Digital Commons Network^™

On The Viability Of Quantitative Assessment Methods In Software Engineering And Software Services, Joseph D. Lucente

Electronic Theses and Dissertations

IT help desk operations are expensive. Costs associated with IT operations present challenges to profit goals. Help desk managers need a way to plan staffing levels so that labor costs are minimized while problems are resolved efficiently. An incident prediction method is needed for planning staffing levels. The potential value of a solution to this problem is important to an IT service provider since software failures are inevitable and their timing is difficult to predict. In this research, a cost model for help desk operations is developed. The cost model relates predicted incidents to labor costs using real help desk …

Fail-Safe Test Generation Of Safety Critical Systems, Salwa Elakeili

Electronic Theses and Dissertations

This dissertation introduces a technique for testing proper failure mitigation in safety critical systems. Unlike other approaches which integrate behavioral and failure models, and then generate tests from the integrated model, we build safety mitigation tests from an existing behavioral test suite, using an explicit mitigation model for which we generate mitigation paths which are then woven at selected failure points into the original test suite to create failure-mitigation tests (safety mitigation test).

Synchrophasor Sensing And Processing Based Smart Grid Security Assessment For Renewable Energy Integration, Huaiguang Jiang

Electronic Theses and Dissertations

With the evolution of energy and power systems, the emerging Smart Grid (SG) is mainly featured by distributed renewable energy generations, demand-response control and huge amount of heterogeneous data sources. Widely distributed synchrophasor sensors, such as phasor measurement units (PMUs) and fault disturbance recorders (FDRs), can record multi-modal signals, for power system situational awareness and renewable energy integration.

An effective and economical approach is proposed for wide-area security assessment. This approach is based on wavelet analysis for detecting and locating the short-term and long-term faults in SG, using voltage signals collected by distributed synchrophasor sensors.

A data-driven approach for fault …

Microgrid Optimal Scheduling Considering Impact Of High Penetration Wind Generation, Abdulaziz Furreh Alanazi

Electronic Theses and Dissertations

The objective of this thesis is to study the impact of high penetration wind energy in economic and reliable operation of microgrids. Wind power is variable, i.e., constantly changing, and nondispatchable, i.e., cannot be controlled by the microgrid controller. Thus an accurate forecasting of wind power is an essential task in order to study its impacts in microgrid operation. Two commonly used forecasting methods including Autoregressive Integrated Moving Average (ARIMA) and Artificial Neural Network (ANN) have been used in this thesis to improve the wind power forecasting. The forecasting error is calculated using a Mean Absolute Percentage Error (MAPE) and …

Assessment Of Normal Knee Kinematics Using High-Speed Stereo-Radiography System, Vasiliki Kefala

Electronic Theses and Dissertations

The measurement of dynamic joint kinematics in vivo is important in order to understand the effects of joint injuries and diseases as well as for evaluating the treatment effectiveness. Quantification of knee motion is essential for assessment of joint function for diagnosis of pathology, such as tracking and progression of osteoarthritis and evaluation of outcome following conservative or surgical treatment. Total knee arthroplasty (TKA) is an invasive treatment for arthritic pain and functional disability and it is used for deformed joint replacement with implants in order to restore joint alignment. It is important to describe knee kinematics in healthy individuals …

Spontaneous Facial Behavior Computing In Human Machine Interaction With Applications In Autism Treatment, Seyedmohammad Mavadati

Electronic Theses and Dissertations

Digital devices and computing machines such as computers, hand-held devices and robots are becoming an important part of our daily life. To have affect-aware intelligent Human-Machine Interaction (HMI) systems, scientists and engineers have aimed to design interfaces which can emulate face-to-face communication. Such HMI systems are capable of detecting and responding upon users' emotions and affective states. One of the main challenges for producing such intelligent system is to design a machine, which can automatically compute spontaneous behaviors of humans in real-life settings. Since humans' facial behaviors contain important non-verbal cues, this dissertation studies facial actions and behaviors in HMI …

Electroencephalogram Based Causality Graph Analysis In Behavior Tasks Of Parkinson’S Disease Patients, Abdulaziz Saleh Almalaq

Electronic Theses and Dissertations

Electroencephalographic (EEG) signals of the human brains represent electrical activities for a number of channels recorded over a the scalp. The main purpose of this thesis is to investigate the interactions and causality of different parts of a brain using EEG signals recorded during a performance subjects of verbal fluency tasks. Subjects who have Parkinson's Disease (PD) have difficulties with mental tasks, such as switching between one behavior task and another. The behavior tasks include phonemic fluency, semantic fluency, category semantic fluency and reading fluency. This method uses verbal generation skills, activating different Broca's areas of the Brodmann's areas (BA44 …

Fail-Safe Testing Of Web Applications, Salah Boukhris

Electronic Theses and Dissertations

This dissertation introduces an approach to generate tests to test fail-safe behavior for web applications. We apply the approach to a commercial web application. We build models for both behavioral and mitigation requirements. We create mitigation tests from an existing functional black box test suite by determining failure type and points of failure in the test suite and weaving required mitigation based on weaving rules to generate a test suite that tests proper mitigation of failures. A genetic algorithm (GA) is used to determine points of failure and type of failure that needs to be tested. Mitigation test paths are …

Isolation In Synchronized Drone Formations, Andrew P. Brunner

Electronic Theses and Dissertations

This paper expands on a theoretical model that is used for aerial robots that are working cooperatively to complete a task. In certain situations, such as when multiple robots have catastrophic failures, the surviving robots could become isolated so that they never again communicate with another robot. We prove some properties about isolated robots flying in a grid formation, and we present an algorithm that determines how many robots need to fail to isolate at least one robot. Finally, we propose a strategy that eliminates the possibility of isolation altogether.

Particle Swarm Optimization Based Reactive Power Dispatch For Power Networks With Distributed Generation, Xiao Kou

Electronic Theses and Dissertations

Reactive power is critical to the operation of the power networks on both safety aspects and economic aspects. Unreasonable distribution of the reactive power would severely affect the power quality of the power networks and increases the transmission loss. Currently, the most economical and practical approach to minimizing the real power loss remains using reactive power dispatch method.

Reactive power dispatch problem is nonlinear and has both equality constraints and inequality constraints. In this thesis, PSO algorithm and MATPOWER 5.1 toolbox are applied to solve the reactive power dispatch problem. PSO is a global optimization technique that is equipped with …

Towards Closed-Loop Deep Brain Stimulation: Behavior Recognition From Human Stn, Soroush Niketeghad

Electronic Theses and Dissertations

Deep brain stimulation (DBS) provides significant therapeutic benefit for movement disorders such as Parkinson’s disease (PD). Current DBS devices lack real-time feedback (thus are open loop) and stimulation parameters are adjusted during scheduled visits with a clinician. A closed-loop DBS system may reduce power consumption and side effects by adjusting stimulation parameters based on patient’s behavior. Thus behavior detection is a major step in designing such systems. Various physiological signals can be used to recognize the behaviors. Subthalamic Nucleus (STN) Local field Potential (LFP) is a great candidate signal for the neural feedback, because it can be recorded from the …

Identification Of Geostationary Satellites Using Polarization Data From Unresolved Images, Andy Speicher

Electronic Theses and Dissertations

In order to protect critical military and commercial space assets, the United States Space Surveillance Network must have the ability to positively identify and characterize all space objects. Unfortunately, positive identification and characterization of space objects is a manual and labor intensive process today since even large telescopes cannot provide resolved images of most space objects. Since resolved images of geosynchronous satellites are not technically feasible with current technology, another method of distinguishing space objects was explored that exploits the polarization signature from unresolved images.

The objective of this study was to collect and analyze visible-spectrum polarization data from unresolved …

Finite Element Analysis Of Thermal Buckling In Automotive Clutch And Brake Discs, Huizhou Yang

Electronic Theses and Dissertations

Thermal buckling behavior of automotive clutch and brake discs is studied by making the use of finite element method. It is found that the temperature distribution along the radius and the thickness affects the critical buckling load considerably. The results indicate that a monotonic temperature profile leads to a coning mode with the highest temperature located at the inner radius. Whereas a temperature profile with the maximum temperature located in the middle leads to a dominant non-axisymmetric buckling mode, which results in a much higher buckling temperature. A periodic variation of temperature cannot lead to buckling. The temperature along the …

Thermomechanical Stabilities In Automotive Brakes & Clutches Systems, Ali Bendawi

Electronic Theses and Dissertations

This thesis involves three related topics in the area of thermal stress resulting from sliding contact of frictional materials. These three contributions collectively and the discussion of them herein form a collective basis furthering the research and understanding within this field. Firstly, the effect of convective cooling on thermoelastic instability is evaluated using finite element analysis involving insertion of a thermal convection term in the formula for frictional heat generation. It has been found that convection or radiation heat dissipation can stabilize the thermal-mechanical feedback process, leading to a raised critical sliding velocity. Two representative models for brake and clutch …

On Thermal Aging Prevention In Polymer Core Composite Conductor Rods, Joe D. Hoffman

Electronic Theses and Dissertations

Increased energy usage in the United States and worldwide is driving the demand for new technologies to transmit electrical power in greater quantities and with reliable, safe, and more efficient methods. One recent innovation is to replace the standard Aluminum Conductor Steel Reinforced electrical transmission conductor with a new conductor design that utilizes a fiber reinforced polymer core rod to support a fully annealed aluminum conductor. This new technology that includes a hybrid carbon fiber/epoxy and glass fiber/epoxy support core allows for better efficiency and for greater current to be transmitted in the same size and weight line. These new …

Locational Marginal Pricing At The Power Distribution Level, Jun Hao

Electronic Theses and Dissertations

During the development of smart grid at distribution level, the realization of real-time nodal pricing is one of the key challenges. This thesis proposes a novel methodology of locational marginal pricing at power distribution level. The nodal pricing mechanism is implemented utilizing both Direct Current Optimal Power Flow and Alternate Current Optimal Power Flow. The University of Denver campus power grid is used to develop the simulation test bed of the distribution level power system. In order to realize our approach, the first step is to extract the network topology from the DU campus grid utility map. The network topology …

Islanded Wind Energy Management System Based On Neural Networks, Ziqiao Liu

Electronic Theses and Dissertations

Wind power, as the main renewable energy source, is increasingly deployed and connected into electrical networks thanks to the development of wind energy conversion technologies. This dissertation is focusing on research related to wind power system include grid-connected/islanded wind power systems operation and control design, wind power quality, wind power prediction technologies, and its applications in microgrids. The doubly fed induction generator (DFIG) wind turbine is popular in the wind industry and thus has been researched in this Dissertation. In order to investigate reasons of harmonic generation in wind power systems, a DFIG wind turbine is modeled by using general …

Probabilistic Musculoskeletal Simulation Methods To Address Intersegmental Dependencies Of The Knee, Hip, And Spine, Casey A. Myers

Electronic Theses and Dissertations

Orthropaedic clinical practice in the area of the knee, hip, and spine has benefited from the concept of regional interdependence, where interventions applied to one region can influence the outcome and function of other regions of the body that may be seemingly unrelated to the applied intervention. An understanding of the biomechanical mechanisms that describe clinical practice involving knee, hip, and spine regional interdependence can improve treatment of a wide range of pathological conditions. Improvement in this area can be particularly impactful on the outcomes of patients with total joint replacement, where pathology and compensatory strategies develop during multi-joint interactions. …

Facial Expression Analysis Via Transfer Learning, Xiao Zhang

Electronic Theses and Dissertations

Automated analysis of facial expressions has remained an interesting and challenging research topic in the field of computer vision and pattern recognition due to vast applications such as human-machine interface design, social robotics, and developmental psychology. This dissertation focuses on developing and applying transfer learning algorithms - multiple kernel learning (MKL) and multi-task learning (MTL) - to resolve the problems of facial feature fusion and the exploitation of multiple facial action units (AUs) relations in designing robust facial expression recognition systems. MKL algorithms are employed to fuse multiple facial features with different kernel functions and tackle the domain adaption problem …

The Neuromuscular Response To Spinal Manipulation: Quantifying The Effect Of Pain With Electromyography, Stuart James Currie

Electronic Theses and Dissertations

Objective

To establish a methodology to quantify the neuromuscular response to spinal manipulation, develop a comprehensive date set including factors that affect the response, and compare the responses in both healthy participants and participants with acute and chronic low back pain.

Methods

Surface and indwelling electromyography at eight muscle locations were recorded during lumbar side-lying manipulations in 20 asymptomatic participants, 20 acute pain participants, and 20 chronic pain participants. Onset delay detection was optimized for signal detection failures and methodological comparisons were performed using a generalized linear model. The number of muscle responses and muscle activity onset delays in relation …