Engineering Commons^™

Optimistic And Ability Biases In Pilots’ Decisions And Perceptions Of Risk Regarding Vfr Flight Into Imc, Dale R. Wilson, Marte Fallshore

All Faculty Scholarship for the College of Education and Professional Studies

Aircraft accidents resulting from attempted visual flight rules (VFR) flight into instrument meteorological conditions (IMC) continue to be one of the leading causes of fatalities in aviation. The aim of this study is to determine the role which two decision biases— optimistic bias and ability bias—may play in pilots’ decisions and perceptions of risk regarding VFR flight into IMC. A questionnaire designed to test for the presence of these biases was administered to 57 pilots enrolled in a university flight-training program and 103 general aviation pilots attending two FAA aviation safety seminars. Respondents were asked to rate their chances of …

Interval Computations As A Particular Case Of A General Scheme Involving Classes Of Probability Distributions, Scott Ferson, Lev Ginzburg, Vladik Kreinovich, Harry Schulte

Departmental Technical Reports (CS)

Traditionally, in science and engineering, measurement uncertainty is characterized by a probability distribution; however, we don't know this probability distribution exactly, so we must consider classes of probability distributions. Interval computations deal with a very specific type of such classes: classes of all distributions which are located on a given interval. We show that in general, we need all convex classes of probability distributions.

1st Order, 2nd Order, What Next? Do We Really Need Third-Order Descriptions: A View From A Realistic (Granular) Viewpoint, Vladik Kreinovich, Hung T. Nguyen

Departmental Technical Reports (CS)

To describe experts' uncertainty in a knowledge-based system, we usually use numbers from the interval [0,1] (subjective probabilities, degrees of certainty, etc.). The most direct way to get these numbers is to ask the expert; however, the expert may not be 100\% certain what exactly number describes his uncertainty; so, we end up with a second-order uncertainty - a degree of certainty describing to what extent a given number d adequately describes the expert's uncertainty about a given statement A. At first glance, it looks like we should not stop at this second order: the expert is probably as uncertain …

Examining Recent Expert Elicitation Judgment Guidelines: Value Assumptions And The Prospects For Rationality, Patricia Fleming

RISK: Health, Safety & Environment (1990-2002)

This paper was presented at the VALDOR Symposium, Stockholm, June 1999. The author examines the value assumptions in the U.S. Department of Energy and Nuclear Regulatory Commission guidance on the use of expert judgment relating to high level nuclear waste disposal site selection.

Computing The Shape Of The Image Of A Multi-Linear Mapping Is Possible But Computationally Intractable: Theorems, Raul A. Trejo, Vladik Kreinovich

Departmental Technical Reports (CS)

In systems without inertia (or with negligible inertia), a change in the values of control variables x1,...,xn leads to the immediate change in the state z of the system. In more precise terms, for such systems, every component zi of the state vector z=(z1,...,zd) is a function of the control variables. When we know what state z we want to achieve, the natural question is: can we achieve this state, i.e., are there values of the control variables which lead to this very state?

The simplest possible functional dependence is described by linear functions. For such functions, the question of …

An Even More Realistic (Non-Associative) Interval Logic And Its Relation To Psychology Of Human Reasoning, I. R. Goodman, Raul Trejo, Vladik Kreinovich, Jesus Martinez, Reginaldo Gonzalez

Departmental Technical Reports (CS)

No abstract provided.

On The Solution Of A Class Of Large Body Problems With Partial Circular Symmetry (Multiple Asymmetries) By Using A Hybrid-Dimensional Finite-Difference Time-Domain (Fdtd) Method, Dean Arakaki, Wenhua Yu, Raj Mittra

Electrical Engineering

This paper presents an efficient method to solve a large body scattering problem, viz. a paraboloid reflector antenna system, with only partial circular symmetry. The asymmetry in the system is introduced by two factors, viz. the microstrip feed and an inhomogeneous radome. The paper presents a novel approach, based on the equivalence and reciprocity principles and the “equivalent” aperture theory, to overcome the asymmetry problem. The technique thereby enables substantial computational efficiencies by analyzing the majority of the three-dimensional (3-D) computational domain in an effective two-dimensional (2-D) simulation, with the remainder being analyzed using a 3-D algorithm.

Flap Gate Design For Automatic Upstream Canal Water Level Control, Charles M. Burt, Russdon Angold, Mike Lehmkuhl, Stuart Styles

BioResource and Agricultural Engineering

The EXCEL design procedure for a simple hydraulic flap gate for automatic upstream canal water level control is provided. Basic configurations were developed in The Netherlands in the 1920s and have recently been used in Indonesia, the Dominican Republic, and Nigeria. Four irrigation districts in the San Joaquin Valley of California have constructed and installed over 60 properly functioning flap gates. The gates can be installed within 2 h, but require free discharge conditions and in practice are limited to controlling water depths of about 1 m or less.

Editor’S Note Advancement Of Phytoremediation, Joel Gerard Burken

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

No abstract provided.

Effects Of Supplemental Viscous Damping On Inelastic Seismic Response Of Asymmetric Systems, Rakesh K. Goel

Civil and Environmental Engineering

This paper investigates the effects of supplemental viscous damping on the seismic response of one‐storey, asymmetric‐plan systems responding in the inelastic range of behaviour. It was found that addition of the supplemental damping reduces not only deformation demand but also ductility and hysteretic energy dissipation demands on lateral load resisting elements during earthquake loading. However, the level of reduction strongly depends on the plan‐wise distribution of supplemental damping. Nearly optimal reduction in demands on the outermost flexible‐side element, an element generally considered to be the most critical element, was realized when damping was distributed unevenly in the system plan such …

Study Of Surface Chemical Changes And Erosion Rates For Cv-1144-O Silicone Under Electron Cyclotron Resonance Oxygen Plasma Exposure, Li Yan, Xiang Gao, Corey Bungay, John A. Woollam

Department of Electrical and Computer Engineering: Faculty Publications

CV-1144-O silicone thin films were irradiated in an electron cyclotron resonance oxygen plasma, which is a simulation of the low earth orbital environment. A crude equivalence between this plasma system and the low earth orbital environment was determined by measuring Kapton weight loss in the plasma and comparing to Kapton weight loss in space experiments. Changes in optical properties and erosion rates under ultraviolet light and atomic oxygen radiation were studied using in situ spectroscopic ellipsometry (SE). The erosion rate at the beginning of the plasma exposure was significantly faster than that at later stages. Approximately one third of the …

Why Unary And Binary Operations In Logic: General Result Motivated By Interval-Valued Logics, Hung T. Nguyen, Vladik Kreinovich, I. R. Goodman

Departmental Technical Reports (CS)

Traditionally, in logic, only unary and binary operations are used as basic ones - e.g., "not", "and", "or" - while the only ternary (and higher order) operations are the operations which come from a combination of unary and binary ones. For the classical logic, with the binary set of truth values {0,1}, the possibility to express an arbitrary operation in terms of unary and binary ones is well known: it follows, e.g., from the well known possibility to express an arbitrary operation in DNF form. A similar representation result for [0,1]-based logic was proven in our previous paper. In this …

How To Make Sure That "~100" + 1 Is ~100 In Fuzzy Arithmetic: Solution And Its (Inevitable) Drawbacks, Vladik Kreinovich, Hung T. Nguyen, Witold Pedrycz

Departmental Technical Reports (CS)

From the commonsense viewpoint, if a person who weighs around 100 kilograms gains one more kilogram, his weight is still around 100 kilograms. Alas, not so in traditional fuzzy arithmetic. In this paper, we propose a modification of fuzzy arithmetic which does have this property. We gain the desired property, but there is no free lunch, we have to lose two important properties of the traditional fuzzy arithmetic: first, addition is no longer always associative; second, addition is no longer always easily computable.

Modeling The Transient Rate Behavior Of Bandwidth Sharing As A Hybrid Control System, Kang Li, Molly H. Shor, Jonathan Walpole, Calton Pu

Computer Science Faculty Publications and Presentations

This paper uses hybrid control to model a problem of computer network systems, the dynamic behavior of bandwidth sharing among competing TCP traffic. It has been well known in the computer network community that well-behaved (TCP-friendly) congestion control mechanisms are crucial to the robustness of the Internet. Congestion control determines the transmission rate for each flow. Right now, most TCP-friendly research focuses only on the average throughput behavior without considering how the data is sent out in the short-term (e.g. bursty or smooth). However, recent experimental results show that short-term rate adjustments can change the bandwidth sharing result. Therefore, it …

Infosphere Project: An Overview, Calton Pu, Jonathan Walpole

Computer Science Faculty Publications and Presentations

We describe the Infosphere project, which is building the systems software support for information-driven applications such as digital libraries and electronic commerce. The main technical contribution is the Infopipe abstraction to support information flow with quality of service. Using building blocks such as program specialization, software feedback, domain-specific languages, and personalized information filtering, the Infopipe software generates code and manage resources to provide the specified quality of service with support for composition and restructuring.

Testing Of Bolted Cold-Formed Steel Connections In Bearing (With And Without Washers), J. A. Wallace, R. M. Schuster, Roger A. Laboube

American Iron and Steel Institute (AISI) Specifications, Standards, Manuals and Research Reports (1946 - present)

No abstract provided.

Acuta Enews March 2001, Vol.30, No. 3

ACUTA Newsletters

ACUTA Resource Library Is Growing

Spotlight on Volunteers

DC Update

Kent State Wins Network World Award

Overheard on the Listserve: Who Owns the Cable?

High Tech Short Takes

Welcome New Members

Positions Available

In Vivo Flow Dynamics Of The Total Cavopulmonary Connection From Three-Dimensional Multislice Magnetic Resonance Imaging, Shiva Sharma, Ann E. Ensley, Katherine Hopkins, George P. Chatzimavroudis, Timothy M. Healy, Vincent K.H. Tam, Kirk R. Kanter, Ajit P. Yoganathan

Chemical & Biomedical Engineering Faculty Publications

Background. The total cavopulmonary connection (TCPC) design continues to be refined on the basis of flow analysis at the connection site. These refinements are of importance for myocardial energy conservation in the univentricular supported circulation. In vivo magnetic resonance phase contrast imaging provides semiquantitative flow visualization information. The purpose of this study was to understand the in vivo TCPC flow characteristics obtained by magnetic resonance phase contrast imaging and compare the results with our previous in vitro TCPC flow experiments in an effort to further refine TCPC surgical design.

Methods. Twelve patients with TCPC underwent sedated three-dimensional, multislice …

Flight Physician - March, 2001, Civil Aviation Medical Association

Browse all Civil Aviation Medical Association Newsletters

A seventeen page newsletter of the Civil Aviation Medical Association. The newsletter provided news about civil aviation medicine and information related to the organization.

Network Formalism For Modeling Functionally Gradient Piezoelectric Plates And Stacks And Simulations Of Rainbow Ceramic Actuators, Robert W. Schwartz, A. Ballato, John Ballato

Mechanical and Aerospace Engineering Faculty Research & Creative Works

A simple network representation is given for a stack of thin, homogeneous piezoelectric plates, executing a single thickness mode of motion. All plates may differ in thickness and material properties, including dielectric loss, ohmic conductivity, and viscous loss. Each plate is driven by a thickness-directed electric field, and all stack elements are connected electrically in series. Functionally gradient single plates and composites are readily modeled by the network, to a desired precision, using a sequence of circuit elements representing stepwise variations in material properties and layer thicknesses. Simulations of RAINBOW (reduced and internally biased oxide wafer) ceramics are given.

Influence Of Feedback And Comment Labels On Information Sharing In A Computer Mediated Collaborative Environment, Gary D. Denney

Theses and Dissertations

A group support system (GSS) uses a combination of networked personal computers, software, and human facilitation to improve the group decision-making process. Group support Systems are being used in the Air Force today in a variety of capacities and in particular by the Warner-Robins Air Logistics Center (WR-ALC) to assess acquisition risks. Prior GSS research has found that certain structural and social dimensions of GSS designs might influence whether optimal process improvements take place. However, the dimensions that positively influence group performance have continued to be a matter of debate. This thesis looked at several structural and social contingencies to …

Turbine Blade Surface Roughness Effects On Shear Drag And Heat Transfer, Jess W. Drab

Theses and Dissertations

This work used scaled samples of actual turbine blade surfaces to characterize correlations between turbine surface roughness, friction coefficient, and convective heat transfer rate-parameters which affect an engine's efficiency and the blade's lifespan. For erosion/deposits, friction coefficients up to 250 times higher and convective heat transfer coefficients of up to 150 times higher were found when compared to a flat plate baseline. Other roughness types (pitting and fuel deposits) yielded less dramatic results. These results did not follow existing friction coefficient-to-heat transfer coefficient correlations, such as the Reynolds analogy. While these analytical and empirical correlations hold for flat plates, they …

Multiple Model Adaptive Estimation For Time Series Analysis, Ibrahim Dulger

Theses and Dissertations

Multiple Model Adaptive Estimation (MMAE) is a Bayesian technique that applies a bank of Kalman filters to predict future observations. Each Kalman filter is based on a different set of parameters and hence produces different residuals. The likelihood of each Kalman filter's prediction is determined by a magnitude of the residuals. Since some researchers have obtained good forecasts using a single Kalman filter, we tested MMAE's ability to make time series predictions. Our Kalman filters have a dynamics model based on a Box-Jenkins Auto-Regressive Moving Average (ARMA) model and a measure model with additive noise. The time-series prediction is based …

The Effect Of External Safeguards On Human-Information System Trust In An Information Warfare Environment, Gregory S. Fields

Theses and Dissertations

This research looks at how human trust in an information system is influenced by external safeguards in an Information Warfare (1W) domain. Information systems are relied upon in command and control environments to provide fast and reliable information to the decision-makers. The degree of reliance placed in these systems by the decision-makers suggests a significant level of trust. Understanding this trust relationship and what effects it is the focus of this study. A model is proposed that predicts behavior associated with human trust in information systems. It is hypothesized that a decision-maker's belief in the effectiveness of external safeguards will …

Quality Initiatives In The Air Force Development Of Reusable Launch Vehicles, Charles S. Galbreath

Theses and Dissertations

This thesis identifies useful tools and techniques available to aid the Air Force development of a reusable launch vehicle (RLV). These tools are identified by comparing traits found within the Lean Aerospace Initiative, Six Sigma and systems engineering. While identified specifically for the RLV effort, these tools and techniques will be of use to many development programs. Historical perspectives of both RLV development efforts within the Air Force and origins of modern quality teachings are provided to establish a common foundation of knowledge, upon which, further analysis can be conducted. This thesis, also, summarizes the current RLV effort within the …

Evaluation Of Strategy-Structure Fit Of Space And Missile Systems Center Detachment 11, Tommy M. Gates

Theses and Dissertations

Activated June 1,1998, Space and Missile Systems Center Detachment 11, located in Colorado Springs, integrates system support management for the Satellite Launch Control System (SLCS), MlLSTAR, the Defense Meteorological Support Program (DMSP), the Space Based Infrared System (SBlRSl, and the Global Positioning System (GPS). The Detachment performs operational software maintenance, satellite systems engineering, space testing and evaluation, and technology master planning. Contemporary management theory asserts that the appropriate match of strategy and structure determines an organization's level of performance. The Detachment is currently organized programmatically. The current programmatic organizational structure represents the physical manifestation of the Integrated Weapon System Management …

Prediction Of Pilot Induced Oscillations (Pio) Due To Activator Rate Limiting Using The Open-Loop Onset Point (Olop) Criterion, Gregory P. Gilbreath

Theses and Dissertations

Rate limiting has been a causal or contributing factor for Pilot Induced Oscillations (PIO). As part of the joint Air Force Institute of Technology/Test Pilot School (AFIT/TPS) program, an examination of the Open-Loop Onset Point (OLOP) criterion, developed by DLR German Aerospace, was conducted to see if it could predict PIO due to rate limiting and to evaluate its potential as a design tool. The criterion was applied to three previous flight test programs involving rate limiting. Findings from this analysis led to the HAVE OLOP flight test which was flown on the NF-16D Variable Stability In-flight Simulator Test Aircraft …

An Objective Evaluation Of Four Sar Image Segmentation Algorithms, Jason B. Gregga

Theses and Dissertations

Because of the large number of SAR images the Air Force generates and the dwindling number of available human analysts, automated methods must be developed. A key step towards automated SAR image analysis is image segmentation. There are many segmentation algorithms, but they have not been tested on a common set of images, and there are no standard test methods. This thesis evaluates four SAR image segmentation algorithms by running them on a common set of data and objectively comparing them to each other and to human segmentors. This objective comparison uses a multi-metric a approach with a set of …

Cooperative Behavior Schemes For Improving The Effectiveness Of Autonomous Wide Area Search Munitions, Daniel P. Gillen

Theses and Dissertations

The problem being addressed is how to best find and engage an unknown number of targets in unknown locations using multiple autonomous wide area search munitions. In this research cooperative behavior is being investigated to improve the overall mission effectiveness. A simulation was used to emulate the behavior of autonomous wide area search munitions and measure their overall expected performance. This code was modified to incorporate the capability for cooperative engagement based on a parameterized decision rule. Using Design of Experiments and Response Surface Methodologies, the simulation was run to achieve optimal decision rule parameters for given scenarios and to …

Control And Characterization Of Line-Addressable Micromirror Arrays, Harris J. Hall

Theses and Dissertations

This research involved the design and implementation of a complete line-addressable control system for a 32x32 electrostatic piston-actuated micromirror array device. Line addressing reduces the number of control lines from N² to 2N making it possible to design larger arrays and arrays with smaller element sizes. The system utilizes the electromechanical bi-stability of individual elements to bold arbitrary bi-stable phase patterns. The control system applies pulse width modulated (PWM) signals to the rows and columns of the micromirror array. Three modes of operation were conceived and built into the system. The first was the traditional signal scheme which requires …