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Maximum Likelihood Uncertainty Estimation: Robustness to Outliers
Get PDFWe benchmark the robustness of maximum likelihood based uncertainty estimation methods to outliers in training data for regression tasks. Outliers or noisy labels in training data results in degraded performances as well as incorrect estimation of uncertainty. We propose the use of a heavy-tailed distribution (Laplace distribution) to improve the robustness to outliers. This property is evaluated using standard regression benchmarks and on a high-dimensional regression task of monocular depth estimation, both containing outliers. In particular, heavy-tailed distribution based maximum likelihood provides better uncertainty estimates, better separation in uncertainty for out-of-distribution data, as well as better detection of adversarial attacks in the presence of outliers
Recovery Across Different Temporal Settings: How Lunchtime Activities Influence Evening Activities
No full textRecovery from work stress during workday breaks, free evenings, weekends, and vacations is known to benefit employee health and well-being. However, how recovery at different temporal settings is interconnected is not well understood. We hypothesized that on days when employees engage in recovery-enhancing lunchtime activities, they will experience higher resources when leaving home from work (i.e., low fatigue and high positive affect) and consequently spend more time on recovery-enhancing activities in the evening, thus creating a positive recovery cycle. In this study, 97 employees were randomized into lunchtime park walk and relaxation groups. As evening activities, we measured time spent on physical exercise, physical activity in natural surroundings, and social activities. Afternoon resources and time spent on evening activities were assessed twice a week before, during, and after the intervention, for five weeks. Our results based on multilevel analyses showed that on days when employees completed the lunchtime park walk, they spent more time on evening physical exercise and physical activity in natural surroundings compared to days when the lunch break was spent as usual. However, neither lunchtime relaxation exercises nor afternoon resources were associated with any of the evening activities. Our findings suggest that other factors than afternoon resources are more important in determining how much time employees spend on various evening activities. Fifteen-minute lunchtime park walks inspired employees to engage in similar healthbenefitting activities during their free time
Contingency analysis for gas transport networks with hydrogen injection
No full textNovel methods for contingency analysis of gas transport networks are presented. They are motivated by the transition of our energy system where hydrogen plays a growing role. The novel methods are based on a specific method for topological reduction and so-called supernodes. Stationary Euler equations with advanced compressor thermodynamics and a gas law allowing for gas compositions with up to 100% hydrogen are used. Several measures and plots support an intuitive comparison and analysis of the results. In particular, it is shown that the newly developed methods can estimate locations and magnitudes of additional capacities (injection, buffering, storage etc.) with a reasonable performance for networks of relevant composition and size
Critical success factors for working in home office–an empirical analysis from the perspective of employers and employees
Get PDFVor dem Hintergrund der Covid-19-Pandemie hat sich das Home-Office in Deutschland seit dem Jahr 2020 weit verbreitet und wird seitdem bei vielen Arbeitgebern als neue Arbeitsmethode genutzt. Der Einsatz von Home-Office kann verschiedene positive als auch negative Effekte auf die Beschäftigten und den Arbeitgeber sowie die Gesellschaft allgemein haben. Damit von möglichst vielen positiven Effekten profitiert werden kann, ist ein gutes Home-Office Konzept erforderlich. Welche Anforderungen an ein solches Konzept bestehen und welche Voraussetzungen grundlegend mit der Nutzung von Home-Office verbunden sind, wird in dem Beitrag aufgezeigt. Dabei werden von technischen bis hin zu sozialen Aspekten Anforderungen verschiedener Arten berücksichtigt, welche durch eine durch den Autor durchgeführte Studie gebildet worden sind. Im Fokus dieses Beitrages sollen die kritischen Erfolgsfaktoren für das ideale Arbeiten im Home-Office stehen, also die Anforderungen, welche ausschlaggebend für die erfolgreiche Umsetzung eines Home-Office Konzeptes sind und Einfluss auf die wahrgenommenen Effekte des Home-Office haben. Die im Beitrag aufgeführte Studie des Autors wurde im Rahmen der Abschlussarbeit von Herrn Jeske durchgeführt, auf welcher der Beitrag basiert.Against the background of the Covid-19 pandemic, the home office has become widespread in Germany since 2020 and has since been used as a new working method by many employers. The use of home offices can have various positive and negative effects on employees and employers as well as society in general. In order to benefit from as many positive effects as possible, a good home office concept is required. The article shows which requirements exist for such a concept and which prerequisites are fundamentally associated with the use of home offices. From technical to social aspects, requirements of various types are considered, which have been formed by a study carried out by the author. The focus of this article should be the critical success factors for ideal work in the home office, i.e. the requirements that are decisive for the successful implementation of a home office concept and have an influence on the perceived effects of the home office. The author’s study listed in the article was carried out as part of Mr. Jeske’s thesis, on which the article is based
Experiment verification test of the Artemis I ‘Deep Space Radiation Genomics’ experiment
No full textWhen the Artemis missions launch, NASA's Orion spacecraft (and crew as of the Artemis II mission) will be exposed to the deep space radiation environment beyond the protection of Earth's magnetosphere. Hence, it is essential to characterize the effects of space radiation, microgravity, and the combination thereof on cells and organisms, i.e., to quantify any correlations between the deep space radiation environment, genetic variation, and induced genetic changes in cells. To address this, the Artemis I mission will include the Peristaltic Laboratory for Automated Science with Multigenerations (PLASM) hardware containing the Deep Space Radiation Genomics (DSRG) experiment. The scientific aims of DSRG are (i) to identify the metabolic and genomic pathways in yeast affected by microgravity, space radiation, and their combination, and (ii) to differentiate between gravity and radiation exposure on single-gene deletion/overexpressing strains' ability to thrive in the spaceflight environment. Yeast is used as a model system because 70% of its essential genes have a human homolog, and over half of these homologs can functionally replace their human counterpart. As part of the experiment preparation towards spaceflight, an Experiment Verification Test (EVT) was performed at the Kennedy Space Center to verify that the experiment design, hardware, and approach to automated operations will enable achieving the scientific aims. For the EVT, fluidic systems were assembled, sterilized, loaded, and acceptance-tested, and subsequently integrated with the engineering parts to produce a flight-like PLASM unit. Each fluidic system consisted of (i) a Media Bag, (ii) four Culture Bags loaded with Saccharomyces cerevisiae (two with deletion series and the remaining two with overexpression series), and (iii) tubing and check valves. The EVT PLASM unit was put under a temperature profile replicating the anticipated different phases of flight, including handover to launch, spaceflight, and splashdown to handover back to the science team, for a 58-day period. At EVT completion, the rate of activation, cellular growth, RNA integrity, and sample contamination were interrogated. All of the experiment's success criteria were satisfied, encouraging our efforts to perform this investigation on Artemis I. This manuscript thus describes the process of spaceflight experiment design maturation with a focus on the EVT, its results, DSRG's preparation for its planned launch on Artemis I in 2022, and how the PLASM hardware can enable other scientific goals on future Artemis missions and/or the Lunar Orbital Platform – Gateway
Principal Component Analysis in Gas Transport Simulation
No full textIn this paper, an analysis of the error ellipsoid in the space of solutions of stationary gas transport problems is carried out. For this purpose, a Principal Component Analysis of the solution set has been performed. The presence of unstable directions is shown associated with the marginal fulfillment of the resistivity conditions for the equations of compressors and other control elements in gas networks. Practically, the instabilities occur when multiple compressors or regulators try to control pressures or flows in the same part of the network. Such problems can occur, in particular, when the compressors or regulators reach their working limits. Possible ways of resolving instabilities are considered
Impact of Aerosols on Photovoltaic Energy Production Using a Spectrally Resolved Model Chain: Case Study of Southern West Africa
No full textBased on an analysis of the aerosol optical properties for Cotonou, Benin from the DACCIWA measurement campaign, we investigate the impact of aerosols on PV power for polycrystalline silicon and amorphous silicon technology using a spectrally resolved model chain. The model considers both spectral effects on global irradiance due to different aerosol properties as well as the spectral response of different PV technologies. The results show that aerosol emissions due to the biomass outbreak lead to solar flux losses of up to 55%, which correspond to a reduction in photovoltaic power of up to 81% for the polycrystalline cell and 78% for the amorphous cell. Comparing the effects of aerosols on the photovoltaic power between the two technologies, we find that during the morning and evening hours, when there is more diffuse irradiance, the amorphous cell suffers a greater reduction in power (36%) than the polycrystalline cell (27%). Conversely, in the middle of the day, we observe a greater PV power reduction of 12% for the polycrystalline cell compared to that for the amorphous cell (8%)
Being an accountant, cook, entertainer and teacher—all at the same time: Changes in employees' work and work‐related well‐being during the coronavirus (COVID‐19) pandemic
Get PDFIn March 2020, the world was hit by the coronavirus disease (COVID‐19) pandemic which led to all‐embracing measures to contain its spread. Most employees were forced to work from home and take care of their children because schools and daycares were closed. We present data from a research project in a large multinational organisation in the Netherlands with monthly quantitative measurements from January to May 2020 (N = 253–516), enriched with qualitative data from participants' comments before and after telework had started. Growth curve modelling showed major changes in employees' work‐related well‐being reflected in decreasing work engagement and increasing job satisfaction. For work‐non‐work balance, workload and autonomy, cubic trends over time were found, reflecting initial declines during crisis onset (March/April) and recovery in May. Participants' additional remarks exemplify that employees struggled with fulfilling different roles simultaneously, developing new routines and managing boundaries between life domains. Moderation analyses demonstrated that demographic variables shaped time trends. The diverging trends in well‐being indicators raise intriguing questions and show that close monitoring and fine‐grained analyses are needed to arrive at a better understanding of the impact of the crisis across time and among different groups of employees
Suitability of Voltage Sensors for the Measurement of Switching Voltage Waveforms in Power Semiconductors
No full textThis paper investigates the effect of voltage sensors on the measurement of transient voltages for power semiconductors in a Double Pulse Test (DPT) environment.We adapt previously published models that were developed for current sensors and apply them to voltage sensors to evaluate their suitability for DPT applications. Similarities and differences between transient current and voltage sensors are investigated and the resulting methodology is applied to commercially available and experimental voltage sensors. Finally, a selection aid for given measurement tasks is derived that focuses on the measurement of fast-switching power semiconductors