Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 25 of 25
Full-Text Articles in Entire DC Network
Acausal Modeling Of Wind Turbines With Validation And Control Studies, Kazi Ishtiak Mohsin
Acausal Modeling Of Wind Turbines With Validation And Control Studies, Kazi Ishtiak Mohsin
Graduate Thesis and Dissertation 2023-2024
This thesis involves the modeling, validation, and control studies of a Control-Oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), that is currently under development. CRAFTS uses Modelica®, an object-oriented, declarative, multi-domain modeling language for physical system modeling in the Dymola environment. The CRAFTS simulator facilitates rapid dynamic simulation of wind turbines with various model variants and enables control co-design.
A major emphasis of this thesis is in the validation of the CRAFTS simulator for a 15-MW land-based wind turbine through several test cases. These test cases were collaboratively developed in conjunction with other participating research entities. CRAFTS has undergone rigorous …
Workspace And Kinematic Modeling And Analysis Of Semi-Robotic Laparoscopic Surgery, Immanuel E. Girgis
Workspace And Kinematic Modeling And Analysis Of Semi-Robotic Laparoscopic Surgery, Immanuel E. Girgis
Honors Undergraduate Theses
Laparoscopic Surgery has been revolutionized by the world of Surgical Robotics. Robot-Assisted Surgeries have been proven to have many advantages over the fundamental, traditional "by-hand" procedures previously conducted, and still currently being done for certain operations. Robot-assisted surgery may offer benefits to patients through the use of minimally invasive techniques, which may result in reduced blood loss, reduced blood transfusion, fewer complications, reduced postoperative pain, shorter hospital stays, and reduced recovery times (Ho et al., 2011). Studies have proven that robotic surgery may lead to patients recovering faster depending on the timeframe and the type of procedure (Tang et al., …
Information Propagation Algorithms For Consensus Formation In Decentralized Multi-Agent Systems, Christopher Hollander
Information Propagation Algorithms For Consensus Formation In Decentralized Multi-Agent Systems, Christopher Hollander
Electronic Theses and Dissertations
Consensus occurs within a multi-agent system when every agent is in agreement about the value of some particular state. For example, the color of an LED, the position or magnitude of a vector, a rendezvous location, the most recent state of data within a database, or the identity of a leader are all states that agents might need to agree on in order to execute their tasking. The task of the decentralized consensus problem for multi-agent systems is to design an algorithm that enables agents to communicate and exchange information such that, in finite time, agents are able to form …
A Generic Framework For Multi-Method Modeling And Simulation Of Complex Systems Using Discrete Event, System Dynamics And Agent Based Approaches., Konstantinos Mykoniatis
A Generic Framework For Multi-Method Modeling And Simulation Of Complex Systems Using Discrete Event, System Dynamics And Agent Based Approaches., Konstantinos Mykoniatis
Electronic Theses and Dissertations
Decisions about Modeling and Simulation (M&S) of Complex Systems (CS) need to be evaluated prior to implementation. Discrete Event (DE), System Dynamics (SD), and Agent Based (AB) are three different M&S approaches widely applied to enhance decision-making of complex systems. However, single type M&S approaches can face serious challenges in representing the overall multidimensional nature of CS and may result in the design of oversimplified models excluding important factors. Conceptual frameworks are necessary to offer useful guidance for combining and/or integrating different M&S approaches. Although several hybrid M&S frameworks have been described and are currently deployed, there is limited guidance …
Assessing Biofiltration Pretreatment For Ultrafiltration Membrane Processes, Andrea Cumming
Assessing Biofiltration Pretreatment For Ultrafiltration Membrane Processes, Andrea Cumming
Electronic Theses and Dissertations
An engineered biological filtration (biofiltration) process treating a nutrient-enriched, low-alkalinity, organic-laden surface water downstream of conventional coagulation-clarification and upstream of an ultrafiltration (UF) membrane process was assessed for its treatment effectiveness. The impact of biofiltration pretreatment on UF membrane performance was evaluated holistically by investigating the native source water chemistry and extending the analysis into the drinking water distribution system. The biofiltration process was also compared in treatment performance to two alternative pretreatment technologies, including magnetic ion exchange (MIEX®) and granular activated carbon (GAC) adsorption. The MIEX®, GAC adsorption, and biologically active carbon (BAC) filtration pretreatments were integrated with conventional …
Design And Development Of Heterogenous Combustion Systems For Lean Burn Applications, Anthony Terracciano
Design And Development Of Heterogenous Combustion Systems For Lean Burn Applications, Anthony Terracciano
Electronic Theses and Dissertations
Combustion with a high surface area continuous solid immersed within the flame, referred to as combustion in porous media, is an innovative approach to combustion as the solid within the flame acts as an internal regenerator distributing heat from the combustion byproducts to the upstream reactants. By including the solid structure, radiative energy extraction becomes viable, while the solid enables a vast extension of flammability limits compared to conventional flames, while offering dramatically reduced emissions of NOx and CO, and dramatically increased burning velocities. Efforts documented within are used for the development of a streamlined set of design principles, and …
Modeling And Fault Detection In Dc Side Of Photovoltaic Arrays, Mohd Akram
Modeling And Fault Detection In Dc Side Of Photovoltaic Arrays, Mohd Akram
Electronic Theses and Dissertations
Fault detection in PV systems is a key factor in maintaining the integrity of any PV system. Faults in photovoltaic systems can cause irrevocable damages to the stability of the PV system and substantially decrease the power output generated from the array of PV modules. Among'st the various AC and DC faults in a PV system, the clearance of the AC side faults is achieved by conventional AC protection schemes,the DC side, however , there still exists certain faults which are difficult to detect and clear. This paper deals with the modeling, detection and classification of these types of DC …
Understanding The Capabilities And Limitations Of Advanced Interactive M&S: A Cricothyroidotomy Simulation Case Study, Lillian Campbell-Wynn
Understanding The Capabilities And Limitations Of Advanced Interactive M&S: A Cricothyroidotomy Simulation Case Study, Lillian Campbell-Wynn
Electronic Theses and Dissertations
Simulation for surgical education and training is increasingly perceived as a valuable contribution to traditional teaching methods providing a structured learning experience. Surgical simulations allow surgeons to practice tactics, techniques and procedures numerous times without the cost, limitations and ethical problems of using cadaver-based models. The goal of this research is to advance the use of modeling and simulation in support of emergency medical training. This research explores questions identified through a case study of two different modeling and simulation techniques – virtual reality and mannequins - in the support of combat emergency medical education and training. To reduce the …
Modeling And Simulation Of All-Electric Aircraft Power Generation And Actuation, David Woodburn
Modeling And Simulation Of All-Electric Aircraft Power Generation And Actuation, David Woodburn
Electronic Theses and Dissertations
Modern aircraft, military and commercial, rely extensively on hydraulic systems. However, there is great interest in the avionics community to replace hydraulic systems with electric systems. There are physical challenges to replacing hydraulic actuators with electromechanical actuators (EMAs), especially for flight control surface actuation. These include dynamic heat generation and power management. Simulation is seen as a powerful tool in making the transition to all-electric aircraft by predicting the dynamic heat generated and the power flow in the EMA. Chapter 2 of this dissertation describes the nonlinear, lumped-element, integrated modeling of a permanent magnet (PM) motor used in an EMA. …
Exploration Of The Impact Of Affective Variables On Human Performance In A Live Simulation, Ken Westerlund
Exploration Of The Impact Of Affective Variables On Human Performance In A Live Simulation, Ken Westerlund
Electronic Theses and Dissertations
Live simulations play an important role in allowing users to practice and develop skills they learn in training. Although live simulations are playing an increasingly important role in training, ways to improve them are not well understood or documented. In order to improve the efficacy of live simulation and maximize results from funds spent on training; this research examines the relationship between the affective variables of the participants and their performance in the live simulation. Prior to participating in the instructor development live simulation used in this study two training preference scales were administered to a group of trainees. These …
Surface Measurements And Predictions Of Full-Coverage Film Cooling, Gregory Natsui
Surface Measurements And Predictions Of Full-Coverage Film Cooling, Gregory Natsui
Electronic Theses and Dissertations
Full-coverage film cooling is investigated both experimentally and numerically. First, surface measurements local of adiabatic film cooling effectiveness and heat transfer augmentation for four different arrays are described. Reported next is a comparison between two very common turbulence models, Realizable k-ε and SST k-ω, and their ability to predict local film cooling effectiveness throughout a full-coverage array. The objective of the experimental study is the quantification of local heat transfer augmentation and adiabatic film cooling effectiveness for four surfaces cooled by large, both in hole count and in non-dimensional spacing, arrays of film cooling holes. The four arrays are of …
Unified Large And Small Signal State-Space Based Modeling And Symbolic Simulation For Pwm Converters, Ehab Shoubaki
Unified Large And Small Signal State-Space Based Modeling And Symbolic Simulation For Pwm Converters, Ehab Shoubaki
Electronic Theses and Dissertations
In this Dissertation, which concentrates on discrete modeling for control purposes of DC/DC converters and simulation through symbolic techniques. A Unified Discrete State-Space Model for power converters in CCM is presented. Two main approaches to arriving at the discrete model are used. The first approach involves an impulse function approximation of the duty cycle modulation of the converter switches, and this approach results in a small signal discrete model. The Second approach is direct and does not involve any approximation of the modulation, this approach yields both a large signal nonlinear discrete model and a linear small signal model. Harmonic …
Modeling Of Liquid Crystal Display And Photonic Devices, Zhibing Ge
Modeling Of Liquid Crystal Display And Photonic Devices, Zhibing Ge
Electronic Theses and Dissertations
Liquid crystal (LC) materials have been widely applied in electro-optical devices, among which display is the most successful playground and numerous new applications in photonic areas (such as laser beam steering devices) are also emerging. To well guide the device design for optimum performance, accurate modeling is of prior and practical importance. Generally, the modeling of LC devices includes two parts in sequence: accurate LC molecule deformation extraction under external electric fields and optical calculation thereafter for the corresponding electro-optical behaviors. In this dissertation, first, hybrid finite element method and finite difference method are developed to minimize the free energy …
An Investigation Of Size Exclusion And Diffusion Controlled Membrane Fouling, Colin Michael Hobbs
An Investigation Of Size Exclusion And Diffusion Controlled Membrane Fouling, Colin Michael Hobbs
Electronic Theses and Dissertations
The reduction of membrane productivity (i.e. membrane fouling) during operation occurs in virtually all membrane applications. Membrane fouling originates from the method by which membranes operate: contaminants are rejected by the membrane and retained on the feed side of the membrane while treated water passes through the membrane. The accumulation of these contaminants on the feed side of the membrane results in increased operating pressures, increased backwashing frequencies, increased chemical cleaning frequencies, and increased membrane replacement frequencies. The most significant practical implication of membrane fouling is increased operating and maintenance costs. As such, membrane fouling must be properly managed to …
Four Terminal Junction Field-Effect Transistor Model For Computer-Aided Design, Hao Ding
Four Terminal Junction Field-Effect Transistor Model For Computer-Aided Design, Hao Ding
Electronic Theses and Dissertations
A compact model for four-terminal (independent top and bottom gates) junction field-effect transistor (JFET) is presented in this dissertation. The model describes the steady-state characteristics with a unified equation for all bias conditions that provides a high degree of accuracy and continuity of conductance, which are important for predictive analog circuit simulations. It also includes capacitance and leakage equations. A special capacitance drop-off phenomenon at the pinch-off region is studies and modeled. The operations of the junction fieldeffect transistor (JFET) with an oxide top-gate and full oxide isolation are analyzed, and a semi-physical compact model is developed. The effects of …
Modeling The Influences Of Personality Preferences On The Selection Of Instructional Strategies Inintelligent Tutoring Systems, Robert Sottilare
Modeling The Influences Of Personality Preferences On The Selection Of Instructional Strategies Inintelligent Tutoring Systems, Robert Sottilare
Electronic Theses and Dissertations
This thesis hypothesizes that a method for selecting instructional strategies (specifically media) based in part on a relationship between learning style preference and personality preference provides more relevant and understandable feedback to students and thereby higher learning effectiveness. This research investigates whether personality preferences are valid predictors of learning style preferences. Since learning style preferences are a key consideration in instructional strategies and instructional strategies are a key consideration in learning effectiveness, this thesis contributes to a greater understanding of the relationship between personality preferences and effective learning in intelligent tutoring systems (ITS). This research attempts to contribute to the …
A Three-Dimensional Bay/Estuary Model To Simulate Water Quality Transport, Jing Yu
A Three-Dimensional Bay/Estuary Model To Simulate Water Quality Transport, Jing Yu
Electronic Theses and Dissertations
This thesis presents the development of a numerical water quality model using a general paradigm of reaction-based approaches. In a reaction-based approach, all conceptualized biogeochemical processes are transformed into a reaction network. Through the decomposition of species governing equations via Gauss-Jordan column reduction of the reaction network, (1) redundant fast reactions and irrelevant kinetic reactions are removed from the system, which alleviates the problem of unnecessary and erroneous formulation and parameterization of these reactions, and (2) fast reactions and slow reactions are decoupled, which enables robust numerical integrations. The system of species transport equations is transformed to reaction-extent transport equations, …
Study Of Nanoscale Cmos Device And Circuit Reliability, Chuanzhao Yu
Study Of Nanoscale Cmos Device And Circuit Reliability, Chuanzhao Yu
Electronic Theses and Dissertations
The development of semiconductor technology has led to the significant scaling of the transistor dimensions -The transistor gate length drops down to tens of nanometers and the gate oxide thickness to 1 nm. In the future several years, the deep submicron devices will dominate the semiconductor industry for the high transistor density and the corresponding performance enhancement. For these devices, the reliability issues are the first concern for the commercialization. The major reliability issues caused by voltage and/or temperature stress are gate oxide breakdown (BD), hot carrier effects (HCs), and negative bias temperature instability (NBTI). They become even more important …
A New Paradigm Of Modeling Watershed Water Quality, Fan Zhang
A New Paradigm Of Modeling Watershed Water Quality, Fan Zhang
Electronic Theses and Dissertations
Accurate models to reliably predict sediment and chemical transport in watershed water systems enhance the ability of environmental scientists, engineers and decision makers to analyze the impact of contamination problems and to evaluate the efficacy of alternative remediation techniques and management strategies prior to incurring expense in the field. This dissertation presents the conceptual and mathematical development of a general numerical model simulating (1) sediment and reactive chemical transport in river/stream networks of watershed systems; (2) sediment and reactive chemical transport in overland shallow water of watershed systems; and (3) reactive chemical transport in three-dimensional subsurface systems. Through the decomposition …
Modeling And Simulation Of Long Term Degradation And Lifetime Of Deep-Submicron Mos Device And Circuit, Zhi Cui
Electronic Theses and Dissertations
Long-term hot-carrier induced degradation of MOS devices has become more severe as the device size continues to scale down to submicron range. In our work, a simple yet effective method has been developed to provide the degradation laws with a better predictability. The method can be easily augmented into any of the existing degradation laws without requiring additional algorithm. With more accurate extrapolation method, we present a direct and accurate approach to modeling empirically the 0.18-ìm MOS reliability, which can predict the MOS lifetime as a function of drain voltage and channel length. With the further study on physical mechanism …
The Development Of A Fuzzy Model To Quantify Training Andeducational Factors And The Resulting Impact On Student Successand Lear, Chandre Butler
The Development Of A Fuzzy Model To Quantify Training Andeducational Factors And The Resulting Impact On Student Successand Lear, Chandre Butler
Electronic Theses and Dissertations
The utilization of fuzzy mathematical modeling for quantification of the quality of training and educational delivery is an innovative application that can result in measurable and repeatable results. This research was designed to apply proven quantification techniques and Industrial Engineering methodologies to a nontraditional environment. The outcomes of this research provide the foundation, initial steps and preliminary validation for the development of a systematic fuzzy theoretical model to be applied for the quantification of various areas within training and education delivery. The test bed for this methodology is Orange County Public School system, the twelfth largest school district in the …
An Automated Methodology For A Comprehensive Definition Of The Supply Chain Using Generic Ontological Components, Mohamed Fayez
An Automated Methodology For A Comprehensive Definition Of The Supply Chain Using Generic Ontological Components, Mohamed Fayez
Electronic Theses and Dissertations
Today, worldwide business communities are in the era of the Supply Chains. A Supply Chain is a collection of several independent enterprises that partner together to achieve specific goals. These enterprises may plan, source, produce, deliver, or transport materials to satisfy an immediate or projected market demand, and may provide the after sales support, warranty services, and returns. Each enterprise in the Supply Chain has roles and elements. The roles include supplier, customer, or carrier and the elements include functional units, processes, information, information resources, materials, objects, decisions, practices, and performance measures. Each enterprise, individually, manages these elements in addition …
Analysis And Integration Of A Debris Model In The Virtual Range Projec, Luis Robledo
Analysis And Integration Of A Debris Model In The Virtual Range Projec, Luis Robledo
Electronic Theses and Dissertations
After the accident of the STS 107 Columbia Space Shuttle, great concern has been focused on the risk associated to the population on the ground. Before this accident happened, re-entry routes as well as risk calculation of were not of public concern. Two issues that have been raised from this lamentable accident relate to spacecraft security and to public safety. The integration of a debris model has been part of the original conceptual architecture of the Virtual Range Project. Its integration has been considered as a specific research due to the complexity of the models and the difficulties to obtain …
Nitrification Investigation And Modeling In The Chloraminated Drinking Water Distribution System, Suibing Liu
Nitrification Investigation And Modeling In The Chloraminated Drinking Water Distribution System, Suibing Liu
Electronic Theses and Dissertations
This dissertation consists of five papers concerning nitrification in chloraminated drinking water distribution systems in a one and a half year field study. Seven finished waters were produced from different treatment processes and distributed to eighteen pilot distribution systems (PDSs) that were made pipes taken from actual distribution systems. Unlined cast iron (UCI), galvanized steel (G), lined cast iron (LCI), and PVC pipes were used to build the PDSs. All finished waters were stabilized and chloraminated before entering the PDSs. This dissertation consists of five major parts. (1) System variations of nitrates, nitrites, DO, pH, alkalinity, temperature, chloramine residuals and …
An Approach To Automating Data Collection For Simulation, Irin Portnaya
An Approach To Automating Data Collection For Simulation, Irin Portnaya
Electronic Theses and Dissertations
In past years many industries have utilized simulation as a means for decision making. That wave has introduced simulation as a powerful optimization and development tool in the manufacturing industry. Input data collection is a significant and complex event in the process of simulation. The simulation professionals have grown to accept it is as a strenuous but necessary task. Due to the nature of this task, data collection problems are numerous and vary depending on the situation. These problems may involve time consumption, lack of data, lack of structure, etc. This study concentrates on the challenges of input data collection …