874 research outputs found
Feature- and Structure-Preserving Network Reduction for Large-Scale Transmission Grids
Many countries are currently challenged with the extensive integration of
renewable energy sources, which necessitates vast capacity expansion measures.
These measures in turn require comprehensive power flow studies, which are
often computationally highly demanding. In this work a reduction strategy for
large-scale grid models is introduced which not only reduces the model
complexity but also preserves the structure and designated grid features. The
objective is to ensure that areas crucial to the behavior and the relation of
all elements to their physical counterparts remain unchanged. This is
accomplished through a specifically designed reduction method for suitable
areas identified through topological, electrical and market-based approaches
for which we provide an open-source implementation. We show that the proposed
strategy adapts to various models and accomplishes a strong reduction of buses
and branches while retaining a low dispatch and branch flow deviation.
Furthermore, the accuracy of the reduction generalizes well to other scenarios.Comment: 13th IEEE PowerTech Conference 201
Thin concrete overlays wit carbon reinforcement on deteriorated concrete pavements
In many countries, concrete pavements are normally built as Jointed Plain Concrete Pavements. Due to a lack of alternatives, repairing deteriorated concrete pavements usually requires the replacement of the complete pavement structure and maintaining the joints, which is labour- and resource-intensive. To increase the durability of repairs and to save resources concrete overlays with carbon reinforcement are developed. By the application of non-corrosive carbon-textile reinforcement cracks might be distributed so fine, that such an overlay can be executed jointless, unlike in previous repair methods. For a durable repair the bond behaviour between the retained concrete and the overlay as well as between the overlay-concrete and the textile reinforcement have to be considered. In this paper, the basic principles and feasibility of such a repair method are examined. On the one hand, the decisive influencing variables and parameters such as bond behaviour and cracking behaviour within the overlay are pointed out and discussed. On the other hand, the performed special lab tests will be presented. These tests include cyclic loadings on large-scale beams with integrated overlays of such types, evaluating the bond behaviour and the durability after a few millions of load cycles. Furthermore, the crack formation in the overlay is determined by means of tensile and flexural tensile strength tests
Semesterbegleitende Unterstützung von Tutoren zum feed-backorientierten Korrigieren von Übungsaufgaben in einer Erstsemestervorlesung
HICU PIE results of neutron-irradiated lithium metatitanate pebbles
Lithium metatitanate (Li2TiO3) pebbles were irradiated with neutrons within the HICU (High neutron fluence Irradiation of pebble staCks for fUsion) experiment to investigate their material properties and tritium release behaviour in a post-irradiation examination (PIE). The irradiation temperature is the most significant influence on the material. Besides a higher irradiation temperature, a higher initial Li–6 content tends to lead to an increased tritium generation resulting in the formation of the secondary lithium depleted phase Li4Ti5O12. A pre-compaction of the pebble bed does not have an apparent influence on the material properties. Tritium is released as semi-tritiated water and semi-tritiated hydrogen (HTO and HT) and its release is enhanced at elevated irradiation temperatures
Healthcare Effectiveness as a Wellbeing Factor. Workforce
Wellbeing of citizens is a multifactorial and a multi-aspect process. One of the key aspects is health. Despite the fact that health depends on the healthcare system on 15-20% only, it is vital to improve its efficiency. Authors highlight that, on the one hand, healthcare as social-economical system must be targeted on citizens’ health improvement, and on the other hand, it must obey economic processes. Modernization and reforming of healthcare system demand effectiveness increase of all types of resources in this context; but authors imply that the key ones are the workforce resources. A conducted monitoring of Russian Federation citizens’ health on several diseases as well as an evaluation of Russian Federation workforce resources usage through 2003-2013 (level of an institution (federal, regional, municipal), provision, staff ratio (physicians and nurses), its correspondence to staff schedule, qualifications level, etc. were used as the criteria) and also a comparison of federal districts healthcare system effectiveness (using Minmax method) did not show synonymous dynamics.Increase in staff usage effectiveness is a factor of healthcare system effectiveness raise, which is a factor of citizens wellbeing improving
Entwicklung eines Anforderungsprofils für Kontrolleure im Rahmen des Kontrollsystems nach der EU-Verordnung 2092/91
Ziel der Studie ist es, das Anforderungsprofil für Kontrolleure auf der Grundlage der EU-Öko-Verordnung 2092/91 für die unterschiedlichen Kontrollbereiche zu ermitteln.
Grundlage dafür bilden die Analyse der Tätigkeiten von Kontrolleuren aufgegliedert nach Branchen in die verschiedenen Kontrollbereiche Landwirtschaft, Verarbeitung und Import aus Drittländern. Ergänzend wurde erfasst, welche Anforderungen in anderen Kontroll- und Qualitätssicherungsnormen und -verordnungen an das Kontroll- bzw. Auditpersonal gestellt werden.
Ableitend von diesen Analysen wurde das Anforderungsprofil für die drei Kontrollbereiche erstellt. Das Anforderungsprofil gliedert sich in vier Teile: die persönliche Qualifikation (in Anlehnung an ISO 10011), die Basisqualifikation (mündliche und schriftliche Kommunikation, Kalkulation, Berufserfahrung), die fachliche Qualifikation, die sich je nach Kontrollbereich unterscheidet sowie die Kenntnisse der gesetzlichen Regelungen. Für jeden Baustein im Anforderungsprofil wurde abgeleitet, mit welcher Berufsausbildung, Trainingsmaßnahme o.ä. diese Qualifikation erreicht und wie sie nachgewiesen werden kann.
In diesem Zusammenhang wurde auch das in Deutschland übliche Zulassungsverfahren für Kontrollpersonal diskutiert. Die Verordnung (EWG) 2092/91 sowie der ergänzend geltenden EN 45011 enthält keine Vorgaben, welche die Zulassung von Kontrolleuren durch Aufsichtsbehörden vor dem Einsatz erforderlich machen. Es muss allerdings im Rahmen der Überwachung der Kontrollstellen überprüft werden, ob die Kontrollstellen über sachgerechte Personalkriterien, ein angemessenes dokumentiertes Verfahren für die Auswahl des Personals sowie individuelle Leistungsbeurteilungen verfügen und das Personal angemessen aus- und fortbilden.
Eine Umfrage bei den Kontrollstellen im deutschsprachigen Raum erfasste die derzeitigen Aus- und Fortbildungsmaßnahmen für Kontrollpersonal. Auf Grundlage der Auswertung der Tätigkeitsanalysen und der Rückmeldungen der Kontrollstellen wurde festgestellt, dass Bedarf an einem kontrollstellenüber-greifenden Fortbildungsangebot besteht, das sich vor allem auf die Spezialbereiche im Kontrollsystem konzentriert (z.B. Umgang mit schwierigen Kontrollsituationen, Aktuelle Änderungen der VO 2092/91, Hofverarbeitung, Rückstandsanalytik und Probenahmeverfahren, Importkontrolle)
The Role of Culture and Personality in the Leadership Process in Virtual Teams
Leadership is a key challenge of virtual teams. A particular leadership style, namely inspirational leadership, which is a sub-category of transformational leadership, has been found to be especially suited for the study of highly diverse teams. Virtual team leaders increasingly have to manage global virtual teams that contain members from different cultural backgrounds and value orientations. This study answers a call of incorporating the role of individual-level attributes and dispositions as moderators of inspirational leadership effects, considering cultural and individual values of followers in a virtual setting. Results reveal the importance of inspirational leadership influencing attitudinal outcomes (trust in leadership and cohesion). Furthermore, the effect of leadership is shown to be dependent on cultural as well as personal values of followers indicating the need to consider individual factors in the process of managing virtual teams
Conflict, Value Diversity, and Performance in Virtual Teams
While most studies investigating culture in the context of conflict in teams have been using culture dimensions such as collectivism this study centers on another measurement of culture, namely individual values. In this investigation we examined how individual value diversity influences the relationship between team conflict and performance in virtual teams. Assessing two types of conflict, namely task and process conflict, the results revealed that task conflict had no unique effect beyond the impact of process conflict. Contrary to previous findings relating to group culture, this study found that value diversity has no influence on the relationship between conflict and performance in virtual teams. While individuals come to groups with their own values, they may be less powerful predictors of their behavior in groups where there are strong prevailing group values and norms to act a certain way
Neurocognitive Deficits in First-Episode and Chronic Psychotic Disorders: A Systematic Review from 2009 to 2022
Cognitive impairment in patients suffering from schizophrenia spectrum disorders has been discussed as a strong predictor for multiple disease outcome variables, such as response to psychotherapy, stable relationships, employment, and longevity. However, the consistency and severity of cognitive deficits across multiple domains in individuals with first-episode and chronic psychotic disorders is still undetermined. We provide a comprehensive overview of primary research from the years 2009 to 2022. Based on a Cochrane risk assessment, a systematic synthesis of 51 out of 3669 original studies was performed. Impairment of cognitive functioning in patients diagnosed with first-episode psychotic disorders compared with healthy controls was predicted to occur in all assessed cognitive domains. Few overall changes were predicted for chronically affected patients relative to those in the first-episode stage, in line with previous longitudinal studies. Our research outcomes support the hypothesis of a global decrease in cognitive functioning in patients diagnosed with psychotic disorders, i.e., the occurrence of cognitive deficits in multiple cognitive domains including executive functioning, memory, working memory, psychomotor speed, and attention. Only mild increases in the frequency of cognitive impairment across studies were observed at the chronically affected stage relative to the first-episode stage. Our results confirm and extend the outcomes from prior reviews and meta-analyses. Recommendations for psychotherapeutic interventions are provided, considering the broad cognitive impairment already observed at the stage of the first episode. Based on the risk of bias assessment, we also make specific suggestions concerning the quality of future original studies
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