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At least 487 records · Page 27

Survey of U.S. Ancillary Services Markets

In addition to providing energy to end-consumers, power system operators are also responsible for ensuring system reliability. To this end, power markets maintain an array of ancillary services to ensure it is always possible to balance the supply and demand for energy in real-time. A subset of these ancillary services are commonly procured through market-based mechanisms: namely, Regulation, Spinning, and Non-spinning Reserves.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗

Advancing User Supports with a Structured How-To Knowledge Base for Earth Science Data

It is a challenge to access and process fast growing Earth science data from satellites and numerical models, which may be archived in very different data format and structures. NASA data centers, managed by the Earth Observing System Data and Information System (EOSDIS), have developed a rich and diverse set of data services and tools with features intended to simplify finding, downloading, and working with these data. Although most data services and tools have user guides, many users still experience difficulties with accessing or reading data due to varying levels of familiarity with data services, tools, and/or formats. A type of structured online document, data recipe, were created in beginning 2013 by Goddard Earth Science Data and Information Services Center (GES DISC). A data recipe is the How-To document created by using the fixed template, containing step-by-step instructions with screenshots and examples of accessing and working with real data. The recipes has been found to be very helpful, especially to first-time-users of particular data services, tools, or data products. Online traffic to the data recipe pages is significant to some recipes. In 2014, the NASA Earth Science Data System Working Group (ESDSWG) for data recipes was established, aimed to initiate an EOSDIS-wide campaign for leveraging the distributed knowledge within EOSDIS and its user communities regarding their respective services and tools. The ESDSWG data recipe group started with inventory and analysis of existing EOSDIS-wide online help documents, and provided recommendations and guidelines and for writing and grouping data recipes. This presentation will overview activities of creating How-To documents at GES DISC and ESDSWG. We encourage feedback and contribution from users for improving the data How-To knowledge base.

how-to↗

Future DCS objectives in communication network timing and synchronization

The Defense Communication System will be moving rapidly toward providing switched digital service to it's users within the next ten years. The principal driving force in the transition to a digital system is the requirement for high performance secure voice service. Additionally, the anticipated data requirements in this time frame can be handled most effectively by a digital network. The characteristics of a switched digital network which impose timing and synchronization requirements on the system design are presented. Several alternative approaches to implementing a timing subsystem suitable for a switched digital communications system have been considered. These include pulse stuffing, independent stable clocks, and clock correction techniques. The advantages and disadvantages of each approach are discussed relative to both the strategic and tactical communication system requirements.

Mensch, J. R.↗

Some Aeronautical Communications Experiments

Classically there has existed an asymmetry between the computing and communicating sides of aerospace systems. Over the past few decades, this asymmetry has shifted to favoring communication link technologies, meaning that advancements in available central processing units (CPUs), storage devices, and internal data buses have stagnated. Indeed, the increased emphasis placed on refining subsystem performance such as with antenna bandwidth in phased arrays, amplifier power efficiency, software defined radio (SDR) flexibility and encoding for data compression and error correction has given rise to successful debuts of multi-gigabit-per-second data return from long space-link distances. These accomplishments are easily quantifiable through link budgets and illustrate what is possible, but also reveal the deficiencies in overall communications capabilities. In particular, the ever-accelerating presence of aerospace vehicles gives rise to newer and larger classes of challenges to address the needs of 21st century systems. Furthermore remote sensing and imaging capabilities have far outpaced our ability to transmit their products to the ground, so we are increasingly dependent on pre-processing and downselection to contend with the communications bottleneck. No longer may we depend upon the constrained logistics in delivering end-to-end data delivery through manual reconfigurations, static event scheduling and execution on a per-vehicle basis, for these methods do not scale and therefore must give way to dynamic, networked approaches with an overall systems view in mind. Emerging mission requirements exhibit a trend toward multiple smaller-scale vehicles working together to perform dissimilar observations. Such operations necessitate sensor fusion across a constellation, and where data processing may be distributed throughout a fairly disconnected network whose topology changes over time in non-deterministic manners. Individual communications link performance is still very relevant to deploying an effective communications system, but now must be embedded within a greater architecture of capability to optimally utilize the bandwidth available from each link to generate an ultimate end-to-end quality of service. The deleterious effects of timing uncertainty across the arrangement presents a challenge to measurement synchronization and delivery, so a successful deployed system needs to be tolerant to the delays inherent in time-of-light between elements and digital processing latencies existing at each node. In this presentation we share the flight test results from a high performance Gbps laser communications terminal evaluated with a suite of store and forward capabilities called High-rate Delay Tolerant Networking (HDTN). The communications payload is operated over Lake Erie across a range of configurations including several convergence layers, and is evaluated to determine recovery time after link disruptions, information loss, efficiency and speed. The effectiveness of utilizing a flying laboratory to increase the Technology Readiness Level (TRL) of an integrated system in relevant environments is discussed, as well as the value of conducting aeronautics experiments to retire risk for technology infusion into space missions. Upcoming flight campaigns will be presented, including opportunities to demonstrate secure command and control, data intensive hyperspectral imaging, quantum link characterization, 4k High Definition (HD) video streaming and internetworked space-ground-aero relay operations. These experiments will pave the way for future missions which will depend upon interoperability across disparate government and privately owned networks, involve contention with uncertain and dynamic timing, and require agility to autonomously configure optimal parameters across networks of ever-increasing size and complexity to ensure data delivery. https://www1.grc.nasa.gov/space/scan/acs/tech-studies/dtn/

Daniel Raible↗

A comparison of the domestic satellite communications forecast to the year 2000

The methodologies and results of three NASA-sponsored market demand assessment studies are presented and compared. Forecasts of future satellite addressable traffic (both trunking and customer premises services) were developed for the three main service categories of voice, data and video and subcategories thereof for the benchmark years of 1980, 1990 and 2000. The contractor results are presented on a service by service basis in two formats: equivalent 36 MHz transponders and basic transmission units (voice: half-voice circuits, data: megabits per second and video: video channels). It is shown that while considerable differences exist at the service category level, the overall forecasts by the two contractors are quite similar. ITT estimates the total potential satellite market to be 3594 transponders in the year 2000 with data service comprising 54 percent of this total. The WU outlook for the same time period is 2779 transponders with voice services accounting for 66 percent of the total.

Poley, W. A.↗

Commercialization and Human Settlement of the Moon and Cislunar Space – A Look Ahead at the Possibilities over the Next 50 Years

Over 50 years have passed since the movie 2001: A Space Odyssey debuted in April 1968. In the film, Dr. Heywood Floyd flies to a large artificial gravity space station orbiting Earth aboard a commercial space plane. He then embarks on a commuter flight to the Moon arriving there 25hours later. Today, on the 50th anniversary of the Apollo 11 lunar landing, the images portrayed in 2001 still remain well beyond our capabilities. This paper examines key technologies and systems (in-situ resource utilization, fission power, advanced chemical and nuclear propulsion),and orbiting infrastructure elements (providing a propellant depot and cargo transfer function),that could be developed by NASA and the private sector in future decades allowing the operational capabilities presented in 2001 to be achieved, albeit on a more spartan scale. Lunar derived propellants (LDPs) will be essential to reducing the launch mass requirements from Earth and developing a reusable lunar transportation system (LTS) that can allow initial outposts to evolve into settlements supporting a variety of commercial activities like in-situ propellant production. Deposits of icy regolith found within permanently shadowed craters at the lunar pole scan supply the feedstock material to produce liquid oxygen (LO2) and hydrogen (LH2) propellan tneeded by surface-based lunar landing vehicles (LLVs) using chemical rocket engines. Along the Moon's nearside equatorial corridor, iron oxide-rich volcanic glass beads from vast pyroclasticdeposits, together with mare regolith, can provide the materials to produce lunar-derived LO2plus other important solar wind implanted (SWI) volatiles, including H2 and helium-3. Mega watt classfission power systems will be essential for providing continuous "24/7" power to LLVs will provide cargo and passenger "orbit-to-surface" access and willalso be used to transport LDP to Space Transportation Nodes (STNs) located in lunar polar(LPO) and equatorial orbits (LLO). Spaced-based, reusable lunar transfer vehicles (LTVs),operating between STNs in low Earth orbit (LEO), LLO, and LPO, and able to refuel with LDPs,can offer unique mission capabilities including short transit time crewed cargo transports. Even acommuter shuttle service similar to that portrayed in 2001 appears possible, allowing 1-way trip times to and from the Moon as short as 24 hours. The performance of LTVs using both RL10B-2chemical rockets, and a variant of the nuclear thermal rocket (NTR), the LO2-Augmented NTR(LANTR), are examined and compared. The bipropellant LANTR engine utilizes its divergent nozzle section as an afterburner into which oxygen is injected and supersonically combusted with reactor-heated hydrogen emerging from the engine's sonic throat. If only 1% of the LDP obtained from icy regolith, volcanic glass, and SWI volatile deposits were available for use in lunar orbit,such a supply could support routine commuter flights to the Moon for many thousands of years!This paper provides a look ahead at what might be possible in the not too distant future,quantifies the operational characteristics of key in-space and surface technologies and systems,and provides conceptual designs for the various architectural elements discussed.

Borowski, Stanley K.↗

Space station automation study-satellite servicing. Volume 1: Executive summary

A plan for advancing the state of automation and robotics technology as an integral part of the U.S. space station development effort was studied. This study was undertaken: (1) to determine the benefits that will accrue from using automated systems onboard the space station in support of satellite servicing; (2) to define methods for increasing the capacity for, and effectiveness of satellite servicing while reducing demands on crew time and effort and on ground support; (3) to find optimum combinations of men/machine activities in the performance of servicing functions; and (4) project the evolution of automation technology needed to enhance or enable satellite servicing capabilities to match the evolutionary growth of the space station. A secondary intent is to accelerate growth and utilization of robotics in terrestrial applications as a spin-off from the space station program.

Source record↗

Hubble Space Telescope Crew Rescue Analysis

In the aftermath of the 2003 Columbia accident NASA removed the Hubble Space Telescope (HST) Servicing Mission 4 (SM4) from the Space Shuttle manifest. Reasons cited included concerns that the risk of flying the mission would be too high. There was at the time no viable technique to repair the orbiter s thermal protection system if it were to be damaged by debris during ascent. Furthermore in the event of damage, since the mission was not to the International Space Station, there was no safe haven for the crew to wait for an extended period of time for a rescue. The HST servicing mission was reconsidered because of improvements in the ascent debris environment, the development of techniques for the astronauts to perform on orbit repairs to damage thermal protection, and the development of a strategy to provide a crew rescue capability. However, leading up to the launch of servicing mission, the HST crew rescue capability was a recurring topic. For HST there was a limited amount of time available to perform a crew rescue because of the limited consumables available on the Orbiter. The success of crew rescue depends upon several factors including when a problem is identified, when and to what extent power down procedures are begun, and where the rescue vehicle is in its ground processing cycle. Severe power downs maximize crew rescue success but would eliminate the option for the orbiter servicing the HST to attempt a landing. Therefore, crew rescue success needed to be weighed against preserving the ability of the orbiter to have landing option in case there was a problem with the rescue vehicle. This paper focuses on quantification of the HST mission loss of crew rescue capability using Shuttle historical data and various power down capabilities. That work supported NASA s decision to proceed with the HST service mission, which was successfully completed on May 24th 2009.

Hamlin, Teri L.↗

Harvesting biofuel grasslands has mixed effects on natural enemy communities and no effects on biocontrol services

Summary Perennial bioenergy systems, such as switchgrass and restored prairies, are alternatives to commonly used annual monocultures such as maize. Perennial systems require lower chemical input, provide greater ecosystem services such as carbon storage, greenhouse gas mitigation and support greater biodiversity of beneficial insects. However, biomass harvest will be necessary in managing these perennial systems for bioenergy production, and it is unclear how repeated harvesting might affect ecosystem services. In this study, we examined how repeated production‐scale harvesting of diverse perennial grasslands influences vegetation structure, natural enemy communities (arthropod predators and parasitoids), and natural biocontrol services in two states (Wisconsin and Michigan, USA) over multiple years. We found that repeated biomass harvest reduced litter biomass and increased bare ground cover. Some natural enemy groups, such as ground‐dwelling arthropods, decreased in abundance with harvest, whereas others such as foliar‐dwelling arthropods increased in abundance. The disparity in responses is likely due to how different taxonomic groups utilize vegetation and differences in dispersal abilities. At the community level, biomass harvest altered community composition, increased total arthropod abundance and decreased evenness but did not influence species richness, diversity or biocontrol services. Harvest effects varied with time, diminishing in strength both within the season (for total abundance and evenness), across seasons (for evenness) or were consistent throughout the duration of the study (for community composition). Greater functional redundancy and compensatory responses of the different taxonomic groups may have buffered against the potentially negative effects of harvest on biocontrol services. Synthesis and applications . Our results show that in the short‐term, repeated harvesting of perennial grasslands (when insect activity is low) consistently altered vegetation structure but had mixed effects on natural enemy communities and no discernible effects on biocontrol services. However, the long‐term effects of repeated harvesting on vegetation structure, natural enemies and other arthropod‐derived ecosystem services such as pollination and decomposition remain largely unknown.

Kim, Tania N.↗

Data from: Harvesting biofuel grasslands has mixed effects on natural enemy communities and no effects on biocontrol services

1.Perennial bioenergy systems, such as switchgrass and restored prairies, are alternatives to commonly used annual monocultures such as maize. Perennial systems require lower chemical input, provide greater ecosystem services such as carbon storage, greenhouse gas mitigation, and support greater biodiversity of beneficial insects. However, biomass harvest will be necessary in managing these perennial systems for bioenergy production, and it is unclear how repeated harvesting might affect ecosystem services. 2.In this study, we examined how repeated production-scale harvesting of diverse perennial grasslands influences vegetation structure, natural enemy communities (arthropod predators and parasitoids), and natural biocontrol services in two states (Wisconsin and Michigan, USA) over multiple years. 3.We found that repeated biomass harvest reduced litter biomass and increased bare ground cover. Some natural enemy groups, such as ground-dwelling arthropods, decreased in abundance with harvest whereas others, such as foliar-dwelling arthropods increased in abundance. The disparity in responses is likely due to how different taxonomic groups utilize vegetation and differences in dispersal abilities. 4.At the community level, biomass harvest altered community composition, increased total arthropod abundance, and decreased evenness but did not influence species richness, diversity, or biocontrol services. Harvest effects varied with time, diminishing in strength both within the season (for total abundance and evenness), across seasons (for evenness), or were consistent throughout the duration of the study (for community composition). Greater functional redundancy and compensatory responses of the different taxonomic groups may have buffered against the potentially negative effects of harvest on biocontrol services. 5.Synthesis and applications. Our results show that in the short-term, repeated harvesting of perennial grasslands (when insect activity is low) consistently altered vegetation structure but had mixed effects on natural enemy communities and no discernable effects on biocontrol services. However, the long-term effects of repeated harvesting on vegetation structure, natural enemies, and other arthropod-derived ecosystem services such as pollination and decomposition remain largely unknown.

09 BIOMASS FUELS↗

Scientific and technical photography at NASA Langley Research Center

As part of my assignment connected with the Scientific and Technical Photography & Lab (STPL) at the NASA Langley Research Center I conducted a series of interviews and observed the day to day operations of the STPL with the ultimate objective of becoming exposed first hand to a scientific and technical photo/imaging department for which my school prepares its graduates. I was also asked to share my observations with the staff in order that these comments and observations might assist the STPL to better serve its customers. Meetings with several individuals responsible for various wind tunnels and with a group that provides photo-optical instrumentation services at the Center gave me an overview of the services provided by the Lab and possible areas for development. In summary form these are some of the observations that resulted from the interviews and daily contact with the STPL facility. (1) The STPL is perceived as a valuable and almost indispensable service group within the organization. This comment was invariably made by everyone. Everyone also seemed to support the idea that the STPL continue to provide its current level of service and quality. (2) The STPL generally is not perceived to be a highly technically oriented group but rather as a provider of high quality photographic illustration and documentation services. In spite of the importance and high marks assigned to the STPL there are several observations that merit consideration and evaluation for possible inclusion into the STPL's scope of expertise and future operating practices. (1) While the care and concern for artistic rendition of subjects is seen as laudable and sometimes valuable, the time that this often requires is seen as interfering with keeping the tunnels operating at maximum productivity. Tunnel managers would like to shorten down-time due to photography, have services available during evening hours and on short notice. It may be of interest to the STPL that tunnel managers are incorporating ever greater imaging capabilities in their facilities. To some extent this could mean a reduced demand for traditional photographic services. (2) The photographic archive is seen as a Center resource. Archiving of images, as well as data, is a matter of concern to the investigators. The early holdings of the Photographic Archives are quickly deteriorating. The relative inaccessibility of the material held in the archives is problematic. (3) In certain cases delivery or preparation of digital image files instead of, or along with, hardcopy is already being perceived by the STPL's customers as desirable. The STPL should make this option available, and the fact that it has, or will have this capability widely known. (4) The STPL needs to continue to provide expert advice and technical imaging support in terms of application information to users of traditional photographic and new electronic imaging systems. Cooperative demo projects might be undertaken to maintain or improve the capabilities of the Lab. (5) STPL personnel do not yet have significant electronic imaging or electronic communication skills and improvements in this is an area could potentially have a positive impact on the Center. (6) High speed photographic or imaging services are often mentioned by the STPL as being of primary importance to their mission but the lab supports very few projects calling for high speed imaging services. Much high speed equipment is in poor state of repair. It is interesting to note that when the operation of lasers, digital imaging or quantitative techniques are requested these are directed to another NASA department. Could joint activities be initiated to solve problems? (7). The STPL could acquire more technical assignments if examples of the areas where they posses expertise would be circulated around the center. The fact that the STPL owns high speed video capability could be 'advertised' among its customer base if there truly was an interest in building up a customer base in this area. The STPL could participate in events like TOPS as an exhibitor, as well as a documenter, of the event.

Davidhazy, Andrew↗

Design and development of the DAQ and Timing Hub for CMS Phase-2

The CMS detector will undergo a major upgrade for Phase-2 of the LHC program, starting around 2026. The upgraded Level-1 hardware trigger will select events at a rate of 750 kHz. At an expected event size of 7.4 MB this corresponds to a data rate of up to 50 Tbit/s.Optical links will carry the signals from on-detector front-end electronics to back-end electronics in ATCA crates in the service cavern. A DAQ and Timing Hub board aggregates data streams from back-end boards over point-to-point links, provides buffering and transmits the data to the commercial data-to-surface network for processing and storage. This hub board is also responsible for the distribution of timing, control and trigger signals to the back-ends.This paper presents the current development towards the DAQ and Timing Hub and the design of the first prototype, to be used as for validation and integration with the first back-end prototypes in 2019-2020.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

Data Recipes: Toward Creating How-To Knowledge Base for Earth Science Data

Both the diversity and volume of Earth science data from satellites and numerical models are growing dramatically, due to an increasing population of measured physical parameters, and also an increasing variety of spatial and temporal resolutions for many data products. To further complicate matters, Earth science data delivered to data archive centers are commonly found in different formats and structures. NASA data centers, managed by the Earth Observing System Data and Information System (EOSDIS), have developed a rich and diverse set of data services and tools with features intended to simplify finding, downloading, and working with these data. Although most data services and tools have user guides, many users still experience difficulties with accessing or reading data due to varying levels of familiarity with data services, tools, and or formats. The data recipe project at Goddard Earth Science Data and Information Services Center (GES DISC) was initiated in late 2012 for enhancing user support. A data recipe is a How-To online explanatory document, with step-by-step instructions and examples of accessing and working with real data (http:disc.sci.gsfc.nasa.govrecipes). The current suite of recipes has been found to be very helpful, especially to first-time-users of particular data services, tools, or data products. Online traffic to the data recipe pages is significant, even though the data recipe topics are still limited. An Earth Science Data System Working Group (ESDSWG) for data recipes was established in the spring of 2014, aimed to initiate an EOSDIS-wide campaign for leveraging the distributed knowledge within EOSDIS and its user communities regarding their respective services and tools. The ESDSWG data recipe group is working on an inventory and analysis of existing data recipes and tutorials, and will provide guidelines and recommendation for writing and grouping data recipes, and for cross linking recipes to data products. This presentation gives an overview of the data recipe activites at GES DISC and ESDSWG. We are seeking requirements and input from a broader data user community to establish a strong knowledge base for Earth science data research and application implementations.

data recipe↗

Commuter preferences for a first-mile/last-mile microtransit service in the United States

Transportation system models rely heavily upon value of time (VOT) estimates to predict customer behavior. Accurate VOT estimates are particularly vital for planning new services such as on-demand ride hailing or microtransit because customers’ sensitivity to wait time, walk time, and route detour time affects their likelihood of selecting these modes. If an incorrect VOT is assumed during service planning, then ridership will be depressed because of a mismatch between their preferences and how the system is designed. In this paper, we report on the measurement of VOT for microtransit, a shared first-mile/last-mile mobility service, obtained using stated preference microdata from four U.S. cities. Here, we found a median in-vehicle VOT for microtransit of $\$$18.63 (95% CI: $\$$13.39–$\$$24.46) and an access VOT of $\$$75.38 (95% CI: $\$$59.22–$\$$94.96). The former is practically equal to the VOT we found for respondents’ current modes ($\$$20.24, 95% CI: $\$$13.71–$\$$26.94). We also found that men, younger riders, the highly educated, and transit riders are more likely to be interested in microtransit. Since the disutility of time spent on microtransit is not higher than that of other modes, we believe this new service has the potential to attract riders, and particularly if the system is designed with low waiting and walking times.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗

Remote servicing of space systems

Space systems are difficult to maintain on orbit. The difficulty arises from the limited ability and availability of the astronaut work force in the hazardous space environment. Remote robotic manipulation can free the astronaut from the hazardous working environment while also increasing the work force. However, remote robotic servicing is not without its own set of problems and limitations, such as communication time delay and unstructured worksites. Tests and test equipment are described which are designed to increase the understanding of the remote servicing problems and to allow development of potential solutions. A half scale satellite mockup was developed for evaluating and improving upon the design of replaceable subsystems, such as batteries and electronic boxes. A servicer system, that includes a six degree of freedom PUMA 560 robot and interchangeable end effectors (tools), was developed to aid in driving out servicer design requirements. The results include the time delay impact on servicing timelines and requirements for the servicer system.

Collins, S. L.↗

LIS-Hydro: Authoritative Source for OCONUS Hydro-Intelligence

U.S. military forces are often tasked to participate in a variety of transboundary water-related decision-making activities, including humanitarian assistance operations through Department of State tasking, support of in-country infrastructure development activities that help develop or improve diplomatic relationships, and support of transboundary water treaty negotiations or disputes to reduce risk of conflict caused by water security issues. The U.S. intelligence communities have identified the coordination over shared water resources as an area of significant concern to U.S. national security (U.S. National Defense Strategy, 2018). Such transboundary water issues are projected to intensify in the future under increasingly complex population dynamics, political tensions due to parallel issues, and a changing climate. A 2017 joint NASA, USACE/RDC, and U.S. Air Force co-sponsored workshop revealed a lack of sufficient decision support tools and access to timely technical and contextual information needed to assess and respond to potential water-related threats around the world. The need for an integrated operational service, with the capacity to combine and synthesize hydrological modeling, assimilation, forecasting, and visualization capabilities across the U.S. Government, was highlighted as a key recommendation. In direct response, a subset of the U.S. Department of Defense, National Intelligence Community, and Oak Ridge National Laboratory are collaborating on the development of a fully integrated hydro-modeling and streamflow prediction system (i.e., LIS-Hydro). Completion of the project and sustainment of the operational capability by Air Force Weather will establish a national asset to assist federal agencies implement government-wide strategies around water resources (U.S. Global Water Strategy, 2017). The hydrological products and services will, for the very first time, establish a routinely available authoritative source of global water intelligence information supporting war-fighters, planners, and decision makers at all echelons and services of the U.S. military, Federal government, and intelligence community. A summary of the interagency scientific collaboration in addressing some of the key gaps and needs identified during the 2017 workshop will be presented.

Land Information System↗

SU-F-T-518: Development and Characterization of a Gated Treatment System Implemented with An In-House Optical Tracking System and the Elekta Response Interface

Purpose: To report the development and characterization of the first in-house gating system implemented with an optical tracking system (OTS) and the Elekta Response™ interface. Methods: The Response™ connects a patient tracking system with a linac, enabling the tracking system to control radiation delivery. The developed system uses an in-house OTS to monitor patient breathing. The OTS consists of two infrared-based cameras, tracking markers affixed on patient. It achieves gated or breath-held (BH) treatment by calling beam ON/OFF functions in the Response™ dynamic-link library (DLL). A 4D motion phantom was used to evaluate its dosimetric and time delay characteristics. Two FF- and two FFF-IMRT beams were delivered in non-gated, BH and gated mode. The sinusoidal gating signal had a 6 sec period and 15 mm amplitude. The duty cycle included 10%, 20%, 30% and 50%. The BH signal was adapted from the sinusoidal wave by inserting 15 sec BHs. Each delivery was measured with a 2D diode array (MapCHECK™) and compared with the non-gated delivery using gamma analysis (3%). The beam ON/OFF time was captured using the service graphing utility of the linac. Results: The gated treatments were successfully delivered except the 10% duty cycle. The BH delivery had perfect agreement (100%) with non-gated delivery; the agreement of gated delivery decreased from 99% to 88% as duty cycle reduced from 50% to 20%. The beam on/off delay was on average 0.25/0.06 sec. The delivery time for the 50%, 30% and 20% duty cycle increased by 29%, 71% and 139%, respectively. No dosimetric or time delay difference was noticed between FF- and FFF-IMRT beams. Conclusion: The in-house gating system was successfully developed with dosimetric and time delay characteristics in line with published results for commercial systems. It will be an important platform for further research and clinical development of gated treatment.

43 PARTICLE ACCELERATORS↗

Linear Regression Model for Predictive Service Provider Selection

The increasing number of satellites in orbit has led to a growing reliance on third-party service providers for data transfer between Earth and space. Traditional approaches to managing satellite communications require human intervention, which becomes more burdensome with the escalating number of satellites. This research addresses the need for an efficient and automated system to optimize service provider selection for NASA space communication. Previous research has utilized human-operated approaches for service provider management. Our study fills a gap by developing a cognitive algorithm that automates and optimizes the selection process based on various parameters, such as data volume, priority, quality of service and cost. This novel solution reduces user burden, facilitates service management, and contributes to the development of cognitive spaceflight missions, ultimately supporting NASA’s research into Cognitive Communications technology. The algorithm design consists of three major steps: modeling data, developing a Link Selection Algorithm (LSA) based on a grading system, and applying machine learning using linear regression. The LSA evaluates providers based on user-defined constraints, considering factors such as delivery time, cost, and quality of service. We define a suitability metric which allows our algorithm to make a recommendation to a user regarding which commercial service providers to select. The addition of Linear Regression predicts the future suitability value. Our main findings demonstrate that the resulting algorithm can autonomously manage connections between satellites and providers, maximizing communication channel efficiency. This research has significant implications, as it not only addresses a pressing issue in satellite communication management but also advances the field of cognitive spaceflight missions.

Linear regression↗