2,091 research outputs found

    Data base architecture for instrument characteristics critical to spacecraft conceptual design

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    Spacecraft designs are driven by the payloads and mission requirements that they support. Many of the payload characteristics, such as mass, power requirements, communication requirements, moving parts, and so forth directly affect the choices for the spacecraft structural configuration and its subsystem design and component selection. The conceptual design process, which translates mission requirements into early spacecraft concepts, must be tolerant of frequent changes in the payload complement and resource requirements. A computer data base was designed and implemented for the purposes of containing the payload characteristics pertinent for spacecraft conceptual design, tracking the evolution of these payloads over time, and enabling the integration of the payload data with engineering analysis programs for improving the efficiency in producing spacecraft designs. In-house tools were used for constructing the data base and for performing the actual integration with an existing program for optimizing payload mass locations on the spacecraft

    Effects of modifications to the space shuttle entry guidance and control systems

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    A nonlinear six degree of freedom entry simulation study was conducted to identify space shuttle guidance and control system software modifications which reduce the control system sensitivity to the guidance system sampling frequency. Several modifications which eliminated the control system sensitivity and associated control limit cycling were examined. The result of the modifications was a reduction in required reaction control system fuel

    Reference manual for the Langley Research Center flight simulation computing system

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    The researchers at the Langley Research Center Flight Simulation Computing System are provided with an advanced real-time digital simulation capability. This capability is controlled at the user interface level by the Real Time Simulation Supervisor. The Supervisor is a group of subprograms loaded with a simulation application program. The Supervisor provides the interface between the application program and the operating system, and coordinates input and output to and from the simulation hardware. The Supervisor also performs various utility functions as required by a simulation application program

    Development of the reentry flight dynamics simulator for evaluation of space shuttle orbiter entry systems

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    A nonlinear, six degree of freedom, digital computer simulation of a vehicle which has constant mass properties and whose attitudes are controlled by both aerodynamic surfaces and reaction control system thrusters was developed. A rotating, oblate Earth model was used to describe the gravitational forces which affect long duration Earth entry trajectories. The program is executed in a nonreal time mode or connected to a simulation cockpit to conduct piloted and autopilot studies. The program guidance and control software used by the space shuttle orbiter for its descent from approximately 121.9 km to touchdown on the runway

    Television Violence Viewing and Aggression in Females

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74709/1/j.1749-6632.1996.tb32548.x.pd

    Experimental approaches for 100 TeV gamma-ray astronomy

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    The high energy end of gamma-ray source spectra might provide important clues regarding the nature of the processes involved in gamma-ray emission. Several galactic sources with hard emission spectra extending up to more than 30TeV have already been reported. Measurements around 100TeV and above should be an important goal for the next generation of high energy gamma-ray astronomy experiments. Here we present several techniques providing the required exposure (100 km^2.h). We focus our study on three Imaging Atmospheric Cherenkov Technique (IACT) based approaches: low elevation observations, large field of view telescopes, and large telescope arrays. We comment on the advantages and disadvantages of each approach and report simulation based estimates of their energy ranges and sensitivities.Comment: 3 pages 1 figure. Proceedings of TeV particle astrophysics 2, Madison, August 2006. http://www.icecube.wisc.edu/TeV/presentations/colin_poster.pd

    Long-Term Effects of Parents\u27 Education on Children\u27s Educational and Occupational Success Mediation by Family Interactions, Child Aggression, and Teenage Aspirations

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    We examine the prediction of individuals\u27 educational and occupational success at age 48 from contextual and personal variables assessed during their middle childhood and late adolescence. We focus particularly on the predictive role of the parents\u27 educational level during middle childhood, controlling for other indices of socioeconomic status and children\u27s IQ, and the mediating roles of negative family interactions, childhood behavior, and late adolescent aspirations. Data come from the Columbia County Longitudinal Study, which began in 1960 when all 856 third graders in a semirural county in New York State were interviewed along with their parents; participants were reinterviewed at ages 19, 30, and 48 (Eron et al., 197 1; Huesmann et al., 2002). Parents\u27 educational level when the child was 8 years old significantly predicted educational and occupational success for the child 40 years later. Structural models showed that parental educational level had no direct effects on child educational level or occupational prestige at age 48 but had significant indirect effects that were independent of the other predictor variables\u27 effects. These indirect effects were mediated through age 19 educational aspirations and age 19 educational level. These results provide strong support for the unique predictive role of parental education on adult outcomes 40 years later and underscore the developmental importance of mediators of parent education effects such as late adolescent achievement and achievement-related aspirations

    Probe similarity and recognition of set membership: A parallel processing serial feature matching model

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    A model for memory scanning is proposed in which the encoded representation of a probe is compared in parallel with encoded representations of each item in the positive set. The within item matches are serial feature by feature comparisons that terminate when either a positive or negative criterion is reached. This model is shown to predict the results of a probe similarity experiment. The serial location of a similarity within an item affects negative reaction times, but the number of items in the positive set to which the probe is similar has no main effect. The model is also shown to yield predictions consonant with existing data on the relation between reaction times and set size and speed-accuracy trade offs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83371/1/1976.Huesmann&Woocher.ProbeSimilarity&Recognition.CognitPsych.pd

    Serious violent behavior and antisocial outcomes as consequences of exposure to ethnic‐political conflict and violence among Israeli and Palestinian youth

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149258/1/ab21818.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/149258/2/ab21818_am.pd
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