2,024 research outputs found
Sa-8 operational trajectory
Trajectory optimization for Saturn I /SA-8/ LAUNCH vehicle to place S- IV stage and payload in elliptical orbi
Demonstration of transparent solar array module design
This report discusses the design, development, fabrication and testing of IR transparent solar array modules. Three modules, consisting of a baseline design using back surface reflector cells, and two modules using gridded back contact, IR transparent cells, were subjected to vacuum thermal balance testing to verify analytical predictions of lower operating emperature and increased efficiency. As a result of this test program, LMSC has verified that a significant degree of IR transparency can be designed into a flexible solar array. Test data correlates with both steady state and transient thermal analysis
Learning object segmentation from video data
This memo describes the initial results of a project to create a self-supervised algorithm for learning object segmentation from video data. Developmental psychology and computational experience have demonstrated that the motion segmentation of objects is a simpler, more primitive process than the detection of object boundaries by static image cues. Therefore, motion information provides a plausible supervision signal for learning the static boundary detection task and for evaluating performance on a test set. A video camera and previously developed background subtraction algorithms can automatically produce a large database of motion-segmented images for minimal cost. The purpose of this work is to use the information in such a database to learn how to detect the object boundaries in novel images using static information, such as color, texture, and shape. This work was funded in part by the Office of Naval Research contract #N00014-00-1-0298, in part by the Singapore-MIT Alliance agreement of 11/6/98, and in part by a National Science Foundation Graduate Student Fellowship
Kinematic Orbits and the Structure of the Internal Space for Systems of Five or More Bodies
The internal space for a molecule, atom, or other n-body system can be
conveniently parameterised by 3n-9 kinematic angles and three kinematic
invariants. For a fixed set of kinematic invariants, the kinematic angles
parameterise a subspace, called a kinematic orbit, of the n-body internal
space. Building on an earlier analysis of the three- and four-body problems, we
derive the form of these kinematic orbits (that is, their topology) for the
general n-body problem. The case n=5 is studied in detail, along with the
previously studied cases n=3,4.Comment: 38 pages, submitted to J. Phys.
SINMAP 2.0 - A Stability Index Approach to Terrain Stability Hazard Mapping, User\u27s Manual
SINMAP 2.0 (Stability Index MAPping) is an ArcGIS 9.0 plug-in that implements the computation and mapping of a slope stability index based upon geographic information, primarily digital elevation data. This report describes the theoretical basis for the calculation of the stability index, describes the implementation, presents several case studies and describes use of the accompanying software. SINMAP has its theoretical basis in the infinite plane slope stability model with wetness (pore pressures) obtained from a topographically based steady state model of hydrology. Digital elevation model (DEM) methods are used to obtain the necessary input information (slope and specific catchment area). Parameters are allowed to be uncertain following uniform distributions between specified limits. These may be adjusted (and calibrated) for geographic ccalibration regionsd based upon soil, vegetation or geologic data. The methodology includes an interactive visual calibration that adjusts parameters while referring to observed landslides. The calibration involves adjustment of parameters so that the stability map ccapturesd a high proportion of observed landslides in regions with low stability index, while minimizing the extent of low stability regions and consequent alienation of terrain to regions where landslides have not been observed. This calibration is done while simultaneously referring to the stability index map, a specific catchment area and slope plot (of landslide and non landslide points) where lines distinguish the zones categorized into the different stability classes and a table giving summary statistics. The current implementation of SINMAP 2.0 is a plug-in to the ArcGIS ArcMap geographic information system (GIS) from Environmental Systems Research Institute, Inc. (ESRI). This utilizes ArcMap for its standard GIS functionality such as the input and organization of data and the presentation and output of results. SINMAP is grid based, requiring ArcGIS version 9.0 or higher
We want to get down to the nitty-gritty : The Modern Hardboiled Detective in the Novella Form
This thesis approaches the issue of the detective in the 21st century through the parodic novella form. The main body of the work is a piece of fiction about an amateur detective trying to find a solution to an imagined crime. This comes from my study of detective fiction, starting with Oedipus and ending with twentieth and twenty-first century examples, especially in the works of Thomas Pynchon and Chester Himes, where the detective loses power. The novella follows Whitney Sloat as he acts as detective in a world that can’t let go of the hardboiled traditions. He and the people around him struggle to connect with reality, pursuing a way of life that cannot exist outside of their world
Wide-bandwidth, tunable, multiple-pulse-width optical delays using slow light in cesium vapor
We demonstrate an all-optical delay line in hot cesium vapor that tunably
delays 275 ps input pulses up to 6.8 ns and 740 input ps pulses up to 59 ns
(group index of approximately 200) with little pulse distortion. The delay is
made tunable with a fast reconfiguration time (hundreds of ns) by optically
pumping out of the atomic ground states.Comment: 4 pages, 6 figure
GEM Operation in Negative Ion Drift Gas Mixtures
The first operation of GEM gas gain elements in negative ion gas mixtures is
reported. Gains up to several thousand were obtained from single-stage GEMs in
carbon disulfide vapor at low pressure, and in mixtures of carbon disulfide
with Argon and Helium, some near 1 bar total pressure.Comment: 7 pages, 3 figure
Reply to Comment by Jonathan J. Rhodes on ‘‘Modeling of the Interactions between Forest Vegetation, Disturbances, and Sediment Yields’’
Rhodes [2005] brings up some excellent points in his comments on the work of Istanbulluoglu et al. [2004]. We appreciate the opportunity to respond because it is likely that other readers will also wonder how they can apply the relatively simple analysis to important policy questions. Models necessarily reduce the complexity of the problem to make it tractable and synthesize some diverse sources of information. It may be helpful at times for readers to understand the high dimension of the complexity sacrificed in order to obtain the synthesis and the reasons for reducing the complexity in a particular manner. Rhodes [2005] comments on three things: (1) the omission of roads and landings from the analysis; (2) the implicit assumption that fire does not occur with harvesting; and (3) the overestimation of water repellency. We will respond to each of these, clarifying and elaborating on the basis for our modeling choices
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The effect of long term physical training in the development of mental toughness in recreationally active participants
This study investigated the effect of a long-term training program on the development of mental toughness (MT). Thirty (2 female and 28 male) recreationally active participants (age: 33.53±6.83years; height: 177.41±7.11cm; weight: 78.40±11.94kg; maximal oxygen uptake (VO2max): 47.00±6.48 ml.kg-1.min-1; mean±SD) undertook 6 months of training prior to completing a long-distance triathlon. Participants completed mental toughness questionnaires (MTQ48) at 0, 2, 4, and 6 months of training and 1-month post-race. Data analysis included repeated measures ANOVAs for each MTQ48 variable with consideration to faster and slower finishers. Faster and slower finishers demonstrated non-significant differences (p>0.05) on all MT criteria. There was an effect for time with overall mental toughness (OMT) improving from baseline-post race (cohens d = 0.52; p<0.01) and month 2 post race (d = 0.39; p<0.01), commitment improving from baseline-post race (d = 0.60; p<0.05) and confidence increasing from month 2 post race (d = 0.39; p<0.05). The findings indicate that long term training culminating with competitive experience favourably impacts MT
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