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(121 - 140 of 392)
Pages
- Title
- Study of a selenium cell
- Creator
- Newlander, R. A.
- Date
- 2009, 1918
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofseleniumc00newl
Thesis (B.S.)--Armour Institute of Technology; Bibliography : leaf 33
- Title
- Speed-time curve study of electric railway load conditions
- Creator
- Banning, Thomas A., Jr
- Date
- 2009, 1907
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/speedtimecurvest00bann
Thesis (B.S.)--Armour Institute of Technology
- Title
- OPTIMAL DESIGN OF PERMANENT MAGNET SYNCHRONOUS MACHINES BASED ON MAGNETIC FIELD DISTRIBUTION ASSESSMENT AND PERFORMANCE ANALYSIS
- Creator
- Jiang, Yong
- Date
- 2015, 2015-05
- Description
-
The detailed magnetic field distribution of a permanent magnet electric motor is very important for the accurate prediction of performance...
Show moreThe detailed magnetic field distribution of a permanent magnet electric motor is very important for the accurate prediction of performance parameters such as back electromotive force (back-EMF), rotor and stator losses, winding inductances, noise and vibration, torque profiles, etc. Although finite element analysis is a good option for accurately calculating magnetic field distribution in electrical machines, it is typically timeconsuming and does not provide closed form solutions. Alternatively, analytical calculation of magnetic field distribution can be conducted in Fourier series, which is more suitable for a design tool to predict the motor performance. This dissertation presents a novel numerical technique for calculating exact magnetic field distribution in the air gap of a surface mounted permanent magnet machine. This solution can be obtained via a two-dimension analytical solution with Laplacian and quasi-Poisonian equations, assuming that the iron is infinitely permeable and the air gap is slotless. Slot effects can be added in the model by using relative air gap permeance calculated by the conformal transformation of slot geometry. This technique is constructed by multiplying the relative permeance function expressed in an infinite Fourier series with the distribution of magnetic field in the slotless air gap. This method shows a very good alignment with finite element method for a surface mounted permanent magnet machine with radial magnetization. It can also be extended to calculating magnetic field distribution of interior permanent magnet motors including consideration of magnetic saturation, crosssaturation between d-axis and q-axes, affecting both inductances and flux linkages, as well as localized effects due to rotor bridges. Furthermore, this approach can be used to create a closed-form solution, which is the first step towards inverse modeling of electric machines. This is a complete paradigm shift in the design process for electric machines, which can reduce the time taken to design an electric machine, while reducing the active material content to make them power dense with significant reduction in cost. Furthermore, availability of analytical description of the field components will aid in the designer’s ability to distinguish between the control and magnetic design aspects.
Ph.D. in Electrical and Computer Engineering, May 2015
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- Title
- SRAM DESIGN BASED ON CNFET: A DISCUSSION ON CIRCUIT, PARAMETER AND DIAMETER VARIATION
- Creator
- Yu, Zhiyuan
- Date
- 2011-05-05, 2011-05
- Description
-
This thesis describes the effort in designing SRAMs based on Carbon Nanotube Field Effect Transistor (CNFET), and covers several aspects...
Show moreThis thesis describes the effort in designing SRAMs based on Carbon Nanotube Field Effect Transistor (CNFET), and covers several aspects including circuit structure, parameters, layout and the detection of diameter variation. It aims at providing a primitive reference on the topic of employing CNFETs in realistic SRAM design. In this thesis, we propose a guideline for choosing appropriate transistor ratios with respect to differently selected diameters in a conventional 6-T SRAM. Constraints of transistor ratios are established, followed by the optimization of the ratios regarding Static Noise Margin (SNM) and Read Noise Margin (RNM) of the cell. With the optimal parameters, the CNFET cell can achieve 41.41% and 1.26% improvement over traditional CMOS in SNM and RNM, respectively. Then we propose a column-based monitoring circuit which is capable of detecting variation in the diameter of tubes. It is grounded on a novel layout of the 6-T SRAM based on CNFET, which assigns all cells in a column of the SRAM array to the same group of Carbon Nanotubes (CNTs). This monitor outputs a digital signal indicating the impact of diameter variation on delay of the circuit, and enables further mitigation of the variation. Alternatively, a new 6-T SRAM cell structure is proposed for optimizing the performance of the cell at very-low or sub-threshold supply voltages. Compared with a traditional 6-T cell, simulation results show that the reading and writing delay have been improved by more than 80% and 75% at 0.4V supply voltage, respectively. It achieves PDP reduction of 70% and 91% for reading and writing operations.
M.S. in Electrical Engineering, May 2011
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- Title
- SUPPORT VECTOR MACHINE BASED CLASSIFICATION FOR TRAFFIC SIGNS AND ULTRASONIC FLAW DETECTION
- Creator
- Virupakshappa, Kushal
- Date
- 2015, 2015-12
- Description
-
The use of machine learning techniques for the advanced signal and image processing applications is gaining importance due to performance...
Show moreThe use of machine learning techniques for the advanced signal and image processing applications is gaining importance due to performance increases in accuracy and robustness. Support Vector Machine (SVM) is a machine learning method used for classification and regression analysis of complex real-world problems that may be difficult to analyze theoretically. In this dissertation, the use of SVM for the application of ultrasonic flaw detection and traffic sign classification has been investigated and new methods are introduced. For traffic sign detection, Bag of visual Words technique has been implemented on Speeded Up Robust Feature (SURF) descriptors of the traffic signs and later the sturdy classifier SVM is used to categorize the traffic signs to its respective groups. Experimental results demonstrate that the proposed method of implementation can reach an accuracy of 95.2 % . For ultrasonic aw detection, subband decomposition filters are used to generate the necessary feature vectors for the SVM classifier. Experimental results, using A-scan data measurements from a steel block, show that a very high classification accuracy can be achieved. Robust performance of the classifier is due to proper selection of frequency-diverse feature vectors and successful training. SVM has also been used for regression analysis to locate and amplify the aw by suppressing the clutter noise. The results show that the use of SVM is reliable and achievable for both the applications.
M.S. in Electrical Engineering, December 2015
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- Title
- DEVELOPMENT OF COMPUTER-AIDED DIAGNOSIS METHODS IN MAMMOGRAPHY
- Creator
- Wang, Juan
- Date
- 2015, 2015-12
- Description
-
Computer-aided diagnosis (CAD) is developed as a diagnostic aid to provide a “second opinion” in diagnosis of breast cancer in early stage....
Show moreComputer-aided diagnosis (CAD) is developed as a diagnostic aid to provide a “second opinion” in diagnosis of breast cancer in early stage. Clustered microcalcifications (MCs) can be an important early sign of breast cancer. The goal of this work is to develop automatic CAD methods in mammography for breast cancer. Its contribution consists of both development of machine learning algorithms and study of related issues in detection and diagnosis of breast cancer with clustered MCs. First, a bi-thresholding scheme is proposed for reduction of false-positives (FPs) associated with linear structures in MC detection. An unified classifier with dummy variable modeling is further developed to reduce the FPs caused by both linear structures and MC-like noise patterns. It is demonstrated that both of the proposed algorithms can reduce FPs in MC detection, and thus, improve the detection accuracy significantly. Second, a spatial density modeling approach is investigated to quantify the spatial distribution of the MCs in a cluster when the MC detection is inaccurate. A spatial density function (SDF) is defined such that the extracted features are more robust to the presence of FPs and false-negatives (FNs) in MC detection. The results show that the features extracted from the SDF can achieve better class separation while being robust to the variations in MC detection when compared with those extracted from a traditional region-based method. Third, a retrieval-boosted approach is studied to discriminate between the benign and malignant MC lesions. A retrieval strategy is proposed to boost the classification performance by taking into account the similarity both in image features and in pathology. An adaptive Adaboost classifier, which can be adapted to the retrieved cases at a low computational cost, is applied to demonstrate the benefit of the retrieval strategy. The results show that the retrieval-boosted approach can signifishow that the features extracted from the SDF can achieve better class separation while being robust to the variations in MC detection when compared with those extracted from a traditional region-based method. Third, a retrieval-boosted approach is studied to discriminate between the benign and malignant MC lesions. A retrieval strategy is proposed to boost the classification performance by taking into account the similarity both in image features and in pathology. An adaptive Adaboost classifier, which can be adapted to the retrieved cases at a low computational cost, is applied to demonstrate the benefit of the retrieval strategy. The results show that the retrieval-boosted approach can significantly outperform its baseline classifier and that inclusion of pathology information in the retrieval can further improve the classification accuracy. Fourth, the perceptual similarity of MC lesions by radiologists is studied. The issues investigated include the degree of variability in the similarity ratings, the impact of this variability on agreement between readers in retrieval of similar lesions, and the factors contributing to the readers’ similarity ratings. The results indicate that perceptually similar lesions could be of diagnostic value in diagnosis for clustered MCs. Fifth, the feasibility of modeling the perceptual similarity of MC lesions is investigated. A support vector regression (SVR) is applied to model the perceptual similarity of clustered MCs, and a feature saliency analysis derived from SVR is used to determine the most relevant image features among a large set of candidate features. The results demonstrate that the relevant features are consistent in radiologists’ similarity ratings among different MC lesions, indicating that the perceptual similarity of MC lesions by radiologists can be effectively modeled. Finally, whether retrieval of similar images can effectively assist radiologists in diagnosis of clustered MCs is investigated. A retrieval system for relevant images is designed by considering both perceptually similar image features and the likelihood of malignancy of the lesion under consideration. An observer study is conducted to evaluate the diagnostic value of the proposed retrieval system. The results indicate that the proposed retrieval system has the potential to improve the reader’s ability in diagnosis of breast cancer with clustered MCs.
Ph.D. in Electrical Engineering, December 2015
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- Title
- A study of neutral currents in star connected three-phase alternators and transformers
- Creator
- Kaiser, Everett Dee, Myers, Frank Edward
- Date
- 2009, 1911
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/studyofneutralcu00kais
Thesis (B.S.)--Armour Institute of Technology; Includes bibliographical references and index
- Title
- POLARIZATION INDUCED BY A TERAHERTZ ELECTRIC FIELD ON A CONDUCTIVE PARTICLE
- Creator
- Shen, Tao
- Date
- 2013, 2013-05
- Description
-
Interactions of an electromagnetic wave with an object of dimensions small compared to the wavelength can often be accounted for by...
Show moreInteractions of an electromagnetic wave with an object of dimensions small compared to the wavelength can often be accounted for by considering the dipole moments, which are effective in explaining the scattering characteristics in the frequency range referred to as the Rayleigh region. Dielectric functions derived from polarization processes due to molecular orientation or bound charge displacements have been employed over the years to account for the scattering properties of particles. In the presence of mobile charges, bulk conductivity may be incorporated with a complex dielectric function to explain the peak in absorption near the plasma frequency exhibited by metallic particles in the optical region. With the current interest in nanostructures, an investigation of the electromagnetic properties of a conductive particle with attention given to space-charge effects would appear timely. This can be accomplished by coupling the transport equations of the charge carriers to the Maxwell’s equations. Results of computations performed for elementary structures such as plates and particles revealed the screening of the internal field while dispersion and absorptions effects are shown by the complex dipole moments. To gain insight into the nature of charge-wave interactions, results based on quasi-static formulation for the electric field will be compared with those based on full-wave analysis, with special attention given to the charge and current distributions within the structure. By consideration of the physical process of charge carrier motion and lattice polarization, the equivalent circuit model for a conductive nanoparticle in the terahertz frequency range is developed. All circuit elements are of electrical nature and can be directly expressed in terms of material parameters. The equivalent circuit can serve as the basis of analysis for composite structures and aggregates of which the conductive nanoparticle is a constituent.
PH.D in Electrical Engineering, May 2013
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- Title
- VERIFICATION OF LARGE-SCALE ON-CHIP POWER GRIDS
- Creator
- Xiong, Xuanxing
- Date
- 2013, 2013-05
- Description
-
As technology scaling continues, the performance and reliability of integrated circuits become increasingly susceptible to power supply noises...
Show moreAs technology scaling continues, the performance and reliability of integrated circuits become increasingly susceptible to power supply noises, such as IR drops and Ldi/dt noises in the on-chip power grids. Reduced supply voltage levels in the grid can increase the gate delay, leading to timing violations and logic failures. In order to ensure a reliable chip design, it is critical to verify that the power grid is robust, i.e., the power supply noises are acceptable for all possible runtime situations. Hence, power grid verification has become an indispensable step in modern design flow of integrated circuits. Nowadays, it is common practice to verify power grids by simulation. Typically, an equivalent RC/RLC circuit model of the grid is extracted from the layout, and designers perform simulations to evaluate the power supply noises based on the current waveforms drawn by the circuit. As power grid simulation can only be performed after the circuit design is done, vectorless power grid verification has been introduced to enable early power grid verification with incomplete current specifications, so that the power grid design can be better tuned and optimized at early design stages, thus reducing the design time. Due to the increasing complexity of modern chips, power grid verification has become very challenging. The broad goal of this dissertation is to explore efficient algorithms for verifying large-scale on-chip power grids. Specifically, we study parallel power grid transient simulation, vectorless steady-state verification and vectorless transient verification. Parallel forward and back substitution algorithms are designed for efficient transient simulation; a set of novel algorithms are developed to incrementally improve the runtime efficiency of vectorless steady-state verification; and an efficient approach is proposed for vectorless transient verification with novel constraint setting.
PH.D in Electrical Engineering, May 2013
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- Title
- SIMULATION AND DEVELOPMENT OF A CLINICAL ANALYZER-BASED IMAGING SYSTEM
- Creator
- Majidi, Keivan
- Date
- 2013, 2013-12
- Description
-
The analyzer-based phase-sensitive X-ray imaging method (ABI) is emerging as a potential alternative to conventional radiography. ABI...
Show moreThe analyzer-based phase-sensitive X-ray imaging method (ABI) is emerging as a potential alternative to conventional radiography. ABI simultaneously generates a number of planar images containing information about scattering, refraction and absorption properties of the object. These parametric images are acquired by sampling the angular intensity profile (AIP) of an X-ray beam passing through the object at different positions of the analyzer crystal. Like many of the modern imaging techniques, ABI is a computed imaging method (meaning that the images are calculated from raw data). Therefore, the noise in ABI depends on the imaging conditions such as source flux, number of the analyzer positions, and the analyzer positions themselves as well as on the estimation method of the parameters. In the first part of this thesis, we use the Cramer-Rao lower bound to quantify the noise in ABI images and then investigate the effect of different analyzer-sampling strategies on this bound. The CRLB is the minimum bound for the variance of an unbiased estimator and defines the best noise performance that one can obtain regardless of which estimation method is used to estimate ABI parametric images. We will then use this bound to evaluate three ABI methods: Multiple-Image Radiography (MIR), Diffraction Enhanced Imaging (DEI) and Scatter Diffraction Enhanced Imaging (S-DEI). The proposed methodology can be used to evaluate any other ABI parametric image estimation technique. Synchrotron radiation has been the main source for experimental ABI and developing its methodologies, therefore the ABI application to clinical imaging has been very limited. It is inevitable to use conventional X-ray sources for ABI in order to utilize xii the technique in the clinical applications, however, due to the limited intensity of these sources and their finite source size, developing such systems is very challenging. In the second part of this thesis, we use computer simulations to understand the above challenges better. We measure the properties of this imaging system such as flux and point-spread function for various design parameters and discuss how to find an “optimal” setup based on these properties. The optimality of an imaging setup depends on the specific application that one wants to perform using the system; however, the results and discussions in this section layouts a design procedure for clinical ABI systems. In the last part of this thesis we review the steps we took in the Advanced X-ray Imaging Laboratory (AXIL) toward developing a clinical ABI system.
PH.D in Electrical Engineering, December 2013
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- Title
- ROBUST OPTIMIZATION OF UNIT COMMITMENT PROBLEM WITH RENEWABLE RESOURCES AND ELECTRICAL ENERGY STORAGE
- Creator
- Kashyap, Prakash
- Date
- 2016, 2016-12
- Description
-
The Chinese proverb |\To be uncertain is to be uncomfortable, but to be cer- tain is to be ridiculous" |mention in the preface of the book...
Show moreThe Chinese proverb |\To be uncertain is to be uncomfortable, but to be cer- tain is to be ridiculous" |mention in the preface of the book Robust Optimization by Aharon Ben-Tal, Laurent El Ghaoui and Arkadi Nemirovski, truly capture the cer- tainty of uncertainty in every walk of life. However, it is human endeavor to manage uncertainty by properly engineered system. Power system is no exception. Uncer- tainty with load forecasting and contingencies such as generator and/or transmission line outages impose reliability and security issue with power system operation. In wholesale market, tools like spinning reserve and non-spinning reserve are used by ISO/RTO to mitigate severe consequences of such uncertainties. With increased share of highly volatile renewable energy resources such as wind and solar power, price-based demand response and electric vehicle charging station, uncertainty in power system operation is going to be further aggravated. A scenario based stochastic approach instead of system reserve based deterministic approach is considered another solution to the problem. However, scenario based stochastic solution may miss some critical scenarios. Secondly, we may need a large number of scenarios to get a su ciently reliable solution. In recent years, robust optimization based security constrained economic dis- patch (SCED) and security constrained unit commitment (SCUC) have been explored by several researchers. This thesis explores implementation of robust optimization for secure and economical operation of power system in presence of renewable energy resources (RES) and electrical energy storages (EES).
M.S. in Electrical Engineering, December 2016
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- Title
- VALUE OF BATTERY STORAGE SYSTEM IN THE FEREQUENCY REGULATION MARKETS OF PJM AND CAISO
- Creator
- Khorsand, Shervin
- Date
- 2017, 2017-05
- Description
-
With an increasingly urgent need to decrease our utilization of fossil fuels, renewable power sources such as wind and solar are being...
Show moreWith an increasingly urgent need to decrease our utilization of fossil fuels, renewable power sources such as wind and solar are being incorporated in the electricity grid. However, these sources lack the conventional reliability that fossil fuels, such as natural gas, and oil have previously provided. The solution lies in energy storage, and exactly why battery storage systems are the means for renewable energy sources to become truly transformative and revolutionize the energy market. In the first part of this paper, a comprehensive summary of the different types of energy storage technologies have been provided along with their features, which make each technology suitable for different applications. Next, a detailed chapter focused on battery storage systems and their properties is provided along with the ancillary services they offer as sustenance and support sources integrated in the electric grid. These service are integral to the continuous transmission of power to consumers, and necessary for the supply to meet end-user demands. Among these service include frequency regulation as well as spinning reserve services, the latter being important under emergency condition following a power disruption. Regulation services however, are constantly required for grid stability and reliability, which is why this service was selected for further market analysis. For this market analysis, the California Independent Systems Operator (CAISO), and PJM Interconnection (PJM) were selected as both have extensive regulation markets and two of the major power suppliers nationwide. The main question in conducting this analysis was to determine which market would be more attractive and profitable for a potential regulation provider to invest using a Lithium ion battery. The Regulation Market Clearing Price (RMCP) for each market was extracted from the operators’ annual reports over the last six years and used as measure of investor revenue. The Levelized Cost of Energy Storage was computed for a Lithium ion battery with certain characteristics, and the investor revenue was calculated as a percent of the LCOE. Our analysis showed that although CAISO’s regulation market is showing growth in the recent years, especially in 2016 during the period of increased regulation requirement, PJM has had consistently higher RMCP values, which means the investor revenue would be higher in PJM. Our calculations show that investing a Lithium ion battery with a power rating of 10MW, and energy capacity of 5 MWh, operating at 89% efficiency for 4.8 cycles per day for 350 days in PJM is going to be economically a much smarter choice.
M.S. In Electrical Engineering, May 2017
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- Title
- NOVEL AUTONOMOUS DRONE ARCHITECTURE WITH WIRELESS NETWORK USING REAL-TIME SIGNAL PROCESSING AND MOBILE DEVICE FOR ASSISTING RESCUE SERVICE
- Creator
- Kim, Heekyung
- Date
- 2015, 2015-12
- Description
-
The Autonomous Drone can be economically one of the effective and efficient tools for disaster management. In this research, for disaster...
Show moreThe Autonomous Drone can be economically one of the effective and efficient tools for disaster management. In this research, for disaster relief operations, Autonomous Drone Architecture with wireless network provides disaster assistance by tracking a survivor and getting important information from multiple sensors on it. [1] ADWN architecture consist of two different platforms, Raspberry pi and Arduino, to separate their roles of the process, which are like collecting the sensor data and sending control signal from Raspberry Pi to Arduino. Once gathering data from sensors and transmitting it to Raspberry Pi, it can analysis by applying signal processing formula in real-time. [2] In this case, Raspberry Pi can multitask process and use various language libraries such as OpenCV, Python, and others. Also, Raspberry Pi can add lots of sensors, a camera, and other kinds of boards. Using these features, transmitted data can be processed in real-time and be sending to Arduino to control with reduced error. These strength of ADWN architecture provides scalability and high availability to control drone as a disaster assistance.
M.S. in Electrical Engineering, December 2015
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- Title
- MODELING, ANALYSIS AND DESIGN OF MULTI-CHANNEL BONDING FOR IEEE 802.11 WLANS
- Creator
- Khairy, Sami
- Date
- 2016, 2016-12
- Description
-
The aim of this dissertation is to study the performance of distributed and opportunistic multi-channel bonding protocol in IEEE 802.11ac...
Show moreThe aim of this dissertation is to study the performance of distributed and opportunistic multi-channel bonding protocol in IEEE 802.11ac WLANs, and design channel bonding strategies to efficiently utilize the available spectrum. To this end, we first develop an analytical framework to study the throughput performance of WLANs with co-existing ac users and legacy users, characterizing the contentions among ac and legacy users in both primary and secondary channels. By modeling the transmissions of legacy users and ac users with and without bonding as a twolevel renewal process, the channel bonding probability of ac users in each secondary channel can be derived. Based on the bonding probability, MAC throughput of ac and legacy users can be analyzed respectively. Our analysis show that in a homogeneous multi-channel WLAN where only ac users are present, the contention probability of ac users is the same as that in a single channel with the same number of users; and in a heterogeneous WLAN with both ac and legacy users, an ac user can achieve a higher throughput than a legacy user, although the overall throughput decreases due to the increased contention level imposed by ac users in secondary channels. Based on the analysis, we further propose a channel selection strategy for ac users to select the best primary channel, in order to mitigate the contentions in the network and attain the maximal throughput. Analytical results show that primary channel selection is indifferent in a homogeneous network, whereas in a heterogeneous network, ac users should select the least congested channel as the primary channel to attain the maximal throughput. To evaluate the performance of a multi-channel WLAN, we develop an event-driven simulator based on network simulator-3 (NS-3). Extensive simulations validate our analyses and the efficiency of the proposed channel selection strategy.
M.S. in Electrical Engineering, December 2016
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- Title
- SELF-POWERED DC SOLID STATE CRICUIT BREAKERS
- Creator
- Miao, Zhenyu
- Date
- 2015, 2015-07
- Description
-
Dc power systems are better system solutions than ac power systems in application areas such as data centers, electric ships and dc micro...
Show moreDc power systems are better system solutions than ac power systems in application areas such as data centers, electric ships and dc micro-grids. But the lack of fast and cost effective dc circuit breakers impedes the development and application of dc power systems. This thesis introduces a new type of self-powered dc solid state circuit breakers (SSCB) which are inactive during normal operation but can be triggered and powered up by a short circuit event. The design of a unidirectional solid state circuit breaker and a bidirectional solid state breaker are proposed. The solid state circuit breakers are consisted of normally-on SiC JFETs as main power switches and gate drivers featuring fast start-up forward-flyback converters. The operation principles of the circuit breakers are analyzed in details. Prototypes are built and verified in short circuit tests. The circuit breaker prototypes can interrupt short circuit currents up to 180 amperes at a dc bus voltage of 400 volts within 1 microsecond. Chapter 1 introduces the safety considerations of dc power systems, characteristics of conventional ac circuit breakers, and the development of solid state circuit breakers. Chapter 2 introduces the concepts of the proposed self-powered SSCBs and operation principle of a fast start-up forward-flyback converter. Chapter 3 introduces the schematic design of a unidirectional self-powered SSCB, its operation principle and experimental results. Chapter 4 introduces the schematic design of a bidirectional self-powered SSCB, its operation principle and experimental results. Chapter 5 concludes the thesis and looks forward to future work.
M.S. in Electrical Engineering, July 2015
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- Title
- SECURE DATA SERVICE OUTSOURCING IN CLOUD COMPUTING
- Creator
- Wang, Cong
- Date
- 2012-04-22, 2012-07
- Description
-
Cloud computing economically enables a fundamental paradigm of data service outsourcing, which provides lower up-front capital costs and less...
Show moreCloud computing economically enables a fundamental paradigm of data service outsourcing, which provides lower up-front capital costs and less hands-on management. However, outsourcing data services to the commercial public cloud deprives customers' control over the systems that manage their data, raising security and privacy as the primary obstacles to the adoption of the cloud. To address these challenges, in this dissertation we explore the problem of secure and privacy-assured data service outsourcing in cloud computing. We aim at deploying the most fundamental data services including data storage, search, and sharing on the commercial public cloud, with built-in security and privacy assurance as well as high level service performance, usability, and scalability. Our contributions are as follows: Firstly, we focus on privacy-preserving secure cloud storage auditing to maintain strong storage correctness guarantee, given the di culty that data les are no longer locally possessed by data owners. We rst develop a random-masking sampling approach to allow a third party auditor to perform on-demand privacy-preserving storage correctness auditing on behalf of data owners, without violating owners' data privacy. For storage correctness assurance with data dynamics, we further investigate a novel sequence-enforced Merkle Hash Tree and manipulate it with the random sampling approach to support fully dynamic data operations. Secondly, we focus on privacy-assured and e ective cloud data search services with strong privacy-assurance, while enjoying high service-level performance inherently demanded by the large number of data users and huge amount data les. We rst investigate a widely applicable fuzzy/similarity keyword search problem, and develop a brand new symbol-based trie-traverse searching approach, where transformed fuzzy keywords extracted from data les are stored using a multi-way tree structure, while protecting keyword privacy. To enable search result relevance ranking, we further investigate secure ranked search, which facilitates e cient server-side result ranking without leaking any keyword related information. Thirdly, we study how to enable scalable and owner-controlled cloud data sharing services, given the challenge that data no longer resides on owners' trusted domain. We rst associate data with a set of meaningful attributes, use logical composition of attributes to re ect ne-grained data access, and enforce owner's control via attribute-based encryption. For the inherent scalability requirement of cloud system, we further leverage the cloud as a mediated proxy, to which data owners can delegate most cumbersome data/user management workload, without a ecting the underlying data con dentiality.
Ph.D. in Electrical Engineering, July 2012
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- Title
- Comparative tests of integrating wattmeters
- Creator
- Schaedlich, Hans, Cutler, E. W.
- Date
- 2009, 1906
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/comparativetests00scha
Thesis (B.S.)--Armour Institute of Technology
- Title
- Complete tests of the Willis straightline watthour meter and the Columbia shunted astatic watthour meter
- Creator
- Goldberg, I, Sackheim, S
- Date
- 2009, 1911
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/completetestsofw00gold
Thesis (B.S.)--Armour Institute of Technology, 1911 Bibliography: leaf 73 B.S. in...
Show morehttp://www.archive.org/details/completetestsofw00gold
Thesis (B.S.)--Armour Institute of Technology, 1911 Bibliography: leaf 73 B.S. in Electrical Engineering, 1911
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- Title
- Electrification project the Illinois Central Railroad Company suburban service at Chicago, Ill.
- Creator
- Simpson, Tracy W.
- Date
- 2009, 1909
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/electrificationp00simp
Thesis (B.S.)--Armour Institute of Technology
- Title
- The electrification project of the Chicago suburban service of Chicago, Burlington & Quincy R.R.
- Creator
- Downton, Percival G.
- Date
- 2009, 1914
- Publisher
- Armour Institute of Technology
- Description
-
http://www.archive.org/details/electrificationp00down
Thesis (B.S.)--Armour Institute of Technology, 1914 B.S. in Electrical Engineering, 1914