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At least 685 records · Page 38

An investigation of constraint-based component-modeling for knowledge representation in computer-aided conceptual design

Originally, computer programs for engineering design focused on detailed geometric design. Later, computer programs for algorithmically performing the preliminary design of specific well-defined classes of objects became commonplace. However, due to the need for extreme flexibility, it appears unlikely that conventional programming techniques will prove fruitful in developing computer aids for engineering conceptual design. The use of symbolic processing techniques, such as object-oriented programming and constraint propagation, facilitate such flexibility. Object-oriented programming allows programs to be organized around the objects and behavior to be simulated, rather than around fixed sequences of function- and subroutine-calls. Constraint propagation allows declarative statements to be understood as designating multi-directional mathematical relationships among all the variables of an equation, rather than as unidirectional assignments to the variable on the left-hand side of the equation, as in conventional computer programs. The research has concentrated on applying these two techniques to the development of a general-purpose computer aid for engineering conceptual design. Object-oriented programming techniques are utilized to implement a user-extensible database of design components. The mathematical relationships which model both geometry and physics of these components are managed via constraint propagation. In addition, to this component-based hierarchy, special-purpose data structures are provided for describing component interactions and supporting state-dependent parameters. In order to investigate the utility of this approach, a number of sample design problems from the field of aerospace engineering were implemented using the prototype design tool, Rubber Airplane. The additional level of organizational structure obtained by representing design knowledge in terms of components is observed to provide greater convenience to the program user, and to result in a database of engineering information which is easier both to maintain and to extend.

Kolb, Mark A.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 17: A comparison of the technical communication practices of Dutch and US aerospace engineers and scientists

As part of Phase 4 of the NASA/DoD Aerospace Knowledge Diffusion Research Project, two studies were conducted that investigated the technical communications practices of Dutch and U.S. aerospace engineers and scientists. Both studies have the same seven objectives: first, to solicit the opinions of aerospace engineers and scientists regarding the importance of technical communications to their profession; second, to determine the use and production of technical communications by aerospace engineers and scientists; third, to seek their views about the appropriate content of an undergraduate course in technical communications; fourth, to determine aerospace engineers' and scientists' use of libraries, technical information centers, and on-line data bases; fifth, to determine the use and importance of computer and information technology to them; sixth, to determine their use of electronic networks; and seventh, to determine their use of foreign and domestically produced technical reports. A self-administered questionnaire was distributed to aerospace engineers and scientists at the National Aerospace Laboratory (NLR), and NASA Ames Research Center, and the NASA Langley Research Center. The completion rates for the Dutch and U.S. surveys were 55 and 61 percent, respectively. Responses of the Dutch and U.S. participants to selected questions are presented.

Barclay, Rebecca O.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 18: A comparison of the technical communication practices of aerospace engineers and scientists in India and the United States

As part of Phase 4 of the NASA/DoD Aerospace Knowledge Diffusion Research Project, two studies were conducted that investigated the technical communications practices of India and U.S. aerospace engineers and scientists. Both studies have the same seven objectives: first, to solicit the opinions of aerospace engineers and scientists regarding the importance of technical communications to their profession; second, to determine the use and production of technical communications by aerospace engineers and scientists; third, to seek their views about the appropriate content of an undergraduate course in technical communications; fourth, to determine aerospace engineers' and scientists' use of libraries, technical information centers, and on-line data bases; fifth, to determine the use and importance of computer and information technology to them; sixth, to determine their use of electronic networks; and seventh, to determine their use of foreign and domestically produced technical reports. A self-administered questionnaire was distributed to aerospace engineers and scientists at the Indian Institute of Science and the NASA Langley Research Center. The completion rates for the India and U.S. surveys were 48 and 53 percent, respectively. Responses of the India and U.S. participants to selected questions are presented in this report.

Pinelli, Thomas E.↗

User observations on information sharing (corporate knowledge and lessons learned)

The sharing of 'corporate knowledge' and lessons learned in the NASA aerospace community has been identified by Johnson Space Center survey participants as a desirable tool. The concept of the program is based on creating a user friendly information system that will allow engineers, scientists, and managers at all working levels to share their information and experiences with other users irrespective of location or organization. The survey addresses potential end uses for such a system and offers some guidance on the development of subsequent processes to ensure the integrity of the information shared. This system concept will promote sharing of information between NASA centers, between NASA and its contractors, between NASA and other government agencies, and perhaps between NASA and institutions of higher learning.

Montague, Ronald A.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 33: Technical communications practices and the use of information technologies as reported by Dutch and US aerospace engineers

As part of Phase 4 of the NASA/DOD Aerospace Knowledge Diffusion Research Project, two studies were conducted that investigated the technical communications practices of Dutch and U.S. aerospace engineers and scientists. A self-administered questionnaire was distributed to aerospace engineers and scientists at the National Aerospace Laboratory (The Netherlands), and NASA ARC (U.S.), and NASA LaRC (U.S.). This paper presents responses of the Dutch and U.S. participants to selected questions concerning four of the seven project objectives: determining the importance of technical communications to aerospace engineering professionals, investigating the production of technical communications, examining the use and importance of computer and information technology, and exploring the use of electronic networks.

Barclay, Rebecca O.↗

NASDA knowledge-based network planning system

One of the SODS (space operation and data system) sub-systems, NP (network planning) was the first expert system used by NASDA (national space development agency of Japan) for tracking and control of satellite. The major responsibilities of the NP system are: first, the allocation of network and satellite control resources and, second, the generation of the network operation plan data (NOP) used in automated control of the stations and control center facilities. Up to now, the first task of network resource scheduling was done by network operators. NP system automatically generates schedules using its knowledge base, which contains information on satellite orbits, station availability, which computer is dedicated to which satellite, and how many stations must be available for a particular satellite pass or a certain time period. The NP system is introduced.

Yamaya, K.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 41: Technical communication practices of Dutch and US aerospace engineers and scientists: International perspective on aerospace

As part of Phase 4 of the NASA/DOD Aerospace Knowledge Diffusion Research Project, studies were conducted that investigated the technical communications practices of Dutch and U.S. aerospace engineers and scientists. The studies had the following objectives: (1) to solicit the opinions of aerospace engineers and scientists regarding the importance of technical communication to their professions, (2) to determine the use and production of technical communication by aerospace engineers and scientists, (3) to investigate their use of libraries and technical information centers, (4) to investigate their use of and the importance to them of computer and information technology, (5) to examine their use of electronic networks, and (6) to determine their use of foreign and domestically produced technical reports. Self-administered (mail) questionnaires were distributed to Dutch aerospace engineers and scientists at the National Aerospace Laboratory (NLR) in the Netherlands, the NASA Ames Research Center in the U.S., and the NASA Langley Research Center in the U.S. Responses of the Dutch and U.S. participants to selected questions are presented in this paper.

Barclay, Rebecca O.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Paper 40: Technical communications in aerospace education: A study of AIAA student members

This paper describes the preliminary analysis of a survey of the American Institute of Aeronautics and Astronautics (AIAA) student members. In the paper we examine (1) the demographic characteristics of the students, (2) factors that affected their career decisions, (3) their career goals and aspirations, and (4) their training in technical communication and techniques for finding and using aerospace scientific and technical information (STI). We determine that aerospace engineering students receive training in technical communication skills and the use of STI. While those in the aerospace industry think that more training is needed, we believe the students receive the appropriate amount of training. We think that the differences between the amount of training students receive and the perception of training needs is related partially to the characteristics of the students and partially to the structure of the aerospace STI dissemination system. Overall, we conclude that the students' technical communication training and knowledge of STI, while limited by external forces, makes it difficult for students to achieve their career goals.

Kennedy, John M.↗

Knowledge-based systems in Japan

This report summarizes a study of the state-of-the-art in knowledge-based systems technology in Japan, organized by the Japanese Technology Evaluation Center (JTEC) under the sponsorship of the National Science Foundation and the Advanced Research Projects Agency. The panel visited 19 Japanese sites in March 1992. Based on these site visits plus other interactions with Japanese organizations, both before and after the site visits, the panel prepared a draft final report. JTEC sent the draft to the host organizations for their review. The final report was published in May 1993.

Feigenbaum, Edward↗

NASA/DoD Aerospace Knowledge Diffusion Research Project. XXXIII - Technical communications practices and the use of information technologies as reported by Dutch and U.S. aerospace engineers

As part of Phase 4 of the NASA/DOD Aerospace Knowledge Diffusion Research Project, two studies were conducted that investigated the technical communications practices of Dutch and U.S. aerospace engineers and scientists. A self-administered questionnaire was distributed to aerospace engineers and scientists at the National Aerospace Laboratory (The Netherlands), and NASA Ames Research Center (U.S.), and the NASA Langley Research Center (U.S.). This paper presents responses of the Dutch and U.S. participants to selected questions about four of the seven project objectives: determining the importance of technical communications to aerospace engineering professionals, investigating the production of technical communications, examining the use and importance of computer and information technology, and exploring the use of electronic networks.

Barclay, Rebecca O.↗

Present state of knowledge of the upper atmosphere1993: An assessment report, part 2

This document is issued in response to the Clean Air Act Amendment of 1990, Public Law 101-549, which mandates that the National Aeronautics and Space Administration (NASA) and other key agencies submit triennial reports to Congress and the Environmental Protection Agency. NASA is charged with the responsibility to report on the state of our knowledge of the earth's upper atmosphere, particularly the stratosphere. Part 2 (this document) presents summaries of several scientific assessments of our current understanding of the chemical composition and physical structure of the stratosphere, in particular how the abundance and distribution of ozone is predicted to change in the future. These reviews include: (Section B) 'Scientific Assessment of Ozone Depletion: 1991'; (Section C) 'Methyl bromide and the Ozone Layer: A Summary of Current Understanding', published in 1992; (Section D) 'Concentrations, Lifetimes, and Trends of Chlorofluorocarbons (CFC's), Halons, and Related Molecules in the Atmosphere'; (Section E) 'The Atmospheric Effects of Stratospheric Aircraft: Interim Assessment Report of the NASA High-Speed Research Program'; (Section F) 'Chemical Kinetics and Photochemical Data for Use in Stratospheric Modeling'; and (Section G) a list of the contributors to this report.

Kurylo, Michael J.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 30: Computer-Mediated Communication (CMC) and the communication of technical information in aerospace

This research used survey research to examine the use of communication media in general and electronic media specifically in the U.S. aerospace industry. The survey population included 1,006 randomly selected U.S. aerospace engineers and scientists who belong to the American Institute of Aeronautics and Astronautics (AIAA). Survey data were compared with qualitative information obtained from 32 AIAA members in telephone and face-to-face conversations. The Information Processing (IP) model developed by Tushman and Nadler and Daft and Lengel constituted the study's theoretical basis. This research analyzed responses regarding communication methods of U.S. aerospace engineers and scientists who create use and disseminate aerospace knowledge and explored selected contextual environmental variables related to media use and effective performance. The results indicate that uncertainty is significantly reduced in environments when levels of analyzability are high. When uncertainty is high there is significantly more use of electronic media. However no relation was found between overall effectiveness and media use in environments stratified by levels by analyzability or equivocality. The results indicate modest support for the influences of uncertainty and analyzability on electronic media use. Although most respondents reported that electronic networks are important for their work the data suggest that there are sharply disparate levels of use.

Murphy, Daniel J.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 26: The technical communication practices of aerospace engineering students: Results of the phase 3 AIAA National Student Survey

This report describes similarities and differences between undergraduate and graduate engineering students in the context of two general aspects of the educational experience. First, we explore the extent to which students differ regarding the factors that lead to the choice of becoming an engineer, current satisfaction with that choice, and career-related goals and objectives. Second, we look at the technical communication practices, habits, and training of aerospace engineering students. The reported data were obtained from a survey of student members of the American Institute of Aeronautics and Astronautics (AIAA). The survey was undertaken as a phase 3 activity of the NASA/DoD Aerospace Knowledge Diffusion Research Project. Data are reported for the following categories: student demographics; skill importance, skill training, and skill helpfulness; collaborative writing; computer and information technology use and importance; use of electronic networks; use and importance of libraries and library services; use and importance of information sources and products; use of foreign language technical reports; and foreign language (reading and speaking) skills.

Pinelli, Thomas E.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 29: A comparison of the technical communications practices of Japanese and US aerospace engineers and scientists

As part of Phase 4 of the NASA/DoD Aerospace Knowledge Diffusion Research Project, two studies were conducted that investigated the technical communications practices of Japanese and U.S. aerospace engineers and scientists. Both studies have the same seven objectives: first, to solicit the opinions of aerospace engineers and scientists regarding the importance of technical communications to their profession; second, to determine the use and production of technical communications by aerospace engineers and scientists; third; to seek their views about the appropriate content of an undergraduate course in technical communications; fourth, to determine aerospace engineers' and scientists' use of libraries, technical information centers, and on-line data bases; fifth, to determine the use and importance of computer and information technology to them; sixth, to determine their use of electronic networks; and seventh, to determine their use of foreign and domestically produced technical reports. A self-administered questionnaire was distributed to aerospace engineers and scientists in Japan and at the NASA Ames Research Center and the NASA Langley Research Center. The completion rates for the Japanese and U.S. surveys were 85 and 61 percent, respectively. Responses of the Japanese and U.S. participants to selected questions are presented in this report.

Pinelli, Thomas E.↗

Knowledge based translation and problem solving in an intelligent individualized instruction system

An Intelligent Individualized Instruction I(sup 3) system is being built to provide computerized instruction. We present the roles of a translator and a problem solver in an intelligent computer system. The modular design of the system provides for easier development and allows for future expansion and maintenance. CLIPS modules and classes are utilized for the purpose of the modular design and inter module communications. CLIPS facts and rules are used to represent the system components and the knowledge base. CLIPS provides an inferencing mechanism to allow the I(sup 3) system to solve problems presented to it in English.

Jung, Namho↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 28: The technical communication practices of aerospace engineering and science students: Results of the phase 4 cross-national surveys

This report describes similarities and differences between undergraduate and graduate aerospace engineering and science students in the context of two general aspects of the educational experience. First, we explore the extent to which students differ regarding the factors that lead to the choice of becoming an aerospace engineer or a scientist, current satisfaction with that choice, and career-related goals and objectives. Second, we look at the technical communication skills, practices, habits, and training of aerospace engineering and science students. The reported data were obtained from a survey of students enrolled in aerospace engineering and science programs at universities in India, Japan, Russia, and the United Kingdom. The surveys were undertaken as part of the NASA/DOD Aerospace Knowledge Diffusion Research Project. Data are reported for the following categories: student demographics; skill importance, skill training, and skill helpfulness; collaborative writing; computer and information technology use and importance, use of electronic networks; use and importance of libraries and library services; use and importance of information sources and products; use of foreign language technical reports; and foreign language (reading and speaking) skills.

Pinelli, Thomas E.↗

NASA/DOD Aerospace Knowledge Diffusion Research Project. Report 27: The technical communication practices of engineering and science students: Results of the phase 3 academic surveys

This report describes similarities and differences between undergraduate and graduate engineering science students in the context of two general aspects of the educational experience. First, we explore the extent to which students differ regarding the factors that lead to the choice of becoming an engineer or a scientist, current satisfaction with that choice, and career-related goals and objectives. Second, we look at the technical communication practices, habits, and training of engineers and science (Physics) students. The reported data were obtained from a survey of students enrolled in the College of Engineering at the University of Illinois at Urbana-Champaign, Bowling Green State University, and Texas A&M University. The survey was undertaken as part of the NASA/DOD Aerospace Knowledge Diffusion Research Project. Data are reported for the following categories: student demographics; skill importance, skill training, and skill helpfulness; collaborative writing; computer and information technology use and importance, use of electronic networks; use and importance of libraries and library services; use and importance of information sources and products; use of foreign technical reports; and foreign language (reading and speaking) skills.

Pinelli, Thomas E.↗

Status of LDEF contributions to current knowledge of meteoroid and manmade debris environments and their effects on spacecraft in LEO

The analyses, which are currently being performed by the LDEF Meteoroid and Debris Principal Investigators and the other LDEF Meteoroid and Debris Special Investigation Group Members of the data derived from the seven meteoroid and debris experiments that were flown on the LDEF and the post-retrieval scans of the impact sites found on other experiment and LDEF surfaces will, when they are completed, result in many very significant contributions to our knowledge of the meteoroid and debris status report on the analyses that have been performed to date and the preliminary contributions indicated by these analyses. This paper also discusses new questions that have been raised by the completed analyses regarding these environments and their effects on spacecraft.

Kinard, William H.↗