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Advances in Software Tools for Pre-processing and Post-processing of Overset Grid Computations

Recent developments in three pieces of software for performing pre-processing and post-processing work on numerical computations using overset grids are presented. The first is the OVERGRID graphical interface which provides a unified environment for the visualization, manipulation, generation and diagnostics of geometry and grids. Modules are also available for automatic boundary conditions detection, flow solver input preparation, multiple component dynamics input preparation and dynamics animation, simple solution viewing for moving components, and debris trajectory analysis input preparation. The second is a grid generation script library that enables rapid creation of grid generation scripts. A sample of recent applications will be described. The third is the OVERPLOT graphical interface for displaying and analyzing history files generated by the flow solver. Data displayed include residuals, component forces and moments, number of supersonic and reverse flow points, and various dynamics parameters.

Chan, William M.↗

Multimission Modular Spacecraft Ground Support Software System (MMS/GSSS) state-of-the-art computer systems/ compatibility study

The compatibility of the Multimission Modular Spacecraft (MMS) Ground Support Software System (GSSS), currently operational on a ModComp IV/35, with the VAX 11/780 system is discussed. The compatibility is examined in various key areas of the GSSS through the results of in depth testing performed on the VAX 11/780 and ModComp IV/35 systems. The compatibility of the GSSS with the ModComp CLASSIC is presented based upon projections from ModComp supplied literature.

Source record↗

Computational mechanics needs study

In order to assess the needs in computational mechanics over the next decade, we formulated a questionnaire and contacted computational mechanics researchers and users in industry, government, and academia. As expected, we found a wide variety of computational mechanics usage and research. This report outlines the activity discussed with those contacts, as well as that in our own organizations. It should be noted that most of the contacts were made before the recent decline of the defense industry. Therefore, areas which are strongly defense-oriented may decrease in relative importance. In order to facilitate updating of this study, names of a few key researchers in each area are included as starting points for future literature surveys. These lists of names are not intended to represent those persons doing the best research in that area, nor are they intended to be comprehensive. They are, as previously stated, offered as starting points for future literature searches. Overall, there is currently a broad activity in computational mechanics in this country, with the breadth and depth increasing as more sophisticated software and faster computers become more available. The needs and desires of the workers in this field are as diverse as their background and organizational products. There seems to be some degree of software development in any organization (although the level of activity is highly variable from one organization to another) which has any research component in its mission. It seems, however, that there is considerable use of commercial software in almost all organizations. In most industrial research organizations, it appears that very little actual software development is contracted out, but that most is done in-house, using a mixture of funding sources. Government agencies vary widely in the ratio of in-house to out-house ratio. There is a considerable amount of experimental verification in most, but not all, organizations. Generally, the amount of experimental verification is more than we expected. Of all the survey contacts, one or two believe that the resources they are allocated are sufficient, but most do not. Some believe they have only half the resources they need. Some see their resource deficits as short-term, while others see it as a trend which will continue or perhaps worsen. The pessimism is stronger in the defense and aerospace industry. When considering only the nonlinear development efforts, there appears to be an even mix of geometric and material nonlinearity. There is not much particular emphasis in linear analysis unless it is in extension of current analysis capabilities to larger problems. The primary exception is concern about modeling of composites, where proven methodologies have trailed element and computer hardware development. Most of the people we spoke to use finite element techniques, but there is some finite difference and boundary element work ongoing. There is also some interest in multiple methods. Coupling of finite elements and boundary elements appears to be of high interest, since the two analysis types are complementary.

Griffin, O. Hayden, Jr.↗

A regional land use survey based on remote sensing and other data: A report on a LANDSAT and computer mapping project, volume 1

The author has identified the following significant results. New LANDSAT analysis software and linkages with other computer mapping software were developed. Significant results were also achieved in training, communication, and identification of needs for developing the LANDSAT/computer mapping technologies into operational tools for use by decision makers.

Nez, G.↗

Thermal-Radiation Program

Thermal Radiation Analyzer System (TRASYS) computer program is software program having generalized capability to solve equations of radiation-related aspects of thermal-analysis problems. Computes total thermal-radiation environment for spacecraft in orbit. Software calculates internode-radiation-interchange data as well as data on rates of incidence and absorption of heat originating from environmental radiant sources. Provides data of both types in format directly usable by such thermal-analyzer programs as SINDA '85/FLUINT (available from COSMIC, program number MSC-21528). CRAY version of TRASYS (P25) written in FORTRAN 77. Other versions available upon request.

Anderson, Gordon↗

Support for Diagnosis of Custom Computer Hardware

The Coldfire SDN Diagnostics software is a flexible means of exercising, testing, and debugging custom computer hardware. The software is a set of routines that, collectively, serve as a common software interface through which one can gain access to various parts of the hardware under test and/or cause the hardware to perform various functions. The routines can be used to construct tests to exercise, and verify the operation of, various processors and hardware interfaces. More specifically, the software can be used to gain access to memory, to execute timer delays, to configure interrupts, and configure processor cache, floating-point, and direct-memory-access units. The software is designed to be used on diverse NASA projects, and can be customized for use with different processors and interfaces. The routines are supported, regardless of the architecture of a processor that one seeks to diagnose. The present version of the software is configured for Coldfire processors on the Subsystem Data Node processor boards of the Solar Dynamics Observatory. There is also support for the software with respect to Mongoose V, RAD750, and PPC405 processors or their equivalents.

Molock, Dwaine S.↗

Software For Diagnosis Of Parallel Processing

Ames Instrumentation System (AIMS) computer program package of software tools measuring and analyzing performances of parallel-processing application programs. Helps programmer to debug and refine, and to monitor and visualize execution of, parallel-processing application software for Intel iPSC/860 (or equivalent) multicomputer. Performance data collected displayed graphically on computer workstations supporting X-Windows.

Hontalas, Philip↗

SimELIT: A Novel GUI-Based Comprehensive Ion Trajectory Simulation Software for Mass Spectrometry

Ion trajectory simulation in mass spectrometry systems from injection to detection is technically challenging but very important for better understanding the ion dynamics in instrument development. Here, in this work, we present SimELIT (Simulator of Eulerian and Lagrangian Ion Trajectories), a novel ion trajectory simulation platform. SimELIT is built upon a suite of multiphysics solvers compiled into OpenFOAM (an open-source numerical solver library particularly used for computational mechanics), with a simple web-based graphical user interface (GUI) allowing users to define the details of OpenFOAM cases and run simulations. SimELIT is a modular program and can provide extensions of physics (e.g., gas flows, electrodynamic fields) and thus enable ion trajectory simulations from the ion source to detector. The current version (SimELIT) provides two numerical solvers for ion trajectory simulations–(1) a Lagrangian particle tracker in vacuum and (2) a Eulerian ion density solver in background gas in the presence of electric fields. Here, we describe the architecture of SimELIT, including its use of Docker and the React Framework, and demonstrate the computation of ion trajectories of multiple m/z values in a static/linear voltage drop in vacuum (across a 1 m long flight tube). Further, the drift motion of ions under 1 Torr pressure conditions in a static background (N 2 ) gas through a 20 V/cm static electric field is shown. The results produced from SimELIT were compared with SIMION and theoretical estimates. In addition, we report the computation of ion trajectories in electrodynamic fields within a planar FAIMS device operating at atmospheric pressure.

97 MATHEMATICS AND COMPUTING↗

Computational Nanotechnology at NASA Ames Research Center, 1996

Some forms of nanotechnology appear to have enormous potential to improve aerospace and computer systems; computational nanotechnology, the design and simulation of programmable molecular machines, is crucial to progress. NASA Ames Research Center has begun a computational nanotechnology program including in-house work, external research grants, and grants of supercomputer time. Four goals have been established: (1) Simulate a hypothetical programmable molecular machine replicating itself and building other products. (2) Develop molecular manufacturing CAD (computer aided design) software and use it to design molecular manufacturing systems and products of aerospace interest, including computer components. (3) Characterize nanotechnologically accessible materials of aerospace interest. Such materials may have excellent strength and thermal properties. (4) Collaborate with experimentalists. Current in-house activities include: (1) Development of NanoDesign, software to design and simulate a nanotechnology based on functionalized fullerenes. Early work focuses on gears. (2) A design for high density atomically precise memory. (3) Design of nanotechnology systems based on biology. (4) Characterization of diamonoid mechanosynthetic pathways. (5) Studies of the laplacian of the electronic charge density to understand molecular structure and reactivity. (6) Studies of entropic effects during self-assembly. Characterization of properties of matter for clusters up to sizes exhibiting bulk properties. In addition, the NAS (NASA Advanced Supercomputing) supercomputer division sponsored a workshop on computational molecular nanotechnology on March 4-5, 1996 held at NASA Ames Research Center. Finally, collaborations with Bill Goddard at CalTech, Ralph Merkle at Xerox Parc, Don Brenner at NCSU (North Carolina State University), Tom McKendree at Hughes, and Todd Wipke at UCSC are underway.

Globus, Al↗

A linear decomposition method for large optimization problems. Blueprint for development

A method is proposed for decomposing large optimization problems encountered in the design of engineering systems such as an aircraft into a number of smaller subproblems. The decomposition is achieved by organizing the problem and the subordinated subproblems in a tree hierarchy and optimizing each subsystem separately. Coupling of the subproblems is accounted for by subsequent optimization of the entire system based on sensitivities of the suboptimization problem solutions at each level of the tree to variables of the next higher level. A formalization of the procedure suitable for computer implementation is developed and the state of readiness of the implementation building blocks is reviewed showing that the ingredients for the development are on the shelf. The decomposition method is also shown to be compatible with the natural human organization of the design process of engineering systems. The method is also examined with respect to the trends in computer hardware and software progress to point out that its efficiency can be amplified by network computing using parallel processors.

Sobieszczanski-Sobieski, J.↗

Software metrics: The quantitative impact of four factors on work rates experienced during software development

A model of a software development process is described. The software development process is seen to consist of a sequence of activities, such as 'program design' and 'module development' (or coding). A manpower estimate is made by multiplying code size by the rates (man months per thousand lines of code) for each of the activities relevant to the particular case of interest and summing up the results. The effect of four objectively determinable factors (organization, software product type, computer type, and code type) on productivity values for each of nine principal software development activities was assessed. Four factors were identified which account for 39% of the observed productivity variation.

Gaffney, J. E., Jr.↗

A real-time dynamic spacecraft simulator for the LANDSAT-D mission

A real time dynamic simulator for LANDSAT D was developed and has played an integral role in the development and validation of both the ground control system and of the on-board flight software. The simulator utilized an electronic replica of the spacecraft on-board computer and data handling hardware interfaced to a VAX 11/780 computer and simulation software. Key features of the simulator design are a modular software architecture tailored to the VAX/VMS real time capabilities, a microprocessor controlled interface between the VAX and the flight hardware replica, complete simulation of the spacecraft and NASA network communication links, and a flexible and powerful scenario structuring and operator control capability. The design goals and trade-offs, software, and hardware design are summarized. The application of the simulator to the validation of both the ground systems and on-board software is reviewed in detail.

Coffin, A. R.↗

Integrated design optimization research and development in an industrial environment

An overview is given of a design optimization project that is in progress at the GE Research and Development Center for the past few years. The objective of this project is to develop a methodology and a software system for design automation and optimization of structural/mechanical components and systems. The effort focuses on research and development issues and also on optimization applications that can be related to real-life industrial design problems. The overall technical approach is based on integration of numerical optimization techniques, finite element methods, CAE and software engineering, and artificial intelligence/expert systems (AI/ES) concepts. The role of each of these engineering technologies in the development of a unified design methodology is illustrated. A software system DESIGN-OPT has been developed for both size and shape optimization of structural components subjected to static as well as dynamic loadings. By integrating this software with an automatic mesh generator, a geometric modeler and an attribute specification computer code, a software module SHAPE-OPT has been developed for shape optimization. Details of these software packages together with their applications to some 2- and 3-dimensional design problems are described.

Kumar, V.↗

A software system for laser design and analysis

A laser-material database and laser-modeling software system for designing lasers for laser-based Light Detection And Ranging (LIDAR) systems are presented. The software system consists of three basic sections: the database, laser models, and interface software. The database contains the physical parameters of laser, optical, and nonlinear materials required by laser models. The models include efficiency calculations, electrooptical component models, resonator, amplifier, and oscillator models, and miscellaneous models. The interface software provides a user-friendly interface between the user and his personal data files, the database, and models. The structure of the software system is essentially in place, while future plans call for upgrading the computer hardware and software in order to support a multiuser multitask environment.

Cross, P. L.↗

The development of an engineering computer graphics laboratory

Hardware and software systems developed to further research and education in interactive computer graphics were described, as well as several of the ongoing application-oriented projects, educational graphics programs, and graduate research projects. The software system consists of a FORTRAN 4 subroutine package, in conjunction with a PDP 11/40 minicomputer as the primary computation processor and the Imlac PDS-1 as an intelligent display processor. The package comprises a comprehensive set of graphics routines for dynamic, structured two-dimensional display manipulation, and numerous routines to handle a variety of input devices at the Imlac.

Anderson, D. C.↗

Automated analysis of video data

A software/hardware system designed and developed to perform automated video imagery analysis is described. Major elements included in the analysis system are: (1) sampling oscilloscope; (2) programmable trigger unit; (3) central computer; and (4) software processing library. The function of the scope and trigger unit, in conjunction with the control computer, is to digitize the selected portion of the video image and store as amplitude and time data in computer memory. Evaluation of the video data, analogus to interpretation of a visual image, is accomplished by the processing software. It is indicated that this technique of video image analysis is applicable to a wide variety of nonaerospace applications involving video data and image analysis.

Hafner, D. J.↗

A toolbox and record for scientific models

Computational science presents a host of challenges for the field of knowledge-based software design. Scientific computation models are difficult to construct. Models constructed by one scientist are easily misapplied by other scientists to problems for which they are not well-suited. Finally, models constructed by one scientist are difficult for others to modify or extend to handle new types of problems. Construction of scientific models actually involves much more than the mechanics of building a single computational model. In the course of developing a model, a scientist will often test a candidate model against experimental data or against a priori expectations. Test results often lead to revisions of the model and a consequent need for additional testing. During a single model development session, a scientist typically examines a whole series of alternative models, each using different simplifying assumptions or modeling techniques. A useful scientific software design tool must support these aspects of the model development process as well. In particular, it should propose and carry out tests of candidate models. It should analyze test results and identify models and parts of models that must be changed. It should determine what types of changes can potentially cure a given negative test result. It should organize candidate models, test data, and test results into a coherent record of the development process. Finally, it should exploit the development record for two purposes: (1) automatically determining the applicability of a scientific model to a given problem; (2) supporting revision of a scientific model to handle a new type of problem. Existing knowledge-based software design tools must be extended in order to provide these facilities.

Ellman, Thomas↗

Hardware/Software Expansion of Display Terminal and CPU

IBM PC coupling used to expand capabilities of expensive specialpurpose system. IBM PC was interfaced to Tektronix CP1151 computer through teletype port of Tektronix 4010-1 computer display terminal. Electronic interface built to provide isolation, level shifting, and signal inversion between IBM PC RS-232 port and 4010-1 terminal teletype port. Modifications to 4010-1 terminal made to increase teletype rate from 110 to 9,600 baud. Software for both computers developed to give control of DPO system to IBM PC and provide data/program file exchange between two computers. Coupling demonstrates utilization of low-cost microcomputer hardware and software to expand capabilities of expensive special-purpose computer systems.

Adams, B. R.↗