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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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At least 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
DOE OSTI2019

Can I/O Variability Be Reduced on QoS-Less HPC Storage Systems?

For a production high-performance computing (HPC) system, where storage devices are shared between multiple applications and managed in a best effort manner, I/O contention is often a major problem. In this paper, we propose a balanced messaging-based re-routing in conjunction with throttling at the middleware level. This work tackles two key challenges that have not been fully resolved in the past: whether I/O variability can be reduced on a QoS-less HPC storage system, and how to design a runtime scheduling system that can scale up to a large amount of cores. The proposed scheme uses a two-level messaging system to re-route I/O requests to a less congested storage location so that write performance is improved, while limiting the impact on read by throttling re-routing. An analytical model is derived to guide the setup of optimal throttling factor. We thoroughly analyze the virtual messaging layer overhead and explore whether the in-transit buffering is effective in managing I/O variability. Contrary to the intuition, in-transit buffer cannot completely solve the problem. It can reduce the absolute variability but not the relative variability. The proposed scheme is verified against a synthetic benchmark as well as being used by production applications.

Huang, Dan↗
NASA NTRS1992

Engine monitoring display study

The current study is part of a larger NASA effort to develop displays for an engine-monitoring system to enable the crew to monitor engine parameter trends more effectively. The objective was to evaluate the operational utility of adding three types of information to the basic Boeing Engine Indicating and Crew Alerting System (EICAS) display formats: alphanumeric alerting messages for engine parameters whose values exceed caution or warning limits; alphanumeric messages to monitor engine parameters that deviate from expected values; and a graphic depiction of the range of expected values for current conditions. Ten training and line pilots each flew 15 simulated flight scenarios with five variants of the basic EICAS format; these variants included different combinations of the added information. The pilots detected engine problems more quickly when engine alerting messages were included in the display; adding a graphic depiction of the range of expected values did not affect detection speed. The pilots rated both types of alphanumeric messages (alert and monitor parameter) as more useful and easier to interpret than the graphic depiction. Integrating engine parameter messages into the EICAS alerting system appears to be both useful and preferred.

Hornsby, Mary E.↗
NASA NTRS1978

Preventing radio-paging system tieup

Time-delay relay limits message time of emergency radio-paging system, thereby preventing inadvertent tieup. Relay is connected with telephone circuit and permits adjustable message time between 30 and 55 seconds. After that time interval, relay opens, making line free for another paging regardless of what previous caller did with his telephone.

Jasmin, J. P.↗
DOE OSTI2014

Broadcasting a message in a parallel computer

Methods, systems, and products are disclosed for broadcasting a message in a parallel computer that includes: transmitting, by the logical root to all of the nodes directly connected to the logical root, a message; and for each node except the logical root: receiving the message; if that node is the physical root, then transmitting the message to all of the child nodes except the child node from which the message was received; if that node received the message from a parent node and if that node is not a leaf node, then transmitting the message to all of the child nodes; and if that node received the message from a child node and if that node is not the physical root, then transmitting the message to all of the child nodes except the child node from which the message was received and transmitting the message to the parent node.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1989

Run-time scheduling and execution of loops on message passing machines

Sparse system solvers and general purpose codes for solving partial differential equations are examples of the many types of problems whose irregularity can result in poor performance on distributed memory machines. Often, the data structures used in these problems are very flexible. Crucial details concerning loop dependences are encoded in these structures rather than being explicitly represented in the program. Good methods for parallelizing and partitioning these types of problems require assignment of computations in rather arbitrary ways. Naive implementations of programs on distributed memory machines requiring general loop partitions can be extremely inefficient. Instead, the scheduling mechanism needs to capture the data reference patterns of the loops in order to partition the problem. First, the indices assigned to each processor must be locally numbered. Next, it is necessary to precompute what information is needed by each processor at various points in the computation. The precomputed information is then used to generate an execution template designed to carry out the computation, communication, and partitioning of data, in an optimized manner. The design is presented for a general preprocessor and schedule executer, the structures of which do not vary, even though the details of the computation and of the type of information are problem dependent.

Crowley, Kay↗
NASA NTRS1990

Run-time scheduling and execution of loops on message passing machines

Sparse system solvers and general purpose codes for solving partial differential equations are examples of the many types of problems whose irregularity can result in poor performance on distributed memory machines. Often, the data structures used in these problems are very flexible. Crucial details concerning loop dependences are encoded in these structures rather than being explicitly represented in the program. Good methods for parallelizing and partitioning these types of problems require assignment of computations in rather arbitrary ways. Naive implementations of programs on distributed memory machines requiring general loop partitions can be extremely inefficient. Instead, the scheduling mechanism needs to capture the data reference patterns of the loops in order to partition the problem. First, the indices assigned to each processor must be locally numbered. Next, it is necessary to precompute what information is needed by each processor at various points in the computation. The precomputed information is then used to generate an execution template designed to carry out the computation, communication, and partitioning of data, in an optimized manner. The design is presented for a general preprocessor and schedule executer, the structures of which do not vary, even though the details of the computation and of the type of information are problem dependent.

Saltz, Joel↗
NASA NTRS1995

An object-oriented, technology-adaptive information model

The primary objective was to develop a computer information system for effectively presenting NASA's technologies to American industries, for appropriate commercialization. To this end a comprehensive information management model, applicable to a wide variety of situations, and immune to computer software/hardware technological gyrations, was developed. The model consists of four main elements: a DATA_STORE, a data PRODUCER/UPDATER_CLIENT and a data PRESENTATION_CLIENT, anchored to a central object-oriented SERVER engine. This server engine facilitates exchanges among the other model elements and safeguards the integrity of the DATA_STORE element. It is designed to support new technologies, as they become available, such as Object Linking and Embedding (OLE), on-demand audio-video data streaming with compression (such as is required for video conferencing), Worldwide Web (WWW) and other information services and browsing, fax-back data requests, presentation of information on CD-ROM, and regular in-house database management, regardless of the data model in place. The four components of this information model interact through a system of intelligent message agents which are customized to specific information exchange needs. This model is at the leading edge of modern information management models. It is independent of technological changes and can be implemented in a variety of ways to meet the specific needs of any communications situation. This summer a partial implementation of the model has been achieved. The structure of the DATA_STORE has been fully specified and successfully tested using Microsoft's FoxPro 2.6 database management system. Data PRODUCER/UPDATER and PRESENTATION architectures have been developed and also successfully implemented in FoxPro; and work has started on a full implementation of the SERVER engine. The model has also been successfully applied to a CD-ROM presentation of NASA's technologies in support of Langley Research Center's TAG efforts.

Anyiwo, Joshua C.↗
NASA NTRS1989

The Father Christmas worm

Given here is an overview analysis of the Father Christmas Worm, a computer worm that was released onto the DECnet Internet three days before Christmas 1988. The purpose behind the worm was to send an electronic mail message to all users on the computer system running the worm. The message was a Christmas greeting and was signed 'Father Christmas'. From the investigation, it was determined that the worm was released from a computer (node number 20597::) at a university in Switzerland. The worm was designed to travel quickly. Estimates are that it was copied to over 6,000 computer nodes. However, it was believed to have executed on only a fraction of those computers. Within ten minutes after it was released, the worm was detected at the Space Physics Analysis Network (SPAN), NASA's largest space and Earth science network. Once the source program was captured, a procedural cure, using the existing functionality of the computer operating systems, was quickly devised and distributed. A combination of existing computer security measures, the quick and accurate procedures devised to stop copies of the worm from executing, and the network itself, were used to rapidly provide the cure. These were the main reasons why the worm executed on such a small percentage of nodes. This overview of the analysis of the events concerning the worm is based on an investigation made by the SPAN Security Team and provides some insight into future security measures that will be taken to handle computer worms and viruses that may hit similar networks.

Green, James L.↗
NASA NTRS1989

Reliable broadcast protocols

A number of broadcast protocols that are reliable subject to a variety of ordering and delivery guarantees are considered. Developing applications that are distributed over a number of sites and/or must tolerate the failures of some of them becomes a considerably simpler task when such protocols are available for communication. Without such protocols the kinds of distributed applications that can reasonably be built will have a very limited scope. As the trend towards distribution and decentralization continues, it will not be surprising if reliable broadcast protocols have the same role in distributed operating systems of the future that message passing mechanisms have in the operating systems of today. On the other hand, the problems of engineering such a system remain large. For example, deciding which protocol is the most appropriate to use in a certain situation or how to balance the latency-communication-storage costs is not an easy question.

Joseph, T. A.↗
NASA NTRS2018

Design and Development of Responder: a Notification-Acknowledgment Android OS Phone Application

This paper discusses the design and development of the Android phone application Responder and how it assists Flight Operation Team (FOT) members in handling alerts from a Short Message Service (SMS) text message and email based notification system. The FOT needed a simplified and more powerful tool for receiving, storing, and acknowledging notifications sent from the ground systems automated notification software called Attention! (Registered Trademark). The previous system was to rely on a text message application that comes on a phone. This way was slow, inefficient, and did a poor job of keeping FOT members informed on the state of a situation when multiple notifications are being sent out by Attention! (Registered Trademark). Responder is designed to provide easier viewing and acknowledging of multiple messages. It gives the user a quick look at all recently received messages in an organized and clean manner that prevents notifications from being lost during a large burst of messages. It makes it easier to find and review old messages received and Responder was designed to give the user more flexibility in setting up how and what alerts will notify them when they are received by the phone. Since the implementation of Responder the FOT members are more informed and are able to focus more on problem solving the reason a notification was received then trying to keep up with sending cumbersome acknowledgements over text message or email. Responder is only able to receive and send SMS text messages but by using email to text services provided by the cellular carrier it is able to send and receive emails.

notification↗
DOE OSTI2024

A Large-Scale Analysis to Optimize the Control and V2V Communication Protocols for CDA Agreement-Seeking Cooperation

Cooperative driving automation (CDA) Class C, agreement-seeking cooperation, is an innovative and practical solution that can promote cooperation among general passenger vehicles on the road. However, more comprehensive studies are needed before establishing the standard protocols of agreement-seeking cooperation, such as communication frequency and the duration of cooperation. Here, this article presents an initiative study on the impacts of communication capabilities on agreement-seeking cooperation. Through a large-scale analysis by regulating vehicle-to-vehicle (V2V) communication metrics, this work suggests desirable system parameters that can maximize the benefits of cooperation and ensure reliable operability while avoiding exhaustive communication loads. As the first step, an example agreement-seeking cooperation system is created for a car-following scenario, including decision-making and control algorithms for autonomous vehicles. Then, software-in-the-loop tests explore the performance of the developed system as it encounters various communication risks, such as latency and message packet drops. The system performance metrics are evaluated from various angles, including the time consumed for the agreement-seeking process, cooperation ratio, and the ratio of faulty cooperation. Energy saving from the cooperation is assessed by using simulation software that can run multiple high-fidelity vehicle models simultaneously. Based on the analyses, this article suggests the V2V communication requirements for the reliable operation of CDA agreement-seeking, which can be referred to when developing the standard protocols of agreement-seeking cooperation.

42 ENGINEERING↗
DOE OSTI2026

SDN-Based Dynamic Cybersecurity Framework of IEC-61850 Communications in Smart Grid

In recent years, critical infrastructure and power grids have experienced a series of cyber-attacks, leading to temporary, widespread blackouts of considerable magnitude. Since most substations are unmanned and have limited physical security protection, cyber breaches into power grid substations present a risk. Nowadays, the susceptibility of SDN architecture to cyber-attacks has exhibited a notable increase in recent years, as indicated by research findings. This suggests a growing concern regarding the potential for cybersecurity breaches within the SDN framework. In this paper, we propose a hybrid intrusion detection system (IDS)-integrated SDN architecture for detecting and preventing the injection of malicious IEC 61850-based generic object-oriented system event (GOOSE) messages in a digital substation. Additionally, this program locates the fault’s location and, as a form of mitigation, disables a certain port. Furthermore, implementation examples are demonstrated and verified using a hardware-in-the-loop (HIL) testbed that mimics the functioning of a digital substation.

Liu, Chen-Ching [Virginia Tech] (ORCID:00000002894↗
DOE OSTI2026

SDN-Based Smart Cyber Switching (SCS) for Cyber Restoration of a Digital Substation

In recent years, critical infrastructure and power grids have increasingly been targets of cyber-attacks, causing widespread and extended blackouts. Digital substations are particularly vulnerable to such cyber incursions, jeopardizing grid stability. This paper addresses these risks by proposing a cybersecurity framework that leverages software-defined networking (SDN) to bolster the resilience of substations based on the IEC- 61850 standard. The research introduces a strategy involving smart cyber switching (SCS) for mitigation and concurrent intelligent electronic device (CIED) for restoration, ensuring ongoing operational integrity and cybersecurity within a substation. The SCS framework improves the physical network’s behavior (i.e., leveraging commercial SDN capabilities) by incorporating an adaptive port controller (APC) module for dynamic port management and an intrusion detection system (IDS) to detect and counteract malicious IEC-61850-based sampled value (SV) and generic object-oriented system event (GOOSE) messages within the substation’s communication network. The framework’s effectiveness is validated through comprehensive simulations and a hardware-in-the-loop (HIL) testbed, demonstrating its ability to sustain substation operations during cyber-attacks and significantly improve the overall resilience of the power grid.

Liu, Chen-Ching (ORCID:0000000289417958)↗
NASA NTRS1976

NASA study of an automated Pilot Advisory System

A Pilot Advisory System (PAS) concept for high-density uncontrolled airports is discussed where the general aviation pilots will be provided with automatic audio voice airport and air traffic advisories within two minute intervals and with mid-air collision warnings whenever such situations arise. Free of manual inputs, the PAS includes the options of fixed-base operator runway select, automatic restart and self-test, and remote inquiry of system status and messages.

Parker, L. C.↗
NASA NTRS1981

The SMART MIL-STD-1553 bus adapter hardware manual

The SMART Multiplexer Interface Adapter, (SMIA) a complete system interface for message structure of the MIL-STD-1553, is described. It provides buffering and storage for transmitted and received data and handles all the necessary handshaking to interface between parallel 8-bit data bus and a MIL-STD serial bit stream. The bus adapter is configured as either a bus controller of a remote terminal interface. It is coupled directly to the multiplex bus, or stub coupled through an additional isolation transformer located at the connection point. Fault isolation resistors provide short circuit protection.

Ton, T. T.↗
NASA NTRS1981

The estimation of convective precipitation from GOES imagery with the Griffith/Woodley technique

Improved rainfall monitoring using satellite and conventional data are described. A method was developed to: (1) provide rainfall evaluations more uniform, accurate and complete than can be derived from satellite or conventional data alone; (2) serve current operational environmental program in countries with special needs for improved rainfall data; (3) invoke either polar orbiting and/or geostationary imagery as the satellite inputs; (4) utilize global telecommunication system (GTS) SYNOP messages as the basic conventional data inputs; (5) be applicable to any and all types of weather situations in the operational areas; (6) be undemanding in hardware and software so as to be an option available for use even by nations or agencies with very limited financial resources.

Griffith, C. G.↗
NASA NTRS1988

Spectral element methods: Algorithms and architectures

Spectral element methods are high-order weighted residual techniques for partial differential equations that combine the geometric flexibility of finite element methods with the rapid convergence of spectral techniques. Spectral element methods are described for the simulation of incompressible fluid flows, with special emphasis on implementation of spectral element techniques on medium-grained parallel processors. Two parallel architectures are considered: the first, a commercially available message-passing hypercube system; the second, a developmental reconfigurable architecture based on Geometry-Defining Processors. High parallel efficiency is obtained in hypercube spectral element computations, indicating that load balancing and communication issues can be successfully addressed by a high-order technique/medium-grained processor algorithm-architecture coupling.

Fischer, Paul↗
NASA NTRS1988

Spectral element methods - Algorithms and architectures

Spectral element methods are high-order weighted residual techniques for partial differential equations that combine the geometric flexibility of finite element methods with the rapid convergence of spectral techniques. Spectral element methods are described for the simulation of incompressible fluid flows, with special emphasis on implementation of spectral element techniques on medium-grained parallel processors. Two parallel architectures are considered; the first, a commercially available message-passing hypercube system; the second, a developmental reconfigurable architecture based on Geometry-Defining Processors. High parallel efficiency is obtained in hypercube spectral element computations, indicating that load balancing and communication issues can be successfully addressed by a high-order technique/medium-grained processor algorithm-architecture coupling.

Fischer, Paul↗