DFTpy : An efficient and object-oriented platform for orbital-free DFT simulations
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Chemistry↗
SEARCH · Engineering Papers
Results for “Computer Programming and software”
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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Poetry in Programs: A Brief Examination of Software Aesthetics, Including Observations on the History of Programming Styles and Speculations on Post-object Programming
This viewgraph presentation provides samples of computer code which have characteristics of poetic verse, and addresses the theoretical underpinnings of artistic coding, as well as how computer language influences software style, and the possible style of future coding.
Filman, Robert E.↗
IPCS implications for future supersonic transport aircraft
The Integrated Propulsion Control System (IPCS) demonstrates control of an entire supersonic propulsion module - inlet, engine afterburner, and nozzle - with an HDC 601 digital computer. The program encompasses the design, build, qualification, and flight testing of control modes, software, and hardware. The flight test vehicle is an F-111E airplane. The L.H. inlet and engine will be operated under control of a digital computer mounted in the weapons bay. A general description and the current status of the IPCS program are given.
Billig, L. O.↗
SIERRA Multimechanics Module: Aria Thermal Theory Manual - Version 4.48
This document describes the theoretical foundation of thermal analysis in Sierra Mechanics. The SIERRA Multimechanics Module: Aria, henceforth referred to as Aria for brevity, was developed at Sandia National Laboratories under the ASC program, and approximates linear and nonlinear continuum models of heat transfer. Aria uses the SIERRA Framework, which provides data management services commonly required by computational mechanics software, and facilitates the development of coupled, multi-mechanics applications for massively parallel computers. The mathematical models in Aria are based heavily on those of COYOTE, a well-established thermal analysis program that was also developed at Sandia and its ASC code predecessor, Calore. Aria, Calore and COYOTE share a significant body of numerical methods, which are described in detail by Reddy and Gartling. Throughout this document, the terms software and implementation are syn onymous with the Aria thermal-fluid analysis computer program. Whether one uses Aria to perform heat transfer analysis, or in developing a new capability for the Aria application, this document provides the information needed understand the existing numerical algorithm implementations. Justification for the fundamental assumptions of heat transfer, nor derivation of the energy conservation equations are included in this document. For a more thorough theoretical background, one is referred to one of the many available textbooks, e.g. Another reference, which is freely available in downloadable electronic form, is Lienhard and Lienhard.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Applying optimization software libraries to engineering problems
Nonlinear programming, preliminary design problems, performance simulation problems trajectory optimization, flight computer optimization, and linear least squares problems are among the topics covered. The nonlinear programming applications encountered in a large aerospace company are a real challenge to those who provide mathematical software libraries and consultation services. Typical applications include preliminary design studies, data fitting and filtering, jet engine simulations, control system analysis, and trajectory optimization and optimal control. Problem sizes range from single-variable unconstrained minimization to constrained problems with highly nonlinear functions and hundreds of variables. Most of the applications can be posed as nonlinearly constrained minimization problems. Highly complex optimization problems with many variables were formulated in the early days of computing. At the time, many problems had to be reformulated or bypassed entirely, and solution methods often relied on problem-specific strategies. Problems with more than ten variables usually went unsolved.
Healy, M. J.↗
COSMIC monthly progress report
Activities of the Computer Software Management and Information Center (COSMIC) are summarized for the month of August, 1993. Tables showing the current inventory of programs available from COSMIC are presented and program processing and evaluation activities are discussed. Ten articles were prepared for publication in the NASA Tech Brief Journal. These articles (included in this report) describe the following software items: (1) MOM3D - A Method of Moments Code for Electromagnetic Scattering (UNIX Version); (2) EM-Animate - Computer Program for Displaying and Animating the Steady-State Time-Harmonic Electromagnetic Near Field and Surface-Current Solutions; (3) MOM3D - A Method of Moments Code for Electromagnetic Scattering (IBM PC Version); (4) M414 - MIL-STD-414 Variable Sampling Procedures Computer Program; (5) MEDOF - Minimum Euclidean Distance Optimal Filter; (6) CLIPS 6.0 - C Language Integrated Production System, Version 6.0 (Macintosh Version); (7) CLIPS 6.0 - C Language Integrated Production System, Version 6.0 (IBM PC Version); (8) CLIPS 6.0 - C Language Integrated Production System, Version 6.0 (UNIX Version); (9) CLIPS 6.0 - C Language Integrated Production System, Version 6.0 (DEC VAX VMS Version); and (10) TFSSRA - Thick Frequency Selective Surface with Rectangular Apertures. Activities in the areas of marketing, customer service, benefits identification, maintenance and support, and dissemination are also described along with a budget summary.
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Method Of Predicting Size Of Software Under Development
Method of estimating size and complexity of large computer program under development based on metric called "function mass." Simplification of Demarco's "function bang" metric. Size of completed program usually expressed in terms of number of lines of code (SLOC), shown in previous research to be highly correlated with amount of development effort and therefore important predictor of development cost. Proposed method of estimating ultimate size of program is intermediate product of continuing research on estimation of size and structured analysis of developmental software.
Hihn, Jairus M.↗
A Hybrid FPGA/Tilera Compute Element for Autonomous Hazard Detection and Navigation
To increase safety for future missions landing on other planetary or lunar bodies, the Autonomous Landing and Hazard Avoidance Technology (ALHAT) program is developing an integrated sensor for autonomous surface analysis and hazard determination. The ALHAT Hazard Detection System (HDS) consists of a Flash LIDAR for measuring the topography of the landing site, a gimbal to scan across the terrain, and an Inertial Measurement Unit (IMU), along with terrain analysis algorithms to identify the landing site and the local hazards. An FPGA and Manycore processor system was developed to interface all the devices in the HDS, to provide high-resolution timing to accurately measure system state, and to run the surface analysis algorithms quickly and efficiently. In this paper, we will describe how we integrated COTS components such as an FPGA evaluation board, a TILExpress64, and multi-threaded/multi-core aware software to build the HDS Compute Element (HDSCE). The ALHAT program is also working with the NASA Morpheus Project and has integrated the HDS as a sensor on the Morpheus Lander. This paper will also describe how the HDS is integrated with the Morpheus lander and the results of the initial test flights with the HDS installed. We will also describe future improvements to the HDSCE.
Multicore↗
A hybrid FPGA/Tilera compute element for autonomous hazard detection and navigation
To increase safety for future missions landing on other planetary or lunar bodies, the Autonomous Landing and Hazard Avoidance Technology (ALHAT) program is developing an integrated sensor for autonomous surface analysis and hazard determination. The ALHAT Hazard Detection System (HDS) consists of a Flash LIDAR for measuring the topography of the landing site, a gimbal to scan across the terrain, and an Inertial Measurement Unit (IMU), along with terrain analysis algorithms to identify the landing site and the local hazards. An FPGA and Manycore processor system was developed to interface all the devices in the HDS, to provide high-resolution timing to accurately measure system state, and to run the surface analysis algorithms quickly and efficiently. In this paper, we will describe how we integrated COTS components such as an FPGA evaluation board, a TILExpress64, and multi-threaded/multi-core aware software to build the HDS Compute Element (HDSCE). The ALHAT program is also working with the NASA Morpheus Project and has integrated the HDS as a sensor on the Morpheus Lander. This paper will also describe how the HDS is integrated with the Morpheus lander and the results of the initial test flights with the HDS installed. We will also describe future improvements to the HDSCE.
Trawny, Nikolas↗
Software for Sharing and Management of Information
DIAMS is a set of computer programs that implements a system of collaborative agents that serve multiple, geographically distributed users communicating via the Internet. DIAMS provides a user interface as a Java applet that runs on each user s computer and that works within the context of the user s Internet-browser software. DIAMS helps all its users to manage, gain access to, share, and exchange information in databases that they maintain on their computers. One of the DIAMS agents is a personal agent that helps its owner find information most relevant to current needs. It provides software tools and utilities for users to manage their information repositories with dynamic organization and virtual views. Capabilities for generating flexible hierarchical displays are integrated with capabilities for indexed- query searching to support effective access to information. Automatic indexing methods are employed to support users queries and communication between agents. The catalog of a repository is kept in object-oriented storage to facilitate sharing of information. Collaboration between users is aided by matchmaker agents and by automated exchange of information. The matchmaker agents are designed to establish connections between users who have similar interests and expertise.
Chen, James R.↗
High Performance Computing - Power Application Programming Interface Specification Version 2.0.
Measuring and controlling the power and energy consumption of high performance computing systems by various components in the software stack is an active research area. Implementations in lower level software layers are beginning to emerge in some production systems, which is very welcome. To be most effective, a portable interface to measurement and control features would significantly facilitate participation by all levels of the software stack. We present a proposal for a standard power Application Programming Interface (API) that endeavors to cover the entire software space, from generic hardware interfaces to the input from the computer facility manager.
97 MATHEMATICS AND COMPUTING↗
Computer Technology for Industry
In this age of the computer, more and more business firms are automating their operations for increased efficiency in a great variety of jobs, from simple accounting to managing inventories, from precise machining to analyzing complex structures. In the interest of national productivity, NASA is providing assistance both to longtime computer users and newcomers to automated operations. Through a special technology utilization service, NASA saves industry time and money by making available already developed computer programs which have secondary utility. A computer program is essentially a set of instructions which tells the computer how to produce desired information or effect by drawing upon its stored input. Developing a new program from scratch can be costly and time-consuming. Very often, however, a program developed for one purpose can readily be adapted to a totally different application. To help industry take advantage of existing computer technology, NASA operates the Computer Software Management and Information Center (COSMIC)(registered TradeMark),located at the University of Georgia. COSMIC maintains a large library of computer programs developed for NASA, the Department of Defense, the Department of Energy and other technology-generating agencies of the government. The Center gets a continual flow of software packages, screens them for adaptability to private sector usage, stores them and informs potential customers of their availability.
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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.↗
Distributed computer system enhances productivity for SRB joint optimization
The Programming System for Structural Synthesis software package, which couples structural analysis and optimization, has been distributed over a network of work stations for use in Space Shuttle Solid Rocket Booster joint redesign optimization. Finite difference computing techniques were applied to the optimization gradients in parallel execution, allowing several work stations to simultaneously contribute to the problem's solution. An optimal joint shape was obtained which achieves minimum weight while keeping the gap between joints well closed and limiting structural stresses. The optimization cycle was reduced from two hours to one-half hour.
Rogers, James L., Jr.↗
Computational structural mechanics for engine structures
The computational structural mechanics (CSM) program at Lewis encompasses: (1) fundamental aspects for formulating and solving structural mechanics problems, and (2) development of integrated software systems to computationally simulate the performance/durability/life of engine structures. It is structured to mainly supplement, complement, and whenever possible replace, costly experimental efforts which are unavoidable during engineering research and development programs. Specific objectives include: investigate unique advantages of parallel and multiprocesses for: reformulating/solving structural mechanics and formulating/solving multidisciplinary mechanics and develop integrated structural system computational simulators for: predicting structural performances, evaluating newly developed methods, and for identifying and prioritizing improved/missing methods needed. Herein the CSM program is summarized with emphasis on the Engine Structures Computational Simulator (ESCS). Typical results obtained using ESCS are described to illustrate its versatility.
Chamis, C. C.↗
Dynamic modeling and simulation of pressure swing adsorption processes using toPSAil
Pressure swing adsorption (PSA) has attracted significant recent interest for chemical process intensification due to its potential for high energy efficiency and amenability to small, modular designs. However, the lack of simulation tools that are readily available, transparent, and trusted, has been identified as a serious impediment to widespread adoption of PSA, as well as to further research on PSA modeling, numerical solution, optimization, and control. This paper presents a complete framework for dynamic modeling and simulation of PSA processes and its implementation in an open-source simulator called toPSAil. Further, the presentation is tutorial and includes many modeling and implementation details often overlooked in existing literature. Novel methods are presented for handling flow reversals and implementing various pressure–flow relationships, along with controlled boundary conditions. Finally, the code contains several innovations designed to improve efficiency and reduce the extensive trial-and-error tuning often required to produce a working PSA cycle.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
The TENNLab Exploratory Neuromorphic Computing Framework
Spiking, neuromorphic computing systems are in a period of active exploration by the computing community. While they feature computational expressiveness beyond both von Neumann computing models and feed-forward neural networks, they are also challenging to design and program. The TENNLab exploratory neuromorphic computing framework is a software infrastructure, soon to be open-source, whose goal is to enable potential users of spiking, neuromorphic computing systems to develop applications and evaluate computing architectures, and for architecture researchers to develop and evaluate their architectures with a variety of applications. In this letter, we present the software architecture of the TENNLab framework.
97 MATHEMATICS AND COMPUTING↗
Computational Fluid Dynamic Modeling of Dry Cask Simulator with Crosswind
The purpose of this study is to create a STAR-CCM+ model of a Belowground Vertical Dry Cask Simulator (BVDCS) at Sandia National Laboratories (SNL) and validate the model with SNL’s experimental results. The BVDCS consists of a single boiling water reactor assembly fitted with electric heaters encompassed by a containment vessel and shell to represent a belowground spent nuclear fuel (SNF) dry storage system. Blowers are located near the inlet and outlet of the BVDCS to simulate crosswind conditions. In addition to the experimental results, the STAR-CCM+ model developed for this study is compared with a previous computational fluid dynamics (CFD) model in a different software program, which is used as a software-to-software benchmark. The experimental results provide a dataset to compare the STAR-CCM+ model results for a variety of different conditions. The main objective is to validate and improve STAR-CCM+ CFD models for spent nuclear fuel storage systems with explicitly modeled external environments and “wind driven” crossflows. These CFD models aide in the study of external particle deposition in spent nuclear fuel storage systems, which is important to predicting the significance of chloride induced stress corrosion cracking (CISCC). In addition to experimental comparison, a sensitivity analysis study is performed using the STAR-CCM+ model. The sensitivity analysis provides a quantitative assessment of the sensitivity of various parameters. This helps provide information on various parameters that are of particular importance to constructing a model representative of real life systems. The STAR-CCM+ model compared well to the experimental results showing similar responses to changes in cross wind flow, and a number of parameters are identified for model improvement.
Jensen, Ben J.↗