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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

STUDY ON HARDWARE REALIZATION OF GPS SIGNAL FAST ACQUISITION

Lei, Huang, Yanhong, Kou, Qishan, Zhang 10 1900 (has links)
ITC/USA 2005 Conference Proceedings / The Forty-First Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2005 / Riviera Hotel & Convention Center, Las Vegas, Nevada / In GPS receiver the acquisition process generates two important parameters: the initial carrier frequency and the initial phase of the C/A code. In this paper two different methods for acquisition are mainly discussed: serial search in the time domain and FFT search in the frequency domain. Frequency domain acquisition involves using the Fast Fourier Transform (FFT) to convert the GPS signals into the frequency domain. One fast and easy-to-implement algorithm for averaging correlation is implemented and explained in detail. The FFT search method is both simulated in Matlab and evaluated in Altera Stratix DSP development board.
72

An Aspect Pointcut for Parallelizable Loops

Dean, John Scott 01 January 2013 (has links)
This study investigated the need for a pointcut for parallelizable loops in an aspect-oriented programming environment. Several prototype solutions exist for loop pointcuts, but the solutions are not very granular. In particular, they are not able to differentiate between loops that are parallelizable and those that are not. Being able to identify parallelizable loops automatically, as part of an aspect-oriented compiler's weaving process, is particularly important because (1) manually identifying parallelizable loops is known to be a difficult problem and (2) aspectizing parallelized loops can lead to a reduction in code tangling and an increase in separation of concerns. This paper describes the concepts behind the loop-pointcut problem. It then describes the approach used in this study for implementing a solution in the form of an aspect-oriented Java compiler with a parallelizable loop pointcut. Identifying parallelizable loops is known to be a difficult problem, and as such, this study's parallelizable loop pointcut implements a heuristic solution. The pointcut identifies many parallelizable loops as being parallelizable, but in erring on the side of conservatism, there are some parallelizable loops that the pointcut is unable to identify as parallelizable. To test the parallelizable-loop pointcut, the pointcut was applied to a benchmark set of parallelizable programs. There were two versions of each benchmark program - (1) an aspect-oriented version, where the aspect-oriented compiler's weaver added the multi-threading functionality, and (2) a non-aspect-oriented version, where the benchmark program's source code directly implemented the multi-threading functionality. For each benchmark program, the output from the aspect-oriented version was compared to the output from the non-aspect-oriented version. The study found that each loop that was deemed parallelizable by the aspect-oriented benchmark program was executed in parallel (with multiple threads) by both versions of the program - the aspect-oriented version and the non-aspect-oriented version. There were some loops in the non-aspect-oriented benchmark programs that were deemed parallelizable and executed in parallel, but those same loops were deemed non-parallelizable by their associated aspect-oriented benchmark program. This discrepancy is explained by the study's conservative approach to identifying loops as parallelizable.
73

Aspects of advanced controller design and implementation

Arelhi, Roselina January 1999 (has links)
No description available.
74

An investigation of the working memory capacity of individuals with Down syndrome, with and without dementia of the Alzheimer's type

Doswell, Sophie January 2001 (has links)
No description available.
75

Development of A Kinetic Model For Loop-Free Colonoscopy Technology

2013 September 1900 (has links)
The colonoscope is an important tool in diagnosis and management of diseases of the colon. One of the ongoing challenges with this device is that the colonoscope may form a loop together with the colon during the procedure. The result of the loop is that further insertion of the scope in the colon may not be possible. The loop may also cause risks of perforation of the colon and pain in the patient. There are currently several existing devices to overcome loop formation in colonoscopy, some of which have been introduced in clinical work. However, empirical assessment shows that these devices do not work very well. This is the motivation for the research presented in this thesis. In this thesis, a new paradigm of thinking, “doctor-assisted colonoscopy,” is proposed to overcome loop formation. In this new approach, the physician’s role is enhanced with new information that is acquired by sensors outside the human body and inferred from the mathematical model. It is referred to as a kinetic model due to the fact that this model describes the kinetic behaviour of the scope. This thesis is devoted to development of this kinetic model. In this study, the model of the colonoscope and the model of the colon are developed based on the Timoshenko beam theory, and parameters in both models are determined by the experiments. The following conclusions then are made: (1) self-locking of the colonoscope is the most basic cause for a loop to occur, while structural instability of the colonsocope is dependent on the self-locking; (2) both the scope and the colon can be well represented with the Timoshenko beam elements and the Linear Complementary Problem (LCP) formulation derived from Signorini’s law, and Coulom’s law for representation of interactions between the colon and scope is adequate; (3) there are effects from the location, looping, and tip deflection of the scope on flexural rigidity of the scope. Approximately, the flexural rigidity of the CF-Q160L colonoscope ranges from 300 to 650 N•cm2, and its accuracy is proven by a good agreement between the model predicted result and experimental result; (4) Rayleigh damping for the CF-Q160L colonoscope depends more on the mass matrix [M] of the colonoscope than the stiffness matrix [K], which is evident by the large coefficient value of “alpha” (0.3864) and the small coefficient value of “beta” (0.0164). The contributions of this thesis are: (1) the finding that the main cause of the loop is not structural instability of the colonoscope but rather self-locking of the colonoscope, which could lead to design of a “new-generation” colonoscope to avoid the loop; (2) a systematic evaluation of the existing colonoscopy technologies based on the well-proven Axiomatic Design Theory (ADT), which will serve as a guideline for the development of future new colonoscopes in future; (3) an approach to developing a kinetic model of the colonoscope useful to modeling similar objects such as a catheter guide-wire; (4) a novel ex-vivo colonoscopy test-bed with the kinetic and kinematic measurements useful for validation of new designs in colonoscopy technology and also useful for training physicians who perform the colonoscopy procedure; and (5) a new paradigm of thinking for colonoscopy called “doctor-assisted colonoscopy,” which has potential applications to other medical procedures such as catheter-based procedures.
76

Closed-Loop Tracking System Provides Reference for Data Collection Exercises

Wallace, Keith, Weinberg, Patrick 10 1900 (has links)
International Telemetering Conference Proceedings / October 26-29, 1992 / Town and Country Hotel and Convention Center, San Diego, California / A computational system was developed to support data collection for advanced airborne technology research. Basic research is conducted using a variety of sensing devices for collection of flight characteristics data from aircraft. To maximize control over as many variables as possible during research activities, a controlled aircraft tracking environment is needed to provide reference data for real-time operation and post-mission analysis. The solution to this requirement is realized with the ACMI Interface System (ACINTS). The ACINTS extracts real-time tracking data from a closed-loop telemetered tracking array, reprocesses needed parameters, provides reference data (positioning and control commands) to the sensor device, and records aircraft kinematics for later correlation with other collected data.
77

Testbänk för turbinregulator

Vårdenius Lindqvist, Anders January 2016 (has links)
The function of a turbine governor is to maintain the grid frequency close to the nominal value, which in the Nordic grid is 50 Hz. This thesis uses a standard turbine governor from Vattenfall AB, which is implemented with a PLC. The turbine governor gives a control signal which controls the guide vane opening and thus the water flow through the turbine. A test bench for the turbine governor was created where the software LabView was used together with special hardware. The software simulates a Francis hydro power turbine, which gives a feedback signal to the turbine governor. Data for the hydro power turbine, used in the simulation, has been taken from an actual power plant. The user of the test bench has the possibility to choose between actions and to change parameters. For example to give start or stop order, or change setpoint. In this thesis has, for example, a change of guide vane opening setpoint, a grid disturbance, and stops of the turbine, been tested. Validation shows that the result agrees reasonably well with the reality. The result leads to the conclusion that it is possible to create a test bench for the turbine governor with the aid of LabView.
78

Development of a Low Cost Autopilot System for Unmanned Aerial Vehicles

Ortiz, Jose 10 August 2010 (has links)
The purpose of this thesis was to develop a low cost autonomous flight control system for small unmanned aerial vehicles with the aim to support collaborative systems. A low cost hardware solution was achieved by careful selection of sensors, integration of hardware subsystems, and the use of new microcontroller technologies. Flight control algorithms to guide a vehicle though waypoint based flight paths and loiter about a point were implemented using direction fields. A hardware in the loop simulator was developed to ensure proper operation of all hardware and software components prior to flight testing. The resulting flight control system achieved stable and accurate flight while reducing the total system cost to less than $250.
79

The use of computational fluid dynamics to simulate the flow in a high recirculation airlift reactor

de Souza, Althea Caroline January 2000 (has links)
No description available.
80

Estruturação genética de Stenella coeruleoalba Meyen, 1833 no Oceano Atlântico

FREIRE, M. C. C. 07 April 2017 (has links)
Made available in DSpace on 2018-08-01T23:27:10Z (GMT). No. of bitstreams: 1 tese_10881_81 - Mylla Carla Cescon Freire.pdf: 1313608 bytes, checksum: 57fa1668897624f985a8b3440fe12072 (MD5) Previous issue date: 2017-04-07 / O Stenella coeruleoalba é um pequeno cetáceo pelágico da família Delphininae que apresenta uma ampla distribuição e pode ser encontrado em águas tropicais e temperadas dos oceanos Atlântico, Pacífico e Índico, bem como em mares adjacentes, como o Mar Mediterrâneo. O presente estudo teve por objetivo analisar a região do citocromo b (Cit-b) e a região controle (D-loop) do DNA mitocondrial de indivíduos do Nordeste e do Sul do Brasil (Oceano Atlântico Sul), além de compará-las com sequências de golfinhos-listrados provenientes do Oceano Atlântico Norte, e com isso avaliar os índices de diversidade e a presença ou a ausência de estruturação genética entre as diferentes localidades. Os S. coeruleoalba do Brasil apresentaram uma alta diversidade genética para ambos os marcadores mitocondriais analisados (D-loop: h= 0,984; π= 0,294; Cit-b: h= 0,848; π= 0,249) e considerando o marcador Cit-b constituem duas populações (FST= 0,180; P= 0,045). Uma diferenciação significativa entre as unidades amostrais de S. coeruleoalba do Atlântico Norte e do Atlântico Sul foi verificada a partir dos dois marcadores mitocondriais avaliados (D-loop: FST= 0,034/ P= 0,009; Cit-b: FST= 0,130/ P= 0,026). Ademais, com a região D-loop, foi possível evidenciar estruturação genética entre dois grupos de golfinhos-listrados do Mar Mediterrâneo (FST= 0,0913/ P= 0,000). Não foi possível identificar estruturação entre os indivíduos do oeste do Oceano Atlântico Norte com as unidades amostrais do Brasil, mesmo estes não apresentando compartilhamento de haplótipos. Tal fato sugere que estas unidades possam ter surgido de linhagens próximas geneticamente e ainda fazem parte de uma mesma população. Até então, nenhum estudo genético populacional com a espécie S. coeruleoalba havia sido realizado no Oceano Atlântico Sul. Entender como os golfinhos-listrados encontram-se estruturados é de suma importância para compreender a genética destes indivíduos e assim definir estratégias de conservação adequadas para cada população identificada.

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