En santé, le besoin de quantifier des phénomènes subjectifs a émergé au cours du dernier siècle avec par exemple, l'évaluation de la qualité de vie (QdV), de la fatigue ou de l'anxiété. L'intérêt croissant face à ces mesures de santé perçue appelées "Patient-Reported Outcomes" (PRO) apparaît notamment dans les maladies chroniques. Afin de pouvoir analyser l'évolution de la QdV des patients ou d'autres types de PRO au fil du temps, des données longitudinales sont collectées.Ces données issues de PRO sont difficiles à appréhender car les patients peuvent percevoir et interpréter différemment les questions qui leur sont posées au cours du temps selon l’évolution de leur maladie, en termes de signification, priorités et retentissement sur leur vie personnelle. Ce phénomène, appelé « response shift » (RS), est souvent lié à la façon dont les patients s’adaptent à leur maladie. En présence de RS, les évolutions observées des patients peuvent ne pas refléter correctement les véritables changements ressentis par ceux-ci. L’objectif de ce travail porte sur le développement et l’évaluation de deux approches l’une, basée sur les modèles à équations structurelles (SEM) et l’autre, sur la théorie de réponse à l’item (IRT), avec l’originalité de travailler au niveau de l’item. Ces méthodes permettent la détection et l'estimation du RS ainsi que sa prise en compte lors d’analyses.Les performances des approches ont été évaluées en les appliquant sur des données réelles mais également au moyen d'études de simulations. Les résultats obtenus grâce aux simulations permettent de mieux identifier quelle approche méthodologique adopter selon les contextes. Les avantages et inconvénients de l'utilisation de chacune des méthodes, sont soulignés et des recommandations ont été proposées. / During the last century, many studies in health attempt to measure important characteristics, such as Health Related Quality of Life (QoL) using Patient-reported outcomes (PRO). QoL and other perceived health measures (pain, fatigue, etc.) are increasingly used in chronic diseases. In order to analyse the evolution of patients’ QoL or other types of PRO over time, longitudinal data are collected.These PRO data are difficult to interpret due to the patients’ changing in the standards, values, or conceptualization of what the PRO is intended to measure (eg: QoL). This phenomenon is referred to as “response shift” (RS) and is often linked to the way the patients might adapt or cope with their disease experience. As a consequence of RS, observed patient’s evolutions may thus not properly reflect true perceived health changes.The objective of this work is to develop and assess two approaches at item level, one, based on structural equation modelling (SEM) and other, on item response theory (IRT). These statistical approaches are currently used for RS analysis on PRO data. Both the identification of RS occurrence and its appropriate adjustment in the analyses of longitudinal PRO data are studied.The performance of IRT and SEM were assessed by applying them on real data and through simulations studies. The results obtained in the simulation allow choosing which methodological approach should be applied according to the context.The pros and cons of using one method or another as well as the potential of using both of them as complementary analyses providing different insights into the field of response shift are be underlined.

The 2-norbornyl cation is an old topic in physical-organic chemistry. Whether in classical or non-classical form (partial bridged form) it has been one of the focus of discussion. Currently the experimental data and theoretical calculations favorably support the idea that 2-norbornyl cation is not in the classical form in the stable-ion condition. In this paper, first, we will show that a 3-center-2-electron π-complex is formed by the collapse of 2-norbornyl cation. Further, using different theoretical methods (B3LYP, MP2) with different basis sets (6-31+G, 6-31G(d, p), 6-311G(d, p), 6-311G(2d, p)), we find that there is a trend for the 3-center-2-electron π-complex to approach the Cs symmetry, and this π-complex oscillates within the numerical limits of the perfect Cs symmetrical configuration. The stabilization energies of the π-complex are 13.87 Kcal/mol and 19.47 Kcal/mol by B3LYP/6-31+G and MP2/6-31+G, respectively. Second, our calculations also show that the transition state between 2-norbornyl cation and 3-norbornyl cation is formed by a 3, 2-proton shift, not the generally accepted 3, 2-hydride shift. The activation energy of this 3, 2-proton shift is 10.9 Kcal/mol. Detailed structural changes in the optimization process and the formation of transition state (also a 3-center-2-electron π-complex) between 2-norbornyl cation and 3-norbornyl cation will also be included.

No description available.

No description available.

Un automate cellulaire est un système dynamique discret qui modélise des objets ayant une évolution parallèle synchrone: l'espace est divisé en cellules ayant chacune un état et qui évoluent toutes selon une même règle locale, qui ne dépend que d'un nombre fini de cellules voisines. Malgré la simplicité de la formalisation de ce système, des comportements très complexes peuvent apparaître, qui en font notamment un modèle de calcul. Cette complexité a été rattachée à diverses théories: topologie, mesure, décidabilité, information...Nous adoptons ici une approche basée sur la dynamique symbolique, c'est à dire l'étude des mots infinis sur un alphabet donné auxquels on applique un décalage, suppression de la première lettre. À chaque automate cellulaire peut en effet être associé son tracé, l'ensemble des mots infinis représentant la séquence des états successifs pris par la cellule centrale de l'espace - ou un groupe de cellules centrales. On a alors une factorisation topologique: la lecture d'une lettre dans un de ces mots correspond exactement à une étape de l'évolution de l'automate. De nombreuses propriétés topologiques sont alors transmises par cette factorisation. Inversement, le fait que les cellules évoluent toutes de la même manière permet de déduire certaines propriétés de l'automate à partir de celles de son tracé. La première partie de la thèse est consacrée à ces nombreux liens. Une deuxième partie présente des conditions suffisantes pour qu'un ensemble de mots infinis soit le tracé d'un automate cellulaire. Enfin, une troisième partie donne un point de vue plus informatique, en récapitulant les principaux résultats d'indécidabilité sur le sujet et en prouvant que toutes les propriétés du tracé qui peuvent se voir infiniment tard sont indécidables / A cellular automaton is a discrete dynamical system which can model objects that evolve parallelly and asynchronously : the space is divided into cells, each of which has a state evolving according to some single local rule and a finite number of neighboring cells. Though this system can easily be formalized, very complex behaviors can appear ; it turns out to be a powerful computational model. That complexity can be studied with respect to various theories : topology, measure, decidability, information...We adopt here an approach bases on symbolic dynamics, linked to the topology and to the study of shifts of infinite words (suppression of their first letter). To each cellular automaton can be associated its trace subshift, the set of infinite words that represent the sequence of successive states taken by the central cell or some group of central cells. We then have a topological factorisation : reading a letter in one of these words correspond to applying a step of evolution of the automaton

MA (Social Work), Faculty of Humanities, University of the Witwatersrand, 1995

In modern communication systems, the rate of transmitted data is growing rapidly. This leads to the need for more sophisticated methods and techniques of implementation in every block of the transmitter-receiver chain. The weakest link in radio communications is the transmission channel. The signal, which is passed through it, suffers from many degrading factors like noise, attenuation, diffraction, scattering etc. In the receiver side, the modulated signal has to be restored to its initial state in order to extract the useful information. Assuming that the channel acts like a filter with finite impulse, one has to know its coefficients in order to apply the inverse function, which will restore the signal back to its initial state. The techniques which deal with this problem are called channel estimation. Noise is one of the causes that degrade the quality of the received signal. If it could be discarded, then the process of channel estimation would be easier. Transmitting special symbols, called pilots with known amplitude, phase and position to the receiver and assuming that the noise has zero mean, an averaging process could reduce the noise impact to the pilot amplitudes and thus simplify the channel estimation process. In this thesis, a novel channel estimation method based on noise rejection is introduced. The estimator takes into account the time variations of the channel and adapts its buffer size in order to achieve the best performance. Many configurations of the estimator were tested and at the beginning of the research fixed size estimators were tested. The fixed estimator has a very good performance for channels which could be considered as stationary in the time domain, like Additive White Gaussian Noise (AWGN) channels or slowly time-varying channels. AWGN channel is a channel model where the only distorting factor is the noise, where noise is every unwanted signal interfering with the useful signal. The properties of the noise are that it is additive, which means that the noise is superimposed on the transmitted signal, it is white so the power density is constant for all frequencies, and it has a Gaussian distribution in the time domain with zero mean and variance σ2=N. A slowly time varying channel refers to channel with coherence time larger than the transmitted symbol duration. The performance of a fixed size averaging estimator in case of fast time-varying channels is subject to the buffering time. When the buffering time is smaller or equal to a portion of the coherence time the averaging process offers better performance than the conventional estimation, but when the buffering time exceeds this portion of the coherence time the performance of the averaging process degrades fast. So, an extension has been made to the averaging estimator that estimates the Doppler shift and thus the coherence time, where the channel could be assumed as stationary. The improved estimator called Adaptive Averaging Channel Estimator (AACE) is capable to adjust its buffer size and thus to average only successive Orthogonal Frequency Division Multiplexing (OFDM) symbols that have the same channel distortions. The OFDM is a transmission method where instead of transmitting the data stream using only on carrier, the stream is divided into parallel sub-streams where the subcarriers conveying the sub-streams are orthogonal to each other. The use of the OFDM increases the symbol duration making it more robust against Inter-Symbol Interference (ISI), which the interference among successive transmitted symbols, and also divides the channel bandwidth into small sub-bandwidths preventing frequency selectivity because of the multipath nature of the radio channel. Simulations using the Rayleigh channel model were performed and the results clearly demonstrate the benefits of the AACE in the channel estimation process. The performance of the combination of AACE with Least Square estimation (AACE-LS) is superior to the conventional Least Square estimation especially for low Doppler shifts and it is close to the Linear Minimum Mean Square Error (LMMSE) estimation performance. Consequently, if the receiver has low computational resources and/or the channel statistics are unknown, then the AACE-LS estimator is a valid choice for modern radio receivers. Moreover, the proposed adaptive averaging process could be used in any OFDM system based on pilot aided channel estimation. In order to verify the superiority of the AACE algorithm, quantitative results are provided in terms of BER vs SNR. It is demonstrated that AACE-LS is 7dB more sensitive than the LS estimator.

In this thesis, we combined inductively coupled plasma reactive ion etching (ICP-RIE) and SiO2 sputtering to enhance quantum well intermixing (QWI). The samples used in this study were grown by molecular beam epitaxy (MBE) and metal organic chemical vapor deposition (MOCVD) on InP substrates. MBE sample consists of three In0.53Ga0.47As quantum wells, and the other consists of three In0.77Ga0.23As0.79P0.21 quantum wells. Ar+ bombardment by ICP-RIE was the first process step, and then a 300 nm SiO2 capping layer was sputtered upon the samples. The processed samples were subject to rapid thermal annealing. The properties of quantum wells after annealing were determined by photoluminescence (PL) measurement. The In0.53Ga0.47As/In0.53Ga0.26Al0.21As structure was used to design a series of experiments. First, we observed that the amount of blueshift increased with ICP-RIE time increased. ICP-RIE for 8 minutes was the optimum resulting in a bandgap blueshift of 60 nm, leaving a distance of about 200 nm between QWs and the SiO2 interface. The PL blueshift was directly ascribed to QWI caused by compositional interdiffusion between QWs and barriers. To determine how ICP-RIE affects QWI, we used H3PO4 solution to etch samples to the depth that was around 200 nm away from the QWs, and then coated by a sputtered SiO2 layer. Under 700¢J annealing, it gave rise to a blueshift of only 18 nm. And we also proved that the sputtered SiO2 capping layer provided an extra amount of bandgap blueshift. After the mechanism of QWI combining ICP-RIE and SiO2 sputtering was established, we applied this QWI process in In0.77Ga0.23As0.79P0.21/In0.57Ga0.43As0.64P0.36 material system, and we obtained a maximum amount of blueshift of 90 nm in this study.

High technology business is the motive power of Taiwan¡¦s economic development. It creates the golden miracle of Taiwan¡¦s economic. IC industry and TFT LCD are the main force in Taiwan. Manufacture is core of these businesses. In-line operators are the fundamental of these businesses. [Four shift Two round] is the working style of these companies. It is different from the traditional industry in Taiwan. IC industries face the different labor power problem from highly growth status to mature status. The biggest change is they can't replace the new employee easily from the job market. Especially TFT industry joining, the replacement is higher in the labor power parts. It has already impacted IC industry. Mature labors select to quit and new employees are hardly to recruit. This situation made IC industry need to review their strategies of labor power maintenance. It is the most important part for each IC manufacturing company to recruit suitable new employees and keep the mature labor power. Labor power maintenance is not only the duty of human resource department. It needs to be aligned with the core value of the whole business. Concentrate the common consensus of all members and provide the labor power policy to correspond with current environment. This study is through the quit analysis and investigate to analyze the working status and system of the operators of [Four shift Two round]. Hope to provide the conclusion and suggestion for related businesses.

Precision measurement technologies have been developed for a long time. Measuring the displacement of meso-scale objects became an important issue in the recent years. In this study, a displacement measurement system for meso-scale objects is developed by combining the measurement technique of using position sensing detectors (PSD) and the grinding skill of fabricating micro scale reflection surfaces on optical fiber tips. This measurement system can be used for detecting the postweld shift (PWS) of a laser-welded butterfly-type laser diode module package. The PWS affects the coupling efficiency of a laser-welded butterfly-type laser diode module package quite a lot. Although there are many papers studied the measurement of PWS, most of the measurements are less than 6 degrees of freedom (DOF). The system developed in this paper can measure the 6 DOF displacement of the PWS. An attachment for carrying 3 micro reflection probes is designed firstly which will be settled on the fiber ferrule of a laser diode module. After all the coordinate transformation matrices of the laser beam light source, micro reflection surfaces, and the position sensing detectors are derived as well as the PSD readings are taken, displacements of the ferrule of a laser diode module can be solved from the displacement equations by using numerical method. The system developed in this paper is implemented on a Newport butterfly-type laser diode module package station (Model LW4200) for demonstration. The testing results show that the resolution of this system is 1£gm and the accuracy is 2£gm. Beside the application of measuring the 6 degrees of freedom PWS of a laser diode module package, the system developed in this paper can also be applied for measurement the displacement of other meso-scale objects.