Successful organizational change experience can be easily copied by another organization in the same culture. Residence Administration (R.A.) in Taiwan had a wonderful change experience that can be learned by another public organizations in Taiwan. This paper used Sastry¡¦s(1997) organizational change theory and dynamic feedback loops to research the R.A.¡¦ successful change stories and compare with one health organization for deeper understanding. We know successful change is a dynamic structure, and found some helpful strategies for successful public organizational change: 1. Organizational performance was being influenced by two loops, strategy appropriateness loop and competence establishment loop. 2. Strategy appropriateness loop shows that frequently changing organizational main strategies would lead to bad organizational performance. 3. Competence establisyhment loop shows that there must be enough time to establish new competence for performing new strategies. 4. Change ability loop shows that higher organizational inertia led to lower organizational ability to adapt to its environment. 5. Inertia created loop shows that organizational inertia is highly related to its socialized process. According to the dynamic feedback loops, one organization could figure out its present situation and think its change strategies. This paper showed that Sastry¡¦s theory could explain the R.A.¡¦s change strategies well. Other public organizations can use R.A.¡¦s experience to make their own successful change stories.

Many mechanical systems exhibit nonlinear movement and are subject to perturbations from a desired equilibrium state. These perturbations can greatly reduce the efficiency of the systems. It is therefore desirous to analyze the asymptotic stabilizability of an equilibrium solution of nonlinear systems; an excellent method of performing these analyses is through study of Jacobian linearization's and their properties. Two enlightening examples of nonlinear mechanical systems are the Simple Inverted Pendulum and the Inverted Pendulum on a Cart (PoC). These examples provide insight into both the feasibility and usability of Jacobian linearizations of nonlinear systems, as well as demonstrate the concepts of local stability, observability, controllability and detectability of linearized systems under varying parameters. Some examples of constant disturbances and effects are considered. The ultimate goal is to examine stabilizability, through both static and dynamic feedback controllers, of mechanical systems

Cette thèse traite du problème de la stabilisation d'un système de lancement aéroporté (éventuellement non habité) pour satellites. Le lancement aéroporté consiste à ramener, à l'aide d'un avion, un satellite et son lanceur (fusée) à une certaine hauteur, et d'exécuter son lancement dans les airs (souvent en larguant la fusée). Ceci est similaire au lancement d'un missile par un avion chasseur. La plus grande différence réside dans le rapport de masse entre l'avion et le lanceur qui est beaucoup plus proche de l'unité (fusée lourde comparée à la masse de l'avion). Le système est composé de deux étages: le premier étage est dit avion porteur qui est un véhicule aérien automatisé. Il porte le lanceur qui constitue le deuxième étage (la fusée). Dans la première partie, sont proposées des approches de modélisation pour le système de largage pendant et après le largage. La première approche considère que la phase de séparation est instantanée, mais imparfaite. Par conséquent le système est vu comme un modèle d'aéroplane dont les variables d'état sont avec des larges conditions initiales dues à la séparation imparfaite. Une deuxième approche considère la séparation elle-même, représentée par une forte perturbation (un extrême cas) sur les forces et couples aérodynamiques du modèle au cours d'un intervalle de temps. Dans la deuxième partie, afin de stabiliser le système de largage après la séparation, la commande à intégrateur conditionnel modifié est développée dans un premier temps pour une classe des systèmes non-linéaires multi-entrées multi-sorties, avec comme point de départ la théorie introduite par Khalil et co-auteurs pour des systèmes mono entrée mono sortie. Cette commande a été ensuite étendue pour la commande à servo-compensateur conditionnel modifié pour une classe de systèmes non-linéaires multi-entrées multi-sorties. Les deux stratégies ont été appliquées pour stabiliser le système de largage pendant et après la phase de séparation. Ces techniques ont l'avantage d'être robustes et de pouvoir utiliser des modèles approximatifs. D'un autre côté, il était important d'examiner la possibilité d'obtenir de meilleures performances en utilisant de meilleurs modèles. Pour cette raison, la commande de linéarisation par bouclage dynamique a été étudiée. Finalement, les performances de toutes ces méthodes de commande (ainsi que certaines commandes de base additionnelles) ont été illustrées par des simulations sous Matlab/Simulink sur un modèle non-linéaire de F-16. / This thesis addresses the problem of the stabilization of an (unmanned) airlaunch system. Air launching consists in bringing a satellite and its launcher (rocket) to a certain height using an aircraft, and then launching it from the air (often by dropping the rocket), in a similar way of launching a missile from a fighter. The main difference is that the envisaged mass ratio is much closer to one (heavy rocket compared to aircraft mass). It is then composed of two stages: the first stage called carrier aircraft consists of an <unmanned> aerial vehicle that carries the launcher which constitutes the second stage (rocket). This thesis starts by introducing the problem and objectives, continues by presenting several approaches to model the airlaunch system, and ends by developing different advanced control methods to stabilize it after the launching phase. In the modeling part we propose a firstly approach called the initial condition model which assumes that the separation phase is instantaneous, and then the airlaunch system is composed of an aircraft model after the launching phase but with large initial conditions on its state variables, caused by a non-perfect split phase. A second approach assumes that the separation phase itself is modeled by a disturbance on aerodynamic forces and moments (from a worst case) during a time interval. In the control part a modified conditional integrator controller for a class of nonlinear multi-input multi-output systems is first developed starting from the conditional integrator theory developed by Khalil and co-workers. It is then extended to a modified conditional servocompensator control for a class of nonlinear multi-input multi-output systems. Both control strategies were then applied to stabilize the airlaunch system after the separation phase. They have the advantage of being very robust, and they don't depend so much on reliable models. Even if these control strategies gave good results, it was investigated in this thesis another control approach much more dependent on detailed and reliable models. This approach was based on dynamic feedback linearization theory, and the main idea is to obtain better performance in trade off better models. Finally, all proposed control methods (plus some standard ones) were compared and illustrated by simulations under Matlab/Simulink on a nonlinear F-16 model. These simulations have shown that the results were as expected, and that each control strategy was well fit for a particular situation.

Neste trabalho, consideramos o problema de desacoplamento de perturbações por realimentação dinâmica regular do estado para sistemas não lineares afins. Utilizando a abordagem geométrica-diferencial, estabelecemos condições necessárias e suficientes de solução de tal problema. Mostramos que tais condições são baseadas na geometria de um sistema estendido, obtido pela colocação de integradores em série com as entradas do sistema original. Quando tal problema e solúvel, mostramos também que o algoritmo de extensão dinâmica permite a construção do compensador solução. Como um subproduto de tais técnicas, obtemos uma forma geométrica de determinação da estrutura algébrica no infinito, através da geometria do sistema estendido. / In this work we consider the Problem of Disturbance Decoupling by Regular Dynamic Feedback for the class of affine nonlinear systems. We use the so-called Differential Geometric Approach to derive the necessary and sufficient conditions for this problem\'s solution. We show that the solvability of this problem is governed by the geometry of an Extended System obtained by putting integrators in series with the inputs of the original system. When the necessary conditions are satisfied, we show that the well known dynamic extension algorithm can be used to construct a solution. We also show that the algebraic structure at infinity can be computed by geometric methods with the aid of the Extended System.

Neste trabalho, consideramos o problema de desacoplamento de perturbações por realimentação dinâmica regular do estado para sistemas não lineares afins. Utilizando a abordagem geométrica-diferencial, estabelecemos condições necessárias e suficientes de solução de tal problema. Mostramos que tais condições são baseadas na geometria de um sistema estendido, obtido pela colocação de integradores em série com as entradas do sistema original. Quando tal problema e solúvel, mostramos também que o algoritmo de extensão dinâmica permite a construção do compensador solução. Como um subproduto de tais técnicas, obtemos uma forma geométrica de determinação da estrutura algébrica no infinito, através da geometria do sistema estendido. / In this work we consider the Problem of Disturbance Decoupling by Regular Dynamic Feedback for the class of affine nonlinear systems. We use the so-called Differential Geometric Approach to derive the necessary and sufficient conditions for this problem\'s solution. We show that the solvability of this problem is governed by the geometry of an Extended System obtained by putting integrators in series with the inputs of the original system. When the necessary conditions are satisfied, we show that the well known dynamic extension algorithm can be used to construct a solution. We also show that the algebraic structure at infinity can be computed by geometric methods with the aid of the Extended System.

In this thesis, the tonal noise produced by flow over perforated plates at oblique angles of incidence is studied experimentally. A two-dimensional model of a perforated plate is used, where the circular holes of a typical perforated plate are replaced by a series of long rectangular Aluminum slats with an adjustable gap width between them. The slats are 3.175 mm thick and the gap width between them is set to 3.175 mm, 6.35 mm, and 12.7 mm. This simplified model is mounted at the exit of an open-loop wind tunnel and tested at angles of incidence of 0° to 40° and flow velocities of 0 to 30 m/s. An angle of 0° is defined as flow parallel to the plate. The acoustic response is studied using microphone measurements, and flow visualization is done using particle image velocimetry. The effect of the angle of incidence, flow velocity, gap width, and streamwise position are investigated. The flow visualization reveals that tonal noise is produced by the periodic shedding and impingement of vortices at the trailing edge of the gaps. Vortices form in the unstable free shear layer originating at the leading edge of the gap and impinge on the downstream side of the gap. At the downstream corner, these vortices separate into vortex pairs, consisting of one positively rotating and one negatively rotating vortex. These vortices are shed periodically, leading to the production of tonal noise at the shedding frequency. The effect of the angle of incidence is investigated by changing the angle of the plate with respect to the flow. For a given gap width, tones are produced only for a specific range of angles. Depending on the plate geometry, this range of angles is typically around 5° to 30°. Within this range of angles, the free shear layer impinges on the downstream side of the gap. For angles which are too small or too large, the free shear layer misses this downstream side and tones are not produced. For a larger gap width, tones are produced at smaller angles of incidence. Similarly, for a given plate geometry, there is a preferred range of flow velocities at which tonal noise is produced. The velocity at which the free shear layer is the most unstable at the tone frequency produces the strongest vortices and the loudest tones. The optimal velocity is lower for larger gap widths. Finally, it is found that the magnitude of the produced tones increases in the streamwise direction over repeated gaps along the length of the plate. This is due to the local flow conditions changing in the streamwise direction, only reaching the optimal conditions after a certain length of the plate. / Thesis / Master of Applied Science (MASc)

With the rise of English as the go-to language in the world, it has also become an important subject in the Swedish education system, aimed at preparing students for the English requirements expected of them in higher education and business. However, communication and content have become the main focus in the classroom, with grammar and accuracy being judged as variably important from teacher to teacher. This has led to students feeling confident in speaking, but lacking the skills needed to create accurate and coherent texts, the effects of which are detrimental to their credibility and can have serious negative effects in the workplace. The aim of this paper is to investigate the efficacy of different methods of corrective feedback (CF) aimed at improving grammatical accuracy in student writing. Eight studies were selected, looking at different methods of CF. The results showed that CF is indeed effective, but that many factors such as language proficiency, previous experience, scope of CF and error type influence the outcome of the CF. The implications of this are very relevant to the English classroom in Sweden as the classroom is not homogenous and teachers must take care to become aware of each student’s individual needs, prior knowledge and preferences in order to maximize the effectiveness of the CF. Future research could explore the effects of Dynamic CF and peer-reviewing, providing students with many opportunities to write and revise short texts while simultaneously actively engaging with language form.

Dans cette étude on s'intéresse à la dynamique d'une classe de systèmes non-linéaires décrits par des équations aux dérivées partielles (EDP) du type hyperbolique. L'objectif de l'étude est de construire des lois de contrôle par feedback dynamique de la sortie afin de stabiliser le système autour d'un point d'équilibre d'une part, et, d'autre part, de réguler la sortie vers le point de consigne. Nous considérons la classe des systèmes gouvernés par des EDP quasi-linéaires du type hyperbolique à deux variables indépendantes (une variable temporelle et une variable spatiale). Pour le bien-posé du système dynamique non seulement l'état initial mais aussi certaines conditions frontières doivent être prescrites en cohérence avec les EDP. Nous supposons que l'observation et le contrôle sont ponctuels. Autrement dit l'action du contrôle intervient dans le système via les conditions frontières et l'observation est effectuée aux points de la frontière. Notre étude est motivée par l'observation que de nombreux processus physiques sont modélisés par ce type d'équations EDP. Nous citons, par exemple, des processus tels que flux trafique en transport, flux de gaz dans un réseau de pipeline, échangeurs thermiques en génie des procédés, équations de télégraphe dans des lignes de transmission, canaux d'irrigation en génie civil etc. Nous commençons l'étude par une EDP non-linéaire scalaire. Dans ce cas-là nous proposons un correcteur intégral stabilisant qui assure la régulation de la sortie avec l'erreur statique nulle. Nous prouvons la stabilisation locale du système non-linéaire par le correcteur intégral en construisant une fonctionnelle de Lyapunov appropriée. La conception des correcteurs proportionnels et intégraux (PI) que nous proposons est étendue dans un cadre de systèmes de deux EDP. Nous prouvons la stabilisation du système en boucle fermée à l'aide d'une nouvelle fonctionnelle de Lyapunov. La synthèse des correcteurs PI stabilisants se poursuit dans un cadre de réseaux formés d'un nombre fini de systèmes à deux EDP : réseau étoilé et réseau série en cascade. Les contrôles et les observations se trouvent localisés aux différents nœuds de connexion. Pour ces configurations nous présentons un ensemble de correcteurs PI stabilisants qui assurent la régulation vers le point de consigne. Les correcteurs PI que nous concevons sont validés par des simulations numériques à partir des modèles non-linéaires EDP. La contribution de la thèse, par rapport à la littérature existante, consiste en l'élaboration de nouvelles fonctionnelles de Lyapunov pour une classe de systèmes stabilisés par correcteur PI. En effet une grande quantité de résultats ont été obtenus sur la stabilisation des systèmes hyperboliques par feedback statique de la sortie. Toutefois il existe encore peu de résultats sur la stabilisation de ces systèmes par feedback dynamique de la sortie. L'étude de la thèse est consacrée sur l'élaboration des fonctionnelles de Lyapunov permettant d'obtenir des correcteurs PI stabilisants. L'approche de Lyapunov direct que nous avons proposée a pour l'avantage de permettre d'étudier la robustesse des lois de feedback de la sortie PI vis-à-vis de la non-linéarité. Une autre contribution de la thèse consiste en la construction des programmes de Malab permettant d'effectuer des simulations numériques pour la validation des correcteurs conçus. Pour la résolution numérique des EDP hyperboliques nous avons discrétisé nos systèmes par le schéma numérique de Preissmann. Nous avons chaque fois un système d'équations algébriques non-linéaires à résoudre de façon récurrente. L'apport des simulations numériques nous permet de mieux comprendre la méthodologie applicative de la théorie du contrôle en dimension infinie / In this study we are interested in the dynamics of a class of nonlinear systems described by partial differential equations (PDE) of the hyperbolic type. The aim of the study is to construct control laws by dynamic feedback of the output in order to stabilize the system around an equilibrium point on the one hand and to regulate the output to the set-point. We consider the class of systems governed by hyperbolic PDEs with two independent variables (one time variable and one spatial variable). For the well-posed dynamic system not only the initial state but also certain boundary conditions must be prescribed in coherence with the PDEs. We assume that observation and control are punctual. In other words, the action of the control intervenes in the system via the boundary conditions and the observation is carried out at the points of the border. Our study is motivated by the observation that many physical processes are modeled by this type of PDE equations. Examples include processes such as traffic flow in transportation, gas flows in a pipeline network, heat exchangers in process engineering, telegraph equations in transmission lines, civil engineering irrigation channels, to cite but a few.We begin the study with a scalar nonlinear PDE. In this case we propose a stabilizing integral controller which ensures the regulation of the output with zero static error. We prove the local stabilization of the nonlinear system by the integral controller by constructing an appropriate Lyapunov functional. The design of the proportional and integral (PI) controllers that we propose is extended in a framework of two PDE systems. We prove the stabilization of the closed-loop system with a new Lyapunov functional. The synthesis of stabilizing PI controllers is carried out in a framework of networks formed by a finite number of two PDE systems: star network and serial network in cascade. Controls and observations are located at the different connection nodes. For these configurations we present a set of stabilizing PI controllers that regulate the output to the set-point. The PI controllers that we design are validated by numerical simulations from the nonlinear PDE models. The contribution of the thesis compared to the existing literature consists in the development of new Lyapunov functionals for the class of systems looped by a PI controller. Indeed, a large number of results have been obtained from the stabilization of hyperbolic systems by static feedback of the output. However, there are still few results with the stabilization of these systems by the output dynamic feedback. The study of the thesis is devoted to the development of the Lyapunov functional to obtain stabilizing PI controllers. The direct Lyapunov approach that we have proposed has the advantage of allowing to study the robustness of the output dynamic feedback laws in the form of PI controllers with respect to the nonlinearity. Another contribution of the thesis consists of the Malab program construction allowing to carry out numerical simulations for the validation of the conceived controllers. For the numerical resolution of hyperbolic PDEs, we have discretized our systems using the Preissmann numerical scheme. Each time moment we have a system of non-linear algebraic equations to be solved in a recurring way. The contribution of numerical simulations allows us to better understand the application methodology of the infinite dimension control theory

To meet the exponentially increasing traffic data driven by the rapidly growing mobile subscriptions, both industry and academia are exploring the potential of a new genera- tion (5G) of wireless technologies. An important 5G goal is to achieve high data rate. Small cells with spectrum sharing and multiple-input multiple-output (MIMO) techniques are one of the most promising 5G technologies, since it enables to increase the aggregate data rate by improving the spectral efficiency, nodes density and transmission bandwidth, respectively. However, the increased interference in the densified networks will in return limit the achievable rate performance if not properly managed. The considered setup can be modeled as MIMO interference networks, which can be classified into the K-user MIMO interference channel (IC) and the K-cell MIMO interfering broadcast channel/multiple access channel (MIMO-IBC/IMAC) according to the number of mobile stations (MSs) simultaneously served by each base station (BS). The thesis considers two physical layer (PHY) resource allocation problems that deal with the interference for both models: 1) Pareto boundary computation for the achiev- able rate region in a K-user single-stream MIMO IC and 2) grouping-based interference alignment (GIA) with optimized IA-Cell assignment in a MIMO-IMAC under limited feedback. In each problem, the thesis seeks to provide a deeper understanding of the system and novel mathematical results, along with supporting numerical examples. Some of the main contributions can be summarized as follows. It is an open problem to compute the Pareto boundary of the achievable rate region for a K-user single-stream MIMO IC. The K-user single-stream MIMO IC models multiple transmitter-receiver pairs which operate over the same spectrum simultaneously. Each transmitter and each receiver is equipped with multiple antennas, and a single desired data stream is communicated in each transmitter-receiver link. The individual achievable rates of the K users form a K-dimensional achievable rate region. To find efficient operating points in the achievable rate region, the Pareto boundary computation problem, which can be formulated as a multi-objective optimization problem, needs to be solved. The thesis transforms the multi-objective optimization problem to two single-objective optimization problems–single constraint rate maximization problem and alternating rate profile optimization problem, based on the formulations of the ε-constraint optimization and the weighted Chebyshev optimization, respectively. The thesis proposes two alternating optimization algorithms to solve both single-objective optimization problems. The convergence of both algorithms is guaranteed. Also, a heuristic initialization scheme is provided for each algorithm to achieve a high-quality solution. By varying the weights in each single-objective optimization problem, numerical results show that both algorithms provide an inner bound very close to the Pareto boundary. Furthermore, the thesis also computes some key points exactly on the Pareto boundary in closed-form. A framework for interference alignment (IA) under limited feedback is proposed for a MIMO-IMAC. The MIMO-IMAC well matches the uplink scenario in cellular system, where multiple cells share their spectrum and operate simultaneously. In each cell, a BS receives the desired signals from multiple MSs within its own cell and each BS and each MS is equipped with multi-antenna. By allowing the inter-cell coordination, the thesis develops a distributed IA framework under limited feedback from three aspects: the GIA, the IA-Cell assignment and dynamic feedback bit allocation (DBA), respec- tively. Firstly, the thesis provides a complete study along with some new improvements of the GIA, which enables to compute the exact IA precoders in closed-form, based on local channel state information at the receiver (CSIR). Secondly, the concept of IA-Cell assignment is introduced and its effect on the achievable rate and degrees of freedom (DoF) performance is analyzed. Two distributed matching approaches and one centralized assignment approach are proposed to find a good IA-Cell assignment in three scenrios with different backhaul overhead. Thirdly, under limited feedback, the thesis derives an upper bound of the residual interference to noise ratio (RINR), formulates and solves a corresponding DBA problem. Finally, numerical results show that the proposed GIA with optimized IA-Cell assignment and the DBA greatly outperforms the traditional GIA algorithm.

To meet the exponentially increasing traffic data driven by the rapidly growing mobile subscriptions, both industry and academia are exploring the potential of a new genera- tion (5G) of wireless technologies. An important 5G goal is to achieve high data rate. Small cells with spectrum sharing and multiple-input multiple-output (MIMO) techniques are one of the most promising 5G technologies, since it enables to increase the aggregate data rate by improving the spectral efficiency, nodes density and transmission bandwidth, respectively. However, the increased interference in the densified networks will in return limit the achievable rate performance if not properly managed. The considered setup can be modeled as MIMO interference networks, which can be classified into the K-user MIMO interference channel (IC) and the K-cell MIMO interfering broadcast channel/multiple access channel (MIMO-IBC/IMAC) according to the number of mobile stations (MSs) simultaneously served by each base station (BS). The thesis considers two physical layer (PHY) resource allocation problems that deal with the interference for both models: 1) Pareto boundary computation for the achiev- able rate region in a K-user single-stream MIMO IC and 2) grouping-based interference alignment (GIA) with optimized IA-Cell assignment in a MIMO-IMAC under limited feedback. In each problem, the thesis seeks to provide a deeper understanding of the system and novel mathematical results, along with supporting numerical examples. Some of the main contributions can be summarized as follows. It is an open problem to compute the Pareto boundary of the achievable rate region for a K-user single-stream MIMO IC. The K-user single-stream MIMO IC models multiple transmitter-receiver pairs which operate over the same spectrum simultaneously. Each transmitter and each receiver is equipped with multiple antennas, and a single desired data stream is communicated in each transmitter-receiver link. The individual achievable rates of the K users form a K-dimensional achievable rate region. To find efficient operating points in the achievable rate region, the Pareto boundary computation problem, which can be formulated as a multi-objective optimization problem, needs to be solved. The thesis transforms the multi-objective optimization problem to two single-objective optimization problems–single constraint rate maximization problem and alternating rate profile optimization problem, based on the formulations of the ε-constraint optimization and the weighted Chebyshev optimization, respectively. The thesis proposes two alternating optimization algorithms to solve both single-objective optimization problems. The convergence of both algorithms is guaranteed. Also, a heuristic initialization scheme is provided for each algorithm to achieve a high-quality solution. By varying the weights in each single-objective optimization problem, numerical results show that both algorithms provide an inner bound very close to the Pareto boundary. Furthermore, the thesis also computes some key points exactly on the Pareto boundary in closed-form. A framework for interference alignment (IA) under limited feedback is proposed for a MIMO-IMAC. The MIMO-IMAC well matches the uplink scenario in cellular system, where multiple cells share their spectrum and operate simultaneously. In each cell, a BS receives the desired signals from multiple MSs within its own cell and each BS and each MS is equipped with multi-antenna. By allowing the inter-cell coordination, the thesis develops a distributed IA framework under limited feedback from three aspects: the GIA, the IA-Cell assignment and dynamic feedback bit allocation (DBA), respec- tively. Firstly, the thesis provides a complete study along with some new improvements of the GIA, which enables to compute the exact IA precoders in closed-form, based on local channel state information at the receiver (CSIR). Secondly, the concept of IA-Cell assignment is introduced and its effect on the achievable rate and degrees of freedom (DoF) performance is analyzed. Two distributed matching approaches and one centralized assignment approach are proposed to find a good IA-Cell assignment in three scenrios with different backhaul overhead. Thirdly, under limited feedback, the thesis derives an upper bound of the residual interference to noise ratio (RINR), formulates and solves a corresponding DBA problem. Finally, numerical results show that the proposed GIA with optimized IA-Cell assignment and the DBA greatly outperforms the traditional GIA algorithm.