Other than mobile hydraulics and high voltage switchgears, Bucher Hydraulics is also involved in the less-known area of hydraulic lifts. In fact, Bucher Hydraulics did invent the electronically controlled lift valve in the 1970s. Since then, Bucher Hydraulics developed a wide line of products for hydraulic elevators, such as valves and power units. In 2012, this valve family included various sizes, pressure ranges, systems with constant motor speeds, inverter-driven motors, energy-efficient solutions with hydraulic counterweight, as well as customized solutions. As the common principle, all these solutions apply an electronic closed-loop control that uses a volumetric flow sensor and a proportional actuator. Since 2012, Bucher Hydraulics is substituting this valve family with a new generation, the iValve. Every iValve uses several self-teaching algorithms to adapt to its environment. Their on-board and cabinet electronics control solenoid currents and measure flow, pressure, and temperature. These features enable the iValve to self-monitor, to adapt to operating parameters, and to analyze and log information about itself and the attached system. This report on a highly specialized product is meant to provide inspiring insights.

Recognizing activities in real-world videos is a difficult problem exacerbated by background clutter, changes in camera angle & zoom, occlusion and rapid camera movements. Large corpora of labeled videos can be used to train automated activity recognition systems, but this requires expensive human labor and time. This thesis explores how closed captions that naturally accompany many videos can act as weak supervision that allows automatically collecting 'labeled' data for activity recognition. We show that such an approach can improve activity retrieval in soccer videos. Our system requires no manual labeling of video clips and needs minimal human supervision. We also present a novel caption classifier that uses additional linguistic information to determine whether a specific comment refers to an ongoing activity. We demonstrate that combining linguistic analysis and automatically trained activity recognizers can significantly improve the precision of video retrieval. / text

Hypersonic inlet unstart remains a major technical obstacle in the successful implementation of hypersonic air-breathing propulsion systems such as ramjets and scramjets. Unstart occurs when combustor-induced pressure fluctuations lead to rapid expulsion of the shock system from the isolator, and is associated with loss of thrust. The research presented here attempts to mitigate this behavior through the design and implementation of a closed-loop control scheme that regulates shock location within a Mach 1.8 wind tunnel isolator test section. To localize the position of the shock within the isolator, a set of high frequency Kulite pressure transducers are used to measure the static pressure at various points along the wind tunnel test section. A novel Kalman filter based approach is utilized, which fuses the estimates from two distinct shock localization algorithms running at 250 Hz to determine the location of the shock in real time. The primary shock localization algorithm is a geometrical shock detection scheme that can estimate the position of the shock system even when it is located between pressure transducers. The second algorithm utilizes a sum-of-pressures technique that can be calibrated by the geometrical algorithm in real time. The closed-loop controller generates commands every 100 ms to actuate a motorized flap downstream of the test section in an effort to regulate the shock to the desired location. The closed-loop control implementation utilized a simple logic-based controller as well as a Proportional-Integral (PI) and a Proportional-Derivative (PD) Controller. In addition to the implementation of control algorithms, the importance of various design criteria necessary to achieve satisfactory control performance is explored including parameters such as pressure transducer spacing, shock localization speed, flap-motor actuation speed and actuator resolution. Experimental results are presented for various test scenarios such as regulation of the shock location in the presence of stagnation pressure disturbances as well as tracking of time-varying step inputs. Performance and robustness properties of the tested control implementations are discussed. Further areas of improvement for the closed-loop control system in both hardware and software are discussed, and the need for reduced-order dynamics-based controllers is presented. / text

Analytical solutions to complex trajectory design problems are scarce, since only a few specific cases allow for closed-form solutions. The main purpose of this dissertation is to design simple algorithms for trajectory design using continuous thrust, with a focus on low-thrust applications. By “simple” here we seek to achieve algorithms that either admit an analytical solution, or require minimal input by the user and minimal computation time. The three main contributions of this dissertation are: designing Lyapunov-based closed-loop guidance laws for orbit transfers, finding semi-analytical solutions using a constant magnitude thrust, and perturbation theory for approximate solutions to low-thrust problems. The technical aspect that these problems share in common is that they all use, fully or partially, a thrusting model in which the energy of the system is kept constant. Many orbit transfer problems are shown to be solved with this thrusting protocol. / text

本論文分為兩部分，第一部份為以台灣之封閉型基金探討訊息事件下之投資者敏感性與市場效率性。第二部份為以東南亞六家國家基金探討投資者過渡反應之現象同時研究訊息分類後之訊息效果。 / This dissertation studies investors’ sentiment to dramatic public information events and the news effect on the valuation of closed-end funds. There are two main issues included in this dissertation. For the issue of investors’ sentiment, we employ domestic closed-end funds from Taiwan to test how political information events affect fund share price and net asset value. The political information events employed are the 1996 and 2000 presidential elections in Taiwan, including prominent political events ahead of the elections. For the other issue of news effect on the valuation of closed-end country funds, the six Asian country funds listed on the New York Stock Exchange are employed and the country-specific news are culled from the headlines shown on the front page of The New York Times. For investors’ sentiment, we examine how dramatic political news and events affect closed-end fund data, fund price, and net asset value, using a sample of Taiwan data. We use data from Taiwan, because its stock market has been repeatedly affected by political events. We develop a theoretical model to show how information shocks would affect the discounts on closed-end funds. In designing the model, which is tested below, we start by assuming that the information shock is consistent with market efficiency. Our empirical results show that, even though this assumption is corroborated by three out of four events, the remaining one event in four induces changes which are inconsistent with market efficiency. This provides support for the theory of the preponderance of investors’ sentiment. The results also show that the return on fund share prices and the return of net asset value (NAV) move in the same direction and the impact of information shocks to the return of fund share price and return of NAV have mostly the same sign. Although the results from domestic funds, with fund share prices and NAV that are valued in the identical market, tell us that there exists investors’ sentiment, we intend to resolve what the information effects are on the valuation of closed-end country funds that have fund share prices and NAV valued in two different entities/markets. We use a sample of six Asian country funds, listed on the New York Stock Exchange, to test whether salient country-specific news affects investors’ reaction around the Asian financial crisis period. Our results show that in regular weeks, fund share prices react less to changes in fundamentals. In weeks with salient news appearing on the front page of The New York Times, fund share prices react much more than those in regular weeks. We also find that economic news affects the adjustment process of fund share prices more significantly before and during the Asian financial crisis periods. These results are consistent with the hypothesis that news events play a role in the magnitude of investors’ reaction to changes in the fundamental values of closed-end country funds. As to the reaction of volume to news, the results show that news effect is significant in full sample period. For the reaction of volume to categorized news, economic news is significant in full sample period. In sum, the results from either domestic funds or country funds all show that news events/information do play a role in individual investors’ sentiment. The phenomenon is more conspicuous during a financial crisis period.

Section 26 of the Labour Relations Act 95 of 1996 makes provision for the introduction of closed shop agreements at the workplace between majority unions and employers. All employees covered by such agreements are required to be members of such unions or otherwise face the possibility of dismissal. "Conscientious objector" employees are an exception to this rule. The purpose of this submission is to investigate the constitutional validity of s26 in the light of the fundamental right to freedom of association in the Constitution of the Republic of South Africa, 1 996 whilst investigating the position of "conscientious objectors" in certain foreign jurisdictions. / Thesis (LL.M. (Labour Law))--North-West University, Potchefstroom Campus, 2006.

This thesis contributes to the general body of knowledge of research into engineering education. The main scope of the thesis is on enhancing laboratory education. There are three main types of laboratory: virtual, hands-on and remote. The hands-on lab is the oldest and most commonly used medium for experiential education in undergraduate degrees of science and engineering. The literature review of laboratory education has shown that hands-on labs suffer from many disadvantages, which can be overcome by utilizing hybrid laboratory structures that incorporate virtual and/or remote modes. The investigation into enhanced laboratory education is achieved via implementing new technical and pedagogical models of conducting laboratories. The technical model incorporates three access modes (virtual, hands-on and remote) to the laboratory experience in one software package called the TriLab. The TriLab concept has been applied to the Process Control Lab at the Chemical Engineering Department of Loughborough University and has been implemented using LabVIEW. The Joomla web content management system was used to develop an online portal for disseminating the remote component of the TriLab resulting in the first remote lab portal of Loughborough University and one of the few available in the UK. A pedagogical model of laboratory education based on Kolb's experiential learning theory and by the utilization of the TriLab concept is proposed. The model is built on a hypothesis, which states that the poor learning outcomes of hands-on laboratory sessions can be associated with poor activation of the stages of Kolb's experiential learning cycle. It has been proposed that access to a virtual lab in a preparatory session will play a role in activating the stages of Kolb's cycle. To verify this, educational experimentation procedures were designed and applied to two groups, control and experimental. Measurements via pre- and post-lab tests, marks for the laboratory report and the final exam of the module have been performed. The statistical analysis of the measurements has supported the stated hypothesis and solution proposal. The proposed pedagogical model is one of the few that provide a way of conducting laboratory education based on constructivist educational theories. (Continues...).

The world-wide development of new high-speed rail lines has led to more stringent design requirements for railway bridges, mainly because high-speed trains can cause resonance in the bridge superstructure. Dynamic simulations, often utilising time-consuming finite element analysis (FEA), have become essential for avoiding such problems. Therefore, guidelines and tools to assist structural engineers in the design process are needed. Considerable effort was spent at the beginning of the project, to develop simplified models based on two-dimensional (2D) Bernoulli-Euler beam theory. First, a closed-form solution for proportionally damped multi-span beam, subjected to moving loads was derived (Paper I). The model was later used to develop design charts (Paper II) and study bridges on existing railway lines (Paper III). The model was then extended to non-proportionally damped beams (Paper IV) in order to include the effects of soil-structure interactions. Finally, the importance of the interaction between the surrounding soil and the bridge was verified by calibrating a finite element (FE) model by means of forced vibration tests of an end-frame bridge (Paper V). Recommendations on how to use the models in practical applications are discussed throughout the work. These recommendations include the effects of shear deformation, shear lag, train-bridge and soil-structure interactions, for which illustrative examples are provided. The recommendations are based on the assumption that the modes are well separated, so that the response at resonance is governed by a single mode. The results of the work show that short span bridges, often referred to as `simple´ bridges, are the most problematic with respect to dynamic effects. These systems are typically, non-proportionally damped systems that require detailed analyses to capture the `true´ behaviour. Studying this class of dynamic system showed that they tend to contain non-classical modes that are important for the structure response. For example, the bending mode is found to attain maximum damping when its undamped natural frequency is similar to that of a non-classical mode. / <p>QC 20170213</p>

L’apparition de robots de service de plus en plus complexes ouvre de nouvelles perspectives quant aux tâches de manipulation d’objets. Malgré les progrès récents des techniques de planification de mouvement, peu d'entre elles s'intéressent directement à des systèmes multi-bras comme les torses humanoïdes. Notre contribution à travers cette thèse porte sur trois aspects. Nous proposons une technique de planification de mouvement performante basée sur la coordination des mouvements du système multi-bras. Elle exploite au mieux la structure du système en la divisant en parties élémentaires dont les mouvements sont planifiés indépendamment du reste du système. La fusion des différents réseaux élémentaires générés est ensuite réalisée dans le but d’obtenir un graphe prenant en compte le robot tout entier. Une seconde contribution porte sur l'extension des méthodes de planification pour des robots présentant des chaînes cinématiques fermées. Ces boucles cinématiques apparaissent dans le système lorsque, par exemple, le torse humanoïde saisit un objet avec plusieurs bras. Cette méthode traite explicitement les configurations singulières des manipulateurs, offrant ainsi une meilleure maniabilité de l’objet. Finalement, nous proposons deux approches pour la planification de tâches de manipulation d'objets par un torse humanoïde. La première concerne la résolution d’une tâche de prise et pose d'objets par un torse humanoïde à deux bras dans le cas où les contraintes imposées par la tâche nécessitent le passage par une double prise afin de transférer l'objet d'une main à l'autre. La seconde porte sur la résolution du même type de tâche par un manipulateur mobile. La thèse, effectuée dans le cadre du projet européen Phriends, présente les résultats d'expérimentations réalisées sur le robot Justin, démonstrateur du projet. / The emergence of new more and more complex service robots opens new research fields on objet manipulation. Despite the recent progresses in motion planning techniques, few of them deal directly with multi-arm systems like humanoid torsos. Our contribution through this thesis focuses on three aspects. We present an efficient motion planning technique based on the multi-arm system motion coordination. It takes advantage of the system's structure by dividing it into elementary parts of which movements are planned independently of the rest of the system. Generated elementary networks are then fused to obtain a roadmap that takes into account the whole robot. The second contribution consists of the extension of motion planning methods for a robot under loop closure constraints. These kinematic loops appear in the system when, for example, the humanoid torso grasps an objet with two arms. This method treats explicitly the singular configurations of the manipulators, providing better handling of the object. Finally, we present two approaches for planning object manipulation tasks by humanoid torsos. The first concerns solving pick and place task by humanoid torso where the imposed task constraints require a passage through a double grasp to transfer the object from one hand to the other. The second approach concerns the resolution of the same type of task by a mobile manipulator. The presented methods have been integrated on a real platform, Justin, and validated with experiments in the frame of E.U. FP-6 PHRIENDS project.

FPGA stands for Field Programmable Gate Array and it is a technology that has been on the rise the last decades. With a decrease in size of the logic elements commercially available products have started to have more built-in functionality in one package and by being reprogrammable makes the system a powerful competitor among its neighbors. FPGA technology in comparison with Digital Signal Processing technology is generally interesting because of the parallelism of the programming that can be made. This allows for more operations in less time. In this thesis a system is developed to control power converters with control signals in high frequency. A previous project is used as a base and a toolchain of new components are implemented to create a new, more generic system. The previous system is evaluated and a new protocol for communication is developed. The toolchain with the necessary control blocks is implemented in Quartus II that includes a timer block, a pulse width modulation block, a PID controller block and a FIR-filter block. The system is used to control a power converter and the result is evaluated.