opus htw (Hochschule für Technik und Wirtschaft Berlin)
Not a member yet
1647 research outputs found
Sort by
Inländische Geschäftsanschrift vom Prüfungsrecht des Registergerichts umfasst
No full textBesprechung KG Berlin 22. Zivilsenat, Beschluss vom 14.01.2021 - 22 W 1053/20
Highly Accurate, But Still Discriminatory
No full textThe study aims to identify whether algorithmic decision making leads to unfair (i.e., unequal) treatment of certain protected groups in the recruitment context. Firms increasingly implement algorithmic decision making to save costs and increase efficiency. Moreover, algorithmic decision making is considered to be fairer than human decisions due to social prejudices. Recent publications, however, imply that the fairness of algorithmic decision making is not necessarily given. Therefore, to investigate this further, highly accurate algorithms were used to analyze a pre-existing data set of 10,000 video clips of individuals in self-presentation settings. The analysis shows that the under-representation concerning gender and ethnicity in the training data set leads to an unpredictable overestimation and/or underestimation of the likelihood of inviting representatives of these groups to a job interview. Furthermore, algorithms replicate the existing inequalities in the data set. Firms have to be careful when implementing algorithmic video analysis during recruitment as biases occur if the underlying training data set is unbalanced
Stability Assessment of p-i-n Perovskite Photovoltaic Mini-Modules Utilizing Different Top Metal Electrodes
No full textLong-term stability is one of the major challenges for p-i-n type perovskite solar modules (PSMs). Here, we demonstrate the fabrication of fully laser-patterned series interconnected p-i-n perovskite mini-modules, in which either single Cu or Ag layers are compared with Cu/Au metalbilayer top electrodes. According to the scanning electron microscopy measurements, we found that Cu or Ag top electrodes often exhibit flaking of the metal upon P3 (top contact removal) laser patterning. For Cu/Au bilayer top electrodes, metal flaking may cause intermittent short-circuits between interconnected sub-cells during operation, resulting in fluctuations in the maximum power point (MPP). Here, we demonstrate Cu/Au metal-bilayer-based PSMs with an efficiency of 18.9% on an active area of 2.2 cm2 under continuous 1-sun illumination. This work highlights the importance of optimizing the top-contact composition to tackle the operational stability of mini-modules, and could help to improve the feasibility of large-area module deployment for the commercialization of perovskite photovoltaics
Requirements Elicitation for an Assistance System for Complexity Management in Product Development of SMEs during COVID-19: A Case Study
No full textTechnological progress, upcoming cyber-physical systems, and limited resources confront small and medium-sized enterprises (SMEs) with the challenge of complexity management in product development projects spanning over the entire product lifecycle. SMEs require a solution for documenting and analyzing the functional relationships between multiple domains such as products, software, and processes. The German research project FuPEP “Funktionsorientiertes Komplexitätsmanagement in allen Phasen der Produktentstehung” aims to address this issue by developing an assistance system that supports product developers by visualizing functional relationships. This paper presents the methodology and results of the assistance system’s requirements elicitation with two SMEs. Conducting the elicitation during a global pandemic, we discuss its application using specific techniques in light of COVID-19. We model problems and their effects regarding complexity management in product development in a system dynamics model. The most important requirements and use cases elicited are presented, and the requirements elicitation methodology and results are discussed. Additionally, we present a multilayer software architecture design of the assistance system. Our case study suggests a relationship between fear of a missing project focus among project participants and the restriction of requirements elicitation techniques to those possible via web conferencing tools
Analyse der Impfbereitschaft der Deutschen anhand von Beiträgen auf Twitter
No full textDas Robert Koch-Institut (RKI) hält in Anbetracht der COVID-19-Pandemie und der auftretenden Delta-Variante eine hohe Impfquote für nötig, um COVID-19 in den kommenden Monaten zu kontrollieren. Um die Impfquote zu approximieren, führt das Institut die COVIMO-Studie durch, welche die Impfbereitschaft mittels einer Telefonbefragung von Bürgern festhält. Durch die Einschränkung auf Telefongespräche bildet es nicht die Impfbereitschaft der gesamten deutschen Bevölkerung ab. Damit ein weiterer Teil der Bevölkerung abgedeckt wird, ist es angebracht, Beiträge auf sozialen Medien wie Twitter dahingehend auszuwerten.
Das Ziel in der vorliegenden Arbeit ist es, die Impfbereitschaft der Deutschen aus Meinungstexten auf Twitter zu bestimmen. Um die Zielsetzung zu erreichen, wurden Inhalte auf Twitter gesammelt, die sich auf die Impfthematik beziehen. Daraufhin sind die Konversationen rekonstruiert und anschließend auf ihre Ernsthaftigkeit untersucht worden. Die scherzhaften Konversationen wurden auf spezifische Merkmale untersucht, um eine Tendenz zu den Merkmalen: Längste Diskussionskette und Anzahl der Antworten auf Tweets aufzuweisen. Schließlich wurden für eine qualitative Aussage nur ernsthafte Tweets berücksichtigt.
Die Ergebnisse der Untersuchung zeigen, dass scherzhafte Inhalte auf Twitter vermehrt in Konversationen mit längeren Diskussionsketten und Antworten auf einzelne Tweets vorhanden sind. Die Untersuchung der Impfbereitschaft ergibt eine überwiegende Tendenz der deutschen Nutzer, sich impfen zu lassen, während eine Minderheit eher abgeneigt ist
Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment — A Summary
No full textStatic immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60°C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60°C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied
27.9% Efficient Monolithic Perovskite/Silicon Tandem Solar Cells on Industry Compatible Bottom Cells
No full textMonolithic perovskite/silicon tandem solar cells recently surpass the efficiency of silicon single‐junction solar cells. Most tandem cells utilize >250 μm thick, planarized float‐zone (FZ) silicon, which is not compatible with commercial production using <200 μm thick Czochralski (CZ) silicon. The perovskite/silicon tandem cells based on industrially relevant 100 μm thick CZ‐silicon without mechanical planarization are demonstrated. The best power conversion efficiency (PCE) of 27.9% is only marginally below the 28.2% reference value obtained on the commonly used front‐side polished FZ‐Si, which are about three times thicker. With both wafer types showing the same median PCE of 27.8%, the thin CZ‐Si‐based devices are preferred for economic reasons. To investigate perspectives for improved current matching and, therefore, further efficiency improvement, optical simulations with planar and textured silicon have been conducted: the perovskite's bandgap needs to be increased by ≈0.02 eV when reducing the silicon thickness from 280 to 100 μm. The need for bandgap enlargement has a strong impact on future tandem developments ensuring photostable compositions with lossless interfaces at bandgaps around or above 1.7 eV
Grid Forming Stator Flux Control of Doubly-Fed Induction Generator
No full textThe doubly fed induction generator is widely used in wind power applications. For stand-alone operation of this machine, the control of the stator flux with fixed voltage and frequency has been proposed. This paper extends the stator flux control of the doubly fed induction machine by droop mechanisms, which vary the setpoint of flux magnitude and frequency depending on active and reactive power. This gives the doubly fed induction generator system unknown grid supporting and grid forming performance. The validation of the proposed control scheme has been conducted on a 10kVA testbed system. The closed-loop behavior of the system has been proven to enable grid-tied and islanded operation with the same control structure. The system response to load changes and islanding events show no disruptive transients in both conditions
Verjährungshemmung des Abfindungsanspruchs während der Beschlussmängelklage gegen den Ausschluss als Gesellschafter
No full textBesprechung BGH 2. Zivilsenat, Urteil vom 18.05.2021 - II ZR 41/20.
Leitsatz:
Wendet sich der durch Beschluss der Gesellschafter aus wichtigem Grund ausgeschlossene Gesellschafter im Klageweg gegen die Wirksamkeit seines Ausschlusses, ist es ihm im Regelfall nicht zuzumuten, seinen Abfindungsanspruch vor der rechtskräftigen Entscheidung über die Wirksamkeit des Ausschlusses gerichtlich geltend zu machen.
Orientierungssatz zur Anmerkung: Die Klage gegen einen nicht offensichtlich wirksamen Ausschluss hemmt den Beginn der Verjährung des Abfindungsanspruchs
Machine intelligence today: applications, methodology, and technology
No full textMachine intelligence, a.k.a. artificial intelligence (AI) is one of the most prominent and relevant technologies today. It is in everyday use in the form of AI applications and has a strong impact on society. This article presents selected results of the 2020 Dagstuhl workshop on applied machine intelligence. Selected AI applications in various domains, namely culture, education, and industrial manufacturing are presented. Current trends, best practices, and recommendations regarding AI methodology and technology are explained. The focus is on ontologies (knowledge-based AI) and machine learning