Les environnements virtuels (EVs) sont de plus en plus utilisés dans le domaine de la recherche et de la clinique avec pour avantage que chaque environnement peut être adapté au besoin du participant mais avec pour inconvénient que la pluralité des variables mesurées lors des tests virtuels rend la performance du sujet de plus en plus difficile à expertiser. L’objectif de la thèse est de proposer une approche permettant de qualifier, de façon la plus pertinente possible, la performance du participant dans un EV en tentant de comprendre la charge mentale associée à chaque technique d’interaction et comment celle-ci peut venir influencer la performance du participant. Cinquante-trois participants ont réalisé des tâches dans un EV avec une des cinq techniques d’interaction disponible : la souris, le gamepad, le Razer Hydra, le Razer Hydra avec un tracking de tête et le Razer Hydra avec un casque de RV. Ils étaient attribués à une des deux conditions de difficulté de la tâche : une facile et une difficile avec des tâches additionnelles. Le rythme cardiaque du participant était enregistré et ceux-ci ont renseigné des questionnaires de charge mentale, présence et cybermalaise. L’expérimentation a permis de mettre en avant que la différence de charge mentale entre les différentes techniques d’interaction est faible et que celle-ci se manifeste plus sensiblement lorsque les techniques sont regroupées par leurs caractéristiques. Ainsi les techniques avec une sélection en 3D et un steering effectué par les mouvements de la tête demande plus de charge mentale. Le degré d’expertise avec l’utilisation d’une technique d’interaction n’est pas lié à une modulation de la charge mentale. Cependant les utilisateurs qualifiés d’experts sont plus à même d’explorer le VMT que les novices. De plus, la charge mentale est plus perçue dans les conditions où la difficulté de la tâche est faible alors que dans le cas où la difficulté de la tâche est élevée, ce sont les problèmes d’utilisabilité des techniques d’interaction qui s’expriment. Les participants qui ont une charge mentale élevée ont un score plus faible que les participants qui ont une faible charge mentale, en particulier lors des tâches qui réclament des fonctions cognitives variées. / Virtual environments (Ves) can be modulated and be adapted to the need of each user but the several variables used during cognitiv assessment during virtual tests give the user’s performance uneasy to expertise. The objective of the thesis is to propose an approach to qualify user performance taking acount of his/her workload during the task realization. Fifty-three participants realiazed tasks in a VE with one of five interaction technique: mouse, gamepad, Razer Hydra, Razer Hydra and head tracking and Razer Hydra and HMD. They participate in one of the two conditions: the easy one or the more difficult with additionnal tasks. Heart rate, workload, presence and cybersickness were measured. Results showed that there is only a weak difference of workload accross the several interaction technique and the difference is stronger when interaction technique are grouped according their similiarities. Interaction with 3D selection and with head steering ask for more workload. User habilities with the use of an interaction technique is not related to workload but experts are more likely to explore the VE. What’s more the perceived workload is higher in easy condition whereas usability issues are perceived higher in hard condition. Users with high workload have lower score than those with low workload especially for tasks with high cognitiv demand.

The purpose of this thesis is to understand the opinions and potential effects of objective and subjective assessments of performance as a basis for performance pay for blue-collar workers. The study takes a qualitative approach to find out how and why four companies - Trelleborg Forsheda, Finnveden Powertrain, Isaberg Rapid and Parker Hannifin- work with salaries, incentive system and performance assessment the way they do. The concept of individual salary is central in this thesis, and individual salary is based on four criteria; capabilities, performance, work demand and formal competence. These can be divided in subjective or objective criteria. Individual salaries also contribute to salary divergence, which in many studies have indicated higher performance. Important to remember is that it has to exist a purpose to salary divergence and how salary is diverged in the company is related to the goals and strategy of the company. If the company chooses to have performance based salaries- which is salary divergence- another question arise; what is good performance? In organizations that have performance salaries, a group or an individual (often the middle manager) have to decide if a certain group of personnel performs good or bad. This can mainly be done in two different ways; objective performance assessment or subjective performance assessment. Objective performance assessment is based on numerical calculation of measures, which will form the basis for rewarding employees using a salary system that reward performance. Subjective performance measurements are based on judgment. Instead of relying on numerical calculations, one evaluates if the results reflect good or bad performance. For both methods it is essential that the personnel feels that the salaries are fair, and that the salary system is clear and easy to understand. Something else that is important to understand is that employer and employee have different views in what is a fair salary. Objective assessments are based on numerical calculations of measures, and one important property such measures have is that they don’t leave any room for excuses. Research indicate that performance pay has important motivation enhancing effects, but the profitability doesn’t always benefit from it. When monitoring costs are high, or product quality or long term thinking is required, hourly wages may be preferable. Tasks which are measured, will naturally be prioritized by the organization. This means that the choice of measures is very important. The amount of measures mustn’t be too high, and they have to be carefully considered. Subjective assessments are the opposite to objective ones. The advantages with subjective performance assessments are, among other things, that additional information which have surfaced during the period of measurements can be taken into consideration, errors in the measurement process can be corrected and unlucky circumstances can be dealt with. However, problems exist in unfair assessments, which are based on prejudice. Findings in this report shows that profitable companies have large differences in their salary systems. This is also supported by other research. The company Isaberg Rapid AB only uses objective criteria, focused on simplicity and group rewards. Finnveden Powertrain on the other hand, has a system focused on individuals and subjective assessments. Some conclusions could be drawn; one of the most important being that connections between the type of activities and the salary system is positive, and that salary systems have to be updated and revised continuously.

Control performance assessment (CPA) is an important tool to realize high performance control systems in manufacturing plants. CPA of both continuous and batch processes have attracted much attention from researchers, but only a few results about semiconductor processes have been proposed previously. This work provides methods for performance assessment and diagnosis of the run-to-run control system used in high-mix semiconductor manufacturing processes. First, the output error source of the processes with a run-to-run EWMA controller is analyzed and a CPA method (namely CPA I) is proposed based on closed-loop parameter estimation. In CPA I, ARMAX regression is directly applied to the process output error, and the performance index is defined based on the variance of the regression results. The influence of plant model mismatch in the process gain and disturbance model parameter to the control performance in the cases with or without set point change is studied. CPA I method is applied to diagnose the plant model mismatch in the case with set point change. Second, an advanced CPA method (namely CPA II) is developed to assess the control performance degradation in the case without set point change. An estimated disturbance is generated by a filter, and ARMAX regression method is applied to the estimated disturbance to assess the control performance. The influence of plant model mismatch, improper controller tuning, metrology delay, and high-mix process parameters is studied and the results showed that CPA II method can quickly identify, diagnose and correct the control performance degradation. The CPA II method is applied to industrial data from a high-mix photolithography process in Texas Instruments and the influence of metrology delay and plant model mismatch is discussed. A control performance optimization (CPO) method based on analysis of estimated disturbance is proposed, and optimal EWMA controller tuning factor is suggested. Finally, the CPA II method is applied to non-threaded run-to-run controller which is developed based on state estimation and Kalman filter. Overall process control performance and state estimation behavior are assessed. The influence of plant model mismatch and improper selection of different controller variables is studied. / text

Aim of the paper: to analyze performance peculiarities of primary health care organizations (PHCO) and to propose possible ways for improvement. Methods: the analysis of scientific literature of Lithuanian and foreign authors, analysis of legal regulating documents, analysis of the results of the questionnaire of managers of PHCO, analysis of the results of the interview with experts. The object of research: performance assessment of primary health care organizations. Results: PHCO quality assessment and assessment performed by administrative organizations are the most often types of PHCO assessment in Lithuania. The results of the research show that data evaluating PHCO performance are fragmented and reflect only certain areas of PHCO activities. The quantity of the data does not correspond to the needs of PHCP managers in the strategic planning and implementation process. The assessment of PHCO performance is not dynamic and adjusted to the changing environment conditions. Experts unanimously pointed the need for the development of present PHCO performance assessment system and the need for its unification. Conclusions and practical recommendations: 1. Having done the analysis of scientific literature, we may conclude that problems of performance assessment are most often analyzed in business than in public sectors. The complex view to organization activities allows to analyze not only results of the organization, quality of performance but also to identify areas for... [to full text]

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Assessment of science process skills in the elementary school is essential to a hands-on science program. Concern arises with the realization that there are few performance assessment instruments of science process skills, and most of the available instruments do not have documented reliability and validity standards. This study examines the reliability and validity of a set of science performance assessment instruments through the application of currently available statistical methods. The Performance Assessment of Science Skills (PASS) tests, which were formulated by S. M. Johnson as an alternative assessment of science process skills in the elementary school grades, are the subject of investigation.Third-grade students completed PASS instruments which measured the process skills of observation, binary classification, and measurement, and fifth-grade students completed PASS instruments which measured the science process skills of prediction, designing a controlled experiment, and hierarchicalclassification.Reliability and validity for the PASS instruments focused on alternate form reliability, internal reliability, inter-rater reliability and construct validity. This study revealed that statistical reliability and validity can be documented for some alternative assessments of science process skills. / Department of Biology

Thesis (D. Ed.) -- University of Maryland, College Park, 2004. / Thesis research directed by: Education Policy, and Leadership. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

O escopo desta dissertação é o desenvolvimento de uma metodologia para identificar os modelos de canais da matriz dinâmica que estejam degradando o desempenho de controladores preditivos, ou MPC (Model Predictive Control), baseado nas técnicas de auditoria e diagnóstico deste tipo de controlador propostas por BOTELHO et al. (2015) e BOTELHO; TRIERWEILER; FARENZENA (2016) e CLARO (2016). A metodologia desenvolvida contempla dois métodos distintos. O primeiro, chamado método direto compensado, tem como base o método direto de identificação em malha fechada (LJUNG, 1987)e compensa cada saída medida do processo de modo a se reter apenas a contribuição do canal que se deseja identificar. O segundo, chamado método do erro nominal, utiliza a definição de saída nominal do processo, proposta por BOTELHO et al. (2015), como métrica para se quantificar o quão próximo o modelo está do comportamento da planta através da minimização do erro nominal. Os métodos foram aplicados ao sistema de quatro tanques cilíndricos (JOHANSSON, 2000) para dois cenários distintos, sendo o primeiro um sistema 2x2 em fase não mínima contendo um MPC trabalhando com setpoint e o segundo um sistema 4x4 em fase mínima com o MPC atuando por faixas. Para o sistema 2x2, se avaliou a influência da localização do canal discrepante (dentro ou fora da diagonal principal da matriz dinâmica de transferência) na eficácia dos métodos. Para o sistema 4x4, o estudo foi voltado para a eficácia dos métodos frentes a controladores que atuam dentro de limites para as variáveis. Os modelos identificados foram comparados pela capacidade de identificar um modelo que capturasse o zero de transmissão da planta e o RGA dinâmico, par ao sistema 2x2, e pelas respostas degrau e diagrama de Bode para o sistema 4x4. O método direto compensado resultou em baixo erro relativo no valor do zero para a discrepância na diagonal principal da matriz dinâmica e alto valor quando a discrepância se encontrava fora da diagonal principal. O método do erro nominal, por sua vez, foi capaz de identificar um modelo cujo zero de transmissão possuía baixo erro relativo frente ao zero da planta em ambos os cenários. No cenário do controlador atuando por faixas, os métodos propostos obtiveram melhores estimativas dos modelos quando comparados com o método concorrente, uma vez que apresentou alto percentual de aderência das saídas simuladas com as saídas medidas. Em todos os cenários estudados, o método do erro nominal se mostrou capaz de identificar um modelo mais robusto, pois este apresentou RGA dinâmico compatível com a planta em todo o range de frequências analisado. / The objective of this dissertation is to develop a method to identify the model for the channel of the dynamic matrix that are affecting the performance of model predictive controllers (MPC), based on the assessment and diagnosis techniques for this type of controller proposed by BOTELHO et al. (2015) e BOTELHO; TRIERWEILER; FARENZENA (2016) and CLARO (2016). The proposed methodology includes two different methods. The first, called the compensated direct method, is based on the closed-loop direct identification method (LJUNG, 1987) and compensates each process measured output in order to retain only the contribution of the channel being identified. The second, called nominal error method, uses the definition of the process nominal output, proposed by BOTELHO et al. (2015), as a metric to quantify how close the model is to the actual plant behavior by minimizing the nominal error. The proposed methods were applied to the quadruple-tank system (JOHANSSON, 2000) for two distinct scenarios, the first being a nonminimum-phase 2x2 system containing a MPC working with setpoint and the second a minimum-phase 4x4 system with the MPC working by ranges. For the 2x2 system, the influence of the model mismatch location (inside or outside the main diagonal of the dynamic transfer matrix) on the effectiveness of the methods was evaluated. For the 4x4 system, the study was focused on the effectiveness of the methods with controllers that operate within limits for the variables. The identified models were compared by the capability of identifying a model with accurate plant transmission zero and dynamic RGA, for the 2x2 system, and by the step responses and Bode diagram for the 4x4 system. The compensated direct method resulted in low relative error in the value of the transmission zero for the model mismatch located in the main diagonal of the dynamic matrix and high relative error when the mismatch was outside the main diagonal. On the other hand, the nominal error method was able to identify a model whose transmission zero had low relative error against the plant zero in both scenarios. In the scenario of a controller working by range, the proposed methods obtained better estimates of the models when compared to the concurrent method, since it presented a high percentage of adherence of the simulated outputs with the measured outputs. In all the studied scenarios, the nominal error method was able to identify a more robust model, since it presented dynamic RGA compatible with the plant in the entire range of analyzed frequencies.

Diminuir a variabilidade de variáveis chaves do processo tornou-se um dos principais caminhos para quantificar os benefícios potenciais da melhoria do controle de processos, ou seja, com maior confiabilidade dos resultados é possível trabalhar em uma região próxima ao ponto de operação ótimo, o que se converte em ganho. Tal ganho pode ser materializado na forma de aumento da capacidade de produção da unidade, redução do consumo de energia, decréscimo de produtos fora de especificação, redução do tempo de transição entre produtos, melhoria na operabilidade, melhoria na qualidade final do produto, entre outros. Na presente dissertação é realizada uma revisão das principais metodologias que visam quantificar o potencial de alteração de variabilidade a qual uma malha de controle possa estar sujeita, além de propor um modelo de inferência que possa ser utilizado para predizer esse potencial de alteração de variabilidade, baseado em índices dados pelo Modelo de Inferência para Desempenho e Robustez. Neste trabalho é mostrado o procedimento utilizado para a construção do Modelo de Inferência de Variabilidade, o qual utiliza como entradas índices que possam ser facilmente quantificáveis e de características da planta (tempo morto e constante de tempo), usando somente dados em operação normal (sem mudanças no valor do setpoint). Para a sua obtenção, três diferentes métodos foram testados (a saber, Rede Neural, Mínimos Quadrados Parciais e Mínimos Quadrados Parciais Quadráticos), sendo os melhores resultados conseguidos ao se aplicar redes neurais. A eficácia do modelo de inferência proposto é ilustrada pela aplicação em casos de estudo nos quais o modelo de planta pode ser representado por funções de transferência de 1ª e de 2ª ordem com tempo morto e a aplicabilidade do mesmo é ilustrada ao utilizá-lo em um caso de estudo, desenvolvido em uma planta industrial. Nesse caso de estudo, procurou-se ainda analisar as principais malhas encontradas no cenário industrial. Os resultados obtidos para ambos os casos de estudo mostraram que a ferramenta desenvolvida apresenta um grande potencial de ser utilizada em projetos que contemplem a análise de pontos de melhoria da camada regulatória, uma vez que apresenta uma excelente capacidade de predizer a alteração de variabilidade a qual uma malha possa estar sujeita. / Reduction of the process variability has a significant impact into the process profitability. A reduction in the variance allows shifting the mean of the controlled variable closer to the constraint and thus ensures better performance like increase product throughput, increase yield of higher valued products, improve energy efficiency, decrease off-specification product, safer operation and reduced environmental impact, among others. In this dissertation, a bibliographic review of the main methodology used to estimate and assess the variance reduction is done. The main contribution of this work is to propose an inferential model to estimate the potential alteration in variance, based on indices determined by the Performance and Robustness Inferential Model. This work shows the procedure to build the Variability Inferential Model that assesses the potential alteration in variance of a given loop. The inputs variables are indices that can be easily calculated on-line and information about the plant (time delay and time constant) using only normal operating data (without excitation and/or setpoint activity). The set of input – output variables are fitted using different techniques (i.e., Neural Networks, Partial Least Squares and Quadratic Partial Least Squares). The best results are obtained by Neural Network. The efficacy of the Inferential Model is illustrated by application to first order plus time delay and second order plus time delay models. The proposed methodology was also applied to on a polyolefin plant, providing very good results, in a set of five loops, where the potential variance alteration is computed with small error, showing the efficacy of the methodology.

Este trabalho estuda o problema de seleção de carteiras de variância mínima com base em uma recente metodologia para otimização de carteiras com restrições nas normas das exposições brutas proposta por Fan, Zhang e Yu (2012). Para esse propósito, consideram-se diferentes estimadores da matriz de covariâncias condicional e incondicional. A grande contribuição deste artigo é de natureza empírica para o mercado de ações brasileiro. Avaliam-se índices de desempenho fora da amostra das carteiras construídas para um conjunto de 61 ações negociadas na Bolsa de Valores de São Paulo (BM&FBovespa). Os resultados mostraram que as restrições nas normas dos vetores de alocação (restrição de exposição bruta) geram ganhos substanciais em relação às carteiras restringidas para venda a descoberto, aumentando o retorno médio ajustado pelo risco e diminuindo o turnover dos portfólios. / This paper studies the problem of minimum variance portfolio selection based on a recent methodology for portfolio optimization restricting the allocation vector proposed by Fan, Zhang e Yu (2012). To achieve this, different conditional and inconditional covariance matrix estimators are considered. The great contribuition of this paper is one of empirical nature for the brazilian stock market. We evaluate out-of-sample performance indexes for the portfolios constructed for a set with 61 different sotcks traded in the São Paulo stock exchange (BM&FBovespa). The results show that the restrictions on the norms of the allocation vector generate substantial gains compared to the no short-sale portfolio, raising the average return adjusted by the risk and lowering the portfolio turnover.