachers agree that it is more effective for students to undertake ecological protection activities in the ecological protection areas than any other forms of teaching activities. Thus, it is worthwhile for the school authorities to deal with difficulties and to offer effective situations for teachers and students. 5. To the teaching of ecological protection, the major problem which most of the teachers have met with is the inadequacy of professional know-how in ecological protection. On the other hand, there are many teachers who have the same idea that teacher¡¦s professional expertise is the key to the success of undertaking ecological protection. Therefore, it is without doubt very important for the county¡¦s educational units to think of how to enhance teachers¡¦ reeducation, to cultivate their professional know-how about ecological protection, and to solve their teaching difficulties. 6. It is indeed a great help to the teachers¡¦ tasks on ecological protection that if schools can put emphasis on teachers¡¦ work, if communities can give them support, and if school administrative measures can be more enhanced. Thus, it is necessarily important for the school authorities to seek the communication and cooperation between the parents and the residents of the communities as well as to get more resources to help the teaching activities. 7. County administrative policies influence a lot on the undertaking effectiveness of ecological protection. Thus, it is an important objective for the county authorities in charge of ecological protection to meet with educational authorities to promote the county¡¦s ecological protection environment. At the same time, the various school units should establish a comprehensive teaching network on ecological protection in accordance with its own natural environment, human resources, and needs of curricula to compile the curricular materials of ecological protection.
265

A comparison of three rapid evaluation procedures for pine savanna wetlands

Henderson, Cynthia Joan. January 2001 (has links)
Thesis (M.S.)--Mississippi State University. Department of Agricultural and Biological Engineering. / Title from title screen. Includes bibliographical references.
266

Interregional ecology - resource flows and sustainability in a globalizing world

Kissinger, Meidad 11 1900 (has links)
In a globalizing world, trade has become essential to supporting the needs and wants of billions of people. Virtually everyone now consumes resource commodities and manufactured products traded all over the world; the ecological footprints of nations are now scattered across the globe. The spatial separation of material production (resource exploitation) from consumption eliminates negative feedbacks from supporting eco-systems. Most consumers remain unaware of the impacts that their trade dependence imposes on distant ecosystems (out of sight out of mind). I take the first steps in developing a conceptual and practical framework for an ‘interregional ecology’ approach to exploring and analyzing sustainability in an increasingly interconnected world. Such an approach accounts for some of the ‘externalities’ of globalization and international trade. It underscores the increasing dependence and impact of almost any country on resources originating from others and recognizes that the sustainability of any specified region may be increasingly linked to the ecological sustainability of distant supporting regions. I empirically describe and quantify some of the interregional material linkages between selected countries. I document the flows of renewable resources into the U.S. and quantify the U.S. external material footprint (EF) on specific countries. I then document the physical inputs involved in production of most agricultural export products from Costa Rica and Canada. Finally, I focus on major export products such as bananas, coffee and beef in Costa Rica and agricultural activities in the Canadian Prairies and document some of the ecological consequences (loss of habitat, soil degradation, water contamination and biodiversity loss) of that production. My research findings show increasing U.S. imports, increasing reliance on external sources and growing external ecological footprints. They also show how production activities mostly for overseas consumption led to changes in ecological structure and function in the studied export countries. This dissertation adds a missing trans-national dimension to the sustainability debate effectively integrating the policy and planning domain for sustainability in one region with that in others. While my research focuses mainly on documenting the nature and magnitude of interregional connections I also consider some of the implications of the interregional approach for sustainability planning.
267

Rethinking Economics: Accounting for Environmental Impact at a Local Level

Wilson, Jeffrey 11 April 2013 (has links)
The quality of the human experience depends on a dramatic change in how we think about economics and, more specifically, about the relationship between human economic activity and the natural world. The continued pursuit of a growth agenda threatens the health and stability of global ecological systems, jeopardizes the wellbeing of many people, and undermines opportunities for future generations. In an era of sustainability challenges, we must measure the impacts of economic activity and use that information toward designing more sustainable human systems. This dissertation supports an ecological economic worldview by extending biophysical based measures to local scale applications to improve understanding of environmental impact at the urban and sub-regional scale. To account for environmental impact, I test two calculation approaches: one to estimate municipal ecological footprint values and one to measure environmental impact at a neighbourhood level. The novel calculation approaches account for environmental impact at finer scales of resolution than has traditionally been applied. I also explore drivers of environmental impact using Halifax Regional Municipality as a case study. I examine the relationship between direct GHG emissions and socio-economic and wellbeing variables using a multivariate model. Those reporting to be married, young, low income, and living in households with more people have correspondingly lower direct GHG emissions than other categories in respective groupings. Respondents with lifestyles that generate higher GHG emissions did not report to be healthier, happier or more connected to their communities, suggesting that individuals can experience similar degrees of wellbeing largely independent of their GHG emissions. I explored whether where we live influences direct GHG emissions. Findings indicate that individuals living in the suburbs generate similar GHG emissions to those living in the inner city, challenging a widely held assumption that living in the inner city is better for sustainability. These results underscore the importance of understanding the spatial distribution of GHG emissions at the sub-regional scale. The research offers new insights to measure and understand environmental impact at the local level toward supporting ecologically informed decision-making.
268

Assessing Progress of Urban Ecological Restoration Using Transplants

Ihrig, Megan Esther January 2011 (has links)
Forests are the dominant terrestrial ecosystem in Ontario and were once widespread throughout much of eastern North America; in southern Ontario, forest cover has declined from 90% to approximately 17% in the past 200 years. Conversion of the surrounding landscape to urban and agricultural land uses creates edge effects which increase the impact of forest cover loss and threaten ecological integrity. Other impacts on forest ecological integrity include incompatible human activities, a generally inhospitable landscape matrix, and microenvironment changes, including those from chemical pollution and heat island effects. Coupled with direct degradation from human activities like free-riding, the altered forest microenvironment can facilitate increased invasion by opportunistic and competitive plant species, e.g. Alliaria petiolata (Brassicaceae). This tends to be worse in urban areas because of greater visitation that creates soil compaction, trampling, and more vectors to introduce the seeds of invasive species. Active management is often necessary in areas which have been degraded. Ecological restoration represents an important active management tool for urban forest protected area managers. The ecological restoration of the forest understory in altered and threatened habitats represents an important aspect of forest restoration. For this study, I tested the effectiveness of an ecological restoration using a multi-species assemblage approach with three native understory species to restore the herbaceous layer in Natchez Hills, an Environmentally Sensitive Policy Area in Kitchener, Ontario. The ecological restoration site was degraded and this reduced native plant species in the forest understory. The species selected, Caulophyllum giganteum (Farwell) Loconte & W.H. Blackwell (Berberidaceae), Podophyllum peltatum Linnaeus (Berberidaceae) and Maianthemum racemosum subsp. racemosum (Linneaus) Link (Asparagaceae), are widespread throughout eastern North America, and were selected for use in this study because of their persistence and relative abundance in Natchez Hills ESPA. Adult transplants were planted into 2 metre by 2 metre quadrats in different densities and shoot populations were monitored for two field seasons to determine if density played a role in early ecological restoration success. The methodology I designed for the ecological restoration was as practical as possible, given the real world financial and logistical constraints faced by many urban forest managers. Statistical analysis using repeated measures multivariate analysis of variance showed aerial shoot density did not have a significant effect on early restoration success rates (p > 0.05). However, there was a significant increase in restored species. Caulophyllum giganteum and Podophyllum peltatum shoot populations increased by over 97% at the ecological restoration site one year after transplanting. Maianthemum racemosum subsp. racemosum shoot populations increased by 51% at the site. For comparison, another study in the same forest reported early ecological restoration rates of 92% to 100% for herbaceous understory species, including C. giganteum and P. peltatum. Other North American studies using transplanted perennial herbaceous material reported average survival rates of 16.6% two years after planting (varying from 1.25% to 51.4% using eight herbaceous species in the Boston area), to 91% one year after restoration (varying from 42.1% to 100% using 19 herbaceous species of the deciduous forest in the Midwest). In instances where protected areas are degraded, active management and ecological restoration are often necessary tools. This ecological restoration demonstrated that the native herbaceous species used in this study are suitable for use in early ecological restorations in maple beech upland forests in the City of Kitchener. Using a practical and cost-effective methodology this ecological restoration experiment showed that it is possible to implement urban restoration of the forest understory in degraded areas, and to achieve success in early ecological restoration using native herbaceous forest understory species.
269

Interregional ecology - resource flows and sustainability in a globalizing world

Kissinger, Meidad 11 1900 (has links)
In a globalizing world, trade has become essential to supporting the needs and wants of billions of people. Virtually everyone now consumes resource commodities and manufactured products traded all over the world; the ecological footprints of nations are now scattered across the globe. The spatial separation of material production (resource exploitation) from consumption eliminates negative feedbacks from supporting eco-systems. Most consumers remain unaware of the impacts that their trade dependence imposes on distant ecosystems (out of sight out of mind). I take the first steps in developing a conceptual and practical framework for an ‘interregional ecology’ approach to exploring and analyzing sustainability in an increasingly interconnected world. Such an approach accounts for some of the ‘externalities’ of globalization and international trade. It underscores the increasing dependence and impact of almost any country on resources originating from others and recognizes that the sustainability of any specified region may be increasingly linked to the ecological sustainability of distant supporting regions. I empirically describe and quantify some of the interregional material linkages between selected countries. I document the flows of renewable resources into the U.S. and quantify the U.S. external material footprint (EF) on specific countries. I then document the physical inputs involved in production of most agricultural export products from Costa Rica and Canada. Finally, I focus on major export products such as bananas, coffee and beef in Costa Rica and agricultural activities in the Canadian Prairies and document some of the ecological consequences (loss of habitat, soil degradation, water contamination and biodiversity loss) of that production. My research findings show increasing U.S. imports, increasing reliance on external sources and growing external ecological footprints. They also show how production activities mostly for overseas consumption led to changes in ecological structure and function in the studied export countries. This dissertation adds a missing trans-national dimension to the sustainability debate effectively integrating the policy and planning domain for sustainability in one region with that in others. While my research focuses mainly on documenting the nature and magnitude of interregional connections I also consider some of the implications of the interregional approach for sustainability planning.
270

Post-hurricane growth and recruitment of plant species used by birds in northern Puerto Rico /

Sustache Sustache, José A. January 2004 (has links) (PDF)
Thesis (M.S.)--University of Puerto Rico, Mayagüez Campus, 2004. / Tables. Printout. Abstract in English and Spanish. Includes bibliographical references (leaves 30-38).

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