Showing papers on "System integration published in 1984"

Photovoltaic power conditioning subsystem: state of the art and development opportunities

Abstract: Photovoltaic systems, the state of the art of power conditioning subsystem components, and the design and operational interaction between photovoltaic systems and host utilities are detailed in this document Major technical issues relating to the design and development of power conditioning systems for photovoltaic application are considered; these include: (1) standards, guidelines, and specifications; (2) cost effective hardware design; (3) impact of advanced components on power conditioning development; (4) protection and safety; (5) quality of power; (6) system efficiency; and (7) system integration with the host utility Theories of harmonic distortion and reactive power flow are discussed, and information about power conditioner hardware and manufacturers is provided

Impact of flight systems integration on future aircraft design

Abstract: Integrations trends in aircraft are discussed with an eye to manifestations in future aircraft designs through interdisciplinary technology integration. Current practices use software changes or small hardware fixes to solve problems late in the design process, e.g., low static stability to upgrade fuel efficiency. A total energy control system has been devised to integrate autopilot and autothrottle functions, thereby eliminating hardware, reducing the software, pilot workload, and cost, and improving flight efficiency and performance. Integrated active controls offer reduced weight and larger payloads for transport aircraft. The introduction of vectored thrust may eliminate horizontal and vertical stabilizers, and location of the thrust at the vehicle center of gravity can provide vertical takeoff and landing capabilities. It is suggested that further efforts will open a new discipline, aeroservoelasticity, and tests will become multidisciplinary, involving controls, aerodynamics, propulsion and structures.

Software reliability measurement: prediction, estimation, and assessment

Abstract: In order to keep pace with the rising demands for DoD system acquisitions, software must be made more reliable. One step toward accomplishing this goal is to improve software reliability measurement so that we may better see where we stand today in order to identify where improvements need to be made for tomorrow's systems. This paper recommends a comprehensive measurement scheme covering both software products and processes over the software acquisition life cycle. Three main categories of measurement are proposed: 1. (1) reliability prediction during software development; 2. (2) reliability estimation during system integration and testing; and 3. (3) reliability assessment after deployment in the operational environment. A summary of two current reliability measurement techniques, software metrics and stochastic software reliability models, is also presented.

The use of an engineering database for system integration

Abstract: Integrated CAE implies the intimate interlinking of many diverse engineering systems. This could be achieved on a piecemeal basis with data distributed over the various systems and managed in local databases. However, a much more elegant solution for system integration, and certainly the only viable long-term one, is through the medium of a central engineering database. This database must store all design and manufacturing data and support multidiscipline multilevel access. More importantly it must store geometric data in a canonical form, thus insulating the company and the data from the vagaries of CAD systems.

More electronics in detroit's 1985 models

Abstract: After years of experience with electronic devices and systems in cars, automobile manufacturers are moving toward a more mature, integrated-systems approach to design. In some 1985 cars microprocessors communicate with each other, sharing input data, to provide more precise control of car functions. Single instruments are programmed to give multiple readouts. And instruments, on-board diagnostics, and navigational systems are designed to share one overall display. The paper reviews the innovations in 1985 cars giving particular attention to systems integration, travel aid systems, improved diagnostics aid servicing, engine control, load leveling suspensions, advanced displays, and new electronic antilock braking systems.

Local Area Networks: Rationalizing the Management of Microcomputers.

Abstract: Four management functions are required to effectively manage all computing resources: resource management, security/user access management, software management, and communications facilitation. The functions are well developed for mainframe and mini computer systems, but their application to the microcomputer environment has not been well addressed. Three management approaches to managing microcomputers are: laissez-faire, central coordination, and system integration. System integration provides the management environment most like that of mainframe systems, thereby allowing existing management tools to be used. The system integration approach requires the development of a local area network that includes features not yet widely available in commercial products.

Air Revitalization System Integration

Abstract: This paper presents a status review of Spacecraft Air Revitalization System (ARS) integration using regenerable techniques. The paper addresses concepts of integration of individual subsystems into an Air Revitalization System, as well as integration of components within subsystems. An ARS design is presented based on the Electrochemical Depolarized Carbon Dioxide Concentrator Subsystem, the Sabatier Carbon Dioxide Reduction Subsystem, the Static Feed Water Electrolysis Subsystem, a condensing Humidity Control Subsystem, and a Water Handling Subsystem to perform the functions of CO2 removal, CO2 reduction, O2 generation, humidity control and by-product water distribution, respectively. The paper also highlights the numerous advantages of this integration. Trace contaminant control and the nitrogen supply are not included in the ARS described in this paper.

Definition of ground test for Large Space Structure (LSS) control verification

Abstract: An overview for the definition of a ground test for the verification of Large Space Structure (LSS) control is given. The definition contains information on the description of the LSS ground verification experiment, the project management scheme, the design, development, fabrication and checkout of the subsystems, the systems engineering and integration, the hardware subsystems, the software, and a summary which includes future LSS ground test plans. Upon completion of these items, NASA/Marshall Space Flight Center will have an LSS ground test facility which will provide sufficient data on dynamics and control verification of LSS so that LSS flight system operations can be reasonably ensured.

Systems engineering - Space Telescope project

Abstract: At midpoint in the development of the Space Telescope (ST), a review process was conducted which determined that much benefit could be derived from an expanded systems engineering effort. The Systems Engineering Office thus established is responsible for the running of a management information system whose functions encompass design change control and the implementation of a maintenance and refurbishment program. By these means, interface hardware/software incompatibilities between critical ST modules and subsystems have been revealed and corrected.

An interactive approach to solids modelling

Abstract: Solids modelling techniques offer great promise for CAD. To enhance the productivity benefits associated with CAD using solids modelling, unique developments have been undertaken to integrate solids with existing software capabilities. When this software integration is combined with specially designed hardware, a truly interactive environment is created. This interactivity allows the CAD user to perform productively tasks previously considered beyond the scope of interactive graphics.

Information systems - Issues in global habitability

Abstract: The present investigation is concerned with fundamental issues, related to information considerations, which arise in an interdisciplinary approach to questions of global habitability. Information system problems and issues are illustrated with the aid of an example involving biochemical cycling and biochemical productivity. The estimation of net primary production (NPP) as an important consideration in the overall global habitability issue is discussed. The NPP model requires three types of data, related to meteorological information, a land surface inventory, and the vegetation structure. Approaches for obtaining and processing these data are discussed. Attention is given to user requirements, information system requirements, workstations, network communications, hardware/software access, and data management.

Design versus manufacturing data base management requirements

Abstract: Data base management systems are valuable manufacturing and design tools as these disciplines are exceptionally information intensive, requiring precise organization and control of data processing and utilization. One such data base manager is the IPAD* system, which was originally developed to support the design process but was expanded to incorporate the additional needs of manufacturing. To set the stage, an overview of the design and manufacturing process is presented. The different functions of computers in these processes are then discussed. Finally, the design and manufacturing requirements for a data base manager are compared and contrasted.

A Database Management Approach to CAD/CAM Systems Integration

Abstract: Facilitating the communication between different CAD/CAM systems is rapidly becoming an important issue, as more such systems reach the market. A solution to the communication problem can be found if it is considered part of the more general problem of managing the complex information associated with the representation of physical artifacts and environments in the memory of computers, thereby accounting for the operators that are used for accessing the data as well as the data itself. Database management systems have provided powerful solutions to information management problems in a variety of disciplines and enjoy a broad and rigorous research foundation. If the techniques, methods and systems that were developed for database management could be utilized for CAD/CAM integration, they would save a considerable duplication of effort, enhance the integrity of the data, and bring to bear the results and advances that have been achieved through a long period of hard work.

Software modifications to the Demonstration Advanced Avionics Systems (DAAS)

Abstract: Critical information required for the design of integrated avionics suitable for generation aviation is applied towards software modifications for the Demonstration Advanced Avionics System (DAAS). The program emphasizes the use of data busing, distributed microprocessors, shared electronic displays and data entry devices, and improved functional capability. A demonstration advanced avionics system (DAAS) is designed, built, and flight tested in a Cessna 402, twin engine, general aviation aircraft. Software modifications are made to DAAS at Ames concurrent with the flight test program. The changes are the result of the experience obtained with the system at Ames, and the comments of the pilots who evaluated the system.

NATO III Satellite Communications System Control

Abstract: The system control concepts to improve channel utilization and the recent progress of the design, development, and integration of the control subsystem for the satellite communications network are reported. The network operates with a large number of single-destin ation radio frequency carriers to provide voice, low-speed telegraph, and medium-speed data circuits. A power control algorithm to keep the link quality at the desired nominal level and a traffic control algorithm allowing reconfiguration of the network to accommodate fluctuating traffic are presented. The system control software development cycle, consisting of design, which includes functional decomposition and software module structure, integration and testing phases, is discussed. Various functional flow diagrams are provided illustrating the information interfaces to external communications, the network data base, and the physical devices. An example illustrating the performance of power control and traffic control software is presented.