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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.
61

Internal promotion of Islamic banking offerings at a South African traditional bank: An action research study

Damon, Shameem January 2018 (has links)
Magister Commercii - MCom (Business and Finance) / This master's thesis report is a record of my action research study conducted at a traditional bank in South Africa. The report follows a narrative writing style. It contains my personal learnings and reflections. In it I record my practices aimed at promoting Islamic banking products of a traditional bank. In undertaking this action research, I employed interventions whereby I improved my own learning and behaviour through practice. This action research took place within the customer facing division of a national traditional bank in the Western Cape. While conducting my situational analysis, I found that front-line employees lacked knowledge and awareness about Islamic banking products, which negatively impacted their attitude and willingness to promote the Islamic banking offering. As the action research progressed, another concern was identified, namely, the lack of awareness of Islamic banking by customers. In order to guide activities that are directed at improving the behaviour of front-line employees and customers, I drew insights from the Theory of Planned Behaviour (TPB) by Icek Ajzen (1991) for my theoretical framework. Observations, interviews and interview schedules were used to collect data and continuously analysed using content analysis and univariate analysis for the respective data types. Evidence was generated by measuring the data against a standard of judgments as required for an action research project. This resulted in the identification of key factors that influence front-line employees' willingness to promote the Islamic banking products. These factors were their attitudes and perceived behavioural control. It was further identified that the lack of awareness by customers had a negative impact on their attitudes towards using the Islamic banking offering. Both issues were addressed, by following the cyclical approach of action research. In order to influence front-line employees' behaviour, with the support of the necessary stakeholders, I implemented internal marketing programmes such as training and development. To increase the level of customer awareness, I implemented activities directed at external customers such as brochures and poster displays within branches. The study finds that through my ethical and political practices, front-line employees were motivated and stakeholders actively participated in planning and executing interventions designed to improve the performance of Islamic banking sales. The practices implemented by myself, as an Islamic banking product champion, were identified as a key influence in the promotion of Islamic banking. I also identified that senior management and middle management influenced front-line employees' acceptance and implementation of internal marketing practices.
62

Power Management IC for Single Solar Cell

January 2015 (has links)
abstract: A single solar cell provides close to 0.5 V output at its maximum power point, which is very low for any electronic circuit to operate. To get rid of this problem, traditionally multiple solar cells are connected in series to get higher voltage. The disadvantage of this approach is the efficiency loss for partial shading or mismatch. Even as low as 6-7% of shading can result in more than 90% power loss. Therefore, Maximum Power Point Tracking (MPPT) at single solar cell level is the most efficient way to extract power from solar cell. Power Management IC (MPIC) used to extract power from single solar cell, needs to start at 0.3 V input. MPPT circuitry should be implemented with minimal power and area overhead. To start the PMIC at 0.3 V, a switch capacitor charge pump is utilized as an auxiliary start up circuit for generating a regulated 1.8 V auxiliary supply from 0.3 V input. The auxiliary supply powers up a MPPT converter followed by a regulated converter. At the start up both the converters operate at 100 kHz clock with 80% duty cycle and system output voltage starts rising. When the system output crosses 2.7 V, the auxiliary start up circuit is turned off and the supply voltage for both the converters is derived from the system output itself. In steady-state condition the system output is regulated to 3.0 V. A fully integrated analog MPPT technique is proposed to extract maximum power from the solar cell. This technique does not require Analog to Digital Converter (ADC) and Digital Signal Processor (DSP), thus reduces area and power overhead. The proposed MPPT techniques includes a switch capacitor based power sensor which senses current of boost converter without using any sense resistor. A complete system is designed which starts from 0.3 V solar cell voltage and provides regulated 3.0 V system output. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015
63

Power Management for Fuel Cell and Battery Hybrid Unmanned Aerial Vehicle Applications

January 2016 (has links)
abstract: As electric powered unmanned aerial vehicles enter a new age of commercial viability, market opportunities in the small UAV sector are expanding. Extending UAV flight time through a combination of fuel cell and battery technologies enhance the scope of potential applications. A brief survey of UAV history provides context and examples of modern day UAVs powered by fuel cells are given. Conventional hybrid power system management employs DC-to-DC converters to control the power split between battery and fuel cell. In this study, a transistor replaces the DC-to-DC converter which lowers weight and cost. Simulation models of a lithium ion battery and a proton exchange membrane fuel cell are developed and integrated into a UAV power system model. Flight simulations demonstrate the operation of the transistor-based power management scheme and quantify the amount of hydrogen consumed by a 5.5 kg fixed wing UAV during a six hour flight. Battery power assists the fuel cell during high throttle periods but may also augment fuel cell power during cruise flight. Simulations demonstrate a 60 liter reduction in hydrogen consumption when battery power assists the fuel cell during cruise flight. Over the full duration of the flight, averaged efficiency of the power system exceeds 98%. For scenarios where inflight battery recharge is desirable, a constant current battery charger is integrated into the UAV power system. Simulation of inflight battery recharge is performed. Design of UAV hybrid power systems must consider power system weight against potential flight time. Data from the flight simulations are used to identify a simple formula that predicts flight time as a function of energy stored onboard the modeled UAV. A small selection of commercially available batteries, fuel cells, and compressed air storage tanks are listed to characterize the weight of possible systems. The formula is then used in conjunction with the weight data to generate a graph of power system weight versus potential flight times. Combinations of the listed batteries, fuel cells, and storage tanks are plotted on the graph to evaluate various hybrid power system configurations. / Dissertation/Thesis / Masters Thesis Engineering 2016
64

Power Management Strategy of a Fuel Cell Hybrid Electric Vehicle with Integrated Ultra-Capacitor with Driving Pattern Recognition

January 2017 (has links)
abstract: The greenhouse gases in the atmosphere have reached a highest level due to high number of vehicles. A Fuel Cell Hybrid Electric Vehicle (FCHEV) has zero greenhouse gas emissions compared to conventional ICE vehicles or Hybrid Electric Vehicles and hence is a better alternative. All Electric Vehicle (AEVs) have longer charging time which is unfavorable. A fully charged battery gives less range compared to a FCHEV with a full hydrogen tank. So FCHEV has an advantage of a quick fuel up and more mileage than AEVs. A Proton Electron Membrane Fuel Cell (PEMFC) is the commonly used kind of fuel cell vehicles but it possesses slow current dynamics and hence not suitable to be the sole power source in a vehicle. Therefore, improving the transient power capabilities of fuel cell to satisfy the road load demand is critical. This research studies integration of Ultra-Capacitor (UC) to FCHEV. The objective is to analyze the effect of integrating UCs on the transient response of FCHEV powertrain. UCs has higher power density which can overcome slow dynamics of fuel cell. A power management strategy utilizing peak power shaving strategy is implemented. The goal is to decrease power load on batteries and operate fuel cell stack in it’s most efficient region. Complete model to simulate the physical behavior of UC-Integrated FCHEV (UC-FCHEV) is developed using Matlab/SIMULINK. The fuel cell polarization curve is utilized to devise operating points of the fuel cell to maintain its operation at most efficient region. Results show reduction of hydrogen consumption in aggressive US06 drive cycle from 0.29 kg per drive cycle to 0.12 kg. The maximum charge/discharge battery current was reduced from 286 amperes to 110 amperes in US06 drive cycle. Results for the FUDS drive cycle show a reduction in fuel consumption from 0.18 kg to 0.05 kg in one drive cycle. This reduction in current increases the life of the battery since its protected from overcurrent. The SOC profile of the battery also shows that the battery is not discharged to its minimum threshold which increasing the health of the battery based on number of charge/discharge cycles. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2017
65

Power-Performance Modeling and Adaptive Management of Heterogeneous Mobile Platforms​

January 2018 (has links)
abstract: Nearly 60% of the world population uses a mobile phone, which is typically powered by a system-on-chip (SoC). While the mobile platform capabilities range widely, responsiveness, long battery life and reliability are common design concerns that are crucial to remain competitive. Consequently, state-of-the-art mobile platforms have become highly heterogeneous by combining a powerful SoC with numerous other resources, including display, memory, power management IC, battery and wireless modems. Furthermore, the SoC itself is a heterogeneous resource that integrates many processing elements, such as CPU cores, GPU, video, image, and audio processors. Therefore, CPU cores do not dominate the platform power consumption under many application scenarios. Competitive performance requires higher operating frequency, and leads to larger power consumption. In turn, power consumption increases the junction and skin temperatures, which have adverse effects on the device reliability and user experience. As a result, allocating the power budget among the major platform resources and temperature control have become fundamental consideration for mobile platforms. Dynamic thermal and power management algorithms address this problem by putting a subset of the processing elements or shared resources to sleep states, or throttling their frequencies. However, an adhoc approach could easily cripple the performance, if it slows down the performance-critical processing element. Furthermore, mobile platforms run a wide range of applications with time varying workload characteristics, unlike early generations, which supported only limited functionality. As a result, there is a need for adaptive power and performance management approaches that consider the platform as a whole, rather than focusing on a subset. Towards this need, our specific contributions include (a) a framework to dynamically select the Pareto-optimal frequency and active cores for the heterogeneous CPUs, such as ARM big.Little architecture, (b) a dynamic power budgeting approach for allocating optimal power consumption to the CPU and GPU using performance sensitivity models for each PE, (c) an adaptive GPU frame time sensitivity prediction model to aid power management algorithms, and (d) an online learning algorithm that constructs adaptive run-time models for non-stationary workloads. / Dissertation/Thesis / Doctoral Dissertation Electrical Engineering 2018
66

Storage System for Harvested Energy in IoT Sensors

Alhuttaitawi, Saif January 2018 (has links)
This work presents an energy system design for wireless sensor networks (WSNs) after applying our design the WSN should theoretically have an infinite lifetime. Energy harvesting sources can provide suitable energy for WSN nodes and reduce their dependence on battery. In this project, an efficient energy harvesting and storage system is proposed. By using (two supercapacitors and four DC/DC converters with step up /step down capabilities) all of them controlled by Microcontroller via switches to consider the best way to save energy to keep the WSN alive as long as possible. The usage of supercapacitors as an energy buffer to supply the sensor components (microcontroller and radio) with energy it needs to work. We could control the energy flow according to a specific voltage levels in supercapacitors to guaranty the full functionality for WSN with minimizing the loss of energy, and that’s leads to long time life for the wireless sensor node WSN. Another important thing we find in our experiment that is the inner leakage of the supercapacitor and how it has a critical effect on how long it can serve our system with energy. This paper contains on two theoretical sections (Part one and part two) which are based on literature reviews, and one experimental section (Part three) based on experimental building the prototype, coding and testing.
67

Towards Energy Efficient Computing with Linux : Enabling Task Level Power Awareness and Support for Energy Efficient Accelerator

January 2013 (has links)
abstract: With increasing transistor volume and reducing feature size, it has become a major design constraint to reduce power consumption also. This has given rise to aggressive architectural changes for on-chip power management and rapid development to energy efficient hardware accelerators. Accordingly, the objective of this research work is to facilitate software developers to leverage these hardware techniques and improve energy efficiency of the system. To achieve this, I propose two solutions for Linux kernel: Optimal use of these architectural enhancements to achieve greater energy efficiency requires accurate modeling of processor power consumption. Though there are many models available in literature to model processor power consumption, there is a lack of such models to capture power consumption at the task-level. Task-level energy models are a requirement for an operating system (OS) to perform real-time power management as OS time multiplexes tasks to enable sharing of hardware resources. I propose a detailed design methodology for constructing an architecture agnostic task-level power model and incorporating it into a modern operating system to build an online task-level power profiler. The profiler is implemented inside the latest Linux kernel and validated for Intel Sandy Bridge processor. It has a negligible overhead of less than 1\% hardware resource consumption. The profiler power prediction was demonstrated for various application benchmarks from SPEC to PARSEC with less than 4\% error. I also demonstrate the importance of the proposed profiler for emerging architectural techniques through use case scenarios, which include heterogeneous computing and fine grained per-core DVFS. Along with architectural enhancement in general purpose processors to improve energy efficiency, hardware accelerators like Coarse Grain reconfigurable architecture (CGRA) are gaining popularity. Unlike vector processors, which rely on data parallelism, CGRA can provide greater flexibility and compiler level control making it more suitable for present SoC environment. To provide streamline development environment for CGRA, I propose a flexible framework in Linux to do design space exploration for CGRA. With accurate and flexible hardware models, fine grained integration with accurate architectural simulator, and Linux memory management and DMA support, a user can carry out limitless experiments on CGRA in full system environment. / Dissertation/Thesis / M.S. Electrical Engineering 2013
68

Unified Framework for Energy-proportional Computing in Multicore Processors: Novel Algorithms and Practical Implementation

January 2013 (has links)
abstract: Multicore processors have proliferated in nearly all forms of computing, from servers, desktop, to smartphones. The primary reason for this large adoption of multicore processors is due to its ability to overcome the power-wall by providing higher performance at a lower power consumption rate. With multi-cores, there is increased need for dynamic energy management (DEM), much more than for single-core processors, as DEM for multi-cores is no more a mechanism just to ensure that a processor is kept under specified temperature limits, but also a set of techniques that manage various processor controls like dynamic voltage and frequency scaling (DVFS), task migration, fan speed, etc. to achieve a stated objective. The objectives span a wide range from maximizing throughput, minimizing power consumption, reducing peak temperature, maximizing energy efficiency, maximizing processor reliability, and so on, along with much more wider constraints of temperature, power, timing, and reliability constraints. Thus DEM can be very complex and challenging to achieve. Since often times many DEMs operate together on a single processor, there is a need to unify various DEM techniques. This dissertation address such a need. In this work, a framework for DEM is proposed that provides a unifying processor model that includes processor power, thermal, timing, and reliability models, supports various DEM control mechanisms, many different objective functions along with equally diverse constraint specifications. Using the framework, a range of novel solutions is derived for instances of DEM problems, that include maximizing processor performance, energy efficiency, or minimizing power consumption, peak temperature under constraints of maximum temperature, memory reliability and task deadlines. Finally, a robust closed-loop controller to implement the above solutions on a real processor platform with a very low operational overhead is proposed. Along with the controller design, a model identification methodology for obtaining the required power and thermal models for the controller is also discussed. The controller is architecture independent and hence easily portable across many platforms. The controller has been successfully deployed on Intel Sandy Bridge processor and the use of the controller has increased the energy efficiency of the processor by over 30% / Dissertation/Thesis / Ph.D. Electrical Engineering 2013
69

Extending Efficiency in a DC/DC converter with automatic mode switching from PFM to PWM

January 2014 (has links)
abstract: Switch mode DC/DC converters are suited for battery powered applications, due to their high efficiency, which help in conserving the battery lifetime. Fixed Frequency PWM based converters, which are generally used for these applications offer good voltage regulation, low ripple and excellent efficiency at high load currents. However at light load currents, fixed frequency PWM converters suffer from poor efficiencies The PFM control offers higher efficiency at light loads at the cost of a higher ripple. The PWM has a poor efficiency at light loads but good voltage ripple characteristics, due to a high switching frequency. To get the best of both control modes, both loops are used together with the control switched from one loop to another based on the load current. Such architectures are referred to as hybrid converters. While transition from PFM to PWM loop can be made by estimating the average load current, transition from PFM to PWM requires voltage or peak current sensing. This theses implements a hysteretic PFM solution for a synchronous buck converter with external MOSFET's, to achieve efficiencies of about 80% at light loads. As the PFM loop operates independently of the PWM loop, a transition circuit for automatically transitioning from PFM to PWM is implemented. The transition circuit is implemented digitally without needing any external voltage or current sensing circuit. / Dissertation/Thesis / M.S. Electrical Engineering 2014
70

Distribuição de requisições em cluster de web services: uma abordagem flexível, dinâmica e transparente / Distibution of requests in cluster web services: an approach flexibel dynamic and transparent

Bruno Squizato Faiçal 28 May 2012 (has links)
Esta dissertação de mestrado propõe uma nova política de distibuição de requisições em cluster de web services, denominada Política Performance. Essa política provê uma distribuição transparente, flexível e dinâmica das requisições na plataforma em que é executada. Um estudo sistemático também é realizado para analisar a qualidade dos índices de carga empregados no contexto de web services e propõe um novo índice capaz de representar fielmente o desempenho dos web services e encapsular a complexidade estrutural da plataforma. Também é proposto em Módulo Gerenciador de Energia capaz de prover sustentabilidade à plataforma, reduzindo o consumo de energia elétrica sem prejudicar a alta confiabilidade na distribuição das requisições e com baixo impacto no tempo médio de resposta. Os estudos experimentais realizados neste trabalho mostraram que a Política Performance permitiu um melhor desempenho no atendimento das requisições realizadas à plataforma. EStes resultados referem-se a um desempenho superior a 70% no tempo médio de resposta, quando comparado ao desempenho demosntrado pela política padrão do Mod_cluster. O Módulo Gerenciador de Energia proporcionou uma redução de aproximadamente 30% no consumo de energia da plataforma mantendo a alta confiabilidade na distribuição das requisições / The Master\'s dissertation proposes a new for distribution of requests in cluster of web services, named policy Performance. This policy provides a transparent flexible and dynamic distribution of requests on the plataform. A systematic study is also conducted to example the quality of load indices used in the context of web services., and proposes a new index that accurately represent the performance of web services and encapsulate the complexity structural of the plataform. Also proposed is an Energy Manager Module capable of providing sustainability to the plataform, reducing power consumption without sacrificing high reliability in the distribution of request and low impact on the average response time. Our main results show that policy Performance has a better performance in handling requests sent to the plataform. Our results show a gain of performance higher than 70% in average responswetime when compared to the perormance demonstrated by the defaut policy Mod_cluster. The Power Manager Module reduced byapproximately 30% the energy consumption of the plataform even keeping the high reliability in the distribution of requests

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