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Projects in 1988–1989

Aerospace Corporation: Construction of Data Base for Satellite Design

Michael Erlinger

The VEHICLES project is a two-fold effort in the construction of a database of knowledge related to the design of satellites. VEHICLES is a system for the conceptual design of satellites. The intent is to create a design aid with real knowledge of the practical as well as theoretical aspects of satellite design, consisting of several cooperating expert systems operating on a common database.

The VEHICLES system, even with the limited data so far entered, has proven a valuable tool in the solution of practical problems, while at the same time cutting new research ground in the design of expert systems. The first effort involved the team in the design of the database. They then proceeded to aid in the specification of the content and organization of an experimental database for use by the VEHICLES research project. This database was used by the VEHICLES system in performing trade studies and comparisons of new designs with systems which have already been designed.

General Dynamics: Modeling and Simulation of Neural Network Image Classifiers

Mario Martelli

Continuation of the '87-'88 project which examined the classification of ideal images. This year the efficiency of the algorithms developed were addressed, noise sensitivity was analyzed, and last year's results in rotational invariance were applied to the continuous transformations or groups of transformations. New results could make it possible to classify images after they have been distorted or scrambled.

Jet Propulsion Laboratory: Applications of Correlations Techniques

Janet Myhre

The JPL clinic project addressed the problem of scoring the degree of match between an observed signal and the known characteristics of various potential signal sources such as radios and radars. JPL was interested in studying the performance of both the standard scoring method and alternate methods. The clinic was responsible for the statistical analysis of the problem, the development of a computer simulation which captures the essential ingredients of the problem, and for analysis of simulation results.

NASA Dryden Flight Research Center: In-Flight Aeroelastic Stability Parameter Estimation

Courtney Coleman

The in-flight aeroelastic stability of aircraft is determined by estimating the damping of elastic structural modes of vibration. However, an algorithm has been developed to determine the aeroelastic stability without requiring the estimation of damping. The approach applied in this project was to further research and improve this new algorithm. The research consisted of incorporating a model for sensor noise, of incorporating a self adaptive algorithm, of providing the capability to analyze measured forced responses and programming the algorithm to run in real time. The end-item of this interchange was a written report and a computer program.

Northrop B2 Division: An Investigation of Reflection, Transmission and Absorption of Electromagnetic Energy

Robert Borrelli

The propagation, reflection and refraction of electromagnetic energy is easily computed for non-conducting and very conducting media. In order to solve electromagnetic problems encountered in aircraft design, the general case of arbitrary conductivity must be considered.

The first task of this team was to develop the equations for transmission, absorption and reflection for a plane electromagnetic wave incident upon a general “n-layered” medium. The team created algorithms for both isotropic and anisotropic materials. The team also researched optimization of the reflected wave and wave propagation in waveguides.

Teledyne Microelectronics: Establishment of a Basic Statistical Process Control Program

Daniel Hitt

This program should attempt to influence the output of some 5--10 manufacturing processes by establishing process control through statistical analysis. Included in this project could be a combination of statistical procedures involving Pareto Analysis, Standard Deviation, Cause and Effect Analysis, Process Capability Studies, and Test for Special Causes.

U.S. Forest Service: Statistical Analysis of Indices for the Evaluation of Forest Fire Potential

Gunnar Andersson

By using high altitude weather forecast information, some fire indices have been developed to optimize the allocation of fire fighting resources. These indices were analyzed to assess their reliability and probabilistic distribution. A computer program was developed to display this information in an easily usable graphic form.