1,283 research outputs found

    SE and I system testability: The key to space system FDIR and verification testing

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    The key to implementing self-diagnosing design is a systems engineering task focused on design for testability concurrent with design for functionality. The design for testability process described here is the product of several years of DOD study and experience. Its application to the space station has begun on Work Package II under NASA and McDonnell direction. Other work package teams are being briefed by Harris Corporation with the hope of convincing them to embrace the process. For the purpose of this discussion the term testability is used to describe the systems engineering process by which designers can assure themselves and their reviewers that their designs are TESTABLE, that is they will support the downstream process of determining their functionality. Due to the complexity and density of present-day state-of-the-art designs, such as pipeline processors and high-speed integrated circuit technology, testability feature design is a critical requirement of the functional design process. A systematic approach to Space systems test and checkout as well as fault detection fault isolation reconfiguration (FDFIR) will minimize operational costs and maximize operational efficiency. An effective design for the testability program must be implemented by all contractors to insure meeting this objective. The process is well understood and technology is here to support it

    Considerations for a design and operations knowledge support system for Space Station Freedom

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    Engineering and operations of modern engineered systems depend critically upon detailed design and operations knowledge that is accurate and authoritative. A design and operations knowledge support system (DOKSS) is a modern computer-based information system providing knowledge about the creation, evolution, and growth of an engineered system. The purpose of a DOKSS is to provide convenient and effective access to this multifaceted information. The complexity of Space Station Freedom's (SSF's) systems, elements, interfaces, and organizations makes convenient access to design knowledge especially important, when compared to simpler systems. The life cycle length, being 30 or more years, adds a new dimension to space operations, maintenance, and evolution. Provided here is a review and discussion of design knowledge support systems to be delivered and operated as a critical part of the engineered system. A concept of a DOKSS for Space Station Freedom (SSF) is presented. This is followed by a detailed discussion of a DOKSS for the Lyndon B. Johnson Space Center and Work Package-2 portions of SSF

    Test, Control and Monitor System (TCMS) operations plan

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    The purpose is to provide a clear understanding of the Test, Control and Monitor System (TCMS) operating environment and to describe the method of operations for TCMS. TCMS is a complex and sophisticated checkout system focused on support of the Space Station Freedom Program (SSFP) and related activities. An understanding of the TCMS operating environment is provided and operational responsibilities are defined. NASA and the Payload Ground Operations Contractor (PGOC) will use it as a guide to manage the operation of the TCMS computer systems and associated networks and workstations. All TCMS operational functions are examined. Other plans and detailed operating procedures relating to an individual operational function are referenced within this plan. This plan augments existing Technical Support Management Directives (TSMD's), Standard Practices, and other management documentation which will be followed where applicable

    Public policies and food security and family farming networks: contributions to the construction of effectiveness indicators.

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    This work presents a methodology for investigating the performance of public politics regarding food security networks formed in Brazilian municipalities aimed at increasing income and employment in familiar farming. These programs need to further develop the methodologies used for studying their efficiency so that they can reach a new stage in the improvement and use of management tools thereby achieving beteer results of social inclusion and/or food security. This paper constitutes a first effort to bring together indicators for the evaluation of the efficiency of public politicies

    Test, Control and Monitor System maintenance plan

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    The maintenance requirements for Test, Control, and Monitor System (TCMS) and the method for satisfying these requirements prior to First Need Date (FND) of the last TCMS set are described. The method for satisfying maintenance requirements following FND of the last TCMS set will be addressed by a revision to this plan. This maintenance plan serves as the basic planning document for maintenance of this equipment by the NASA Payloads Directorate (CM) and the Payload Ground Operations Contractor (PGOC) at KSC. The terms TCMS Operations and Maintenance (O&M), Payloads Logistics, TCMS Sustaining Engineering, Payload Communications, and Integrated Network Services refer to the appropriate NASA and PGOC organization. For the duration of their contract, the Core Electronic Contractor (CEC) will provide a Set Support Team (SST). One of the primary purposes of this team is to help NASA and PGOC operate and maintain TCMS. It is assumed that SST is an integral part of TCMS O&M. The purpose of this plan is to describe the maintenance concept for TCMS hardware and system software in order to facilitate activation, transition planning, and continuing operation. When software maintenance is mentioned in this plan, it refers to maintenance of TCMS system software

    Common global architecture applied to automobile electrical distribution systems

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    Thesis (S.M. in System Design and Management)--Massachusetts Institute of Technology, Engineering Systems Division, System Design and Management Program, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 111-112).Electrical and electronic components have a prominent role in today's vehicles. Particularly during the last two decades, functionality has been added at an exponential rate, resulting in increased complexity, especially of the Electrical Distribution System (EDS), which is the backbone of the Electrical and Electronic System (EES). Increased content and complexity of electrical systems, together with pressure to reduce the design cycle time - to bring a larger variety of products to the market and at a faster pace - are forcing car companies to re-evaluate their existing electrical development processes. One of the ways that car makers have devised to accomplish this is a common EES architecture strategy, which consists in combining communization, standardization, reusability and best practices to create flexible EES architectural concepts that will be used in a higher number of derivative vehicles. This common architecture has several benefits, the most important being: reduction of development costs and time, which translates in less time for putting the products in the market; architecture, concepts and components reuse; rapid platform modifications, to adapt to market changes and regional preferences. The EES architecture choice for a vehicle is the result of the implementation of the desired functions in hardware and software. Many considerations need to be taken into account: costs, network capabilities, modularity, manufacturing, energy management, weight, among several others. The present work aims to explain these considerations, as well as the elements of the common EES, and in particular their impact on the EDS. Another important aspect for the successful implementation of the common architecture is the EDS development process. Despite the availability of a wide range of software tools, the current EDS approach is intensely manual, relying on design experts to define and maintain the interrelationships and complexities of the core design definition. There is a need to redefine the process, from concept to manufacture using a systems engineering approach, which would yield key benefits, like shorten development time, produce accurate harness manufacturing prints, reduce wiring costs by synchronizing all input and output data. An analysis of the tools and methods for design and validation of wire harnesses will be presented in the last two chapters of this thesis.by Marcia E. Azpeitia Camacho.S.M.in System Design and Managemen

    RICIS Symposium 1992: Mission and Safety Critical Systems Research and Applications

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    This conference deals with computer systems which control systems whose failure to operate correctly could produce the loss of life and or property, mission and safety critical systems. Topics covered are: the work of standards groups, computer systems design and architecture, software reliability, process control systems, knowledge based expert systems, and computer and telecommunication protocols

    SOHO Mission Interruption Joint NASA/ESA Investigation Board

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    Contact with the SOlar Heliospheric Observatory (SOHO) spacecraft was lost in the early morning hours of June 25, 1998, Eastern Daylight Time (EDT), during a planned period of calibrations, maneuvers, and spacecraft reconfigurations. Prior to this the SOHO operations team had concluded two years of extremely successful science operations. A joint European Space Agency (ESA)/National Aeronautics and Space Administration (NASA) engineering team has been planning and executing recovery efforts since loss of contact with some success to date. ESA and NASA management established the SOHO Mission Interruption Joint Investigation Board to determine the actual or probable cause(s) of the SOHO spacecraft mishap. The Board has concluded that there were no anomalies on-board the SOHO spacecraft but that a number of ground errors led to the major loss of attitude experienced by the spacecraft. The Board finds that the loss of the SOHO spacecraft was a direct result of operational errors, a failure to adequately monitor spacecraft status, and an erroneous decision which disabled part of the on-board autonomous failure detection. Further, following the occurrence of the emergency situation, the Board finds that insufficient time was taken by the operations team to fully assess the spacecraft status prior to initiating recovery operations. The Board discovered that a number of factors contributed to the circumstances that allowed the direct causes to occur. The Board strongly recommends that the two Agencies proceed immediately with a comprehensive review of SOHO operations addressing issues in the ground procedures, procedure implementation, management structure and process, and ground systems. This review process should be completed and process improvements initiated prior to the resumption of SOHO normal operations

    Fourth Conference on Artificial Intelligence for Space Applications

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    Proceedings of a conference held in Huntsville, Alabama, on November 15-16, 1988. The Fourth Conference on Artificial Intelligence for Space Applications brings together diverse technical and scientific work in order to help those who employ AI methods in space applications to identify common goals and to address issues of general interest in the AI community. Topics include the following: space applications of expert systems in fault diagnostics, in telemetry monitoring and data collection, in design and systems integration; and in planning and scheduling; knowledge representation, capture, verification, and management; robotics and vision; adaptive learning; and automatic programming
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