Intelligent perturbation algorithms for space scheduling optimization

Intelligent perturbation algorithms for space scheduling optimization are presented in the form of the viewgraphs. The following subject areas are covered: optimization of planning, scheduling, and manifesting; searching a discrete configuration space; heuristic algorithms used for optimization; use of heuristic methods on a sample scheduling problem; intelligent perturbation algorithms are iterative refinement techniques; properties of a good iterative search operator; dispatching examples of intelligent perturbation algorithm and perturbation operator attributes; scheduling implementations using intelligent perturbation algorithms; major advances in scheduling capabilities; the prototype ISF (industrial Space Facility) experiment scheduler; optimized schedule (max revenue); multi-variable optimization; Space Station design reference mission scheduling; ISF-TDRSS command scheduling demonstration; and example task - communications check

Intelligent perturbation algorithms to space scheduling optimization

The limited availability and high cost of crew time and scarce resources make optimization of space operations critical. Advances in computer technology coupled with new iterative search techniques permit the near optimization of complex scheduling problems that were previously considered computationally intractable. Described here is a class of search techniques called Intelligent Perturbation Algorithms. Several scheduling systems which use these algorithms to optimize the scheduling of space crew, payload, and resource operations are also discussed

Study of onboard expert systems to augment space shuttle and space station autonomy

The feasibility of onboard crew activity planning was examined. The use of expert systems technology to aid crewmembers in locating stowed equipment was also investigated. The crew activity planning problem, along with a summary of past and current research efforts, was discussed in detail. The requirements and specifications used to develop the crew activity planning system was also defined. The guidelines used to create, develop, and operate the MFIVE Crew Scheduler and Logistics Clerk were discussed. Also discussed is the mathematical algorithm, used by the MFIVE Scheduler, which was developed to aid in optimal crew activity planning

Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 1: Telepresence technology base development

The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program is presented, leading to an operational telepresence servicer

Space applications of Automation, Robotics And Machine Intelligence Systems (ARAMIS). Volume 3, phase 2: Executive summary

The field of telepresence is defined, and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA's plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies are included. Several space projects are examined in detail to determine what capabilities are required of a telepresence system in order to accomplish various tasks, such as servicing and assembly. The key operational and technological areas are identified, conclusions and recommendations are made for further research, and an example developmental program leading to an operational telepresence servicer is presented

Space Applications of Automation, Robotics and Machine Intelligence Systems (ARAMIS), phase 2. Volume 2: Telepresence project applications

The field of telepresence is defined and overviews of those capabilities that are now available, and those that will be required to support a NASA telepresence effort are provided. Investigation of NASA' plans and goals with regard to telepresence, extensive literature search for materials relating to relevant technologies, a description of these technologies and their state of the art, and projections for advances in these technologies over the next decade are included

Development and Field Evaluation of an Aquifer Stratification Testing System

An aquifer stratification testing system was designed, constructed, and tested. The system was designed to characterize vertical profiles of both quantity and quality of water produced from actively pumping groundwater wells. During testing, all systems functioned properly and either met or exceeded anticipated performance requirements. The system was first tested in an irrigation well completed in the Edwards aquifer and owned by the Onion Creek Club located in Manchaca, Texas, just south of Austin. The purpose of the exercise was to assess test systems performance and to develop and refine testing procedures. Dye-tracer injection tests were performed at five depths from 325 to 405 ft, and a velocity/discharge profile was generated for that interval. The profile was consistent with the karst nature of the Edwards aquifer. Water sampling procedures were tested and evaluated, but no samples were analyzed. Further testing was performed in two public water supply wells completed in the Ogallala Formation of the High Plains aquifer and belonging to the City of Wolfforth, Texas, to investigate arsenic and fluoride concentration distributions, which both exceed maximum contaminant level (MCL) standards for arsenic (10 μg/L) and fluoride (4 mg/L) in produced water. The results indicated vertical trends in both arsenic and fluoride aquifer concentration profiles, although concentrations at all depths exceeded MCL standards for both arsenic and fluoride. Despite distinctly different water discharge profiles between wells, a consistent inverse depth relationship between arsenic and fluoride concentrations was identified in both wells. Aquifer arsenic concentrations generally decreased, and aquifer fluoride concentrations generally increased with increasing depth. Aquifer arsenic concentrations ranged from 11.4 to 14.1 μg/L in Well 8 and from 16.0 to 22.2 μg/L in Well 5. Aquifer fluoride concentrations ranged from 5.53 to 7.98 mg/L in Well 8 and from 4.28 to 5.87 mg/L in Well 5. Future system and procedural modifications should focus on improving and enhancing the flexibility and data acquisition capabilities of the system. Future field testing programs should be performed to develop a water quality stratification database to enhance general understanding of groundwater quality and flow processes and provide insight on potential contamination sources.Bureau of Economic Geolog

Monitoring and modeling infiltration–recharge dynamics of managed aquifer recharge with desalinated seawater

We study the relation between surface infiltration and groundwater recharge during managed aquifer recharge (MAR) with desalinated seawater in an infiltration pond, at the Menashe site that overlies the northern part of the Israeli Coastal Aquifer. We monitor infiltration dynamics at multiple scales (up to the scale of the entire pond) by measuring the ponding depth, sediment water content and groundwater levels, using pressure sensors, single-ring infiltrometers, soil sensors, and observation wells. During a month (January 2015) of continuous intensive MAR (2.45  ×  10⁶ m³ discharged to a 10.7 ha area), groundwater level has risen by 17 m attaining full connection with the pond, while average infiltration rates declined by almost 2 orders of magnitude (from  ∼  11 to  ∼  0.4 m d⁻¹). This reduction can be explained solely by the lithology of the unsaturated zone that includes relatively low-permeability sediments. Clogging processes at the pond-surface – abundant in many MAR operations – are negated by the high-quality desalinated seawater (turbidity  ∼  0.2 NTU, total dissolved solids  ∼  120 mg L⁻¹) or negligible compared to the low-permeability layers. Recharge during infiltration was estimated reasonably well by simple analytical models, whereas a numerical model was used for estimating groundwater recharge after the end of infiltration. It was found that a calibrated numerical model with a one-dimensional representative sediment profile is able to capture MAR dynamics, including temporal reduction of infiltration rates, drainage and groundwater recharge. Measured infiltration rates of an independent MAR event (January 2016) fitted well to those calculated by the calibrated numerical model, showing the model validity. The successful quantification methodologies of the temporal groundwater recharge are useful for MAR practitioners and can serve as an input for groundwater flow models

Impact of Face Masks on Audiovisual Word Recognition in Young Children with Hearing Loss During the Covid-19 Pandemic

Objective: To investigate effects of surgical and transparent face masks during the Covid-19 pandemic on audiovisual speech recognition of words for deaf and hard-of-hearing children. Design: Recorded Word Intelligibility by Picture Identification test (WIPI) was presented in quiet via a computer monitor to children in a quiet test room. The acoustic power spectra of each mask type were compared to the baseline no mask condition. Percent correct word recognition was recorded for four mask conditions (no mask, surgical mask, transparent apron mask and ClearMask) in counterbalanced order. Repeated measures ANOVA was used to test for significant differences in word recognition scores across mask types. Study Sample: Thirteen children (3 to 7 years) in a private auditory oral school wearing hearing aids, bone-anchored hearing aids or cochlear implants. Children were excluded if English was not their primary language or if they had a severe speech-language delay, uncorrected vision loss, or developmental disorder that would affect the results. No children had been exposed to or had contracted the Covid-19 virus. Results: Acoustic spectra showed a decrease in the 2000-8000 Hz region for the transparent apron mask. The surgical mask and ClearMask showed fewer acoustic effects. Children with hearing aids performed similarly to children with cochlear implants. Word recognition was significantly poorer for surgical masks and transparent apron masks. The ClearMask condition was not significantly worse than the no mask condition for words in quiet. Conclusions: Standard surgical and custom apron shield masks significantly hampered word recognition, even in quiet conditions. The commercially available ClearMask did not significantly affect scores in quiet for young deaf and hard-of-hearing children, but scores were highly variable

Transistors

Contains reports on eight research projects.Lincoln Laboratory under Contract AF19(122)-45