Digital Commons Network^™

Multidisciplinary Modeling And Design Of A Space Structure, Brian K. Cassiday, Lawrence L. Gatchet, John T. Tester, Stephen O. Gaines Ii, Mario N. Moya

Theses and Dissertations

A method is needed to simultaneously integrate several engineering disciplines into one complete model to determine the performance of the system as a whole during the design development. System engineering methodologies are particularly suited to this problem. These methods provide a structured approach to problem formulation and system parameter identification. Bond graphs are also well suited as bond graphs model power flow and energy relationships within subsystems, a characteristic inherent to all dynamic systems. The intent of this research was to demonstrate the use of concurrent engineering theory to systematically model a large flexible space structure involving several engineering disciplines. …

Model-Based Reasoning In The Detection Of Satellite Anomalies, Ralph W. Dries

Theses and Dissertations

Automatic fault detection and recovery would be a mandatory requirement for a satellite where some degree of autonomy is required. This thesis reviews some AI techniques used for the detection of satellite anomalies, and concludes that the model-based reasoning paradigm is best suited for automated on-board fault detection because it can cope with situations not necessarily programmed into the knowledge base. Using the Scheme language and its SCOOPS object oriented extension, development of software is described that models the pitch control channel in the attitude and velocity control subsystem of a typical geo-stationary communications satellite. This model is used by …

Improving Reliability In A Stochastic Communication Network, William L. Gaught

Theses and Dissertations

This research investigated the behavior of increasing the reliability of components in stochastic communication networks. A stochastic communication network is one in which the components, links and nodes, are not 100 percent reliable. In addition the reliability value, each component also has a capacity value that limits the flow through the component. The throughput in a stochastic communication network can be improved by increasing the capacity or the reliability of the individual components. A set of linear and nonlinear models was developed to determine the best investment strategy for increasing the reliability of individual components. Once the models were developed, …

Proposed Design Of A Tactical Reconnaissance Satellite System, John D. T. Severance

Theses and Dissertations

Tactical reconnaissance is a much needed wartime asset, yet with the deactivation of all active-duty RF-4C squadrons world-wide there appears to be a gap in this country's war-fighting capability. This study proposes a system which utilizes a constellation of small tactical satellites and mobile ground receiving stations that can fulfill the tactical reconnaissance mission. A literature review gives background information on resolution variables, the RF-4C, space reconnaissance, and sensing technologies. After defining system requirements and constraints, a basic system concept is determined. Three alternative systems, separated mostly by threat scenario, technology, and cost, are evaluated using Athey's Systematic Systems Approach. …

Application Of Influence Diagrams In Identifying Soviet Satellite Missions, Cary C. Chun

Theses and Dissertations

This thesis investigates the feasibility of applying influence diagrams to capture expert knowledge and incorporate decision theory to construct a Soviet satellite mission prediction model. Before a Soviet launch occurs, formulations of the model's prior probability distribution allows the input of expert knowledge and any available information. As the predictive variables of the model become known, the information is used to successively refine the estimate of the probable mission, thereby, reducing the uncertainty in the model. Discretizing is used to approximate continuous variables as discrete variables which successfully allows the combination of both variable types in a single influence diagram …

Quantization Noise Characteristics Resulting From Gaussian, Negative- Exponential, And Sinusoidal Random Input Signals, Van N. Osborne

Theses and Dissertations

The purpose of this study was to investigate the trade-off between the number of quantization levels and the resulting noise characteristics for three classes of commonly occurring input signals, namely, those signals possessing Gaussian, negative-exponential and random sinusoidal distributions. This study derived expressions for the mean-squared error, output spectrum and error spectrum by expanding the nonlinear quantization function into a summation of orthogonal polynomials matched to the corresponding input signal distribution. Once accomplished, orthogonality properties were applied to provide usable expressions. A set of three Fortran 77 programs were developed- each of which applied to one of the studied input …

Digital Signal Processing Schemes For Fiber Optic Rotation Rate Sensor Scale Factor Linearization, David T. Dembinski

Masters Theses

This study examined and evaluated several scale factor linearization techniques for a fiber optic rotation rate sensor (FORS). The process of scale factor linearization retrieves rotation rate from an FORS signal. Open and closed loop digital signal processing schemes are evaluated on dynamic range, accuracy, and cost.

The results of these experiments show that open loop schemes require few components but have an inherently low dynamic range of operation. Extending the dynamic range of an open loop system is expensive in additional components. Closed loop systems require more initial components, but have a considerably superior dynamic range. It was concluded …

Radon Pressure Differential Project; Phase Ii Infiltration, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing has been done on 50 central Florida homes to assess and characterize house infiltration rates in new (age five years or less) Florida homes. These 50 were drawn randomly from a sample of 70 homes which had been previously tested to determine house airtightness, air distribution system leakage, and pressure differentials. The 50 homes had an average airtightness of 7.31 air changes per hour at 50 Pascals (ACH50). Significant leaks were found in the ductwork in a majority of homes tested, both on the supply and return sides of the air handler. When the air distribution system was sealed …

Radon Pressure Differential Project, Phase I, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Testing has been done on 70 central Florida homes to assess and characterize pressure differentials in new (age five years or less) Florida homes. Blower door testing was done to determine house airtightness and air distribution system leakage. The 70 homes had an average airtightness of 7.23 air changes per hour at 50 Pascals (ACH50). Significant leaks were found in the ductwork in a majority of homes tested, both on the supply and return sides of the air handler. When the air distribution system was sealed off, house ACH50 decreased to 6.42, indicating that 11.2% of the house leak area …

Waterways Transportation, Dick Cirre

Kentucky's Annual Forum on Transportation

No abstract provided.

General Session [1990], Eugene R. Mccormick

Kentucky's Annual Forum on Transportation

No abstract provided.

Segment Streaming For Efficient Pipelined Televisualization, Fengmin Gong

All Computer Science and Engineering Research

The importance of scientific visualization for both science and engineering endeavors has been well recognized. Televisualization becomes necessary because of the physical distribution of data, computation resources, and users involved in the visualization process. However, televisualization poses a number of challenges to the designers of communication protocols. A pipelined televisualization (PTV) model is proposed for efficient implementation of a class of visualization applications. Central to the proposed research is the development of a segment of streaming IPC (interprocess communication) mechanism in support of efficient pipelining across very high speed internetworks. This requires exploration of special issues arising from extending a …

Economic Development Through Advancing Transportation Technology, Charles L. Miller

Kentucky's Annual Forum on Transportation

No abstract provided.

Kentucky Transportation Hall Of Fame [1990], Kentucky Transportation Center

Kentucky's Annual Forum on Transportation

No abstract provided.

Acuta Enews November 1990, Vol. 19, No. 11

ACUTA Newsletters

In This Issue

Election of Directors

ICA backs universities

Vendor Liaison

An end to phone tag

Party Line

Hawaii air fares locked in

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, November 1990, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

A ten page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.

Numerical Analysis Of Critical Inclinations About The Planet Mars, Kenneth J. Hyatt

Theses and Dissertations

This study investigated critical inclinations about the planet Mars. Averaged equations of motion were numerically integrated over a time span of ten Earth years for various inclinations, eccentricities, and perigee heights. Each orbit (i.e. set of initial conditions) produced a standard deviation of the variations in eccentricity (SDE) and inclination (SDI). These were calculated using a polynomial approximation to the variations. Surface plots of SDI and SDE vs the initial conditions are then examined to ascertain the critical inclinations.

Minimum Orbits About The Planet Venus, Jeffrey J. Smith

Theses and Dissertations

An investigation is conducted into low orbiting satellites around the planet Venus with drag limited lifetimes. It is possible to specify combinations of orbital elements which result in orbital lifetimes in excess of some desired value. These combinations can be assembled into Critical Curves and Critical surfaces. Critical Curves and Surfaces are defined as curves and surfaces in orbital element space above which initial element sets will result in orbits that meet or exceed lifetime requirements. A numerical method is implemented for finding these combinations, and three Critical Surfaces are examined. A decay threshold is selected for bounding satellite lifetime. …

An Assessment Of Just-In-Time Manufacturing, Ronald E. O'Meara

Graduate Research Papers

Manufacturing of materials into useable products has changed dramatically since the Industrial Revolution. The United States dominated the manufacturing arena until the early 1970s. After that period, efforts of global competitors in such areas as quality control and productivity, started to surpass the efforts made by the United Stated in these same areas. For the first time, U.S. manufacturers started sensing the pressure of competition. The United Stated is using its competitive advantage over other nations in the manufacturing segment. Part of this loss is a result of the way the U.S. manufacturers are conducting their business. A larger part …

1990scholars And Artists Bibliography, Michael Schwartz Library, Cleveland State University, Friends Of The Michael Schwartz Library

Scholars and Artists Bibliographies

This bibliography was created for the annual Friends of the Michael Schwartz Library Scholars and Artists Reception, recognizing scholarly and creative achievements of Cleveland State University faculty, staff and emeriti

Safety Indexes For Shear-Bond Failure Of Composite Slabs, Laurence A. Mccuaig, R. M. Schuster

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Development And Verification Of A Structural System Using Cold-Formed Steel Wall Studs, T. Bond, E. R. Digirolamo, Teoman Pekoz

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

The Analysis Of Composite Slabs With Profiled Sheeting Using A Computer Based Semi-Empirical Partial Interaction Approach, Byron J. Daniels, David O'Leary, Michel Crisinel

CCFSS Proceedings of International Specialty Conference on Cold-Formed Steel Structures (1971 - 2018)

No abstract provided.

Acuta Enews October 1990, Vol. 19, No. 10

ACUTA Newsletters

In This Issue

Early warning of PVC fires

President's column

Attendant quiets complaints

Party Line

ISDN personalized

What do you charge?

The Calendar - October 1990, Nova University

The Calendar

No abstract provided.

Santa Clara Magazine, Volume 33 Number 1, Fall 1990, Santa Clara University

Santa Clara Magazine

12 - PRIESTS & MARRIAGE The Pope has allowed the ordination of nearly 50 married Episcopal priests since 1980. Some see this as a sign of hope for a married priesthood . By Julie Sly '82

18 - THE POWER OF ONE Because of her own personal tragedy, Mary Beth Cahill Phillips '76 forced the state of California to form Trustline, a registry parents can use to check out a nanny. By Susan Frey

20 - THE ART OF BIOGRAPHY Our natural curiosity about each other tempts us into reading biographies the same way we turn to novels. Is peering …

Integrated Control Of Thermally Distorted Large Space Antennas, Robert H. Tolson

Mechanical & Aerospace Engineering Theses & Dissertations

Studies on controlling the thermal distortion of large space antennae have generally investigated a single orbital position and have optimized actuator locations based on minimizing the RMS surface deviation from the original parabolic shape. One study showed the benefits of directly using far zone electric field characteristics as the performance measure; but, this approach resulted in a nonlinear programming problem. The objective of the current study is to develop an approach to designing a control system that (1) recognizes the time dependence of the distortion and (2) controls variables that are directly related to far field performance in a quadratic …

Space Structures: Issues In Dynamics And Control, H. Benaroya, Mark L. Nagurka

Mechanical Engineering Faculty Research and Publications

A selective technical overview is presented on the vibration and control of large space structures, the analysis, design, and construction of which will require major technical contributions from the civil/structural, mechanical, and extended engineering communities. The immediacy of the U.S. space station makes the particular emphasis placed on large space structures and their control appropriate. The space station is but one part of the space program, and includes the lunar base, which the space station is to service. This paper attempts to summarize some of the key technical issues and hence provide a starting point for further involvement. The first …

A Software Design Tool For Predictable Performance In Real-Time, Data Flow Architectures, Brij Mohan V. Mandala

Electrical & Computer Engineering Theses & Dissertations

A software design tool which aids in the performance evaluation and selection of operating points for an algorithm implemented in ATAMM defined data flow architectures is presented in this thesis. ATAMM (Algorithm To Architecture Mapping Model) is a new graph theoretic model developed by researchers at Old Dominion University and the NASA-Langley Research Center. ATAMM is capable of modeling the execution of large-grained algorithms on distributed data flow architectures. A software tool is required for predicting the performance, determining the resource requirements and for selecting suitable operating points for an ATAMM based system. The ATAMM Design Tool presented in this …

Deep Level Characterization Studies In Gaas, Gordhan R. Barevadia

Electrical & Computer Engineering Theses & Dissertations

The goal of this research was to investigate deep levels in different types of GaAs, a material for high power optically controlled bulk semiconductor switches. For low resistivity semiconductors, such as silicon doped GaAs material (p =0.054 Ω cm), deep level transient spectroscopy (DLTS) was used to characterize deep levels. Three deep levels (EL6, EL3, and EL2) have been detected in this material. For high resistivity semiconductors (p > 10⁴ Ω cm), difficulty of electrical carrier injection and of making a junction does not permit the use of DLTS technique. Therefore, an experimental set-up of the photo-induced current transient spectroscopy …