Accurate Analysis of Subharmonic Oscillations of V^2 and V^2Ic Controls Applied to Buck Converter

V2Ic control provides very fast dynamic performance to the Buck converter both under load steps and under voltage reference steps. However, the design of this control is complex since it is prone to subharmonic oscillations and several parameters affect the stability of the system. This paper derives and validates a very accurate modeling and stability analysis of a closed-loop V2Ic control using the Floquet theory. This allows the derivation of sensitivity analysis to design a robust converter. The proposed methodology is validated on a 5-MHz Buck converter. The work is also extended to V2 control using the same methodology, showing high accuracy and robustness. The paper also demonstrates, on the V2 control, that even a low bandwidth-linear controller can affect the stability of a ripple-based control.

Avaliação de Desempenho: será um processo considerado como justo?

O presente estudo procura estabelecer a relação entre a Percepção de Justiça e Satisfação com o Sistema de Avaliação de Desempenho. A metodologia utilizada foi a quantitativa, pois permite validar a revisão da literatura efetuada, onde se procura analisar a relação entre a Percepção de Justiça e a Satisfação com o Sistema de Avaliação de Desempenho através de um conjunto de hipóteses que posteriormente serão testadas. Para se testar as hipóteses recolheu-se os dados através da adaptação de um questionário já aplicado em Portugal (Porfírio, 2006). O mesmo foi aplicado a 89 funcionários de uma empresa do ramo Transitário. Para o tratamento dos dados recolhidos vai ser utilizado o programa IBM SPSS Statistics 20. De acordo com os resultados obtidos verificou-se que existe uma relação positiva e significativa entre a Percepção de Justiça na dimensão Distributiva e a Satisfação com o Sistema de Avaliação de Desempenho. Não se tendo verificado o mesmo para a dimensão Procedimental. Em relação ao Big Five podemos constatar que é significativo e que exerce controlo entre a Percepção de Justiça Distributiva e a Satisfação com o Sistema de Avaliação de Desempenho, não se tendo comprovado o mesmo para a Percepção de Justiça Procedimental.

Criticizing groups from the inside and the outside: An identity perspective on the intergroup sensitivity effect

Research on group criticism has demonstrated that criticisms are received less defensively when made by an ingroup member than when made by an outsider (the intergroup sensitivity effect). Three experiments tested the extent to which this effect is driven by social identity concerns or by judgments of how experienced the source of the criticism is. In Experiments I and 2, Australians who criticized Australia (ingroup critics) were met with less defensiveness than were foreigners who criticized Australia (outgroup critics), regardless of the amount of experience the foreigner had with Australia. Furthermore, the effects of speaker type on evaluations were mediated by perceptions of the extent to which the criticisms were intended to be constructive but not by perceptions of experience. Finally, Experiment 3 indicated that although experience does not help outgroup critics, a lack of experience can hurt ingroup critics. Recommendations are provided as to how people can reduce defensiveness when making group criticisms.

The dynamics of HRM systems in Indian BPO firms

This paper highlights the context within which business process outsourcing (BPO) has rapidly grown in India and the critical need to investigate the dynamics of human resource management (HRM) practices and systems in this sector. Using a mixed-method approach involving both in-depth interviews and self-completing questionnaires, we analyze the nature of HRM systems in BPO organizations operating in India. The analysis is based on a sample of 51 BPO companies, a majority of which are located near the capital of New Delhi. The results focus on the nature and structure of work and organization of Indian BPOs, as well as the strategic role played by HRM in such organizations. Furthermore, the findings highlight the way specific HRM practices such as recruitment, performance appraisal, training and development, and compensations are implemented. Our study suggests the existence of formal, structured, and rationalized HRM systems in Indian BPOs. A number of insights related to HRM policies and practices are shared by the HR managers interviewed shedding more light on the inner workings of the Indian BPO companies and their challenges. The analysis provides original and useful information to both academics and practitioners and opens avenues for future research on the nature of HRM systems and practices in the Indian BPO industry.

The adsorptive separation of aromatic hydrocarbon mixtures

A detailed study has been made of the feasibility of adsorptive purification of slack waxes from traces of aromatic compounds using type 13X molecular sieves to achieve 0.01% aromatics in the product. The limited literature relating to the adsorption of high molecular weight aromatic compounds by zeolites was reviewed. Equilibrium isotherms were determined for typical individual aromatic compounds. Lower molecular weight, or more compact, molecules were preferentially adsorbed and the number of molecules captured by one unit cell decreased with increasing molecular weight of the adsorbate. An increase in adsorption temperature resulted in a decrease in the adsorption value. The isosteric heat of adsorption of differnt types of aromatic compounds was determined from pairs of isotherms at 303 K to 343 K at specific coverages. The lowest heats of adsorption were for dodecylbenzene and phenanthrene. Kinetics of adsorption were studied for different aromatic compounds. The diffusivity decreased significantly when a long alkyl chain was attached to the benzene ring e.g. in dodecylbenzene; molecules with small cross-sectional diameter e.g. cumene were adsorbed most rapidly. The sorption rate increased with temperature. Apparent activation energies increased with increasing polarity. In a study of the dynamic adsorption of selected aromatic compounds from binary solutions in isooctane or n-alkanes, naphthalene exhibited the best dynamic properties followed by dibenzothiophene and finally dodecylbenzene. The dynamic adsorption of naphthalene from different n-alkane solvents increased with a decrease in solvent molecular weight. A tentative mathematical approach is proposed for the prediction of dynamic breakthrough curves from equilibrium isotherms and kinetic data. The dynamic properties of liquid phase adsorption of aromatics from slack waxes were studied at different temperatures and concentrations. The optimum operating temperature was 543 K. The best dynamic performance was achieved with feeds of low aromatic content. The studies with individual aromatic compounds demonstrated the affinity of type NaX molecular sieves to adsorb aromatics in the concentration range 3% - 5% . Wax purification by adsorption was considered promising and extension of the experimental programme was recommended.

Aspects of design for a spare parts provisioning system

This thesis describes an investigation by the author into the spares operation of compare BroomWade Ltd. Whilst the complete system, including the warehousing and distribution functions, was investigated, the thesis concentrates on the provisioning aspect of the spares supply problem. Analysis of the historical data showed the presence of significant fluctuations in all the measures of system performance. Two Industrial Dynamics simulation models were developed to study this phenomena. The models showed that any fluctuation in end customer demand would be amplified as it passed through the distributor and warehouse stock control systems. The evidence from the historical data available supported this view of the system's operation. The models were utilised to determine which parts of the total system could be expected to exert a critical influence on its performance. The lead time parameters of the supply sector were found to be critical and further study showed that the manner in which the lead time changed with work in progress levels was also an important factor. The problem therefore resolved into the design of a spares manufacturing system. Which exhibited the appropriate dynamic performance characteristics. The gross level of entity presentation, inherent in the Industrial Dynamics methodology, was found to limit the value of these models in the development of detail design proposals. Accordingly, an interacting job shop simulation package was developed to allow detailed evaluation of organisational factors on the performance characteristics of a manufacturing system. The package was used to develop a design for a pilot spares production unit. The need for a manufacturing system to perform successfully under conditions of fluctuating demand is not limited to the spares field. Thus, although the spares exercise provides an example of the approach, the concepts and techniques developed can be considered to have broad application throughout batch manufacturing industry.

The study and measurements of the behaviour and characteristics of electromagnetic relays

The thesis presents a theoretical and practical study of the dynamic behaviour of electromagnetic relays. After discussing the problem of solving the dynamicc equations analytically and presenting a historical survey of the earlier works in the relay and its dynamics, the simulation of a relay on the analogue computer is discussed. It is shown that the simulation may be used to obtain specific solutions to the dynamic equations. The computer analysis provides the dynamic characteristics for design purposes and may be used in the study of bouncing, rebound oscillations and stability of the armature motion. An approximate analytical solution to the two dynamic equations is given based on the assumption that the dynamic variation of the pull with the position of the armature is linear. The assumption is supported by the Computer-aided analysis and experimental results. The solution is intended to provide a basis for a rational design. A rigorous method of analysing the dynamic performance by using Ahlberg's theory is also presented. This method may be justified to be the extension of Ahlberg's theory by taking the mass and frictional damping forces into account. While calculating the armature motion mathematically, Ahlberg considers the equilibrium of two kinds of forces, namely pull and load, and disregards the mass and friction forces, whereas the present method deals with the equilibrium of all four kinds of forces. It is shown how this can be utilised to calculate the dynamic characteristics for a specific design. The utility of this method also extends to the study of stability, contact bounce and armature rebound. The magnetic circuit and other related topics which are essential to the study of relay dynamics are discussed and some necessary experimental results are given.

Simulation and experimental analysis of a brushless electrically excited synchronous machine with a hybrid rotor

Electrically excited synchronous machines with brushes and slip rings are popular but hardly used in inflammable and explosive environments. This paper proposes a new brushless electrically excited synchronous motor with a hybrid rotor. It eliminates the use of brushes and slip rings so as to improve the reliability and cost-effectiveness of the traction drive. The proposed motor is characterized with two sets of stator windings with two different pole numbers to provide excitation and drive torque independently. This paper introduces the structure and operating principle of the machine, followed by the analysis of the air-gap magnetic field using the finite-element method. The influence of the excitation winding's pole number on the coupling capability is studied and the operating characteristics of the machine are simulated. These are further examined by the experimental tests on a 16 kW prototype motor. The machine is proved to have good static and dynamic performance, which meets the stringent requirements for traction applications.

Vezetői döntéshozatal és versenyképesség (The managerial decision making and the competitiveness)

A tanulmány a vezetői döntéshozatal három lényeges aspektusát tárja fel. A Versenyben a világgal c. kutatási program eredményei alapján arra lehet következtetni, hogy a menedzserek döntéshozatali képességei és megközelítései, a vállalati teljesítménymérés és menedzsment döntéseket támogató szerepe, valamint a vállalatok érintettekhez fűződő viszonya meghatározó lehet a hatékony vezetői döntéshozatal során. A vállalati döntéshozatal jellemzőinek bemutatása után megvizsgáljuk azt is, hogy a különböző teljesítményű cégek döntéseit mennyire támogatja a menedzserek felkészültsége, a teljesítménymérési gyakorlat és az érintettek elvárásai. A szerzők úgy találták, hogy a fenti tényezők mindegyike hozzájárul a hazai cégek versenyképességéhez, általánosságban ugyanis elmondható, hogy a döntéseket támogató vállalati környezet jobb üzleti teljesítményhez és gyorsabb reagálóképességhez vezethet. Az eredmények összegzése mellett ajánlásokkal is éltek a vállalatok számára, amelyek alkalmazásával hatékonyabb döntéseket hozhatnak. _______ This study presents three main aspects of the managerial decision making. Based on the results of the research program In competition with the World it points to the fact that decision making abilities and approaches of the managers, the corporate performance appraisal and the management decision support role, and the corporate relations to the stakeholders will be determinant in the process of the efficient managerial decision making. After presentation of characteristics of the corporate decision making the authors examine that how the decisions of enterprises with different performances are supported by the preparedness of the managers, the performance appraisal practice and the stakeholders expectations. The authors have thought that every factor contributes to the competitiveness of the domestic enterprises, and generally the decision supporting corporate environment can lead to better business performance and faster responsive abilities. Besides the results summary the authors give useful recommendations to the corporations with which they can make more efficient decisions.

Team Evaluation: Solutions for Hotel Management and Productivity

Employee performance appraisal systems are controversial, especially when accomplished by a single rater. The authors, who have had experience with team evaluation systems, present evidence from that experience for over- coming obstacles to moving to a "less-biased" system of rating employees.

Estratégias para obtenção de adequada iluminação natural em escolas: uma análise de sistemas de aberturas para Natal/RN

The purpose of this research is to analyze different daylighting systems in schools in the city of Natal/RN. Although with the abundantly daylight available locally, there are a scarce and diffuse architectural recommendations relating sky conditions, dimensions of daylight systems, shading, fraction of sky visibility, required illuminance, glare, period of occupation and depth of the lit area. This research explores different selected apertures systems to explore the potential of natural light for each system. The method has divided into three phases: The first phase is the modeling which involves the construction of three-dimensional model of a classroom in Sketchup software 2014, which is featured in follow recommendations presented in the literature to obtain a good quality of environmental comfort in school settings. The second phase is the dynamic performance computer simulation of the light through the Daysim software. The input data are the climate file of 2009 the city of Natal / RN, the classroom volumetry in 3ds format with the assignment of optical properties of each surface, the sensor mapping file and the user load file . The results produced in the simulation are organized in a spreadsheet prepared by Carvalho (2014) to determine the occurrence of useful daylight illuminance (UDI) in the range of 300 to 3000lux and build graphics illuminance curves and contours of UDI to identify the uniformity of distribution light, the need of the minimum level of illuminance and the occurrence of glare.

O Sistema de Gestão e Avaliação do Desempenho na Administração Pública Portuguesa: efeitos da sua prática no contrato psicológico dos colaboradores

Desde as últimas décadas do século XX que, perante um cenário marcado pela complexidade de uma economia globalizada, a Administração Pública tem sido coagida a passar por processos de reforma. As referências à reestruturação da Administração Pública por motivos políticos, económicos e financeiros, são frequentes na literatura, e surgem, quase sempre, num discurso imperativo. Neste contexto, foram introduzidos mecanismos de mercado por se acreditar que estes produzem soluções mais eficazes para o cidadão-cliente, uma administração motivadora, para quantos nela trabalham, e eficiência económica. Na esfera pública, mais do que transformar inputs em outputs, importa, avaliar os outcomes, isto é, o impacto sobre o valor público. Inúmeros estudos concorreram para enquadrar e justificar a reforma do sector público. Continuam, porém, a faltar respostas de como compatibilizar a gestão orçamental com práticas ideológicas das organizações, nomeadamente ao nível da gestão de recursos humanos. Este estudo tem como objectivo central contribuir para um melhor conhecimento dos efeitos que a prática da avaliação do desempenho, em vigor na Administração Pública Portuguesa, tem no contrato psicológico dos colaboradores. Para o teste das hipóteses propusemos um modelo de investigação, tomando como referência a teoria de Guest. Com uma abordagem qualitativa, construímos um inquérito por questionário, que foi aplicado a alguns colaboradores de uma Instituição pública. Os dados recolhidos permitiram a elaboração de quadros de referência de resultados que, por meio da análise de conteúdo, nos possibilitou tirar ilações acerca do comprometimento organizacional e comportamentos de cidadania organizacional dos Colaboradores. Trata-se de uma pesquisa com características exploratórias que, acreditamos, possa ser a base para trabalhos futuros sobre os efeitos do SIADAP nos indivíduos e nas organizações. Os resultados mostram que o sentimento de que a organização não cumpriu os termos do contrato psicológico é moderado por um esforço emocional, que mantém o colaborador na organização, evidenciando, ainda, um comprometimento afectivo com a Instituição e comportamentos de virtude cívica. / Since the last decades of the 20th century, in a scenario marked by the complexity of a globalized economy, the Public Administration has been forced to undergo reform processes. References to the restructuring of the Public Administration for political, economical and financial reasons are frequent in literature, and arise, in most cases, in an imperative tone. In this context, market mechanisms were introduced, as it is believed that they produce more efficient solutions for the citizen-client, motivated administration for whom many work, and economic efficiency. In the public sphere, more than just transforming inputs into outputs, it is important to evaluate the outcomes, that is, the impact on the public value. Numerous studies have contributed to contextualize and justify the public sector reform. However, there are still no answers of how to develop compatibility between the budgetary management and the ideological practices of the organizations, namely on the level of human resource management. The main aim of this study is to contribute to a better knowledge of the effects that the practice of performance appraisal, in force in the Portuguese Public Administration, has on the employee's psychological contract. For this hypothesis test, we proposed a research model, with reference to Guest's theory. With a qualitative approach, we constructed a survey questionnaire that was applied to some employees of a Public Institution. The data gathered allowed the elaboration of results frameworks which, by means of the content analysis, enabled us to draw conclusions of the employees' organizational commitment and organizational citizenship behaviour. It is a research with exploratory characteristics, which we believe, may provide the basis for future work on the effects of the SIADAP on individuals and organizations. The results indicate that the feeling that the organization did not fulfil the psychological contract terms is moderated by an emotional effort, which leads the employee to remain in the organization, also showing an affective commitment to the institution and civic virtue behaviours.

Perceções de (In)Justiça na Avaliação de Desempenho das Forças de Venda: estudo em empresas do sector farmacêutico

Num mundo competitivo com alterações profundas nos processos de trabalho e desempenho, surgem necessidades de novas formas de avaliação e competências profissionais. Estas necessidades promovem um ambiente nem sempre justo e saudável, algo imprescindível para o bem-estar de uma organização. O presente estudo objetiva verificar perceções de justiça organizacional da avaliação de desempenho de duas empresas do sector farmacêutico (empresa A e empresa B). Do mesmo modo verifica-se de que forma as variáveis sociodemográficas afetam ou fragmentam a avaliação de desempenho. Este tema é pouco explorado em Portugal, contribuindo para o aprofundamento da compreensão da multidimensionalidade da perceção de justiça nas forças de vendas destas organizações. A pesquisa descritiva foi realizada por meio de levantamento, com assertivas extraídas da pesquisa de Sotomayor (2006), para investigar as perceções de justiça distributiva, processual, interpessoal e informacional. Os resultados obtidos neste estudo indicam perceção de justiça organizacional na avaliação de desempenho por parte da força de vendas em todas as quatro dimensões distintas, apresentando a justiça procedimental um score de destaque, seguida da justiça distributiva. A organização B apresenta níveis mais elevados de prevalência de justiça distributiva, procedimental, interpessoal e informacional face à organização A. No que respeita à relação entre as variáveis sociodemográficas e à perceção de justiça na avaliação de desempenho, a mesma não é suportada nesta amostra não comprometendo a perceção de justiça. Do presente estudo retira-se o quanto determinante nas organizações que envolvem forças de venda são as políticas e práticas de gestão de desempenho, acautelando o sucesso estratégico sustentado da organização, percecionando que com estas a organização as valoriza e cuida do seu bem-estar, com perceções positivas de justiça na avaliação de desempenho. / In a competitive world with profound changes in work processes and performance needs arise new forms of evaluation and professional skills. These needs foster an environment not always fair and healthy, something essential for the well-being of an organization. This study aims to verify perception of organizational justice evaluation of performance of two companies in the pharmaceutical sector (company A and company B). Likewise there is how sociodemographic varia-bles affect or fragmenting the performance appraisal. This theme is underexplored in Portugal, contributing to the deepening of understanding of the multidimensionality of perception of justice in these organizations sales forces. The descriptive research was conducted through survey, with the extracted assertions Sotomayor research (2006), to investigate the perceptions of distributive, procedural, interpersonal and informational justice. The results of this study indicate organizational justice perception on performance appraisal by the sales force in all four different dimensions, presenting procedural justice an outstanding score, followed by distributive justice. The organization B has higher levels of prevalence of distributive justice, procedural, interpersonal and informational face the organization A. As regards the relationship between sociodemographic variables and the perception of justice in performance appraisal, it is not supported in this sample does not compromising the perception of justice. The present study withdraws how decisive in organizations involving sales force policies and performance management practices, cautioning sustained strategic success of the organization, perceived that the organization values and cares for your well-being, with positive perceptions justice in performance appraisal.

Avaliação de desempenho e o compromisso face ao superior hierárquico

Mestrado em Contabilidade e Gestão das Instituições Financeiras