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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 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

A Case Study of LLVM-Based Analysis for Optimizing SIMD Code Generation

This paper presents a methodology for using LLVM-based tools to tune the DCA++ (dynamical cluster approximation) application that targets the new ARM A64FX processor. The goal is to describe the changes required for the new architecture and generate efficient single instruction/multiple data (SIMD) instructions that target the new Scalable Vector Extension instruction set. During manual tuning, the authors used the LLVM tools to improve code parallelization by using OpenMP SIMD, refactored the code and applied transformation that enabled SIMD optimizations, and ensured that the correct libraries were used to achieve optimal performance. By applying these code changes, code speed was increased by 1.98× and 78 GFlops were achieved on the A64FX processor. The authors aim to automatize parts of the efforts in the OpenMP Advisor tool, which is built on top of existing and newly introduced LLVM tooling.

Huber, Joseph↗
DOE OSTI2021

Method and system for determining a geographical location of an unmanned aerial vehicle flown in proximity to a power grid

A method for determining geolocation of a UAV near a power grid includes detecting, via a transceiver, a carrier signal transmitted from a first grid node to identify the node's fixed geolocation. A response signal may be transmitted from a second grid node in response to the carrier signal to identify a fixed geolocation of the second grid node, or the UAV may process the carrier signal. A processor determines time-of-flight of the carrier signal, e.g., using the response signal, and derives the UAV's geolocation using the time-of-flight. Determining time-of-flight may include referencing a lookup table indexed by time-of-arrival at the transceiver of the modulated carrier and response signals. A timestamp may indicate time-of-transmission of the carrier and response signals, respectively. Deriving geolocation may include subtracting time-of-transmission of the response signal from that of the carrier signal. A system includes the processor and transceiver.

Moore, Andrew J.↗
DOE OSTI2021

High speed two-dimensional imaging with an analog interface

A quantitative pulse count (event detection) algorithm with linearity to high count rates is accomplished by combining a high-speed, high frame rate camera with simple logic code run on a massively parallel processor such as a GPU. The parallel processor elements examine frames from the camera pixel by pixel to find and tag events or count pulses. The tagged events are combined to form a combined quantitative event image.

Waugh, Justin↗
DOE OSTI2021

System and method for inspecting parts using dynamic response function

A system and method for the non-destructive testing of additively manufactured parts. An input mechanism excites with an excitation force (e.g., a vibration) an additive manufacturing build structure, which includes a part on a build platform, to induce a dynamic response in the part. An output mechanism (e.g., a non-contact transducer) senses the induced dynamic response in the part. A processor determines and examines the relationship between the response and excitation to identify an indication of a defect in the part, and communicates an alert if the indication is identified. The processor may compare the phase, magnitude, coherence, or time delay of the relationship to a reference relationship and/or may compare the modal frequency or the modal damping to a reference to identify a deviation greater than a pre-established threshold.

Hartwig, Troy Juan↗
DOE OSTI2022

Improving the Performance of DGEMM with MoA and Cache-Blocking: Preprint

The goal of this paper is to demonstrate performance enhancements of the high performance dense linear algebra matrix-matrix multiply DGEMM kernel, widely implemented by vendors in the basic linear algebra subroutine BLAS library. The mathematics of arrays (MoA) paradigm due to Mullin (1988) results in contiguous memory accesses in combination with Church-Rosser complete language constructs optimized for target processor architectures [3]. Our performance studies demonstrate that the MoA implementation of DGEMM combined with optimal cache-blocking strategies results in at least a 25% performance gain on both Intel Xeon Skylake and IBM Power-9 processors over the vendor supplied Intel MKL and IBM ESSL basic linear algebra libraries. Results are presented for the NREL Eagle and ORNL Summit supercomputers.

cache-blocking↗
DOE OSTI2021

Data compression system using base values and methods thereof

In some embodiments, a memory controller in a processor includes a base value cache, a compressor, and a metadata cache. The compressor is coupled to the base value cache and the metadata cache. The compressor compresses a data block using at least a base value and delta values. The compressor determines whether the size of the data block exceeds a data block threshold value. Based on the determination of whether the size of the compressed data block generated by the compressor exceeds the data block threshold value, the memory controller transfers only a set of the compressed delta values to memory for storage. A decompressor located in the lower level cache of the processor decompresses the compressed data block using the base value stored in the base value cache, metadata stored in the metadata cache and the delta values stored in memory.

Seyedzadehdelcheh, SeyedMohammad↗
DOE OSTI2022

Failure Mechanism Traceability and Application in Human System Interface of Nuclear Power Plants using RESHA

In recent years, there has been considerable effort to modernize existing and new nuclear power plants with digital instrumentation and control systems (DI&C). However, there has also been considerable concern both by industry and regulatory bodies for the risk and consequence analysis of these systems. Of particular concern are digital common cause failures (CCFs) specifically related to software defects. These “misbehaviors” by the software can occur in both the control and monitoring of a system. While many new methods have been proposed to identify potential software failure modes, such as Systems-theoretic Process Analysis (STPA), Hazard and Consequence Analysis for Digital Systems (HAZCADS), etc., these methods are focused primarily on the control action pathway of a system. In contrast, the information feedback pathway lacks unsafe control actions (UCAs), which are typically related to software basic events; thus, assessment of software basic events in such systems is unclear. In this work, we present the idea of intermediate processors and unsafe information flow (UIF) to help safety analysts trace failure mechanisms in the feedback pathway and how they can be integrated into a fault tree for improved assessment capability. The concepts presented are demonstrated in two comprehensive case studies, a smart sensor integrated platform for unmanned autonomous vehicles and another on a representative advanced human system interface (HSI) for safety critical plant monitoring. The qualitative software basic events are identified, and a fault tree analysis is conducted based on a modified Redundancy-guided Systems-theoretic Hazard Analysis (RESHA) methodology. The case studies demonstrate the use of UIF and intermediate processors in the fault tree to improve traceability of software failures in highly complex digital instrumentation feedback. The improved method can also clarify fault tree construction when multiple component dependencies are present in the system.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Failure Mechanism Traceability and Application in Human System Interface of Nuclear Power Plants using RESHA

In recent years, there has been considerable effort to modernize existing and new nuclear power plants with digital instrumentation and control systems (DI&C). However, there has also been considerable concern both by industry and regulatory bodies for the risk and consequence analysis of these systems. Of particular concern are digital common cause failures (CCFs) specifically related to software defects. These “misbehaviors” by the software can occur in both the control and monitoring of a system. While many new methods have been proposed to identify potential software failure modes, such as Systems-theoretic Process Analysis (STPA), Hazard and Consequence Analysis for Digital Systems (HAZCADS), etc., these methods are focused primarily on the control action pathway of a system. In contrast, the information feedback pathway lacks unsafe control actions (UCAs), which are typically related to software basic events; thus, assessment of software basic events in such systems is unclear. In this work, we present the idea of intermediate processors and unsafe information flow (UIF) to help safety analysts trace failure mechanisms in the feedback pathway and how they can be integrated into a fault tree for improved assessment capability. The concepts presented are demonstrated in two comprehensive case studies, a smart sensor integrated platform for unmanned autonomous vehicles and another on a representative advanced human system interface (HSI) for safety critical plant monitoring. The qualitative software basic events are identified, and a fault tree analysis is conducted based on a modified Redundancy-guided Systems-theoretic Hazard Analysis (RESHA) methodology. The case studies demonstrate the use of UIF and intermediate processors in the fault tree to improve traceability of software failures in highly complex digital instrumentation feedback. The improved method can also clarify fault tree construction when multiple component dependencies are present in the system.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2022

Communication systems and methods

A communication system is provided that include one or more processors that are configured to instruct computing devices that communicate messages with each other via a time-sensitive network to securely exchange the messages using secret information, ad direct the computing devices to exchange the secret information via a dedicated quantum channel in the time-sensitive network. The one or more processors are also configured to determine a quantum channel synchronization time associated with the secret information exchanged via the dedicated quantum channel, and modify a local classical oscillator based on the quantum channel synchronization time, the local classical oscillator configured to provide a current time.

Bush, Stephen Francis↗
DOE OSTI2022

Coordinated net-load management

A management device includes at least one processor communicatively coupled to at least one energy resource controller controlling at least one energy resource and to at least one deferrable load controller controlling power to at least one deferrable load. The is configured to receive an indication, determined based on a frequency value of an electrical network and a nominal frequency value, that a frequency anomaly event has occurred. Responsive to receiving the indication that the frequency anomaly event has occurred, the processor is also configured to determine, for at least one of the energy resource and the deferrable load, based on the frequency value, the nominal frequency value, and a power value of the electrical network, a respective power command, and cause at least one of the at least one energy resource and the at least one deferrable load to modify operation based on the respective power command.

Lundstrom, Blake Richard↗
DOE OSTI2022

System, method, and computer program for creating an internal conforming structure

A system for creating an internal formation of a tubular structure having an inner surface via additive manufacturing. The system broadly includes a computer modeling system and an additive manufacturing system. The computer modeling system may include a processor for generating a lattice cellular component via computer-aided design software according to inputs received from a user. The processor may also generate an internal formation lattice structure based on the lattice cellular component and modify the lattice structure to follow and/or conform to the curvature of the inner surface of the outer wall of the tubular structure. The additive manufacturing system may be configured to produce the lattice structure and the tubular structure via additive manufacturing material deposited layer by layer according to the lattice structure.

42 ENGINEERING↗
DOE OSTI2022

GPU cache management based on locality type detection

Wavefront loading in a processor is managed and includes monitoring a selected wavefront of a set of wavefronts. Reuse of memory access requests for the selected wavefront is counted. A cache hit rate in one or more caches of the processor is determined based on the counted reuse. Based on the cache hit rate, subsequent memory requests of other wavefronts of the set of wavefronts are modified by including a type of reuse of cache lines in requests to the caches. In the caches, storage of data in the caches is based on the type of reuse indicated by the subsequent memory access requests. Reused cache lines are protected by preventing cache line contents from being replaced by another cache line for a duration of processing the set of wavefronts. Caches are bypassed when streaming access requests are made.

Zhang, Xianwei↗
DOE OSTI2022

Portable aircraft controller devices and systems

A portable computerized device for an aircraft control system includes an input system for inputting commands, a device display for displaying information on the computerized device, a processor, a wireless communication module, and a non-transitory computer readable medium comprising computer executable instructions, the computer executable instructions configured to cause the processor to perform a method. The method can include detecting whether the portable computerized device is in a cockpit state such that the portable computerized device is in and/or docked to an aircraft cockpit or if the portable computerized device is in a remote state such that the portable computerized device is not in an aircraft cockpit or is not docked to an aircraft cockpit. If the portable computerized device is determined to be in a remote state, the method includes operating the remote device in a remote mode. If the portable computerized device is determined to be in a cockpit state, the method includes operating the device in a local mode.

Sahay, Prateek↗
DOE OSTI2022

System and method for ultra-high-resolution ranging using RFID

A radio-frequency method for range finding includes modulating a reference signal having an intermediate frequency to a downlink signal having a carrier frequency using a clock signal. The downlink signal is transmitted to a tag using a transceiver. An uplink signal backscattered from the tag is received and demodulated using the clock signal. The uplink signal has a frequency that is a harmonic of the carrier frequency. A distance between the tag and the transceiver is calculated based on a phase of the demodulated uplink signal. A system for range finding includes a transceiver and a processor. The transceiver modulates a reference signal to a downlink signal and transmits the downlink signal. The transceiver receives and demodulates an uplink signal. The processor is configured to receive the demodulated uplink signal and calculate a distance between the tag and the transceiver using a phase of the demodulated uplink signal.

Hui, Xiaonan↗
DOE OSTI2023

Per-instruction energy debugging using instruction sampling hardware

A processor utilizes instruction based sampling to generate sampling data sampled on a per instruction basis during execution of an instruction. The sampling data indicates what processor hardware was used due to the execution of the instruction. Software receives the sampling data and generates an estimate of energy used by the instruction based on the sampling data. The sampling data may include microarchitectural events and the energy estimate utilizes a base energy amount corresponding to the instruction executed along with energy amounts corresponding to the microarchitectural events in the sampling data. The sampling data may include switching events associated with hardware blocks that switched due to execution of the instruction and the energy estimate for the instruction is based on the switching events and capacitance estimates associated with the hardware blocks.

Wei, Shijia↗
DOE OSTI2023

Health monitoring device

Example aspects of a volatile organic compound detection device, a wearable health monitoring device, and a method of monitoring a user's health are disclosed. The volatile organic compound detection device can comprise a collector comprising a collector material configured to collect volatile organic compounds given off from a user's skin; a separator comprising a gas chromatography column configured to separate mixtures of the volatile organic compounds into their constituent chemicals; and an identifier comprising a detector and a processor, the detector configured to transduce the constituent chemicals into a signal, the processor configured to process the signal to identify specific volatile organic compounds indicative of a health condition.

42 ENGINEERING↗
DOE OSTI2023

Disaggregated system domain

An approach is disclosed that configures a computer system node from components that are each connected to an intra-node network. The configuring is performed by selecting a set of components, including at least one processor, and assigning each of the components a different address range within the node. An operating system is run on the processor included in the node with the operating system accessing each of the assigned components.

Kahle, James A.↗