Digital Commons Network^™

Resilience Of Backbone Provider Networks, Egemen K. Çetinkaya, Justin P. Rohrer, James P. G. Sterbenz

Electrical and Computer Engineering Faculty Research & Creative Works

Network topology models have drawn tremendous interest from the research community. Traditionally, Internet modelling has been done at the AS or router level, in part because this information is most available from tomography and public databases such as Rocketfuel. We argue that physical topology analysis is important for a more complete understanding of Internet structure, particularly for insight into the resilience and survivability of infrastructure against attacks and natural disasters. However, complexity and lack of complete data sets has hindered accurate topology modelling. In this short paper, we show through a sample case that physical topologies have significantly different characteristics …

Experimental Investigations Of Pseudospark Discharge And Pseudospark Produced Intense Electron Beams, Jing Hu

Doctoral Dissertations

"This dissertation focuses on the pseudospark discharge, a pulsed discharge discovered for the first time in 1970's. This dissertation is prepared as three journal articles in the style used by Missouri University of Science and Technology. A high voltage pseudospark discharge experiment setup, and discharge and electron beam diagnostic system are constructed and presented in this work. Three journal articles which have been published or are under review are presented in this dissertation on various topics of the pseudospark discharge.

Paper 1 "Experimental investigation of formation time in single-gap pseudospark discharge" is focused on experimental investigations of the time-dependent characteristics …

Analyzing Risk And Catastrophic Accidents: Using Lopa And Human Factors To Improve Safety In Generic Projects, Siddharth B. Damle

Doctoral Dissertations

"Risk assessment and identification in the early stages of any project is critical to the success of that project from time, budget and cost prespective [sic]. Identifying unacceptable risks and making provisions to mitigate those, can reduce the uncertainty in the project and ensure its smooth completion and closure. Various techniques have been developed over time to identify and quantify risks. Inspite of all the available research on risk management tools, accidents continue to happen and projects consistently fail.

The objective of this study is to first, determine the generic risks that can be encountered by a project. A list …

Transmission Scheduling Based On A New Conflict Graph Model For Multicast In Multihop Wireless Networks, Maggie Cheng, Quanmin Ye

Computer Science Faculty Research & Creative Works

In multicast applications, the end-to-end delay from the source to a group member is determined by the multicast tree topology and the waiting time at each relay node. This paper addresses when the multicast tree is given how to schedule wireless nodes for transmission so that network delay is minimized. We first model the conflict relation among wireless transmissions in a conflict graph, and then we compute a transmission schedule based on an Integer Linear Programming (ILP) model. Since solving ILP problem is NP-hard, a heuristic is designed to solve the ILP problem. the resulting schedule is conflict-free, which is …

Resilience Modelling Of Networks Against Adaptive Challenges, Egemen K. Çetinkaya, Justin P. Rohrer, James P. G. Sterbenz

Electrical and Computer Engineering Faculty Research & Creative Works

No abstract provided.

Approximate Policy Iteration For Markov Control Revisited, Abhijit Gosavi

Engineering Management and Systems Engineering Faculty Research & Creative Works

Q-Learning is based on value iteration and remains the most popular choice for solving Markov Decision Problems (MDPs) via reinforcement learning (RL), where the goal is to bypass the transition probabilities of the MDP. Approximate policy iteration (API) is another RL technique, not as widely used as Q-Learning, based on modified policy iteration. in this paper, we present and analyze an API algorithm for discounted reward based on (i) classical temporal differences update for policy evaluation and (ii) simulation-Based mean estimation for policy improvement. Further, we analyze for convergence API algorithms based on Q-factors for (i) discounted reward and (ii) …

Preface To Part Iii: Model Based Systems Engineering, Steven Corns

Engineering Management and Systems Engineering Faculty Research & Creative Works

No abstract provided.

Enabling Systems And The Adaptability Of Complex Systems-Of-Systems, Charles O. Adler, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

For complex techno-social system-of-systems, the system's robustness and its ability to adapt to changing environments and circumstances over the life cycle of the systems is an important measure of system quality and effectiveness. the IEEE 15288-2004 standard describes the concept of "enabling systems" that provide non-operational services to the system-of-interest at various times in the system life cycle. This concept of enabling systems provides critical components and perspective in the architecting and analysis of systems-of-systems adaptability and capabilities over time. Enabling systems also provide a potential strong link between the technical system and larger environmental effects such as economic conditions. …

Fuzzy Assessor Using Type 1 And Type 2 Fuzzy Sets, Paulette Acheson, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper provides a fuzzy assessor that can be used to evaluate system architectures. the fuzzy assessor includes a method of assigning system architecture attribute values to the lower-level subsystems using type 1 fuzzy sets and type 2 fuzzy sets. Each architecture attribute is evaluated at the lowest subsystem level and then mathematically rolled-up to provide the system level value for each architecture attribute. Then the value for each architecture attribute is combined into an overall system architecture performance value. This provides a mathematical method of qualitatively assessing a system architecture based on key architecture attributes. the fuzzy assessor uses …

Preface To Part Ii Computational Intelligence And Machine Learning, Rosemary D. Paradis, David Enke

Engineering Management and Systems Engineering Faculty Research & Creative Works

No abstract provided.

A New Hybrid Approach For Forecasting Interest Rates, David Enke, Nijat Mehdiyev

Engineering Management and Systems Engineering Faculty Research & Creative Works

The dynamic, non-linear, volatile and complex nature of interest rates makes it hard to predict their future movements. in order to deal with these complexities, the authors propose a two-stage neuro-hybrid forecasting model. in the initial data preprocessing stage, multiple regression analysis is implemented to determine the variables that have the strongest prediction ability. the selected variables are then provided as inputs to a Fuzzy Inference Neural Network to forecast future interest rate values. the proposed hybrid model is implemented using data from the U.S. interest rate market. © 2012 Published by Elsevier B.V.

Computational System Architecture Development Using A Holistic Modeling Approach, Renzhong Wang, Cihan H. Dagli

Engineering Management and Systems Engineering Faculty Research & Creative Works

This paper presents an innovative system architecture development framework that allows the search of optimum architecture solutions within large design space by automating certain model construction, alternative generation, simulation, and assessment tasks. Such framework is facilitated by a holistic modeling approach that combines the capabilities of Object Process Methodology (OPM), Colored Petri Net (CPN) and feature model. the resultant holistic model not only can capture the structural, behavior, and dynamic aspects of a system, allowing strong analysis methods to be applied, but also can specify the architectural design space allowing generation of architecture alternatives that cover it. the proposed framework …

Application Of Model-Based Systems Engineering On A University Satellite Design Team, Dustin Nottage, Steven Corns

Engineering Management and Systems Engineering Faculty Research & Creative Works

System Engineering is a foundation of the Missouri S&T's Satellite Design Team, although it is not explicitly stated at all times. However, implementation of the systems engineering process within a student design team presents unique challenges. Student design teams have a high personnel turnover, a limited time commitment due to classes, some new members have little to no experience, and a sometimes lack of motivation to participate since it is volunteered time. the largest problem on the team is getting the new members knowledgeable about the system so they can start contributing as fast as possible. the other big problem …

A Proposal To Use Real Time Pricing To Manage The Electrical Grid As A Step Toward Distributed Control, David Haynes, Steven Corns

Engineering Management and Systems Engineering Faculty Research & Creative Works

An alternative method of managing the electrical grid is presented. Rather than using a centralized control paradigm to balance generation against the load, a distributed approach is proposed. It is believed that this design improves the robustness of the grid by using an architecture that allows for the automatic formation of local micro grids. the self-organization of these micro-grids makes it possible to identify participants in an ad hoc fashion after a storm for purposes of disaster recovery. the micro-grid can automatically grow to encompass all participants and join with other grids to encompass the entire region. © 2012 Published …

Understanding System Of Systems Development Using An Agent-Based Wave Model, Paulette Acheson, Louis Pape, Cihan H. Dagli, Nil Kilicay-Ergin, John Columbi, Khaled Haris

Engineering Management and Systems Engineering Faculty Research & Creative Works

System of Systems (SoS) development is a complex process that depends on the cooperation of various independent Systems [1]. SoS acquisition and development differs from that typical for a single System; it has been shown to follow a wave paradigm known as the Wave Model [2]. Agent based models (ABMs) consist of a set of abstracted entities referred to as agents, and a framework using simplified rules for simulating agent decisions and interactions. Agents have their own goals and are capable of perceiving changes in the environment. Systemic (global) behavior emerges from the decisions and interactions of the agents. This …

A Fuzzy Inference Model For Predicting Irregular Human Behaviour During Stressful Missions, Sina Khanmohammadi, Cihan Hayreddin Dagli, Farnaz Zamani Esfahlani

Engineering Management and Systems Engineering Faculty Research & Creative Works

In this paper a hybrid fuzzy inference and transfer function modeling is used to predict the irregular human behavior during hard and stressful tasks such as dangerous military missions. a set of affecting factors such as missioner's experience, fatigue, sunshine intensity, hungriness, thirstiness, psychological characteristics, affright, etc. may be taken to account. in this regard a dynamic system model is used to predict the convolution of the timed effects of different factors on irregular behavior of personnel during the mission. This approach of predicting irregular behavior or erroneous decision making of staff have serious usages in aerospace, military, social and …

Meso-Scale Fluidic Devices With Chemical Sensors For Biological Applications, Satya Gowthami Achanta

Doctoral Dissertations

"Molecular oxygen and humidity are some of the major environmental quantities being measured for various industrial and commercial applications. This dissertation focuses on the design, fabrication and characterization of optofluidic biosensor systems for oxygen and humidity quantification using color charge-coupled device (CCD) camera as a photodetector and LED panel as an excitation source. Meso-scale fluidic devices with integrated oxygen and humidity sensors for potential applications to hydrotropic and oxytropic studies of small plant roots have been investigated in this study. Meso-scale sensor platform was fabricated using porphyrine complex as the sensitive dye embedded within Ethyl Cellulose (EC) polymer matrix. Green …

Role Of Alloy Additions On Strengthening In 17-4 Ph Stainless Steel, Arpana S. Murthy

Doctoral Dissertations

"Alloy modifications by addition of niobium (Nb ), vanadium (V), nitrogen (N) and cobalt (Co) to cast 17-4 PH steel were investigated to determine the effect on mechanical properties. Additions of Nb, V, and N increased the yield strength from 1120 MPa to 1310 MPa while decreased the room temperature charpy V notch (CVN) toughness from 20 J to four Joules. The addition of Co to cast 17-4 PH steel enhanced the yield strength and CVN toughness from 1140 MPa to 1290 MPa and from 3.7 J to 5.5 J, respectively. In the base 17-4 PH steel, an increase in …

Sieve Bootstrap Based Prediction Intervals And Unit Root Tests For Time Series, Maduka Rupasinghe

Doctoral Dissertations

"The application of the sieve bootstrap procedure, which resamples residuals obtained by fitting a finite autoregressvie (AR) approximation to empirical time series, to obtaining prediction intervals for integrated, long-memory, and seasonal time series as well as constructing a test for seasonal unit roots, is considered. The advantage of this resampling method is that it does not require knowledge about the underlying process generating a given time series and has been shown to work well for ARMA processes. We extend the application of the sieve bootstrap to ARIMA and FARIMA processes. The asymptotic properties of the sieve bootstrap prediction intervals for …

Stability Challenges And Solutions In Current-Mode Controlled Power Electronic Converters, Seyed Mostafa Khazraei

Doctoral Dissertations

"This dissertation focuses on stability issues in single-staged and multi-staged current controlled power electronic converters. Most current-mode control (CMC) approaches suffer from sub-harmonic oscillations. An external ramp is usually added to solve this problem. However, to guarantee stability this ramp has to be designed for the worst possible case which consequently over damps the response. Adaptive slope compensation (ASC) methods are the solution for this problem. In paper 1 of this dissertation, first three ASC methods will be investigated and analyzed through their small signal models. Then, through simulation analyses and experimental test of a variable-input voltage converter the results …

Shear And Fracture Behavior Of High-Volume Fly Ash Reinforced Concrete For Sustainable Construction, Carlos Andres Ortega Ordonez

Doctoral Dissertations

"Concrete is the most widely used man-made material on the planet. Unfortunately, producing Portland cement generates carbon dioxide (a greenhouse gas) at roughly a pound for pound ratio. High-volume fly ash (HVFA) concrete- concrete with at least 50% of the cement replaced with fly ash - offers a potential "green" solution. However, because it is still relatively new and has some disadvantages, there are still many questions that need to be answered. Most research to date has consisted only of the evaluation of the strength and durability of HVFA concrete mixtures, while only a limited number of studies have implemented …

Stochastic Optimal Adaptive Controller And Communication Protocol Design For Networked Control Systems, Hao Xu

Doctoral Dissertations

"Networked Control System (NCS) is a recent topic of research wherein the feedback control loops are closed through a real-time communication network. Many design challenges surface in such systems due to network imperfections such as random delays, packet losses, quantization effects and so on. Since existing control techniques are unsuitable for such systems, in this dissertation, a suite of novel stochastic optimal adaptive design methodologies is undertaken for both linear and nonlinear NCS in presence of uncertain system dynamics and unknown network imperfections such as network-induced delays and packet losses. The design is introduced in five papers.

In Paper 1, …

The Effects Of Personal Protective Respirators On Human Motor, Visual, And Cognitive Skills, Anas Ahmed Alghamri

Doctoral Dissertations

"In oxygen-deficient or toxic environments in which controlling the hazard is not feasible, workers wear personal protective respirators. Hazard controls include but are not limited to engineering controls, such as ventilation, and substituting less hazardous materials. However, respirator selection and the design of tasks that require respirators are critical issues. Understanding the effects of respirators on human abilities is critical to respirator selection and therefore to the safety and efficiency of workers. This research investigated the effect of respirators on human abilities. A review of the relevant literature was conducted, revealing that respirators can affect physiological, psychological, motor, and visual …

Investigation Of Biomarkers For Noninvasive Early Diagnosis Of Cancer, Sanjeewa Bandara Gamagedara

Doctoral Dissertations

"Cancer is the second leading cause of death worldwide, and deaths from cancer worldwide are projected to continue rising, with an estimated 12 million deaths in 2030. Cancer occurs when cells in a part of the body begin to grow out of control. It develops very rapidly, and early diagnosis offers a greater chance of successful treatment and a higher survival rate. Biomarkers are good potential tools for early diagnosis. The main hypothesis of this study is that the levels of certain metabolites present in human urine can indicate the current or future behavior of cancer. Therefore, these studies focused …

Hardware Emulation Of Wideband Correlated Multiple-Input Multiple-Output Fading Channels, Fei Ren, Yahong Rosa Zheng

Electrical and Computer Engineering Faculty Research & Creative Works

A low-complexity hardware emulator is proposed for wideband, correlated, multiple-input multiple-output (MIMO) fading channels. the proposed emulator generates multiple discrete-time channel impulse responses (CIR) at the symbol rate and incorporates three types of correlation functions of the subchannels via Kronecker product: The spatial correlation between transmit or receive elements, temporal correlation due to Doppler shifts, and inter-tap correlation due to multipaths. the Kronecker product is implemented by a novel mixed parallel-serial (mixed P-S) matrix multiplication method to reduce memory storage and to meet the real-time requirement in high data-rate, large MIMO size, or long CIR systems. We present two practical …

Optimization In Energy And Power Management For Renewable-Diesel Microgrids Using Dynamic Programming Algorithm, Tu A. Nguyen, Mariesa L. Crow

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents an optimization analysis for energy and power management in microgrids with renewable energy resources and diesel generators. Dynamic Programming (DP) algorithm and the simplex method have been used to minimize the total daily cost of the system and also maximize the total efficiency of the energy storage system during charge and discharge. the algorithm is validated on a hybrid system for military forward operating base camps that contain a PV array, wind generator, hydrogen-Based fuel cell, batteries and diesel generators. © 2012 IEEE.

A Self-Tuning Optimal Controller For Affine Nonlinear Continuous-Time Systems With Unknown Internal Dynamics, Travis Dierks, Sarangapani Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper presents a novel neural network (NN) - based self-tuning controller for the optimal regulation of affine nonlinear continuous-time systems. Knowledge of the internal system dynamics is not required whereas the control coefficient matrix is considered to be available. the proposed nonlinear optimal regulator tunes itself in order to simultaneously learn the optimal control input, optimal cost function, and the system internal dynamics using a single NN. a novel NN weight tuning algorithm is derived which ensures the internal system dynamics are learned while simultaneously minimizing a predefined cost function. an initial stabilizing controller is not required. Lyapunov methods …

Optimal Adaptive Controller Scheme For Uncertain Quantized Linear Discrete-Time System, Qiming Zhao, Hao Xu, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

In this paper, the Bellman equation is used to solve the optimal adaptive control of quantized linear discrete-time system with unknown dynamics. to mitigate the effect of the quantization errors, the dynamics of the quantization error bound and an update law for tuning the range of the dynamic quantizer are derived. Subsequently, by using adaptive dynamic programming technique, the infinite horizon optimal regulation problem of the uncertain quantized linear discrete-time system is solved in a forward-in-time manner without using value and/or policy iterations. the asymptotic stability of the closed-loop system is verified by standard Lyapunov stability approach in the presence …

State And Output Feedback-Based Adaptive Optimal Control Of Nonlinear Continuous-Time Systems In Strict Feedback Form, H. Zargarzadeh, T. Dierks, S. Jagannathan

Electrical and Computer Engineering Faculty Research & Creative Works

This paper focuses on neural network (NN) based adaptive optimal control of nonlinear continuous-time systems in strict feedback form with known dynamics. a single NN is utilized to learn the infinite horizon cost function which is the solution to the Hamilton-Jacobi-Bellman (HJB) equation in continuous-time. the corresponding optimal control input that minimizes the HJB equation is calculated in a forward-in-time manner without using value and policy iterations. First, the optimal control problem is solved in a generic multi-input and multi output (MIMO) nonlinear system in strict feedback form with a state feedback approach. Then, the approach is extended to single …

Promoting Search Diversity In Ant Colony Optimization With Stubborn Ants, Ashraf M. Abdelbar, Donald C. Wunsch

Electrical and Computer Engineering Faculty Research & Creative Works

In ant colony optimization (ACO) methods, including Ant System and MAX-MIN Ant System, each ant stochastically generates its candidate solution, in a given iteration, based on the same pheromone and heuristic information as every other ant. Stubborn ants is an ACO variation in which if an ant generates a particular candidate solution in a given iteration, then the components of that solution will have a higher probability of being selected in the candidate solution generated by that ant in the next iteration. In previous work, we evaluated this variation with the M M AS Ant System model and the Traveling …