The 1990 Goddard Conference on Space Applications of Artificial Intelligence

The papers presented at the 1990 Goddard Conference on Space Applications of Artificial Intelligence are given. The purpose of this annual conference is to provide a forum in which current research and development directed at space applications of artificial intelligence can be presented and discussed. The proceedings fall into the following areas: Planning and Scheduling, Fault Monitoring/Diagnosis, Image Processing and Machine Vision, Robotics/Intelligent Control, Development Methodologies, Information Management, and Knowledge Acquisition

Research report: 1983-1985

The Environmental Quality Laboratory at Caltech is a center for research on large scale systems problems of natural resources and environmental quality. The principal areas of investigation at EQL are: 1. Air quality management. 2. Water resources and water quality management. 3. Control of hazardous substances in the environment. 4. Energy policy, including regulation, conservation and energy-environment trade-offs. 5. Resources policy (other than energy); residuals management. EQL research includes technical assessments, computer modeling, studies of environmental control options, policy analyses, and research on important components of the large scale systems. Field work is also undertaken at EQL, some in collaboration with other organizations, to provide critical data needed for evaluation of systems concepts and models. EQL's objectives are as follows: 1. To do systematic studies of environmental and resources problems. The results of these studies, including the clarification of policy alternatives. are communicated to decision-makers in government and industry, to the research community, and to the public. As an organization. EQL refrains from advocating particular policies, but seeks to point out the implications of the various policy alternatives. 2. To contribute to the education and training of people in these areas through involvement of pre-doctoral students, post-doctoral fellows, and visiting faculty members in EQL activities. This educational effort is just as important as the results of the studies themselves, and should make lasting contributions to the nation's ability to solve its environmental and resources problems. The work at EQL goes beyond the usual academic research in that it tries to organize and develop the knowledge necessary to clarify society's alternatives by integrating relevant disciplines. EQL works on solving problems of specific localities when there is a strong element of public interest or educational value, or the concepts and results are applicable to other places. The research of EQL is done under the supervision of faculty members in Environmental Engineering Science, Chemical Engineering, and Social Science. This research report covers the period from October 1983 through September 1985

Federal Register

Daily publication of the U.S. Office of the Federal Register contains rules and regulations, proposed legislation and rule changes, and other notices, including "Presidential proclamations and Executive Orders, Federal agency documents having general applicability and legal effect, documents required to be published by act of Congress, and other Federal agency documents of public interest" (p. ii). Table of Contents starts on page iii

A RISK-INFORMED DECISION-MAKING METHODOLOGY TO IMPROVE LIQUID ROCKET ENGINE PROGRAM TRADEOFFS

This work provides a risk-informed decision-making methodology to improve liquid rocket engine program tradeoffs with the conflicting areas of concern affordability, reliability, and initial operational capability (IOC) by taking into account psychological and economic theories in combination with reliability engineering. Technical program risks are associated with the number of predicted failures of the test-analyze-and-fix (TAAF) cycle that is based on the maturity of the engine components. Financial and schedule program risks are associated with the epistemic uncertainty of the models that determine the measures of effectiveness in the three areas of concern. The affordability and IOC models' inputs reflect non-technical and technical factors such as team experience, design scope, technology readiness level, and manufacturing readiness level. The reliability model introduces the Reliability- As-an-Independent-Variable (RAIV) strategy that aggregates fictitious or actual hotfire tests of testing profiles that differ from the actual mission profile to estimate the system reliability. The main RAIV strategy inputs are the physical or functional architecture of the system, the principal test plan strategy, a stated reliability-bycredibility requirement, and the failure mechanisms that define the reliable life of the system components. The results of the RAIV strategy, which are the number of hardware sets and number of hot-fire tests, are used as inputs to the affordability and the IOC models. Satisficing within each tradeoff is attained by maximizing the weighted sum of the normalized areas of concern subject to constraints that are based on the decision-maker's targets and uncertainty about the affordability, reliability, and IOC using genetic algorithms. In the planning stage of an engine program, the decision variables of the genetic algorithm correspond to fictitious hot-fire tests that include TAAF cycle failures. In the program execution stage, the RAIV strategy is used as reliability growth planning, tracking, and projection model. The main contributions of this work are the development of a comprehensible and consistent risk-informed tradeoff framework, the RAIV strategy that links affordability and reliability, a strategy to define an industry or government standard or guideline for liquid rocket engine hot-fire test plans, and an alternative to the U.S. Crow/AMSAA reliability growth model applying the RAIV strategy

Formal verification of AI software

The application of formal verification techniques to Artificial Intelligence (AI) software, particularly expert systems, is investigated. Constraint satisfaction and model inversion are identified as two formal specification paradigms for different classes of expert systems. A formal definition of consistency is developed, and the notion of approximate semantics is introduced. Examples are given of how these ideas can be applied in both declarative and imperative forms

Siting nuclear power plants in California: the near-term alternatives

There are many issues presently being debated concerning the generation and utilization of electric power in California. Some are peculiar to a specific area, such as the level of air quality and how it is influenced by fossil-fuel power plants. Others are of general applicability, such as high-level waste disposal from nuclear reactors, which is of global concern. It is the purpose of this study to investigate one particular aspect of the power problem. This is the question of the relative desirability of locating nuclear power plants at sites along the California coastline or at inland locations. In this introductory section, the basic problem will be outlined, including expected growth in electrical usage, and the nature of the controversy, which lies in the allocation of limited resources. In subsequent sections, the environmental impacts of coastal and inland plant siting will be discussed in general, without reference to specific locations. Conflicting demands for limited resources (namely, the coastline area and cooling water supply) will also be explored and evaluated. Finally, with the aid of this generalized information, a comparison will be made of the siting alternatives

Working Notes from the 1992 AAAI Spring Symposium on Practical Approaches to Scheduling and Planning

The symposium presented issues involved in the development of scheduling systems that can deal with resource and time limitations. To qualify, a system must be implemented and tested to some degree on non-trivial problems (ideally, on real-world problems). However, a system need not be fully deployed to qualify. Systems that schedule actions in terms of metric time constraints typically represent and reason about an external numeric clock or calendar and can be contrasted with those systems that represent time purely symbolically. The following topics are discussed: integrating planning and scheduling; integrating symbolic goals and numerical utilities; managing uncertainty; incremental rescheduling; managing limited computation time; anytime scheduling and planning algorithms, systems; dependency analysis and schedule reuse; management of schedule and plan execution; and incorporation of discrete event techniques

A study of systems implementation languages for the POCCNET system

The results are presented of a study of systems implementation languages for the Payload Operations Control Center Network (POCCNET). Criteria are developed for evaluating the languages, and fifteen existing languages are evaluated on the basis of these criteria

Assessment of emergency core cooling system effectiveness for light water nuclear power reactors

The effectiveness of Emergency Core Cooling Systems (ECCS) for light water nuclear power reactors was the subject of lengthy, controversial and technically complex hearings conducted by the AEC over the two years from 1971 through 1973. An independent, objective review and assessment of the technical issues associated with ECCS effectiveness was conducted in a study performed at the Environmental Quality Laboratory of the California Institute of Technology. The review was based upon the testimonies and supporting technical documentation of the principal participants in the hearings: the AEC, utilities, reactor manufacturers, and intervenors. From the review, the critical technical parameters influencing ECCS performance, which were at issue, are identified. Of fifteen parameters cited by the Advisory Committee on Reactor Safety in the hearings as being of unproved conservatism, essentially all are reviewed in detail, including, for example, the initial stored fuel energy, fuel rod gas gap conductance, fluid flow rates through broken pipes, metal-water reaction energy release and fuel rod embrittlement, reflood/core-spray heat transfer, and reflooding rates, as well as the adequacy of ECCS analytical models and numerical methods. ,The relative influence of uncertainties in the performance criteria associated with these parameters is assessed. Based upon the relative importance of these parameters, alternative responses to resolution of the ECCS problem are analyzed. The importance of the core reflooding rate in resolving the technical issues of the problem is emphasized. The conservatism of the proposed criteria (current and past) is reviewed. Recommendations are made for improvements in criteria conservatism, especially in the establishment of minimum reflood heat transfer rates (or alternatively, reflooding rates). Several new and/or accelerated research programs and additional large scale testing programs are also recommended. Suggestions are also made for areas in which design improvements would help to achieve greater ECCS reliability