An N-bit digitally variable ultra wideband pulse generator for GPR and UWB applications

This paper presents a low-cost Ultra Wideband (UWB) pulse generator that can vary the pulse duration digitally by using a Step Recovery Diode (SRD), microstrip transmission lines and PIN diodes. First, a sharp edge is generated by using a SRD circuitry. Then a pulse is formed from the sharp edge through the use of transmission lines and the PIN diodes. Based on the number of transmission lines (N), the duration of the pulse can be varied in steps. The UWB pulse generator circuits are implemented on an FR-4 substrate using microstrip line technology and UWB pulses with durations of 550 to 2400 psec are measured. N2 Ke

New VLSI design of a MAP/BCJR decoder.

Any communication channel suffers from different kinds of noises. By employing forward error correction (FEC) techniques, the reliability of the communication channel can be increased. One of the emerging FEC methods is turbo coding (iterative coding), which employs soft input soft output (SISO) decoding algorithms like maximum a posteriori (MAP) algorithm in its constituent decoders. In this thesis we introduce a design with lower complexity and less than 0.1dB performance loss compare to the best performance observed in Max-Log-MAP algorithm. A parallel and pipeline design of a MAP decoder suitable for ASIC (Application Specific Integrated Circuits) is used to increase the throughput of the chip. The branch metric calculation unit is studied in detail and a new design with lower complexity is proposed. The design is also flexible to communication block sizes, which makes it ideal for variable frame length communication systems. A new even-spaced quantization technique for the proposed MAP decoder is utilized. Normalization techniques are studied and a suitable technique for the Max-Log-MAP decoder is explained. The decoder chip is synthesized and implemented in a 0.18 mum six-layer metal CMOS technology. (Abstract shortened by UMI.)Dept. of Electrical and Computer Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .S23. Source: Masters Abstracts International, Volume: 43-05, page: 1783. Adviser: Majid Ahmadi. Thesis (M.A.Sc.)--University of Windsor (Canada), 2004

Integrated sensors for process monitoring and health monitoring in microsystems

This thesis presents the development of integrated sensors for health monitoring in Microsystems, which is an emerging method for early diagnostics of status or “health” of electronic systems and devices under operation based on embedded tests. Thin film meander temperature sensors have been designed with a minimum footprint of 240 m × 250 m. A microsensor array has been used successfully for accurate temperature monitoring of laser assisted polymer bonding for MEMS packaging. Using a frame-shaped beam, the temperature at centre of bottom substrate was obtained to be ~50 ºC lower than that obtained using a top-hat beam. This is highly beneficial for packaging of temperature sensitive MEMS devices. Polymer based surface acoustic wave humidity sensors were designed and successfully fabricated on 128° cut lithium niobate substrates. Based on reflection signals, a sensitivity of 0.26 dB/RH% was achieved between 8.6 %RH and 90.6 %RH. Fabricated piezoresistive pressure sensors have also been hybrid integrated and electrically contacted using a wire bonding method. Integrated sensors based on both LiNbO3 and ZnO/Si substrates are proposed. Integrated sensors were successfully fabricated on a LiNbO3 substrate with a footprint of 13 mm × 12 mm, having multi monitoring functions for simultaneous temperature, measurement of humidity and pressure in the health monitoring applications

Employment of dual frequency excitation method to improve the accuracy of an optical current sensor, by measuring both current and temperature.

Optical current sensors (OCSs) are initially developed to measure relatively large current over a wide range of frequency band. They are also used as protective devices in the event a fault occurs due to a short circuit, in the power generation and distribution industries. The basic principal used in OCS is the Faraday effect. When a light guiding faraday medium is placed in a magnetic field which is produced by the current flowing in the conductor around the magnetic core, the plane of polarization of the linearly polarized light is rotated. The angle of rotation is proportional to the magnetic field strength, proportionality constant and the interaction length. The proportionality constant is the Verdet constant V (λ, T), which is dependent on both temperature and wavelength of the light. Opto electrical methods are used to measure the angle of rotation of the polarization plane. By measuring the angle the current flowing in the current carrying conductor can be calculated. But the accuracy of the OCS is lost of the angle of rotation of the polarization plane is dependent on the Verdet constant, apart from the magnetic field strength. As temperature increases the Verdet constant decreases, so the angle of rotation decreases. To compensate the effect of temperature on the OCS, a new method has been proposed. The current and temperature are measured with the help of a duel frequency method. To detect the line current in the conductor or coil, a small signal from the line current is fed to the reference of the lock in. To detect the temperature, the coil is excited with an electrical signal of a frequency different from the line frequency, and a small sample of this frequency signal is applied to the reference of the lock in. The temperature and current readings obtained are look up at the database value to give the actual output. Controlled environment is maintained to record the values in the database that maps the current and temperature magnitude values at the DSP lock in amplifier, to the actual temperature and current. By this method we can achieve better compensation to the temperature changes, with a large dynamic range and better sensitivity and accuracy

Contribuição para o mapeamento tridimensional usando imagem

Dissertação de mestrado em Engenharia MecatrónicaA elaboração desta Tese pretende juntar num só documento conhecimento existente sobre a temática do mapeamento tridimensional de objectos, em particular os métodos ópticos. Posteriormente poderá ser utilizado como ferramenta de trabalho, sendo um ponto de partida para novos trabalhos sobre o tema. Com este objectivo foi feita uma pesquisa sobre o estado da arte. Foram comparados os métodos de mapeamento com contacto e sem contacto, foram apresentadas as desvantagens e vantagens de cada um deles. No que toca aos métodos ópticos sem contacto eles dividem-se em métodos passivos e métodos activos. Os métodos passivos descritos são a visão estéreo passiva e a fotogrametria. O principal problema da visão estéreo passiva é a correspondência entre imagens. A fotogrametria é muito utilizada na reconstrução tridimensional a partir de imagens bidimensionais. Os métodos activos descritos são a triangulação laser, estruturada simples e codificada, tempo de propagação e franjas de Moiré. A triangulação laser, baseia-se na projecção de uma linha ou ponto laser, a luz é reflectida e captada por uma câmara ou detector óptico, segundo uma determinada direcção. A luz estruturada é dos métodos activos mais utilizado e baseia-se na projecção de luz estruturada que pode ser simples ou codificada. O tempo de propagação consiste em enviar um sinal e medir as propriedades do sinal que é devolvido. Finalmente, as franjas de Moiré que é um padrão de interferência gerado pela sobreposição de duas grelhas. É conhecida as imperfeições que são introduzidas nas imagens, muito particularmente, nos equipamentos de captação de imagem de baixo custo. Quando se realizam medições a partir de imagens é necessário corrigir essas imperfeições. Neste trabalho, foi introduzido um capítulo onde a distorção das lentes e a calibração das câmaras são abordados. Foi também introduzido nesta tese um capítulo sobre modelação de sólidos, com a intenção de mostrar formas de representação de sólidos, que terá significado aquando do reconhecimento de formas, a partir da nuvem de pontos obtida através do mapeamento tridimensional. Na implementação prática procurou-se sobretudo apresentar um processo de correcção da distorção da imagem. Foi desenvolvida uma aplicação de detecção de pontos numa imagem e foi aplicado a esses pontos um método de correcção da distorção baseado nas invariantes geométricas. Foi ainda descrito um sistema de mapeamento tridimensional baseado em luz estruturada, composto por um projector de padrões e uma câmara de captação de imagem. No final são apresentadas as conclusões e trabalhos futuros

Quality prediction in manufacturing system design.

Manufacturing system design can significantly affect the resulting product quality level. Therefore, the early prediction of product quality, as affected by manufacturing system configuration decisions, can enhance the manufacturer\u27s competitiveness through achieving higher quality levels at lower costs in a responsive manner. In this research, a conceptual framework is proposed for the proactive assessment of product quality in terms of the manufacturing system configuration parameters. A new comprehensive model that can be used in comparing different system configurations based on quality is developed using Analytic Hierarchy Process. In addition, a hierarchical fuzzy inference system is developed to model the ill-defined relation between manufacturing system design parameters and the resulting product quality. This model is capable of mapping the considered manufacturing system configuration parameters into a Configuration Capability Indicator (CCI), expressed in terms of sigma capability level, which can be compared to the benchmark Six Sigma capability. The developed models have been applied to several case studies (Test Parts ANC-90 and ANC-101, Cylinder Head Part Family, Gearbox Housing, Rack Bar Machining, and Siemens Jeep Intake Manifold) with different configuration scenarios for illustration and verification. The results demonstrate the capabilities of the CCI in comparing different system configurations from quality point of view and in supporting the decision-making during the early stages of manufacturing system development. The included application of the developed models emphasized that high quality levels can be achieved by investigating all the improvement opportunities and it is recommended that efforts should be directed in the first place to design the system with high defect prevention capability. This can be achieved by using highly capable processes, implementation of mistake proofing techniques, as well as minimizing variability due to parallel processing and variation stack up. Considering the relationship between quality and complexity, it has been concluded that the CCI represents the time-independent real complexity of a system configuration. Furthermore, it has been demonstrated that the product complexity adversely affects the resulting product quality. Therefore, it is recommended that high product quality levels can be achieved not only by using highly capable system configurations, but also by minimizing the product complexity during the design stage.Dept. of Industrial and Manufacturing Systems Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2006 .N33. Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 4035. Thesis (Ph.D.)--University of Windsor (Canada), 2006

Studio e sviluppo di un sistema di interrogazione di Fiber Bragg Grating Sensors implementato tramite Array Waveguide Gratings

In questa tesi si affronta lo studio dettagliato di un interrogatore di Fiber Bragg Grating Sensors tramite Array Waveguide Gratings controllabili in temperatura. Dopo aver risolto le problematiche ottiche e creato un set-up funzionante, viene progettata, realizzata e collaudata un'apposita scheda elettronica atta a condizionare, amplificare e campionare i segnali ottici oggetti di studio

Evaluation of non-intrusive monitoring for condition based maintenance applications on US Navy propulsion plants

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering; and, (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (p. 107-108).The thesis explores the use of the Non-intrusive Load Monitor (NILM) in Condition Based Maintenance (CBM) applications on US Navy ships as part of the Office of Naval Research Electric Ship Integration (ESI) Initiative. The NILM is a device that measures an electrical component's performance by applying a single voltage and current transducer to a ship's existing power distribution system. The NILM was originally developed to monitor electrical power usage in buildings where it was noticed that it could disaggregate and report the operation of individual loads when many loads were present. The limits of this capability are explored by employing a signal processing script in MATLAB using component data gathered on the USCGC SENECA (WMEC-906). The plausibility of using a few NILMs to provide machinery monitoring information for an entire engineering space, and the resulting opportunity to reduce sensor growth on future Navy ships is explored. Then efforts to monitor naval propulsion plant machinery with the NILM are discussed. Two NILMs were constructed and installed on selected individual components at the Naval Surface Warfare Center Philadelphia DDG-51 Land Based Engineering Site (LBES).(cont.) Monitoring of the Fuel Oil and Low Pressure Air Service Systems was conducted during a week long certification of the pre-commissioning crew of the USS BAINBRIDGE (DDG-96). Data collected was then used to explore the use of the NILM as a diagnostic device for shipboard systems through the evaluation of mechanical transients in the Fuel Oil system and a test leak inserted into the Low Pressure Air System. Additionally, a brief overview of the Multi-function Monitor (MFM), a type of electrical protection equipment installed on many US Navy ships, is provided. The MFM could provide a natural installation point on the ship's power distribution system to monitor a multiple loads. Finally, an evaluation of the NILM as an enabling technology for Navy CBM was conducted. The Integrated Condition Assessment System (ICAS) is the U.S. Navy's "Program of Record" for CBM and is currently installed on over 97 ships fleet wide. NILM data from individual components at the LBES was monitored simultaneously with ICAS and the results are compared.by William C. Greene.S.M