Refine
Document Type
- Doctoral thesis (15)
- Report (7)
- Book (4)
- Conference proceeding (4)
- Master thesis (2)
- Working paper (1)
Is part of the Bibliography
- no (33)
Year of publication
- 2019 (33) (remove)
Language
- English (33) (remove)
Keywords
- Kulturerbe (4)
- Optimierung (3)
- Umweltbezogenes Management (3)
- Baudenkmal (2)
- Conservation (2)
- Denkmalpflege (2)
- Elektrische Energie (2)
- Energiequalität (2)
- Energieressourcen (2)
- Energietechnik (2)
Institute
- FG Ingenieurmathematik und Numerik der Optimierung (7)
- FG Denkmalpflege (3)
- FG Allgemeine Technikwissenschaft (2)
- FG Biotechnologie der Wasseraufbereitung (2)
- FG Bodenschutz und Rekultivierung (2)
- FG Energieverteilung und Hochspannungstechnik (2)
- FG Umweltplanung (2)
- FG Verteilte Systeme und Betriebssysteme (2)
- FG Aerodynamik und Strömungslehre (1)
- FG Experimentalphysik und funktionale Materialien (1)
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.
In the time of increased awareness about the environment problems by the public opinion and also intensive international efforts to reduce emissions of greenhouse gases, as well increase of the generation of electrical energy to facilitate industrial growth, the conference offers broad contribution towards achieving the goals of diversification and sustainable development.
Focus of the student conference is to promote the discussion of views from scientists and students from Wroclaw University of Technology, Technical University of Ostrava and Brandenburg University of Technology Cottbus-Senftenberg.
The conference offers prominent academics and industrial practitioners from all over the world the forum for discussion about the future of electrical energy and environmental issues and presents a base for identifying directions for continuation of research.
We deal with a very complex and hard scheduling problem. Several types of products are processed by a heterogeneous resource set, where resources have different operating capabilities and setup times are considered. The processing of the products follows different workflows, allowing also assembly lines. The goal is to process all products in minimum time, i.e., the makespan is to be minimized. Because of the complexity of the problem an exact solver would require too much running time. We propose a compound method where a heuristic is combined with an exact solver. Our proposed heuristic is composed of several phases applying different smart strategies. In order to reduce the computational complexity of the exact approach, we exploit the makespan determined by the heuristic as an upper bound for the time horizon, which has a direct in uence on the instance size used in the exact approach. We demonstrate the efficiency of our combined method on multiple problem classes. With the help of the heuristic the exact solver is able to obtain an optimal solution in a much shorter amount of time.
We present a general numerical solution method for control problems with PDE-defined state variables over a finite set of binary or continuous control variables. We show empirically that a naive approach that applies a numerical discretization scheme to the PDEs (and if necessary a linearization scheme) to derive constraints for a mixed-integer linear program (MILP) leads to systems that are too large to be solved with state-of-the-art solvers for MILPs, especially if we desire an accurate approximation of the state variables. Our framework comprises two techniques to mitigate the rise of computation times with increasing discretization level parameters:
First, the linear system is solved for a basis of the control space in a preprocessing step. Second, certain constraints are just imposed on demand via the IBM ILOG CPLEX feature of a lazy constraint callback. These techniques are compared with an approach where the relations obtained by the discretization of the continuous constraints are directly included in the MILP. We demonstrate our approach on two examples: modeling of the spread of wildfire and the mitigation of water contamination. In both examples the computational results demonstrate that the solution time is significantly reduced by our methods. In particular, the dependence of the computation time on the size of the spatial discretization of the PDE is significantly reduced.
A tourism company that offers fly-in safaris is faced with the challenge to route and schedule its fleet of airplanes in an optimal way. Over the course of a given time horizon several groups of tourists have to be picked up at airports and flown to their destinations within a certain time-window. Furthermore the number of available seats, the consumption of fuel, the maximal takeoff weight, and restrictions on the detour of the individual groups have to be taken into account. The task of optimally scheduling the airplanes and tour groups belongs to the class of vehicle routing problems with pickup and delivery and time-windows. A flow-over-flow formulation on the time expanded graph of the airports was used in the literature in order to model this problem as a mixed integer linear program. Most of the benchmark problems however could not be solved within a time limit of three hours, which was overcome by formulating the problem for a simplified (time-free) graph and the use of an incumbent callback to check for feasibility in the original graph. While this approach led to very good results for instances, where few time-free solutions were infeasible for the original problem, some instances remained unsolved. In order to overcome this problem we derive two new exact formulations that include time as variables. Although these formulations by themselves are not better than the approach from the literature, they allow for an effective construction of graphs which can be interpreted as intermediate graphs between the graph of airports and the expanded graph with vertices for each visit. Using similar relaxation techniques to the time-free approach and constructing these graphs based on solutions of the relaxations guarantees that only critical airports are expanded. A computational study was performed in order to compare the new formulations to the methods from the literature. Within a time limit of 3 hours the new approach was able to find proven optimal solutions for all previously unsolved benchmark instances. Furthermore the average computation time of all benchmark instances was reduced by 90 percent.
Wetlands have gained tremendous importance since the 1970s, both in scientific discussion and in government policy discourse. The Ramsar Convention provided some clarity in definitions of wetlands and their natural and social significance. However, the current scientific understanding of wetlands was constructed in the centers of knowledge production in the West. One of the consequences has been that local knowledge of wetlands has been obscured or ignored altogether. This research uses methods of historical archaeology, ethnography, and archival work to explore the Anlo's local knowledge of wetlands in Ghana. Anlo local knowledge includes unique forms of wetland ownership arrangements, appropriate management approaches, and so-called atsidza are used as epistemic tools. Bryan Norton's conceptual framework of adaptive management gives an important role to local experimentation and is therefore seen as a key tool for sustainable management. Adaptive management is understood as anlo-style consensus-building management to appropriately incorporate local knowledge and western science into wetland management. The concept of adaptive management is modified accordingly to integrate postcolonial studies of knowledge production and thus can also contribute to the critical analysis of the integration of local knowledge, which has tended to be underestimated or even ignored in postcolonial theories.
Urban adaptation is a critical issue for many of the developing countries of Southeast Asia. Vietnam is likely to be among the countries most adversely affected by climate change. Moreover, its largest city, Ho Chi Minh City is considered worldwide as one of most vulnerable to a multitude of climate-related hazards, including flooding, sea-level rise and extreme heat events. Similar to other rapidly developing megacities in Southeast Asia, Ho Chi Minh City has undergone enormous changes in recent decades and has rapidly developed into an emerging megacity shaped by global processes and local settlement patterns. Recently, the need to adapt to the multiple stressors of rapid urbanisation and climate change has become increasingly evident. Adaptation to climate change in urban areas depends on decision-makers’ understanding of the current and future impacts of climate change. Land-use planning as a place-based and problem-solving strategy has been recognised as a key tool in this respect, to mainstream climate change adaptation and disaster risk reduction into urban development. Yet a key challenge is a lack of relevant information on exposed populations and assets at risk to planners and policymakers. The dissertation outlines the development of an integrated framework predominantly based on an urban structure type approach. This approach was used to manually interpret high resolution, remotely sensed imagery in order to portray and understand patterns of settlement and urban structure layout of the current and emerging landscapes of Ho Chi Minh City. The approach is able to capture the highly dynamic spatiotemporal, social and structural changes associated with rapid urbanisation. The overall findings show the applicability of the developed framework to produce important input indicators for risk adapted land-use planning. These are ultimately useful to determine hotspots for administrative interventions and to assist prioritising in spatial and urban planning decision-making.
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.
Scaling minimum features of ICs down to the 10nm- area and below has allowed high integration rates in electronics. Scaling at supply voltages of 1V and below also implies a rising level of stress which drives aging effects that reduce switching speed and the expected life time. Additionally, vulnerability from particle radiation is increased. Hence, fault detection and on-line correction become a must for many applications. However, not only fault tolerance but self-awareness becomes also an advantage. Provided that by being aware of its own healthy state allow optimized configurations regarding system operation modes and configurable hardware mechanism. This paper shows a preliminary work in a configurable circuit and explores its configuration possibilities when integrated into a complete system.
Conservation of heritage sites is an integral part of history and culture through which new generations can learn about their forefathers education, professionalism, cultural characteristics as well as their civilization. Almost all countries of the world tend to conserve their historical sites for their own generations and travellers from abroad. Despite Bangladeshs economy is becoming stronger, it is not paying enough attention to the development of archaeology to conserve its heritage sites. Unlike many other developing countries, Bangladesh tends to considers it a luxury to preserve it’s heritage sites. It is mainly because of the scarcity of land. The tiny country has a huge population (about 180 million), the density of which is perhaps the highest in the world.
Apart from some very significant heritage sites, most others are awfully neglected. Lack of education and awareness among the respective local people and other stakeholders are also responsible for most of the heritage sites facing threats of demolition, vandalism, losing authenticity and integrity.
Panamnagar, the case study for this thesis paper, is not apart from the above scenario. It is the last surviving intake city of lost Bengal. The place witnessed Mughal emperor, British rule, the partition of Bengal, Liberation war of Bangladesh, Hindu-Muslim riot, illegal habitation of people, forced eviction and abundance. The historic city went through lots of historical events and is still standing as a testimony to the golden era of Bengal. Currently, this heritage site is facing multiple threats to its existence and authenticity. The city is vacated by the authority - the Department of Archaeology. But as the local people are not aware of the historic value of the site, they are not at all cooperating with the authority. Meanwhile, the authority is trying to incorporate adaptive reuse of the site to give life to it again and collect revenue for the maintenance. But they are doing it without assessing the cultural significance of the site properly, which could be a potential threat for the authenticity of the heritage site. Thus, this paper has focused on assessing the cultural significance of the heritage site, with a hope that it will help the authority to make policy decisions for the conservation of the site more cautiously. To assess the cultural significance properly, history and architectural significance are described briefly. A site analysis has been conducted to understand the current site condition properly. The paper concludes with statements in support of the cultural significance of Panamnagar site and recommends appropriate conservation tools to sustain its significance.