@phdthesis{An2015, author = {An, Ni}, title = {Statistical analysis of extreme climate events in Brandenburg}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-36117}, school = {BTU Cottbus - Senftenberg}, year = {2015}, abstract = {The main idea of this paper is to evaluate the performance of the fine resolution CLM model in the state of Brandenburg Germany, create a bias correction method and reanalyze the climate signals of the corrected simulations on projections of the 21st century. The bias correction method is a distribution oriented method and the analysis is mainly focused on the extreme events such as 95 and 5 percentile daily temperatures and 95 percentile daily precipitations in a period of 30 years, but also includes seasonal temperature, daily temperature difference and monthly precipitation to demonstrate the effectiveness of the correction method. The results showed that the correction method was very effective on different variables. After correction, the extreme daily temperature bias was reduced from a cold bias of 1-2K to less than 0.1K. The corrected projection simulations suggested that the extreme temperatures were about to increase both in intensity and in frequency. The extreme precipitation after correction was meant to become more severe and frequent as well.}, subject = {Bias correction; Climate simulation; CLM model evaluation; Climate signal analysis; Bias Korrektur; Klima Simulation; CLM Modell Auswertung; Klima Signal Analyse; Brandenburg; Klima; Modell; Statistische Analyse; Simulation}, language = {en} } @phdthesis{Andolfo2017, author = {Andolfo, Franco}, title = {Energieeffizientes N{\"a}hrstoffsplitting von fl{\"u}ssigen Wirtschaftsd{\"u}ngern mittels Membranfiltration}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-42805}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {Die definierte Selektivit{\"a}t der Membranfiltration kann dazu genutzt werden, einzelne spezifische G{\"u}lle-Separationsprobleme in {\"u}bergeordneten Aufbereitungsklassen zusammenzufassen. Mit dem Ansatz einer gesteuerten N{\"a}hrstofftrennung bzw. Teilzusammenf{\"u}hrung von modifizierten Str{\"o}men, und der Zuordnung von spezifischen Aufgaben an die Mischprodukte, werden die Nachteile des Ausgangsrohstoffs reduziert und der Wertstoff G{\"u}lle r{\"u}ckstandsfrei nutzbar gemacht. Mit einem Anlagenmodell, bestehend aus einer Hydrotankpresse als Vorfiltration und einer Ultrafiltration als Kernkomponenten, ist es {\"u}ber empirisch ermittelte Betriebsparameter m{\"o}glich, einen energetisch optimierten und kontinuierlichen Produktionsbetrieb durchzuf{\"u}hren. Als Produkte der dezentralen Aufbereitungsanlage werden ein emissionsreduzierender Fl{\"u}ssigd{\"u}nger, eine als Brennstoff und als G{\"a}rsubstrat geeignete Feststoffphase, sowie das Retentat als aktivierendes Material zur Biogasertragssteigerung gewonnen. Das untersuchte Anlagenmodell ist auf den innerbetrieblichen Einsatz in Milchviehhaltungsbetrieben abgestimmt. Mit der Erarbeitung von stabilen und energetisch g{\"u}nstigen Anlagenbetriebspunkten wird das Anlagenverhalten hydraulisch steuerbar. Durch die Zuordnung von Anlagenzust{\"a}nden zu differenziertem Sp{\"u}lverhalten, wird die direkte Einflussnahme der Temperatur auf den Permeat-Flux erkennbar. Der Einsatz eines Tauchk{\"u}hlers, mit voreingestellten Grenztemperaturen, stabilisiert signifikant das Anlagenverhalten im Vergleich zu konventionellen Anlagenkonfigurationen. Die Anwendung einer Hydropresse gestattet h{\"o}here TDS-Belastungen im UF-Kreislauf, bietet aber kein Potenzial zur Steigerung der N{\"a}hrstoffdurchs{\"a}tze. Dies gilt auch f{\"u}r den Einsatz einer 300 kDa-Variante, im Vergleich zur priorisierten 150 kDa-UF-Membran. Mit der Hydropresse kann eine h{\"o}here Feststoffabscheidung wie mit Verstopfungs- bzw. Siebfiltrationen erreicht werden, die TDS-Belastungen sind im Retentat auf 5.000 - 7.000 ppm limitiert, oder m{\"u}ssen durch Verd{\"u}nnung auf diese Werte eingegrenzt werden. Mit der zus{\"a}tzlichen Anwendung einer Gassp{\"u}lung in der Anstr{\"o}mung der UF-Module, k{\"o}nnen TDS-Belastungen {\"u}ber 10.000 ppm erstmals dauerhaft bew{\"a}ltigt werden. {\"U}ber die so erweiterte Verfahrenstechnik sind Standzeiten von mehreren Wochen, ohne betrieblich bedingte Unterbrechungen, m{\"o}glich. Die durch Fluoreszenzmikroskopie nachweisbare Anreicherung von Methanbildnern im Retentat, best{\"a}tigt eine m{\"o}gliche Anwendung des Retentats als Biogassubstraterg{\"a}nzung. Der Biogasertrag wird durch Zusatz von Retentat zu den bisher verf{\"u}gbaren Substraten generell erh{\"o}ht. Eine Mischung aus Retentat und dem Feststoff aus der Hydropresse unterst{\"u}tzen die biochemische Stabilisierung in Fermentern. In Kombination mit Anteilen an Feststoff ist das Permeat bei der Bewertung von pflanzenbaulichen Ertr{\"a}gen, als konkurrenzf{\"a}hig zu Rohg{\"u}lle und Mineralstoffd{\"u}nger einzustufen. Das auf landwirtschaftliche Fl{\"a}chen ausgebrachte Permeat ist geruchslos.}, subject = {N{\"a}hrstoffsplitting; Nutrient splitting; Membranfiltration; Membrane filtration; Wirtschaftsd{\"u}nger; Farm fertilizer; Klimaschutz; Climate protection; Umweltschutz; Environment protection; Membranfilter; Wirtschaftsd{\"u}nger; Technikumsanlage; Klimaschutz}, language = {de} } @phdthesis{Andreessen2023, author = {Andreeßen, Lena M.}, title = {Towards real-world applicability of neuroadaptive technologies : investigating subject-independence, task-independence and versatility of passive brain-computer interfaces}, doi = {10.26127/BTUOpen-6652}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-66521}, school = {BTU Cottbus - Senftenberg}, year = {2023}, abstract = {Brain-computer interfacing (BCI) is a relatively new field of study that involves engineering, neuroscience, psychology, and physiology. A BCI is a system that allows direct communication between the brain and the environment, using signals from electroencephalography (EEG) to identify a user's intentions and mental states. This can be used for human-machine interaction (HMI) to adapt software or control a device. Particularly passive BCIs are the most promising for the general population, as they can detect and interpret a user's mental state without requiring their attention. This can enable neuroadaptive technology (NAT), which allows a machine to learn over time how the user perceives and interprets the world. However, there are still obstacles to be overcome before BCI technology can be applied in real-world situations for NAT. In this work I firstly address the issue of subject dependence in training data collection for classifier calibration, which can be time-consuming and impractical. I investigated the training of a subject-independent predictive model that is trained on a group of other users' data and applied to online-testing data of a new person. This was done in the context of training an automatic classifier for error detection and correction. Results showed that a classifier model can be trained without user-specific calibration and with high accuracy. The number of electrodes used in training the model was also reduced. Further it was validated that the trained classifier models were based on cortical sources and not other modalities. In a second study I address the issue of task-dependence. To that end I tested the application of a potentially task-independent calibration paradigm for mental workload assessment in a new task. This new task was a speed reading context, where subjects read texts of varying difficulty and speed. The study found that the mental workload prediction model was accurate in classifying mental workload in different reading tasks, indicating that it can be used as a task-independent classifier for mental workload. In a third study I examine if it is possible to measure neural correlates of human moral assessment using a passive BCI on a single-trial basis. A calibration paradigm was developed using pictures that were ranked as morally unacceptable and morally neutral. However, the results showed low classification accuracies and it was not possible to reliably distinguish between a user's subjective moral evaluations on a single-trial basis using current classification approaches. The results presented in this thesis provide solutions towards real-world applicability of NAT enabled by passive BCIs, as examples of a subject-independent and a task-independent classifier are demonstrated and discussed. Further, approaches for increased versatility of passive BCI technology are presented, that could make passive BCIs more feasible for use in future real-world human-machine interaction settings.}, subject = {Passive brain-computer interfaces; Mental state assessment; Neuroadaptive technology; Human-machine interaction; Electroencephalography; Passive Gehirn-Computer-Schnittstellen; Neuroadaptive Technologie; Mensch-Maschine-Interaktion; Elektroenzephalographie; Erfassung mentaler Zust{\"a}nde; Elektroencephalographie; Hirnfunktion; Mensch-Maschine-Interaktion; Gehirn-Computer-Schnittstelle}, language = {en} } @phdthesis{Andrei2018, author = {Andrei, Andreea Cristina}, title = {Untersuchung und Optimierung robuster und hochlinearer rauscharmer Verst{\"a}rker in GaN-Technologie}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-44782}, school = {BTU Cottbus - Senftenberg}, year = {2018}, abstract = {Die n{\"a}chste Generation von integrierten Sende- und Empfangsystemen erfordert sowohl robuste rauscharme Verst{\"a}rker als auch Leistungsverst{\"a}rker auf einem einzelnen Chip. Die GaN-HEMT-Technologie hat bisher gezeigt, dass sie durch ihre hohen Durchbruchspannungen, die hohe Elektronenbeweglichkeit und die niedrige Rauschzahl ein guter Kandidat f{\"u}r die Realisierung solcher Systeme ist. Diese Arbeit besch{\"a}ftigt sich mit hochlinearen und robusten rauscharmen Verst{\"a}rkern, welche in Sender-Empf{\"a}nger-Systeme integriert werden k{\"o}nnen. Zuerst wird der GaN HEMT charakterisiert. Die Eigenschaften von Transistoren werden w{\"a}hrend des Burn-in Prozesses und gepulster Anregung mit hoher {\"U}berlast am Eingang analysiert. Damit werden die Grundlagen f{\"u}r das Verst{\"a}ndnis des Verhaltens eines Verst{\"a}rkers w{\"a}hrend und nach der {\"U}bersteuerung am Eingang gelegt. Der Hauptteil dieser Arbeit zeigt die Entwicklung und die Charakterisierung von robusten rauscharmen Verst{\"a}rkern. Dar{\"u}ber hinaus wird ein neues Konzept f{\"u}r die Steigerung der Robustheit entwickelt, gemessen und charakterisiert. Das Konzept verwendet eine neuartige Zusammenschaltung zweier Transistoren am Verst{\"a}rkereingang, wodurch die Spannungsfestigkeit gegen{\"u}ber hohen Leistungspegeln gesteigert wird. Damit konnten H{\"o}chstwerte von +44dBm mit CW-Anregung und +47dBm mit gepulster Anregung am Verst{\"a}rkereingang ohne Besch{\"a}digung demonstriert werden.}, subject = {GaN HEMT; Rauscharme Verst{\"a}rker; Robustheit; Stacked Verst{\"a}rker; {\"U}bersteuerung mit hoher Eingangsleistung; GaN HEMT; Low noise amplifier; Ruggedness; Stacked amplifier; Input power overdrive; Rauscharmer Verst{\"a}rker; Galliumnitrid; HEMT; Robuste Regelung}, language = {de} } @phdthesis{AndredaRocha2012, author = {Andr{\´e} da Rocha, Andreza}, title = {The Birth of Brazilianism : the stereotypical representation of Brazil in the context of cultural imperialism and media concentration}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-27288}, school = {BTU Cottbus - Senftenberg}, year = {2012}, abstract = {The representation of Brazil in American mainstream cinema disseminates stereotypes that have their roots in narratives produced by European explorers during the colonial era. Films and other media from Brazil portray the country's cultural and ethnic diversity more accurately, but due to media concentration and the global supremacy of the US-based film and television industry, only a few manage to reach international audiences and challenge widespread stereotypes. A critical examination of writings of Portuguese explorers produced in the centuries following the arrival of Pedro {\´A}lvares Cabral in Brazil provides the basis for the analysis of contemporary representations of Brazil in American cinema and reveals how early descriptions of Brazil have influenced these representations. In order to identify the main Brazilian stereotypes disseminated by feature films produced in the United States, a number of films released between 1984 and 2011 are analyzed. The results of the analysis allow for the identification of an ethnocentric regime of representation that is often employed by the world's leading film and television industry to portray Otherness, reinforcing stereotypical ideas about racial difference and the culture and people of developing countries. The analysis is followed by a discussion of cultural imperialism, media concentration and its impact on cultural diversity and media pluralism. The investigation of the concentrated ownership of media, which raises concerns regarding cultural homogenization, the advancement of corporate interests over the public interest and loss of cultural diversity, indicates how media concentration contributes to the perpetuation of cultural, ethnic and national stereotypes that reinforce colonialist and reductionist ideas about developing countries. The results of the film analysis, combined with issues related to the increasing concentration of media ownership, confirm the proposition to revive the debate about a New World Information and Communication Order (NWICO), which emerged within UNESCO in the 1970s as a reaction of Third World nations to colonialism and the economic and cultural influence of Western nations. Finally, it is argued that, despite the failure of NWICO in the past, the concept has not lost relevance and it would be reasonable to bring it back to the international agenda.}, subject = {Brasilien; Postkolonialismus; Filmanalyse; Stereotyp; Postkolonialismus; Medienkonzentration; Stereotype; Filmanalyse; NWICO; Postcolonialism; Media concentration; Stereotypes; Film analysis; NWICO}, language = {en} } @phdthesis{Angwafo2006, author = {Angwafo, Tsi Evaristus}, title = {Status of wildlife and its utilisation in Faro and Benou{\´e} National Parks North Cameroon : Case study of the Derby Eland (Taurotragus derbianus gigas Gray, 1947) and the African Wild Dog (Lycaon pictus Temminck, 1840)}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-111}, school = {BTU Cottbus - Senftenberg}, year = {2006}, abstract = {Primary and secondary data were collected during the period of January - May 2005 and questionnaires were issued between August - December 2004 to know the Status of Wildlife and its Utilisation in Faro and Benou{\´e} National Parks North Cameroon: Case study of the Derby Eland (Taurotragus derbianus gigas Gray, 1947) and the African Wild Dog (Lycaon pictus Temminck, 1840). The line transect method was used to assess wildlife population. Geographical Information System (GIS) maps of Faro and Benou{\´e} National Parks were drawn to show their distribution. Eleven different wildlife species were studied in Faro and Benou{\´e} National park. The density of Kobus kob in Faro was 0.39 animals/km² and 0.28 animals/km² in Benou{\´e} and that for Acelaphus buselaphus was 0.4 animals/km² in Benou{\´e} National park. The encounter rate was calculated for all other species and it was weak in Faro ranging from 0.009 - 0.01 while in Benou{\´e} it was higher ranging from 0.03 - 0.87. The highest encounter rate was from Benou{\´e} National Park for Loxodonta africanna. The total biomass for wildlife was 13,224.4 kg/km² with the higest percentage contribution of which 60.49\% coming from Taurotragus derbianus gigas in Faro National Park.The total biomass in Benou{\´e} National Park was 37, 1839 kg/km² with the biomass for Taurotragus derbianus gigas as 20 kg/km² and percentage contribution of 9.68\%. The higest percentage contribution to the total biomass in Benou{\´e} National Park was 85.52\% coming from Loxodonta Africana. No observations or trace of the Lycaon pictus was seen in the two parks (Faro and Benou{\´e}) within the study period. Removal and replacement rates of Taurotragus derbianus gigas showed a polynomial shaped curve with periods of population increase and decrease with regards to yearly behaviour while the previewed Lycaon pictus for hunting showed a polynomial shaped curve while its actual removal dwindled on a straight line. Removal and replacement is not influenced by sport hunting activities alone but prey availability, absence and presence of predators, disease, car accidents and other human influences. However, the critical value for the exploitation (sport hunting) of wildlife over a period of 20 years in Faro and Benou{\´e} National Parks was necessary to be determined though it was a difficult attempt. Income generated from park activities had doubled from 42.8 million F CFA to 92.5 million F CFA in 2001. Categories of hunters coming to the parks for hunting activities were 90\% non-residents, 6\% residents and 4\% nationals hunting by permit. The estimated annual revenue from wildlife was 91,185.00 Euros and 773,685.00 Euros in Faro and Benou{\´e} National Parks respectively. Taurotragus derbianus gigas had the highest value of 19,400 Euros in Faro National Park and 87,000 Euros in Benou{\´e} National Park. Both parks contribute 0.58\% of the total revenue generated by wildlife in Faro and Benou{\´e}. There was a high level of awareness about conservation of the Taurotragus derbianus gigas and the Lycaon pictus. Also was a general willingness to pay for the conservation of resources though it was an issue of a social dilemma of choosing between self interest and collective gains. However, the population was willing to pay 500 F CFA to generate a conservation fund to sustain identified conservation projects. Assessing the management policy of the government, 40\% of the population wish to be compensated for giving away their resource while 28\% opt for exchange, 9\% expropriation, 16\% continuation and 1\% had indicated no option (neutral).}, subject = {Kamerun; Nationalpark; Wildtiere; Wildbestand; Cameroon; National park; Wildlife population}, language = {en} } @phdthesis{Antoshkiv2007, author = {Antoshkiv, Oleksiy}, title = {Untersuchung der Z{\"u}ndung in einer neuartigen gestuften Brennkammer}, isbn = {978-966-603-540-3}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-3739}, school = {BTU Cottbus - Senftenberg}, year = {2007}, abstract = {Im Rahmen dieser Arbeit wurden die Z{\"u}ndungseigenschaften einer neuartigen Brennkammer untersucht, wobei auch das Magerverl{\"o}schverhalten mit in Betracht gezogen wurde. Die Untersuchungen der Z{\"u}ndbarkeit basieren auf den Ergebnissen numerischer Simulationen und anschließenden Auswertungen in einer Z{\"u}ndsubroutine. Die Ergebnisse der Str{\"o}mungssimulationen sind mit PIV-Messungen experimentell validiert worden, wobei die simulierten Sprayformen durch die ermittelten Mie-Aufnahmen best{\"a}tigt wurden. Hochgeschwindigkeitskamera - Aufnahmen wurden zur Validierung der berechneten minimalen Z{\"u}ndenergien verwendet. Die vorgenommenen Korrelationen zwischen den kalkulierten Werten der minimalen Z{\"u}ndenergie sowie den gemessenen AFR-Z{\"u}ndungsdaten er{\"o}ffnen einen Weg zur Bestimmung der zu erwartenden z{\"u}ndbaren Gemischkonzentrationen in realen Brennkammern aufgrund der simulierten minimalen Z{\"u}ndenergie. Im Rahmen der Arbeit wurde weiterhin eine Parametergewichtung durchgef{\"u}hrt, welche als Grundlage bei der Optimierung {\"a}hnlicher Brennkammern dienen kann.}, subject = {Triebwerk; Brennkammer; Z{\"u}ndung; Triebwerk; Brennkammer; Z{\"u}ndung; Aero engine; Combustor; Ignition}, language = {de} } @phdthesis{Antwi2009, author = {Antwi, Effah Kwabena}, title = {Integrating GIS and remote sensing for assessing the impact of disturbance on habitat diversity and land cover change in a post-mining landscape}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-7825}, school = {BTU Cottbus - Senftenberg}, year = {2009}, abstract = {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 S{\"u}d. 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 S{\"u}d 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 S{\"u}d 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 S{\"u}d 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.}, subject = {Landschaftsbewertung; Landschaftsanalyse; Fernerkundung; Geoinformationssystem; GIS; Fernerkundung; Landschaft; Fragmentierung; Reklamation; GIS; Remote sensing; Landscape; Fragmentation; Reclamation}, language = {en} } @phdthesis{Apau2017, author = {Apau, Kwaku Boakye}, title = {Developing a conceptual solution for domestic wastewater management in developing countries: Kumasi (Ghana) as a case study}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-41544}, school = {BTU Cottbus - Senftenberg}, year = {2017}, abstract = {Wastewater treatment systems abound as a result of technological improvements in treatment processes. Therefore in the selection of a wastewater treatment system for a particular wastewater treatment situation there are many alternatives to choose from. Despite this development municipal wastewater treatment in communities in developing countries are not always sustainable due to the application of inappropriate treatment systems. The question is how can an appropriate treatment system be identified for a certain location? The answer to this question is of importance to developing countries where wastewater treatment is usually not sustainable. In this study a framework for assessing wastewater treatment systems was developed. First, a comprehensive set of indicators representing parameters of treatment systems and properties of the study area that impacts on wastewater treatment were identified. Secondly, assessment of these indicators were carried out through expert and community survey to identify a final set of indicators whose composition consist of efficiency, reliability and simplicity of treatment systems and resource constraint, resource recovery and environmental concerns of the study area. Thirdly, four wastewater treatment systems, namely: Waste Stabilization Ponds, Trickling Filter, reed bed and free water surface Constructed Wetlands considered to be feasible for the study area were evaluated by the application of the identified indicators. Finally, a decision matrix produced was processed by multi-attribute decision making methods using two indicator weights to identify the most appropriate treatment system among the four alternatives. Results of the study show that in a scenario where equal indicator weights are assumed, reed bed is identified as the most appropriate with stabilization ponds being ranked as the least appropriate. In a more practical scenario where the weights of the indicators are allocated to reflect conditions of the study area, free water surface is ranked as the most appropriate. This outcome is at variance with stabilization pond technologies currently installed at communities in the study area. The performance of constructed wetlands is at the midpoint as far as most of the high to medium weighted assessment indicators are concern. It therefore represents a compromising solution between waste stabilization pond and trickling filter. The study also shows a change in variants of constructed wetland with a change in indicator weights. An indication that the decision situation determines the appropriateness of a treatment system and not the treatment system itself. The selection framework employed in this study can be said to be reliable and capable of identifying a treatment system that can be appropriate for a particular location. This is because the choice of a constructed wetland for the study area fits the definition of appropriate treatment system defined by the final indicators identified in this study.}, subject = {Wastewater treatment; Treatment efficiency; Land requirement; Multi-attribute decision making; Assessment indicators; Behandlungseffizienz; Bodenbedarf; Abwasserbehandlung; Entscheidungsfindung f{\"u}r Mehrfachattribute; Bewertungsindikatoren; Entwicklungsl{\"a}nder; Abwasserreinigung; Umweltbewertung}, language = {en} } @phdthesis{Apte2020, author = {Apte, Anisha}, title = {A new analytical design method of ultra-low-noise voltage controlled VHF crystal oscillators and it's validation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-51386}, school = {BTU Cottbus - Senftenberg}, year = {2020}, abstract = {The design of high Q oscillators, using Crystals at lower frequencies, (and dielectric resonators at much higher frequencies), has long been considered a black art. This may be due to the fact that a systematic approach with optimized design guideline for crystal oscillators could not be found after extensive literature search. In this dissertation, after analyzing the first crystal oscillator by W.G. Cady (1921), other high performance crystal oscillators will be discussed, analyzed and calculated. A single transistor crystal oscillator design as used by HP (Hewlett Packard) in one of their designs, the HP10811A is considered in this thesis for mathematical analysis and CAD (Computer aided Design) simulation. This was also measured on state-of-the-art signal source analyzer. After validation, this design is scaled to 100MHz, the frequency of interest for this dissertation. Though most designers use a single transistor based oscillator circuit, it is not an optimized design because of limited control over key design parameters such as loop gain, dc current etc. This dissertation is an attempt to overcome the limitation due to the single transistor circuit and to give a step by step procedure, explaining the significance of a two transistor design with thorough analysis and design simulation results. This two stage transistor circuit is also not yet a best solution in terms of phase noise performance and output power, and some add-on circuitry will be needed for an optimized performance. An important contribution of this work is to show that since the voltage gain is the ratio of the collector resistor and the emitter resistor, the performance is practically independent of the VHF transistor and gives better control over various parameters of the oscillator, in order to optimize the design. A grounded-base amplifier is then introduced and added for improving the isolation and the output power. Unlike most oscillators, that take the output from the collector, a novel concept introduced by Rohde [14], is incorporated here, where the crystal is used as a filter that is then connected to the grounded base amplifier, a technique which many companies have been using. This dissertation will show that this technique increases the output power without significantly affecting the phase noise. Such a validation is needed for better understanding and as per my knowledge, has not been done so far. For the oscillator, the tuning diode sensitivity and flicker noise contribution are also taken into consideration, by calibrating the mathematics and its validation is shown. Crystal resonators of the type AT and stress-compensated (SC) cut devices will be considered as they give the best performance. The one port Colpitts type oscillator is considered first and the two port two transistor design later. Both will need a post amplifier/buffer stage. A complete step by step design procedure for an optimized 100MHz crystal oscillator is then presented. For completeness, CAD Simulation and Experimental results are provided for 10 MHz, 128 MHz and 155 MHz VCO circuits.}, subject = {Quartz crystal; Crystal oscillator; Phase noise; Reference source; Voltage controlled; Quarzkristall; Kristalloszillator; Phasenrauschen; Referenzquelle; Spannungsgesteuert; Quarzoszillator; UKW; CAD}, language = {en} } @phdthesis{Arguirov2007, author = {Arguirov, Tzanimir Vladimirov}, title = {Electro-optical properties of dislocations in silicon and their possible application for light emitters}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-5837}, school = {BTU Cottbus - Senftenberg}, year = {2007}, abstract = {This thesis addresses the electro-optical properties of silicon, containing dislocations. The interest in those properties is driven mainly by two practical reasons. One is the optical characterisation of multicrystalline silicon for solar cells, and the other is the design of light emitting diodes based on silicon by enhancement of silicon radiative properties via introduction of dislocations. The work demonstrates that dislocation specific radiation may provide a means for optical diagnostics of solar cell grade silicon. It provides insight into the mechanisms governing the dislocation recombination activity, their radiation, and how are they influenced by other defects present in silicon. We demonstrate that photoluminescence mapping is useful for monitoring the recombination activity in solar cell grade silicon and can be applied for identification of contaminants, based on their photoluminescence signatures. It is shown that the recombination at dislocations is strongly influenced by the presence of metals at the dislocation sites. The dislocation radiation activity correlates with their electrical activity. Thus, photoluminescence mapping at room temperature may provide a means for revealing and characterising of dislocation-rich regions in multicrystalline silicon. It is shown that the dislocation and band-to-band luminescence are essentially anti-correlated. The band-to-band intensity being related to the diffusion length of minority carriers can be used for measurements of diffusion length, as long as the surface recombination rate is controlled. Moreover, photoluminescence mapping can be used for the detection of optically active defects in solar grade materials. Thus, betaFeSi2 precipitates, with a luminescence at 0.8 eV, were detected within the grains of block cast materials. They exhibit a characteristic feature of quantum dots, namely blinking. The second aspect of the thesis concerns the topic of silicon based light emitters for on-chip optical interconnects. The goal is an enhancement of sub-band-gap or band-to-band radiation by controlled formation of dislocation-rich areas in microelectronics-grade silicon as well as understanding of the processes governing such enhancement. For light emitters based on band-to-band emission it is shown, that internal quantum efficiency of nearly 2 \% can be achieved, but the emission is essentially generated in the bulk of the wafer. On the other hand, light emitters utilizing the emission from dislocation-rich areas of a well localized wafer depth were explored. Three different methods for reproducible formation of a dislocation-rich region beneath the wafer surface were investigated and evaluated in view of their room temperature sub-band-gap radiation: (1) silicon implantation and annealing, (2) epitaxially grown SiGe buffer, and (3) direct wafer bonding. The most promising dislocation-based emitter appears the utilization of a dislocation network produced by wafer bonding. It is shown, that monochromatic D1 radiation (wavelength 1.5 µm) can be generated in a well localised depth of the wafer. The radiation is not absorbed in silicon and such localized emitter can, potentially, be coupled with silicon waveguides and Ge-based detectors for optical interconnects.}, subject = {Silicium; Versetzung ; Lumineszenz; Lumineszenz; Versetzungen; Silizium; Luminescence; Dislocations; Silicon}, language = {en} } @phdthesis{AsanteAnnor2012, author = {Asante-Annor, Asare}, title = {Scientific principles for the protection of groundwater resources in Ghana}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-26707}, school = {BTU Cottbus - Senftenberg}, year = {2012}, abstract = {Groundwater is an important resource in Sub-Saharan Africa to supply water for domestic, industrial, mining and irrigation for agricultural purposes. In Ghana, groundwater supply program is mostly pragmatic to give people drinking water, however to ensure sustainability a long term groundwater management system is essential. One such approach is the use source protection (well protection) with the declaration and installation of protection zones. To achieve the goal of this research three hypothetical questions were asked which relates to the Availability and Vulnerability of groundwater, and the use of an analytical model to estimate source protection zones (SPZ). The regions of Adansi, Lawra, Sunyani and Sekyere West were chosen as study areas to test the hypothesis of this research with detailed investigation concentrating on Adansi area. The overall aim from the study areas was to estimate SPZ for Granite, Phyllite, Schist, Sandstone and weathered materials and give recommendations as to which activity should be permitted or otherwise within each of these zones. The available groundwater for a particular well or location was determined based on its hydraulic conductivity and specific capacity of a well. Regionalization of the available groundwater was achieved by comparing the results of the hydraulic conductivity and specific capacity with the regional structural map. To determine the vulnerability of the available groundwater, the radius of influence (ROI) for the different boreholes was determined using Sichard and Dupuits formula whilst for Source protection zones, Darcy and the volumetric equation was used. Results of hydraulic conductivity estimated from pumping test data for the five major rock types showed a trimodal distribution (E-5, E-6 and E-7 m/s). There was a general trend of decreasing hydraulic conductivity to decreasing transmissivity. Results of plots of specific capacity verses hydraulic conductivity shows that only rock types with hydraulic conductivity greater than E-5 m/s yields sustainable groundwater supply. Three aquifer types were encountered in the study areas which were pore aquifers in shallow or alluvial, regolith and fracture aquifers in bedrocks. High hydraulic conductivity from the different rock types corresponds to higher ROI. The results of hydraulic conductivity, specific capacity, ROI and SPZ are used as input parameters for the estimation of the suitability of a groundwater source. A ranking matrix was developed for easy interpretation of hydrogeological data by combining the results of the input parameters into a single score. Results from the ranking matrix were used to determine specific regulations for the various aquifers in the study areas. Within the fractured crystalline rocks with k ≥E-5m/s siting of wells should target fracture zones whilst pumping during abstraction phase can exceed 15m3/s/m. The intermediate source protection zone should be at least 150m. Conclusions from the study could be applied in other areas of Ghana and be implemented during the initial development, abstraction and groundwater policy phases of other groundwater projects.}, subject = {Ghan; Grundwasser; Wasserwirtschaft; Umweltschutz; Gew{\"a}sserschutz; Grundwasser; Umweltschutz; Gef{\"a}hrdung; Verf{\"u}gbarkeit; Ghana; Groundwater; Protection; Vulnerability; Availability; Ghana}, language = {en} } @incollection{AscheidWangBirkeetal., author = {Ascheid, Gerd and Wang, Gaojian and Birke, Sebastian and Wehn, Norbert and Herrmann, Matthias and Wang, Yanlu and Hanay, Oner and Bayram, Erkan and Negra, Renato}, title = {LP100 : optimization of 100 Gb/s short range wireless transceivers under processing energy constraints}, series = {Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655}, booktitle = {Wireless 100 Gbps and beyond : architectures, approaches and findings of German Research Foundation (DFG) Priority Programme SPP1655}, doi = {10.26127/BTUOpen-5906}, publisher = {BTU Cottbus - Senftenberg}, pages = {1 -- 35}, abstract = {In 2012 a group of researchers proposed a basic research initiative to the German Research Foundation (DFG) as a special priority project (SPP) with the name: Wireless 100 Gbps and beyond. The main goal of this initiative was the investigation of architectures, technologies and methods to go well beyond the state of the art. The target of 100 Gbps was set far away from the (at that time) achievable 1 Gbps such that it was not possible to achieve promising results just by tuning some parameters. We wanted to find breakthrough solutions. When we started the work on the proposal we discussed the challenges to be addressed in order to advancing the wireless communication speed significantly. Having the fundamental Shannon boundary in mind we discussed how to achieve the 100 Gbps speed.}, subject = {100 Gbps; Wireless; Drahtlos; Short range wireless transceiver; Kurzreichweiten-Funk-Transceiver; Drahtloses Sensorsystem; Hochfrequenztechnik; Antenne; Terahertzbereich; Energieffizienz}, language = {en} } @phdthesis{Asegehegn2011, author = {Asegehegn, Teklay Weldeabzgi}, title = {Investigation of bubble hydrodynamics in gas-solid fluidized beds containing immersed horizontal tube banks for lignite drying application}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-23578}, school = {BTU Cottbus - Senftenberg}, year = {2011}, abstract = {In bubbling fluidized beds, bubble characteristics such as size, shape and velocity have a vital influence on the hydrodynamics of the bed and hence on its performance as a chemical reactor and/or a heat exchange unit. In many industrial applications such as lignite dryer heat transfer tubes are usually inserted to enhance the rate of heat and mass transfer and chemical conversion. However, their presence strongly influences the bubbling behavior of the beds. Therefore, reliable design and scale-up of these systems come only after fundamental understanding of the bubbling behavior is achieved. Therefore, in this research work the influences of tube bank geometries and particle size on bubble characteristics were thoroughly investigated. In this research work, both numerical and experimental studies were employed. For the experimental measurements, a new nonintrusive digital image analysis technique was developed. The technique allowed for the simultaneous measurements of bed expansion and various bubble properties. An in-house software was developed to fully automate the image acquisition and data processing procedure. For the numerical studies, the Eulerian-Eulerian two-fluid model based on the kinetic theory of granular flow was used. Though, this CFD model has been considered as a fundamental tool for modeling gas-solid fluidized beds, its quantitative validation remains insufficient for a wide range of reactor geometries and operating conditions. Therefore, in this work validation of the model using experimental measurements of bed expansion and bubble properties obtained from a pseudo-two-dimensional fluidized bed was performed. The influence of two-dimensional simulations and different modeling parameters such as the friction packing limit, drag model and solid-wall boundary conditions were investigated. The two-fluid model generally showed reasonable agreement with the experimental measurements of pressure drop, bed expansion and bubble properties in bubbling regime. However, as the gas superficial velocity is increased and the bed moved towards slugging and turbulent regimes a big deviation arose and the two-fluid model failed to predict reasonably the fluidized bed hydrodynamics for the freely bubbling bed. The mean bubble properties predicted by two-dimensional simulations were in reasonable agreement with experiments at lower superficial velocities. They deviated at higher bed height and this was more pronounced at higher gas superficial velocities. The results from three-dimensional simulations were in better agreement with the experimental measurements; however, the computational effort need was very high making them impractical for parametric studies and sensitivity analyses. It was also showed that the choice of friction packing limits, drag laws and specularity coefficients have little influence on the bubble properties. For a bubbling bed, both experimental measurements and numerical simulations showed that inserting horizontal tube banks had either no or marginal influence on the static bed pressure drop and bed expansion. On the other hand, bubble hydrodynamics were strongly influenced and controlled by the geometry of the immersed tubes. In freely bubbling fluidized beds bubble size as well as rise velocity increased with bed height and superficial velocity. In beds with immersed tubes, such general trends were completely disturbed. Tubes appeared to restrict rapidly growing bubbles. As a result the mean bubble diameter and rise velocity were lower in the vicinity of the tube banks than in the freely bubbling bed. Results from different particle sizes showed that in a freely bubbling bed increasing the mean particle size increased the bubble diameter and rise velocity as well as bed expansion. In fluidized beds with dense horizontal tubes on the other hand, the mean bubble properties were almost independent of the particle sizes.}, subject = {Wirbelschicht; Blase; Hydrodynamik; Zweiphasenstr{\"o}mung; Bildanalyse; Wirbelschicht; Blasenhydrodynamik; Eingetauchte horizontale Rohre; Two-Fluid Model; Automatisierte Bildanalyse; Fluidized Beds; Bubble Hydrodynamics; Immersed Horizontal Tubes; Two-Fluid Model; Digital Image Analysis Technique}, language = {en} } @article{AsliKimHoeschler2023, author = {Asli, Majid and Kim, Dongsuk and H{\"o}schler, Klaus}, title = {On the potentials of the integration of pressure gain combustion with a hybrid electric propulsion system}, doi = {10.3390/aerospace10080710}, year = {2023}, abstract = {As the issue of pollutant emissions from aviation propulsion escalates, research into alternative powertrains is gaining momentum. Two promising technologies are the Hybrid Electric Propulsion System (HEPS) and Pressure Gain Combustion (PGC). HEPS is expected to reduce pollutant emissions by decreasing fuel consumption, whereas PGC uses detonation in the combustor to increase the thermal efficiency of engines by elevating the total pressure during combustion. This study extensively explores the integration of these two emerging technologies, thoroughly assessing the advantages that arise from their combination. First, the renowned turboprop engine PW127 is benchmarked and modeled using Gasturb software. The model is integrated into Simulink using the T-MATS tool, with HEPS and pressure gain components added to analyze the thermodynamics of various configurations under different pressure gain values and HEPS parameters. The analysis, conducted up to the cruise phase of the baseline aircraft, reveals that applying pressure gain combustion through Rotating Detonation Combustion (RDC) results in a more significant increase in efficiency and decrease in fuel consumption compared to HEPS with conventional gas turbines. However, HEPS helps maintain a more uniform combustor inlet condition and reduces the Turbine Inlet Temperature (TIT) at the takeoff phase, where the highest TIT otherwise occurs. The results suggest that integrating HEPS with PGC can be beneficial in maintaining optimal combustor conditions and mitigating turbine efficiency degradation.}, subject = {Pressure gain combustion; Hybrid electric propulsion; Rotating detonation combustion; Druckverst{\"a}rkungsverbrennung; Rotierende Detonationsverbrennung; Hybrid-Elektroantrieb; Propeller-Turbinen-Luftstrahltriebwerk; Hybridantrieb; Verbrennung; Schadstoffemission; Emissionsverringerung}, language = {en} } @phdthesis{Asong2010, author = {Asong, Fred Zisuh}, title = {Recycling and material recovery in Cameroon: Implications for poverty alleviation and ecological sustainability}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-18979}, school = {BTU Cottbus - Senftenberg}, year = {2010}, abstract = {Recycling and material recovery are gaining more grounds in applicability as viable options to sustainable solid waste management especially in Municipal Solid Waste Management (MSWM) schemes. In this dissertation a critical analyzes is made of the MSWM problem in Cameroon and an assessment of the role Small- and Medium-Size Enterprises have been playing in the area of recycling and material recovery. The main research methods applied in this research include: fieldwork, administration of questionnaires, interview and literature review. Using two case study localities (Limbe and Buea municipalities), the various practices in MSWM are elaborated, the constraints and challenges faced by management discussed and proposals for either expanding/upgrading existing schemes to be more sustainable as well as strategies to initiate new systems presented. Innovations within collection systems such as the introduction of household bins and specialized collection of specific waste could be quite beneficial to existing schemes. Waste Electrical and Electronic Equipment (WEEE) which constitute one of the fastest growing waste streams presents greater management challenges. Two case study localities (Buea and Kumba) are used to analyze the problem of WEEE in Cameroon. An overview of the handling of Electrical and Electronic Equipment (EEE) at end-of-life (EoL) in Cameroon is made with special focus on households and repair units. At household level, WEEE is disposed of alongside other waste arisings in the available disposal facilities for given household. Repair units represent a very vital connection between dysfunctional EEE and EoL forms as all users of EEE tend to bring these devices to these units for repairs. An inventory of the various EEE at repair units for these two localities shows that above 40\% percent of such equipments are totally out of use. In Kumba, Classes 1 and 4 EEE (according to EU WEEE directive classification) dominate while class 3 is almost absent. In Buea, Class 3 and 4 are dominant. These results show that socio-cultural, economic and even climatic factors influence the choice of EEE that people in this area acquire. The intense level of repair activities and recovery of useful parts by repair units show that there exist adaptable options to handle WEEE in especially economically and environmentally beneficial ways. The recycling of aluminum for production of household utensils represents a very basic and adaptive industrial set-up, which can easily be operated and run at very cheap cost and with a little manpower. While this venture seems apparently successful in economic terms as an option to poverty alleviation through income generation, it is plagued by some problems which, if given due consideration will render it a prospective option for poverty alleviation (through small enterprise business development) and environmental sustainability (as an option to sustainable MSWM). In this dissertation, a model is thus presented, which can be utilized by stakeholders to improve on the sector. An assessment of efforts and constraints to implementing comprehensive recycling and recovery schemes in Cameroon was also carried out. Results show that there are existing practices on which comprehensive recycling and recovery can be built upon that would be beneficial to both councils and engaged schemes - mostly SMEs and NGOs. The challenges faced and likely to be faced and the way forward to implementing any broad scale recovery and recycling are presented. If municipal councils choose to operate existing MSWM schemes without significant changes, then collective collaboration will be highly required. Such collaboration will present benefits to both waste collection and disposal. On the other hand, if they wish to expand schemes or create new schemes, adaptive innovation would be highly recommended. Such adaptive innovation would have to incorporate local practices and approaches of MSWM as well as socio-economic considerations so as to ensure new or expanded schemes survive within local socio-economic context. A greater challenge in enhancing recycling and material recovery in particular and MSWM in general, in Cameroon is on the role the government takes on designing appropriate policies and legislative frameworks to cover such activities in economically and ecological beneficial ways. In the absence of these, SMEs, councils and NGOs (working in partnership with other specialized groups) concerned with activities related to recycling and material recovery may be left with the option of regulating activities within their sectors as such activities stand to alleviate poverty and also present ecological benefits.}, subject = {Kamerun; Armut; Recycling; Nachhaltige Entwicklung; Abfallwirtschaft; Recycling; Wiederverwertung; Armut; Nachhaltigkeit; Kamerun; Recycling; Recovery; Poverty; Sustainability; Cameroon}, language = {en} } @phdthesis{Assaf2021, author = {Assaf, George}, title = {Fuzzy coloured Petri nets for modelling biological systems with uncertain kinetic parameters}, doi = {10.26127/BTUOpen-5851}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-58516}, school = {BTU Cottbus - Senftenberg}, year = {2021}, abstract = {Over the last twenty years, Petri nets have been increasingly adopted for modelling and simulating biological systems, as they offer an intuitive and graphical approach for this purpose. Their usability convenience comes from the fact that they offer many types of elements to describe systems in a qualitative and quantitative way. Coloured Petri nets are particularly useful to model systems with repeated components in a compact fashion. Our tool Snoopy for modelling and simulating Petri nets is one of the most well-known tools supporting a family of related Petri net classes comprising stochastic, continuous and hybrid Petri nets, and covering uncoloured and coloured Petri nets alike. However, kinetic information of a biological system, i.e. kinetic parameters may be uncertain, due to many reasons, e.g. environmental factors. Besides, coloured Petri nets as they were previously supported in Snoopy suffered from some inconsistencies. Due to these inconsistencies, exploring the model behaviour using different sizes (scaleability) was not feasible. Both challenges call for a new and more powerful approach integrating the modelling of uncertainties together with modelling features supporting repeated structures in a compact and scalable way. This thesis comprises two major contributions: Firstly, we introduce the definition and present the simulation algorithm for both uncoloured and coloured fuzzy Petri nets, by extending the existing quantitative uncoloured and coloured Petri nets in Snoopy. This includes discretising the uncertain kinetic parameters to crisp values by using sampling strategies. Secondly, we harmonise coloured Petri nets in Snoopy with their uncoloured counterparts and we extend the Snoopy's coloured Petri nets by all the features, which are supported by the coloured abstract net description language - an exchange format of coloured Petri nets in our PetriNuts tool family. By performing fuzzy simulation, one can obtain two kinds of output: fuzzy bands of each output variable and their corresponding timed-membership functions. Each fuzzy band describes the uncertainties associated with the input, whereas membership functions give more accurate information about the associated uncertainties. The most important features that we obtain by harmonising coloured Petri nets are to develop scaleable models, by defining scaling factors as constants and unifying the usage of coloured Petri nets with the other tools in our PetriNuts tool family.}, subject = {Uncertain biological systems; Petri nets; Fuzzy logic; Colouring fuzziness; Software harmonisation; Unbestimmte Systembiologie; Modellierung; Petri-Netze; Software Hamonisierung; Simulation; Gef{\"a}rbtes Petri-Netz; Systembiologie; Fuzzy-Logik}, language = {en} } @techreport{AuerDosaDulaietal.2019, author = {Auer, Peter and D{\´o}sa, Gy{\"o}rgy and Dulai, Tibor and F{\"u}genschuh, Armin and N{\"a}ser, Peggy and Ortner, Ronald and Werner-Stark, {\´A}gnes}, title = {A new heuristic and an exact approach for a production planning problem}, editor = {F{\"u}genschuh, Armin}, issn = {2627-6100}, doi = {10.26127/BTUOpen-4827}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-48278}, year = {2019}, abstract = {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.}, subject = {Production planning; Mixed-integer programming; Heuristics; Simulation; Fertigungsprogrammplanung; Heuristik; Optimierung}, language = {en} } @phdthesis{Augustin2012, author = {Augustin, Michael}, title = {Spezifische Fehlertoleranz f{\"u}r kombinatorische und sequentielle Schaltungen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus-26931}, school = {BTU Cottbus - Senftenberg}, year = {2012}, abstract = {In dieser Arbeit wird ein neues Konzept f{\"u}r den Entwurf fehlertoleranter digitaler Schaltungen vorgestellt. Die als spezifische Fehlertoleranz bezeichnete Entwurfsmethode erweitert den Stand der Technik um die M{\"o}glichkeit, Fehlertoleranz gezielt f{\"u}r gew{\"u}nschte Ein- und Ausgabezuweisungen einer Schaltung bereitzustellen. Die generell sehr aufw{\"a}ndigen Maßnahmen zur Realisierung von Fehlertoleranz lassen sich so an die tats{\"a}chlich vorhandenen Zuverl{\"a}ssigkeitsanforderungen einer gegebenen Anwendung anpassen, was im Vergleich zu herk{\"o}mmlichen Verfahren zu erheblichen Kosteneinsparungen im Hinblick auf Hardware und Stromverbrauch f{\"u}hrt. Die Eingaben einer Schaltung werden dazu mit ihren zugeh{\"o}rigen Ausgaben in kritische und unkritische Signale unterteilt. F{\"u}r kritische Signale wird das gleiche Maß an Fehlertoleranz bereitgestellt, wie es auch durch das Verfahren der dreifach modularen Redundanz garantiert wird. Unkritische Signale werden nicht fehlertolerant ausgelegt, da das f{\"u}r solche Signale nicht gefordert werden muss. Im Bezug auf kombinatorische Schaltungen wird dieses Grundprinzip auf eine beliebig w{\"a}hlbare Teilmenge aller m{\"o}glichen Eingaben mit ihren zugeh{\"o}rigen Ausgaben angewendet. Die nicht zu sch{\"u}tzenden, unkritischen Signale werden zu Optimierungszwecken genutzt. Genau diese Freiheit im Entwurfsprozess erm{\"o}glicht beim Entwurf fehlertoleranter Schaltungen signifikante Kosteneinsparungen, die bislang durch andere Verfahren nicht ber{\"u}cksichtigt wurden. Bei sequentiellen Schaltungen wird das Konzept auf Eingabefolgen und ihre entsprechend zugeh{\"o}rigen Ausgabefolgen abgebildet. Ab einem bestimmten Zustand werden in Schaltungen, die nach diesem Prinzip entworfen wurden, alle als kritisch eingestuften Eingabefolgen fehlertolerant verarbeitet, woraufhin die sequentielle Schaltung entsprechend fehlertolerante Ausgabefolgen liefert. Die L{\"a}nge der kritischen Eingabefolgen und die Anzahl der Zust{\"a}nde, von denen aus eine fehlertolerante Verarbeitung der Eingaben gefordert wird, ist beliebig w{\"a}hlbar. Neben der Beschreibung des Grundkonzeptes der spezifischen Fehlertoleranz f{\"u}r kombinatorische und sequentielle Schaltungen beinhaltet die Arbeit Erweiterungen, mit denen sich die durch das Verfahren bereitgestellte Fehlertoleranz erh{\"o}hen l{\"a}sst. Es wird zudem erl{\"a}utert, wie die spezifische Fehlertoleranz ohne besonderen Aufwand mit Hilfe g{\"a}ngiger Werkzeuge im Schaltungsentwurf umgesetzt werden kann. Vom Entwerfer werden dazu keine speziellen Kenntnisse {\"u}ber das eigentliche Verfahren vorausgesetzt. Anhand experimenteller Ergebnisse wird auch gezeigt, welche Einsparungen sich durch die spezifische Fehlertoleranz im Vergleich zu herk{\"o}mmlichen Verfahren aus diesem Bereich ergeben. Dazu wurden verschiedene Benchmark-Schaltungen mit der spezifischen Fehlertoleranz implementiert und ihre Gesamtfl{\"a}chen den Fl{\"a}chen entsprechender Schaltungen, die nach dem Prinzip der dreifach modularen Redundanz entworfen wurden, gegen{\"u}bergestellt.}, subject = {Integrierte Schaltung; Zuverl{\"a}ssigkeit; Fehlertoleranz; Fehlertoleranz; Dreifach modulare Redundanz; Fl{\"a}chenreduzierung; Digitalschaltung; TMR; Fault tolerance; Triple modular redundancy; Reduction of area; Digital circuit; TMR}, language = {de} } @book{Autenrieth2015, author = {Autenrieth, Edmund ¬von}, title = {Die statische Berechnung der Kuppelgew{\"o}lbe}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:co1-opus4-35646}, publisher = {BTU Cottbus - Senftenberg}, year = {2015}, abstract = {Digitalisat von: 98-07719 - Autenrieth, Edmund ¬von: Die statische Berechnung der Kuppelgew{\"o}lbe}, subject = {Kuppel; Baustatik; Berechnung}, language = {de} }