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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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NASA NTRS1990

Cost and quality planning for large NASA programs

The Software Cost and Quality Engineering methodology developed over the last two decades at IBM Federal Sector Div. is used to plan the NASA Space Station Data Management System (DMS). An ongoing project to capture this methodology, which is built on a foundation of experiences and lessons learned, has resulted in the development of a PC-based tool that integrates cost and quality forecasting methodologies and data in a consistent manner. This tool, Software Cost and Quality Engineering Starter Set (SCQESS), is being used to assist in the DMS costing exercises. At the same time, DMS planning serves as a forcing function and provides a platform for the continuing, iterative development, calibration, and validation and verification of SCQESS. The data that forms the cost and quality engineering data base is derived from more than 17 years of development of NASA Space Shuttle software, ranging from low criticality, low complexity support tools to highly complex and highly critical onboard software.

Rone, Kyle Y.↗

NASA NTRS1992

A brief overview of computational structures technology related activities at NASA Lewis Research Center

The presentation gives a partial overview of research and development underway in the Structures Division of LeRC, which collectively is referred to as the Computational Structures Technology Program. The activities in the program are diverse and encompass four major categories: (1) composite materials and structures; (2) probabilistic analysis and reliability; (3) design optimization and expert systems; and (4) computational methods and simulation. The approach of the program is comprehensive and entails exploration of fundamental theories of structural mechanics to accurately represent the complex physics governing engine structural performance, formulation, and implementation of computational techniques and integrated simulation strategies to provide accurate and efficient solutions of the governing theoretical models by exploiting the emerging advances in computer technology, and validation and verification through numerical and experimental tests to establish confidence and define the qualities and limitations of the resulting theoretical models and computational solutions. The program comprises both in-house and sponsored research activities. The remainder of the presentation provides a sample of activities to illustrate the breadth and depth of the program and to demonstrate the accomplishments and benefits that have resulted.

Hopkins, Dale A.↗

NASA NTRS1990

Fly-by-light technology development plan

The driving factors and developments which make a fly-by-light (FBL) viable are discussed. Documentation, analyses, and recommendations are provided on the major issues pertinent to facilitating the U.S. implementation of commercial FBL aircraft before the turn of the century. Areas of particular concern include ultra-reliable computing (hardware/software); electromagnetic environment (EME); verification and validation; optical techniques; life-cycle maintenance; and basis and procedures for certification.

Todd, J. R.↗

NASA NTRS1992

Rapid development of the X-31 simulation to support flight-testing

The X-31 Enhanced Fighter Maneuverability Program has been recognized to form the International Test Organization, with the NASA Dryden Flight Research Facility (NASA-Dryden) as the responsible test organization. The two X-31 research aircraft and engineering support personnel were colocated at NASA-Dryden, with flight test operations beginning in Apr. 1992. Therefore, rapid development of a hardware-in-the-loop simulation was needed to support the flight test operations at NASA-Dryden, and to perform verification and validation of flight control software. The X-31 simulation system requirements, distributed simulation system architecture, simulation components math models to the visual system, and the advanced capabilities the X-31 simulation provides. In addition, unique software tools and the methods used to rapidly develop this simulation system will be highlighted.

Mackall, Dale↗

NASA NTRS1991

Safety

Software requirements, design, implementation, verification and validation, and especially management are affected by the need to produce safe software. This paper discusses the changes in the software life cycle that are necessary to ensure that software will execute without resulting in unacceptable risk. Software is being used increasingly to monitor and control safety-critical processes in which a run-time failure or error could result in unacceptable losses such as death, injury, loss of property, or environmental harm. Examples of such processes maybe found in transportation, energy, aerospace, basic industry, medicine, and defense systems.

Leveson, Nancy G.↗

NASA NTRS1992

Fault management for the Space Station Freedom control center

This paper describes model based reasoning fault isolation in complex systems using automated digraph analysis. It discusses the use of the digraph representation as the paradigm for modeling physical systems and a method for executing these failure models to provide real-time failure analysis. It also discusses the generality, ease of development and maintenance, complexity management, and susceptibility to verification and validation of digraph failure models. It specifically describes how a NASA-developed digraph evaluation tool and an automated process working with that tool can identify failures in a monitored system when supplied with one or more fault indications. This approach is well suited to commercial applications of real-time failure analysis in complex systems because it is both powerful and cost effective.

Clark, Colin↗

NASA NTRS1992

A rule-based system for real-time analysis of control systems

An approach to automate the real-time analysis of flight critical health monitoring and system status is being developed and evaluated at the NASA Dryden Flight Research Facility. A software package was developed in-house and installed as part of the extended aircraft interrogation and display system. This design features a knowledge-base structure in the form of rules to formulate interpretation and decision logic of real-time data. This technique has been applied for ground verification and validation testing and flight testing monitoring where quick, real-time, safety-of-flight decisions can be very critical. In many cases post processing and manual analysis of flight system data are not required. The processing is described of real-time data for analysis along with the output format which features a message stack display. The development, construction, and testing of the rule-driven knowledge base, along with an application using the X-31A flight test program, are presented.

Larson, Richard R.↗

NASA NTRS1992

Knowledge-based system V and V in the Space Station Freedom program

Knowledge Based Systems (KBS's) are expected to be heavily used in the Space Station Freedom Program (SSFP). Although SSFP Verification and Validation (V&V) requirements are based on the latest state-of-the-practice in software engineering technology, they may be insufficient for Knowledge Based Systems (KBS's); it is widely stated that there are differences in both approach and execution between KBS V&V and conventional software V&V. In order to better understand this issue, we have surveyed and/or interviewed developers from sixty expert system projects in order to understand the differences and difficulties in KBS V&V. We have used this survey results to analyze the SSFP V&V requirements for conventional software in order to determine which specific requirements are inappropriate for KBS V&V and why they are inappropriate. Further work will result in a set of recommendations that can be used either as guidelines for applying conventional software V&V requirements to KBS's or as modifications to extend the existing SSFP conventional software V&V requirements to include KBS requirements. The results of this work are significant to many projects, in addition to SSFP, which will involve KBS's.

Kelley, Keith↗

NASA NTRS1991

The design of a common lunar lander

The Austin Cynthesis Corporation was formed to respond to a Request for Proposal for the design of a Common Lunar Lander (CLL) capable of carrying lightweight (less than 500 kg), unspecified payload to the moon. This Final Design Report Document includes information on the requirements for the design project; the ideas proposed as solutions to the design problem; the work which has been completed in support of the design effort; justifications, validations, and verifications of decisions made during the project; and suggestions for future work to be done in support of the project. A project schedule, including current status of the items included on the schedule, as well as cost and management summaries is also included.

Driggers, Dan↗

NASA NTRS1991

Autonomous rendezvous and capture system design

The presentation addressed the different tradeoffs necessary to get an automated rendezvous and capture system design that meets the current requirements. The topics covered are piloted versus autonomous capture design considerations, navigation sensor selection tradeoffs, control algorithm design requirements and concepts, performance evaluation through simulation, system mission readiness verification and validation, and advanced AR&C control system technologies.

Dabney, Richard↗

NASA NTRS1993

TARGET: Rapid Capture of Process Knowledge

TARGET (Task Analysis/Rule Generation Tool) represents a new breed of tool that blends graphical process flow modeling capabilities with the function of a top-down reporting facility. Since NASA personnel frequently perform tasks that are primarily procedural in nature, TARGET models mission or task procedures and generates hierarchical reports as part of the process capture and analysis effort. Historically, capturing knowledge has proven to be one of the greatest barriers to the development of intelligent systems. Current practice generally requires lengthy interactions between the expert whose knowledge is to be captured and the knowledge engineer whose responsibility is to acquire and represent the expert's knowledge in a useful form. Although much research has been devoted to the development of methodologies and computer software to aid in the capture and representation of some types of knowledge, procedural knowledge has received relatively little attention. In essence, TARGET is one of the first tools of its kind, commercial or institutional, that is designed to support this type of knowledge capture undertaking. This paper will describe the design and development of TARGET for the acquisition and representation of procedural knowledge. The strategies employed by TARGET to support use by knowledge engineers, subject matter experts, programmers and managers will be discussed. This discussion includes the method by which the tool employs its graphical user interface to generate a task hierarchy report. Next, the approach to generate production rules for incorporation in and development of a CLIPS based expert system will be elaborated. TARGET also permits experts to visually describe procedural tasks as a common medium for knowledge refinement by the expert community and knowledge engineer making knowledge consensus possible. The paper briefly touches on the verification and validation issues facing the CLIPS rule generation aspects of TARGET. A description of efforts to support TARGET's interoperability issues on PCs, Macintoshes and UNIX workstations concludes the paper.

Ortiz, C. J.↗

NASA NTRS1993

Multi-viewpoint clustering analysis

In this paper, we address the feasibility of partitioning rule-based systems into a number of meaningful units to enhance the comprehensibility, maintainability and reliability of expert systems software. Preliminary results have shown that no single structuring principle or abstraction hierarchy is sufficient to understand complex knowledge bases. We therefore propose the Multi View Point - Clustering Analysis (MVP-CA) methodology to provide multiple views of the same expert system. We present the results of using this approach to partition a deployed knowledge-based system that navigates the Space Shuttle's entry. We also discuss the impact of this approach on verification and validation of knowledge-based systems.

Mehrotra, Mala↗

NASA NTRS1992

Rapid development of the X-31 simulation to support flight-testing

Mackall, Dale↗

NASA NTRS1991

Systems integration test laboratory - Application and experiences

The experiences gained from the development of the X-29 aircraft's digital flight control system is discussed. The master test plan, validation testing, verification testing, and flight hardware testing of the system are briefly reviewed, and the test facilities are described. Simulator verification and results are summarized.

Rimer, Melvyn↗

NASA NTRS1993

Real-time automated failure analysis for on-orbit operations

A system which is to provide real-time failure analysis support to controllers at the NASA Johnson Space Center Control Center Complex (CCC) for both Space Station and Space Shuttle on-orbit operations is described. The system employs monitored systems' models of failure behavior and model evaluation algorithms which are domain-independent. These failure models are viewed as a stepping stone to more robust algorithms operating over models of intended function. The described system is designed to meet two sets of requirements. It must provide a useful failure analysis capability enhancement to the mission controller. It must satisfy CCC operational environment constraints such as cost, computer resource requirements, verification, and validation. The underlying technology and how it may be used to support operations is also discussed.

Kirby, Sarah↗

NASA NTRS1993

Horton, pipe hydraulics, and the atmospheric boundary layer (The Robert E. Horton Memorial Lecture)

The early stages of Horton's scientific career which provided the opportunity and stimulus to delve into the origins of some contemporary concepts on the atmospheric boundary layer are reviewed. The study of Saph and Schoder provided basis for the experimental verification and validation of similarity by Blasius, Staton and Pannel, and for the subsequent developments that led to the present understanding of the turbulent boundary layer. Particular attention is given to incorporation of similarity and scaling in the analysis of turbulent flow.

Brutsaert, Wilfried↗

NASA NTRS1991

NASA software documentation standard software engineering program

The NASA Software Documentation Standard (hereinafter referred to as Standard) can be applied to the documentation of all NASA software. This Standard is limited to documentation format and content requirements. It does not mandate specific management, engineering, or assurance standards or techniques. This Standard defines the format and content of documentation for software acquisition, development, and sustaining engineering. Format requirements address where information shall be recorded and content requirements address what information shall be recorded. This Standard provides a framework to allow consistency of documentation across NASA and visibility into the completeness of project documentation. This basic framework consists of four major sections (or volumes). The Management Plan contains all planning and business aspects of a software project, including engineering and assurance planning. The Product Specification contains all technical engineering information, including software requirements and design. The Assurance and Test Procedures contains all technical assurance information, including Test, Quality Assurance (QA), and Verification and Validation (V&V). The Management, Engineering, and Assurance Reports is the library and/or listing of all project reports.

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NASA NTRS1993

Earth system dynamics: The interrelation of atmospheric, ocean and solid earth dynamics

The research work performed during the time period 16 Oct. 1992 through 31 Dec. 1993 is summarized. The overall research activity, including a list of the major findings of the EOS IDS research to date, is described, the publications and presentations are listed, and a budget request for the subsequent year is attached. Specifically, the report covers: EOS panel activities; major findings of research; team member contributions; new research directions; EOS restructuring effect; changes in requirements; plans for using existing data; collaborations with other EOS and non-EOS investigations; EOS instrument team interaction; instrument development verification and validation; interaction with EOSDIS and DAAC's; team coordination; overall management; summary of response to site review questions and comments; science computing facility; and additional new research activities.

Tapley, Byron D.↗