Parallel Coupled Micro-Macro Actuators

This thesis presents a new actuator system consisting of a micro-actuator and a macro-actuator coupled in parallel via a compliant transmission. The system is called the Parallel Coupled Micro-Macro Actuator, or PaCMMA. In this system, the micro-actuator is capable of high bandwidth force control due to its low mass and direct-drive connection to the output shaft. The compliant transmission of the macro-actuator reduces the impedance (stiffness) at the output shaft and increases the dynamic range of force. Performance improvement over single actuator systems was expected in force control, impedance control, force distortion and reduction of transient impact forces. A set of quantitative measures is proposed and the actuator system is evaluated against them: Force Control Bandwidth, Position Bandwidth, Dynamic Range, Impact Force, Impedance ("Backdriveability'"), Force Distortion and Force Performance Space. Several theoretical performance limits are derived from the saturation limits of the system. A control law is proposed and control system performance is compared to the theoretical limits. A prototype testbed was built using permanenent magnet motors and an experimental comparison was performed between this actuator concept and two single actuator systems. The following performance was observed: Force bandwidth of 56Hz, Torque Dynamic Range of 800:1, Peak Torque of 1040mNm, Minimum Torque of 1.3mNm. Peak Impact Force was reduced by an order of magnitude. Distortion at small amplitudes was reduced substantially. Backdriven impedance was reduced by 2-3 orders of magnitude. This actuator system shows promise for manipulator design as well as psychophysical tests of human performance.

Speculative parallelization of multipath radiosity algorithm

In computer graphics, global illumination algorithms take into account not only the light that comes directly from the sources, but also the light interreflections. This kind of algorithms produce very realistic images, but at a high computational cost, especially when dealing with complex environments. Parallel computation has been successfully applied to such algorithms in order to make it possible to compute highly-realistic images in a reasonable time. We introduce here a speculation-based parallel solution for a global illumination algorithm in the context of radiosity, in which we have taken advantage of the hierarchical nature of such an algorithm

Validación lingüística y psicométrica (adaptación cultural) de la escala Plutss para disfunción del tracto urinario inferior en niños colombianos

80% de los niños con ITU recurrente tiene algún síntoma de disfunción del tracto urinario inferior. Estos síntomas se clasifican según la ICCS (International Childrens Continence Society) de acuerdo a la fase del funcionamiento de la vejiga en la que presenten alteración, están los síntomas de llenado, los de eliminación y los asociados. Caracterizar estos síntomas, en forma objetiva para que no fueran simples relatos descriptivos de quejas de pacientes y pudieran ser utilizados para hacer diagnóstico y monitorear tratamiento obligó al uso de escalas que puntuaran cada uno de ellos. Estas escalas tienen su origen en el concepto del I-PSS (Puntaje Internacional de los Síntomas Prostáticos) que es una herramienta de gran utilidad para la clasificación de la hipertrofia prostática Hoy en día hay tres herramientas validadas para evaluar las alteraciones del tracto urinario inferior en niños; sin embargo ninguna de ellas ha sido a sido traducida al español ni adaptada culturalmente a la población hispanoamericana. El objetivo de este estudio es realizar la adaptación cultural (validación lingüística y psicométrica) de la escala PLUTSS,(4) que ya esta validada y es ampliamente utilizada; para aplicarla en un grupo de niños Colombianos estableciendo así el comportamiento de estos síntomas en nuestra población y para que pueda ser utilizada como herramienta de diagnóstico y seguimiento en los niños con alteración del tracto urinario inferior

Prácticas de recursos humanos y su relación con el engagement de los empleados en una Institución de Educación Superior en la ciudad de Bogotá Colombia

Es importante el estudio de las PRH y su relación con el engagement, para la toma de decisiones sobre el recurso humano, de tal forma que el propósito de esta investigación fue describir la relación entre las PRH y el engagement en una Institución de Educación Superior – IES de Bogotá, para ello se llevó a cabo una investigación con 72 colaboradores tanto administrativos como académicos. La escala de medida utilizada en este estudio tiene en cuenta los siguientes factores de las PRH: selección, promoción, formación, evaluación de desempeño, compensación y balance trabajo / familia y los factores analizados de la escala de medida para el engagement son vigor, dedicación y absorción. Los datos después de ser obtenidos, fueron procesados a través del Statical Package for Social Sciences (SPSS). Los datos fueron analizados, con base en los argumentos conceptuales y antecedentes que justifican dicha investigación, generando los resultados que contribuyeron a validar la hipótesis y objetivos planteados, con estadísticos básicos de correlación y regresiones para determinar el poder predictivo de una variable sobre la otra. Los resultados obtenidos en términos generales demuestran que las PRH tienen un efecto significativo en el engagement aunque de manera diferenciada.

Valores de trabalho, satisfação global com o trabalho e satisfação com a vida : um estudo exploratório das diferenças sócio-demográficas em institutos de saúde

Foram objetivos do presente estudo proceder à análise das relações entre Valores de trabalho, Satisfação no trabalho e Satisfação com a vida em profissionais do sector da saúde e perceber se dimensões como antiguidade na empresa, os anos de experiência e o número de organizações, função, definição de objetivos, avaliação do desempenho, idade, escolaridade, sexo e estado civil tinham um papel nas dimensões principais do estudo. Foi recolhida uma amostra de 214 profissionais da saúde, sendo 24% do sexo masculino e com idades entre 21 e 71 anos (M=40.06; DP=10.93). Foram utilizados os instrumentos WVS (Schwartz, 1994), QSGT (Hackman & Oldham, 1975) e SWLS (Diener, 1984). Os resultados mostraram que existe uma relação positiva entre a satisfação na vida e a satisfação no trabalho; que quanto mais elevados eram os valores de trabalho Poder, Realização, Hedonismo, Estimulação, Auto direção, Benevolência, Conformismo e Segurança, maior era a Satisfação no trabalho; que quanto mais elevados são os valores de trabalho Poder, Realização, Hedonismo, Estimulação, Auto direção, Universalismo, Benevolência, Tradição, Conformismo e Segurança maior era a Satisfação com a vida; e que existem diferenças entre sexos, idade, estado civil e escolaridade ao nível dos valores de trabalho. Contudo, apesar da satisfação com a vida ser influenciada pela satisfação no trabalho e pelos valores de trabalho, estas dimensões, por si só, não explicam fortemente a satisfação com a vida.

Museums and quality, from the concept of the museum that carries out functions to the museum that provides services

Quality management Self-evaluation of the organisation Citizens/customers satisfaction Impact on society evaluation Key performance evaluation Good practices comparison (Benchmarking) Continuous improvement In professional environments, when quality assessment of museums is discussed, one immediately thinks of the honourableness of the directors and curators, the erudition and specialisation of knowledge, the diversity of the gathered material and study of the collections, the collections conservation methods and environmental control, the regularity and notoriety of the exhibitions and artists, the building’s architecture and site, the recreation of environments, the museographic equipment design. We admit that the roles and attributes listed above can contribute to the definition of a specificity of museological good practice within a hierarchised functional perspective (the museum functions) and for the classification of museums according to a scale, validated between peers, based on “installed” appreciation criteria, enforced from above downwards, according to the “prestige” of the products and of those who conceive them, but that say nothing about the effective satisfaction of the citizen/customers and the real impact on society. There is a lack of evaluation instruments that would give us a return of all that the museum is and represents in contemporary society, focused on being and on the relation with the other, in detriment of the ostentatious possession and of the doing in order to meet one’s duties. But it is only possible to evaluate something by measurement and comparison, on the basis of well defined criteria, from a common grid, implicating all of the actors in the self-evaluation, in the definition of the aims to fulfil and in the obtaining of results.

A satisfação com a avaliação de desempenho e o comprometimento afectivo

A presente investigação incide no estudo da Satisfação com a Avaliação de Desempenho e o Comprometimento Afectivo. A Avaliação de Desempenho é um tema actual e que tem vindo a ser bastante investigado considerando que oferece às empresas instrumentos que medem a relação dos colaboradores com a sua função. Segundo pesquisas recentes existe uma importante relação entre a Satisfação com a Avaliação de Desempenho e o Comprometimento Afectivo (Kuuvas, 2006; Vignaswaran,2005; Cook & Crossman, 2005). Os resultados obtidos na análise das hipóteses colocadas permitiram identificar a existência de uma influência significativa entre a Satisfação com a Avaliação de Desempenho e o Comprometimento Afectivo. Na Satisfação com o Chefe foram identificadas relações com a Satisfação com a Avaliação de Desempenho e com o Comprometimento Afectivo. Na Satisfação com a Avaliação de Desempenho foi identificada uma relação de influência com o Desempenho. Por último, foi estabelecido uma relação significativa entre a Satisfação com o Chefe e o Desempenho mediada pela Satisfação com a Avaliação de Desempenho. Os resultados levaram à confirmação do modelo em análise, estando este linha com o quadro teórico estabelecido. Foram discutidos algumas das implicações dos resultados obtidos e sugestões futuras.

Improved and optimal dual circular 32-QAM for MB-OFDM

Quadrature Phase Shift Keying (QPSK) and Dual Carrier Modulation (DCM) are currently used as the modulation schemes for Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the ECMA-368 defined Ultra-Wideband (UWB) radio platform. ECMA-368 has been chosen as the physical radio platform for many systems including Wireless USB (W-USB), Bluetooth 3.0 and Wireless HDMI; hence ECMA-368 is an important issue to consumer electronics and the users’ experience of these products. To enable the transport of high-rate USB, ECMA-368 offers up to 480 Mb/s instantaneous bit rate to the Medium Access Control (MAC) layer, but depending on radio channel conditions dropped packets unfortunately result in a lower throughput. This paper presents improvement on a high data rate modulation scheme that fits within the configuration of the current standard increasing system throughput by achieving 600 Mb/s (reliable to 3.2 meters) thus maintaining the high rate USB throughput even with a moderate level of dropped packets. The modulation system is termed improved and optimal Dual Circular 32-QAM (DC 32-QAM). The system performance for improved and optimal DC 32-QAM modulation is presented and compared with previous DC 32- QAM, 16-QAM and DCM.

Bode's maximum available feedback and phase margin

'Maximum Available Feedback' is Bode's term for the highest possible loop gain over a given bandwidth, with specified stability margins, in a single loop feedback system. His work using asymptotic analysis allowed Bode to develop a methodology for achieving this. However, the actual system performance differs from that specified, due to the use of asymptotic approximations, and the author[2] has described how, for instance, the actual phase margin is often much lower than required when the bandwidth is high, and proposed novel modifications to the asymptotes to address the issue. This paper gives some new analysis of such systems, showing that the method also contravenes Bode's definition of phase margin, and shows how the author's modifications can be used for different amounts of bandwidth.

Improved channel estimation in TDMA by reproduction with applications in GSM/GPRS under co-channel interference

Finding an estimate of the channel impulse response (CIR) by correlating a received known (training) sequence with the sent training sequence is commonplace. Where required, it is also common to truncate the longer correlation to a sub-set of correlation coefficients by finding the set of N sequential correlation coefficients with the maximum power. This paper presents a new approach to selecting the optimal set of N CIR coefficients from the correlation rather than relying on power. The algorithm reconstructs a set of predicted symbols using the training sequence and various sub-sets of the correlation to find the sub-set that results in the minimum mean squared error between the actual received symbols and the reconstructed symbols. The application of the algorithm is presented in the context of the TDMA based GSM/GPRS system to demonstrate an improvement in the system performance with the new algorithm and the results are presented in the paper. However, the application lends itself to any training sequence based communication system often found within wireless consumer electronic device(1).

Robust background model for pixel based people counting using a single uncalibrated camera

Several pixel-based people counting methods have been developed over the years. Among these the product of scale-weighted pixel sums and a linear correlation coefficient is a popular people counting approach. However most approaches have paid little attention to resolving the true background and instead take all foreground pixels into account. With large crowds moving at varying speeds and with the presence of other moving objects such as vehicles this approach is prone to problems. In this paper we present a method which concentrates on determining the true-foreground, i.e. human-image pixels only. To do this we have proposed, implemented and comparatively evaluated a human detection layer to make people counting more robust in the presence of noise and lack of empty background sequences. We show the effect of combining human detection with a pixel-map based algorithm to i) count only human-classified pixels and ii) prevent foreground pixels belonging to humans from being absorbed into the background model. We evaluate the performance of this approach on the PETS 2009 dataset using various configurations of the proposed methods. Our evaluation demonstrates that the basic benchmark method we implemented can achieve an accuracy of up to 87% on sequence ¿S1.L1 13-57 View 001¿ and our proposed approach can achieve up to 82% on sequence ¿S1.L3 14-33 View 001¿ where the crowd stops and the benchmark accuracy falls to 64%.

PETS2009: dataset and challenge

This paper describes the crowd image analysis challenge that forms part of the PETS 2009 workshop. The aim of this challenge is to use new or existing systems for i) crowd count and density estimation, ii) tracking of individual(s) within a crowd, and iii) detection of separate flows and specific crowd events, in a real-world environment. The dataset scenarios were filmed from multiple cameras and involve multiple actors.

An overview of the PETS 2009 challenge

This paper describes the crowd image analysis challenge that forms part of the PETS 2009 workshop. The aim of this challenge is to use new or existing systems for i) crowd count and density estimation, ii) tracking of individual(s) within a crowd, and iii) detection of separate flows and specific crowd events, in a real-world environment. The dataset scenarios were filmed from multiple cameras and involve multiple actors.

Dual carrier modulation demapping methods and performances for wireless USB

Dual Carrier Modulation (DCM) was chosen as the higher data rate modulation scheme for MB-OFDM (Multiband Orthogonal Frequency Division Multiplexing) in the UWB (Ultra-Wide Band) radio platform ECMA-368. ECMA-368 has been chosen as the physical implementation for high data rate Wireless USB (W-USB) and Bluetooth 3.0. In this paper, different demapping methods for the DCM demapper are presented, being Soft Bit, Maximum Likely (ML) Soft Bit and Log Likelihood Ratio (LLR). Frequency diversity and Channel State Information (CSI) are further techniques to enhance demapping methods. The system performance for those DCM demapping methods simulated in realistic multi-path environments are provided and compared.