Refine
Document Type
- Issue (periodical) (3175)
- Doctoral thesis (828)
- Book (84)
- Report (67)
- Conference proceeding (56)
- Working paper (46)
- Master thesis (33)
- Scientific article (32)
- Bachelor thesis (30)
- Habilitation thesis (18)
Is part of the Bibliography
- no (4395) (remove)
Year of publication
Language
- German (3767)
- English (619)
- Multiple languages (5)
- French (4)
Keywords
- Architektur (2323)
- Bauingenieurwesen (2269)
- Bauwirtschaft (2265)
- Architekturzeitschrift (2258)
- Bauwesen (43)
- Zeitschrift (42)
- Umweltbezogenes Management (35)
- Geschichte (31)
- Simulation (30)
- Energiewende (29)
Institute
- IKMZ (2373)
- Präsident*in (587)
- Präsident HL (263)
- FG Energieverteilung und Hochspannungstechnik (51)
- FG Systeme (41)
- FG Angewandte Physik und Halbleiterspektroskopie (36)
- FG Gewässerökologie (31)
- FG Stadtmanagement (30)
- FG Ingenieurmathematik und Numerik der Optimierung (29)
- FG Experimentalphysik und funktionale Materialien (28)
Eine Mangelernährung ist eine weit verbreitete, aber oft zu wenig berücksichtigte Komplikation bei Leberzirrhose-Patient/innen. Um dieses Phänomen identifizieren zu können, werden in der pflegerischen Praxis allgemeine Screening- und Assessmentinstrumente eingesetzt. Doch häufig findet keine differenzierte Nutzung dieser Skalen unter Berücksichtigung des Krankheitsbildes statt.
Ziel dieser systematischen Literaturübersicht war es, das am besten geeignete Mangelernährungsscreening- oder Assessmentinstrument in Bezug auf Patient/innen mit Leberzirrhose im Vergleich zu typischen Skalen der Ernährungsrisiko-Erkennung zu bestimmen.
Im Juni 2023 wurde eine Literaturrecherche in den Datenbanken PubMed und Cochrane Library sowie eine freie Handsuche in Google Scholar durchgeführt. Insgesamt konnten nach Filtereinstellungen 60 Treffer identifiziert werden. Im Anschluss des Titelscreenings, Lesen der Abstracts sowie Volltexte wurden zehn relevante Studien im Zeitraum von 2020 bis 2023 eingeschlossen.
Es konnten sieben relevante Screening- sowie vier Assessmentinstrumente identifiziert werden. Nach Überprüfung der psychometrischen Daten und der Empfehlungshäufigkeit bietet das speziell für Lebererkrankte entwickelte Assessmentinstrument RFH-NPT die zuverlässigsten Werte, um bei Patient/innen mit Leberzirrhose eine Mangelernährung identifizieren zu können. Das kann daran liegen, dass diese Skala unter anderem das Item „Berücksichtigung von Flüssigkeitsansammlungen im Körper“ beinhaltet.
Die inkludierten Studien weisen im Allgemeinen eine gute Qualität auf. Größtenteils konnten sich ähnelnde psychometrische Daten festgestellt werden. Es ist zu überprüfen, ob weitere Instrumente, wie zum Beispiel MNA-SF, zur Ernährungsrisiko- Bestimmung beim Krankheitsbild Leberzirrhose angewandt werden sollten.
Die Implementierung eines speziell für Leberzirrhose-Patient/innen angepassten Screening- oder Assessmentinstruments ist unabdingbar, um in der pflegerischen Praxis eine Mangelernährung zu identifizieren. Dadurch wird gewährleistet, dass mehr Menschen mit einem Ernährungsrisiko erkannt und schneller dem entgegenwirkende Maßnahmen eingeleitet werden. Letztlich kann dadurch das Outcome der Leberzirrhose-Patient/innen verbessert werden.
The central theme of this thesis revolves around the impacts of historic charcoal burning on todays soils and soil landscapes in Connecticut, USA. The first chapter gives an overview of the state-of-research regarding the spatial distribution, morphology and chemical- as well as physical soil composition of so called relict charcoal hearth (RCH) landforms. RCHs can be described as unique soil microhabitats in the context of flora and fauna growth. The central research aim of the thesis is led by the question: How and to what extend does the historical charcoal industry control the distribution, development and properties of present day soils in Connecticut, USA? This thesis presents results from two field-campaigns in 2017 and 2018 where 52 RCH sites were surveyed and sampled in Litchfield County, Connecticut. The resulting dataset comprises of more than 1245 soil samples from 154 soil profiles and detailed stratigraphic and morphometrical information for all RCH sites. RCH landforms result in three distinct soils: charcoal rich horizons (Auh horizons), mineral soil horizons dividing multiple Auh horizons horizontally (Cu horizons) and buried former topsoil’s (Ahb horizons) or buried mineral soil horizons (Bwb horizons). Sites on flat terrain (< 4° slope) have mostly one Auh horizon, while sites on steeper terrain (> 4° slope) have mostly two, sometimes up to three Auh horizons. The total volume of sites on slopes is positively correlated to the local slope, i.e. it increases with larger steepness of the terrain. Compared to reference soils, RCH soils are enriched in total soil organic carbon and especially in pyrogenic carbon. Vertical gradients of organic carbon concentrations in Auh and Cu horizons suggest an enrichment of non-pyrogenic organic matter in the topsoil and a vertical translocation of highly aromatic carbon compounds into intermediate and buried soil horizons. Furthermore, Auh horizons have a lower bulk density, a higher crystallinity ratio (Fed/Fet) of pedogenic iron oxides and are enriched in exchangeable elements (Ca2+, Mg2+, Mn2+) as well as oxalate extractable manganese-oxides compared to reference soils. A deep-learning based automated mapping workflow called ARCHMAGE (Automated Relict Charcoal Hearth Mapping and Geospatial Exploration) was created to gain a continuous, state wide database of RCH sites locations and other relevant geospatial information. This database, in combination with calculation of site specifics RCH volumes and soil carbon stocks, showed that in regions with high RCH site densities, significant additions to local soil organic and especially pyrogenic carbon stocks are present. This effect is scale dependent, with a larger effect size on county scale and below (≤ 1:650,000).
Die ökonomisch ausgerichteten Organisationsstrukturen und herausfordernden Arbeitsbedingungen im Krankenhaus prägen bereits seit mehreren Jahren den gesellschaftlichen und wissenschaftlichen Diskurs. Rund 61% des Pflegepersonals in der klinischen Versorgung leiden unter den sich immer weiter verstärkenden berufsbedingten psychischen Belastungen. Das hat enorme Auswirkungen auf die mentale Gesundheit der Pflegenden und führt zu überdurchschnittlich hohen krankheitsbedingten Arbeitsausfällen oder Fluktuationen. Aus diesem Grund stellen Maßnahmen zur Prävention von psychischen Belastungen eine wesentliche Komponente zur Steigerung der Arbeitszufriedenheit und Reduktion des Pflegenotstands dar. Die vorliegende Literaturübersicht soll einen Überblick über bestehende Präventionsmaßnahmen zur Reduktion und Bewältigung von psychischen Belastungen und deren belastungsassoziierten Auswirkungen bei professionell Pflegenden im Krankenhaus geben. Im Juni 2023 wurde eine systematische Literaturrecherche in den Datenbanken PubMed und PubPsych durchgeführt. Dabei wurden ausschließlich randomisierte kontrollierte Studien, welche im Zeitraum von 2020 bis 2023 veröffentlicht wurden und sich lediglich auf Interventionen für Pflegefachkräfte im klinischen Setting beziehen, eingeschlossen. Insgesamt konnten zehn relevante Forschungsarbeiten identifiziert und mithilfe der CASP-Checkliste bewertet werden. Basierend auf den Ergebnissen der inkludierten Studien ergaben sich sieben Kategorien präventiver Maßnahmen zur Minderung und Bewältigung von psychischen Belastungen bei Pflegefachkräften im Krankenhaus. Dabei handelt es sich um Maßnahmen der Verhaltensprävention, wie unter anderem Strategien zur Förderung von proaktiven Verhaltensweisen, des Zeit- und Stressmanagements oder der Resilienz. Alle Studien zielten auf die Verbesserung der mentalen Gesundheit und Reduktion des Belastungserlebens beim Pflegepersonal ab, wobei allerdings nur einige wenige Studien statistisch signifikante Effekte nachweisen konnten. Auffällig ist hierbei zudem, dass sich keine der Forschungsarbeiten mit Möglichkeiten zur Verhältnisprävention befasste. Die Entwicklung und Implementierung präventiver Maßnahmen zur Belastungsreduktion in der klinischen Pflege ist optimierungsbedürftig. Eine Kombination verhaltens- und verhältnisbezogener Maßnahmen sowie eine Veränderung der organisatorischen und institutionellen Rahmenbedingungen ist zwingend erforderlich. Eine Verbesserung der Arbeitsbedingungen ist unabdingbar, um die Effektivität verhaltensbezogener Maßnahmen zu gewährleisten und der Belastungssituation im Pflegeberuf präventiv begegnen zu können sowie das mentale Wohlbefinden der Beschäftigten nachhaltig zu fördern.
Mit der Zunahme von Häufigkeit und Intensität von Extremwetterereignissen werden die Folgen des Klimawandels auf lokaler Ebene sicht- und spürbar. Kommunen sind aufgefordert, Vorsorge zu betreiben und mit Anpassungsmaßnahmen den Folgen des Klimawandels zu begegnen. Von besonderer Bedeutung sind Anpassungsmaßnahmen dort, wo Schadenspotenzial und -risiko besonders hoch sind, so auch in historischen Altstädten. Gleichzeitig erfordert dieser Stadttypus besondere Sensibilität im Umgang mit der wertvollen Bausubstanz und einem oft einzigartigen Stadtbild. Einen konkreten Lösungsansatz im Umgang mit länger anhaltenden Trockenperioden auf der einen und Starkregenereignissen auf der anderen Seite bietet das Prinzip der Schwammstadt. Ziel des Forschungsvorhabens ist es, zu untersuchen, welche Elemente des Schwammstadtprinzips in welcher Weise in der historischen Stadt sinnvoll, Stadttypus-gerecht und wirkungsvoll sind. Im Kontext von baukulturell wertvoller städtebaulicher Struktur und Bausubtanz lautet das Motto hinsichtlich baulicher Eingriffe: „So wenig wie möglich, so viel wie nötig.“ Gleichzeitig gilt, dass die Kleinstadt im Vergleich zur Großstadt zwar einen „geringeren Grad an Ausdifferenziertheit ihrer Subsysteme“ aufweist, sie aber – ebenfalls im Vergleich zur Großstadt – nicht als defizitär betrachtet werden sollten. Neben Fragen nach Herausforderungen und Potenzialen der historischen Kleinstadt in Bezug auf die Anpassung an Klimawandelfolgen wird vor allem auf Lösungsansätze fokussiert, die dabei helfen, Schwammstadtprinzipien und denkmalgerechte Entwicklung miteinander zu kombinieren. Untersuchungsgegenstand sind die Kleinstädte der beiden kommunalen Arbeitsgemeinschaften Städte mit historischen Stadtkernen des Landes Brandenburg und Historische Stadt- und Ortskerne im Land Nordrhein-Westfalen. In der ersten Phase des Projektes wurden Daten mittels einer Online-Umfrage erhoben, die daraus gewonnenen Erkenntnisse durch die Untersuchung von Referenzstädten und Expert:innen-Interviews ergänzt, teilweise korrigiert bzw. klargestellt. Anschließend wurden die Ergebnisse dokumentiert und wiederum über Veranstaltungen in die Kleinstädte transferiert. Neben den klassischen wissenschaftlichen Methoden war ein Dialog mit und zwischen den Kleinstädten und der Austausch mit den Expert:innen zentrales Element des Forschungsvorhabens. Zu den zentralen Erkenntnissen zählt, dass für die meisten Kleinstädte die Anpassung ihrer historischen Altstadt an die Folgen des Klimawandels noch ein sehr neues Feld der Stadtentwicklungspraxis ist und sie dabei an personelle und finanzielle Grenzen stoßen. Zudem weist die historische Stadt- und Gebäudestruktur verschiedene hemmende Faktoren für die Umsetzung der Klimaanpassungsmaßnahmen auf, die eine behutsame Prüfung der realisierbaren Maßnahmen und eine individuelle Umsetzungsstrategie notwendig machen. Gleichzeitig bietet die historische Kleinstadt eine Vielzahl an Potenzialen, die den klimaadaptiven Umbau begünstigen und zum Teil relativieren.
Additive technologies are now widely used for the production of complex precise parts and have high potential for the production of forming dies. In this work, hot-forming dies optimized for additive manufacturing were developed and produced with wire arc direct energy deposition (WA-DED) and laser powder bed fusion (L-PBF) technologies. The concept of lightweight hot-forming dies with a 2D-lattice structure was developed, which reduced the weight of each die by 56%, from 14.2 kg to 6.1 kg, in production using L-PBF. Maraging/precipitation-hardened steel 17-4PH was used as an alternative to traditional hot-working steels with slightly lower mechanical properties and a much higher processability in the additive manufacturing process. The workability of the manufactured dies was confirmed by forging tests on an industrial screw press.
The very soft and flow-permeable plumage is among the special adaptations of the owl that the silent flight is attributed to. Using a specially designed apparatus that provides a low-speed volume flow of air through a small sample of porous materials, measurements of the air flow permeability were performed in accordance to ISO 9053 on a total of 39 prepared wing specimen from six different bird species, including three species of silently flying owls and three non-silently flying bird species. The resulting data set described in the present paper contains the static airflow resistance measured at different positions on the wing.
A classic approach for solving differential equations with neural networks builds upon neural forms, which employ the differential equation with a discretisation of the solution domain. Making use of neural forms for time-dependent differential equations, one can apply the recently developed method of domain segmentation. That is, the domain may be split into several subdomains, on which the optimisation problem is solved. In classic adaptive numerical methods, the mesh as well as the domain may be refined or decomposed, in order to improve the accuracy. Also, the degree of approximation accuracy may be adapted. Therefore, it is desirable to transfer such important and successful strategies to the field of neural-network-based solutions. In the presented work, we propose a novel adaptive neural approach to meet this aim for solving time-dependent problems. To this end, each subdomain is reduced in size until the optimisation is resolved up to a predefined training accuracy. In addition, while the neural networks employed are by default small, we propose a means to adjust also the number of neurons in an adaptive way. We introduce conditions to automatically confirm the solution reliability and optimise computational parameters whenever it is necessary. Results are provided for several initial-value problems that illustrate important computational properties of the method.
The Accra Metropolis of Ghana has experienced rapid urban expansion over the past decades. Agricultural and forest-lands have been transformed into urban/built-up areas. This study analysed urban expansion and its relationship with the temperature of Accra from 1986 to 2022. Multi-source datasets such as remote sensing (RS) and other ancillary data were utilised. Land use land cover (LULC) maps were produced employing the random forests classifier. Land surface temperature (LST) and selected d(RS) Indices were extracted. Regression techniques assessed the interplay between LST and remote sensing indices. The LULC maps revealed increasing trends in the urban/built-up areas at the expense of the other LULC types. The analysis from the LST and the RS indices revealed a direct relationship between temperature and urban/built-up areas and an inverse relationship between temperature and vegetation. Thus, spatial urban expansion has modified the urban temperature of Accra. The integrated utilisation of RS and GIS demonstrated to be an efficient approach for analysing and monitoring urban expansion and its relationship with temperature.
The permanent magnet synchronous motor (PMSM) can be a suitable candidate for electrified propulsion in aviation. Despite the very high efficiency, heat dissipation during operation leads to performance limitations. Elevated temperatures in the electrical insulations and the magnets pose a potential safety risk that must be reduced by selective cooling. A comprehensive review is conducted to capture current research interests in cooling methods in PMSM. Cooling methods are described according to their heat transfer mechanism, grouped, and assigned to the components within the motor. Key findings of the literature reviewed are described in the context of PMSM cooling. Information on cooling media and potential combinations of cooling methods in components is gathered. Assessment parameters such as safety, weight, effectiveness, integrability, complexity and cost are defined to enable a subsequent qualitative analysis for six selected cooling methods. A point-weighted evaluation approach, according to VDI 2225, was applied to identify the most promising cooling approach for successful implementation in aviation.
The present study deals with the phenomenological observation of the corrosion of the positive electrode foil of lithium-ion batteries containing LiNi0.6Co0.2Mn0.2O2 (NMC) as cathode material. Due to the presence of moisture, localized water accumulation is formed on the NMC surface. The water absorbed by the electrolyte reacts with the NMC under Li+/H+ exchange and the resulting pH increase leads to dissolution of the carrier foil and characteristic salt-like blooms on the NMC surface. With the increase in the relative area occupied by the holes in the aluminum foil per time, a sufficiently suitable parameter was found with which to quantitatively determine the extent of corrosion. The degree of degradation depends on time and ambient humidity. It was shown that functional recycling with the water jet method is no longer applicable for degraded foils, since the mechanical stability of the foils decreases as corrosion progresses. Lithium, aluminum, sulfur and oxygen were detected in the blooms using SEM–EDX and Laser-Induced-Breakdown-Spectroscopy (LIBS). The underlying NMC layer was found to contain mainly aluminum and significantly lower lithium content than the non-degraded material. SEM and Raman microscopy analyses also showed that the active material is also locally degraded and therefore no longer suitable for functional recycling.
Possible synergy between FLEGT-VPA & REDD+ towards improving forest governance framework in Cameroon
(2023)
Illegal logging is seen as a serious impediment to achieving sustainable management of forests in the tropics. In addition, deforestation contributes in increasing carbon dioxide emissions in the atmosphere, resulting to biodiversity loss and climate change. Illegal logging and deforestation have affected Cameroon’s forest ecosystem negatively since the mid-1980s as a result of the economic crises, which intensified the exploitation of forest resources for multiple purposes. In response, some policy initiatives came up such as FLEGT-VPA and REDD+ to fight against the threats. It is due to the above background that this study was designed to examine the possible synergy between FLEGT-VPA and REDD+ towards improving the forest governance framework in Cameroon. The first part of the study assesses FLEGT-VPA in Cameroon with the application of interviews of key informants who were involved in the negotiation process of the EU-Cameroon Voluntary Partnership Agreement. The second part of the study assesses the management of Bimbia Bonadikombo Community Forest (BBCF), as one of the REDD+ pilot project sites around Mount Cameroon in the South West Region of Cameroon. The use of surveys, content analysis, and observations seeks to assess these two initiatives in their role in improving forest governance in Cameroon. The first part of the research reveals that since Cameroon ratified the FLEGT-VPA in 2011, there has been progressed concerning stakeholder participation in forest-related issues. Again, the study also reveals challenges faced with the setting up of a system to verify timber from legal origin as recommended by the European Union. The research further reveals a lack of commitment by the government in revising the current forest policies and re-organizing the domestic market for timber trade as part of the commitment made by the government during the ratification of the FLEGT-VPA. The second part of the study finds that the management of BBCF is not governed by the provision of the Cameroon community forestry manual or by its bylaws posing doubts if community forestry can halt emissions of greenhouse gases caused by deforestation, thus helping REDD+ achieve its objectives. The study recommends the need for rapid policy reform and a cross-sectoral transformation to enable FLEGT-VPA and REDD+ to synergize for a better policy outcome on issues concerning forestry and climate change.
The next generation of civil turbofan engines targets the by-pass ratios of up to 20:1, requiring an innovative fan design with a low fan pressure ratio, low specific thrust and a radically increased fan diameter. The aerodynamic stability of such a large slow rotating fan is very sensitive against the back-pressure variations in the by-pass duct, especially during the take-off operations. The back-pressure regulation can be achieved significantly through a Variable Area Fan Nozzle (VAFN). This work deals with the design development of VAFN concepts for ultra-high by-pass ratio engines which was researched in EU funded program ENOVAL and received funding under grant agreement number 604999.
A system engineering approach was implemented for the VAFN development by following the requirements in conceptual, preliminary and detailed design phases. The design domains in the rear nacelle and under the core fairing were selected for the concept generation. Several qualitative and quantitative trade studies were conducted to down-select the best-fit solution during each design phase. These included the kinematic simulations of various types of VAFN modulations; analytical calculations to understand the thermodynamics of the selected VAFN kinematics; aerodynamic performance predictions using CFD simulations on a large number of preliminary designs; 3D CFD simulations for detailed performance assessments including the design optimization of individual features and distortions due to failed modulations; and FEM calculations for the topology generation and optimization of structural components. The overall weighted effect was determined for each output parameter and the results were presented in percentile changes relative to that with a fixed nozzle reference geometry.
Two VAFN concepts were selected for the final detailed design phase, Flaps in rear nacelle domain and Variable Inner Fairing Structure (VIFS). Both concepts showed better outputs in terms of specific fuel consumption, noise emission and fan’s safety margin during the take-off, with an over-area exhaust position than those with a fixed nozzle operation. During the climb phase, with an under-area VAFN position, both concepts resulted in drawbacks due to higher aerodynamic losses relative to the fixed nozzle. During MCR, both the VAFN concepts with stowed positions caused losses mainly due to leakages and higher structural weights relative to the fixed nozzle configuration. For each VAFN concept, a detailed system definition was developed and the function trees for each operation were explained. A discrete modulation type with two positions was described and recommended for both concepts. This included an over-area deployed position for the take-off phase and a stowed position for the rest of the flight, based on the beneficial performance of the VAFN concepts over the fixed clean nozzle configuration.
The creation of adequate simulation models for complex assemblies is an extensive process that requires a lot of experience, and on the other hand involves a multitude of manual, tedious tasks. These are significant obstacles for improving the process performance and capabilities. The objective of this research is to develop methods which digitally imitate the way of thoughts of the engineer in the design process towards a digital system understanding and which support the automation of the involved manual workflow.
This thesis presents a strategy to translate engineering reasoning and actions to an equivalent in the computer domain. A cardinal step is to gain understanding of system arrangements, boundary conditions and its components. Based on this evaluation, the identification of assembly parts is forming the foundation for optimized process chains for the transfer to the analysis environment. Model complexity relates to computational effort, which in turn affects model capabilities and manageability. To achieve a satisfactory compromise of model quality and complexity, this transfer process is strongly dependent on the visual analysis, reasoning and manual implementation of skilled engineers.
The principle of translating engineering logics is pursued from the assembly system to its smallest parts. Component segmentation methods allow subdividing regions of interest into substructures which are assigned with a feature vector. This vector comprises metrics describing the substructures with regard to specific aspects and is the key decision point for subsequent steps as idealization, suitable Finite-Element modeling and ultimately building an analysis model. The created system database is continuously maintained and supports these process chains as well as the final setup of the assembly simulation model.
An automated workflow like this implies advantages for efficiency, but also creates opportunities for further use cases. This workflow has been exploited for generating a training data set from the different simulation variants as a basis to a knowledge representation imitating engineering experience. An algorithm from the graph neural network field is applied to this data set as a conceptual approach. The intention pursued in this concept is to model the learning progress about estimating the influence of modelling decisions on simulation results and quality.
This research proposes a holistic strategy and describes methods to achieve the objectives of decreasing manual effort, introducing an automated and geometry-based process and digitally replicating engineering experience by introducing a knowledge database.
Assessing authenticity in heritage conservation : case study : architectural conservation in Bahrain
(2023)
The thesis complements the authenticity discourse in heritage conservation with the perspective of laypeople and evaluates the pertinent methodology for the application of the normative concept in architectural heritage conservation. Based on the Nara Document on Authenticity, the Operational Guidelines for the Implementation of the World Heritage Convention anchor the concept in the credibility and truthfulness of internal and external factors – referred to as information sources – that communicate a heritage site’s cultural values. Conversely, the author explored the truthfulness of messages conveyed to site users in a qualitative research based on interviews focused on two urban reference sites in Bahrain. These stand for different eras and conservation approaches: the ensemble of colonial-style governmental buildings at Bab al-Bahrain in Manama and the vernacular Siyadi Shops in the market area Suq al-Qaisariya in Muharraq, which were restored in the course of a World Heritage nomination. The interpretive content analysis compares how architects and non-architects, who represent laypeople in architectural conservation, perceived their authenticity and also traces cultural contingencies. The empirical data confirms pronounced differences in the way architects and non-architects perceive authenticity but only a few between representatives of so-called Western and Eastern cultures. Assessed against international heritage conservation standards, the site in Muharraq proved more authentic than the one in Manama. However, the meanings produced in the interaction between the sites and the interviewees proved be of limited truthfulness in both cases. A key finding is hence that a constructivist authenticity concept can serve no normative function when heritage conservation is considered a discipline at the service of historiography. While all potential factors of authenticity as per the Nara Document proved to be relevant, perceived material authenticity was found to be an outstanding reason why the site in Muharraq was appreciated more. Its rehabilitation was found to successfully reconcile essentialist and constructivist authenticity understandings by paying tribute both to the documentary value of the historic site and to the experiential needs of its users. The findings support the ICOMOS Venice Charter’s material-focused approach while confirming the relevance of a broadened authenticity understanding and highlighting the importance of integrated, participatory approaches to heritage conservation. By illustrating the importance of expertise when assessing the authenticity of architectural heritage, the findings at the same time flag limits to democratizing architectural conservation practice. The author recommends developing practice-oriented guidance for the assessment of authenticity of heritage sites based on further research and to add interpretation facilities to the list of factors of authenticity.
In the summer term 2020 the Chair of Urban Management, BTU Cottbus-Senftenberg, conducted an excursion for Master students of planning and architecture to the region on both sides of the border between Romania and Serbia in a format of distance learning. Over three days the students and local experts of various professional backgrounds engaged online in discussion on urban development in Timișoara, Novi Sad and Belgrade. We explored how the dynamics of changing physical and social boundaries shape urban territories in a tension between centrality and periphery, while also engaging with the paradigm shift in planning centred on culture and people’s participation, as well as anticipations from flagship culture schemes to trigger positive urban changes. This publication provides summaries of some of the contributions, illuminating urban development as a complex process which involves a plurality of geopolitical shifts, engaged actors, interests, perspectives, hope-filled approaches and instruments.
This thesis deals with strategies for achieving high data throughput in wireless sensor networks that use a time division multiple access (TDMA) scheme to resolve medium access. The thesis uses a multi-sided approach that deals not only with the scheduling algorithm but also with the network layer and the interference model. The thesis proposes four solutions that significantly improve data throughput, fairness, and latency in the considered scenario.
The thesis starts with an overview of state-of-the-art medium access control (MAC) protocols, emphasizing TDMA. Based on this overview, it is concluded that not much space for improvement is left in the field of schedule calculation algorithms; many such algorithms are proposed up to date, and they can achieve schedule lengths close to the theoretical minimum. However, the research also reveals a lack of in-detail evaluation and comparison of these algorithms; this makes choosing the most suitable algorithm for a particular application hard and performance estimation inaccurate. Therefore, an extensive evaluation of state-of-the-art TDMA protocols using simulations and over 200 randomly generated networks was performed to tackle this issue. The results allow choosing an appropriate algorithm and estimating performance for each specific application.
Next, the problem of multiple packet transmissions during a single time slot is analyzed. State-of-the-art TDMA protocols assume that one packet can be transmitted in each slot and optimize the number of slots each node gets under this assumption. However, when nodes can transmit more than one packet, the performance of such a schedule is impaired. To solve this, the M-TreeMAC protocol is proposed; this protocol considers the actual number of packets transmitted in a time slot and optimizes the schedule accordingly. Furthermore, it is observed that the routing topology heavily impacts the schedule length created using this algorithm; an algorithm that optimizes the topology to result in the shortest schedule when M-TreeMAC is used is proposed, increasing benefits even further.
Finally, the accuracy of the 2-hop interference model, commonly used by state-of-the-art TDMA scheduling algorithms, is studied and simulated using a realistic radio model based on measurement results. The results show high packet loss ratios for packets traveling a large number of hops to reach the sink. The adaptive interference model is proposed to improve the 2-hop interference model. The proposed model can increase throughput significantly in networks with a height of ten or more hops.
In dieser Dissertation wurden Zuverlässigkeitsaspekte der NED-Aktoren betrachtet und ihre Langzeitstabilität untersucht. Die Langzeituntersuchungen an einzelnen NED-Aktoren haben gezeigt, dass insbesondere große elektrische Felder zur Verkürzung der Lebensdauer der Aktorik führen können. Elektrische Felder beschleunigen Oxidation der NED-Siliziumelektroden. Dabei wurden zwei unterschiedliche Oxidationsmechanismen beobachtet: die anodische Oxidation von Siliziumelektroden im Isolatorbereich und die feldemissionsunterstützte Oxidation. Die beiden Degradationsmechanismen begünstigen das Wachstum des Siliziumoxides an Siliziumelektroden und resultieren in der Veränderung der Oszillationseigenschaften der NED-Aktoren mit der Zeit. Weitere Untersuchungen an den NED-basierten Anwendungen – Mikrolautsprecher haben verdeutlicht, dass solche Faktoren wie Feuchtigkeit die Degradation am meisten forcieren. Durch Passivierung der Aktoren, wobei sie z. B. mit Aluminiumoxid im ALD-Verfahren verkapselt werden, können unerwünschte Degradationsmechanismen deutlich verlangsamt werden. Durch eine geeignete Materialwahl bei der Verkapselung kann sogar gleichzeitig die Effizienz der Aktoren verbessert werden.
Das Phänomen Hatespeech gewinnt zunehmend Aufmerksamkeit in der Öffentlichkeit und in der Forschung. Das ist insofern wichtig, weil Hass, Hetze und Diskriminierung gegenüber Menschen, die einer bestimmten Gruppe zugeordnet werden, vor allem über Informations- und Kommunikationstechnologien eine gesamtgesellschaftliche Verrohung zur Folge hat. Hatespeech schränkt die Meinungsvielfalt ein und bedeutet eine Bedrohung für die Demokratie. Sie stellt jedoch kein reines Netzphänomen dar, sondern basiert auf real existierende Macht- und Diskriminierungsstrukturen. Das Phänomen einzudämmen, ist die Intention verschiedener Stiftungen und Initiativen. Hatespeech ist jedoch allgegenwärtig und selbst in der Schule verbreitet. Sie stellt damit eine Gefahr insbesondere für junge Heranwachsende und weiterführend für das alltägliche Schulleben dar. Somit stellt sich die Frage, welche Mittel der Institution Schule zu Verfügung stehen, um dem Phänomen wirksam entgegenzutreten. Im Zuge von präventiven und interventiven Maßnahmen stehen schulbezogene Programme im Vordergrund. Die vorliegende Masterthesis befasst sich daher mit einer ersten Bestandsaufnahme von deutschsprachigen, schulbezogenen Programmen zur Prävention und Intervention bei Hatespeech unter Kindern und Jugendlichen (Jahrgangsstufen 5 bis 12). Insgesamt konnten 14 entsprechende Programme im Rahmen der Recherchearbeit identifiziert werden. Diese wurden auf ihre Inhalte und Durchführungsmodalitäten sowie anhand von fünf ausgewählten Qualitätskriterien analysiert und hinsichtlich ihrer Anwendung in der schulischen Praxis beschrieben und erörtert. Die Übersicht über Schwerpunkte, Stärken sowie Entwicklungspotentiale schulbezogener Hatespeech-Programme soll eine informierte Entscheidung über den Einsatz der Programme in der Schule und darüber hinaus in der offenen Kinder- und Jugendarbeit ermöglichen.
Die Stadt Cottbus ist seit mehreren Jahren durch extrem rechte und verschwörungsideologische Mobilisierung herausgefordert. Auch in der Covid-19-Pandemie ist Cottbus Schauplatz regelmäßiger Demonstrationen. Mit Beginn des russischen Angriffskriegs auf die Ukraine verschiebt sich der inhaltliche Fokus der sogenannten Montagsspaziergänger sukzessive weg von der Pandemie und hin zum Krieg. Die hier vorliegende Forschung wendet sich den Protestveranstaltungen zu, die im Zeitraum vom 28. Februar bis 24. Oktober 2022 in Cottbus in Reaktion auf den russischen Angriffskrieg organisiert werden und untersucht unter Anwendung der Grounded Theory ausgewählte Redebeiträge. Sie zielt darauf ab, die Inhalte und Darstellungsweisen der RednerInnen hinsichtlich der Gefahrenpotentiale einzuordnen und im Sinne anwendungsbezogener Forschung in Richtung Prävention und zivilgesellschaftlicher Gegenwehr weiterzudenken. Die Forschung zeigt: Ähnlich wie in anderen ostdeutschen Städten sind auch in Cottbus die Veranstaltungen von extrem rechten Akteuren und Gruppen dominiert; sie werden unterstützt von Teilen eines bürgerlichen Milieus der sogenannten gesellschaftlichen Mitte. Sichtbar wird außerdem: Akteure aus dem Coronaprotestmilieu haben sich weiter radikalisiert; verschwörungs- und insbesondere reichsbürgerideologische Inhalte dominieren die untersuchten Veranstaltungen und mischen sich mit prorussischen Positionen und dem Ideologem einer „eurasischen“ Neuordnung des europäisch-asiatischen Raums. Die Ablehnung „des Westens“ bildet ein wiederkehrendes Metanarrativ.