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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Prompt Phrase Ordering Using Large Language Models in HPC: Evaluating Prompt Sensitivity

Large language models (LLMs) have demonstrated effective performance in domain-specific tasks, often requiring a well-designed prompt to guide their responses. However, optimizing the right prompt is challenging due to prompt sensitivity—the phenomenon where small changes in the prompt can lead to significant variations in performance. In this study, we evaluate prompt performance by examining all permutations of independent phrases to investigate prompt sensitivity and robustness. We used two datasets: the GSM8k dataset, which assesses mathematical reasoning, and a custom template prompt for summarizing database metadata. Our goal was to evaluate the performance across all permutations of a sequence of prompt phrases. The study was conducted using the llama3-instruct- 7B model hosted on Ollama, with computations parallelized in a high-performance computing environment. By comparing the average index of phrases in the best and worst-performing prompts, we found that the order of independent phrases within a prompt significantly impacts LLM performance. Additionally, we used Hamming distance to assess changes between phrase orderings, concluding that prompt modifications can dramatically affect scores, often by almost random chance. These findings support existing research on prompt sensitivity. We discuss the challenges of prompt optimization, noting that altering phrases in a successful prompt does not always result in another successful prompt.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1989

Optical limiting in solutions of metallo-phthalocyanines and naphthalocyanines

Optical limiting measurements have been made on solutions of several metal containing phthalocyanines and naphthalocyanines. Measurements at 532nm using nanosecond pulses from a Q-switched Nd:YAG laser show limiting throughputs of 1-10 millijoules with mild focussing in alcohol solutions with nominal transmissions of 30-70 percent. Measurements on chloro-aluminum-phthalocyanine solutions utilizing individual 30 psec pulses or trains (spanning about 100nsec) of modelocked pulses have shown even lower limiting throughputs. Thus, the dynamic range of the limiting behavior has been shown to cover at least three orders of magnitude. Prompt limiting is attributed to strong singlet-singlet (S1-Sn) absorption, whereas the longer time limiting behavior is postulated to result from strong triplet-triplet (T1-Tn) absorption. In addition to these studies, efforts have been underway to identify materials with reduced limiting throughput and improved optical transmission characteristics.

Coulter, Daniel R.↗
NASA NTRS1994

Constraints placed on the chondrule-forming process by merrihueite in the Mezoe-Madaras chondrite

A few unusual chondrules in the Mezoe-Madaras L3 chondrite contain the peralkaline mineral merrihueite, (K, Na)2(Fe, Mg)5Si12O30, formed by reaction of free silica in the chondrules with K, Na, Fe-rich nebular gas. Vapor fractionation was required to create chondrules poor in Al and rich in Si, and the fractionated condensate produced had to aggregate into protochondrules very promptly (on the order of hours or less) to prevent it from mixing with dust of more generalized composition in the nebula. The traditional paradigm for chondrule formation, involving a series of unrelated events (chemical fractionation of precursor dust; clumping of the dust; melting of the dust-clumps), is inadequate for making these chondrules. A rapid process, all stages of which are related, is required. We propose that this occurred during the cooling and contraction of the volume of hot gas created by a small transient high-energy event in the nebula, of unspecified nature. Microdroplets of silicate melt created by condensation from the cooling, contracting gas had velocity vectors directed toward the center of the volume. Coalescence occurred in the crowded central zone where the microdroplets converged. The Mezoe-Madaras merriihueite-bearing chondrules may have been formed by an atypically low-energy nebular event, which achieved the needed chemical fractionations by only partially vaporizing precursor dust. More commonplace chondrule types may have been created by the same basic process, but involving higher-energy events in which precursor dust was completely vaporized and recondensed.

Wood, John A.↗
DOE OSTI2025

Predictive outlook for experiments resolving prompt vs local redeposition of high- Z materials in tokamaks

High-Z plasma facing components redeposit within the sheath through a combination of two distinct mechanisms: prompt (or geometric-driven) and local (or sheath-driven) redeposition. Experimental efforts are needed to determine the leading-order parameters influencing prompt-vs-local trade-off, which sets the fraction of material entering the scrape-off layer. In preparation for such experiments, leading-order parameters are isolated within the PYEAD-RustBCA-GITR coupled net erosion code using Sobol’ sensitivity analysis. Then, experiments resolving prompt-vs-local trade-off under variation of these leading-order parameters are proposed using an isotopic coupon design with multifaceted diagnostic coverage. The measurability of these experiments is evaluated using synthetic diagnostics.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Early photometric and spectroscopic observations of the extraordinarily bright INTEGRAL-detected GRB 221009A

Context. GRB 221009A, initially detected as an X-ray transient by Swift, was later revealed to have triggered the Fermi satellite about an hour earlier, marking it as a post-peak observation of the event’s emission. This GRB distinguished itself as the brightest ever recorded, presenting an unparalleled opportunity to probe the complexities of GRB physics. The unprecedented brightness, however, challenged observation efforts, as it led to the saturation of several high-energy instruments.Aims. Our study seeks to investigate the nature of the INTEGRAL-detected GRB 221009A and elucidate the environmental conditions conducive to these exceptionally powerful bursts. Moreover, we aim to understand the fundamental physics illuminated by the detection of teraelectronvolt (TeV) photons emitted by GRB 221009A.Methods. We conducted detailed analyses of early photometric and spectroscopic observations that span from the Fermi trigger through to the initial days following the prompt emission phase in order to characterize GRB 221009A’s afterglow, and we complemented these analyses with a comparative study.Results. Our findings from analyzing INTEGRAL data confirm GRB 221009A as the most energetic event observed to date. Early optical observations during the prompt phase negate the presence of bright optical emissions with internal or external shock origins. Spectroscopic analyses enabled us to measure GRB 221009A’s distance and line-of-sight properties. The afterglow’s temporal and spectral analysis suggests prolonged activity of the central engine and a transition in the circumburst medium’s density. Finally, we discuss the implications for fundamental physics of detecting photons as energetic as 18 TeV from GRB 221009A.Conclusions. Early optical observations have proven invaluable for distinguishing between the potential origins of optical emissions in GRB 221009A, underscoring their utility in GRB physics studies. However, the rarity of such data underscores the need for dedicated telescopes capable of synchronous multiwavelength observations. Additionally, our analysis suggests that the host galaxies of TeV GRBs share commonalities with those of long and short GRBs. Expanding the sample of TeV GRBs could further solidify these findings.Key words: techniques: photometric / techniques: spectroscopic / gamma-ray burst: general / gamma-ray burst: individual: GRB 221009A

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1954

NACA Conference on Helicopters a Compilation of the Papers Presented at Langley Aeronautical Laboratory, Langley Field, Va., May 12 and 13, 1954

This document contains reproductions of technical papers presented at the NACA Conference on Helicopters held at the Langley Aeronautical Laboratory May 12 and 13, 1954. The primary purpose of this conference was to convey to the military services, their contractors, and others concerned with the design of helicopters the results of NACA research on helicopters and to provide those attending an opportunity to discuss the results. The papers in this document are in the same form in which they were presented at the conference in order to facilitate their prompt distribution. The original presentation and this record are considered as complementary to, rather than as substitutes for, the Committee's more complete and formal reports . A list of the conferees is included.

Drag↗
NASA NTRS1957

NACA Conference on Aircraft Loads, Structures, and Flutter

This document contains reproductions of technical papers on some of the most recent research results on aircraft loads, flutter, and structures from the NACA laboratories. These papers were presented by members of the staff of the NACA laboratories at the Conference held at the Langley Aeronautical Laboratory March 5, 6, and 7, 1957. The primary purpose of this Conference was to convey to contractors of the military services and others concerned with the design of aircraft these recent research results and to provide those attending an opportunity to discuss the results. The papers in this document are in the same form in which they were presented at the Conference in order to facilitate their prompt distribution. The original presentation and this record are considered as complementary to, rather than as substitutes for, the Committee?s more complete and formal reports. Accordingly, if information from this document is utilized it is requested that this document not be listed as a reference. Individual reports dealing with most of the information presented at the Conference will subsequently be published by NACA and will therefore be suitable as reference material.

Source record↗
NASA NTRS1983

Dependence of radio emission in large H alpha flares 1967-1970 upon the orientation of the local solar magnetic field

Published data on ionizing radiation (as reflected in sudden ionospheric disturbances), H-alpha importance, 10-cm flux, dynamic spectrum, and 200-MHz flux are analyzed for a group of 84 solar flares (from 1967 to 1970) classified by Pudovkin and Chertkov (1976). The group consists of 29 flares with southern orientation of the 100,000-km-scale overlying magnetic field, 32 with northern orientation, and 23 with indeterminate orientation; all have H-alpha importance greater than about 2. Slightly greater X-ray and optical emissions, but one-order-of-magnitude greater prompt 200-MHz and 10-cm fluxes are found in southern as compared to northern-oriented flares. It is inferred that the amount of electromagnetic flare energy radiated promptly from the corona, as compared with that radiated from the chromosphere, was significantly affectly by the orientation of the overlying large-scale magnetic field during the period of observation. This trend is shown to be consistent despite some periodic variation.

Roelof, E. C.↗
NASA NTRS2017

Non-Maximally Decimated Filter Banks Enable Adaptive Frequency Hopping for Unmanned Aircraft Vehicles

In the last few years, radio technologies for unmanned aircraft vehicle (UAV) have advanced very rapidly. The increasing need to fly unmanned aircraft systems (UAS) in the national airspace system (NAS) to perform missions of vital importance to national security, defense, and science has pushed ahead the design and implementation of new radio platforms. However, a lot still has to be done to improve those radios in terms of performance and capabilities. In addition, an important aspect to account for is hardware cost and the feasibility to implement these radios using commercial off-the-shelf (COTS) components. UAV radios come with numerous technical challenges and their development involves contributions at different levels of the design. Cognitive algorithms need to be developed in order to perform agile communications using appropriate frequency allocation while maintaining safe and efficient operations in the NAS and, digital reconfigurable architectures have to be designed in order to ensure a prompt response to environmental changes. Command and control (C2) communications have to be preserved during "standard" operations while crew operations have to be minimized. It is clear that UAV radios have to be software-defined systems, where size, weight and power consumption (SWaP) are critical parameters. This paper provides preliminary results of the efforts performed to design a fully digital radio architecture as part of a NASA Phase I STTR. In this paper, we will explain the basic idea and technical principles behind our dynamic/adaptive frequency hopping radio for UAVs. We will present our Simulink model of the dynamic FH radio transmitter design for UAV communications and show simulation results and FPGA system analysis.

UAV↗
NASA NTRS1991

OH prompt emission in Comet IRAS-Araki-Alcock (1983 VII)

Following Bertaux's (1986) suggestion that photodissociative OH fluorescence can furnish a direct measure of water-density distribution within about 100 km of the cometary nucleus, if sufficiently high spatial resolution is available, attention is presently given to IUE-obtained UV spectra of two comets which differ only as to effective spatial resolution, in order to search for OH prompt emission. IRAS-Araki-Alcock (1983 VII) and Tuttle (1980 XIII) spectra are compared at comparable heliocentric, but differing geocentric, distances; evidence is thereby obtained for OH prompt emission in Comet IRAS-Araki-Alcock, whose implied water-production rate reflects an instantaneous value which may be compared with that derived from OH solar resonance fluorescence.

Budzien, S. A.↗
NASA NTRS2013

Personnel Data Analysis and Retrieval of Phase 1 Move To LC-39 Area

As a technology major from Jackson State University (JSU) I was called in as a summer intern at Kennedy Space Center (KSC) to work in the NASA Engineering, Control and Data Systems (NE-C) Division supporting the Spaceport Command and Control System (SCCS) at the Space Station Processing Facility (SSPF). I was given a two-part project; the first consisted of lending support relocating SCCS Computer Equipment and Project Personnel to the Launch Control Center (LCC). This task involved me using a Microsoft Office data processing tool to assist with the analysis and information management of logistics worth millions of dollars. With the assistance of two other interns, I was responsible for collecting data on equipment used, on a daily basis, by over 200 KSC employees. The many network servers, enterprise switches, desktop computers, and fiber optics had to be handled in an equally prompt and precise manner in order to ensure a minimal amount of equipment down time; which is critical in ensuring a properly secured networking environment. The second part of my project was to assist KSC in developing a more cost effective way of maintaining and taking full advantage of the functionality of some new kiosk units. Since KSC currently has no expert on the servicing and maintenance of the units, I, as a computer technology major, was given the opportunity to assess the hardware and software of the machines. The goal was to learn to establish a secure and remote environment for the kiosks; a goal highly valuing convenience by preserving valuable man-hours saved by not having to travel to each individual kiosk location. In addition, I was to leave a clear and precise plan for future users and administrators of the devices to follow.

Davis, Derrick D.↗
NASA NTRS1983

First-order Fermi acceleration in solar flares as a mechanism for the second-step acceleration of prompt protons and relativistic electrons

Solar flare data from June 27, 1980 balloon-based observations were studied in terms of the hard X ray component. A temporal delay of 3 sec was observed for the X ray emissions above 235 keV. The delay occurred relative to the low-energy electrons and indicated a second acceleration stage. An estimation of the acceleration rate of the first-order Fermi process operating in a closed flare loop was found to be in agreement with the resulting data, including the acceleration of both protons and relativistic electrons. Additional support for the first-order Fermi process is noted in the fact that flares generally occur in magnetic loops, a condition which allows energetic particles to continually interact with the upward moving shock fronts. A correlation has also been observed between the delay times and the H-alpha areas, encouraging the interpretation that the delay times are the shock transit times.

Bai, T.↗
NASA NTRS2017

Significant and Variable Linear Polarization During the Prompt Optical Flash of GRB 160625B

Measurement of polarized light provides a direct probe of magnetic fields in collimated outflows (jets) of relativistic plasma from accreting stellar-mass black holes at cosmological distances. These outflows power brief and intense flashes of prompt gamma-rays known as Gamma Ray Bursts (GRBs), followed by longer-lived afterglow radiation detected across the electromagnetic spectrum. Rapid-response polarimetric observations of newly discovered GRBs have probed the initial afterglow phase. Linear polarization degrees as high as Π∼30% are detected minutes after the end of the prompt GRB emission, consistent with a stable, globally ordered magnetic field permeating the jet at large distances from the central source. In contrast, optical and gamma-ray observations during the prompt phase led to discordant and often controversial results, and no definitive conclusions on the origin of the prompt radiation or the configuration of the magnetic field could be derived. Here we report the detection of linear polarization of a prompt optical flash that accompanied the extremely energetic and long-lived prompt gamma-ray emission from GRB 160625B. Our measurements probe the structure of the magnetic field at an early stage of the GRB jet, closer to the central source, and show that the prompt GRB phase is produced via fast cooling synchrotron radiation in a large-scale magnetic field advected from the central black hole and distorted from dissipation processes within the jet.

High-energy astrophysics↗
NASA NTRS2017

Significant and Variable Linear Polarization During the Prompt Optical Flash of GRB 160625B

Measurement of polarized light provides a direct probe of magnetic fields in collimated outflows (jets) of relativistic plasma from accreting stellar-mass black holes at cosmological distances. These outflows power brief and intense flashes of prompt gamma-rays known as Gamma Ray Bursts (GRBs), followed by longer-lived afterglow radiation detected across the electromagnetic spectrum. Rapid-response polarimetric observations of newly discovered GRBs have probed the initial afterglow phase. Linear polarization degrees as high as Π∼30% are detected minutes after the end of the prompt GRB emission, consistent with a stable, globally ordered magnetic field permeating the jet at large distances from the central source. In contrast, optical and gamma-ray observations during the prompt phase led to discordant and often controversial results, and no definitive conclusions on the origin of the prompt radiation or the configuration of the magnetic field could be derived. Here we report the detection of linear polarization of a prompt optical flash that accompanied the extremely energetic and long-lived prompt gamma-ray emission from GRB 160625B. Our measurements probe the structure of the magnetic field at an early stage of the GRB jet, closer to the central source, and show that the prompt GRB phase is produced via fast cooling synchrotron radiation in a large-scale magnetic field advected from the central black hole and distorted from dissipation processes within the jet.

High-energy astrophysics↗
NASA NTRS2023

First VLTI/GRAVITY Observations of HIP 65426 b: Evidence for a Low or Moderate Orbital Eccentricity

Giant exoplanets have been directly imaged over orders of magnitude of orbital separations, prompting theoretical and observational investigations of their formation pathways. In this paper, we present new VLTI/GRAVITY astrometric data of HIP 65426 b, a cold, giant exoplanet which is a particular challenge for most formation theories at a projected separation of 92 au from its primary. Leveraging GRAVITY's astrometric precision, we present an updated eccentricity posterior that disfavors large eccentricities. The eccentricity posterior is still prior dependent, and we extensively interpret and discuss the limits of the posterior constraints presented here. We also perform updated spectral comparisons with self-consistent forward-modeled spectra, finding a best-fit ExoREM model with solar metallicity and C/O = 0.6. An important caveat is that it is difficult to estimate robust errors on these values, which are subject to interpolation errors as well as potentially missing model physics. Taken together, the orbital and atmospheric constraints paint a preliminary picture of formation inconsistent with scattering after disk dispersal. Further work is needed to validate this interpretation. Analysis code used to perform this work is available on GitHub: https://github.com/sblunt/hip65426.

Sarah Blunt↗
NASA NTRS2005

GRB 050117: Simultaneous Gamma-ray and X-ray Observations with the Swift Satellite

The Swift Gamma-Ray Burst Explorer performed its first autonomous, X-ray follow-up to a newly detected GRB on 2005 January 17, within 193 seconds of the burst trigger by the Swift Burst Alert Telescope. While the burst was still in progress, the X-ray Telescope obtained a position and an image for an un-catalogued X-ray source; simultaneous with the gamma-ray observation. The XRT observed flux during the prompt emission was 1.1 x 10(exp -8) ergs/sq cm/s in the 0.5-10 keV energy band. The emission in the X-ray band decreased by three orders of magnitude within 700 seconds, following the prompt emission. This is found to be consistent with the gamma-ray decay when extrapolated into the XRT energy band. During the following 6.3 hours, the XRT observed the afterglow in an automated sequence for an additional 947 seconds, until the burst became fully obscured by the Earth limb. A faint, extremely slowly decaying afterglow, alpha=-0.21, was detected. Finally, a break in the lightcurve occurred and the flux decayed with alpha<-1.2. The X-ray position triggered many follow-up observations: no optical afterglow could be confirmed, although a candidate was identified 3 arcsecs from the XRT position.

Hill, J. E.↗
DOE OSTI2025

Prompt-Based Development of Domain-Specific Taxonomies

Framework for interacting with prompt-based LLMs (Large Language Models such as, but not limited to, ChatGPT) in order to develop domain specific taxonomies. The software itself is a series of prompts designed to extract hierarchical taxonomy categories from an LLM, as well as guidelines for how to fine-tune LLMs in order to provide better domain-specific taxonomic categories.

Grundy, Jon [Pacific Northwest National Laboratory↗
NASA NTRS2011

Panchromatic Observations of the Textbook GRB 110205A: Constraining Physical Mechanisms of Prompt Emission and Afterglow

We present a comprehensive analysis of a bright, long duration (T(sub 90) approx. 257 s) GRB 110205A at redshift z = 2.22. The optical prompt emission was detected by Swift/UVOT, ROTSE-IIIb and BOOTES telescopes when the GRB was still radiating in the gamma-ray band. Thanks to its long duration, nearly 200 s of observations were obtained simultaneously from optical, X-ray to gamma-ray (1 eV - 5 MeV), which makes it one of the exceptional cases to study the broadband spectral energy distribution across 6 orders of magnitude in energy during the prompt emission phase. In particular, by fitting the time resolved prompt spectra, we clearly identify, for the first time, an interesting two-break energy spectrum, roughly consistent with the standard GRB synchrotron emission model in the fast cooling regime. Although the prompt optical emission is brighter than the extrapolation of the best fit X/ -ray spectra, it traces the -ray light curve shape, suggesting a relation to the prompt high energy emission. The synchrotron + synchrotron self-Compton (SSC) scenario is disfavored by the data, but the models invoking a pair of internal shocks or having two emission regions can interpret the data well. Shortly after prompt emission (approx. 1100 s), a bright (R = 14.0) optical emission hump with very steep rise ( alpha approx. 5.5) was observed which we interpret as the emission from the reverse shock. It is the first time that the rising phase of a reverse shock component has been closely observed.

Zheng, W.↗