Reproduction de : Thèse de doctorat : Sciences et Techniques industrielles : Toulon : 2006. / Titre provenant du cadre-titre. Références bibliographiques p.129-132.

ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / The U.S. Army Research Laboratory (ARL) is developing an onboard instrument and telemetry system to obtain measurements of the 30mm MK310 projectile's in-flight dynamics. The small size, high launch acceleration, and extremely high rates of this projectile create many design challenges. Particularly challenging is the high spin rate which can reach 1400 Hz at launch. The bandwidth required to continuously transmit solar data using the current method for such a rate would leave no room for data from other sensors. To solve this problem, a data compression scheme is implemented that retains the resolution of the solar sensor data while providing room in the telemetry frame for other measurements.

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Software maintenance is a significant phase of a software life-cycle. Once a system is developed the main focus shifts to maintenance to keep the system up to date. A system may be changed for various reasons such as fulfilling customer requirements, fixing bugs or optimizing existing code. Code needs to be studied and understood before any modification is done to it. Understanding code is a time intensive and often complicated part of software maintenance that is supported by documentation and various tools such as profilers, debuggers and source code analysis techniques. However, most of the tools fail to assist in locating the portions of the code that implement the functionality the software developer is focusing. Mining execution traces can help developers identify parts of the source code specific to the functionality of interest and at the same time help them understand the behaviour of the code. We propose a use-driven hybrid framework of static and dynamic analyses to mine and manage execution traces to support software developers in understanding how the system's functionality is implemented through feature analysis. We express a system's use as a set of tests. In our approach, we develop a set of uses that represents how a system is used or how a user uses some specific functionality. Each use set describes a user's interaction with the system. To manage large and complex traces we organize them by system use and segment them by user interface events. The segmented traces are also clustered based on internal and external method types. The clusters are further categorized into groups based on application programming interfaces and active clones. To further support comprehension we propose a taxonomy of metrics which are used to quantify the trace. To validate the framework we built a tool called TrAM that implements trace mining and provides visualization features. It can quantify the trace method information, mine similar code fragments called active clones, cluster methods based on types, categorise them based on groups and quantify their behavioural aspects using a set of metrics. The tool also lets the users visualize the design and implementation of a system using images, filtering, grouping, event and system use, and present them with values calculated using trace, group, clone and method metrics. We also conducted a case study on five different subject systems using the tool to determine the dynamic properties of the source code clones at runtime and answer three research questions using our findings. We compared our tool with trace mining tools and profilers in terms of features, and scenarios. Finally, we evaluated TrAM by conducting a user study on its effectiveness, usability and information management.

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The design of bicycle frames has remained fairly static for the majority of the past century, but recent increases in demand for high performance bicycles has created an accelerated design cycle that requires innovation. In order to design new frames with confidence in their capacity to withstand the rigors of use, reliable data about the nature of that use is needed, but this data is not currently available. The purpose of this research was to develop and implement a system that is capable of interpolating loads applied to a bicycle frame during vigorous riding for the purpose of improving the quality of information available to bicycle designers. The system that was developed employed finite element modeling to locate strain gauges on a frame and a least-squares approximate solution of strain readings to interpolate the applied loads. At its best, the system is capable of resolving loads with better than a 2% error. This system is limited, though, as it can only be applied in cases where the frame has a significant strain reaction to a load case but does not have a significant change in geometry during loading. This system was implemented on a cross-country mountain bicycle frame for the purposes of determining a rider weight to load relationship and to compare the standardized test procedures for bicycles to the loads experienced in the field. It was confirmed that there is a linear relationship between rider weight and load on the frame for all component forces except that applied to the bottom bracket, out of plane with the bicycle frame. It was also found that the British Standards fatigue testing practices, which are used internationally to assess bicycle safety, are inconsistent in their representation of realistic riding conditions when compared with the results from the field tests. Some loads appear conservative, some offer a very large factor of safety, and two are not represented at all. In particular, the moment about the bottom bracket due to pedaling and the load on the seat from the rider appear to consistently exceed the standardized test requirements while the moment caused by fork splay seems much smaller than the tests demand.

This thesis focuses on controller design and analysis for induction motor (IM) drives, flux control for electrically excited synchronous motors with damper windings (EESMs), and to enhance voltage sag ride-through ability and analysis for a wind turbine application with a full-power grid-connected active rectifier. The goal is to be able to use the existing equipment, without altering the hardware. Further, design and analysis of the stabilization of DC-link voltage oscillations for DC systems and inverter drives is studied, for example traction drives with voltage sags in focus. The proposed IM controller is based on the field-weakening controller of Kim and Sul [31], which is further developed. Applying the proposed controller to voltage sag ride-through gives a cheap and simple ride-through system. The EESM controller is based on setpoint adjustment for the field current controller. The analysis also concerns stability for the proposed flux controller. The DC-link stabilization algorithm is designed following Mosskull [38], where a component is added to the current controller. The algorithm is further developed. Analysis is the main focus, and concerns the impact of the different parameters involved. Proper parameter selection for the controller, switching frequency, and DC-link capacitor is given. The impact of voltage sags is investigated for a power-grid-connected rectifier. Here, we analyze the impact of different types of voltage sags and phase-angle jumps. The analysis gives design rules for the DC-link capacitor and the switching frequency. Experimental results and simulations verify the theoretical results. / QC 20101012

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