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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.
1

Efter bonusfesten : En studie om användandet av de rörliga ersättningssystemen och deras legitimitet i efterdyningarna av finanskrisen. / After the bonus party : A study on the use of variable compensation systems and their legitimacy in the aftermath of the financial crisis.

Susanne, Danerlöv, Sabina, Olsson January 2013 (has links)
Med utgångspunkt i den livliga debatt som fördes kring bonusutbetalningar i samband med finanskrisen och det skadade förtroende för rörliga ersättningar den resulterade i syftar denna studie till att undersöka hur man idag återskapar legitima rörliga ersättningssystem. Studien ämnar även svara på frågan varför organisationer, trots stora kostnader, väljer att använda sig av rörliga ersättningssystem. Med agentteorin och nyinstitutionell teori som referensramar genomfördes en kvalitativ undersökning vilken bestod av sex semi-strukturerade expertintervjuer. Tre av dessa intervjuer genomfördes med representanter för tre olika organisationer, två av intervjuerna gjordes med oberoende konsulter som specialiserat sig på utformning av rörliga ersättningssystem och slutligen intervjuades en jurist som arbetar med föreskrifter gällande rörlig ersättning inom den finansiella sektorn. Analys av intervjuerna hanterades med etnografisk kvalitativ metodik som utgångspunkt för att skapa ett kodschema kopplat till vår teori. Två analysmodeller användes sedermera på de koder vi fick fram: Den komparativa analysen och den idealtypcentrerade analysen. I studien framkommer att organisationer alltmer använder sig av transparenta system för sina rörliga ersättningar i syfte att legitimera dessa. Alltfler anställda tenderar även att innefattas i det rörliga ersättningssystemet, oberoende av vilken befattning och funktion de har i organisationen, detta för att skapa en större acceptans för systemet. Resultatet visar att det dock fortfarande finns en klick anställda som i många fall står utanför de nyskapade rörliga ersättningssystemen: den högsta ledningen. Vidare finner vi i studien att organisationer använder rörliga ersättningssystem som en styrteknik; i och med att de kopplat ersättning till måluppfyllnad skapas en acceptans för systemet och ifrågasättande av de uppsatta målen minskar. / Based on the lively debate on bonus payments that took place due to the financial and damaged the trust for variable compensation systems, this study aims to answer the question of how to recover legitimate variable compensation for this present day. The study also intends to answer the question of why organizations, despite great expense, choose to use variable compensation systems. Using the New Institutional theory and the Agency theory as frameworks, a qualitative study is performed consisting of six semi-structured expert interviews. Three of these interviews were conducted with representatives of the three organizations, two of the interviews were conducted by independent consultants specializing in the design of variable compensation systems and the last interview was conducted with an expert on variable compensation in the financial sector. The analysis of the interviews was performed with an ethnographic quantitative methodology as a basis to create a coding scheme linked to the proposed theories. From this approach, the interviews were narrowed down to codes which were then analyzed with two different analytical models: the comparative analysis and the ideal type centered. The study shows that organizations tend to increasingly exceed the transparency in the compensation system in order to legitimize them. In addition, variable compensation systems tend to include a greater number of employees, at various levels and functions within the organization, with the purpose of creating a greater acceptance of the system. Despite this, there are still a group of employees which, to some extent, are outside the system: the top management and directors. Furthermore, this study finds that organizations tend use variable compensation as a control technique, due to the connection between compensation and performance that creates an acceptance of the system and decreases the questioning of goal-setting.
2

Projeto em FPGA de um controlador unificado para corre??o de fator de pot?ncia em retificadores boost bidirecionais monof?sicos

Soares, Antonio Wallace Antunes 18 December 2013 (has links)
Made available in DSpace on 2014-12-17T14:56:18Z (GMT). No. of bitstreams: 1 AntonioWAS_DISSERT.pdf: 2078440 bytes, checksum: 8f0b0683ae325a95be82dafa64af1734 (MD5) Previous issue date: 2013-12-18 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The use of Field Programmable Gate Array (FPGA) for development of digital control strategies for power electronics applications has aroused a growing interest of many researchers. This interest is due to the great advantages offered by FPGA, which include: lower design effort, high performance and highly flexible prototyping. This work proposes the development and implementation of an unified one-cycle controller for boost CFP rectifier based on FPGA. This controller can be applied to a total of twelve converters, six inverters and six rectifiers defined by four single phase VSI topologies and three voltage modulation types. The topologies considered in this work are: full-bridge, interleaved full-bridge, half-bridge and interleaved half-bridge. While modulations are classified in bipolar voltage modulation (BVM), unipolar voltage modulation (UVM) and clamped voltage modulation (CVM). The proposed project is developed and prototyped using tools Matlab/Simulink? together with the DSP Builder library provided by Altera?. The proposed controller was validated with simulation and experimental results / A utiliza??o de Field Programmable Gate Array (FPGA) para o desenvolvimento de estrat?gias de controle digital para aplica??es em eletr?nica de pot?ncia tem despertado um crescente interesse entre muitos pesquisadores. Tal interesse se deve as grandes vantagens apresentadas pelo FPGA, que incluem: menor esfor?o de projeto, alto desempenho e grande flexibilidade de prototipagem. Este trabalho prop?e o desenvolvimento e implementa??o de um controlador unificado, mediante o uso de FPGA, utilizando a t?cnica de controle de um ciclo (One-Cycle Control Technique) para corre??o de fator de pot?ncia com retificadores boost. Este controlador pode ser aplicado a um total de doze conversores, sendo seis inversores e seis retificadores, definidos pela topologia e pelo tipo de modula??o de tens?o. As topologias consideradas neste trabalho s?o: ponte completa, ponte completa intercalada, meia ponte e meia ponte intercalada. Enquanto que as modula??es s?o classificadas em modula??o bipolar de tens?o (MBT), modula??o unipolar de tens?o (MUT) e modula??o com grampeamento de tens?o (MGT). O projeto ? desenvolvido e prototipado utilizando as ferramentas Matlab?/Simulink em conjunto com a biblioteca DSP Builder, disponibilizada pela Altera?. O controlador proposto ? com resultados de simula??o e experimentais
3

A PFC Power Supply with Minimized Energy Storage Components and a New Control Ttechnique for Cascaded SMPS

Frost, Damien F. 04 December 2012 (has links)
This Master of Applied Science thesis proposes a new design of low power, power factor corrected (PFC), power supplies. By lifting the hold up time restriction for devices that have a battery built in, the energy storage elements of the converter can be reduced, permitting a small and inexpensive power converter to be built. In addition, a new control technique for controlling cascaded converters is presented, named duty mode control (DMC). Its advantages are shown through simulations. The system was proven using a prototype developed in the laboratory designed for a universal ac input voltage (85 - 265VRMS at 50 - 60Hz) and a 40W output at 12V. It consisted of two interleaved phases sensed and digitally controlled on the isolated side of the converter. The prototype was able to achieve a power factor of greater than 0.98 for all operating conditions, and input harmonic current distortion well below any set of standards.
4

A PFC Power Supply with Minimized Energy Storage Components and a New Control Ttechnique for Cascaded SMPS

Frost, Damien F. 04 December 2012 (has links)
This Master of Applied Science thesis proposes a new design of low power, power factor corrected (PFC), power supplies. By lifting the hold up time restriction for devices that have a battery built in, the energy storage elements of the converter can be reduced, permitting a small and inexpensive power converter to be built. In addition, a new control technique for controlling cascaded converters is presented, named duty mode control (DMC). Its advantages are shown through simulations. The system was proven using a prototype developed in the laboratory designed for a universal ac input voltage (85 - 265VRMS at 50 - 60Hz) and a 40W output at 12V. It consisted of two interleaved phases sensed and digitally controlled on the isolated side of the converter. The prototype was able to achieve a power factor of greater than 0.98 for all operating conditions, and input harmonic current distortion well below any set of standards.
5

Conversor estático de 9 chaves acionando máquina hexafásica. / Static converter of 9 switches driving hexaphase machine.

ROCHA, Adi Neves. 20 April 2018 (has links)
Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-20T22:15:13Z No. of bitstreams: 1 ADI NEVES ROCHA - DISSERTAÇÃO PPGEE 2014..pdf: 4213060 bytes, checksum: 41dbc9ec6203a02fc678bc1c878970dc (MD5) / Made available in DSpace on 2018-04-20T22:15:13Z (GMT). No. of bitstreams: 1 ADI NEVES ROCHA - DISSERTAÇÃO PPGEE 2014..pdf: 4213060 bytes, checksum: 41dbc9ec6203a02fc678bc1c878970dc (MD5) Previous issue date: 2014-08-08 / O objetivo do estudo apresentado nessa dissertação é analisar e comparar dois inversores fonte de tensão acionando uma máquina de indução hexafásica. as estruturas analisadas são: o conversor composto de seis braços possuindo dois dispositivos semicondutores por braço (12 chaves) e um conversor composto de três braços e nove dispositivos semicondutores (9 chaves). A estrutura composta por 12 chaves é a configuração padrão para acionamento de cargas hexafásicas . Analisando quanto ao aspecto da quantidade de chaves o conversor de 9 chaves apresenta uma evidente redução do número de componentes. Neste trabalho busca-se uma comparação mais fundamentada a partir da análise destas topologias com relação a outras características, tais como: (i) estrutura ou modo de conexão dos dispositivos com a descrição das limitações de cada estrutura; (ii) diferenças nas técnicas de modulação empregadas; (iii) níveis de corrente e tenção em cada um dos dispositivos que compõem a estrutura; (iv) análise do desempenho segundo a quantidade de perdas por condução e por chaveamento; (v) análise de desempenho quanto aos níveis de dispersão harmônica. Apesar da análise estar voltada para a comparação dos conversores, há uma descrição da máquina hexafásica modelada por decomposição vetorial e a aplicação de uma estratégia de controle no acionamento da máquina, utilzando a técnica de controle por fluxo rotórico. / The goal of the study presented in this thesis is to analyze and compare towo voltage source inverters driving a six-phase induction machine. The types of structures analyzed are: the converter of six legs having two semiconductor devices per leg (12 switches) and an inverter composed of three legs - (nine semiconductor devices 9 switches). The converter of 12 switches is the default configuration for driving six-phase loads. Analyzing the numbers of switches aspects, the 9 switches converter shows a clear reduction in the number of components. This paper seeks a more reasoned comparison from the analysis of these topologies with respect to other characteristics, such as: (i) structure or way of connecting devices to the description of the limitations of each structure; (ii) differences in the modulation techniques employed ; (iii) levels of current voltage in each of the devices of the structure; (iv) analysis of performance depending on the amount of conduction and switching losses; (v) performance analysis of the levels of harmonic distortion. Althought the analysis is focused on the comparison of the converters, there is a description of the six-phase machine modeled by vector decomposition and implementation of a control strategy to drive the machine using the rotor flux control technique.
6

Towards semi-automation of forestry cranes : automated trajectory planning and active vibration damping

Fodor, Szabolcs January 2017 (has links)
Forests represent one of the biggest terrestrial ecosystems of Earth, that can produce important raw renewable materials such as wood with the help of sun, air and water. To efficiently extract these raw materials, the tree harvesting process is highly mechanized in developed countries, meaning that advanced forestry machines are continuously used to fell, to process and to transport the logs and biomass obtained from the forests. However, working with these machines is demanding both mentally and physically, which are known factors to negatively affect operator productivity. Mental fatigue is mostly due to the manual operation of the on-board knuckleboom crane, which requires advanced cognitive work with two joystick levers, while the most serious physical strains arise from cabin vibrations. These vibrations are generated from knuckleboom crane vibrations as a result of aggressive manual operation. To enhance operator workload, well-being, and to increase productivity of the logging process, semi-automation functions are suggested, which are supervised automatic executions of specific work elements. Some of the related issues are addressed in the current thesis. Therefore, the content is divided into: (1) the design and development of a semi-automation function focused only on the base joint actuator (slewing actuator) of a knuckleboom crane, and (2) active vibration damping solutions to treat crane structure vibrations induced by the main lift cylinder (inner boom actuator). The considered reference machine is a downsized knuckleboom crane of a forwarder machine, which is used to pick up log assortments from a harvesting site. The proposed semi-automation function presented in the first part could be beneficial for operators to use during log loading/unloading scenarios. It consists from a closed-loop position control architecture, to which smooth reference slewing trajectories are provided by a trajectory planner that is automated via operator commands. The used trajectory generation algorithms are taken from conventional robotics and adapted to semi-automation context with proposed modifications that can be customizable by operators. Further, the proposed active vibration damping solutions are aimed to reduce vibrations of the knuckleboom crane excited by the inner boom actuator due to aggressive manual commands. First, a popular input shaping control technique combined with a practical switching logic was investigated to deal with the excited payload oscillations. This technique proved to be useful with a fixed crane pose, however it did not provide much robustness in terms of different link configurations. To tackle this problem an H2-optimal controller is developed, which is active in the pressure feedback-loop and its solely purpose is to damp the same payload oscillations. During the design process, operator commands are treated and explained from input disturbance viewpoint. All of the hypothesis throughout this thesis were verified with extensive experimental studies using the reference machine.
7

Single And Three Phase Power Factor Correction Techniques Using Scalar Control

Anand, A G Vishal 06 1900 (has links) (PDF)
No description available.
8

Imaging and Object Detection under Extreme Lighting Conditions and Real World Adversarial Attacks

Xiangyu Qu (16385259) 22 June 2023 (has links)
<p>Imaging and computer vision systems deployed in real-world environments face the challenge of accommodating a wide range of lighting conditions. However, the cost, the demand for high resolution, and the miniaturization of imaging devices impose physical constraints on sensor design, limiting both the dynamic range and effective aperture size of each pixel. Consequently, conventional CMOS sensors fail to deliver satisfactory capture in high dynamic range scenes or under photon-limited conditions, thereby impacting the performance of downstream vision tasks. In this thesis, we address two key problems: 1) exploring the utilization of spatial multiplexing, specifically spatially varying exposure tiling, to extend sensor dynamic range and optimize scene capture, and 2) developing techniques to enhance the robustness of object detection systems under photon-limited conditions.</p> <p><br></p> <p>In addition to challenges imposed by natural environments, real-world vision systems are susceptible to adversarial attacks in the form of artificially added digital content. Therefore, this thesis presents a comprehensive pipeline for constructing a robust and scalable system to counter such attacks.</p>

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