Search results for "multilevel"
showing 10 items of 338 documents
Selective harmonic mitigation with asymmetrical staircase voltage waveform for a three-phase five-level Cascaded H-Bridge Inverter
2020
Selective harmonics elimination or mitigation strategies are used in all applications where it is necessary to rise the efficiency and reliability of the overall system. This paper presents a simple approach to reduce the low order harmonics amplitude of an asymmetrical staircase voltage waveform for a five-level, three-phase Cascaded H-Bridge Inverter without solving non-linear equations. Through this simple approach, polynomial equations to evaluate the control angels in real-time operations have been found. The effectiveness of the harmonic mitigation method has been tested through the simulation analysis in MatLab/PLECS environment.
A Novel Computational Approach for Harmonic Mitigation in PV Systems with Single-Phase Five-Level CHBMI
2018
In this paper, a novel approach to low order harmonic mitigation in fundamental switching frequency modulation is proposed for high power photovoltaic (PV) applications, without trying to solve the cumbersome non-linear transcendental equations. The proposed method allows for mitigation of the first-five harmonics (third, fifth, seventh, ninth, and eleventh harmonics), to reduce the complexity of the required procedure and to allocate few computational resource in the Field Programmable Gate Array (FPGA) based control board. Therefore, the voltage waveform taken into account is different respect traditional voltage waveform. The same concept, known as “voltage cancelation”, used for single-…
The Role of Human Resource Practices and Group Norms in the Retirement Process
2009
The present study analyzed retirement intentions and behavior as part of a work role withdrawal process. We examined the influences of the organizational and group contexts in the process of work role exit by means of two sources of work role expectations: human resource practices and group norms. Three different types of human resource practices were taken into consideration: performance enhancement practices, retirement enhancement practices, and organizational pressures toward retirement. Furthermore, three types of retirement indicators were analyzed: age considering retirement for the first time, early retirement intentions, and retirement age. Hierarchical regression analyses were ca…
L'approche sociologique des effets du contexte scolaire: méthodes et difficultés
2005
05058; International audience; L'analyse des effets contextuels dans le domaine de l'éducation constitue un champ derecherche en plein développement, dont les enjeux sont autant scientifiques que politiques.Le texte présente de manière précise comment les chercheurs en Education dont l'orientationest sociologique (ou économique) abordent ces questions, à partir d'une enquête récente,conduite au niveau de l'école primaire française, permettant d'évaluer et d'explorer ce typed'effets, en se focalisant sur l'influence de la composition sociale de la classe fréquentée. Letexte explicite la démarche et les étapes successives suivies, les modèles statistiques estiméset les difficultés méthodologi…
Organizzazione e diritto alla salute, alla prova della regionalizzazione e dell'aziendalizzazione dei servizi sanitari
2018
The contribution proposes an analysis of the effectiveness of the right to health, deepening the evolution of “regionalization” and “privatization of a state-owned company” of the National Health Service, in comparison with the marked regional differences (gaps) in the provision of Essential Levels of Assistance. The author researches the profile of the organization and of the financing of health services which take on a peculiar complexity in the health sector, in which there is the most complex experience of decentralization and also the introduction of fiscal federalism through the application of the requirement and the standard cost. For the purposes of overcoming health inequalities, t…
Quality of life and fear of COVID-19 in 2600 baccalaureate nursing students at five universities : a cross-sectional study
2021
Abstract Background The COVID-19 pandemic has caused significant disruptions in the implementation of programs across educational institutions. Nursing students, being both young adults and by practical training, part of the health care system, may be particularly vulnerable during the COVID-19 pandemic. The purpose of this study was to explore the associations between self-reported fear of COVID-19, general health, psychological distress and overall quality of life (QoL) in a sample of Norwegian baccalaureate nursing students compared to reference data. Methods The survey targeted baccalaureate nursing students from five universities in February 2021. An electronic questionnaire consisted …
When and how do hospital nurses cope with daily stressors? A multilevel study
2020
BackgroundDuring their workday, nurses face a variety of stressors that are dealt with using different coping strategies. One criticism of the contextual models of work stress is that they fail to focus on individual responses like coping with stress. Neverthless, little is know about the momentary determinants of coping in nurses.ObjectivesTo identify the momentary predictors of problem-focused approaching coping and emotion-focused approaching coping, as well as those for seeking social support and refusal coping strategies, during the working day in nurses.DesignThis study uses descriptive, correlational, two-level design with repeated measures.SettingsWards of two University hospitals.P…
Contributions to the study of educational returns
2016
In Tunisia, enrollment rates in tertiary education had soared up over the past two decades. A significant increase of student annual flows imposed the implementation of reforms that led to an increase in the number of higher education institutions and universities. One of the challenges in Tunisia and many African countries is to improve the efficiency of education systems to promote employability and graduates employment. This thesis discuss the question of the efficiency of education from an economic approach based on returns to education in the labor market. The first chapter analyses private returns to education particularly higher education in African countries. Our findings highlight …
Acceptability of domestic violence against women in the European Union: a multilevel analysis
2006
Study objective: The acceptability of domestic violence against women (DVAW) plays an important part in shaping the social environment in which the victims are embedded, which in turn may contribute either to perpetuate or to reduce the levels of DVAW in our societies. This study analyses correlates of the acceptability of DVAW in the European Union (EU). Design: Three level ordinal logistic regression of 13 457 people nested within 212 localities (cities), nested within 15 countries of the EU. Sampling is multistage with random probability. All interviews were face to face in people’s homes. The outcome variable was acceptability of DVAW. Multiple correlates at the individual, locality, an…
Contributions to the study of returns to education : the Tunisian case
2016
In Tunisia, enrollment rates in tertiary education had soared up over the past two decades. A significant increase of student annual flows imposed the implementation of reforms that led to an increase in the number of higher education institutions and universities. One of the challenges in Tunisia and many African countries is to improve the efficiency of education systems to promote employability and graduates employment. This thesis discuss the question of the efficiency of education from an economic approach based on returns to education in the labor market. The first chapter analyses private returns to education particularly higher education in African countries. Our findings highlight …