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Remaining-useful-life (RUL) prediction of Li-ion batteries is used to provide an early indication of the expected lifetime of the battery, thereby reducing the risk of failure and increasing safety. In this paper, a detailed method is presented to make long-term predictions for the RUL based on a combination of gated recurrent unit neural network (GRU NN) and soft-sensing method. Firstly, an indirect health indicator (HI) was extracted from the charging processes using a soft-sensing method that can accurately describe power degradation instead of capacity. Then, a GRU NN with a sliding window was applied to learn the long-term performance development. The method also uses a dropout and early stopping method to prevent overfitting. To build the models and validate the effectiveness of the proposed method, a real-world NASA battery data set with various battery measurements was used. The results show that the method can produce a long-term and accurate RUL prediction at each position of the degradation progression based on several historical battery data sets.
Speedrunning in general means to go fast in a video game. This simple concept has an immense impact on the ways players engage with games. The inherent aspect of optimization within this esports niche makes it a good application field of optimization methods. This work gives an overview of speedrunning as an esports discipline. Prior works on this subject are discussed and assessed and relevant nomenclature is introduced. Using this information, routing --- the procedure of planning a speedrun --- is picked up as a graph optimization problem.
Nintendo's iconic game The Legend of Zelda: Ocarina of Time from 1998 is used as a working example to assess previous works and to explore more of this mainly uncharted field of research.To do so, the process of speedrun modeling is conducted as exhaustive as possible within the limits of a work like this. All relevant steps to obtain a faithful model are lined out. This procedure yields a partial game graph with 6764 nodes and approx. 321,022 edges --- some uncertainty included. Current pathfinding techniques are discussed and assessed regarding their applicability to the presented speedrun routing problem. The resulting graph model and algorithmic approaches present a good reference to identify the most promising points of improvement. Challenges, flaws and possible solutions to still standing problems are discussed and assumptions from prior works are assessed. Finally, further tracks of scholarly and community work in this area are suggested and possible extensions to the approach are lined out.
It is shown that speedrun routing is not a trivial shortest path problem that can be solved with conventional methods. Furthermore, it is made clear that different games can have vastly differing routing circumstances. Assumptions of other works have been assessed using a working example and many interesting challenges and fields of further study and research in the field of speedrunning have been identified. Some probabilistic pathfinding methods and current works on AI agents for games pose interesting approaches which can be extended on by utilizing the findings of the presented work. Specialized modeling and optimization techniques have to be employed in order to have a positive effect on the speedrunning community.
The 15th Annual Meeting of the Sponsoring Group Reinsurance [Förderkreis Rückversicherung] was held 24 June 2022. As a result of the COVID-19 pandemic, the event was held in online format again this year. Some 110 representatives of the (re)insurance companies involved in the Sponsoring Group took part in the meeting, along with guests. Offered for the eighth time as part of the Annual Meeting, the Researchers’ Corner gave the seven academic researchers at the Cologne Research Centre for Reinsurance an opportunity to deliver a presentation on the research project in which each is involved in 2022.
Over the course of three sessions, the most important results of the scientific studies by the Cologne Research Centre for Reinsurance were presented and discussed. The heterogeneity of the topics presented reflects the dovetailing of the Cologne Research Centre with reinsurance practice.
Session 1
a) Erik Winkler (LL. B.): Insurance Capital Standard (ICS)
b) Lihong Wang (M.Sc., FCII): Developments in Chinese Online Insurance 2022
c) Jörg Dirks (M.Sc., FCII): Retrocession within an ESG-compliant business orientation
Session 2
a) Robert Joniec (M.Sc., FCII, cand. PhD): Classic reinsurance placements and auctions – We know that we know nothing
b) Wolfgang Koch (M.Sc., FCII): Accounting for climate-change scenarios in the ORSA
Session 3
a) Frank Cremer (M.Sc., FCII, cand. PhD): Limits of (re)insurance cover – An analysis of exclusions of cyber-conditions
b) Fabian Lassen (M.Sc., FCII): ESG criteria in reinsurer underwriting
With the publication series, ‘Proceedings of the Researchers’ Corner’, the Cologne Research Centre for Reinsurance meets the desire for publication of the research results of our researchers along with the related discussions. The titles are reproduced in keeping with the above agenda of the Researchers’ Corner for the 15th Annual Meeting of the Sponsoring Group Reinsurance.
We would like to express our deep gratitude to the sponsors with whose assistance the activities of the Cologne Research Centre for Reinsurance, and the Annual Meeting of the Sponsoring Group Reinsurance in particular, are possible.
This project was done in collaboration with CERN and is part of the detector control system of the ATLAS experiment. The primary goal foresaw the development and testing of the FPGA card for the MOPS-HUB crate with the focus on radiation tolerance. This was accomplished with the approach of designing two different PCBs. The first PCB was created as a fast prototype with the use of a commercial SOM-board. This was also beneficial for confirming that the chosen FPGA is suitable for the MOPS-HUB application. After the successful assembly and test, a second, more complex and foremost radiation tolerant PCB was designed. This was achieved by solely using components of the CERN radiation database.
The second part of this thesis focuses on increasing the distance of TMR registers with a Python script. A method was created for extracting and later parsing a design’s placement
information from Vivado. Furthermore, were system designed and implemented to recognize TMR cells, to find and validate free cells and to finally create a new placement for import into Vivado. These algorithms were tested with a multitude of configurations and the quality, based on the maximum possible frequency of a design, determined.
Effects on the combustion properties of wheat straw after different thermobiological pretreatments
(2022)
Wheat straw could be used for pellet production and therefore as solid fuel. However, it presents challenges due to its inferior combustion properties such as high ash content, low gross calorific value (GCV), and low ash melting temperature.
To evaluate its combustion properties and based on recent work that improved methane production, wheat straw was subjected to thermobiological pretreatments. Nine pretreated samples based on wheat straw and nine pretreated samples based on compost-wheat straw mixture were produced. In addition, due to the ability to remove minerals and decrease the ash content, a washing process with water as a solvent was used. Ash content, net calorific value (NCV) and ash melting temperatures were evaluated.
For the pretreated wheat straw (SW) samples, a 5,8% reduction in ash content was obtained due to the pretreatments when compared to untreated wheat straw. A 55% decrease in ash content was obtained when comparing the same materials before and after the washing process. No statistically significant changes in GCV were found. As for the ash melting temperatures, due to the incubation pretreatment, an average increase in the shrinkage starting temperature (SST) of 4,4% was obtained for anaerobic conditions and a decrease of 2,5% for aerobic conditions, compared to the same material without heat treatment. In addition, an increase in all ash melting temperatures was observed because of the washing process. It was possible to obtain a pellet complying with standard ISO 17225-6 that can be used in medium or large burners and significantly reduces the effort during combustion.
For samples pretreated with a homogeneous compost-wheat straw (SKW) mixture, an average ash content decrease of 27% was obtained after using autoclave pretreatment at 140°C, compared to the same material without thermal pretreatment. The biggest decrease was due to the washing process, reducing the ash content on average by 43% when comparing the same materials before and after washing. GCV were 13% lower than samples pretreated with wheat straw, due to the low calorific value and high ash content of the compost. During ash melting temperature tests, an average 60% increase in SST was observed compared to pretreated SW ashes due to the high melting temperature of compost. Results are considered satisfactory since pellets based on this mixture would not cause ash sintering or slagging. However, counter effects were observed as the addition of compost increased the ash content and decreased the GCV, not complying with ISO 17225-6 for non-woody pellets. To achieve a pellet based on a compost-wheat straw mixture that complies with the standards, it is recommended for future research to control the percentage of compost added to the mixture.
This market research paper has been prepared under the supervision of Prof. Dr. Agnieszka Gehringer of TH Köln and Prof. Dr. Carol Scovotti of University of Wisconsin-Whitewater in the course of the inter-university cross-border collaboration student research project “Export Opportunity Surveys (EOS)”. This study explores organic oranges export opportunities to the German and US markets.
Circular economy (CE) has received considerable interest in recent years as a strategy to resolve some of our modern urban resource challenges, and circular city models often incorporate systems of urban agriculture in their design. Much work has analyzed the benefits of urban agriculture for creating a resilient food system and as a strategy for supporting urban green space and social cohesion, however, the contributions from business models that operate within urban agriculture have not been thoroughly studied. Many urban agriculture businesses often claim high levels of resource recycling and material circularity, though whether a resource efficiency throughout the entire product lifetime (including energy and material footprint for the cultivation equipment) in comparison to current industrial strategies is truly feasible or even possible is still to be debated. This thesis builds upon work that incorporates social dimensions of CE definitions and begins to research whether the potential resource efficiency contradiction can be justified as to make urban agriculture a valid approach for circular city design. This study examined an urban mushroom farm that implements a circular business model. A qualitative summary of the business operations and resource flows were unpacked and sorted into 24 socio-economic contributions based on their interpreted relevance. The interpreted data shows that an urban agriculture business model can contribute to the building blocks of a CE through economic, ecological, social, and spatial contributions. While these contributions can contribute positively to the operationalization of CE, potential trade-offs regarding resource efficiency, use of urban space, and investment priorities need to be considered and addressed to avoid a possible watering down or greenwashing of the CE concept.
The management of the liquid fraction of digestate produced from the anaerobic digestion of biodegradable municipal solid waste is a difficult affair, as its land application is limited due to high ammonium concentrations and the municipal waste that water treatment plants struggle to treat due to high pollutant loads. The amount of leachate and the pollutant load in the leachate produced by landfills usually decreases with the time, which increases the capacity of landfill leachate treatment plants (LLTPs) to treat additional wastewater. In order to solve the above two challenges, the co-treatment of landfill leachate and the liquid fraction of anaerobic digestate in an industrial-scale LLTP was investigated along with the long-term impacts of the liquid fraction of anaerobic digestate on biocoenosis and its impact on LLTP operational expenses. The co-treatment of landfill leachate and liquid fraction of anaerobic digestate was compared to conventional leachate treatment in an industrial-scale LLTP, which included the use of two parallel lanes (Lane-1 and Lane-2). The average nitrogen removal efficiencies in Lane-1 (co-treatment) were 93.4%, 95%, and 92%, respectively, for C/N ratios of 8.7, 8.9, and 9.4. The average nitrogen removal efficiency in Lane-2 (conventional landfill leachate treatment), meanwhile, was 88%, with a C/N ratio of 6.5. The LLTP’s average chemical oxygen demand (COD) removal efficiencies were 63.5%, 81%, and 78% during phases one, two, and three, respectively. As the volume ratios of the liquid fraction of anaerobic digestate increased, selective oxygen uptake rate experiments demonstrated the dominance of heterotrophic bacteria over ammonium and nitrite-oxidising organisms. The inclusion of the liquid fraction of anaerobic digestate during co-treatment did not cause a significant increase in operational resources, i.e., oxygen, the external carbon source, activated carbon, and energy.
A bifacial Photovoltaic (PV) simulation model is created by combining the optical View Factor matrix with electrical output simulation in python to analyse the energy density of bifacial systems. A discretization of the rear side of the bifacial modules allows a further investigation of mismatching and losses due to inhomogeneous radiation distribution. The model is validated, showing a deviation of -1.25 % to previous simulation models and giving hourly resolvedoutput data with a higher accuracy than existing software for bifacial PV systems.
In this study the link between renewable energies and employment in Senegal is analyzed.
The Sustainable Livelihood Approach is used to understand the investigated situation in a holistic view. To successfully implement renewable energies in Senegal and to have a significant impact on the employment market, the governmental framework and the technical education has to improve, to match the needs of the labor market.
Rural communities do not have all the assets to lift themselves out of poverty and disadvantages by the usage of renewable energy. Solar irrigation, off-grid systems and solar devices impact the level of education and the labor force in rural areas in Senegal.
Moreover, access to a reliable energy source improves people’s livelihood in terms
of health, education, income and employment.
The resulting employment effect of adding 20 MW with the solar power plant Senergy 2 can be estimated with 28.686 created jobs (0,54 % of total employment).
Upcoming power projects offer employment opportunities for graduates of the master study renewable energies. Furthermore, the demand of specialized engineers and
technicians in the distribution and project planning sector will rise.