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Surface Turbulent Fluxes, 1x1 deg Daily Grid, Set1 V2c
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T08:49:10.000ZThese data are the Goddard Satellite-based Surface Turbulent Fluxes Version-2c (GSSTF2c) Dataset recently produced through a MEaSUREs funded project led by Dr. Chung-Lin Shie (UMBC/GEST, NASA/GSFC), converted to HDF-EOS5 format. The stewardship of this HDF-EOS5 dataset is part of the MEaSUREs project, http://earthdata.nasa.gov/our-community/community-data-system-programs/measures-projects/surface-turbulent-fluxes-esdr http://earthdata.nasa.gov/our-community/community-data-system-programs/measures-projects GSSTF version 2b (Shie et al. 2010, Shie et al. 2009) generally agreed better with available ship measurements obtained from several field experiments in 1999 than GSSTF2 (Chou et al. 2003) did in all three flux components, i.e., latent heat flux [LHF], sensible heat flux [SHF], and wind stress [WST] (Shie 2010a,b). GSSTF2b was also found favorable, particularly for LHF and SHF, in an intercomparison study that accessed eleven products of ocean surface turbulent fluxes, in which GSSTF2 and GSSTF2b were also included (Brunke et al. 2011). However, a temporal trend appeared in the globally averaged LHF of GSSTF2b, particularly post year 2000. Shie (2010a,b) attributed the LHF trend to the trends originally found in the globally averaged SSM/I Tb's, i.e., Tb(19v), Tb(19h), Tb(22v) and Tb(37v), which were used to retrieve the GSSTF2b bottom-layer (the lowest atmospheric 500 meter layer) precipitable water [WB], then the surface specific humidity [Qa], and subsequently LHF. The SSM/I Tb's trends were recently found mainly due to the variations/trends of Earth incidence angle (EIA) in the SSM/I satellites (Hilburn and Shie 2011a,b). They have further developed an algorithm properly resolving the EIA problem and successfully reproducing the corrected Tb's by genuinely removing the "artifactitious" trends. An upgraded production of GSSTF2c (Shie et al. 2011) using the corrected Tb's has been completed very recently. GSSTF2c shows a significant improvement in the resultant WB, and subsequently the retrieved LHF - the temporal trends of WB and LHF are greatly reduced after the proper adjustments/treatments in the SSM/I Tb's (Shie and Hilburn 2011). In closing, we believe that the insightful "Rice Cooker Theory" by Shie (2010a,b), i.e., "To produce a good and trustworthy 'output product' (delicious 'cooked rice') depends not only on a well-functioned 'model/algorithm' ('rice cooker'), but also on a genuine and reliable 'input data' ('raw rice') with good quality" should help us better comprehend the impact of the improved Tb on the subsequently retrieved LHF of GSSTF2c. This is the Daily (24-hour) product; data are projected to equidistant Grid that covers the globe at 1x1 degree cell size, resulting in data arrays of 360x180 size. A finer resolution, 0.25 deg, of this product has been released as Version 3. The GSSTF, Version 2c, daily fluxes have first been produced for each individual available SSM/I satellite tapes (e.g., F08, F10, F11, F13, F14 and F15). Then, the Combined daily fluxes are produced by averaging (equally weighted) over available flux data/files from various satellites. These Combined daily flux data are considered as the "final" GSSTF, Version 2c, and are stored in this HDF-EOS5 collection. There are only one set of GSSTF, Version 2c, Combined data, "Set1" It contains 9 variables: "E" 'latent heat flux' (W/m**2), "STu" 'zonal wind stress' (N/m**2), "STv" 'meridional wind stress' (N/m**2), "H" 'sensible heat flux' (W/m**2), "Qair" 'surface air (~10-m) specific humidity' (g/kg), "WB" 'lowest 500-m precipitable water' (g/cm**2), "U" '10-m wind speed' (m/s), "DQ" 'sea-air humidity difference' (g/kg) "Tot_Precip_Water" 'total precipitable water' (g/cm**2) The double-quoted labels are the short names of the data fields in the HDF-EOS5 files. The "individual" daily flux data files, produced for each individual satellite, are also available in HDF-EOS5, although from differe...
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Approximate Cartesian Control for Robotic Tool Usage with Graceful Degradation Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:31:39.000ZMany of NASA's exploration scenarios include important roles for autonomous or partially autonomous robots. It is desirable for them to utilize human tools when possible, rather than needing to build custom tools for each robot. Control of robotic manipulators for tool usage generally requires a very precise Cartesian-space trajectory of the tool tip (e.g., moving a marker along the surface of a whiteboard or rotating a screwdriver about an axis). Well-known techniques exist for manipulator control in Cartesian space, most of which necessitate solving a series of Inverse Kinematics (IK) problems. Closed-form IK solvers work well for 7-degree-of-freedom (DOF) arms with rigid tool attachments, but cannot handle non-rigid tools that slip in the robot's hands. Numerical IK approaches are more generic and can handle non-rigid links to tools, but can be slow to converge. More importantly, if any joints fail or become limited in their range of motion, the robot arm essentially becomes 6-DOF or lower. IK solvers often fail in these lower DOF spaces because the configuration space becomes non-continuous and full of "holes". As a result, a 7-DOF robotic arm in space might be rendered largely useless if a single joint fails or even loses mobility until it can be serviced. TRACLabs proposes to investigate an alternative approach to traditional Cartesian control approaches, which rely on complex IK solvers that go from Cartesian space backwards to joint space. We propose to leverage cheap memory and modern processing speeds to instead perform simple computations that go from joint space forwards to Cartesian space. Such techniques should overcome common changes to a manipulation chain caused by tool slippage or the grasping of a new tool and to overcome uncommon changes to a chain caused by joint failures, reduced joint mobility, changes in joint geometry or range of motion, or added joints.
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Northern Hemisphere EASE-Grid 2.0 Weekly Snow Cover and Sea Ice Extent
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T09:14:22.000ZThe Northern Hemisphere EASE-Grid 2.0 Weekly Snow Cover and Sea Ice Extent Version 4 product combine snow cover and sea ice extent at weekly intervals from 23 October 1978 through 29 June 2014, and snow cover alone from 03 October 1966 through 29 June 2014. Snow cover extent for this data set is based on the NOAA/NCDC Climate Data Record (CDR) of Northern Hemisphere (NH) Snow Cover Extent (SCE) by D. Robinson (2012) and regridded to the EASE-Grid. The NOAA/NCDC CDR of Northern Hemisphere Snow Cover Extent data were derived from the manual interpretation of AVHRR, GOES, and other visible-band satellite data (Helfrich et al. 2007). Sea ice extent is regridded to EASE-Grid from Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data. Designed to facilitate study of Northern Hemisphere seasonal fluctuations of snow cover and sea ice extent, the data set also includes monthly climatologies describing average extent, probability of occurrence, and variance. Data are provided in flat, unsigned binary files and are available via FTP.
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Nimbus-7 SMMR Derived Monthly Global Snow Cover and Snow Depth
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T09:14:15.000ZThe data set consists of monthly global snow cover and snow depth derived from Nimbus-7 SMMR data for 1978 through 1987. The SMMR data are interpolated for spatial and temporal gaps, and averaged for display in polar stereographic projection. Maps are based on six-day average brightness temperature data from the middle week of each month. Data are placed into 1/2 degree latitude by 1/2 degree longitude grid cells uniformly subdividing a polar stereographic map according to the geographic coordinates of the center of the radiometers' fields of view. Overlapping data from separate orbits in the same six-day period are averaged to give a single brightness temperature assumed to be at the cell's center. Oceans and bays are masked so that only microwave data for land areas are displayed. Comparisons of SMMR snow cover maps with previous maps produced by NOAA/NESDIS and US Air Force Global Weather Center indicate that the total snow covered area derived from SMMR is usually about ten percent less than that measured by the earlier products, because passive microwave sensors often can't detect shallow dry snow less than about 5 cm deep. Snow depths are comparable, showing SMMR results to be especially good for uniform snow covered areas such as the Canadian high plains and Russian steppes. Heavily forested and mountainous areas tend to mask the microwave snow signatures, and SMMR snow depth derivations are less reliable in those areas. Formerly distributed by NASA/GSFC/NSSDC and NASA Pilot Land Data System (PLDS), these data are now available via ftp from NSIDC.
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Auditory Presentation of H/OZ Critical Flight Data Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:08:03.000ZAutomation of a flight control system to perform functions normally attributed to humans is often not robust and limited to specific operating conditions and types of operation and a small set of fixed behaviors (i.e. modes). eSky has shown that metrics such as the time delay between a required control input from the crew and the actual input is sensitive to crew functional degradation through external distraction. We are currently developing strategies for using such crew state metrics to modulate the level of automation support provided to the flight crew. Dynamic reallocation of function between crew and automation can reduce the cognitive workload on the crew, enhance their ability to supervise the automation and help them intervene in the event of any failure or operation outside the desired operating conditions. eSky is exploring function reallocation in a collaborative flight control system (HFCS) design pioneered at NASA Langley. HFCS combines precise flight control automation with rudimentary intelligence that the flight crew can guide using relatively simple mechanisms. HFCS automation manages short-term control tasks (e.g. path following) while the crew is required to direct every significant trajectory change using flight controls rather than an FMS interface to keep them engaged in conduct of the flight. The automation communicates intentions to the pilot through visual and haptic (tactile) feedback; the crew communicates intentions to the automation through conventional controls. The HFCS user interface is primarily visual and tactile with limited auditory elements, mainly limited to a few alerts and warnings. eSky proposes to establish the auditory channel as a key element in providing flight dynamic information and cueing of required crew in puts in addition to envelope protection warnings. These new interface elements will be integrated into eSky's evolving strategies for functionality reallocation of between automation and crew.
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Procedure Execution and Projection System
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:15:38.000ZThere is a persistent pressure upon NASA crew members to achieve very high productivity during their missions. Significant challenges exist to maintaining manageable workload while the crew is performing their many and varied tasks allotted for each day while ensuring the crew maintain situation awareness. NASA crew members deal with a large amount of very high technology equipment and perform experiments and procedures that can be extremely long and complex. The solution will require the development of automated management technologies that will operate synergistically with the crew, automating tasks of varying complexity in a dynamic, flexible manner with representations of automation state that the crew is familiar and comfortable with. In this proposal, Cybernet proposes to leverage crew members' capabilities with the design of a distributed Procedure Execution and Projection (PEP) system that focuses on supporting automation of complex procedures while ensuring crew situational awareness and anticipating future problems. Our team will leverage the recent work on the Procedure Representation Language (PRL) and the flexible, distributed and hierarchical capabilities of holonic systems. PRL is an XML encoding of the vehicle/habitat procedures in a form that both crew and automation can use, and the PEP systems' intelligent holonic modules will support crew with a range of capabilities, including automation of procedures, projection of procedures to look for problems and determine courses of action to prevent or mitigate the problems, and make sure that the crew maintain situational awareness of the procedural state. The objectives of the Phase I project are to establish critical requirements for NASA vehicle and habitat crew automation and to design and implement a prototype of the PEP system to demonstrate approach viability.
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Ceramic Composite Mechanical Fastener System for High-Temperature Structural Assemblies Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:24:27.000ZUnder Phase I, the feasibility of a novel thermal stress-free ceramic composite mechanical fastener system suitable for assembly of high-temperature composite structures was successfully demonstrated. The innovative 2-dimensional (2D) fastener design facilitates joining load-bearing hot structural assemblies and can be produced at a cost much lower than other competing designs and methods. Functional SiCf/SiCm composite fasteners having two (2) fiber reinforcement orientations of 0/90-degrees (cross-ply) and 145-degrees (bias-ply) were fabricated for characterization. Testing of the respective fasteners included both axial tension and single-lap shear. The cross-ply reinforced SiCf/SiCm fasteners exhibited axial tensile and single-lap shear strengths of 38.0 and 33.1 ksi, respectively. The bias-ply fasteners exhibited axial tensile and single-lap shear strengths of 31.3 and 29.8 ksi, respectively. Using a generalized analytical method for determining the distribution of forces and stresses in the 2D mechanical fastener developed in Phase I, optimized configurations will be designed and produced in Phase II for evaluation. The metallic subcomponents used for Phase I demonstration will be produced using a high temperature-capable material (e.g., ceramic, superalloy). Aerodynamically smooth Cf/SiCm and SiCf/SiCm composite structural lap joints will be assembled using the optimized composite fastener system for characterization. Testing of the lap joint assemblies will performed to determine the flexibility and structural efficiency of the joint as a function of off-axis loading relative to the principal axis of the fasteners. Elevated temperature testing will be performed to establish the effects of temperature on the mechanical properties of the joint.
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BOREAS HYD-03 Snow Temperature Profiles
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T07:33:56.000ZThis is a snow temperature table for HYD03. The snow temperature is given for various snow heights at various sites.
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Innovative Structural and Material Concepts for Low-Weight Low-Drag Aircraft Design Project
nasa-test-0.demo.socrata.com | Last Updated 2015-07-20T05:34:29.000ZThe overall technical objective of this multi-phase project is to develop and validate a so-called 'AAW-Process' that consists of (i) the Active Aeroelastic Wing (AAW) technology of employing multiple control surfaces in tandem for achieving loads alleviation and drag minimization using the over-determined trim capability of ZONA Euler Unsteady Solver (ZEUS), and (ii) the aeroelastic tailoring technique for optimum stiffness distribution and weight minimization while satisfying structural design constraints using ZONA's Automated STRuctural Optimization System (ASTROS). The technical objectives specific to Phase II effort are twofold: (1) Analytically design the four Subsonic Ultra Green Aircraft Research (SUGAR) wind-tunnel models that employ Distributed Multiple Control Surfaces (DMCS) and Variable Camber Continuous Trailing Edge Flap (VCCTEF) to achieve the weight and drag benefits, and (2) Fabrication of one of these four designed models to validate the AAW-process experimentally by a future wind tunnel testing. As per the first specific objective, four wind tunnel models will be designed for high speed Transonic Dynamic Tunnel (TDT) testing along with their detailed fabrication and wind tunnel testing plans. These four models are carefully chosen to incrementally demonstrate the benefits of applying AAW technology and aeroelastic tailoring technique by potential future fabrication and wind tunnel tests. As per the second specific objective, the fabricated wind tunnel model will be delivered to NASA along with its target performance improvement predicted by AAW-process for validation with a near-term wind tunnel testing. In order to ensure the safety of the wind tunnel models during the TDT testing, flutter suppression and gust load alleviation controllers will be designed for those models that are not aeroelastically tailored and have analytically displayed potential flutter instability problems.
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BOREAS HYD-03 Snow Water Equivalent: 1996
nasa-test-0.demo.socrata.com | Last Updated 2015-07-19T07:34:04.000ZABSTRACT: Contains the snow water equivalent, snow_depth, and snow density measurements made by HYD-3 with the Canadian snow sampler in 1996.