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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.
51

Ökonomische und ökologische Bewertung der Auswirkungen des demografischen Wandels auf die Siedlungsentwässerung

Endrikat, Jan, Schlage, Franziska, Hillmann, Julia 28 December 2011 (has links) (PDF)
In recent publications it is questioned whether the existing wastewater management system is suitable for future requirements. The today’s wastewater infrastructure is a complex socio-technical system characterized by centralization, very long life-spans and sunk costs. Thus, it appears questionable whether this system is suitable against the background of a context of dynamic conditions as demographic change, climate change and the emerging requirements in terms of sustainability. This paper adds a contribution to the growing body of literature on prospective waste water management systems. Focusing on long term developments this paper aims to build up scenario-modules towards the year 2050. Our approach combines three methodologies which appear to be suitable with each other, namely the method of explorative scenario development, a modified Delphi method and content analysis. As the waste water sector is a very complex system with various impact factors which are characterized by high dynamics and strong uncertainty the scenario technique appears as an appropriate method. Within the scenario building process a modified Delphi method had been applied to generate the input for the scenario-modules. Key drivers and uncertainties in the field of waste water management were identified by interviewing 16 experts who are scientists or practitioners in the waste water sector. The interviews had been transliterated and then evaluated by using the content analysis approach. Afterwards scenario-modules were derived which provide a basis for further procedure towards complete scenarios for future wastewater infrastructure.
52

Bewertung von Szenarien für Energiesysteme: Potenziale, Grenzen und Akzeptanz

Schubert, Daniel Kurt Josef 24 May 2016 (has links) (PDF)
Die Dissertationsschrift führt im Gegensatz zu bisherigen Ansätzen im Zusammenhang mit der Energiewende einen Perspektivwechsel hin zur gesellschaftlichen Berücksichtigung herbei. Bisherige Szenariostudien richteten ihren Fokus auf die technische Machbarkeit sowie einzelne Kosten- und Umweltaspekte, wie in der Voranalyse gezeigt wird. Die Gesellschaft spielt in diesem Fall eine sekundäre Rolle. Statt einer Berücksichtigung im vorab geschalteten Entscheidungsprozess werden so häufig erst im Anschluss Zeit und Aufwand in die nachgelagerte Überzeugung der Bevölkerung investiert. Der in der Arbeit verfolgte Ansatz setzt konsequent darauf, gesellschaftliche Präferenzen und Barrieren vorab in die Entscheidungsfindung einzubeziehen, damit Entscheidungen selbst nachhaltig Bestand haben. Dazu werden repräsentative Telefonbefragungen genutzt, mit denen einerseits die Präferenzen der Bevölkerung, andererseits die Grenzen der Akzeptanz in Form der Zahlungsbereitschaft ermittelt werden. Erst im Anschluss daran werden Szenariorechnungen durchgeführt, um energiepolitische Handlungsoptionen auch quantitativ bewerten zu können. Bei der anschließenden Gegenüberstellung von gesellschaftlichen Barrieren und Modellergebnissen werden jedoch auch die Grenzen dieses Ansatzes vor Augen geführt: So kann eine aus Bevölkerungsperspektive erwünschte Handlungsoption (hier der Braunkohleausstieg) auch an politischen und rechtlichen Schranken scheitern.
53

The role of biobased building materials in the climate impacts of construction : Effects of increased use of biobased materials in the Swedish building sector

Peñaloza, Diego January 2017 (has links)
A significant share of the global climate change impacts can be attributed to the construction sector. One mitigation strategy is increasing the use of biobased materials. Life cycle assessment (LCA) has been used to demonstrate the benefits of this, but forest complexities create uncertainty due to omission of key aspects. The aim of this thesis is to enhance understanding of the effects of increasing use of biobased materials in climate change mitigation of construction works with a life cycle perspective. Non-traditional LCA methodology aspects were identified and the climate impact effects of increasing the use of biobased materials while accounting for these was studied. The method applied was dynamic LCA combined with forest carbon data under multi-approach scenarios. Diverse case studies (a building, a small road bridge and the Swedish building stock) were used. Most scenarios result in impact reductions from increasing the use of biobased materials in construction. The inclusion of non-traditional aspects affected the results, but not this outcome. Results show that the climate mitigation potential is maximized by simultaneously implementing other strategies (such as increased use of low-impact concrete). Biobased building materials should not be generalised as climate neutral because it depends on case-sensitive factors. Some of these factors depend on the modelling of the forest system (timing of tree growth, spatial level approach, forest land use baseline) or LCA modelling parameters (choice of the time horizon, end-of-life assumptions, service life). To decrease uncertainty, it is recommended to use at least one metric that allows assessment of emissions based on their timing and to use long-term time horizons. Practitioners should clearly state if and how non-traditional aspects are handled, and study several methodological settings. Technological changes should be accounted for when studying long-term climate impacts of building stocks. / Irreversibel global påverkan på klimat och miljö måste undvikas och olika strategier som begränsar klimatförändringarna kan utnyttjas för att hantera denna utmaning. En betydande andel av de globala utsläppen av växthusgaser kan hänföras till byggsektorn i allmänhet och cementproduktion i synnerhet, och begränsningsstrategier söker alternativ till fossil- och mineralbaserade resurser, med mindre påverkan, som exempelvis en ökad användning av biobaserade material i byggandet. Livscykelanalys (LCA) har använts för att demonstrera klimatnyttan av denna ökning, men skogens komplexiteter i samband med biogent koldioxid skapar osäkerhet i resultaten då de som genomför LCA-studier traditionellt utelämnar viktiga nyckelaspekter. Denna avhandling syftar till att öka förståelsen för effekterna av en ökad användning av biobaserade material för begränsning av byggandets klimatpåverkan i ett livscykelperspektiv. Forskningsfrågorna formulerades med fokus på att identifiera icke-traditionell LCA-metodik, samt att bedöma miljöeffekterna av en ökad användning av biobaserade material med redovisning av dessa aspekter på olika nivåer, gällande enstaka konstruktioner och byggnadsbeståndet som helhet. Den metodik som används är dynamisk LCA i kombination med data om skogskolbalans, med analyser av flera scenarier med olika metodologiska antaganden. Fallstudier med olika kännetecken användes, nämligen en byggnad, en bilvägsbro och en uppskattning av det svenska byggnadsbeståndet på lång sikt. Resultaten bekräftar att en ökad användning av biobaserade material minskar klimatpåverkan av byggandet – en tydlig majoritet av de scenarier som analyserats för alla fallstudier resulterar i sänkt klimatpåverkan. Införandet av icke-traditionella LCA-aspekter påverkar resultatet, men förändrar inte att en ökad användning av biobaserade material resulterar i lägre långsiktig och kumulativ klimatpåverkan. Resultaten visar också att den maximala klimatbegränsningspotentialen endast nås genom att samtidigt införa andra tekniska lösningar med lägre klimatpåverkan. När det gäller LCA-metodik visar resultaten att antagandet att biobaserade byggnadsmaterial är klimatneutrala är en överförenkling eftersom deras klimatpåverkan beror på fallspecifika faktorer och därför bör inga generaliseringar göras. Några av dessa klimatpåverkande faktorer beror på modellering av skogssystemet i en dynamisk LCA; såsom när skogstillväxten antas börja i förhållande till avverkningen, den geografiska upplösningen för att analysera de biogena kolflödena dvs. som ett avverkningsbestånd eller på landskapsnivå och vad utgångsläget sätts till vid analys av skogens markanvändning. Andra faktorer beror på LCA-modellering, nämligen valet av integrerad tidshorisont för beräkning av klimatpåverkan, det antagna scenariot för avfallshantering och lagringsperioden för det biogena kolet i tillverkade produkter. För att minska osäkerheten i bedömning av klimatpåverkan av biobaserade byggmaterial rekommenderas användning av minst en mätmetod som gör det möjligt att bedöma koldioxidutsläppen baserat på tidpunkten på dessa, samt att tillämpa mätvärden med långa tidsperspektiv. Redovisning av icke-traditionella aspekter har en betydande effekt på klimatpåverkan av biobaserade byggmaterial. Utförare av analyser rekommenderas därför även att redovisa hur dessa aspekter hanteras och att ställa upp flera olika scenarier och analysera dessa med flera olika metodologiska inställningar. Slutligen rekommenderas att ta hänsyn till den tekniska utvecklingen vid analyser av långsiktig klimatpåverkan av byggnadsbeståndet som genomförs med dynamiska värden för processer som äger rum i framtiden. / Para evitar impactos irreversibles a nivel global, es necesario mitigar el cambio climático. Una parte significativa de las emisiones globales de gases efecto invernadero puede atribuirse al sector de la construcción y la producción de cemento. Entretanto, se busca implementar estrategias de mitigación de bajo impacto, tal es el caso de incrementar el uso de materiales de origen forestal. El análisis de ciclo de vida (ACV) se aplica con frecuencia para demostrar los beneficios climáticos de este incremento, pero las complejidades relacionadas con el bosque y el carbono biogénico crean incertidumbre ya que los autores normalmente omiten ciertos aspectos clave. Esta tesis busca mejorar la comprensión de los efectos de un incremento en el uso de materiales de origen forestal en la mitigación del cambio climático en el sector de la construcción, bajo una perspectiva de ciclo de vida. Para ello se han formulado preguntas de investigación centradas en la identificación de los aspectos metodológicos no tradicionales del ACV que pueden afectar el resultado, así como en la evaluación de los efectos ambientales del aumento del uso de materiales biológicos en construcciones o en la construcción en existencia, mientras se toman en cuenta dichos aspectos. Los métodos aplicados incluyen el ACV dinámico en combinación con modelos del balance de carbón en el bosque, además del análisis de múltiples escenarios con diferentes configuraciones metodológicas y asunciones. Se utilizaron casos de estudio con diferentes características y sus respectivos productos equivalentes de referencia; un edificio, un puente para carretera pequeño y la construcción en existencia en Suecia a largo plazo. Los resultados confirman que el aumento del uso de materiales de origen forestal disminuye el impacto climático de la construcción, ya que la gran mayoría de los escenarios analizados para todos los casos de estudio resultan en reducciones del impacto climático. La inclusión de aspectos no tradicionales del ACV ha influido en los resultados, sin afectar el hecho de que incrementar el uso de material biológico se traduce en menores impactos climáticos acumulados a largo plazo. Los resultados también muestran que el potencial máximo de mitigación climática sólo se alcanza mediante la implementación simultánea de otras tecnologías de bajo impacto. En cuanto a la metodología del ACV, la tesis ilustra que la hipótesis de que los biomateriales de construcción son neutrales respecto a sus impactos climáticos es una simplificación excesiva, y demuestra también que los flujos de carbono biogénico deben ser tenidos en cuenta. El balance de carbono de los materiales de construcción de origen forestal depende de factores relacionados con el sistema forestal que son sensibles las circunstancias del caso de estudio; por lo que no deberían hacerse generalizaciones. De dichos factores, algunos dependen de los modelos usados para simular el sistema forestal; tales como la contabilización del punto temporal de ocurrencia de los flujos de carbono biogénico, la perspectiva espacial para medir estos flujos y la línea de base trazada para el sistema forestal. Otros factores dependen del modelo usado para el ACV, como la elección del horizonte temporal integrado para el cálculo del impacto, el escenario de disposición final y el período de almacenamiento del carbono biogénico en los productos. Para obtener conclusiones más robustas, se recomienda que los autores de estudios utilicen al menos un método adicional al GWP que les permita evaluar las emisiones de carbono basadas en el punto temporal de su ocurrencia, así como que se apliquen horizontes temporales a largo plazo en el uso de dichos métodos. Tener en cuenta los aspectos no tradicionales estudiados en esta tesis en estudios de ACV de materiales de construcción de origen forestal puede tener una influencia significativa en su impacto climático, por lo que se recomienda que los autores expongan claramente si estos aspectos se incluyen y cómo se incluyen. También se recomienda que se analicen múltiples escenarios con una variedad de configuraciones metodológicas alternativas. Por último, se recomienda tener en cuenta los cambios tecnológicos en los análisis a largo plazo de los impactos climáticos de la construcción en existencia, utilizando factores de impacto dinámico para los procesos que trascurran en el futuro. / <p>QC 20170517</p> / EnWoBio - Engineered Wood and Biobased Building Materials Laboratory
54

A Hybrid of Stochastic Programming Approaches with Economic and Operational Risk Management for Petroleum Refinery Planning under Uncertainty

Khor, Cheng Seong January 2006 (has links)
In view of the current situation of fluctuating high crude oil prices, it is now more important than ever for petroleum refineries to operate at an optimal level in the present dynamic global economy. Acknowledging the shortcomings of deterministic models, this work proposes a hybrid of stochastic programming formulations for an optimal midterm refinery planning that addresses three factors of uncertainties, namely price of crude oil and saleable products, product demand, and production yields. An explicit stochastic programming technique is utilized by employing compensating slack variables to account for violations of constraints in order to increase model tractability. Four approaches are considered to ensure both solution and model robustness: (1) the Markowitz’s mean–variance (MV) model to handle randomness in the objective coefficients of prices by minimizing variance of the expected value of the random coefficients; (2) the two-stage stochastic programming with fixed recourse approach via scenario analysis to model randomness in the right-hand side and left-hand side coefficients by minimizing the expected recourse penalty costs due to constraints’ violations; (3) incorporation of the MV model within the framework developed in Approach 2 to minimize both the expectation and variance of the recourse costs; and (4) reformulation of the model in Approach 3 by adopting mean-absolute deviation (MAD) as the risk metric imposed by the recourse costs for a novel application to the petroleum refining industry. A representative numerical example is illustrated with the resulting outcome of higher net profits and increased robustness in solutions proposed by the stochastic models.
55

Sozioökonomische Entscheidungskriterien zu Kurzumtriebsplantagen in Bioenergiedörfern aus kommunaler und nationaler Perspektive

Neubert, Florian P. 04 June 2018 (has links) (PDF)
Das Ziel der vorliegenden Monografie besteht in der Identifikation sozioökonomischer Entscheidungskriterien und Rahmenbedingungen zum Anbau von Kurzumtriebsplantagen in Bioenergiedörfern aus kommunaler und nationaler Perspektive und in der Bewertung zukünftiger Potenziale in Deutschland.
56

Rural Electrification and Societal Impacts on Future Energy Demand in Bolivia: A Case Study in an Altiplano Community

Ålund, Anton January 2017 (has links)
Social variables are a predominant force to community development in rural areas. However, research on how social aspects affect the energy situation as a community expands is to date limited. This study aims explore this void and investigate the following question: “What could be a feasible pathway to reach a sustainable and resilient future state in Micaya, based on the impact of key variables within three different sectors: education, health and production?” In this study, theories and models of rural electrification and scenario analysis are transposed and applied to community operated rural electrification in order to frame development. The investigation is restricted to focus on three social sectors, healthcare, education and production. Current literature confirmed that social aspects are missing in rural electrification programs.  Through interview and discussion with an established expert group important social variables have been identified in the study community. These variables lay the foundation for the scenario building used to define a desirable future in the case study community. It was found that the variables within the production sector are most influential to future developments in the study community.  The study revealed that energy access, especially access to electricity, is an essential condition for the development of rural communities. However, it does not guarantee an increase in productivity or effectiveness in social institutions in the absence of other development programs. The study also concludes that well-planned, carefully implemented rural electrification programs provide enormous benefits to rural people. Once an area has reached a certain level of development, further improvement of societal institutions depends on the availability of a secure and stable energy supply.
57

Should Sweden impose excise tax on sugar-sweetened beverages in order to improve public health?

Edfeldt, Johan, Petersson Edfeldt, Linn January 2017 (has links)
In recent time, several reports have been published about a more and more unhealthy population world wide, with increasing Body Mass Index (BMI) in welfare countries, such as Sweden. Diseases, such as obesity and diabetes, which is strongly connected to a high BMI, have increased and together with them also the medical expenses for society/state. Several initiatives have been started, in different countries, to tackle these problems and some have introduced a “sugar tax” on unhealthy products, like candy and soda, which has become a well- debated subject also in Sweden today. In this MBA master thesis, a literature study has been conducted with the goal of evaluating if an excise tax should be introduced in an efficient way on unhealthy sugar-sweetened beverages in Sweden. This case study is built on secondary data where reports and official statistics, from governments and health authorities/organizations, have been studied both for Sweden as well as from other countries. There has been a particular focus on Sweden's neighbouring countries Denmark and Finland, who has both experiences in the implementation of a “sugar tax”. Our theory is that introducing an excise tax on sugar-sweetened beverages will reduce the demand and consumption of these products, which will reduce welfare disease such as obesity and diabetes and yield a tax income for the state. However it is important to have in mind that the reduced consumption also will result in less tax income from the no longer sold goods, fewer personnel employed in the producing industries etc. The results showed that the overall sugar consumption actually has decreased in Sweden, as well as the overall consumption of sugar-sweetened beverages. However during the same time period the average calorie consumption and BMI has continued to increase resulting in a more unhealthy population that results in increased medical expenses. In conclusion an excise tax on sugar-sweetened beverages will not solve the welfare disease problems but may positively influence health. However it comes with a price also for the state from both gains and loss in tax incomes and increased administrations costs for managing the new tax. Finally it should be noted that since sugar-sweetened beverages are unhealthy products, which do not contribute to any positive health effects, sugar taxation might still be considered.
58

Model dynamiky lidských zdrojů v projektovém řízení / Dynamic model of human resources in project management

Hančar, Michal January 2016 (has links)
This thesis is focused on dynamics of soft factors influencing workers during projects. These factors include motivation, workplace atmosphere, team synergy of workers and their emotions, and attribute of project manager who manages the project. Identification of soft factors and their relationships was achieved by examination of scientific literature in psychology and system dynamics. Description of managing project matters was achieved by examination of scientific literature dealing with project management. The main objective of this thesis is to create a dynamic model which simulates behavior of these soft factors influencing the project staff. The primary metric of the model is efficiency of workers participating on the project based on input parameters. Validation of the model was achieved by verification of historic behavior of key elements. Results of validation experiments correspond with historic behavior with roughly 95 % accuracy. At the end of this thesis is presented an ICT project case study. Based on the results of simulation experiments is performed a scenario analysis which tries to bring possible suggestions for project management.
59

Sozioökonomische Entscheidungskriterien zu Kurzumtriebsplantagen in Bioenergiedörfern aus kommunaler und nationaler Perspektive

Neubert, Florian P. 18 December 2017 (has links)
Das Ziel der vorliegenden Monografie besteht in der Identifikation sozioökonomischer Entscheidungskriterien und Rahmenbedingungen zum Anbau von Kurzumtriebsplantagen in Bioenergiedörfern aus kommunaler und nationaler Perspektive und in der Bewertung zukünftiger Potenziale in Deutschland.
60

Betriebswirtschaftliche Szenarien auf regionaler Ebene im Hinblick auf die Einflüsse des Klimawandels

Lehmann, Katrin 30 April 2010 (has links)
Klimawissenschaftler sind sich heute weitgehend einig, dass aktuell ein durch den Menschen verursachter Wandel des Klimas stattfindet, welcher große Auswirkungen auf die Menschheit im Allgemeinen hat, aber auch auf die Unternehmenspraxis. Anpassungsmaßnahmen an diese Auswirkungen stellen eine wichtige Möglichkeit dar, die wirtschaftlichen Schäden durch den Klimawandel zu begrenzen bzw. zu vermeiden. Im Rahmen des Projektes REGKLAM („Entwicklung und Erprobung eines integrierten Regionalen Klimaanpassungsprogramms für die Modellregion Dresden“) wird der Einfluss des Klimawandels auf Unternehmen der Region Dresden untersucht, um solche geeigneten Anpassungsmaßnahmen zu entwickeln. Die Methode der Szenarioanalyse wird dabei genutzt, um den Klimaeinfluss auf betriebswirtschaftliche Größen, vorrangig in der regionalen Tourismusbranche, zu analysieren. Dazu wird zunächst eine umfassende Literaturrecherche durchgeführt, deren Ergebnis den Rahmen für eine Szenarioanalyse für die Branche Tourismus der Region Dresden liefert. Im Ergebnis werden einige Anpassungsstrategien für diese Branche erarbeitet.

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