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2013

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Articles 5071 - 5100 of 7290

Full-Text Articles in Engineering

Protoporphyrin Ix (Ppix)-Conjugated Self-Lighting Nanoparticles For Photodynamic Therapy: Synthesis And Characterization, Homa Homayoni Jan 2013

Protoporphyrin Ix (Ppix)-Conjugated Self-Lighting Nanoparticles For Photodynamic Therapy: Synthesis And Characterization, Homa Homayoni

Bioengineering Dissertations - Archive

In Photodynamic therapy (PDT) PDT, cancer destruction relies on applying a photosensitizing drug (PS) followed by light. Absorbed light can activate the PS to transfer energy to existing molecules and substrates or to oxygen to generate singlet oxygen which are highly toxic to cells. Protophorphyrin IX (PpIX) is a photosensitizers (PSs) which has FDA approval and an absorbance near the Soret band which is 10 times stronger than the absorbance in Q-band (600nm). Our goal was to design a modality to eliminate of external blue light in addition to increasing the drug's water dispersion which finally may result in enhancing …

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An Investigation Of Concurrent Variations In Blood Oxygen Saturation And Cerebral Blood Flow During Apnea, Jennifer Swittens Jan 2013

An Investigation Of Concurrent Variations In Blood Oxygen Saturation And Cerebral Blood Flow During Apnea, Jennifer Swittens

Bioengineering Theses - Archive

Sleep apnea derived from Greek word "apnoia" which means "without air or temporary interruption in breathing", is a sleep - associated breathing disorder that involves a decrease or complete stop in airflow despite a constant effort to breathe. It is estimated that sleep apnea is prevalent in the US in 18 million people and is approximately 6% of the population.This thesis aims to study the physiological effects of sleep apnea on cerebral blood flow (CBF) and the percentage oxygen saturation (%SaO2), the effect of duration of apnea episode or a breath hold on CBF and %SaO2 and to derive a …

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Establishment And Characterization Of An Animal Model Of Distraction Spinal Cord Injury, Jennifer Elisabeth Stearns Bell Jan 2013

Establishment And Characterization Of An Animal Model Of Distraction Spinal Cord Injury, Jennifer Elisabeth Stearns Bell

Bioengineering Dissertations - Archive

Scoliosis corrective surgery requires the application of multidirectional stress forces to the spinal cord, including those of distraction, in addition to the application of fixation rods for correction of the curved spine deformity. If excessive, spine distraction may result in the development of new neurologic deficits, some as severe as permanent paralysis. Intraoperative monitoring is used to alert the surgeon to possible complications; however, the complex nature of spinal cord injury (SCI) involves a primary mechanical insult to the tissue and/or vasculature that may go undetected by monitoring. This is followed by the activation of widespread secondary injury mechanisms. The …

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Diffuse Optical Tomography To Study The Ischemic Stroke In Rat Models, Zi-Jing Lin Jan 2013

Diffuse Optical Tomography To Study The Ischemic Stroke In Rat Models, Zi-Jing Lin

Bioengineering Dissertations - Archive

Stroke, including ischemic stroke and hemorrhagic stroke, is the major leading cause of death in the United States. More than 80 percent of stroke patients are diagnosed with ischemic stroke, which usually results from blockage of artery in the brain by thrombosis or arterial embolism. Animal Models, which permit powerful genetic and molecular approaches, provide an essential tool to study and understand the basic processes and potential therapeutic interventions for this disease. Significant efforts have been made to closely mimic the changes that occur in humans during and after stroke using animal models. Recent development on near infrared (NIR) diffuse …

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Development Of Statistical Models For Predicting Leachate Parameters From Simulated Landfills, Arpita Hetal Bhatt Jan 2013

Development Of Statistical Models For Predicting Leachate Parameters From Simulated Landfills, Arpita Hetal Bhatt

Civil Engineering Dissertations - Archive

Leachate generation and management is recognized as one of the greatest problems associated with environmentally sound operation of landfills, as leachate can cause major pollution problems to surrounding soil, ground water, and surface waters. There are many landfills, especially in developing parts of the world like India, Bangladesh, Africa, and Latin America, where open dump systems are used for final disposal of solid waste rather than engineered landfills. In the near future, regulations in developing countries will likely require installation of liner systems, leachate collection systems, and treatment operations. A major requirement for successful leachate treatment is quantifying its typical …

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Improving Analysis Of Heavy To Extreme Precipitation Using Conditional Bias-Penalized Optimal Estimation, Ridwan Siddique Jan 2013

Improving Analysis Of Heavy To Extreme Precipitation Using Conditional Bias-Penalized Optimal Estimation, Ridwan Siddique

Civil Engineering Theses - Archive

Precipitation estimation is a very important topic from the societal perspective as heavy precipitation can cause flooding from which loss of lives and damage to properties can occur. In current practice, a number of spatial interpolation techniques are used for precipitation estimation using rain gauge data. Most of them are based on minimizing error variance but none of them consider Type-II conditional bias. As such, the existing techniques work well in the mid ranges of the precipitation distribution but tend to under- and overestimate large and small precipitation amounts, respectively. Conditional bias- penalized kriging (CBPK) adds a penalty term for …

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The Pivotal Role Of Fibrocytes On Foreign Body Reactions, David William Baker Jan 2013

The Pivotal Role Of Fibrocytes On Foreign Body Reactions, David William Baker

Bioengineering Dissertations - Archive

Fibrocytes are circulating connective tissue precursor cells that were first described in 1994 by Bucala et al. as mediators of the innate immune response [1]. Recently the notion of a fibrocyte has not only gained widespread acceptance, but these cells have been identified to participate in a number of disease and pathologic states including aberrant wound repair, fibrosis of organs, cardiovascular disease, and even normal aging. Despite these advancements, little was known about the response of these dynamic cells to biomaterial implants and foreign body reactions. The main focus of my thesis work has therefore focused on investigating fibrocyte-mediate responses, …

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Staged Construction Modeling Of Large Diameter Steel Pipes Using 3-D Nonlinear Finite Element Analysis, Mojtaba Salehi Dezfooli Jan 2013

Staged Construction Modeling Of Large Diameter Steel Pipes Using 3-D Nonlinear Finite Element Analysis, Mojtaba Salehi Dezfooli

Civil Engineering Dissertations - Archive

This study investigates the performance of large diameter steel pipes during stage construction. Using this study, metal pipes are designed utilizing existing native soil for embedment around the pipe rather than imported materials. This indeed, translates into a considerable amount of cost saving and advances in designing pipeline. This model is used for peer review/ designing of a 242 km (150 miles) pipeline project, Integrated Pipeline (IPL), that transports approximately hundreds of millions of gallons from Lake Palestine, 137 km (85 miles) southeast of Dallas, to Lake Benbrook, Tarrant County, Texas. The IPL project supplies water to more than1.8 million …

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A Comparative Study Of Carbon Nanotubes And Granular Activated Carbon: Physicochemical Properties And Adsorption Capacities, Roja Haritha Gangupomu Jan 2013

A Comparative Study Of Carbon Nanotubes And Granular Activated Carbon: Physicochemical Properties And Adsorption Capacities, Roja Haritha Gangupomu

Civil Engineering Dissertations - Archive

Adsorption technologies with activated carbon have proven their prominence in wide variety of industrial applications for the removal of pollutants from gaseous streams for generations. Nanoadsorbents due to their unique structure and the presence of high-energy binding sites can enhance adsorption of pollutants, particularly for hazardous pollutants difficult to control using conventional sorbents like activated carbon and can help industries in their struggle for greener technologies. The objective of this study was to characterize raw and purified CNTs and compare their physical and chemical properties to commercially available granular activated carbon (GAC). The CNT purification process was done in two …

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Stabilization Of High Sulfate Soils, Nagasreenivasu Talluri Jan 2013

Stabilization Of High Sulfate Soils, Nagasreenivasu Talluri

Civil Engineering Dissertations - Archive

Stabilization of expansive soils using lime and cement has been a favorite technique for practitioners over the years. However, recent heaving and premature pavement failures in lime and cement treated subgrades containing sulfates led to question the validity of calcium based stabilization. When expansive soils containing sulfates are treated with calcium based stabilizers, calcium from stabilizer reacts with soil sulfate and clay alumina to form expansive mineral Ettringite. Formation and growth of the mineral Ettringite was reported as the cause of severe heaving in several pavement failures. Under favorable environmental conditions Ettringite transforms in to another expansive mineral Thaumasite. This …

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Development Of A Model For Estimation Of Buried Large Diameter Thin-Walled Steel Pipe Deflection Due To External Loads, Jwala Raj Sharma Jan 2013

Development Of A Model For Estimation Of Buried Large Diameter Thin-Walled Steel Pipe Deflection Due To External Loads, Jwala Raj Sharma

Civil Engineering Dissertations - Archive

Design of buried pipeline systems involves solution of geotechnical and structural problems in addition to the hydraulics and mechanical issues. Just like any buried structure, it is of utmost importance to understand how the pipe interacts with the soil when subjected to external and internal loads. Based on the mode of withstanding loads, pipes are classified into two major categories, which are rigid and flexible pipes. Pipe material is the major factor governing the classification of a pipe being rigid or flexible. Rigid pipe is a pipe which is designed to withstand external dead and live loads and internal pressure …

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Noninvasive Assessment Of Tumor Hypoxia Using Oxygen Sensitive Mri In Prostate Tumor Models, Rashmi Reddy Pabhathi Reddy Jan 2013

Noninvasive Assessment Of Tumor Hypoxia Using Oxygen Sensitive Mri In Prostate Tumor Models, Rashmi Reddy Pabhathi Reddy

Bioengineering Theses - Archive

A variety of solid tumors reveal oxygen deficiency as a result of rapid growth and insufficient tumor angiogenesis. Hypoxia in solid tumors appears to speed up malignant progression and metastatic potential of primary tumors thus leading to resistance against anticancer drugs and decreased response to radiotherapy.Of various in vivo non-invasive techniques to assess tumor hypoxia, oxygen-sensitive MRI (BOLD and TOLD) is an attractive and reliable option. Blood Oxygen Level Dependent (BOLD) and Tissue Oxygen Level Dependent (TOLD) MRI offer potential insight into tumor hypoxia. BOLD (Blood Oxygen Level Dependant) contrast MRI which measures R2* (1/T2*) is sensitive to endogenous paramagnetic …

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Assessment Of Stress/Volume-Controlled Soil-Water Retention Properties Of Unsaturated Sandy Soils., Hailu Ayalew Jan 2013

Assessment Of Stress/Volume-Controlled Soil-Water Retention Properties Of Unsaturated Sandy Soils., Hailu Ayalew

Civil Engineering Theses - Archive

The main objectives of this work are to determine the effect of net normal stress and volume change on the soil-water retention properties of silty sand and clayey sand soils under stressed/volume-controlled conditions; to model soil-water retention parameters under stress/volume-controlled conditions; and to model the effect of higher net normal stress state on the soil-water retention characteristics of these two test soils based on the experimental test results. In order to investigate the effect of stress/volume change on the soil-water retention characteristics of these two test soils, two test methods were followed: the stress/volume-controlled soil-water characteristic test (Tempe pressure cell …

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Development Of Non-Invasive Methods For Imaging Inflammatory Response, Yi-Ting Tsai Jan 2013

Development Of Non-Invasive Methods For Imaging Inflammatory Response, Yi-Ting Tsai

Bioengineering Dissertations - Archive

Persistent inflammatory cell reactions are responsible for the pathogenesis of a variety of inflammatory diseases. Although many non-invasive imaging methods have been used in the clinics to monitor the extent of inflammatory responses, almost all of them are based on indirect detection of inflammation-associated anatomical or structure changes of tissues and organs. To fill the gap, our laboratory has focused research efforts on detecting different processes of inflammatory responses. Our results can be summarized in the sequence of inflammatory responses - edema formation, inflammatory cell recruitment, inflammatory product release, and cell death. Shortly after medical device implantation or injury, edema …

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Kinetics Analyses Of Interactions Between Oncogenic And Tumor Suppressor Proteins By Quantitative High Resolution Microscopy Methods, Shu-Fen Tseng Jan 2013

Kinetics Analyses Of Interactions Between Oncogenic And Tumor Suppressor Proteins By Quantitative High Resolution Microscopy Methods, Shu-Fen Tseng

Bioengineering Dissertations - Archive

DAB2IP is correlated to the risk of aggressive prostate cancer and loss of DAB2IP not only leads to epithelial-to-mesenchymal transition (EMT), but also makes cells radioresistant. These observations support the notion that improved knowledge of DAB2IP involvement in cellular pathways could be of help to cancer therapy. The goal of this work was to enable the study of how DAB2IP and some of its known key molecular partners interact in the cell by a combination of molecular biology techniques and recently reported quantitative fluorescence microscopy methods. The first part of this work was dedicated on investigating the interaction of DAB2IP …

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Implementation Of Fast Residual Quadtree Coding And Fast Intra Prediction In High Efficiency Video Coding, Sapna Vasudevan Jan 2013

Implementation Of Fast Residual Quadtree Coding And Fast Intra Prediction In High Efficiency Video Coding, Sapna Vasudevan

Electrical Engineering Theses - Archive

High Efficiency Video Coding, one of the latest video compression schemes proposed by Joint Collaborative Team on Video Coding (JCT-VC) which is a partnership between International Telecommunication Union Video Coding Experts Group (ITU T-VCEG) and International Organization for Standardization Moving Picture Experts Group (ISO/IEC MPEG), has been promoted to Final Draft International Standard (FDIS) on January 25, 2013. With three profiles: main, main10 and still-frame, it achieves far better compression ratio than already existing schemes, while maintaining visual quality.However, this superior bitrate savings is achieved at the expense of huge computational complexity which in turn means higher encoding time. One …

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Investigation And Modeling Of Voltage And Current Unbalance On A Three-Phase Submersible Pump, James Andrew Reed Jan 2013

Investigation And Modeling Of Voltage And Current Unbalance On A Three-Phase Submersible Pump, James Andrew Reed

Electrical Engineering Theses - Archive

During the summer months of 2011, a North Texas subdivision experienced tripping difficulty with the submersible pump which is used to transfer water from an underground well to an above ground water storage tank. The tripping events were random in nature but occurred often. Under the suspicion that unbalanced phase voltages/currents are to blame, the local electrical cooperative sampled the line voltages/currents for several days in order to confirm the suspicions and better understand what the cause of the tripping events were. This thesis will discuss the analysis of that data and the development of a Simulink® based computer aided …

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Discriminant Processing In Multi-Class Pattern Recognition Systems, Soumitro Swapan Auddy Jan 2013

Discriminant Processing In Multi-Class Pattern Recognition Systems, Soumitro Swapan Auddy

Electrical Engineering Theses - Archive

Multi-Layer Perceptron neural network classifiers face problems when applications have numerous output classes. A major problem is the fact that the MLP discriminant values given by the MLP differ considerably from the posterior probabilities of the Bayes decision rule. A non-linear mapping technique is developed in this thesis, which warps the neural network outputs into posterior probabilities. A second problem is that when the neural network is given inputs for classes it is not trained to handle, the output discriminant values become very noisy, as compared to the values seen for correct inputs. Variance based methods are investigated for detecting …

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Implementation Of An Out-Of-The Loop Post-Processing Technique For Hevc Decoded Depth Maps, Parashar Nayana Karunakar Jan 2013

Implementation Of An Out-Of-The Loop Post-Processing Technique For Hevc Decoded Depth Maps, Parashar Nayana Karunakar

Electrical Engineering Theses - Archive

When depth-maps are compressed using the existing video codecs, the compression artifacts introduce distortions in the rendered views. To get better rendering, it is important to get rid of these compression artifacts. The thesis achieves this by using a post-processing frame-work on HEVC decoded depth maps. The proposed method is based on compression artifact analysis of depth maps. It implements a post-processing filter frame-work with an edge-adaptive joint trilateral filter [43] which can effectively minimize the effects of compression artifacts from the HEVC decoded depth-maps. The rendered views before and after applying the post-processing filter are compared with respect to …

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A Two Stage, Three Step Approach To Mobile Robot Path Planning And Control, John Robert Konderla Jan 2013

A Two Stage, Three Step Approach To Mobile Robot Path Planning And Control, John Robert Konderla

Electrical Engineering Theses - Archive

The potential field control model provides a powerful, yet mathematically simple method to motivate a mobile robot. It is a local control method based on simple physical principles. This allows the robot to proceed toward a target while avoiding obstacles following a naturally smooth path. It ensures the robot will behave according to Newtonian principles that have been studied for centuries. The potential field model has several weaknesses however. Most of the weaknesses can be lessened through careful modification of the potential field but the success of this approach is limited. For further improvements, global methods must be employed. These …

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Efficient Hevc Loss Less Coding Using Sample Based Angular Intra Prediction (Sap), Pavan Gajjala Jan 2013

Efficient Hevc Loss Less Coding Using Sample Based Angular Intra Prediction (Sap), Pavan Gajjala

Electrical Engineering Theses - Archive

High Efficiency Video Coding (HEVC) [3] is the next generation video compression standard being jointly developed by the Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T WP3/16 and ISO/IEC JTC 1/SC 29/WG 11. The loss less coding is prominent in real-time applications like automotive vision, video conferencing and in web collaboration for remote desktop sharing. HEVC with the lossless mode can help in these applications effectively by providing content with certain level of compression when compared to other lossless compression techniques. This thesis focuses on improving the compression efficiency for the lossless coding mode of HEVC by using a …

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Enhancement Of Security And Reliability With Mimo Communication For The Smart Grid, Amit Abhimanyu Deokar Jan 2013

Enhancement Of Security And Reliability With Mimo Communication For The Smart Grid, Amit Abhimanyu Deokar

Electrical Engineering Theses - Archive

In smart grid applications, developing appropriate wireless communication architecture is extremely important as wireless communication faces security and reliability challenges. To combat severe communication impairment induced by invader, it is proposed to implement space-time block coding over virtual MIMO. With an increment of diversity in virtual MIMO, BER performance has been improved by 18dB. Furthermore, with more redundant copies of transmitted signals at receiver, reliability of system has increased by 4 times in 4x1 V-MIMO and by 8 times in 8x1 V-MIMO than traditional SISO case. Security challenges from malicious additive attack and data piracy have been examined. Simulations show …

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Intra Frame Luma Mode Prediction Using Neural Networks In Hevc, Dilip Prasanna Kumar Jan 2013

Intra Frame Luma Mode Prediction Using Neural Networks In Hevc, Dilip Prasanna Kumar

Electrical Engineering Theses - Archive

High Efficiency Video Coding, the latest video coding standard proposed by the JVT-VC and three profiles- HEVC main, main 10 and main intraframe were adopted in January 2013, provides significant amount of compression compared to older standards, while retaining similar visual quality. This is achieved at the cost of a computationally expensive encoding method.Intra frame coding contributes to a large portion of the computational complexity. In this research, a way to speed up the intra frame prediction mode decision using Artificial Neural Networks is proposed. The search for the correct prediction mode is simplified by using neural networks to analyze …

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Modeling And Characterization Of The Insulated Gate Bipolar Transistor In The Near-Threshold Region, Farah P. Vandrevala Jan 2013

Modeling And Characterization Of The Insulated Gate Bipolar Transistor In The Near-Threshold Region, Farah P. Vandrevala

Electrical Engineering Theses - Archive

The Insulated Gate Bipolar Transistor (IGBT) is a power semiconductor device widely used in high-speed switching applications. Due to aging and internal heating, the device is prone to a failure mechanism known as latch-up in which, changes in the threshold voltage and the on-state voltage of the device may ultimately lead to loss of switching control.Since IGBTs are typically operated at high voltages and currents, the datasheets do not provide information on the static characteristics of the device for voltages close to the threshold, which is a useful region for understanding the underlying device physics.In this thesis a simplified IGBT …

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Complexity Reduction In Hevc Intra Coding And Comparison With H.264/Avc, Vinoothna Gajula Jan 2013

Complexity Reduction In Hevc Intra Coding And Comparison With H.264/Avc, Vinoothna Gajula

Electrical Engineering Theses - Archive

ITU-T (VCEG) and ISO/IEC (MPEG) collaborated and formed the joint collaborative team on video coding (JCT-VC) in April 2010 to develop the next-generation video coding (NGVC) standard.. HEVC standard doubles the coding efficiency and the approximately 50% less bit rate with respect to H.264/AVC, at nearly the same video quality at expense of increased complexity. In this thesis, a technique is proposed to reduce the complexity of HEVC intra coding to get better encoding time, involving two steps - first by optimizing the PU (prediction unit) size decision process using texture complexity analysis by intensity gradients and second to obtain …

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Physically Representative Atomistic Modeling Of Atomic-Scale Friction, Yalin Dong Jan 2013

Physically Representative Atomistic Modeling Of Atomic-Scale Friction, Yalin Dong

Mechanical Engineering Faculty Research

Nanotribology is a research field to study friction, adhesion, wear and lubrication occurred between two sliding interfaces at nano scale. This study is motivated by the demanding need of miniaturization mechanical components in Micro Electro Mechanical Systems (MEMS), improvement of durability in magnetic storage system, and other industrial applications. Overcoming tribological failure and finding ways to control friction at small scale have become keys to commercialize MEMS with sliding components as well as to stimulate the technological innovation associated with the development of MEMS. In addition to the industrial applications, such research is also scientifically fascinating because it opens a …

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Resilience Quantification And Its Application To A Residential Building Subject To Hurricane Winds, Berna E. Tokgoz, Adrian V. Gheorghe Jan 2013

Resilience Quantification And Its Application To A Residential Building Subject To Hurricane Winds, Berna E. Tokgoz, Adrian V. Gheorghe

Engineering Management & Systems Engineering Faculty Publications

In order to overcome negative consequences of a disaster, buildings and infrastructures need to be resilient. After a disaster occurs, they must get back to their normal operations as quickly as possible. Buildings and infrastructures should incorporate both pre-event (preparedness and mitigation) and post-event (response and recovery) resilience activities to minimize negative effects of a disaster. Quantitative approaches for measuring resilience for buildings and infrastructures need to be developed. A proposed methodology for quantification of resilience of a given building type based on different hurricane categories is presented. The formulation for the resilience quantification is based on a model embedding …

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Using Architecture Models To Design Adaptive Socio-Technical Systems, Holly A. H. Handley Jan 2013

Using Architecture Models To Design Adaptive Socio-Technical Systems, Holly A. H. Handley

Engineering Management & Systems Engineering Faculty Publications

An architecture framework is used to capture the overall design and structure of a complex system. The Human Viewpoint was developed to augment existing architectural frameworks with additional information relevant to the human component in the system. The Human View models collect and organize social parameters in order to understand the way that humans interact with other elements of the system; the Human View models define the socio-technological boundaries of the system. Analyses performed with the architectural data provide information regarding the congruence, or fit of the human and the system. For example, different key thread analyses identify problematic paths …

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Accounting For Errors When Using Systems Approaches, Kevin Macg. Adams, Peggy Hester Jan 2013

Accounting For Errors When Using Systems Approaches, Kevin Macg. Adams, Peggy Hester

Engineering Management & Systems Engineering Faculty Publications

Complex systems problems require the use of a formal philosophical construct and dictate the use of a rigorous systems approach. A systems approach may utilize one of a variety of proven methods, but in each case it involves the imposition of order that ranges from the philosophical to the procedural. Independent of the construct or rigor used to address the complex systems problem is the opportunity to commit a number of errors as part of a systems approach. This paper will discuss six classifications for problem solving errors that may be experienced during the application of a systems approach as …

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Impact Mechanics Of A Lap Joint: A Theoretical-Based Parametric Study, Seyed Amir Mansoor Rahmani Jan 2013

Impact Mechanics Of A Lap Joint: A Theoretical-Based Parametric Study, Seyed Amir Mansoor Rahmani

Electronic Theses and Dissertations

The failure of a single connection can cause overload on other structural members, which may consequently fail. Thus, the behavior of damaged or worn joints is of particular concern. In order to represent a loose lap joint, a beam impacting four springs with gaps is modeled. A basis analysis reveals impulse frequency responses with unique dynamic phenomena. Using steady state response, six influential parameters are studied: damping ratio, contact stiffness, position of intermediate springs, gaps, excitation amplitude and beam height. For all parameters, the system response was highly controlled by modes with two contacting springs. Regarding damping, increasing damping ratio …

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