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Sample records for air parcels trajectories

  1. Air parcel trajectory dispersion near the tropical tropopause

    NASA Astrophysics Data System (ADS)

    Bergman, John W.; Jensen, Eric J.; Pfister, Leonhard; Bui, Thaopaul V.

    2016-04-01

    Dispersion of backward air parcel trajectories that are initially tightly grouped near the tropical tropopause is examined using three ensemble approaches: "RANWIND," in which different ensemble members use identical resolved wind fluctuations but different realizations of stochastic, multifractal simulations of unresolved winds; "PERTLOC," in which members use identical resolved wind fields but initial locations are perturbed 2° in latitude and longitude; and a multimodel ensemble ("MULTIMODEL") that uses identical initial conditions but different resolved wind fields and/or trajectory formulations. Comparisons among the approaches distinguish, to some degree, physical dispersion from that due to data uncertainty and the impacts of unresolved wind fluctuations from those of resolved variability. Dispersion rates are robust properties of trajectories near the tropical tropopause. Horizontal dispersion rates are typically ~3°/d, which is large enough to spread parcels throughout the tropics within typical tropical tropopause layer transport times (30-60 days) and underscores the importance of averaging large collections of trajectories to obtain reliable parcel source and pathway distributions. Vertical dispersion rates away from convection are ~2-3 hPa/d. Dispersion is primarily carried out by the resolved flow, and the RANWIND approach provides a plausible representation of actual trajectory dispersion rates, while PERTLOC provides a reasonable and inexpensive alternative to RANWIND. In contrast, dispersion from the MULTIMODEL calculations is important because it reflects systematic differences in resolved wind fields from different reanalysis data sets.

  2. Chemical data assimilation on air parcels trajectories for Envisat validation

    NASA Astrophysics Data System (ADS)

    Pirre, M.; Huret, N.; Taupin, F. G.; Moreau, G.; Renard, J.-B.

    2003-08-01

    Balloon chemical instruments have shown to be very useful for the validation of ENVISAT instruments GOMOS, MIPAS and SCIAMACHY. Nevertheless, it is necessary for that to obtain a very good rendezvous between balloon and satellite instruments. Such rendezvous have often been obtained during the validation campaigns, but for each balloon flight these rendezvous are obtained with only one satellite instrument. Moreover some operational problem could lead to miss the expected rendezvous. The paper presents a first attempt to use the air parcel trajectory concept to use nevertheless such balloon measurements for validation purposes. This concept is applied to the validation of the MIPAS instrument in using the flights of the instruments SALOMON on September 19, 2002 and SPIRALE on October 2, 2002 above Aire sur l'Adour. Difficulties encountered in this work and preliminary conclusions concerning MIPAS validation are given.

  3. Homogeneous and heterogeneous chemistry along air parcel trajectories

    NASA Technical Reports Server (NTRS)

    Jones, R. L.; Mckenna, D. L.; Poole, L. R.; Solomon, S.

    1990-01-01

    The study of coupled heterogeneous and homogeneous chemistry due to polar stratospheric clouds (PSC's) using Lagrangian parcel trajectories for interpretation of the Airborne Arctic Stratosphere Experiment (AASE) is discussed. This approach represents an attempt to quantitatively model the physical and chemical perturbation to stratospheric composition due to formation of PSC's using the fullest possible representation of the relevant processes. Further, the meteorological fields from the United Kingdom Meteorological office global model were used to deduce potential vorticity and inferred regions of PSC's as an input to flight planning during AASE.

  4. Uncertainty and dispersion in air parcel trajectories near the tropical tropopause

    NASA Astrophysics Data System (ADS)

    Bergman, John; Jensen, Eric; Pfister, Leonhard; Bui, Thoapaul

    2016-04-01

    The Tropical Tropopause Layer (TTL) is important as the gateway to the stratosphere for chemical constituents produced at the Earth's surface. As such, understanding the processes that transport air through the upper tropical troposphere is important for a number of current scientific issues such as the impact of stratospheric water vapor on the global radiative budget and the depletion of ozone by both anthropogenically- and naturally-produced halocarbons. Compared to the lower troposphere, transport in the TTL is relatively unaffected by turbulent motion. Consequently, Lagrangian particle models are thought to provide reasonable estimates of parcel pathways through the TTL. However, there are complications that make trajectory analyses difficult to interpret; uncertainty in the wind data used to drive these calculations and trajectory dispersion being among the most important. These issues are examined using ensembles of backward air parcel trajectories that are initially tightly grouped near the tropical tropopause using three approaches: A Monte Carlo ensemble, in which different members use identical resolved wind fluctuations but different realizations of stochastic, multi-fractal simulations of unresolved winds, perturbed initial location ensembles, in which members use identical resolved wind fields but initial locations are displaced 2° in latitude and longitude, and a multi-model ensemble that uses identical initial conditions but different resolved wind fields and/or trajectory formulations. Comparisons among the approaches distinguish, to some degree, physical dispersion from that due to data uncertainty and the impact of unresolved wind fluctuations from that of resolved variability.

  5. Tracing Trajectories of Air Parcels Transported through Spatially Resolved Horizontal Neutral Wind Fields Observed in the Thermosphere above Alaska

    NASA Astrophysics Data System (ADS)

    Dhadly, M. S.; Conde, M.

    2014-12-01

    Transport by fluid flow is a very complex problem. Any type of velocity gradient introduces distortion of the original air masses which, over time, can become extraordinarily severe. In Earth's thermosphere, it is however widely presumed that viscosity hinders both horizontal and vertical wind shears, and hence rapidly attenuates any gradients that might occur over distances shorter than synoptic scales. As a result, particle trajectories predicted by current models are often relatively simple, so that transport effects only slowly disperse and mix air masses. This means that regions of perturbed chemical composition, formed for example by intense aurora, would be expected to remain intact for many hours or even days. However, our observations show that this simple picture does not hold in practice; wind fields in the thermosphere have much more local-scale structure than predicated by models, at least in the auroral zone. These local small scale structures complicate air parcel trajectories enormously, relative to typical expectations. In Alaska, three Scanning Doppler Imaging Fabry-Perot interferometers are currently in operation. A single SDI instrument can simultaneously observe the thermospheric wind's line-of-sight component in 115 (typically) independent look directions. From these data it is possible to reconstruct time-resolved two-dimensional maps of the horizontal vector wind field, and use these to infer forward and backward air parcel trajectories over time. Tracing parcel trajectories through a given geographic location maps where they will go from there (forward tracing in time) and where they come from previously (history of parcels or tracing back in time). Results show that transport of thermospheric neutral species in the presence of the local scale wind gradients that are actually observed is far more complicated than what current models typically predict.

  6. Improving stable isotope-based reconstructions of Sierra Nevada paleotopography using insights from regional air parcel trajectories

    NASA Astrophysics Data System (ADS)

    Lechler, A.; Galewsky, J.

    2012-12-01

    The geodynamic evolution of the Sierra Nevada Mountains of the western US remains subject to debate due to the lack of consensus on the Cenozoic paleoelevation history of the range. The majority of recent studies attempting to quantify the surface uplift history of the Sierra Nevada rely on stable isotope paleoaltimetry methods that often implicitly assume that atmospheric flow interactions with topography can be simply modeled as a Rayleigh distillation process in which air mass trajectories ascend and rainout heavy isotopologues of water (18O and D) across topographic barriers relatively unimpeded. Accordingly, stable isotope paleoaltimetry studies commonly target leeward side paleo-meteoric water proxies to constrain paleotopography of the windward barrier. We present a modern (1979 - 2010) air parcel trajectory analysis using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model that shows that the fundamental assumptions of stable isotope paleoaltimetry are often violated in the Sierra Nevada region. Trajectory analysis indicates that westerly air masses are frequently orographically blocked by and redirected around the higher elevations (> 2.5 km) of the Sierra Nevada. As a result, trajectories reaching the Sierran lee commonly travel around, rather than over, the highest range elevations. These blocking and redirection effects are particularly pronounced for leeward sites that are distal (> 150 km) from the Sierran crest but are also evident in trajectory patterns for both windward and proximal leeward locations in the northern Sierra Nevada. In addition, trajectory patterns indicate that much of the Sierran lee receives a non-negligible proportion of annual precipitation from summer storm systems sourced in the subtropical Pacific Ocean and Gulf of California that have little to no interaction with Sierran topography. This trajectory analysis highlights the complexity of orographic precipitation patterns and processes in the Sierra

  7. Stratospheric ozone loss in the 1996/1997 Arctic winter: Evaluation based on multiple trajectory analysis for double-sounded air parcels by ILAS

    NASA Astrophysics Data System (ADS)

    Terao, Yukio; Sasano, Yasuhiro; Nakajima, Hideaki; Tanaka, H. L.; Yasunari, Tetsuzo

    2002-12-01

    Quantitative chemical ozone loss rates and amounts in the Arctic polar vortex for the spring of 1997 are analyzed based on ozone profile data obtained by the Improved Limb Atmospheric Spectrometer (ILAS) using an extension of the Match technique. In this study, we calculated additional multiple trajectories and set very strict criteria to overcome the weakness of the satellite sensor data (lower vertical resolution and larger sampling air mass volume) and to identify more accurately a double-sounded air mass. On the average inside the inner edge of the vortex boundary (north of about 70°N equivalent latitude), the local ozone loss rate was 50-80 ppbv/day at the maximum during late February between the levels of 450 and 500 K potential temperatures. The integrated ozone loss during February to March reached 2.0 ± 0.1 ppmv at 475-529 K levels, and the column ozone loss between 400 and 600 K during the 2 months was 96 ± 0.3 DU. Using a relative potential vorticity (rPV) scale, the vortex was divided into some rPV belts, and it was shown that the magnitude of the ozone loss increased gradually toward the vortex center from the edge. The maximum ozone loss rate of 6.0 ± 0.6 ppbv/sunlit hour near the vortex center was higher than near the vortex edge by a factor of 2-3. When we expanded the area of interest to include all the data obtained inside the vortex edge (north of about 65°N equivalent latitude), the local ozone loss rate was about 50 ppbv/day at the maximum. This value is slightly larger than that estimated by the Match analysis using ozonesondes for the same winter by ˜10 ppbv/day. Temperature histories of double-sounded air parcels indicated that the extreme ozone loss in the innermost part of the vortex was observed when the air parcel experienced temperatures below TNAT during the two soundings and had experienced temperatures near Tice in the 10 days prior to the first sounding. These facts suggest that the high ozone loss rate deep inside the vortex

  8. Comparison of stratospheric air parcel trajectories calculated from SSU and LIMS satellite data. [Stratospheric Sounding Unit/Limb Infrared Monitor of Stratosphere

    NASA Technical Reports Server (NTRS)

    Austin, J.

    1986-01-01

    Midstratospheric trajectories for February and March 1979 are calculated using geopotential analyses derived from limb infrared monitor of the stratosphere data. These trajectories are compared with the corresponding results using stratospheric sounding unit data. The trajectories are quasi-isentropic in that a radiation scheme is used to simply cross-isentrope flow. The results show that in disturbed conditions, quantitative agreement the trajectories, that is, within 25 great circle degrees (GCD) (one GCD about 110 km) may be valid for only 3 or 4 days, whereas during quiescent periods, quantitative agreement may last up to 10 days. By comparing trajectories calculated with different data some insight can be gained as to errors due to vertical resolution and horizontal resolution (due to infrequent sampling) in the analyzed geopotential height fields. For the disturbed trajectories described in this paper the horizontal resolution of the data was more important than vertical resolution; however, for the quiescent trajectories, which could be calculated accurately for a longer duration because of the absence of appreciable transients, the vertical resolution of the data was found to be more important than the horizontal resolution. It is speculated that these characteristics are also applicable to trajectories calculated during disturbed and quiescent periods in general. A review of some recently published trajectories shows that the qualitative conclusions of such works remains unaffected when the calculations are repeated using different data.

  9. On air motion trajectories in cold fronts

    NASA Technical Reports Server (NTRS)

    Reeder, Michael J.; Smith, Roger K.

    1988-01-01

    This paper examines air parcel trajectories in the two-dimensional model for a cold front by Reeder and Smith (1987). These are found to be in close agreement with trajectories deduced from analyses of summertime 'cool changes' in southeastern Australia, adding further support to the applicability of the numerical model to this kind of cold front. The favorable comparison points also to the dynamical consistency of the conceptual model for the cool change, which has evolved from the analysis of data from observational experiments.

  10. Air Parcel Residence Times within Tropical Forest Canopies and Implications for Reactive Gases

    NASA Astrophysics Data System (ADS)

    Gerken, T.; Chamecki, M.; Fuentes, J. D.

    2014-12-01

    The Amazon rainforest is the world's largest natural emitter of reactive trace gases. Due to its dense vegetation (leaf area index > 4), turbulence fluctuations are highly attenuated deep inside the canopy. However, strong coherent eddies that penetrate the upper portion of the canopy can be very effective in transporting gases. Sweeps and ejections act in the order of seconds and transport air parcels into or out of the canopy. The effects of coherent structures on the air parcel residence times and associated chemical processing of reactive gases remain largely unquantified in tropical forests. We combine canopy resolving Large-Eddy Simulation (LES) and field observations in the Brazilian Amazon to study residence times of air parcels in the rainforest as a function of canopy structure and height (h). Good agreement is obtained between simulated and observed turbulence statistics within and above the forest. Coherent structure properties obtained from quadrant analysis are also well reproduced. A Lagrangian particle tracking algorithm is used to quantify the distribution of residence times of air parcels "released" at different heights. Canopy residence times were determined from the particle trajectories. The resulting probability density function (PDF) strongly depended on the particle release height (z). For particles released in the upper canopy (at z/h=0.75) the most frequent residence times were in the order of 30s, with 50% of all particles ejected from the canopy after ~2 minutes. The mean residence time was close to 5 minutes, indicating a very skewed PDF. At z/h=0.25 the PDF was more evenly distributed with its median and mean in the order of ~10 minutes. Due to sweeps, both simulations had a non- negligible fraction of particles transported deep into the canopy, thus increasing greatly their residence times. As the reaction timescales of many biogenic volatile organic compounds (BVOC) are in the order of seconds to minutes, significant chemical

  11. Airborne Arctic Stratospheric Expedition 2: Air Parcel Trajectories

    NASA Technical Reports Server (NTRS)

    1993-01-01

    An overview of Airborne Arctic Stratospheric Expedition 2 is given. Effects of Pinatubo aerosol on stratospheric ozone at mid-latitudes, in situ measurements of ClO and ClO/HCl ratio, balloon-borne measurements of ClO, NO, and O3 in a volcanic cloud, and new observations of the NO(y)/N2O correlation in the lower stratosphere are discussed. Among other topics addressed are the following: in situ tracer correlations of methane, nitrous oxide, and ozone as observed aboard the DC-8, in situ measurements of changes in stratospheric aerosol and the N2O-aerosol relationship inside and outside of the polar vortex, measurements of halogenated organic compounds near the tropical tropopause, and airborne brightness measurements of the polar winter troposphere.

  12. Air breathing engine/rocket trajectory optimization

    NASA Technical Reports Server (NTRS)

    Smith, V. K., III

    1979-01-01

    This research has focused on improving the mathematical models of the air-breathing propulsion systems, which can be mated with the rocket engine model and incorporated in trajectory optimization codes. Improved engine simulations provided accurate representation of the complex cycles proposed for advanced launch vehicles, thereby increasing the confidence in propellant use and payload calculations. The versatile QNEP (Quick Navy Engine Program) was modified to allow treatment of advanced turboaccelerator cycles using hydrogen or hydrocarbon fuels and operating in the vehicle flow field.

  13. Stable isotope composition of waters in the Great Basin, United States 1. Air-mass trajectories

    USGS Publications Warehouse

    Friedman, I.; Harris, J.M.; Smith, G.I.; Johnson, C.A.

    2002-01-01

    Isentropic trajectories, calculated using the NOAA/Climate Monitoring and Diagnostics Laboratory's isentropic transport model, were used to determine air-parcel origins and the influence of air mass trajectories on the isotopic composition of precipitation events that occurred between October 1991 and September 1993 at Cedar City, Utah, and Winnemucca, Nevada. Examination of trajectories that trace the position of air parcels backward in time for 10 days indicated five distinct regions of water vapor origin: (1) Gulf of Alaska and North Pacific, (2) central Pacific, (3) tropical Pacific, (4) Gulf of Mexico, and (5) continental land mass. Deuterium (??D) and oxygen-18 (??18O) analyses were made of precipitation representing 99% of all Cedar City events. Similar analyses were made on precipitation representing 66% of the precipitation falling at Winnemucca during the same period. The average isotopic composition of precipitation derived from each water vapor source was determined. More than half of the precipitation that fell at both sites during the study period originated in the tropical Pacific and traveled northeast to the Great Basin; only a small proportion traversed the Sierra Nevada. The isotopic composition of precipitation is determined by air-mass origin and its track to the collection station, mechanism of droplet formation, reequilibration within clouds, and evaporation during its passage from cloud to ground. The Rayleigh distillation model can explain the changes in isotopic composition of precipitation as an air mass is cooled pseudo-adiabatically during uplift. However, the complicated processes that take place in the rapidly convecting environment of cumulonimbus and other clouds that are common in the Great Basin, especially in summer, require modification of this model because raindrops that form in the lower portion of those clouds undergo isotopic change as they are elevated to upper levels of the clouds from where they eventually drop to the

  14. Time-dependent freezing rate parcel model

    NASA Astrophysics Data System (ADS)

    Vali, G.; Snider, J. R.

    2015-02-01

    The time-dependent freezing rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period in time when the parcel remains stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time dependence is included to account for variations in updraft velocity and for the continued formation of ice particles under isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to three-fold variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.

  15. Time-dependent freezing rate parcel model

    NASA Astrophysics Data System (ADS)

    Vali, G.; Snider, J. R.

    2014-11-01

    The Time-Dependent Freezing Rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period at time with the parcel remaining stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time-dependence is included to account for variations in updraft velocity and for the continued formation of ice particles at isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to factors of about 3 variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time-dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.

  16. Maximum information trajectory for an air to air missile intercept

    NASA Astrophysics Data System (ADS)

    Larson, S. W.

    1980-12-01

    This thesis presents a method for finding the trajectory to complete an air-to-air missile intercept which maximizes information. This is accomplished by formulating a parameter optimization problem and using a penalty function-Lagrange multiplier method to solve for the optimal path. The performance index is the trace of the information matrix. This information matrix is derived using an extended Kalman filter formulation, in cartesian coordinates, which makes state estimates based only on angle measurements. The trace operation on the information matrix is used because the trace and the integration operations commute allowing a scalar performance index. Further, reduction in the functional form of the performance index is achieved by weighing the information matrix by the inverse of the measurement power spectral density. This also avoids numerical difficulties near intercept.

  17. Source areas and trajectories of nucleating air masses within and near the Carpathian Basin

    NASA Astrophysics Data System (ADS)

    Németh, Z.; Salma, I.

    2014-04-01

    Particle number size distributions were measured by differential mobility particle sizer in the diameter range of 6-1000 nm in the near-city background and city centre of Budapest continuously for two years. The city is situated in the middle part of the Carpathian Basin, which is a topographically discrete unit in the southeast Central Europe. Yearly mean nucleation frequencies and uncertainties for the near-city background and city centre were (28+6/-4) % and (27+9/-4) %, respectively. Total numbers of days with continuous and uninterrupted growth process were 43 and 31, respectively. These events and their properties were utilised to investigate if there are any specific tracks and/or separable source regions for the nucleating air masses within or near the basin. Local wind speed and direction data indicated that there seem to be differences between the nucleation and growth intervals and non-nucleation days. For further analysis, backward trajectories were generated by a simple air parcel trajectory model. Start and end time parameters of the nucleation, and end time parameter of the particle growth were derived by a standardized procedure based on examining the channel contents of the contour plots. These parameters were used to specify a segment on each air mass trajectory that is associated with the track of the nucleating air mass. The results indicated that the nucleation events happened in the continental boundary layer mostly within the Carpathian Basin but the most distant trajectories originated outside of the basin. The tracks of the nucleating air masses were predominantly associated with NW and SE geographical fields, while the source areas that could be separated were frequently situated in the NW and NE quarters. Many of them were within or close to large forested territories. The results also emphasize that the new particle formation and growth phenomenon that occurs in the region influences larger territories than the Carpathian Basin.

  18. Cloud parcel modelling of CCN activation in megacity air based on observations from Beijing and Guangzhou

    NASA Astrophysics Data System (ADS)

    Su, H.; Reutter, P.; Trentmann, J.; Rose, D.; Gunthe, S.; Simmel, M.; Nowak, A.; Wiedensohler, A.; Zhu, T.; Pöschl, U.

    2009-04-01

    The other team members are P. Achtert (3), M. Hu (4), M. Shao (4), and Y.H. Zhang (4). The activation of cloud condensation nuclei (CCN) determines the initial number of cloud droplets, and thus influences the evolution of the cloud and formation of precipitation. Characterizing the CCN activation process by parcel model studies with detailed cloud microphysics and dynamics provides useful information for parameterizing the activation process in meso-scale and global-scale models. During the CAREBEIJING 2006 campaign in Beijing and the PRIDE-PRD2006 campaign in Guangzhou, fast condensational growth of particles was frequently observed and the CCN size distribution was sometimes dominated by the growing nucleation mode (Aitken Mode) rather than by the accumulation mode. In this study we investigated the implications of the experimental findings using a cloud parcel model with detailed spectral cloud microphysics and with the ΰ-Köhler model approach for efficient and realistic description of the effective hygroscopicity and CCN activity of aerosol particles. The number of droplets formed at the cloud base was examined for a wide range of updraft velocities and aerosol particle number concentrations. Moreover, the impact of aerosol hygroscopicity, size distribution and giant CCN were also evaluated. References: Reutter, P., Trentmann, J., Su, H., Simmel M., Rose, D., Wernli, H., Andreae, M. O., and Pöschl, U.: Activation of aerosol particles as cloud condensation nuclei (CCN) under smoky and pyro-convective conditions, manuscript in preparation, 2009 Rose, D., Gunthe, S. S., Mikhailov, E., Frank, G. P., Dusek, U., Andreae, M. O., and Pöschl, U.: Calibration and measurement uncertainties of a continuous-flow cloud condensation nuclei counter (DMT-CCNC): CCN activation of ammonium sulfate and sodium chloride aerosol particles in theory and experiment, Atmos. Chem. Phys., 8, 1153-1179, 2008. Rose, D., Nowak, A., Achtert, P., Wiedensohler, A., Hu, M., Shao, M

  19. A New Wind Profiler Trajectory Tool for Air Quality Studies

    NASA Astrophysics Data System (ADS)

    White, A. B.; Senff, C. J.; Keane, A. N.; Koury, J.

    2003-12-01

    The Cooperative Institute for Research in Environmental Sciences, the NOAA Environmental Technology Laboratory (NOAA/ETL), and the Science and Technology Corporation have developed a new online tool for producing forward and backward trajectories from hourly wind profiles measured by a network of boundary-layer wind profilers. The tool is intended to aid scientists and forecasters in the planning and execution of field operations during the 2004 Northeast North Atlantic Air Quality Study. This study will involve an international consortium of agencies and will include upwards of a dozen of research aircraft and the NOAA research vessel Ronald H. Brown. The purpose of this talk is to demonstrate the tool and collect feedback from scientific investigators, which we will use to modify the tool before the 2004 field study. In addition, we will present preliminary results from the 2002 New England Air Quality Study that demonstrate the value of using continuous profiler observations instead of numerical model initialization fields to calculate trajectories for the meteorologically complex coastal zone of New England. The trajectory tool uses the horizontal wind profiles measured by the profiler network that are collected in near-real time and archived at NOAA/ETL's facility in Boulder, Colorado. The vertical velocities are not used because of large uncertainty in the profiler's vertical velocity measurement. To calculate hourly trajectory positions, the horizontal winds are interpolated in space using an inverse distance squared weighting. Users may request altitude ranges for the trajectories as well as start and end times and trajectory starting/end points. Trajectories are plotted on a two dimensional map background and are color coded by their respective altitude range.

  20. Phase 1 Environmental Baseline Survey Parcels E2, F, and I, Military Housing Areas, Nellis Air Force Base, Nevada

    DTIC Science & Technology

    2011-09-01

    thistle (Salsola sp.), a noxious weed, commonly occurs in 3.2 disturbed areas. There are no threatened, endangered or rare species located on...located on the parcel. Miscellaneous Structures – A wall exists on Parcel I. The wall is seven feet tall and marks the eastern boundary of the

  1. Environmental Baseline Survey Parcel E2, F, and I, Military Housing Areas Nellis Air Force Base, Nevada. Phase 1

    DTIC Science & Technology

    2011-09-01

    ephedra (Ephedra sp.). Russian thistle (Salsola sp.), a noxious weed, commonly occurs in 3.2 disturbed areas. There are no threatened, endangered...poles or transformers are located on the parcel. Miscellaneous Structures – A wall exists on Parcel I. The wall is seven feet tall and marks the

  2. Trajectory Specification for High-Capacity Air Traffic Control

    NASA Technical Reports Server (NTRS)

    Paielli, Russell A.

    2004-01-01

    In the current air traffic management system, the fundamental limitation on airspace capacity is the cognitive ability of human air traffic controllers to maintain safe separation with high reliability. The doubling or tripling of airspace capacity that will be needed over the next couple of decades will require that tactical separation be at least partially automated. Standardized conflict-free four-dimensional trajectory assignment will be needed to accomplish that objective. A trajectory specification format based on the Extensible Markup Language is proposed for that purpose. This format can be used to downlink a trajectory request, which can then be checked on the ground for conflicts and approved or modified, if necessary, then uplinked as the assigned trajectory. The horizontal path is specified as a series of geodetic waypoints connected by great circles, and the great-circle segments are connected by turns of specified radius. Vertical profiles for climb and descent are specified as low-order polynomial functions of along-track position, which is itself specified as a function of time. Flight technical error tolerances in the along-track, cross-track, and vertical axes define a bounding space around the reference trajectory, and conformance will guarantee the required separation for a period of time known as the conflict time horizon. An important safety benefit of this regimen is that the traffic will be able to fly free of conflicts for at least several minutes even if all ground systems and the entire communication infrastructure fail. Periodic updates in the along-track axis will adjust for errors in the predicted along-track winds.

  3. Trajectory Specification for Automation of Terminal Air Traffic Control

    NASA Technical Reports Server (NTRS)

    Paielli, Russell A.

    2016-01-01

    "Trajectory specification" is the explicit bounding and control of aircraft tra- jectories such that the position at each point in time is constrained to a precisely defined volume of space. The bounding space is defined by cross-track, along-track, and vertical tolerances relative to a reference trajectory that specifies position as a function of time. The tolerances are dynamic and will be based on the aircraft nav- igation capabilities and the current traffic situation. A standard language will be developed to represent these specifications and to communicate them by datalink. Assuming conformance, trajectory specification can guarantee safe separation for an arbitrary period of time even in the event of an air traffic control (ATC) sys- tem or datalink failure, hence it can help to achieve the high level of safety and reliability needed for ATC automation. As a more proactive form of ATC, it can also maximize airspace capacity and reduce the reliance on tactical backup systems during normal operation. It applies to both enroute airspace and the terminal area around airports, but this paper focuses on arrival spacing in the terminal area and presents ATC algorithms and software for achieving a specified delay of runway arrival time.

  4. Photochemical trajectory modelling studies of the 1987 Antarctic spring vortex

    NASA Technical Reports Server (NTRS)

    Austin, J.; Jones, R. L.; Mckenna, D. S.

    1988-01-01

    Simulations of Antarctic ozone photochemistry performed using a photochemical model integrated along air parcel trajectories are described. This type of model has a major advantage at high latitudes of being able to simulate correctly the complex interaction between photolysis and temperature fields, which, because of the polar night cannot be represented accurately in a zonally averaged framework. Isentropic air parcel trajectories were computed using Meteorological Office global model analyses and forecast fields from positions along the ER-2 flight paths during the Airborne Antarctic Ozone Experiment in Austral Spring 1987. A photochemical model is integrated along these trajectories using the aircraft observations to initialize constituent concentrations. The model includes additional reactions of the ClO dimer and also bromine reactions, which are thought to play a significant role in Antarctica. The model also includes heterogeneous reactions which are invoked when the air parcel passes through a polar stratospheric cloud (PSC). The existence of a PSC is determined throughout the course of the model integration from the parcel temperature and the saturated vapour pressure of water over an assumed H2O/HNO3 mixture. The air parcel temperature is used to determine the saturated vapor pressure of HNO3 over the same mixture. Mixing ratios which exceed saturation result in condensation of the excess in the model and hence lead to a reduction of the amount of gas phase NO2 available for chemical reaction.

  5. Phase 1 Environmental Baseline Survey Nellis Terrace Housing Area, Parcel E-1, Nellis Air Force Base, Nevada

    DTIC Science & Technology

    2010-03-01

    12 3.17 RADON ............................................................................................................ 12 3.18 LEAD...subject property. 3.17 RADON See Section 3.17, pages 3-17 and 3-18 of the 2003 EBS for a description of radon with respect to Parcel E-1...which is a subpart of the Nellis Terrace Housing Area described therein. According to record searches, interviews, and a site reconnaissance, no radon

  6. Effects of modeling errors on trajectory predictions in air traffic control automation

    NASA Technical Reports Server (NTRS)

    Jackson, Michael R. C.; Zhao, Yiyuan; Slattery, Rhonda

    1996-01-01

    Air traffic control automation synthesizes aircraft trajectories for the generation of advisories. Trajectory computation employs models of aircraft performances and weather conditions. In contrast, actual trajectories are flown in real aircraft under actual conditions. Since synthetic trajectories are used in landing scheduling and conflict probing, it is very important to understand the differences between computed trajectories and actual trajectories. This paper examines the effects of aircraft modeling errors on the accuracy of trajectory predictions in air traffic control automation. Three-dimensional point-mass aircraft equations of motion are assumed to be able to generate actual aircraft flight paths. Modeling errors are described as uncertain parameters or uncertain input functions. Pilot or autopilot feedback actions are expressed as equality constraints to satisfy control objectives. A typical trajectory is defined by a series of flight segments with different control objectives for each flight segment and conditions that define segment transitions. A constrained linearization approach is used to analyze trajectory differences caused by various modeling errors by developing a linear time varying system that describes the trajectory errors, with expressions to transfer the trajectory errors across moving segment transitions. A numerical example is presented for a complete commercial aircraft descent trajectory consisting of several flight segments.

  7. Conflict-free trajectory planning for air traffic control automation

    NASA Technical Reports Server (NTRS)

    Slattery, Rhonda; Green, Steve

    1994-01-01

    As the traffic demand continues to grow within the National Airspace System (NAS), the need for long-range planning (30 minutes plus) of arrival traffic increases greatly. Research into air traffic control (ATC) automation at ARC has led to the development of the Center-TRACON Automation System (CTAS). CTAS determines optimum landing schedules for arrival traffic and assists controllers in meeting those schedules safely and efficiently. One crucial element in the development of CTAS is the capability to perform long-range (20 minutes) and short-range (5 minutes) conflict prediction and resolution once landing schedules are determined. The determination of conflict-free trajectories within the Center airspace is particularly difficult because of large variations in speed and altitude. The paper describes the current design and implementation of the conflict prediction and resolution tools used to generate CTAS advisories in Center airspace. Conflict criteria (separation requirements) are defined and the process of separation prediction is described. The major portion of the paper will describe the current implementation of CTAS conflict resolution algorithms in terms of the degrees of freedom for resolutions as well as resolution search techniques. The tools described in this paper have been implemented in a research system designed to rapidly develop and evaluate prototype concepts and will form the basis for an operational ATC automation system.

  8. An Efficient Algorithm for Commercial Aircraft Trajectory Optimization in the Air Traffic System

    NASA Astrophysics Data System (ADS)

    Devulapalli, Raghuveer

    A discrete search strategy is presented to determine optimal aircraft trajectories which can be unconstrained or regulated to follow current Air Traffic Control (ATC) procedures. The heuristic based Astar (A*) search algorithm has been selected for its efficiency and its inherent ability to handle numerous constraints as a discrete method. A point-mass aircraft model is assumed to accurately simulate commercial aircraft dynamics for the provided trajectories. The two dimensional space and the states of aircraft have been divided into discrete pieces. To show the effectiveness of the algorithm, two-dimensional vertical and horizontal profile are simulated. Simulation results compare optimal trajectories that range from unconstrained to those that completely adhere to strict ATC procedures. Those trajectories following ATC procedures follow a segmented flight pattern where each segment follows specified objectives, terminating when certain criteria has been met. Trajectories are optimized for a combination of time and fuel with an emphasis on reducing fuel consumption.

  9. The Impact of Trajectory Prediction Uncertainty on Air Traffic Controller Performance and Acceptability

    NASA Technical Reports Server (NTRS)

    Mercer, Joey S.; Bienert, Nancy; Gomez, Ashley; Hunt, Sarah; Kraut, Joshua; Martin, Lynne; Morey, Susan; Green, Steven M.; Prevot, Thomas; Wu, Minghong G.

    2013-01-01

    A Human-In-The-Loop air traffic control simulation investigated the impact of uncertainties in trajectory predictions on NextGen Trajectory-Based Operations concepts, seeking to understand when the automation would become unacceptable to controllers or when performance targets could no longer be met. Retired air traffic controllers staffed two en route transition sectors, delivering arrival traffic to the northwest corner-post of Atlanta approach control under time-based metering operations. Using trajectory-based decision-support tools, the participants worked the traffic under varying levels of wind forecast error and aircraft performance model error, impacting the ground automations ability to make accurate predictions. Results suggest that the controllers were able to maintain high levels of performance, despite even the highest levels of trajectory prediction errors.

  10. A demonstration and evaluation of trajectory mapping

    SciTech Connect

    Morris, G.A.

    1994-09-01

    Problem of creating synoptic maps from asynoptically gathered data has prompted the development of a number schemes, the most notable being the Kalman filter, Salby-Fourier technique, and constituent reconstruction. This thesis presents a new technique, called trajectory mapping, which employs a simple model of air parcel motion to create synoptic maps from asynoptically gathered data. Four sources of trajectory mapping errors were analyzed; results showed that (1) the computational error is negligible; (2) measurement uncertainties can result in errors which grow with time scales of a week; (3) isentropic approximations lead to errors characterized by time scales of a week; and (4) wind field inaccuracies can cause significant errors in individual parcel trajectories in a matter of hours. All the studies, however, indicated that while individual trajectory errors can grow rapidly, constituent distributions, such as on trajectory maps, are much more robust, maintaining a high level of accuracy for periods on the order of several weeks. This technique was successfully applied to a variety of problems:(1) dynamical wave- breaking events; (2) satellite data validation for both instrument accuracy and precision; and (3) accuracy of meteorological wind fields. Such demonstrations imply that trajectory mapping will become an important tool in answering questions of global change, particularly the issue of ozone depletion.

  11. Separating the Air Quality Impact of a Major Highway and Nearby Sources by Nonparametric Trajectory Analysis

    EPA Science Inventory

    Nonparametric Trajectory Analysis (NTA), a receptor-oriented model, was used to assess the impact of local sources of air pollution at monitoring sites located adjacent to highway I-15 in Las Vegas, NV. Measurements of black carbon, carbon monoxide, nitrogen oxides, and sulfur di...

  12. A fast ascent trajectory optimization method for hypersonic air-breathing vehicles

    NASA Astrophysics Data System (ADS)

    Murillo, Oscar J., Jr.

    The objective of this dissertation is to investigate a fast and reliable method to generate three-dimensional optimal ascent trajectories for hypersonic air-breathing vehicles. The problem is notoriously difficult because of the strong nonlinear coupling amongst aerodynamics, propulsion, vehicle attitude and trajectory state. As such an algorithm matures, the ultimate goal is to realize optimal closed-loop ascent guidance for hypersonic air-breathing vehicles. The problem is formulated as a fuel-optimal control problem. The corresponding necessary conditions are given. It is shown how the original problem of search for the optimal control commands can be reduced to a univariate root-finding problem at each point along the trajectory. A finite difference scheme is used to numerically solve the associated two-point-boundary-value problem. Evaluation of the approach is done through open-loop solutions and closed-loop simulations. The results show promising potential of the proposed approach as a rapid trajectory optimization tool for the class of hypersonic air-breathing vehicles.

  13. Spatial variability of hailfalls in France: an analysis of air mass retro-trajectories

    NASA Astrophysics Data System (ADS)

    Hermida, Lucía; Merino, Andrés; Sánchez, José Luis; Berthet, Claude; Dessens, Jean; López, Laura; Fernández-González, Sergio; Gascón, Estíbaliz; García-Ortega, Eduardo

    2014-05-01

    Hail is the main meteorological risk in south-west France, with the strongest hailfalls being concentrated in just a few days. Specifically, this phenomenon occurs most often and with the greatest severity in the Midi-Pyrénées area. Previous studies have revealed the high spatial variability of hailfall in this part of France, even leading to different characteristics being recorded on hailpads that were relatively close together. For this reason, an analysis of the air mass trajectories was carried out at ground level and at altitude, which subsequently led to the formation of the hail recorded by these hailpads. It is already known that in the study zone, the trajectories of the storms usually stretch for long distances and are oriented towards the east, leading to hailstones with diameters in excess of 3 cm, and without any change in direction above 3 km. We analysed different days with hail precipitation where there was at least one stone with a diameter of 3 cm or larger. Using the simulations from these days, an analysis of the backward trajectories of the air masses was carried out. We used the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) to determine the origin of the air masses, and tracked them toward each of the hailpads that were hit during the day studied. The height of the final points was the height of the impacted hailpads. Similarly, the backward trajectories for different heights were also established. Finally, the results show how storms that affect neighbouring hailpads come from very different air masses; and provide a deeper understanding of the high variability that affects the characteristics of hailfalls. Acknowledgements The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2. This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22).

  14. A Near-Term Concept for Trajectory Based Operations with Air/Ground Data Link Communication

    NASA Technical Reports Server (NTRS)

    McNally, David; Mueller, Eric; Thipphavong, David; Paielli, Russell; Cheng, Jinn-Hwei; Lee, Chuhan; Sahlman, Scott; Walton, Joe

    2010-01-01

    An operating concept and required system components for trajectory-based operations with air/ground data link for today's en route and transition airspace is proposed. Controllers are fully responsible for separation as they are today, and no new aircraft equipage is required. Trajectory automation computes integrated solutions to problems like metering, weather avoidance, traffic conflicts and the desire to find and fly more time/fuel efficient flight trajectories. A common ground-based system supports all levels of aircraft equipage and performance including those equipped and not equipped for data link. User interface functions for the radar controller's display make trajectory-based clearance advisories easy to visualize, modify if necessary, and implement. Laboratory simulations (without human operators) were conducted to test integrated operation of selected system components with uncertainty modeling. Results are based on 102 hours of Fort Worth Center traffic recordings involving over 37,000 individual flights. The presence of uncertainty had a marginal effect (5%) on minimum-delay conflict resolution performance, and windfavorable routes had no effect on detection and resolution metrics. Flight plan amendments and clearances were substantially reduced compared to today s operations. Top-of-descent prediction errors are the largest cause of failure indicating that better descent predictions are needed to reliably achieve fuel-efficient descent profiles in medium to heavy traffic. Improved conflict detections for climbing flights could enable substantially more continuous climbs to cruise altitude. Unlike today s Conflict Alert, tactical automation must alert when an altitude amendment is entered, but before the aircraft starts the maneuver. In every other failure case tactical automation prevented losses of separation. A real-time prototype trajectory trajectory-automation system is running now and could be made ready for operational testing at an en route

  15. Trajectory Assessment and Modification Tools for Next Generation Air Traffic Management Operations

    NASA Technical Reports Server (NTRS)

    Brasil, Connie; Lee, Paul; Mainini, Matthew; Lee, Homola; Lee, Hwasoo; Prevot, Thomas; Smith, Nancy

    2011-01-01

    This paper reviews three Next Generation Air Transportation System (NextGen) based high fidelity air traffic control human-in-the-loop (HITL) simulations, with a focus on the expected requirement of enhanced automated trajectory assessment and modification tools to support future air traffic flow management (ATFM) planning positions. The simulations were conducted at the National Aeronautics and Space Administration (NASA) Ames Research Centers Airspace Operations Laboratory (AOL) in 2009 and 2010. The test airspace for all three simulations assumed the mid-term NextGenEn-Route high altitude environment utilizing high altitude sectors from the Kansas City and Memphis Air Route Traffic Control Centers. Trajectory assessment, modification and coordination decision support tools were developed at the AOL in order to perform future ATFM tasks. Overall tool usage results and user acceptability ratings were collected across three areas of NextGen operatoins to evaluate the tools. In addition to the usefulness and usability feedback, feasibility issues, benefits, and future requirements were also addressed. Overall, the tool sets were rated very useful and usable, and many elements of the tools received high scores and were used frequently and successfully. Tool utilization results in all three HITLs showed both user and system benefits including better airspace throughput, reduced controller workload, and highly effective communication protocols in both full Data Comm and mixed-equipage environments.

  16. Seasonal variations and sources study by way of back trajectories and ANOVA for ambient air pollutants (particulates and metallic elements) within a mixed area at Longjing, central Taiwan: 1-year observation.

    PubMed

    Fang, Guor-Cheng; Lo, Chaur-Tsuen; Zhuang, Yuan-Jie; Cho, Meng-Hsien; Huang, Chao-Yang; Xiao, You-Fu; Tsai, Kai-Hsiang

    2017-02-01

    This study measured the concentrations of particulates and metallic elements in ambient air by using PS-1 sampler (TSP) at Longjing area. And this study focuses on the collection of ambient air particulates, metallic elements, particulate-bound mercury Hg(p), concentrations. In addition, the sources of ambient pollutants by way of back trajectory analysis are found. Moreover, test mean concentration variance differences for metallic elements (PM, Hg(p), Mn, Fe, Zn, Cr, Cu, and Pb) among the four seasons (spring, summer, autumn and winter) through ANOVA are calculated. The result indicates that the average highest particulate concentration occurred in winter season, and the order was winter > spring > autumn > summer, and the mostly highest average metallic element (Mn, Fe, Zn, Cr, Cu, Pb) concentrations occurred in autumn. Moreover, the mostly average lowest metallic element concentrations occurred in summer. In addition, the above results of backward trajectories that the major particulate pollutants parcel mainly come from northeastern Taiwan. Moreover, when comparing the results of the first half year to that of the second half year, the they indicated that all metallic elements displayed significant differences in concentrations except those of Hg(p), Mn, Fe, Zn. Finally, metallic element Hg(p) is the only one which showed no significant concentration difference from either seasonal variations or half-year observations.

  17. Impact of maritime air mass trajectories on the Western European coast urban aerosol.

    PubMed

    Almeida, S M; Silva, A I; Freitas, M C; Dzung, H M; Caseiro, A; Pio, C A

    2013-01-01

    Lisbon is the largest urban area in the Western European coast. Due to this geographical position the Atlantic Ocean serves as an important source of particles and plays an important role in many atmospheric processes. The main objectives of this study were to (1) perform a chemical characterization of particulate matter (PM2.5) sampled in Lisbon, (2) identify the main sources of particles, (3) determine PM contribution to this urban area, and (4) assess the impact of maritime air mass trajectories on concentration and composition of respirable PM sampled in Lisbon. During 2007, PM2.5 was collected on a daily basis in the center of Lisbon with a Partisol sampler. The exposed Teflon filters were measured by gravimetry and cut into two parts: one for analysis by instrumental neutron activation analysis (INAA) and the other by ion chromatography (IC). Principal component analysis (PCA) and multilinear regression analysis (MLRA) were used to identify possible sources of PM2.5 and determine mass contribution. Five main groups of sources were identified: secondary aerosols, traffic, calcium, soil, and sea. Four-day backtracking trajectories ending in Lisbon at the starting sampling time were calculated using the HYSPLIT model. Results showed that maritime transport scenarios were frequent. These episodes were characterized by a significant decrease of anthropogenic aerosol concentrations and exerted a significant role on air quality in this urban area.

  18. Separating the air quality impact of a major highway and nearby sources by nonparametric trajectory analysis.

    PubMed

    Henry, Ronald C; Vette, Alan; Norris, Gary; Vedantham, Ram; Kimbrough, Sue; Shores, Richard C

    2011-12-15

    Nonparametric Trajectory Analysis (NTA), a receptor-oriented model, was used to assess the impact of local sources of air pollution at monitoring sites located adjacent to highway I-15 in Las Vegas, NV. Measurements of black carbon, carbon monoxide, nitrogen oxides, and sulfur dioxide concentrations were collected from December 2008 to December 2009. The purpose of the study was to determine the impact of the highway at three downwind monitoring stations using an upwind station to measure background concentrations. NTA was used to precisely determine the contribution of the highway to the average concentrations measured at the monitoring stations accounting for the spatially heterogeneous contributions of other local urban sources. NTA uses short time average concentrations, 5 min in this case, and constructed local back-trajectories from similarly short time average wind speed and direction to locate and quantify contributions from local source regions. Averaged over an entire year, the decrease of concentrations with distance from the highway was found to be consistent with previous studies. For this study, the NTA model is shown to be a reliable approach to quantify the impact of the highway on local air quality in an urban area with other local sources.

  19. On the Origin of Polar Vortex Air

    NASA Technical Reports Server (NTRS)

    Rosenfield, J. E.; Schoeberl, M. R.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    The existence of the multi-year HALOE CH4 data set, together with some comparisons of forward with back trajectory calculations which we have carried out, has motivated us to reexamine the question of polar vortex descent. Three-dimensional diabatic trajectory calculations have been carried out for the seven month fall to spring period in both the northern hemisphere (NH) and southern hemisphere (SH) polar stratosphere for the years 1992-1999. These computations are compared to fixed descent computations where the parcels were fixed at their latitude-longitude locations and allowed to descend without circulating. The forward trajectory computed descent is always less than the fixed descent due to horizontal parcel motions and variations in heating rates with latitude and longitude. Although the forward calculations estimate the maximum amount of descent that can occur, they do not necessarily indicate the actual origin of springtime vortex air. This is because more equator-ward air can be entrained within the vortex during its formation. To examine the origin of the springtime vortex air, the trajectory model was run backward for seven months from spring to fall. The back trajectories show a complex distribution of parcels in which one population originates in the upper stratosphere and mesosphere and experiences considerable descent in the polar regions, while the remaining parcels originate at lower altitudes of the middle and lower stratosphere and are mixed into the polar regions during vortex formation without experiencing as much vertical transport. The amount of descent experienced by the first population shows little variability from year to year, while the computed descent and mixing of the remaining parcels show considerable interannual variability due to the varying polar meteorology. Because of this complex parcel distribution it is not meaningful to speak of a net amount of descent experienced over the entire winter period. Since the back trajectories

  20. FORMAL UNCERTAINTY ANALYSIS OF A LAGRANGIAN PHOTOCHEMICAL AIR POLLUTION MODEL. (R824792)

    EPA Science Inventory

    This study applied Monte Carlo analysis with Latin
    hypercube sampling to evaluate the effects of uncertainty
    in air parcel trajectory paths, emissions, rate constants,
    deposition affinities, mixing heights, and atmospheric stability
    on predictions from a vertically...

  1. Complexity analysis of the Next Gen Air Traffic Management System: trajectory based operations.

    PubMed

    Lyons, Rhonda

    2012-01-01

    According to Federal Aviation Administration traffic predictions currently our Air Traffic Management (ATM) system is operating at 150 percent capacity; forecasting that within the next two decades, the traffic with increase to a staggering 250 percent [17]. This will require a major redesign of our system. Today's ATM system is complex. It is designed to safely, economically, and efficiently provide air traffic services through the cost-effective provision of facilities and seamless services in collaboration with multiple agents however, contrary the vision, the system is loosely integrated and is suffering tremendously from antiquated equipment and saturated airways. The new Next Generation (Next Gen) ATM system is designed to transform the current system into an agile, robust and responsive set of operations that are designed to safely manage the growing needs of the projected increasingly complex, diverse set of air transportation system users and massive projected worldwide traffic rates. This new revolutionary technology-centric system is dynamically complex and is much more sophisticated than it's soon to be predecessor. ATM system failures could yield large scale catastrophic consequences as it is a safety critical system. This work will attempt to describe complexity and the complex nature of the NextGen ATM system and Trajectory Based Operational. Complex human factors interactions within Next Gen will be analyzed using a proposed dual experimental approach designed to identify hazards, gaps and elicit emergent hazards that would not be visible if conducted in isolation. Suggestions will be made along with a proposal for future human factors research in the TBO safety critical Next Gen environment.

  2. Air-breathing hypersonic vehicle guidance and control studies; An integrated trajectory/control analysis methodology: Phase 1

    NASA Technical Reports Server (NTRS)

    Hattis, Philip D.; Malchow, Harvey L.

    1991-01-01

    A tool which generates optimal trajectory/control histories in an integrated manner is generically adapted to the treatment of single-stage-to-orbit air-breathing hypersonic vehicles. The methodology is implemented as a two point boundary value problem solution technique. Its use permits an assessment of an entire near-minimum-fuel trajectory and desired control strategy from takeoff to orbit while satisfying physically derived inequality constraints and while achieving efficient propulsive mode phasing. A simpler analysis strategy that partitions the trajectory into several boundary condition matched segments is also included to construct preliminary trajectory and control history representations with less computational burden than is required for the overall flight profile assessment. A demonstration was accomplished using a tabulated example (winged-cone accelerator) vehicle model that is combined with a newly developed multidimensional cubic spline data smoothing routine. A constrained near-fuel-optimal trajectory, imposing a dynamic pressure limit of 1000 psf, was developed from horizontal takeoff to 20,000 ft/sec relative air speed while aiming for a polar orbit. Previously unspecified propulsive discontinuities were located. Flight regimes demanding rapid attitude changes were identified, dictating control effector and closed-loop controller authority was ascertained after evaluating effector use for vehicle trim. Also, inadequacies in vehicle model representations and specific subsystem models with insufficient fidelity were determined based on unusual control characteristics and/or excessive sensitivity to uncertainty.

  3. Assessment of potential long-range transport of particulate air pollution using trajectory modeling and monitoring data

    NASA Astrophysics Data System (ADS)

    Pongkiatkul, Prapat; Kim Oanh, Nguyen Thi

    2007-07-01

    Quantification of the long-range transport (LRT) contribution to ambient air pollution levels at a location is a challenging task and is normally done with a high uncertainty. In the lack of accurate emission data over the large regional domain for dispersion modeling, this study attempts to use both trajectory analysis and monitoring data to assess the potential contribution of LRT to particulate air pollution (PM) in the Bangkok Metropolitan Region (BMR). The 10-day backward trajectories of air masses arriving at BMR from January 2002 to December 2004 were determined using Hybrid Single-Particle Langrangian Integrated Trajectory model version 4 (HYSPLIT4) and were categorized by k-means clustering into 6 clusters. Subsequently, PM levels in the BMR associated with each air mass cluster during this period were analyzed. Clusters 1 and 6 were observed with the highest and 2nd highest average PM 10 and PM 2.5 levels in the BMR, respectively, which commonly have a longer air mass pathway over populated South East Asia (SEA). The third highest PM levels were associated with air masses from the east (clusters 2 and 5), which enter the BMR via the Gulf of Thailand without passing the SEA regions. The other two clusters (3 and 4) are characterized with a long pathway of air masses over the Indian Ocean and the lowest PM levels. High PM days, which are defined based on the spatial coverage of high PM levels in the BMR, were identified and analyzed for the possibility of long-range transport contribution of PM. The potential source contribution function (PSCF) and air mass trajectories show that on high PM day, the air masses commonly originated and passed over populated regions before arriving at the BMR, which suggests a possible LRT contribution. Considerations are made for surface ozone, SO 42-/SO 2 and average SO 2, PM 2.5/PM 10, and weekday-weekend traffic emission within each air mass trajectory cluster to reveal the possible LRT contribution.

  4. Cluster analysis of the impact of air back-trajectories on aerosol optical properties at Hornsund, Spitsbergen

    NASA Astrophysics Data System (ADS)

    Rozwadowska, A.; Zieliński, T.; Petelski, T.; Sobolewski, P.

    2010-02-01

    In this paper, spectra of aerosol optical thickness from the AERONET (AErosol RObotic NETwork) station at Hornsund in the southern part of Spitsbergen were employed to study the impact of air mass history on aerosol optical thickness for wavelength λ=500 nm - AOT(500) - and the Ångström exponent. Backward trajectories computed, using the NOAA HYSPLIT model, were used to trace air history. It was found that in spring, the changes in AOT values over the Hornsund station were strongly influenced by air mass trajectories 8 days or longer in duration, arriving both in the free troposphere and at an altitude of 1 km above sea level. Nevertheless, free tropospheric advection was dominant. AOT variability in summer was best explained by the local direction and speed of advection (1-day trajectories) and was dominated by the effectiveness of cleansing processes. During the ASTAR 2007 campaign, the aerosols near Hornsund displayed low AOT values ranging from 0.06 to 0.09, which is lower than the mean AOT(500) for spring seasons from 2005 to 2007 (0.110±0.007; mean ± standard deviation of mean). 9 April 2007 with AOT(500)=0.147 was exceptional. The back-trajectories belonged to clusters with low and average cluster mean AOT. Apart from the maximum AOT of 9 April 2007, the observed AOT values were close to or lower than the means for the clusters to which they belonged.

  5. Tracking hazardous air pollutants from a refinery fire by applying on-line and off-line air monitoring and back trajectory modeling.

    PubMed

    Shie, Ruei-Hao; Chan, Chang-Chuan

    2013-10-15

    The air monitors used by most regulatory authorities are designed to track the daily emissions of conventional pollutants and are not well suited for measuring hazardous air pollutants that are released from accidents such as refinery fires. By applying a wide variety of air-monitoring systems, including on-line Fourier transform infrared spectroscopy, gas chromatography with a flame ionization detector, and off-line gas chromatography-mass spectrometry for measuring hazardous air pollutants during and after a fire at a petrochemical complex in central Taiwan on May 12, 2011, we were able to detect significantly higher levels of combustion-related gaseous and particulate pollutants, refinery-related hydrocarbons, and chlorinated hydrocarbons, such as 1,2-dichloroethane, vinyl chloride monomer, and dichloromethane, inside the complex and 10 km downwind from the fire than those measured during the normal operation periods. Both back trajectories and dispersion models further confirmed that high levels of hazardous air pollutants in the neighboring communities were carried by air mass flown from the 22 plants that were shut down by the fire. This study demonstrates that hazardous air pollutants from industrial accidents can successfully be identified and traced back to their emission sources by applying a timely and comprehensive air-monitoring campaign and back trajectory air flow models.

  6. Trajectory analysis of acid deposition data from the new jersey pine barrens

    NASA Astrophysics Data System (ADS)

    Budd, William W.

    This research provides an example of the application of a simple method for evaluating regional interrelationships using air parcel trajectory analysis. An assessment of trajectories associated with storms affecting McDonald's Branch watershed (39°50'N, 74°30'W) is presented. A simple classification system is used to examine regional contributions of acid precursors. The results of the work suggest that major regional sources of acid precursor emissions dominated precipitation acidity for the Pine Barrens region from 1978 to 1981. An incremental approach to acid precipitation policy is suggested.

  7. Trajectory Hunting: Analysis of UARS Measurements showing Rapid Chlorine Activation

    NASA Technical Reports Server (NTRS)

    Danilin, M.Y.; Santee, M. L.; Rodriquez, J. M.; Ko, M. K. W.; Mergenthaler, J. M.; Kumer, J. B.; Tabazadeh, A.

    1998-01-01

    Trajectory hunting (i.e., a technique to find air parcels sampled at least twice over the course of a few days) is applied to analyze Upper Atmosphere Research Satellite (UARS) measurements in conjunction with the AER photochemical box model. In this study, we investigate rapid chlorine activation in the Arctic lower stratosphere on 29 Dec 1992 associated with a polar stratospheric cloud (PSC) event. Six air parcels that have been sampled twice were followed along 5-day trajectories at the 465 K (approximately 46 mb) and 585 K (approximately 22 mb) levels. A detailed sensitivity study with the AER. photochemical box model along these trajectories leads to the following conclusions for the episode considered: (1) model results are in better agreement with UARS measurements at these levels if the UKMO temperature is decreased by at least 1-2 K; (2) the NAT (nitric acid trihydrate) PSC formation scheme produces results in better agreement with observations than the STS (supercooled ternary solution) scheme; (3) the model can explain the UARS measurements at 585 K, but under-estimates the ClO abundance at 465 K, suggesting some inconsistency between the UARS measurements at this level.

  8. Trajectory Hunting: Analysis of UARS Measurements Showing Rapid Chlorine Activation

    NASA Technical Reports Server (NTRS)

    Danilin, M. Y.; Santee, M. L.; Rodriquez, J. M.; Ko, M. K. W.; Mergenthaler, J. M.; Kumer, J. B.; Tabazadeh, A.

    1998-01-01

    Trajectory hunting (i.e., a technique to find air parcels sampled at least twice over the course of a few days) is applied to analyze Upper Atmosphere Research Satellite (UARS) measurements in conjunction with the AER photochemical box model. In this study, we investigate rapid chlorine activation in the Arctic lower stratosphere on 29 Dec. 1992 associated with a polar stratospheric cloud (PSC) event. Six air parcels that have been sampled twice were followed along 5-day trajectories at the 465 K (approx. 46 mb) and 585 K (approxi. 22 mb) levels. A detailed sensitivity study with the AER photochemical box model along these trajectories leads to the following conclusions for the episode considered: 1) model results are in better agreement with UARS measurements at these levels if the U.K. Meteorological Office (UKMO) temperature is decreased by at least 1-2 K; 2) the NAT (nitric acid trihydrate) PSC formation scheme produces results in better agreement with observations than the STS (supercooled ternary solution) scheme; 3) the model can explain the UARS measurements at 585 K, but under-estimates the ClO abundance at 465 K, suggesting some inconsistency between the UARS measurements at this level.

  9. Uncertainty analysis and robust trajectory linearization control of a flexible air-breathing hypersonic vehicle

    NASA Astrophysics Data System (ADS)

    Pu, Zhiqiang; Tan, Xiangmin; Fan, Guoliang; Yi, Jianqiang

    2014-08-01

    Flexible air-breathing hypersonic vehicles feature significant uncertainties which pose huge challenges to robust controller designs. In this paper, four major categories of uncertainties are analyzed, that is, uncertainties associated with flexible effects, aerodynamic parameter variations, external environmental disturbances, and control-oriented modeling errors. A uniform nonlinear uncertainty model is explored for the first three uncertainties which lumps all uncertainties together and consequently is beneficial for controller synthesis. The fourth uncertainty is additionally considered in stability analysis. Based on these analyses, the starting point of the control design is to decompose the vehicle dynamics into five functional subsystems. Then a robust trajectory linearization control (TLC) scheme consisting of five robust subsystem controllers is proposed. In each subsystem controller, TLC is combined with the extended state observer (ESO) technique for uncertainty compensation. The stability of the overall closed-loop system with the four aforementioned uncertainties and additional singular perturbations is analyzed. Particularly, the stability of nonlinear ESO is also discussed from a Liénard system perspective. At last, simulations demonstrate the great control performance and the uncertainty rejection ability of the robust scheme.

  10. Using Lidar, in-situ measurements and Trajectory Analysis to observe air pollution in Beijing, 2014

    NASA Astrophysics Data System (ADS)

    Chen, Zhenyi; Liu, Wenqing; Liu, Jianguo; Zhang, Tianshu; Dong, Yunsheng

    2016-06-01

    We present combined Mie lidar, ozone lidar and wide-range particle spectrometer observations that were carried out in Beijing, north China during two periods—one haze period before the Asia-Pacific Economic Cooperation (APEC) meeting and one moderate pollution period during the meeting in 2014. High extinction coefficient, moderate ozone concentration and variable particle number concentration were obtained throughout the first haze observation period. The mean extinction coefficients in the two pollution periods were 0.52 km-1 and 0.23 km-1, respectively, at 532 nm. The ozone concentration during the first haze phase was more various with higher average value of 49 ppb compared to that in the second pollution observations (32 ppb). The comparison of aerosols and ozone in different heights indicate different pollution sources and complicated ozone process of generation and disappearance. The four-day back trajectories from a HYSPLIT model indicate that the air masses in the lower boundary layer were advected from the densely populated south regions of China and the long pollution transportation passing through northern China.

  11. A Comparison of Two Methods for Initiating Air Mass Back Trajectories

    NASA Astrophysics Data System (ADS)

    Putman, A.; Posmentier, E. S.; Faiia, A. M.; Sonder, L. J.; Feng, X.

    2014-12-01

    Lagrangian air mass tracking programs in back cast mode are a powerful tool for estimating the water vapor source of precipitation events. The altitudes above the precipitation site where particle's back trajectories begin influences the source estimation. We assume that precipitation comes from water vapor in condensing regions of the air column, so particles are placed in proportion to an estimated condensation profile. We compare two methods for estimating where condensation occurs and the resulting evaporation sites for 63 events at Barrow, AK. The first method (M1) uses measurements from a 35 GHz vertically resolved cloud radar (MMCR), and algorithms developed by Zhao and Garrett1 to calculate precipitation rate. The second method (M2) uses the Global Data Assimilation System reanalysis data in a lofting model. We assess how accurately M2, developed for global coverage, will perform in absence of direct cloud observations. Results from the two methods are statistically similar. The mean particle height estimated by M2 is, on average, 695 m (s.d. = 1800 m) higher than M1. The corresponding average vapor source estimated by M2 is 1.5⁰ (s.d. = 5.4⁰) south of M1. In addition, vapor sources for M2 relative to M1 have ocean surface temperatures averaging 1.1⁰C (s.d. = 3.5⁰C) warmer, and reported ocean surface relative humidities 0.31% (s.d. = 6.1%) drier. All biases except the latter are statistically significant (p = 0.02 for each). Results were skewed by events where M2 estimated very high altitudes of condensation. When M2 produced an average particle height less than 5000 m (89% of events), M2 estimated mean particle heights 76 m (s.d. = 741 m) higher than M1, corresponding to a vapor source 0.54⁰ (s.d. = 4.2⁰) south of M1. The ocean surface at the vapor source was an average of 0.35⁰C (s.d. = 2.35⁰C) warmer and ocean surface relative humidities were 0.02% (s.d. = 5.5%) wetter. None of the biases was statistically significant. If the vapor source

  12. Unsupervised fetal cortical surface parcellation

    PubMed Central

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-01-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features. PMID:27413248

  13. Unsupervised fetal cortical surface parcellation

    NASA Astrophysics Data System (ADS)

    Dahdouh, Sonia; Limperopoulos, Catherine

    2016-03-01

    At the core of many neuro-imaging studies, atlas-based brain parcellations are used for example to study normal brain evolution across the lifespan. These atlases rely on the assumption that the same anatomical features are present on all subjects to be studied and that these features are stable enough to allow meaningful comparisons between different brain surfaces and structures These methods, however, often fail when applied to fetal MRI data, due to the lack of consistent anatomical features present across gestation. This paper presents a novel surface-based fetal cortical parcellation framework which attempts to circumvent the lack of consistent anatomical features by proposing a brain parcellation scheme that is based solely on learned geometrical features. A mesh signature incorporating both extrinsic and intrinsic geometrical features is proposed and used in a clustering scheme to define a parcellation of the fetal brain. This parcellation is then learned using a Random Forest (RF) based learning approach and then further refined in an alpha-expansion graph-cut scheme. Based on the votes obtained by the RF inference procedure, a probability map is computed and used as a data term in the graph-cut procedure. The smoothness term is defined by learning a transition matrix based on the dihedral angles of the faces. Qualitative and quantitative results on a cohort of both healthy and high-risk fetuses are presented. Both visual and quantitative assessments show good results demonstrating a reliable method for fetal brain data and the possibility of obtaining a parcellation of the fetal cortical surfaces using only geometrical features.

  14. 78 FR 63521 - Product Change-Parcel Select & Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-24

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select & Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service TM... Parcel Select & Parcel Return Service Contract 5 to Competitive Product List. Documents are available...

  15. 77 FR 37078 - Product Change-Parcel Select and Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-20

    ... [Federal Register Volume 77, Number 119 (Wednesday, June 20, 2012)] [Notices] [Page 37078] [FR Doc No: 2012-14936] POSTAL SERVICE Product Change--Parcel Select and Parcel Return Service Negotiated... of the United States Postal Service to Add Parcel Select & Parcel Return Service Contract 4...

  16. Parcellating connectivity in spatial maps

    PubMed Central

    Beck, Diane M.; Fei-Fei, Li

    2015-01-01

    A common goal in biological sciences is to model a complex web of connections using a small number of interacting units. We present a general approach for dividing up elements in a spatial map based on their connectivity properties, allowing for the discovery of local regions underlying large-scale connectivity matrices. Our method is specifically designed to respect spatial layout and identify locally-connected clusters, corresponding to plausible coherent units such as strings of adjacent DNA base pairs, subregions of the brain, animal communities, or geographic ecosystems. Instead of using approximate greedy clustering, our nonparametric Bayesian model infers a precise parcellation using collapsed Gibbs sampling. We utilize an infinite clustering prior that intrinsically incorporates spatial constraints, allowing the model to search directly in the space of spatially-coherent parcellations. After showing results on synthetic datasets, we apply our method to both functional and structural connectivity data from the human brain. We find that our parcellation is substantially more effective than previous approaches at summarizing the brain’s connectivity structure using a small number of clusters, produces better generalization to individual subject data, and reveals functional parcels related to known retinotopic maps in visual cortex. Additionally, we demonstrate the generality of our method by applying the same model to human migration data within the United States. This analysis reveals that migration behavior is generally influenced by state borders, but also identifies regional communities which cut across state lines. Our parcellation approach has a wide range of potential applications in understanding the spatial structure of complex biological networks. PMID:25737822

  17. The Origins of Air Parcels Uplifted in a Two Dimensional Gravity Wave in the Tropical Upper Troposphere During the NASA Stratosphere Troposphere Exchange Project (STEP)

    NASA Technical Reports Server (NTRS)

    Selkirk, Henry B.; Pfister, Leonhard; Chan, K. Roland; Kritz, Mark; Kelly, Ken

    1989-01-01

    During January and February 1987, as part of the Stratosphere-Troposphere Exchange Project, the NASA ER-2 made 11 flights from Darwin, Australia to investigate dehydration mechanisms in the vicinity of the tropical tropopause. After the monsoon onset in the second week of January, steady easterly flow of 15-25 ms (exp -1) was established in the upper troposphere and lower stratosphere over northern Australia and adjacent seas. Penetrating into this regime were elements of the monsoon convection such as overshooting convective turrets and extensive anvils including cyclone cloud shields. In cases of the latter, the resulting flow obstructions tended to produce mesoscale gravity waves. In several instances the ER- 2 meteorological and trace constituent measurements provide a detailed description of the structure of these gravity waves. Among these was STEP Flight 6, 22-23 January. It is of particular interest to STEP because of the close proximity of ice-laden and dehydrated air on the same isentropic surfaces. Convective events inject large amounts of ice into the upper troposphere and lower stratosphere which may not be completely removed by local precipitation processes. In the present instance, a gravity wave for removed from the source region appears to induce relativity rapid upward motion in the ice-laden air and subsequent dessication. Potential mechanisms for such a localized removal process are under investigation.

  18. Air-breathing hypersonic vehicle guidance and control studies: An integrated trajectory/control analysis methodology, phase 2

    NASA Technical Reports Server (NTRS)

    Hattis, Philip D.; Malchow, Harvey L.

    1992-01-01

    An integrated trajectory/control analysis algorithm has been used to generate trajectories and desired control strategies for two different hypersonic air-breathing vehicle models and orbit targets. Both models used cubic spline curve fit tabulated winged-cone accelerator vehicle representations. Near-fuel-optimal, horizontal takeoff trajectories, imposing a dynamic pressure limit of 1000 psf, were developed. The first model analysis case involved a polar orbit and included the dynamic effects of using elevons to maintain longitudinal trim. Analysis results indicated problems with the adequacy of the propulsion model and highlighted dynamic pressure/altitude instabilities when using vehicle angle of attack as a control variable. Also, the magnitude of computed elevon deflections to maintain trim suggested a need for alternative pitch moment management strategies. The second analysis case was reformulated to use vehicle pitch attitude relative to the local vertical as the control variable. A new, more realistic, air-breathing propulsion model was incorporated. Pitch trim calculations were dropped and an equatorial orbit was specified. Changes in flight characteristics due to the new propulsion model have been identified. Flight regimes demanding rapid attitude changes have been noted. Also, some issues that would affect design of closed-loop controllers were ascertained.

  19. Hydraulic Hybrid and Conventional Parcel Delivery Vehicles' Measured Laboratory Fuel Economy on Targeted Drive Cycles

    SciTech Connect

    Lammert, M. P.; Burton, J.; Sindler, P.; Duran, A.

    2014-10-01

    This research project compares laboratory-measured fuel economy of a medium-duty diesel powered hydraulic hybrid vehicle drivetrain to both a conventional diesel drivetrain and a conventional gasoline drivetrain in a typical commercial parcel delivery application. Vehicles in this study included a model year 2012 Freightliner P100H hybrid compared to a 2012 conventional gasoline P100 and a 2012 conventional diesel parcel delivery van of similar specifications. Drive cycle analysis of 484 days of hybrid parcel delivery van commercial operation from multiple vehicles was used to select three standard laboratory drive cycles as well as to create a custom representative cycle. These four cycles encompass and bracket the range of real world in-use data observed in Baltimore United Parcel Service operations. The NY Composite cycle, the City Suburban Heavy Vehicle Cycle cycle, and the California Air Resources Board Heavy Heavy-Duty Diesel Truck (HHDDT) cycle as well as a custom Baltimore parcel delivery cycle were tested at the National Renewable Energy Laboratory's Renewable Fuels and Lubricants Laboratory. Fuel consumption was measured and analyzed for all three vehicles. Vehicle laboratory results are compared on the basis of fuel economy. The hydraulic hybrid parcel delivery van demonstrated 19%-52% better fuel economy than the conventional diesel parcel delivery van and 30%-56% better fuel economy than the conventional gasoline parcel delivery van on cycles other than the highway-oriented HHDDT cycle.

  20. Collision Dynamics of a Rough Deformable Sphere and its Subsequent Trajectory in Air at High Reynolds Number.

    NASA Astrophysics Data System (ADS)

    Cirino, Matthew Joseph

    We begin by modeling the collision between two macroscopic bodies, where one of the bodies, a sphere, is treated as a damped, linear spring. Predictions of the sphere's resultant speed, spin rate, and angle above the horizontal are made, and are compared to the results of experiments we performed on golf balls. In the general case, the ball first slides, then rolls upward along the striking surface. Toward the end of the impact, the ball may even slip on the hitting surface, similar to the action of tires on a rapidly accelerating car. Inertial forces which arise in a rotating coordinate system play a major role in this analysis. After the collision, the final values of the spin rate, speed, and angle above the horizontal are used to provide initial conditions for the trajectory of the ball in air. In order to precisely calculate the trajectory, the effects of drag due to air resistance and lift due to spin (the "Magnus Effect") must be taken into account. The trajectory also depends upon the drag and lift coefficients of the ball, which are, in general, functions of the velocity, spin, Reynolds number, and roughness of the ball. For the case in which the coefficients are considered constant, the numerical results for the trajectories compare favorably to an analytic method we developed that ignores terms of second order in the ratio of horizontal to vertical velocity components. For the non-constant coefficient case, the decay of the ball's spin rate is incorporated for the first time. It is assumed to be proportional to the product of the spin and the speed of the ball. A physical model that explains this correspondence is discussed, and evidence supporting the model is provided by experimental data.

  1. Evaluation of some significant issues affecting trajectory and control management for air-breathing hypersonic vehicles

    NASA Technical Reports Server (NTRS)

    Hattis, Philip D.; Malchow, Harvey L.

    1992-01-01

    Horizontal takeoff airbreathing-propulsion launch vehicles require near-optimal guidance and control which takes into account performance sensitivities to atmospheric characteristics while satisfying physically-derived operational constraints. A generic trajectory/control analysis tool that deepens insight into these considerations has been applied to two versions of a winged-cone vehicle model. Information that is critical to the design and trajectory of these vehicles is derived, and several unusual characteristics of the airbreathing propulsion model are shown to have potentially substantial effects on vehicle dynamics.

  2. Frozen Waves following arbitrary spiral and snake-like trajectories in air

    NASA Astrophysics Data System (ADS)

    Dorrah, Ahmed H.; Zamboni-Rached, Michel; Mojahedi, Mo

    2017-01-01

    We present, in theory and experiment, a class of non-diffracting and self-healing optical beams whose central spot can be designed to follow off-axis curved trajectories. The intensity of the generated waveform can traverse a spiral path with the possibility of reversing its handedness and changing its longitudinal intensity pattern with propagation, on demand. The central spot can also be designed to evolve from a straight to a curved snake-like trajectory and vice versa. Such flexible level of control can be useful for many applications in atomic guiding, optical trapping, and material processing.

  3. Thunderstorm-environment interactions determined with three-dimensional trajectories

    NASA Technical Reports Server (NTRS)

    Wilson, G. S.

    1980-01-01

    Diagnostically determined three dimensional trajectories were used to reveal some of the scale interaction processes that occur between convective storms and their environment. Data from NASA's fourth Atmospheric Variability Experiment are analyzed. Two intense squall lines and numerous reports of severe weather occurred during the period. Convective storm systems with good temporal and spatial continuity are shown to be related to the development and movement of short wave circulation systems aloft that propagate eastward within a zonal mid tropospheric wind pattern. These short wave systems are found to produce the potential instability and dynamic triggering needed for thunderstorm formation. The environmental flow patterns, relative to convective storm systems, are shown to produce large upward air parcel movements in excess of 50 mb/3h in the immediate vicinity of the storms. The air undergoing strong lifting originates as potentially unstable low level air traveling into the storm environment from southern and southwestern directions. The thermo and hydrodynamical processes that lead to changes in atmospheric structure before, during, and after convective storm formation are described using total time derivatives of pressure or net vertical displacement, potential temperature, and vector wind calculated by following air parcels.

  4. Noncontact ultrasonic transportation of small objects in a circular trajectory in air by flexural vibrations of a circular disc.

    PubMed

    Koyama, Daisuke; Nakamura, Kentaro

    2010-06-01

    We have developed a noncontact ultrasonic technique for transporting small objects with a linear trajectory over long distances using a bending vibrating plate and a reflector. In this paper, noncontact transportation of small particles around a circular trajectory was investigated. A circular aluminum plate with a piezoelectric ring was employed as a vibrating plate. On the basis of finite element analysis (FEA) calculations, the electrodes of the piezoelectric ring were divided into 24 pieces to generate a flexural vibration mode with one nodal circle and four nodal lines at the resonance frequency of 47.8 kHz. A circular plate having the same dimensions as the vibrating plate was installed parallel to the vibrator. It was used as a reflector to generate an acoustic standing wave in the air between the two plates. The acoustic field between the vibrating plate and reflector was calculated by FEA and the distribution of the acoustic radiation force acting on a small rigid particle was calculated to predict the position of the trapped particle. Using a prototype of the vibrating plate, polystyrene particles with diameters of several millimeters could be trapped at regular intervals along the horizontal nodal line of the standing wave. The sound pressure distribution between the vibrating plate and reflector was measured by a fiber optic probe and the experimental and calculated results showed good agreement. By switching the driving conditions of the divided electrodes in the circumferential direction, the nodal lines of the vibrating plate could be rotated and the trapped particle could be manipulated with a circular trajectory in air.

  5. Automated Cooperative Trajectories for a More Efficient and Responsive Air Transportation System

    NASA Technical Reports Server (NTRS)

    Hanson, Curt

    2015-01-01

    The NASA Automated Cooperative Trajectories project is developing a prototype avionics system that enables multi-vehicle cooperative control by integrating 1090 MHz ES ADS-B digital communications with onboard autopilot systems. This cooperative control capability will enable meta-aircraft operations for enhanced airspace utilization, as well as improved vehicle efficiency through wake surfing. This briefing describes the objectives and approach to a flight evaluation of this system planned for 2016.

  6. 77 FR 28409 - Product Change-Parcel Select & Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select & Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service\\TM... Postal Regulatory Commission a Request of the United States Postal Service to Add Parcel Select &...

  7. Identifying tropospheric baseline air masses at Mauna Loa Observatory between 2004 and 2010 using Radon-222 and back trajectories

    NASA Astrophysics Data System (ADS)

    Chambers, Scott D.; Zahorowski, Wlodek; Williams, Alastair G.; Crawford, Jagoda; Griffiths, Alan D.

    2013-01-01

    We use 7 years of hourly radon observations at Mauna Loa Observatory (MLO), together with 10-day back trajectories, to identify baseline air masses at the station. The amplitude of the annual MLO radon cycle, based on monthly means, was 98 mBq m-3 (39 -137 mBq m-3), with maximum values in February (90th percentile 330 mBq m-3) and minimum values in August (10th percentile 8.1 mBq m-3). The composite diurnal radon cycle (amplitude 49 mBq m-3) is discussed with reference to the influences of local flow features affecting the site, and a 3-hour diurnal sampling window (0730-1030 HST) is proposed for observing the least terrestrially influenced tropospheric air masses. A set of 763 baseline events is selected, using the proposed sampling window together with trajectory information, and presented along with measured radon concentrations as a supplement. This data set represents a resource for the selection of baseline events at MLO for use with a range of trace species. A reduced set of 196 "deep baseline" events occurring in the July-September window is also presented and discussed. The distribution (10th/50th/90th percentile) of radon in deep-baseline events (8.7/29.2/66.1 mBq m-3) was considerably lower than that for the overall set of 763 baseline events (12.3/40.8/104.1 mBq m-3). Results from a simple budget calculation, using sonde-derived mixing depths and literature-based estimates of oceanic radon flux and radon concentrations in the marine boundary layer, indicate that the main source of residual radon in the lower troposphere under baseline conditions at MLO is downward mixing from aged terrestrial air masses in the upper troposphere.

  8. The Stochastic Parcel Model: A deterministic parameterization of stochastically entraining convection

    NASA Astrophysics Data System (ADS)

    Romps, David M.

    2016-03-01

    Convective entrainment is a process that is poorly represented in existing convective parameterizations. By many estimates, convective entrainment is the leading source of error in global climate models. As a potential remedy, an Eulerian implementation of the Stochastic Parcel Model (SPM) is presented here as a convective parameterization that treats entrainment in a physically realistic and computationally efficient way. Drawing on evidence that convecting clouds comprise air parcels subject to Poisson-process entrainment events, the SPM calculates the deterministic limit of an infinite number of such parcels. For computational efficiency, the SPM groups parcels at each height by their purity, which is a measure of their total entrainment up to that height. This reduces the calculation of convective fluxes to a sequence of matrix multiplications. The SPM is implemented in a single-column model and compared with a large-eddy simulation of deep convection.

  9. Origin of atmospheric aerosols at the Pierre Auger Observatory using studies of air mass trajectories in South America

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antičić, T.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bardenet, R.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Foerster, N.; Fox, B. D.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gemmeke, H.; Ghia, P. L.; Giammarchi, M.; Giller, M.; Gitto, J.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kadija, K.; Kambeitz, O.; Kampert, K. H.; Karhan, P.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Nožka, L.; Oehlschläger, J.; Olinto, A.; Oliveira, M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Pontz, M.; Porcelli, A.; Preda, T.; Privitera, P.; Prouza, M.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rivera, H.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Martino, J.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Rouillé-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schröder, F. G.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Straub, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Šuša, T.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Tapia, A.; Tartare, M.; Taşcău, O.; Thao, N. T.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Tridapalli, D. B.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Whelan, B. J.; Widom, A.; Wieczorek, G.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Curci, G.

    2014-11-01

    The Pierre Auger Observatory is making significant contributions towards understanding the nature and origin of ultra-high energy cosmic rays. One of its main challenges is the monitoring of the atmosphere, both in terms of its state variables and its optical properties. The aim of this work is to analyse aerosol optical depth τa(z) values measured from 2004 to 2012 at the observatory, which is located in a remote and relatively unstudied area of Pampa Amarilla, Argentina. The aerosol optical depth is in average quite low - annual mean τa(3.5 km) ∼ 0.04 - and shows a seasonal trend with a winter minimum - τa(3.5 km) ∼ 0.03 -, and a summer maximum - τa(3.5 km) ∼ 0.06 -, and an unexpected increase from August to September - τa(3.5 km) ∼ 0.055. We computed backward trajectories for the years 2005 to 2012 to interpret the air mass origin. Winter nights with low aerosol concentrations show air masses originating from the Pacific Ocean. Average concentrations are affected by continental sources (wind-blown dust and urban pollution), whilst the peak observed in September and October could be linked to biomass burning in the northern part of Argentina or air pollution coming from surrounding urban areas.

  10. Using synoptic classification and trajectory analysis to assess air quality during the winter heating period in Ürümqi, China

    NASA Astrophysics Data System (ADS)

    Wang, Lili; Wang, Yuesi; Sun, Yang; Li, Yuanyuan

    2012-03-01

    Synoptic patterns identified by an automated procedure employing principal-component analysis and a two-stage cluster analysis, and backward trajectory analysis clustered by the HYSPLIT4.9 model were used to examine air quality patterns over Ürümqi, China, one of the most heavily polluted cities in the world. Six synoptic patterns representing different atmospheric circulation patterns and air-mass characteristics were classified during the winter heating periods from 2001 to 2008, and seven trajectory clusters representing different paths of air masses arriving at Ürümqi were calculated during the winter heating periods from 2005 to 2008. Then air quality was evaluated using these two approaches, and significant variations were found across both synoptic patterns and trajectory clusters. The heaviest air-pollution episodes occurred when Ürümqi was either in an extremely cold, strong anticyclone or at the front of a migrating cyclone. Both conditions were characterized by with light winds, cold, wet surface air, and relatively dry upper air. Ürümqi was predominately influenced by air masses from the southwest and from local areas. Air pollution index (API) levels were highest for air masses originating from the southwest with a longer path or for the local area, because of transport from semi-desert/desert regions by strong winds and because of local heavy pollution emissions, respectively. The interactions between these two analytical approaches showed that poor diffusion conditions, together with local circulation, enhanced air pollution, besides, regional air-mass transport caused by strong winds contributed to serious air quality under relatively good diffusion conditions.

  11. Seasonal variability of tritium and ion concentrations in rain at Kumamoto, Japan and back-trajectory analysis of air mass

    SciTech Connect

    Momoshima, N.; Sugihara, S.; Toyoshima, T.; Nagao, Y.; Takahashi, M.; Nakamura, Y.

    2008-07-15

    Tritium and major ion concentrations in rain were analyzed in Kumamoto (Japan)) between 2001 and 2006 to examine present tritium concentration and seasonal variation. The average tritium concentration was 0.36 {+-} 0.19 Bq/L (n=104) and higher tritium concentrations were observed in spring than the other seasons. Among the ions, non-sea-salt (nss) SO{sub 4}{sup 2}'- showed higher concentration in winter while other ions did not show marked increase in winter. Based on the back-trajectory analyses of air masses, the increase in tritium concentrations in spring arises from downward movement of naturally produced tritium from stratosphere to troposphere, while the increase of the nss-SO{sub 4}{sup 2-} concentrations in winter is due to long range transport of pollutants from China to Japan. (authors)

  12. Trajectory Hunting: A Case Study of Rapid Chlorine Activation in December 1992 as Seen by UARS

    NASA Technical Reports Server (NTRS)

    Danilin, M. Y.; Santee, M. L.; Rodriguez, J. M.; Ko, M. K. W.; Mergenthaler, J. M.; Kumer, J. B.; Tabazadeh, A.; Livesey, N. J.

    2000-01-01

    Trajectory hunting (i.e., a technique to find air parcels sampled at least twice over the course of a few days) is applied to analyze Upper Atmosphere Research Satellite (UARS) measurements in conjunction with the Atmospheric and Environmental Research, Inc. (AER) photochemical box model. As a case study, we investigate rapid chlorine activation in the Arctic lower stratosphere on December 29, 1992 associated with a polar stratospheric cloud (PSC) event. Eleven air parcels that have been sampled several times along five-day trajectories at the 465 K (approx. 46 hPa), 520 K (approx. 31 hPa), and 585 K (approx. 22 hPa) levels were investigated. For the first time, the latest versions of the Cryogenic Limb Array Etalon Spectrometer (CLAES, version 9) and Microwave Limb Sounder (MLS, version 5) data sets are analyzed, and their consistency is assessed. A detailed sensitivity study with the AER photochemical box model along these trajectories leads to the conclusion that for the December 24-29, 1992 episode: (1) the individual CLAES ClONO2 and MLS ClO measurements are self-consistent within their uncertainties; and (2) most of the time, UARS measurements of ClO, ClONO2, HNO3, and aerosol extinction at 780 cm(exp -1) agree within the range of their uncertainties with the model calculations. It appears that the HNO3 and aerosol extinction measurements for four parcels at 520 K look more supportive for the nitric acid trihydrate (NAT) scheme, However, the uncertainties in the individual UARS measurements and UK Meteorological Office temperature do not allow a definite discrimination between the NAT and supercooled ternary solution (STS) PSC schemes for this chlorine activation episode in December 1992.

  13. Trajectory Hunting: A Case Study of Rapid Chlorine Activation in December 1992 as Seen by UARS

    NASA Technical Reports Server (NTRS)

    Danilin, M. Y.; Santee, M. L.; Rodriquez, J. M.; Ko, M. K. W.; Mergenthaler, J. M.; Kumer, J. B.; Tabazadeh, A.; Livesey

    2000-01-01

    Trajectory hunting (i.e., a technique to find air parcels sampled at least twice over the course of a few days) is applied to analyze Upper Atmosphere Research Satellite (UARS) measurements in conjunction with the Atmospheric and Environmental Research, Inc. (AER) photochemical box model. As a case study, we investigate rapid chlorine activation in the Arctic lower stratosphere on December 29, 1992 associated with a polar stratospheric cloud (PSC) event. Eleven air parcels that have been sampled several times along 5-day trajectories at the 465 K (approx. 46 hPa), 520 K (approx. 31 hPa), and 585 K (approx. 22 hPa) levels were investigated. For the first time, the latest versions of the Cryogenic Limb Array Etalon Spectrometer (CLAES, version 9) and Microwave Limb Sounder (MLS, version 5) data sets are analyzed, and their consistency is assessed. A detailed sensitivity study with the AER photochemical box model along these trajectories leads to the conclusion that for the December 24-29, 1992 episode (1) the individual CLAES version 9 ClONO2 and MLS version 5 ClO measurements are self-consistent within their uncertainties; and (2) most of the time, UARS measurements of ClO, ClONO2, HNO3, and aerosol extinction at 780 cm (exp -1) agree within the range of their uncertainties with the model calculations. It appears that the HNO3 and aerosol extinction measurements for four parcels at 520 K look more supportive for the nitric acid trihydrate (NAT) scheme. However, the uncertainties in the individual UARS measurements and U.K. Meteorological Office temperature do not allow a definite discrimination between the NAT and supercooled ternary solution (STS) PSC schemes for this chlorine activation episode in December 1992.

  14. 76 FR 16460 - Parcel Select Price and Classification Changes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-23

    ... Parcel Select Price and Classification Changes AGENCY: Postal Regulatory Commission. ACTION: Notice... changes affecting Parcel Select. The Postal Service seeks to implement new prices for Parcel Select for... implement new prices for Parcel Select for forwarding and return to sender. The fee would be the...

  15. Recent trends of persistent organic pollutants in air in central Europe - Air monitoring in combination with air mass trajectory statistics as a tool to study the effectivity of regional chemical policy

    NASA Astrophysics Data System (ADS)

    Dvorská, A.; Lammel, G.; Holoubek, I.

    We use air mass back trajectory analysis of persistent organic pollutant (POP) levels monitored at a regional background site, Košetice, Czech Republic, as a tool to study the effectiveness of emission reduction measures taken in the last decade in the region. The representativity of the chosen trajectory starting height for air sampling near ground was ensured by excluding trajectories starting at time of inversions lower than their starting height. As the relevant pollutant sources are exclusively located in the atmospheric boundary layer, trajectory segments above this layer were also excluded from the analysis. We used a linear time weight to account for the influence of dispersion and deposition on trace components abundances and to quantify the ground source loading, a continuous measure for the influence of surface emissions. Hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), polychlorinated biphenyls (PCBs), DDT, and two time periods, the years 1997-1999 and 2004-2006, were studied. The pollutant levels transported to Košetice decreased for all substances except HCB. Except for lindane seasonal emissions were insignificant. Increasing emissions of HCB were at least partly linked to the 2002 floods in the Danube basin. Major emissions of 1997-1999 which decreased significantly were in France (lindane), western Poland, Hungary and northern ex-Yugoslavia (technical HCH), and the Czech Republic (DDT). Emissions remaining in 2004-2006 include HCB and DDT in the northern Czech Republic, HCB and PCBs in Germany. Besides changes in emission strength meteorological factors influence the level of transported pollutant concentrations. The prevailing air flow pattern limits the geographic coverage of this analysis to central Europe and parts of western Europe. However, no POP monitoring stations exist in areas suitable for a possible extension of the study area.

  16. Back-trajectory Analyses of Water Vapor in Northern Mongolia

    NASA Astrophysics Data System (ADS)

    Koike, Y.; Asanuma, J.

    2012-12-01

    Knowledge of precipitation sources is indispensable for prediction of extreme events as droughts and flood [Dirmeyer and Brubaker, 1999]. In this paper, the transport pathways of water vapor that precipitates in northern Mongolia were identified using back-trajectory analyses in order to find out factors causing such events in arid/semi-arid area. First, a back-trajectory model of atmospheric water vapor was developed. An air parcel is placed on an isentropic plane over the target site at each time of precipitation. Then, back trajectories was calculated with a kinematic method following the implicit technique [Merrill et al., 1986; Merrill, 1989]. Each of the air parcels was tagged with the precipitation time and the altitude, and then tracked back in time for 5 days on the isentropic surface. Japanese 25-year Reanalysis/JMA Climate Data Assimilation System (JRA-25/JCDAS) of Japan Meteorological Agency [Onogi et al., 2007] was used for 3D field of meteorological variables for the calculation. As a validation, the model was compared with two others, namely, Meteorological Data Explorer of the Center for Global Environmental Reserch (METEX/CGER) [Zeng et al., 2003], and the trajectory model of the National Institute of Polar Research (NIPR) [Tomikawa and Sato, 2005]. The comparison found that model results are fairly robust within 5 days from the computational start, i.e., the end of the trajectory, regardless of different datasets and different schemes employed in these models. Then, the back-trajectory model was applied to the observed precipitation at the target site, a surface station in northern Mongolia called Kherlenbayan-Ulaan(KBU), where highly accurate and temporarily dense precipitation measurements are available. Back trajectory lines were calculated for each of the observed precipitation during the warm season of the years 2003 to 2009, on the isentropic surfaces of 300K, 310K and 320K where the highest value of water vapor is observed. The results show

  17. On the motion of air through the stratospheric polar vortex

    NASA Technical Reports Server (NTRS)

    Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.

    1994-01-01

    Trajectory calculations using horizontal winds from the U.K. Meteorological Office data assimilation system and vertical velocities from a radiation calculation are used to simulate the three-dimensional motion of air through the stratospheric polar vortex for Northern Hemisphere (NH) and Southern Hemisphere (SH) winters since the launch of the Upper Atmosphere Research Satellite (UARS). Throughout the winter, air from the upper stratosphere moves poleward and descends into the middle stratosphere. In the SH lower to middle stratosphere, strongest descent occurs near the edge of the polar vortex, with that edge defined by mixing characteristics. The NH shows a similar pattern in late winter, but in early winter strongest descent is near the center of the vortex, except when wave activity is particularly strong. Strong barriers to latitudinal mixing exist above about 420 K throughout the winter. Below this, the polar night jet is weak in early winter, so air descending below that level mixes between polar and middle latitudes. In late winter, parcels descend less and the polar night jet moves downward, so there is less latitudinal mixing. The degree of mixing in the lower stratosphere thus depends strongly on the position and evolution of the polar night jet and on the amount of descent experienced by the air parcels; these characteristics show considerable interannual variability in both hemispheres. The computed trajectories provide a three-dimensional picture of air motion during the final warming. Large tongues of air are drawn off the vortex and stretched into increasingly long and narrow tongues extending into low latitudes. This vortex erosion process proceeds more rapidly in the NH than in he SH. In the lower stratosphere, the majority of air parcels remain confined within a lingering region of strong potential vorticity gradients into December in the SH and April in the NH, well after the vortex breaks up in the midstratosphere.

  18. On the Motion of Air through the Stratospheric Polar Vortex.

    NASA Astrophysics Data System (ADS)

    Manney, G. L.; Zurek, R. W.; O'Neill, A.; Swinbank, R.

    1994-10-01

    Trajectory calculations using horizontal winds from the U.K. Meteorological Office data assimilation system and vertical velocities from a radiation calculation are used to simulate the three-dimensional motion of air through the stratospheric polar vortex for Northern Hemisphere (NH) and Southern Hemisphere (SH) winters since the launch of the Upper Atmosphere Research Satellite. Throughout the winter, air from the upper stratosphere moves poleward and descends into the middle stratosphere. In the SH lower to middle stratosphere, strongest descent occurs near the edge of the polar vortex, with that edge defined by mixing characteristics. The NH shows a similar pattern in late winter, but in early winter strongest descent is near the center of the vortex, except when wave activity is particularly strong. Strong barriers to latitudinal mixing exist above about 420 K throughout the winter. Below this, the polar night jet is weak in early winter, so air descending below that level mixes between polar and middle latitudes. In late winter, parcels descend less and the polar night jet moves downward, so there is less latitudinal mixing. The degree of mixing in the lower stratosphere thus depends strongly on the position and evolution of the polar night jet and on the amount of descent experienced by the air parcels; these characteristics show considerable interannual variability in both hemispheres.The computed trajectories provide a three-dimensional picture of air motion during the final warming. Large tongues of air are drawn off the vortex and stretched into increasingly long and narrow tongues extending into low latitudes. This vortex erosion process proceeds more rapidly in the NH than in the SH. In the lower stratosphere, the majority of air parcels remain confined within a lingering region of strong potential vorticity gradients into December in the SH and April in the NH, well after the vortex breaks up in the midstratosphere.

  19. Chemical characteristics of air from differing source regions during the Pacific Exploratory Mission-Tropics A (PEM-Tropics A)

    NASA Astrophysics Data System (ADS)

    Board, Ashley S.; Fuelberg, Henry E.; Gregory, Gerald L.; Heikes, Brian G.; Schultz, Martin G.; Blake, Donald R.; Dibb, Jack E.; Sandholm, Scott T.; Talbot, Robert W.

    1999-07-01

    Ten-day backward trajectories are used to determine the origins of air parcels arriving at airborne DC-8 chemical measurement sites during NASA's Pacific Exploratory Mission-Tropics A (PEM-T) that was conducted during August-October 1996. Those sites at which the air had a common geographical origin and transport history are grouped together, and statistical measures of chemical characteristics are computed. Temporal changes in potential temperature are used to determine whether trajectories experience a significant convective influence during the 10-day period. Those trajectories that do not experience a significant convective influence are divided into four geographical categories depending on their origins and paths. Air parcels originating over Africa and South America are characterized by enhanced mixing ratios of O3, CO, HNO3, and PAN. The backward trajectories travel at high altitudes (˜10-11 km), covering long distances due to strong upper-tropospheric westerly winds. The observed enhancement of combustion-related species is attributed to biomass burning from distant sources to the west, extending even to South America. The relatively large value of Be-7 probably is due either to less efficient removal of aerosols from upper tropospheric air or to small stratospheric contributions. Aged marine parcels are found to have relatively small concentrations of burning-related species. Although these trajectories arrive at a wide range of aircraft altitudes, they do not pass over a land mass during the preceding 10-day period. Air passing over Australia but no other land mass exhibits a combustion signature; however, photochemical product species such as O3 and PAN are less enhanced than in the long-range transport category. These trajectories travel shorter distances and are at lower altitudes (˜5-8 km) than those reaching Africa and/or South America. The combustion influence on these parcels is attributed to biomass burning emissions injected over Australia

  20. 36 CFR 910.59 - Development parcel.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Development parcel. 910.59 Section 910.59 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION GENERAL GUIDELINES AND UNIFORM STANDARDS FOR URBAN PLANNING AND DESIGN OF DEVELOPMENT WITHIN THE PENNSYLVANIA...

  1. Cirrus Parcel Model Comparison Project. Phase 1

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, David O'C.; DeMott, Paul J.; Cotton, Richard; Jensen, Eric; Sassen, Kenneth

    2000-01-01

    The Cirrus Parcel Model Comparison (CPMC) is a project of the GEWEX Cloud System Study Working Group on Cirrus Cloud Systems (GCSS WG2). The primary goal of this project is to identify cirrus model sensitivities to the state of our knowledge of nucleation and microphysics. Furthermore, the common ground of the findings may provide guidelines for models with simpler cirrus microphysics modules. We focus on the nucleation regimes of the warm (parcel starting at -40 C and 340 hPa) and cold (-60 C and 170 hPa) cases studied in the GCSS WG2 Idealized Cirrus Model Comparison Project. Nucleation and ice crystal growth were forced through an externally imposed rate of lift and consequent adiabatic cooling. The background haze particles are assumed to be lognormally-distributed H2SO4 particles. Only the homogeneous nucleation mode is allowed to form ice crystals in the HN-ONLY runs; all nucleation modes are switched on in the ALL-MODE runs. Participants were asked to run the HN-lambda-fixed runs by setting lambda = 2 (lambda is further discussed in section 2) or tailoring the nucleation rate calculation in agreement with lambda = 2 (exp 1). The depth of parcel lift (800 m) was set to assure that parcels underwent complete transition through the nucleation regime to a stage of approximate equilibrium between ice mass growth and vapor supplied by the specified updrafts.

  2. Regional Influences of Marcellus Shale Natural Gas Activity: Back-trajectory Analysis of Baltimore/Washington Ethane Concentrations

    NASA Astrophysics Data System (ADS)

    Vinciguerra, T.; Chittams, A.; Dadzie, J.; Deskins, T.; Goncalves, V.; M'Bagui Matsanga, C.; Zakaria, R.; Ehrman, S.; Dickerson, R. R.

    2015-12-01

    Over the past several years, the combined utilization of hydraulic fracturing and horizontal drilling has led to a rapid increase in natural gas production, especially from the Marcellus Shale. To explore the impact of this activity downwind on regions with no natural gas production, the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) Model was used to generate 48-hour back-trajectories for summer, daytime hours from the years 2007-2014 in the Baltimore, MD and Washington, D.C. areas where hourly ethane measurements are available from Photochemical Assessment Monitoring Stations (PAMS). For each of the years investigated, unconventional well counts were obtained for counties in the surrounding states of Pennsylvania, Ohio, West Virginia, and Virginia, and counties exceeding a threshold of 0.05 wells/km2 were designated as counties with a high density of wells. The back-trajectories for each year were separated into two groups: those which passed through counties containing a high density of wells, and those which did not. Back-trajectories passing through high-density counties were further screened by applying a height criterion where trajectories beyond 10% above the mixing layer were excluded. Preliminary results indicate that air parcels with back-trajectories passing within the boundary layer of counties with a high density of unconventional natural gas wells correspond to significantly greater concentrations of observed ethane at these downwind monitors.

  3. Cooling channels design analysis with chaotic laminar trajectory for closed cathode air-cooled PEM fuel cells using non-reacting numerical approach

    NASA Astrophysics Data System (ADS)

    N, W. Mohamed W. A.

    2015-09-01

    The thermal management of Polymer Electrolyte Membrane (PEM) fuel cells contributes directly to the overall power output of the system. For a closed cathode PEM fuel cell design, the use of air as a cooling agent is a non-conventional method due to the large heat load involved, but it offers a great advantage for minimizing the system size. Geometrical aspects of the cooling channels have been identified as the basic parameter for improved cooling performance. Numerical investigation using STAR-CCM computational fluid dynamics platform was applied for non-reacting cooling effectiveness study of various channel geometries for fuel cell application. The aspect ratio of channels and the flow trajectory are the parametric variations. A single cooling plate domain was selected with an applied heat flux of 2400 W/m2 while the cooling air are simulated at Reynolds number of 400 that corresponds to normal air flow velocities using standard 6W fans. Three channel designs of similar number of channels (20 channels) are presented here to analyze the effects of having chaotic laminar flow trajectory compared to the usual straight path trajectory. The total heat transfer between the cooling channel walls and coolant were translated into temperature distribution, maximum temperature gradient, average plate temperature and overall cooling effectiveness analyses. The numerical analysis shows that the chaotic flow promotes a 5% to 10% improvement in cooling effectiveness, depending on the single-axis or multi-axis flow paths applied. Plate temperature uniformity is also more realizable using the chaotic flow designs.

  4. Indications of photochemical histories of Pacific air masses from measurements of atmospheric trace species at Point Arena, California

    NASA Technical Reports Server (NTRS)

    Parrish, D. D.; Hahn, C. J.; Williams, E. J.; Norton, R. B.; Fehsenfeld, F. C.; Singh, H. B.; Shetter, J. D.; Gandrud, B. W.; Ridley, B. A.

    1992-01-01

    Measurements were made of a suite of photochemically active trace species (including light hydrocarbons, ozone, peroxyacetyl nitrate, HNO3, NO3(-), NO(x), and NO(y)) in marine air collected during a 10-day period in April and May 1985 at Point Arena (California), a coastal inflow site. It was found that the mixing ratios of the alkanes, ozone, peroxyacetyl nitrate, and HNO3 correlated with variations in the origins of calculated air parcel trajectories and with variations in the ratios of the light alkanes. The highest levels of alkanes and the photochemical products were found in parcels that had been rapidly transported across the North Pacific Ocean from near the 600-mbar level above the east Asian coast. It is suggested that production over the continents, transport to the marine areas, and parallel removal processes account for much of the observed correlation.

  5. Air mass origin signals in δ 18O of tree-ring cellulose revealed by back-trajectory modeling at the monsoonal Tibetan plateau

    NASA Astrophysics Data System (ADS)

    Wernicke, Jakob; Hochreuther, Philipp; Grießinger, Jussi; Zhu, Haifeng; Wang, Lily; Bräuning, Achim

    2016-12-01

    A profound consideration of stable oxygen isotope source water origins is a precondition for an unambiguous palaeoenvironmental interpretation of terrestrial δ 18O archives. To stress the influence of air mass origins on widely used δ 18O tree-ring chronologies, we conducted correlation analyses between six annually resolved δ 18O tree-ring cellulose ( δ ^{18}O_{TC}) chronologies and mean annual air package origins obtained from backward trajectory modeling. This novel approach has been tested for a transect at the southeastern Tibetan plateau (TP), where air masses with different isotopic composition overlap. Detailed examinations of daily precipitation amounts and monthly precipitation δ 18O values ( δ ^{18}OP) were conducted with the ERA Interim and Laboratoire de Météorologie Dynamique General Circulation Model (LMDZiso) data, respectively. Particularly the southernmost study sites are influenced by a distinct amount effect. Here, air package origin δ ^{18}O_{TC} relations are generally weaker in contrast to our northern located study sites. We found that tree-ring isotope signatures at dry sites with less rain days per year tend to be influenced stronger by air mass origin than tree-ring isotope values at semi-humid sites. That implies that the local hydroclimate history inferred from δ ^{18}O_{TC} archives is better recorded at semi-humid sites.

  6. A simple parcel method for prediction of cumulus onset and area-averaged cloud amount over heterogeneous land surfaces

    NASA Technical Reports Server (NTRS)

    Wetzel, Peter J.

    1990-01-01

    A set of PBL data selected from the Wangara experiment is used to examine the relationship between cumulus amount and the calculated relative humidity of rising parcels. The Wilde et al. (1985) method is compared to two explicit parcel methods. It is shown that predictions using parcel methods, in which surface air is lifted to its equilibrium level while being diluted by a defined amount of mixed layer air, are superior for cloud amount, especially during periods of rapid cloud onset when the mean boundary layer top is swiftly rising through a near-neutral layer. Pending independent verification, it appears that an rms error in instantaneous cloud amount of + or - 10 percent may be achievable.

  7. Effects of Parceling on Model Selection: Parcel-Allocation Variability in Model Ranking.

    PubMed

    Sterba, Sonya K; Rights, Jason D

    2016-01-25

    Research interest often lies in comparing structural model specifications implying different relationships among latent factors. In this context parceling is commonly accepted, assuming the item-level measurement structure is well known and, conservatively, assuming items are unidimensional in the population. Under these assumptions, researchers compare competing structural models, each specified using the same parcel-level measurement model. However, little is known about consequences of parceling for model selection in this context-including whether and when model ranking could vary across alternative item-to-parcel allocations within-sample. This article first provides a theoretical framework that predicts the occurrence of parcel-allocation variability (PAV) in model selection index values and its consequences for PAV in ranking of competing structural models. These predictions are then investigated via simulation. We show that conditions known to manifest PAV in absolute fit of a single model may or may not manifest PAV in model ranking. Thus, one cannot assume that low PAV in absolute fit implies a lack of PAV in ranking, and vice versa. PAV in ranking is shown to occur under a variety of conditions, including large samples. To provide an empirically supported strategy for selecting a model when PAV in ranking exists, we draw on relationships between structural model rankings in parcel- versus item-solutions. This strategy employs the across-allocation modal ranking. We developed software tools for implementing this strategy in practice, and illustrate them with an example. Even if a researcher has substantive reason to prefer one particular allocation, investigating PAV in ranking within-sample still provides an informative sensitivity analysis.

  8. A Study of the Trajectories of Projectiles.

    ERIC Educational Resources Information Center

    Grant, A. Ruari

    1990-01-01

    Described is a procedure for studying the trajectories of projectiles using ball bearings and aluminum foil. Trajectories were measured with and without the effects of air resistance. Multiflash photography was used to determine the flight paths of all objects. (KR)

  9. Automatic parcellation of longitudinal cortical surfaces

    NASA Astrophysics Data System (ADS)

    Alassaf, Manal H.; Hahn, James K.

    2015-03-01

    We present a novel automatic method to parcellate the cortical surfaces of the neonatal brain longitudinal atlas at different stages of development. A labeled brain atlas of newborn at 41 weeks gestational age (GA) is used to propagate labels of anatomical regions of interest to an unlabeled spatio-temporal atlas, which provides a dynamic model of brain development at each week between 28-44 GA weeks. First, labels from the cortical volume of the labeled newborn brain are propagated to an age-matched cortical surface from the spatio-temporal atlas. Then, labels are propagated across the cortical surfaces of each week of the spatio-temporal atlas by registering successive cortical surfaces using a novel approach and an energy optimization function. This procedure incorporates local and global, spatial and temporal information when assigning the labels to each surface. The result is a complete parcellation of 17 neonatal brain surfaces of the spatio-temporal atlas with similar points per labels distributions across weeks.

  10. Shape-based multifeature brain parcellation

    NASA Astrophysics Data System (ADS)

    Nadeem, Saad; Kaufman, Arie

    2016-03-01

    We present a novel approach to parcellate - delineate the anatomical feature (folds, gyri, sulci) boundaries - the brain cortex. Our approach is based on extracting the 3D brain cortical surface mesh from magnetic resonance (MR) images, computing the shape measures (area, mean curvature, geodesic, and travel depths) for this mesh, and delineating the anatomical feature boundaries using these measures. We use angle-area preserving mapping of the cortical surface mesh to a simpler topology (disk or rectangle) to aid in the visualization and delineation of these boundaries. Contrary to commonly used generic 2D brain image atlas-based approaches, we use 3D surface mesh data extracted from a given brain MR imaging data and its specific shape measures for the parcellation. Our method does not require any non-linear registration of a given brain dataset to a generic atlas and hence, does away with the structure similarity assumption critical to the atlas-based approaches. We evaluate our approach using Mindboggle manually labeled brain datasets and achieve the following accuracies: 72.4% for gyri, 78.5% for major sulci, and 98.4% for folds. These results warrant further investigation of this approach as an alternative or as an initialization to the atlas-based approaches.

  11. 76 FR 11297 - New Regional Ground Service for Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ... New Regional Ground Service for Parcels AGENCY: Postal Regulatory Commission. ACTION: Notice. SUMMARY... affecting Parcel Select. The changes involve a new offering identified as Regional Ground service. This... competitive product pursuant to 39 CFR 3015.2.\\1\\ The proposed changes establish a new ``Regional...

  12. 19. John and James Dobson Carpet Mills, West parcel, topographical ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. John and James Dobson Carpet Mills, West parcel, topographical plan, 1986. Barton and Martin, Engineers. 'Topographical Plan for Dobson Mills.' Prepared for Rouse Urban Housing, Inc., Philadelphia, Pennsylvania, 1986. - John & James Dobson Carpet Mill (West Parcel), 4041-4055 Ridge Avenue, Philadelphia, Philadelphia County, PA

  13. The Trajectory Synthesizer Generalized Profile Interface

    NASA Technical Reports Server (NTRS)

    Lee, Alan G.; Bouyssounouse, Xavier; Murphy, James R.

    2010-01-01

    The Trajectory Synthesizer is a software program that generates aircraft predictions for Air Traffic Management decision support tools. The Trajectory Synthesizer being used by researchers at NASA Ames Research Center was restricted in the number of trajectory types that could be generated. This limitation was not sufficient to support the rapidly changing Air Traffic Management research requirements. The Generalized Profile Interface was developed to address this issue. It provides a flexible approach to describe the constraints applied to trajectory generation and may provide a method for interoperability between trajectory generators. It also supports the request and generation of new types of trajectory profiles not possible with the previous interface to the Trajectory Synthesizer. Other enhancements allow the Trajectory Synthesizer to meet the current and future needs of Air Traffic Management research.

  14. Parcellating cortical functional networks in individuals.

    PubMed

    Wang, Danhong; Buckner, Randy L; Fox, Michael D; Holt, Daphne J; Holmes, Avram J; Stoecklein, Sophia; Langs, Georg; Pan, Ruiqi; Qian, Tianyi; Li, Kuncheng; Baker, Justin T; Stufflebeam, Steven M; Wang, Kai; Wang, Xiaomin; Hong, Bo; Liu, Hesheng

    2015-12-01

    The capacity to identify the unique functional architecture of an individual's brain is a crucial step toward personalized medicine and understanding the neural basis of variation in human cognition and behavior. Here we developed a cortical parcellation approach to accurately map functional organization at the individual level using resting-state functional magnetic resonance imaging (fMRI). A population-based functional atlas and a map of inter-individual variability were employed to guide the iterative search for functional networks in individual subjects. Functional networks mapped by this approach were highly reproducible within subjects and effectively captured the variability across subjects, including individual differences in brain lateralization. The algorithm performed well across different subject populations and data types, including task fMRI data. The approach was then validated by invasive cortical stimulation mapping in surgical patients, suggesting potential for use in clinical applications.

  15. Parcellating Cortical Functional Networks in Individuals

    PubMed Central

    Wang, Danhong; Buckner, Randy L.; Fox, Michael D.; Holt, Daphne J.; Holmes, Avram J.; Stoecklein, Sophia; Langs, Georg; Pan, Ruiqi; Qian, Tianyi; Li, Kuncheng; Baker, Justin T.; Stufflebeam, Steven M.; Wang, Kai; Wang, Xiaomin; Hong, Bo; Liu, Hesheng

    2015-01-01

    The capacity to identify the unique functional architecture of an individual’s brain is a critical step towards personalized medicine and understanding the neural basis of variations in human cognition and behavior. Here, we developed a novel cortical parcellation approach to accurately map functional organization at the individual level using resting-state fMRI. A population-based functional atlas and a map of inter-individual variability were employed to guide the iterative search for functional networks in individual subjects. Functional networks mapped by this approach were highly reproducible within subjects and effectively captured the variability across subjects, including individual differences in brain lateralization. The algorithm performed well across different subject populations and data types including task fMRI data. The approach was then validated by invasive cortical stimulation mapping in surgical patients, suggesting great potential for use in clinical applications. PMID:26551545

  16. Automated MRI parcellation of the frontal lobe.

    PubMed

    Ranta, Marin E; Chen, Min; Crocetti, Deana; Prince, Jerry L; Subramaniam, Krish; Fischl, Bruce; Kaufmann, Walter E; Mostofsky, Stewart H

    2014-05-01

    Examination of associations between specific disorders and physical properties of functionally relevant frontal lobe sub-regions is a fundamental goal in neuropsychiatry. Here, we present and evaluate automated methods of frontal lobe parcellation with the programs FreeSurfer(FS) and TOADS-CRUISE(T-C), based on the manual method described in Ranta et al. [2009]: Psychiatry Res 172:147-154 in which sulcal-gyral landmarks were used to manually delimit functionally relevant regions within the frontal lobe: i.e., primary motor cortex, anterior cingulate, deep white matter, premotor cortex regions (supplementary motor complex, frontal eye field, and lateral premotor cortex) and prefrontal cortex (PFC) regions (medial PFC, dorsolateral PFC, inferior PFC, lateral orbitofrontal cortex [OFC] and medial OFC). Dice's coefficient, a measure of overlap, and percent volume difference were used to measure the reliability between manual and automated delineations for each frontal lobe region. For FS, mean Dice's coefficient for all regions was 0.75 and percent volume difference was 21.2%. For T-C the mean Dice's coefficient was 0.77 and the mean percent volume difference for all regions was 20.2%. These results, along with a high degree of agreement between the two automated methods (mean Dice's coefficient = 0.81, percent volume difference = 12.4%) and a proof-of-principle group difference analysis that highlights the consistency and sensitivity of the automated methods, indicate that the automated methods are valid techniques for parcellation of the frontal lobe into functionally relevant sub-regions. Thus, the methodology has the potential to increase efficiency, statistical power and reproducibility for population analyses of neuropsychiatric disorders with hypothesized frontal lobe contributions.

  17. OPTIMUM TRAJECTORIES

    DTIC Science & Technology

    trajectory and the transient trajectories from the steady-state path to the endpoints could be computed separately. The results using this method agreed well with the exact solution and gave a tremendous savings in computing time....described the motion of a body similar to the one under study. The nature of the REAC solutions suggested that the steady-state, or mid-path

  18. STATISTICAL DECOUPLING OF A LAGRANGIAN FLUID PARCEL IN NEWTONIAN COSMOLOGY

    SciTech Connect

    Wang, Xin; Szalay, Alex

    2016-03-20

    The Lagrangian dynamics of a single fluid element within a self-gravitational matter field is intrinsically non-local due to the presence of the tidal force. This complicates the theoretical investigation of the nonlinear evolution of various cosmic objects, e.g., dark matter halos, in the context of Lagrangian fluid dynamics, since fluid parcels with given initial density and shape may evolve differently depending on their environments. In this paper, we provide a statistical solution that could decouple this environmental dependence. After deriving the evolution equation for the probability distribution of the matter field, our method produces a set of closed ordinary differential equations whose solution is uniquely determined by the initial condition of the fluid element. Mathematically, it corresponds to the projected characteristic curve of the transport equation of the density-weighted probability density function (ρPDF). Consequently it is guaranteed that the one-point ρPDF would be preserved by evolving these local, yet nonlinear, curves with the same set of initial data as the real system. Physically, these trajectories describe the mean evolution averaged over all environments by substituting the tidal tensor with its conditional average. For Gaussian distributed dynamical variables, this mean tidal tensor is simply proportional to the velocity shear tensor, and the dynamical system would recover the prediction of the Zel’dovich approximation (ZA) with the further assumption of the linearized continuity equation. For a weakly non-Gaussian field, the averaged tidal tensor could be expanded perturbatively as a function of all relevant dynamical variables whose coefficients are determined by the statistics of the field.

  19. Variability in Parameter Estimates and Model Fit across Repeated Allocations of Items to Parcels

    ERIC Educational Resources Information Center

    Sterba, Sonya K.; MacCallum, Robert C.

    2010-01-01

    Different random or purposive allocations of items to parcels within a single sample are thought not to alter structural parameter estimates as long as items are unidimensional and congeneric. If, additionally, numbers of items per parcel and parcels per factor are held fixed across allocations, different allocations of items to parcels within a…

  20. Emerson Parcel of Dutch Slough Tidal Marsh Restoration Project

    EPA Pesticide Factsheets

    Information about the SFBWQP Emerson Parcel of Dutch Slough Tidal Marsh Restoration Project, part of an EPA competitive grant program to improve SF Bay water quality focused on restoring impaired waters and enhancing aquatic resources.

  1. Hydraulic Hybrid Parcel Delivery Truck Deployment, Testing & Demonstration

    SciTech Connect

    Gallo, Jean-Baptiste

    2014-03-07

    Although hydraulic hybrid systems have shown promise over the last few years, commercial deployment of these systems has primarily been limited to Class 8 refuse trucks. In 2005, the Hybrid Truck Users Forum initiated the Parcel Delivery Working Group including the largest parcel delivery fleets in North America. The goal of the working group was to evaluate and accelerate commercialization of hydraulic hybrid technology for parcel delivery vehicles. FedEx Ground, Purolator and United Parcel Service (UPS) took delivery of the world’s first commercially available hydraulic hybrid parcel delivery trucks in early 2012. The vehicle chassis includes a Parker Hannifin hydraulic hybrid drive system, integrated and assembled by Freightliner Custom Chassis Corp., with a body installed by Morgan Olson. With funding from the U.S. Department of Energy, CALSTART and its project partners assessed the performance, reliability, maintainability and fleet acceptance of three pre-production Class 6 hydraulic hybrid parcel delivery vehicles using information and data from in-use data collection and on-road testing. This document reports on the deployment of these vehicles operated by FedEx Ground, Purolator and UPS. The results presented provide a comprehensive overview of the performance of commercial hydraulic hybrid vehicles in parcel delivery applications. This project also informs fleets and manufacturers on the overall performance of hydraulic hybrid vehicles, provides insights on how the technology can be both improved and more effectively used. The key findings and recommendations of this project fall into four major categories: -Performance, -Fleet deployment, -Maintenance, -Business case. Hydraulic hybrid technology is relatively new to the market, as commercial vehicles have been introduced only in the past few years in refuse and parcel delivery applications. Successful demonstration could pave the way for additional purchases of hydraulic hybrid vehicles throughout the

  2. Numerical Study of Orbital Trajectories about Phobos

    DTIC Science & Technology

    1988-12-01

    COF NUMERICAL STUDY OF ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Robert B. Teets Captain, USAF AFIT/GS0/AA/8 8D- 16 ..................D TIC SELECTEh...ful em t%... . 𔄂 9 ... 3 ...29 ...058_... AFIT/GSO/AA/88D-16 0 NUMERICAL STUDY OF ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Robert B. Teets Captain...ORBITAL TRAJECTORIES ABOUT PHOBOS THESIS Presented to the Faculty of the School of Engineering of the Air Force Institute of Technology Air University In

  3. Flight Trajectory Control Investigation

    DTIC Science & Technology

    1981-03-01

    control algorithms for four-dimensional guidance of a transport air- craft were investigated for feasibility. Cost function constraints on the ptimal...21 3.1.6 Solution Constraints .... ............. ... 25 3.1.7 Trajectory Generator Review .. ......... .. 25 3.2 OPTIMAl CONTROLLER ALGORITHM...value formulation to a six-degree-of-freedom point mass aircraft with all the structural, maneuver, and mission constraints accounted for by using pelalty

  4. A GIS-based shape index for land parcels

    NASA Astrophysics Data System (ADS)

    Demetriou, Demetris; Stillwell, John; See, Linda

    2013-08-01

    Shape analysis is of interest in many fields of spatial science and planning including land management in rural areas. In particular, evaluating the shape of existing land parcels is critical when implementing rural development schemes such as land consolidation. However, existing land parcel shape indices have major deficiencies: completely different shapes of parcels may have the same index value or similar parcel shapes may have different index scores. Thus, there is a clear requirement for a more accurate and reliable measurement method. This paper therefore presents a new parcel shape index (PSI) which integrates a geographical information system (GIS) with a multi-attribute decision-making (MADM) method. It involves the amalgamated outcome of six geometric measures represented by value functions involving a mathematical representation of judgements by experts that compare each geometric measure with that of an optimum parcel shape defined for land consolidation projects. The optimum shape has a PSI value of 1 while the worst shape has a value close to 0. The shape measures used in the model include length of sides, acute angles, reflex angles, boundary points, compactness and regularity. The paper uses data for two case study areas in Cyprus to demonstrate the superiority of the new PSI over three existing shape indices employed in other studies. The methodology utilized here can be implemented in other disciplines dealing with the assessment of objects that can be compared to an optimum.

  5. Chemical characteristics of air from different source regions during the second Pacific Exploratory Mission in the Tropics (PEM-Tropics B)

    NASA Astrophysics Data System (ADS)

    Maloney, Joseph C.; Fuelberg, Henry E.; Avery, Melody A.; Crawford, James H.; Blake, Donald R.; Heikes, Brian G.; Sachse, Glen W.; Sandholm, Scott T.; Singh, Hanwant; Talbot, Robert W.

    2001-12-01

    Ten-day backward trajectories are used to determine the origins of air parcels arriving at locations of airborne DC-8 chemical measurements during NASA's second Pacific Exploratory Mission in the Tropics B that was conducted during February-April 1999. Chemical data at sites where the trajectories had a common geographical origin and transport history are grouped together, and statistical measures of chemical characteristics are computed. Temporal changes in potential temperature are used to determine whether trajectories experienced a significant convective influence during the 10-day period. Trajectories describing the aged marine Southern Hemispheric category remain over the South Pacific Ocean during the 10-day period, and their corresponding chemical signature indicates very clean air. The category aged marine air in the Northern Hemisphere is found to be somewhat dirtier. Subdividing its trajectories based on the direction from which the air had traveled is found to be important in explaining the various chemical signatures. Similarly, long-range northern hemispheric trajectories passing over Asia are subdivided depending on whether they had followed a mostly zonal path, had originated near the Indian Ocean, or had originated near Central or South America and subsequently experienced a stratospheric influence. Results show that the chemical signatures of these subcategories are different from each other. The chemical signature of the southern hemispheric long-range transport category apparently exhibits the effects of pollution from Australia, southern Africa, and South America. Parcels originating over Central and northern South America are found to contain the strongest pollution signature of all categories, due to biomass burning and other sources. The convective category exhibits enhanced values of nitrogen species, probably due to emissions from lightning associated with the convection. Values of various species, including peroxides and acids, confirm

  6. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  7. A trajectory-based classification of ERA-Interim ice clouds in the region of the North Atlantic storm track

    NASA Astrophysics Data System (ADS)

    Wernli, Heini; Boettcher, Maxi; Joos, Hanna; Miltenberger, Annette K.; Spichtinger, Peter

    2016-06-01

    A two-type classification of ice clouds (cirrus) is introduced, based on the liquid and ice water content, LWC and IWC, along air parcel backward trajectories from the clouds. In situ cirrus has no LWC along the trajectory segment containing IWC; it forms via nucleation from the gas phase. In contrast, liquid-origin cirrus has both LWC and IWC along their backward trajectories; it forms via lifting from the lower troposphere and freezing of mixed-phase clouds. This classification is applied to 12 years of ERA-Interim ice clouds in the North Atlantic region. Between 400 and 500 hPa more than 50% are liquid-origin cirrus, whereas this frequency decreases strongly with altitude (<10% at 200 hPa). The relative frequencies of the two categories vary only weakly with season. More than 50% of in situ cirrus occur on top of liquid-origin cirrus, indicating that they often form in response to the strong lifting accompanying the formation of liquid-origin cirrus.

  8. Trajectory Analysis

    NASA Technical Reports Server (NTRS)

    Burke, Laura M.

    2004-01-01

    The Systems Analysis Branch performs trajectory and systems analysis for next-generation launch vehicle and space transportation technologies. Currently the branch is supporting the Project Prometheus with analysis of nuclear electric and nuclear thermal propulsion missions to a variety of destinations. Within Project Prometheus a proposed mission to Jupiter and three of the planet sized icy moons that orbit it is developing. The Jupiter Icy Moons Orbiter (JIMO) as the project is being called will enable detailed scientific investigation of Jupiter's moons Callisto, Ganymede, and Europa. These moons were choose to orbit for intensive study in particular because they are each believed to have water, energy, and organic material. The JIMO mission will utilize nuclear fission power and electric propulsion in order to allow the spacecraft to orbit the moons at close range for long durations of time. My assignment this summer was to assist in developing a trajectory analysis for the spacecraft system the Jupiter Icy Moons Orbiter by rewriting an inefficient Excel file into a more efficient FORTRAN program. This program has been created for use planning the trajectory of the Jupiter Icy Moons Orbiter Mission. The program uses a database of thousands of data points representing flight time, burn time, thrust, mass of the propellant used, final mass of the spacecraft, ratio of finals mass to initial mass, and change in velocity that a spacecraft experiences during each phase in the Jupiter Icy Moons Orbiter Mission. The trajectory program is capable of taking a specific user entered specific impulse (isp), final mass fraction, and thrust (P(sub J)/m0) and through the use of cubic splines to fit specific data curves, the program can locate the exact flight time linked to the user specified values of specific impulse and final over initial mass fraction. Currently, the database used by the program to calculate flight times for a given thrust is only for isps in the range of

  9. Multiple trajectory analysis of MLS observed stratospheric chemical ozone loss in Arctic winter 1995/96

    NASA Astrophysics Data System (ADS)

    Lemmen, C.; Riese, R.; Grooss, J.-U.; Mueller, R.

    2003-04-01

    Daily ozone loss rates and total chemical ozone depletion during Arctic winter 1995/96 were evaluated based on ozone measurements by the Microwave Limb Sounder (MLS) instrument onboard the Upper Atmosphere Research Satellite (UARS). Employing the 3-dimensional transport scheme of the Chemical Lagrangian Model of the Stratosphere (CLaMS), trajectories from successive satellite measurements were compared with each other using a variation of the Match technique, such that ozone concentration differences between double sounded (``matched'') air parcels represent chemical ozone loss. The ensemble average of many (typically 30--150) matches yields an average ozone depletion rate for the area covered by the trajectories. Total ozone loss from late December to early March was 1.4 ppmv at the 475 K isentropic level within the vortex core (PV > 45 PVU at 475 K). Ozone loss decreased towards the edge of the vortex, no significant ozone loss could be observed in the outer vortex edge (between ≈ 27 and ≈ 35 PVU). Daily ozone loss was found to average 10 ppbv/day throughout January and throughout the extended vortex area. For the month of February daily ozone loss rates were highly variable and peaked at 40 ppbv/day in the vortex (≈ 35 PVU). In this study, no chemical ozone loss could be observed in the outer vortex edge region during February, which suggests that the dynamically defined vortex boundary separated two different chemical regimes during February, but not in January.

  10. DESCRIPTION OF ATMOSPHERIC TRANSPORT PROCESSES IN EULERIAN AIR QUALITY MODELS

    EPA Science Inventory

    Key differences among many types of air quality models are the way atmospheric advection and turbulent diffusion processes are treated. Gaussian models use analytical solutions of the advection-diffusion equations. Lagrangian models use a hypothetical air parcel concept effecti...

  11. Semi-automatic parcellation of the corpus striatum

    NASA Astrophysics Data System (ADS)

    Al-Hakim, Ramsey; Nain, Delphine; Levitt, James; Shenton, Martha; Tannenbaum, Allen

    2007-03-01

    The striatum is the input component of the basal ganglia from the cerebral cortex. It includes the caudate, putamen, and nucleus accumbens. Thus, the striatum is an important component in limbic frontal-subcortical circuitry and is believed to be relevant both for reward-guided behaviors and for the expression of psychosis. The dorsal striatum is composed of the caudate and putamen, both of which are further subdivided into pre- and post-commissural components. The ventral striatum (VS) is primarily composed of the nucleus accumbens. The striatum can be functionally divided into three broad regions: 1) a limbic; 2) a cognitive and 3) a sensor-motor region. The approximate corresponding anatomic subregions for these 3 functional regions are: 1) the VS; 2) the pre/post-commissural caudate and the pre-commissural putamen and 3) the post-commissural putamen. We believe assessing these subregions, separately, in disorders with limbic and cognitive impairment such as schizophrenia may yield more informative group differences in comparison with normal controls than prior parcellation strategies of the striatum such as assessing the caudate and putamen. The manual parcellation of the striatum into these subregions is currently defined using certain landmark points and geometric rules. Since identification of these areas is important to clinical research, a reliable and fast parcellation technique is required. Currently, only full manual parcellation using editing software is available; however, this technique is extremely time intensive. Previous work has shown successful application of heuristic rules into a semi-automatic platform1. We present here a semi-automatic algorithm which implements the rules currently used for manual parcellation of the striatum, but requires minimal user input and significantly reduces the time required for parcellation.

  12. A Lagrangian trajectory view on transport and mixing processes between the eye, eyewall, and environment using a high resolution simulation of Hurricane Bonnie (1998)

    NASA Technical Reports Server (NTRS)

    Cram, Thomas A.; Persing, John; Montgomery, Michael T.; Braun, Scott A.

    2006-01-01

    The transport and mixing characteristics of a large sample of air parcels within a mature and vertically sheared hurricane vortex is examined. Data from a high-resolution (2 km grid spacing) numerical simulation of "real-case" Hurricane Bonnie (1998) is used to calculate Lagrangian trajectories of air parcels in various subdomains of the hurricane (namely, the eye, eyewall, and near-environment) to study the degree of interaction (transport and mixing) between these subdomains. It is found that 1) there is transport and mixing from the low-level eye to the eyewall that carries high- Be air which can enhance the efficiency of the hurricane heat engine; 2) a portion of the low-level inflow of the hurricane bypasses the eyewall to enter the eye, that both replaces the mass of the low-level eye and lingers for a sufficient time (order 1 hour) to acquire enhanced entropy characteristics through interaction with the ocean beneath the eye; 3) air in the mid- to upper-level eye is exchanged with the eyewall such that more than half the air of the eye is exchanged in five hours in this case of a sheared hurricane; and 4) that one-fifth of the mass in the eyewall at a height of 5 km has an origin in the mid- to upper-level environment where thet(sub e) is much less than in the eyewall, which ventilates the ensemble average eyewall theta(sub e) by about 1 K. Implications of these findings to the problem of hurricane intensity forecasting are discussed.

  13. Center of parcel with picture tube wall along walkway. Leaning ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Center of parcel with picture tube wall along walkway. Leaning Tower of Bottle Village at frame right; oblique view of Rumpus Room, remnants of Little Hut destroyed by Northridge earthquake at frame left. Camera facing northeast. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  14. United Parcel Service Evaluates Hybrid Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2010-02-01

    This fact sheet describes how the National Renewable Energy Laboratory's Fleet Test and Evaluation team evaluated the 12-month, in-service performance of six Class 4 hybrid electric delivery vans - fueled by regular diesel - and six comparable conventional diesel vans operated by the United Parcel Service.

  15. View of structures at rear of parcel with 12' scale ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of structures at rear of parcel with 12' scale (in tenths). From right: edge of Round House, Pencil house, Shell House, edge of School House. Heart Shrine made from mortared car headlights at frame left. Camera facing east. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  16. 7 CFR 1955.140 - Sale in parcels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 14 2012-01-01 2012-01-01 false Sale in parcels. 1955.140 Section 1955.140 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE...

  17. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated...

  18. Center of parcel with mosaics. Mosaics consist of everyday throwaway ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Center of parcel with mosaics. Mosaics consist of everyday throwaway objects of all kinds set in concrete mortar on ground. Leaning Tower of Bottle Village in front of Rumpus Room primary façade with 12' scale (in tenths). Camera facing north. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  19. A multi-modal parcellation of human cerebral cortex.

    PubMed

    Glasser, Matthew F; Coalson, Timothy S; Robinson, Emma C; Hacker, Carl D; Harwell, John; Yacoub, Essa; Ugurbil, Kamil; Andersson, Jesper; Beckmann, Christian F; Jenkinson, Mark; Smith, Stephen M; Van Essen, David C

    2016-08-11

    Understanding the amazingly complex human cerebral cortex requires a map (or parcellation) of its major subdivisions, known as cortical areas. Making an accurate areal map has been a century-old objective in neuroscience. Using multi-modal magnetic resonance images from the Human Connectome Project (HCP) and an objective semi-automated neuroanatomical approach, we delineated 180 areas per hemisphere bounded by sharp changes in cortical architecture, function, connectivity, and/or topography in a precisely aligned group average of 210 healthy young adults. We characterized 97 new areas and 83 areas previously reported using post-mortem microscopy or other specialized study-specific approaches. To enable automated delineation and identification of these areas in new HCP subjects and in future studies, we trained a machine-learning classifier to recognize the multi-modal 'fingerprint' of each cortical area. This classifier detected the presence of 96.6% of the cortical areas in new subjects, replicated the group parcellation, and could correctly locate areas in individuals with atypical parcellations. The freely available parcellation and classifier will enable substantially improved neuroanatomical precision for studies of the structural and functional organization of human cerebral cortex and its variation across individuals and in development, aging, and disease.

  20. A multi-modal parcellation of human cerebral cortex

    PubMed Central

    Glasser, Matthew F; Harwell, John; Yacoub, Essa; Ugurbil, Kamil; Andersson, Jesper; Beckmann, Christian F; Jenkinson, Mark; Smith, Stephen M; Van Essen, David C

    2016-01-01

    Understanding the amazingly complex human cerebral cortex requires a map (or parcellation) of its major subdivisions, known as cortical areas. Making an accurate areal map has been a century-old objective in neuroscience. Using multi-modal magnetic resonance images from the Human Connectome Project (HCP) and an objective semi-automated neuroanatomical approach, we delineated 180 areas per hemisphere bounded by sharp changes in cortical architecture, function, connectivity, and/or topography in a precisely aligned group average of 210 healthy young adults. We characterized 97 new areas and 83 areas previously reported using post-mortem microscopy or other specialized study-specific approaches. To enable automated delineation and identification of these areas in new HCP subjects and in future studies, we trained a machine-learning classifier to recognize the multi-modal ‘fingerprint’ of each cortical area. This classifier detected the presence of 96.6% of the cortical areas in new subjects, replicated the group parcellation, and could correctly locate areas in individuals with atypical parcellations. The freely available parcellation and classifier will enable substantially improved neuroanatomical precision for studies of the structural and functional organization of human cerebral cortex and its variation across individuals and in development, aging, and disease. PMID:27437579

  1. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated Articles From Hawaii and the Territories § 318.13-15 Parcel post inspection. Inspectors are authorized to... Hawaii, Puerto Rico, Guam, the Commonwealth of the Northern Mariana Islands, or the U.S. Virgin...

  2. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated Articles From Hawaii and the Territories § 318.13-15 Parcel post inspection. Inspectors are authorized to... Hawaii, Puerto Rico, Guam, the Commonwealth of the Northern Mariana Islands, or the U.S. Virgin...

  3. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated Articles From Hawaii and the Territories § 318.13-15 Parcel post inspection. Inspectors are authorized to... Hawaii, Puerto Rico, Guam, the Commonwealth of the Northern Mariana Islands, or the U.S. Virgin...

  4. 7 CFR 318.13-15 - Parcel post inspection.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... SERVICE, DEPARTMENT OF AGRICULTURE STATE OF HAWAII AND TERRITORIES QUARANTINE NOTICES Regulated Articles From Hawaii and the Territories § 318.13-15 Parcel post inspection. Inspectors are authorized to... Hawaii, Puerto Rico, Guam, the Commonwealth of the Northern Mariana Islands, or the U.S. Virgin...

  5. 77 FR 43561 - Proposed Eligibility Criteria for Bound Printed Matter Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... criterion for eligibility of Bound Printed Matter (BPM) parcels by adding a physical density threshold for....gov , with a subject line of ``New Eligibility for BPM Parcels.'' Faxed comments are not accepted. FOR.... SUPPLEMENTARY INFORMATION: BPM parcels is an economical ground-based product containing qualifying bound...

  6. 76 FR 17784 - Forwarding and Return Service for Parcel Select Mailpieces

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-31

    ... 111 Forwarding and Return Service for Parcel Select Mailpieces AGENCY: Postal Service TM . ACTION... Parcel Select mailpieces and to eliminate the option to request discontinuance of forwarding. The Postal Service also implements a new price for Parcel Select forwards and returns; those pieces will now pay...

  7. 76 FR 14284 - Domestic Shipping Services Product Launch of Parcel Select Regional Ground

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    ... 111 Domestic Shipping Services Product Launch of Parcel Select Regional Ground AGENCY: Postal Service..., Parcel Select Regional Ground \\TM\\ service. DATES: Effective Date: April 17, 2011. FOR FURTHER... changes outlined by USPS on the introduction of Parcel Select Regional Ground service. This final...

  8. Use of Item Parceling in Structural Equation Modeling with Missing Data

    ERIC Educational Resources Information Center

    Orcan, Fatih

    2013-01-01

    Parceling is referred to as a procedure for computing sums or average scores across multiple items. Parcels instead of individual items are then used as indicators of latent factors in the structural equation modeling analysis (Bandalos 2002, 2008; Little et al., 2002; Yang, Nay, & Hoyle, 2010). Item parceling may be applied to alleviate some…

  9. Determination of upwind and downwind areas of Seoul, Korea using trajectory analysis.

    SciTech Connect

    Oh, H. S.; Ghim, Y. S.; Kim, J. Y.; Chang, Y. S.

    2010-09-01

    To identify the domains that have the greatest impacts on air quality at the surface, both the upwind and downwind areas of Seoul were determined by season using refined wind fields. Four consecutive days were selected as the study period typical of each season. The mesoscale meteorology of the study period was reproduced by using the MM5 prognostic meteorological model (PSU/NCAR Mesoscale Model) with horizontally nested grids. The gridded meteorological field, which was used on the study area of 242 km x 226 km with grid spacing of 2 km, was generated by using the CALMET diagnostic meteorological model. Upwind and downwind areas of Seoul were determined by calculating 24-hour backward and forward air parcel trajectories, respectively, with u, v, and w velocity vectors. The results showed that the upwind and downwind areas were extended far to the northwest and the southeast as a result of high wind speeds in the spring and winter, while they were restricted on the fringe of Seoul in the summer and fall.

  10. Generation and Evaluation of a Cortical Area Parcellation from Resting-State Correlations

    PubMed Central

    Gordon, Evan M.; Laumann, Timothy O.; Adeyemo, Babatunde; Huckins, Jeremy F.; Kelley, William M.; Petersen, Steven E.

    2016-01-01

    The cortical surface is organized into a large number of cortical areas; however, these areas have not been comprehensively mapped in the human. Abrupt transitions in resting-state functional connectivity (RSFC) patterns can noninvasively identify locations of putative borders between cortical areas (RSFC-boundary mapping; Cohen et al. 2008). Here we describe a technique for using RSFC-boundary maps to define parcels that represent putative cortical areas. These parcels had highly homogenous RSFC patterns, indicating that they contained one unique RSFC signal; furthermore, the parcels were much more homogenous than a null model matched for parcel size when tested in two separate datasets. Several alternative parcellation schemes were tested this way, and no other parcellation was as homogenous as or had as large a difference compared with its null model. The boundary map-derived parcellation contained parcels that overlapped with architectonic mapping of areas 17, 2, 3, and 4. These parcels had a network structure similar to the known network structure of the brain, and their connectivity patterns were reliable across individual subjects. These observations suggest that RSFC-boundary map-derived parcels provide information about the location and extent of human cortical areas. A parcellation generated using this method is available at http://www.nil.wustl.edu/labs/petersen/Resources.html. PMID:25316338

  11. Generation and Evaluation of a Cortical Area Parcellation from Resting-State Correlations.

    PubMed

    Gordon, Evan M; Laumann, Timothy O; Adeyemo, Babatunde; Huckins, Jeremy F; Kelley, William M; Petersen, Steven E

    2016-01-01

    The cortical surface is organized into a large number of cortical areas; however, these areas have not been comprehensively mapped in the human. Abrupt transitions in resting-state functional connectivity (RSFC) patterns can noninvasively identify locations of putative borders between cortical areas (RSFC-boundary mapping; Cohen et al. 2008). Here we describe a technique for using RSFC-boundary maps to define parcels that represent putative cortical areas. These parcels had highly homogenous RSFC patterns, indicating that they contained one unique RSFC signal; furthermore, the parcels were much more homogenous than a null model matched for parcel size when tested in two separate datasets. Several alternative parcellation schemes were tested this way, and no other parcellation was as homogenous as or had as large a difference compared with its null model. The boundary map-derived parcellation contained parcels that overlapped with architectonic mapping of areas 17, 2, 3, and 4. These parcels had a network structure similar to the known network structure of the brain, and their connectivity patterns were reliable across individual subjects. These observations suggest that RSFC-boundary map-derived parcels provide information about the location and extent of human cortical areas. A parcellation generated using this method is available at http://www.nil.wustl.edu/labs/petersen/Resources.html.

  12. Interpretation of NO(x)/NO(y) observations from AASE-2 using a model of chemistry along trajectories

    NASA Technical Reports Server (NTRS)

    Kawa, S. R.; Fahey, D. W.; Wilson, J. C.; Schoeberl, M. R.; Douglass, A. R.; Stolarski, R. S.; Woodbridge, E. L.; Jonsson, H.; Lait, L. R.; Newman, P. A.

    1993-01-01

    In situ measurements of NO and NO(y) are used to derive the ratio NO(x)/NO(y) along the flight track of the NASA ER-2 aircraft. Data are presented for two flights at midlatitudes in October 1991 during the Airborne Arctic Stratospheric Expedition-2 (AASE-2). Aerosol particle surface area was concurrently measured. The observations are compared with a photochemical model integrated along back trajectories from the aircraft flight track. Comparison of observations with the model run along trajectories and at a fixed position clearly and quantitatively demonstrates the importance of an air parcel's dynamic history in interpretation of local chemical observations. Comparison of the data with model runs under different assumptions regarding heterogeneous chemistry further reinforces the case for occurrence of the reaction of N2O5 + H2O on sulfate aerosol surfaces in the atmosphere. Finally, comparisons for which relative changes in the model and the data are not consistent caution that our ability to resolve all the observations is not yet complete.

  13. A Novel Approach to Generate Essential New CALIPSO-based Products: Biomass Burning Plume Injection Height Using CALIOP, MODIS and the NASA Langley Trajectory Model

    NASA Astrophysics Data System (ADS)

    Vaughan, M.; Soja, A. J.; Fairlie, T. D.; Westberg, D. J.; Pouliot, G.

    2012-12-01

    There is a significant connection between biomass burning (BB) emissions, the terrestrial environment and the atmosphere, which has strong implications for feedbacks to Air Quality and to the climate system. BB has the potential to alter numerous land and atmospheric processes and their full influence to feedback to interactive systems is currently being exposed (i.e. black carbon on spring Arctic ice). The heights to which BB emissions are injected influence their transport, their interaction with clouds, which alters albedo, and their ability to modify patterns of precipitation. We are working with our applications partners, primarily the Environmental Protection Agency and regional partners, to generate BB plume injection height products using multiple platforms, sensors and models (CALIOP, MODIS, NOAA HMS, Langley Trajectory Model) that will provide value to national and international scientific and air quality communities, the CALIPSO science and algorithm teams, and to public land, fire, and air quality management and regulations communities. Specifically, we are: (1) developing mean statistics that link CALIOP air parcels and BB injection height to the variables that control these dynamics, which include ecosystems, fire-specific and meteorological variables; and (2) defining the daily evolution of smoke plumes for specific fires. Statistics that link fire behavior and weather to plume rise are crucial for verifying and enhancing plume rise parameterization in regional- and global-scale models used for air quality, chemical transport and climate.

  14. A tracking approach to parcellation of the cerebral cortex.

    PubMed

    Adamson, Chris; Johnston, Leigh; Inder, Terrie; Rees, Sandra; Mareels, Iven; Egan, Gary

    2005-01-01

    The cerebral cortex is composed of regions with distinct laminar structure. Functional neuroimaging results are often reported with respect to these regions, usually by means of a brain "atlas". Motivated by the need for more precise atlases, and the lack of model-based approaches in prior work in the field, this paper introduces a novel approach to parcellating the cortex into regions of distinct laminar structure, based on the theory of target tracking. The cortical layers are modelled by hidden Markov models and are tracked to determine the Bayesian evidence of layer hypotheses. This model-based parcellation method, evaluated here on a set of histological images of the cortex, is extensible to 3-D images.

  15. Rating of acceptable load in manual sorting of postal parcels.

    PubMed

    Stålhammar, H R; Louhevaara, V; Troup, J D

    1996-10-01

    The psychophysical test, the rating of acceptable load (RAL) were used to assess acceptable weights for dynamic lifting in postal workers engaged in sorting parcels. The standard test (RALSt) and a work-simulating test (RALW) were administered to 103 volunteers: all experienced male sorters. In the RALSt, subjects selected the weight which would be acceptable for lifting in a box with handles from table to floor and back to the table once every 5 min for the working day. for the RALW, the box was without handles and the weight was chosen to be acceptable for transfer 4-6 times/min from a table to the parcel container and back to the table. Both tests were made during normal working hours at postal sorting centres. The overall means for RALSt and RALW were 16.4 kg and 9.4 kg respectively (p < 0.001): both being substantially higher than the average parcel weight of 4 kg. The RALSt and RALW tests proved to be repetitive and sensitive for differentiating the effects of load and task variable in actual manual material handling. Thus they appear to be applicable to the evaluation of manual materials handling problems.

  16. A Parcellation Scheme for Human Left Lateral Parietal Cortex

    PubMed Central

    Nelson, Steven M.; Cohen, Alexander L.; Power, Jonathan D.; Wig, Gagan S.; Miezin, Francis M.; Wheeler, Mark E.; Velanova, Katerina; Donaldson, David I.; Phillips, Jeffrey S.; Schlaggar, Bradley L.; Petersen, Steven E.

    2010-01-01

    SUMMARY The parietal lobe has long been viewed as a collection of architectonic and functional subdivisions. Though much parietal research has focused on mechanisms of visuospatial attention and control-related processes, more recent functional neuroimaging studies of memory retrieval have reported greater activity in left lateral parietal cortex (LLPC) when items are correctly identified as previously studied (“old”) vs. unstudied (“new”). These studies have suggested functional divisions within LLPC that may provide distinct contributions towards recognition memory judgments. Here, we define regions within LLPC by developing a novel parcellation scheme that integrates data from resting state functional connectivity MRI (rsfcMRI) and functional MRI (fMRI). This combined approach results in a six-fold parcellation of LLPC based on the presence (or absence) of memory retrieval-related activity, dissociations in the profile of task-evoked timecourses, and membership in large-scale brain networks. This parcellation should serve as a roadmap for future investigations aimed at understanding LLPC function. PMID:20624599

  17. Estimations of Forest fire Smoke Forcing From Surface Measurements, Satellite Data, and Trajectory Modeling

    NASA Astrophysics Data System (ADS)

    Cox, S. J.; Stackhouse, P. W.; Baum, B. A.; Pierce, R. B.; Harvey, V. L.; Mikovitz, J. C.; Chiacchio, M.

    2002-05-01

    Methods of using satellite and surface measurements along with trajectory modeling to determine the radiative effect of large boreal forest fires are developed. We present results of surface and top of atmosphere shortwave radiative forcings due to smoke from a very large forest fire outbreak in Manitoba, Canada in July and August 1989. These fires resulted in a large smoke plume over a wide area over the two months. The LaRC trajectory model (LTM) (Pierce et al., 1997) was run in time forward mode for the July-August 1989 time period. The model was seeded with fire pixels as recognized by the Baum and Trepte (1999) smoke/fire/cloud mask. Meteorological data was taken from the European Centre for Medium-Range Weather Forecasts 15-year reanalysis (ERA-15). Air parcels were traced from fire regions over a period of five days globally on a 2.5o equal angle grid. Areas with large numbers of trajectories originating from boundary layer air in fire regions were considered to be likely to be influenced by smoke. An analysis of the effects of the smoke from the Manitoba fires at Canadian surface radiometric sites was performed. Hourly shortwave surface fluxes were compared to a variety of radiative transfer model calculations, satellite data products, and trajectory model results. Numbers and ages of fire-originating trajectories passing within a two degree adius of each of the sites were collected. A theoretical "clean sky" (i.e., with no aerosols or clouds) surface shortwave flux was calculated at each surface site for each hour in July and August using the Fu-Liou radiative transfer code with TOMS ozone values and GEOS-1 meteorology. July 23, 1989 was taken as a first test case. Smoke was heavy over the fire region of Manitoba and Ontario, and both the trajectory model and TOMS showed a tongue of smoke advected far east of the fire region, over the Canadian maritime provinces. At solar noon over each of five stations (Winnipeg, Moosonee, Big Trout Lake, Fredericton, and

  18. Intrinsic functional connectivity pattern-based brain parcellation using normalized cut

    NASA Astrophysics Data System (ADS)

    Cheng, Hewei; Song, Dandan; Wu, Hong; Fan, Yong

    2012-02-01

    In imaging data based brain network analysis, a necessary precursor for constructing meaningful brain networks is to identify functionally homogeneous regions of interest (ROIs) for defining network nodes. For parcellating the brain based on resting state fMRI data, normalized cut is one widely used clustering algorithm which groups voxels according to the similarity of functional signals. Due to low signal to noise ratio (SNR) of resting state fMRI signals, spatial constraint is often applied to functional similarity measures to generate smooth parcellation. However, improper spatial constraint might alter the intrinsic functional connectivity pattern, thus yielding biased parcellation results. To achieve reliable and least biased parcellation of the brain, we propose an optimization method for the spatial constraint to functional similarity measures in normalized cut based brain parcellation. Particularly, we first identify the space of all possible spatial constraints that are able to generate smooth parcellation, then find the spatial constraint that leads to the brain parcellation least biased from the intrinsic function pattern based parcellation, measured by the minimal Ncut value calculated based on the functional similarity measure of original functional signals. The proposed method has been applied to the parcellation of medial superior frontal cortex for 20 subjects based on their resting state fMRI data. The experiment results indicate that our method can generate meaningful parcellation results, consistent with existing functional anatomy knowledge.

  19. The covariance of air quality conditions in six cities in Southern Germany - The role of meteorology.

    PubMed

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2017-01-01

    This paper analyzed air quality in six cities in Southern Germany (Ulm, Augsburg, Konstanz, Freiburg, Stuttgart and Munich), in conjunction with the prevailing synoptic conditions. Air quality was estimated through the calculation of a daily Air Stress Index (ASI) constituted by five independent components, each one expressing the contribution of one of the five main pollutants (PM10, O3, SO2, NO2 and CO) to the total air stress. As it was deduced from ASI components, PM10 from combustion sources and photochemically produced tropospheric O3 are the most hazardous pollutants at the studied sites, throughout cold and warm periods respectively, yet PM10 contribute substantially to the overall air stress during both seasons. The influence of anticyclonic high pressure systems, leading to atmospheric stagnation, was associated with increased ASI values, mainly due to the entrapment of PM10. Moderate air stress was generally estimated in all cities however a cleaner atmosphere was detected principally in Freiburg when North Europe was dominated by low pressure systems. Daily events of notably escalated ASI values were further analyzed with backward air mass trajectories. Throughout cold period, ASI episodes were commonly related to eastern airflows carrying exogenous PM10 originated from eastern continental Europe. During warm period, ASI episodes were connected to the arrival of regionally circulated air parcels reflecting lack of dispersion and accumulation of pollutants in accordance with the synoptic analysis.

  20. Polychlorinated naphthalenes and coplanar polychlorinated biphenyls in arctic air

    SciTech Connect

    Harner, T.; Kylin, H.; Bidleman, T.F.; Barrie, L.A.; Halsall, C.; Strachan, W.M.J.; Fellin, P.

    1998-11-01

    Concentrations of polychlorinated naphthalenes (PCNs) are reported for the first time in arctic air. The data represent combined air samples from the Barents Sea, eastern Arctic Ocean, Norwegian Sea, and two land-based monitoring stations at Alert, Canada, and Dunai Island in eastern Siberia, Russia. Values for {Sigma}PCN were 6--49 for shipboard samples and 0.3--8 for land-based stations and were dominated by the 3-Cl and 4-Cl homologues, which accounted for 90--95% of the total mass. Average values for {Sigma}PCB for the shipboard samples were 126, 24, and 75 for the Barents Sea, eastern Arctic, and Norwegian Sea, respectively. Three-dimensional 5-day air parcel back-trajectories arriving at the ship at 850 and 925 hPa suggested that elevated PCB and PCN concentrations for shipboard samples originated in Europe. Concentrations (fg m{sup {minus}3}) of coplanar PCBs in arctic air were 3--40 (PCB 77) and 0.3--8 (PCB 126) -- about an order of magnitude lower than in urban air. Higher concentrations of PCB 77 and PCB 126, 347 and 5.0 (fg m{sup {minus}3}), respectively, were found in the Barents Sea for two samples with elevated {Sigma}PCBs.

  1. Evaluation of aerosol sources at European high altitude background sites with trajectory statistical methods

    NASA Astrophysics Data System (ADS)

    Salvador, P.; Artíñano, B.; Pio, C. A.; Afonso, J.; Puxbaum, H.; Legrand, M.; Hammer, S.; Kaiser, A.

    2009-04-01

    back-trajectories have been grouped into clusters, each one representing a characteristic meteorological scenario. Some common features have been detected for the clusters obtained in the three monitoring sites. A clear seasonal pattern has been observed with marked fast westerly and northerly Atlantic flows during the winter, to low speed air circulation flows in summertime. The transition period between the occurrence of the longest trajectories in winter and the shortest ones in summer has been characterised by the advection of moderate flows from the north-eastern and eastern European mainland areas. Meteorological scenarios represented by trajectories coming from the Mediterranean basin and North-African regions, have also occurred during the summer months. Then, Redistribution Concentration Fields (RCF, Stohl, 1996) have been computed for each single station and for SIL and PDD together with the aim to obtain more reliable information on PM10 sources, for the whole sampling period and also for the summer and winter seasons. With this methodology, it is possible to obtain spatial distributions of concentrations for specific tracers of PM sources. High concentration values of the element C obtained over a geographical region means that, on average, air parcels passing over that region result in high concentrations of the element C at the receptor site. The main results obtained with this analysis, suggests that current carbonaceous aerosol concentrations in central Europe are likely to be influenced significantly during the winter and autumn months by long-range transport of PM from the north-eastern and eastern regions of Europe. Emissions produced by fossil-fuel and biomass burning processes in these areas, are probably the main sources contributing to the transported aerosol. In contrast, in summer there is a higher contribution of the emissions from local and regional sources on the OC and EC levels at these background sites (Germany, Poland and the Baltic

  2. Trajectories associated to regional and extra-regional pollen transport in the southeast of Buenos Aires province, Mar del Plata (Argentina).

    PubMed

    Gassmann, María I; Pérez, Claudio F

    2006-05-01

    Long range transport of airborne pollen has been seldom studied in South America. Backward trajectories of Celtis and Nothofagus pollen grains trapped over a meteorological station outside Mar del Plata City were calculated in one-hour steps using the regional hybrid model developed by the NOAA (HYSPLIT 4.5) and the data of the NCEP filed in the NOAA server. Results showed that the observed trajectories agree with the location of vegetation sources of the collected tree species. In the case of Celtis, the transport was associated to anticyclones located east of the city, generating winds with a N-NE component, which produce pollen cloud advection from the Celtis forests located some tens of kilometers to the N and NE of the city. The sources of Nothofagus pollen correspond to a narrow strip on the Andes slopes between 39 degrees and 55 degrees S, at least 1100 km to the SW of Mar del Plata. The transport was associated to eastward displacement of the troughs corresponding to the Westerlies circulation and the presence of an anticyclone system that brings back Nothofagus pollen towards Mar del Plata area.

  3. Subject-specific functional parcellation via Prior Based Eigenanatomy

    PubMed Central

    Dhillon, Paramveer S.; Wolk, David A.; Das, Sandhitsu R.; Ungar, Lyle H.; Gee, James C.; Avants, Brian B.

    2015-01-01

    We present a new framework for prior-constrained sparse decomposition of matrices derived from the neuroimaging data and apply this method to functional network analysis of a clinically relevant population. Matrix decomposition methods are powerful dimensionality reduction tools that have found widespread use in neuroimaging. However, the unconstrained nature of these totally data-driven techniques makes it difficult to interpret the results in a domain where network-specific hypotheses may exist. We propose a novel approach, Prior Based Eigenanatomy (p-Eigen), which seeks to identify a data-driven matrix decomposition but at the same time constrains the individual components by spatial anatomical priors (probabilistic ROIs). We formulate our novel solution in terms of prior-constrained ℓ1 penalized (sparse) principal component analysis. p-Eigen starts with a common functional parcellation for all the subjects and refines it with subject-specific information. This enables modeling of the inter-subject variability in the functional parcel boundaries and allows us to construct subject specific networks with reduced sensitivity to ROI placement. We show that while still maintaining correspondence across subjects, p-Eigen extracts biologically-relevant and patient-specific functional parcels that facilitate hypothesis-driven network analysis. We construct Default Mode Network (DMN) connectivity graphs using p-Eigen refined ROIs and use them in a classification paradigm. Our results show that the functional connectivity graphs derived from p-Eigen significantly aid classification of Mild Cognitive Impairment (MCI) as well as the prediction of scores in a Delayed Recall memory task when compared to graph metrics derived from 1) standard registration-based seed ROI definitions, 2) totally data driven ROIs 3) a model based on standard demographics plus hippocampal volume as covariates and 4) Ward Clustering based data driven ROIs. In summary, p-Eigen incarnates a new

  4. Oblique along path toward structures at rear of parcel. Original ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Oblique along path toward structures at rear of parcel. Original skinny mosaic path along edge of structures was altered (delineation can be seen in concrete) path was widened with a newer mosaic to make access to the site safer. Structures (from right) edge of Round House (with "Spring Garden"), Pencil house, Shell House, School House, wood lattice is attached to chain-link fence along north (rear) property line. These structures were all damaged by the 1994 Northridge earthquake. Camera facing northeast. - Grandma Prisbrey's Bottle Village, 4595 Cochran Street, Simi Valley, Ventura County, CA

  5. Using natural beta emission for detecting concealed tobacco in parcels

    NASA Astrophysics Data System (ADS)

    Myers, Jeremy; Hussein, Esam M. A.

    2007-10-01

    It is suspected that postal systems are used for the illegal shipment of tobacco products to circumvent taxation and excise payments. This paper demonstrates that beta-particle emission from the potassium-40 contained in tobacco can be used to passively detect its presence in paperboard postal parcels. The same concept can be utilized for the detection of marijuana, whose leaves are also rich in 40K. The combination of high beta activity and a low weight is a good indicator of the presence of these two contraband materials.

  6. Ascent trajectory dispersion analysis

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The results of a Space Transportation System ascent trajectory dispersion analysis are documented. Critical trajectory parameter values useful for the definition of lightweight external tank insulation requirements are provided. This analysis was conducted using two of the critical missions specified for the Space Transportation System: a 28.5 deg inclination trajectory launched from the Eastern Test Range (ETR) and a Western Test Range (WTR) trajectory launched into a 104 deg orbital inclination.

  7. A Study of Shuttlecock's Trajectory in Badminton.

    PubMed

    Chen, Lung-Ming; Pan, Yi-Hsiang; Chen, Yung-Jen

    2009-01-01

    The main purpose of this study was to construct and validate a motion equation for the flight of the badminton and to find the relationship between the air resistance force and a shuttlecock's speed. This research method was based on motion laws of aerodynamics. It applied aerodynamic theories to construct motion equation of a shuttlecock's flying trajectory under the effects of gravitational force and air resistance force. The result showed that the motion equation of a shuttlecock's flight trajectory could be constructed by determining the terminal velocity. The predicted shuttlecock trajectory fitted the measured data fairly well. The results also revealed that the drag force was proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory. Finally, this study suggested that we could use a scientific approach to measure a shuttlecock's velocity objectively when testing the quality of shuttlecocks. And could be used to replace the traditional subjective method of the Badminton World Federation based on players' striking shuttlecocks, as well as applying research findings to improve professional knowledge of badminton player training. Key pointsThe motion equation of a shuttlecock's flying trajectory could be constructed by determining the terminal velocity in aerodynamics.Air drag force is proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory.

  8. Cerebellar Functional Parcellation Using Sparse Dictionary Learning Clustering

    PubMed Central

    Wang, Changqing; Kipping, Judy; Bao, Chenglong; Ji, Hui; Qiu, Anqi

    2016-01-01

    The human cerebellum has recently been discovered to contribute to cognition and emotion beyond the planning and execution of movement, suggesting its functional heterogeneity. We aimed to identify the functional parcellation of the cerebellum using information from resting-state functional magnetic resonance imaging (rs-fMRI). For this, we introduced a new data-driven decomposition-based functional parcellation algorithm, called Sparse Dictionary Learning Clustering (SDLC). SDLC integrates dictionary learning, sparse representation of rs-fMRI, and k-means clustering into one optimization problem. The dictionary is comprised of an over-complete set of time course signals, with which a sparse representation of rs-fMRI signals can be constructed. Cerebellar functional regions were then identified using k-means clustering based on the sparse representation of rs-fMRI signals. We solved SDLC using a multi-block hybrid proximal alternating method that guarantees strong convergence. We evaluated the reliability of SDLC and benchmarked its classification accuracy against other clustering techniques using simulated data. We then demonstrated that SDLC can identify biologically reasonable functional regions of the cerebellum as estimated by their cerebello-cortical functional connectivity. We further provided new insights into the cerebello-cortical functional organization in children. PMID:27199650

  9. 77 FR 42780 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... Regulatory Commission a Request of the United States Postal Service to Add Parcel Select Contract 5...

  10. 77 FR 42780 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY... Regulatory Commission a Request of the United States Postal Service to Add Parcel Select Contract 3...

  11. 77 FR 28410 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY... Commission a Request of the United States Postal Service to Add Parcel Select Contract 1 to...

  12. 77 FR 66193 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-02

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... the Postal Regulatory Commission a Request of the United States Postal Service To Add Parcel...

  13. 77 FR 42780 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service\\TM\\. ACTION: Notice. SUMMARY... Regulatory Commission a Request of the United States Postal Service to Add Parcel Select Contract 4...

  14. 76 FR 2930 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... ] Commission a Request of the United States Postal Service to Add Parcel Select Contract 1 to...

  15. 78 FR 56248 - Product Change-Parcel Select Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-12

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY... the Postal Regulatory Commission a Request of the United States Postal Service to Add Parcel...

  16. 15 CFR 740.12 - Gift parcels and humanitarian donations (GFT).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... destinations, no items controlled for chemical and biological weapons (CB), missile technology (MT), national... items intended for resale or reexport. (B) Eligible items. For all destinations, eligible items are food... in gift parcels. (iii) Frequency. (A) Except for gift parcels of food to Cuba, not more than one...

  17. 48 CFR 242.1404 - Shipments by parcel post or other classes of mail.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Shipments by parcel post or other classes of mail. 242.1404 Section 242.1404 Federal Acquisition Regulations System DEFENSE... SERVICES Traffic and Transportation Management 242.1404 Shipments by parcel post or other classes of mail....

  18. 48 CFR 242.1404 - Shipments by parcel post or other classes of mail.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Shipments by parcel post or other classes of mail. 242.1404 Section 242.1404 Federal Acquisition Regulations System DEFENSE... SERVICES Traffic and Transportation Management 242.1404 Shipments by parcel post or other classes of mail....

  19. 15 CFR 740.12 - Gift parcels and humanitarian donations (GFT).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...). The gift parcel must be provided free of charge to the donee. However, payment by the donee of any... countries permit the entry, duty-free, of gift parcels that conform to regulations regarding contents and... justification. (iv) Value. The combined total domestic retail value of all commodities and software in a...

  20. 39 CFR 320.7 - Suspension for advertisements accompanying parcels or periodicals.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Suspension for advertisements accompanying parcels... advertisements accompanying parcels or periodicals. (a) The operation of 39 U.S.C. 601(a) (1) through (6) and § 310.2(b) (1) through (6) of this chapter is suspended on all post routes for advertisements...

  1. Semi-supervised clustering for parcellating brain regions based on resting state fMRI data

    NASA Astrophysics Data System (ADS)

    Cheng, Hewei; Fan, Yong

    2014-03-01

    Many unsupervised clustering techniques have been adopted for parcellating brain regions of interest into functionally homogeneous subregions based on resting state fMRI data. However, the unsupervised clustering techniques are not able to take advantage of exiting knowledge of the functional neuroanatomy readily available from studies of cytoarchitectonic parcellation or meta-analysis of the literature. In this study, we propose a semi-supervised clustering method for parcellating amygdala into functionally homogeneous subregions based on resting state fMRI data. Particularly, the semi-supervised clustering is implemented under the framework of graph partitioning, and adopts prior information and spatial consistent constraints to obtain a spatially contiguous parcellation result. The graph partitioning problem is solved using an efficient algorithm similar to the well-known weighted kernel k-means algorithm. Our method has been validated for parcellating amygdala into 3 subregions based on resting state fMRI data of 28 subjects. The experiment results have demonstrated that the proposed method is more robust than unsupervised clustering and able to parcellate amygdala into centromedial, laterobasal, and superficial parts with improved functionally homogeneity compared with the cytoarchitectonic parcellation result. The validity of the parcellation results is also supported by distinctive functional and structural connectivity patterns of the subregions and high consistency between coactivation patterns derived from a meta-analysis and functional connectivity patterns of corresponding subregions.

  2. 76 FR 23749 - Intelligent Mail Package Barcode (IMpb) Implementation for Commercial Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ... tracking barcode on all commercial parcels, except Standard Mail parcels, claiming presort and destination entry pricing by January 2012; and to encourage use of unique tracking barcodes by providing free... Classification, U.S. Postal Service, 475 L'Enfant Plaza SW., Room 4446, Washington, DC 20260-5015. You...

  3. 76 FR 59504 - Intelligent Mail Package Barcode (IMpb) Implementation for Commercial Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-27

    ... unique tracking barcodes or IMpb. Mailers requiring an exception may direct their request to vice... Intelligent Mail unique tracking barcode on all commercial parcels, except Standard Mail parcels, claiming presort or destination entry pricing; to encourage use of IMpb unique tracking barcodes by providing...

  4. Tests of cortical parcellation based on white matter connectivity using diffusion tensor imaging.

    PubMed

    Gao, Yurui; Schilling, Kurt G; Stepniewska, Iwona; Plassard, Andrew J; Choe, Ann S; Li, Xia; Landman, Bennett A; Anderson, Adam W

    2017-02-22

    The cerebral cortex is conventionally divided into a number of domains based on cytoarchitectural features. Diffusion tensor imaging (DTI) enables noninvasive parcellation of the cortex based on white matter connectivity patterns. However, the correspondence between DTI-connectivity-based and cytoarchitectural parcellation has not been systematically established. In this study, we compared histological parcellation of New World monkey neocortex to DTI- connectivity-based classification and clustering in the same brains. First, we used supervised classification to parcellate parieto-frontal cortex based on DTI tractograms and the cytoarchitectural prior (obtained using Nissl staining). We performed both within and across sample classification, showing reasonable classification performance in both conditions. Second, we used unsupervised clustering to parcellate the cortex and compared the clusters to the cytoarchitectonic standard. We then explored the similarities and differences with several post-hoc analyses, highlighting underlying principles that drive the DTI-connectivity-based parcellation. The differences in parcellation between DTI-connectivity and Nissl histology probably represent both DTI's bias toward easily-tracked bundles and true differences between cytoarchitectural and connectivity defined domains. DTI tractograms appear to cluster more according to functional networks, rather than mapping directly onto cytoarchitectonic domains. Our results show that caution should be used when DTI-tractography classification, based on data from another brain, is used as a surrogate for cytoarchitectural parcellation.

  5. Robust brain parcellation using sparse representation on resting-state fMRI.

    PubMed

    Zhang, Yu; Caspers, Svenja; Fan, Lingzhong; Fan, Yong; Song, Ming; Liu, Cirong; Mo, Yin; Roski, Christian; Eickhoff, Simon; Amunts, Katrin; Jiang, Tianzi

    2015-11-01

    Resting-state fMRI (rs-fMRI) has been widely used to segregate the brain into individual modules based on the presence of distinct connectivity patterns. Many parcellation methods have been proposed for brain parcellation using rs-fMRI, but their results have been somewhat inconsistent, potentially due to various types of noise. In this study, we provide a robust parcellation method for rs-fMRI-based brain parcellation, which constructs a sparse similarity graph based on the sparse representation coefficients of each seed voxel and then uses spectral clustering to identify distinct modules. Both the local time-varying BOLD signals and whole-brain connectivity patterns may be used as features and yield similar parcellation results. The robustness of our method was tested on both simulated and real rs-fMRI datasets. In particular, on simulated rs-fMRI data, sparse representation achieved good performance across different noise levels, including high accuracy of parcellation and high robustness to noise. On real rs-fMRI data, stable parcellation of the medial frontal cortex (MFC) and parietal operculum (OP) were achieved on three different datasets, with high reproducibility within each dataset and high consistency across these results. Besides, the parcellation of MFC was little influenced by the degrees of spatial smoothing. Furthermore, the consistent parcellation of OP was also well corresponding to cytoarchitectonic subdivisions and known somatotopic organizations. Our results demonstrate a new promising approach to robust brain parcellation using resting-state fMRI by sparse representation.

  6. Externally mixed aerosol : simulation of ice nucleation in a parcel model

    NASA Astrophysics Data System (ADS)

    Anquetil-Deck, Candy; Hoose, Corinna; Conolly, Paul

    2014-05-01

    The effect of different aerosol (mineral dust, bacteria and soot) acting as immersion ice nuclei is investigated using ACPIM (AerosolCloud Precipitation Interaction Model) [1]. ACPIM is a powerful tool which can be used in two different ways. This box model can be, either, driven by experimental data (experiments carried out at the AIDA cloud chamber facility) or used as an air parcel in order to examine different ice nucleation parameterizations under specific conditions. This adiabatic air parcel model was employed for the simulation of a convective cloud. The study consists here in the investigation of how two externally mixed aerosols interact with one another. The initial study concentrates on mineral dust aerosol and biological aerosol without any background in order to fully understand the interaction between the different types of aerosol. Immersion freezing is described for the mineral dust aerosol by Niemand et al. 's parameterization [2], which was derived from laboratory studies in AIDA and is an extension of surface site density approach suggested by Connolly et al. [1]. Regarding bioaerosol, we introduce Hummel et al. 's parameterization [3] : f(in) = f(max)(1 - exp(- Ap *n(s)(T))) With an empirically fitted ice nucleation active site density n s based on AIDA measurements of Pseudomonas syringae bacteria [4]. This initial study is conducted for different proportion of each aerosol (the total number of aerosol being constant throughout all the simulation runs) at different vertical velocities. We then extented this study with different backgrounds (urban, marine, rural) in order to get a full picture. We found that there is not only a CCN competition but an IN competition as well. References : [1] Connolly, P. J., Möhler O., Field P. R., Saathoff H., Burgess, R., Choularton, T. and Gallagher, M., Atmos. Chem. Phys 9, 2805-2824 (2009). [2] Niemand, M., Möhler, O., Vogel B., Vogel, H., Hoose, C., Connolly, P., Klein, H., Bingemer, H., De

  7. The Impact of Using Item Parcels on ad hoc Goodness of Fit Indices in Confirmatory Factor Analysis: An Empirical Example.

    ERIC Educational Resources Information Center

    Takahashi, Tomone; Nasser, Fadia

    The Arabic version of I. G. Sarason's (1984) Reactions to Tests scale was used to examine the impact of using item parcels on ad hoc goodness of fit indices in confirmatory factor analysis. Item parcels with different numbers of items and different numbers of parcels per factor were used. Analyses were conducted on a sample of 420 tenth graders…

  8. Trajectories of Martian Habitability

    PubMed Central

    2014-01-01

    Abstract Beginning from two plausible starting points—an uninhabited or inhabited Mars—this paper discusses the possible trajectories of martian habitability over time. On an uninhabited Mars, the trajectories follow paths determined by the abundance of uninhabitable environments and uninhabited habitats. On an inhabited Mars, the addition of a third environment type, inhabited habitats, results in other trajectories, including ones where the planet remains inhabited today or others where planetary-scale life extinction occurs. By identifying different trajectories of habitability, corresponding hypotheses can be described that allow for the various trajectories to be disentangled and ultimately a determination of which trajectory Mars has taken and the changing relative abundance of its constituent environments. Key Words: Mars—Habitability—Liquid water—Planetary science. Astrobiology 14, 182–203. PMID:24506485

  9. PM2.5 chemical composition at a rural background site in Central Europe, including correlation and air mass back trajectory analysis

    NASA Astrophysics Data System (ADS)

    Schwarz, Jaroslav; Cusack, Michael; Karban, Jindřich; Chalupníčková, Eva; Havránek, Vladimír; Smolík, Jiří; Ždímal, Vladimír

    2016-07-01

    of fresh, local aerosol and aged, long-range transport aerosol. The influences of different air masses were also investigated. The lowest concentrations of PM2.5 were recorded under the influence of marine air masses from the NW, which were also marked by increased concentrations of marine aerosol. In contrast, the highest concentrations of PM2.5 and most major chemical components were measured during periods when continental easterly air masses were dominant.

  10. Optimization Of Simulated Trajectories

    NASA Technical Reports Server (NTRS)

    Brauer, Garry L.; Olson, David W.; Stevenson, Robert

    1989-01-01

    Program To Optimize Simulated Trajectories (POST) provides ability to target and optimize trajectories of point-mass powered or unpowered vehicle operating at or near rotating planet. Used successfully to solve wide variety of problems in mechanics of atmospheric flight and transfer between orbits. Generality of program demonstrated by its capability to simulate up to 900 distinct trajectory phases, including generalized models of planets and vehicles. VAX version written in FORTRAN 77 and CDC version in FORTRAN V.

  11. Ares I-X Best Estimated Trajectory Analysis and Results

    NASA Technical Reports Server (NTRS)

    Karlgaard, Christopher D.; Beck, Roger E.; Starr, Brett R.; Derry, Stephen D.; Brandon, Jay; Olds, Aaron D.

    2011-01-01

    The Ares I-X trajectory reconstruction produced best estimated trajectories of the flight test vehicle ascent through stage separation, and of the first and upper stage entries after separation. The trajectory reconstruction process combines on-board, ground-based, and atmospheric measurements to produce the trajectory estimates. The Ares I-X vehicle had a number of on-board and ground based sensors that were available, including inertial measurement units, radar, air-data, and weather balloons. However, due to problems with calibrations and/or data, not all of the sensor data were used. The trajectory estimate was generated using an Iterative Extended Kalman Filter algorithm, which is an industry standard processing algorithm for filtering and estimation applications. This paper describes the methodology and results of the trajectory reconstruction process, including flight data preprocessing and input uncertainties, trajectory estimation algorithms, output transformations, and comparisons with preflight predictions.

  12. Connectivity-based structural and functional parcellation of the human cortex using diffusion imaging and tractography

    PubMed Central

    Cloutman, Lauren L.; Lambon Ralph, Matthew A.

    2012-01-01

    The parcellation of the cortex via its anatomical properties has been an important research endeavor for over a century. To date, however, a universally accepted parcellation scheme for the human brain still remains elusive. In the current review, we explore the use of in vivo diffusion imaging and white matter tractography as a non-invasive method for the structural and functional parcellation of the human cerebral cortex, discussing the strengths and limitations of the current approaches. Cortical parcellation via white matter connectivity is based on the premise that, as connectional anatomy determines functional organization, it should be possible to segregate functionally-distinct cortical regions by identifying similarities and differences in connectivity profiles. Recent studies have provided initial evidence in support of the efficacy of this connectional parcellation methodology. Such investigations have identified distinct cortical subregions which correlate strongly with functional regions identified via fMRI and meta-analyses. Furthermore, a strong parallel between the cortical regions defined via tractographic and more traditional cytoarchitectonic parcellation methods has been observed. However, the degree of correspondence and relative functional importance of cytoarchitectonic- versus connectivity-derived parcellations still remains unclear. Diffusion tractography remains one of the only methods capable of visualizing the structural networks of the brain in vivo. As such, it is of vital importance to continue to improve the accuracy of the methodology and to extend its potential applications in the study of cognition in neurological health and disease. PMID:22952459

  13. A Distributed Trajectory-Oriented Approach to Managing Traffic Complexity

    NASA Technical Reports Server (NTRS)

    Idris, Husni; Wing, David J.; Vivona, Robert; Garcia-Chico, Jose-Luis

    2007-01-01

    In order to handle the expected increase in air traffic volume, the next generation air transportation system is moving towards a distributed control architecture, in which ground-based service providers such as controllers and traffic managers and air-based users such as pilots share responsibility for aircraft trajectory generation and management. While its architecture becomes more distributed, the goal of the Air Traffic Management (ATM) system remains to achieve objectives such as maintaining safety and efficiency. It is, therefore, critical to design appropriate control elements to ensure that aircraft and groundbased actions result in achieving these objectives without unduly restricting user-preferred trajectories. This paper presents a trajectory-oriented approach containing two such elements. One is a trajectory flexibility preservation function, by which aircraft plan their trajectories to preserve flexibility to accommodate unforeseen events. And the other is a trajectory constraint minimization function by which ground-based agents, in collaboration with air-based agents, impose just-enough restrictions on trajectories to achieve ATM objectives, such as separation assurance and flow management. The underlying hypothesis is that preserving trajectory flexibility of each individual aircraft naturally achieves the aggregate objective of avoiding excessive traffic complexity, and that trajectory flexibility is increased by minimizing constraints without jeopardizing the intended ATM objectives. The paper presents conceptually how the two functions operate in a distributed control architecture that includes self separation. The paper illustrates the concept through hypothetical scenarios involving conflict resolution and flow management. It presents a functional analysis of the interaction and information flow between the functions. It also presents an analytical framework for defining metrics and developing methods to preserve trajectory flexibility and

  14. Parcellation of the primary cerebral cortices based on local connectivity profiles

    PubMed Central

    Li, Qiaojun; Song, Ming; Fan, Lingzhong; Liu, Yong; Jiang, Tianzi

    2015-01-01

    Connectivity-based parcellation using diffusion MRI has been extensively used to parcellate subcortical areas and the association cortex. Connectivity profiles are vital for connectivity-based parcellation. Two categories of connectivity profiles are generally utilized, including global connectivity profiles, in which the connectivity information is from the seed to the whole brain, and long connectivity profiles, in which the connectivity information is from the seed to other brain regions after excluding the seed. However, whether global or long connectivity profiles should be applied in parcellating the primary cortex utilizing connectivity-based parcellation is unclear. Many sources of evidence have indicated that the primary cerebral cortices are composed of structurally and functionally distinct subregions. Because the primary cerebral cortices are rich in local anatomic hierarchical connections and possess high degree of local functional connectivity profiles, we proposed that local connectivity profiles, that is the connectivity information within a seed region of interest, might be used for parcellating the primary cerebral cortices. In this study, the global, long, and local connectivity profiles were separately used to parcellate the bilateral M1, A1, S1, and V1. We found that results using the three profiles were all quite consistent with reported cytoarchitectonic evidence. More importantly, the results using local connectivity profiles showed less inter-subject variability than the results using the other two, a finding which suggests that local connectivity profiles are superior to global and long connectivity profiles for parcellating the primary cerebral cortices. This also implies that, depending on the characteristics of specific areas of the cerebral cortex, different connectivity profiles may need to be adopted to parcellate different areas. PMID:25964743

  15. Complexity Science Applications to Dynamic Trajectory Management: Research Strategies

    NASA Technical Reports Server (NTRS)

    Sawhill, Bruce; Herriot, James; Holmes, Bruce J.; Alexandrov, Natalia

    2009-01-01

    The promise of the Next Generation Air Transportation System (NextGen) is strongly tied to the concept of trajectory-based operations in the national airspace system. Existing efforts to develop trajectory management concepts are largely focused on individual trajectories, optimized independently, then de-conflicted among each other, and individually re-optimized, as possible. The benefits in capacity, fuel, and time are valuable, though perhaps could be greater through alternative strategies. The concept of agent-based trajectories offers a strategy for automation of simultaneous multiple trajectory management. The anticipated result of the strategy would be dynamic management of multiple trajectories with interacting and interdependent outcomes that satisfy multiple, conflicting constraints. These constraints would include the business case for operators, the capacity case for the Air Navigation Service Provider (ANSP), and the environmental case for noise and emissions. The benefits in capacity, fuel, and time might be improved over those possible under individual trajectory management approaches. The proposed approach relies on computational agent-based modeling (ABM), combinatorial mathematics, as well as application of "traffic physics" concepts to the challenge, and modeling and simulation capabilities. The proposed strategy could support transforming air traffic control from managing individual aircraft behaviors to managing systemic behavior of air traffic in the NAS. A system built on the approach could provide the ability to know when regions of airspace approach being "full," that is, having non-viable local solution space for optimizing trajectories in advance.

  16. Distributed Traffic Complexity Management by Preserving Trajectory Flexibility

    NASA Technical Reports Server (NTRS)

    Idris, Husni; Vivona, Robert A.; Garcia-Chico, Jose-Luis; Wing, David J.

    2007-01-01

    In order to handle the expected increase in air traffic volume, the next generation air transportation system is moving towards a distributed control architecture, in which groundbased service providers such as controllers and traffic managers and air-based users such as pilots share responsibility for aircraft trajectory generation and management. This paper presents preliminary research investigating a distributed trajectory-oriented approach to manage traffic complexity, based on preserving trajectory flexibility. The underlying hypotheses are that preserving trajectory flexibility autonomously by aircraft naturally achieves the aggregate objective of avoiding excessive traffic complexity, and that trajectory flexibility is increased by collaboratively minimizing trajectory constraints without jeopardizing the intended air traffic management objectives. This paper presents an analytical framework in which flexibility is defined in terms of robustness and adaptability to disturbances and preliminary metrics are proposed that can be used to preserve trajectory flexibility. The hypothesized impacts are illustrated through analyzing a trajectory solution space in a simple scenario with only speed as a degree of freedom, and in constraint situations involving meeting multiple times of arrival and resolving conflicts.

  17. PANTHER. Trajectory Analysis

    SciTech Connect

    Rintoul, Mark Daniel; Wilson, Andrew T.; Valicka, Christopher G.; Kegelmeyer, W. Philip; Shead, Timothy M.; Newton, Benjamin D.; Czuchlewski, Kristina Rodriguez

    2015-09-01

    We want to organize a body of trajectories in order to identify, search for, classify and predict behavior among objects such as aircraft and ships. Existing compari- son functions such as the Fr'echet distance are computationally expensive and yield counterintuitive results in some cases. We propose an approach using feature vectors whose components represent succinctly the salient information in trajectories. These features incorporate basic information such as total distance traveled and distance be- tween start/stop points as well as geometric features related to the properties of the convex hull, trajectory curvature and general distance geometry. Additionally, these features can generally be mapped easily to behaviors of interest to humans that are searching large databases. Most of these geometric features are invariant under rigid transformation. We demonstrate the use of different subsets of these features to iden- tify trajectories similar to an exemplar, cluster a database of several hundred thousand trajectories, predict destination and apply unsupervised machine learning algorithms.

  18. Cirrus Parcel Model Comparison Project. Phase 1: The Critical Components to Simulate Cirrus Initiation Explicitly.

    NASA Astrophysics Data System (ADS)

    Lin, Ruei-Fong; O'C. Starr, David; Demott, Paul J.; Cotton, Richard; Sassen, Kenneth; Jensen, Eric; Kärcher, Bernd; Liu, Xiaohong

    2002-08-01

    laboratory studies, but each includes assumptions that can only be justified by further laboratory research. Consequently, it is not yet clear if the two approaches can be made consistent. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (0.2-1 m s1) at 60°C. The equilibrium assumption is commonly invoked in cirrus parcel models. The resulting difference in particle-size-dependent solution concentration of haze particles may significantly affect the ice particle formation rate during the initial nucleation interval. The uptake rate for water vapor excess by ice crystals is another key component regulating the total number of nucleated ice crystals. This rate, the product of particle number concentration and ice crystal diffusional growth rate, which is particularly sensitive to the deposition coefficient when ice particles are small, modulates the peak particle formation rate achieved in an air parcel and the duration of the active nucleation time period. The consequent differences in cloud microphysical properties, and thus cloud optical properties, between state-of-the-art models of ice crystal initiation are significant.Intermodel differences in the case of all-mode simulations are correspondingly greater than in the case of homogeneous nucleation acting alone. Definitive laboratory and atmospheric benchmark data are needed to improve the treatment of heterogeneous nucleation processes.

  19. Extraction of bioavailable contaminants from marine sediments: an approach to reducing toxicity using adsorbent parcels.

    PubMed

    Goodsir, Freya; Fisher, Tom T; Barry, Jon; Bolam, Thi; Nelson, Leah D; Rumney, Heather S; Brant, Jan L

    2013-07-15

    This paper demonstrates an approach to reducing acute toxicity in marine sediments using adsorbent parcels. Acute toxicity tests were carried using the marine amphipod Corophium volutator. Marine sediments were spiked with two know contaminants tributyltin and naphthalene and then treated with adsorbent parcels containing either amberlite XAD4 or activated carbon. Results showed that both types of adsorbent parcels were effective in reducing acute toxicity, not only within spiked sediments containing naphthalene and/or tributyltin, but also in an environmental field samples form an expected contaminated site. Adsorbent parcels such as these could provide a practical approach to remediate areas of contaminated sediment within marine environments. Furthermore adsorbents can be used as an identification tool for problematic contaminants using a toxicity identification evaluation approach.

  20. The dimensionality of defense-mechanism parcels in the Defense Style Questionnaire-40.

    PubMed

    Wilkinson, Wayne W; Ritchie, Timothy D

    2015-03-01

    The Defense Style Questionnaire-40 (DSQ-40; Andrews, Singh, & Bond, 1993) uses pairs of items to measure 20 individual defense mechanisms. In a statistical sense, these item pairs represent parcels and are subject to the standards of unidimensionality demanded of parcels in general. Using a 2-facet modeling approach (N = 672), the present study examined the dimensionality of the defense-mechanism parcels in the DSQ-40 and found that the majority of the parcels did not satisfy the criteria for unidimensionality. In addition, the original 3-factor model of defense styles was not tenable with the present data. Overall, the results suggest caution when attempting to assess individual defense mechanisms using the DSQ-40.

  1. 133. PARCEL HANDLING SPACE OF POST OFFICE BUILDING, LEVEL 72.5, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    133. PARCEL HANDLING SPACE OF POST OFFICE BUILDING, LEVEL 72.5, NORTH OF TRUCKING PASSAGE MAIL TRANSPORT AREA, VIEW TO NORTHWEST - Terminal Tower Building, Cleveland Union Terminal, 50 Public Square, Cleveland, Cuyahoga County, OH

  2. Guidance on EPA Concurrence in the Identification of Uncontaminated Parcels under CERCLA Section 120 (h)(4)

    EPA Pesticide Factsheets

    This memorandum addresses the approach EPA should use in determining whether to concur that a parcel has been properly identified by a military service as 'uncontaminated' and therefore transferrable pursuant to CERCLA Section 120 (h)(4).

  3. Hydropedological Assessments of Parcel-Level Infiltration in an Arid Urban Ecosystem

    EPA Science Inventory

    Soil morphology and correspondent hydrologic data can contribute to qualifying and quantifying urban soil suitability and capacity to cycle stormwater runoff. We put particular emphasis on the possibility that residential parcels may manage their own stormwater on pervious yard a...

  4. Hydropedological Assessments of Parcel-Level Infiltration in an Arid Urban Ecosystem

    EPA Science Inventory

    Soil morphology and correspondent hydrologic data can contribute to qualifying and quantifying urban soil suitability and capacity to cycle stormwater runoff. We put particular emphasis on the possibility that residential parcels may manage their own stormwater on pervious yard ...

  5. Gene–Environment Interactions on Growth Trajectories

    PubMed Central

    Wang, Shuang; Xiong, Wei; Ma, Weiping; Chanock, Stephen; Jedrychowski, Wieslaw; Wu, Rongling; Perera, Frederica P.

    2012-01-01

    It has been suggested that children with larger brains tend to perform better on IQ tests or cognitive function tests. Prenatal head growth and head growth in infancy are two crucial periods for subsequent intelligence. Studies have shown that environmental exposure to air pollutants during pregnancy is associated with fetal growth reduction, developmental delay, and reduced IQ. Meanwhile, genetic polymorphisms may modify the effect of environment on head growth. However, studies on gene–environment or gene–gene interactions on growth trajectories have been quite limited partly due to the difficulty to quantitatively measure interactions on growth trajectories. Moreover, it is known that assessing the significance of gene–environment or gene–gene interactions on cross-sectional outcomes empirically using the permutation procedures may bring substantial errors in the tests. We proposed a score that quantitatively measures interactions on growth trajectories and developed an algorithm with a parametric bootstrap procedure to empirically assess the significance of the interactions on growth trajectories under the likelihood framework. We also derived a Wald statistic to test for interactions on growth trajectories and compared it to the proposed parametric bootstrap procedure. Through extensive simulation studies, we demonstrated the feasibility and power of the proposed testing procedures. We applied our method to a real dataset with head circumference measures from birth to age 7 on a cohort currently being conducted by the Columbia Center for Children's Environmental Health (CCCEH) in Krakow, Poland, and identified several significant gene–environment interactions on head circumference growth trajectories. PMID:22311237

  6. Trajectory Browser Website

    NASA Technical Reports Server (NTRS)

    Foster, Cyrus; Jaroux, Belgacem A.

    2012-01-01

    The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center to be used for the preliminary assessment of trajectories to small-bodies and planets and for providing relevant launch date, time-of-flight and V requirements. The site hosts a database of transfer trajectories from Earth to asteroids and planets for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and delta V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies. The educational potential of the website is also recognized for academia and the public with regards to trajectory design, a field that has generally been poorly understood by the public. The website is currently hosted on NASA-internal URL http://trajbrowser.arc.nasa.gov/ with plans for a public release as soon as development is complete.

  7. Tractography-based Parcellation of the Human Middle Temporal Gyrus

    PubMed Central

    Xu, Jinping; Wang, Jiaojian; Fan, Lingzhong; Li, Hai; Zhang, Wen; Hu, Qingmao; Jiang, Tianzi

    2015-01-01

    The middle temporal gyrus (MTG) participates in a variety of functions, suggesting the existence of distinct functional subregions. In order to further delineate the functions of this brain area, we parcellated the MTG based on its distinct anatomical connectivity profiles and identified four distinct subregions, including the anterior (aMTG), middle (mMTG), posterior (pMTG), and sulcus (sMTG). Both the anatomical connectivity patterns and the resting-state functional connectivity patterns revealed distinct connectivity profiles for each subregion. The aMTG was primarily involved in the default mode network, sound recognition, and semantic retrieval. The mMTG was predominantly involved in the semantic memory and semantic control networks. The pMTG seems to be a part of the traditional sensory language area. The sMTG appears to be associated with decoding gaze direction and intelligible speech. Interestingly, the functional connectivity with Brodmann’s Area (BA) 40, BA 44, and BA 45 gradually increased from the anterior to the posterior MTG, a finding which indicated functional topographical organization as well as implying that language processing is functionally segregated in the MTG. These proposed subdivisions of the MTG and its functions contribute to understanding the complex functions of the MTG at the subregional level. PMID:26689815

  8. Calculation of Per Parcel Probability for Dud Bombs in Germany

    NASA Astrophysics Data System (ADS)

    Tavakkoli Sabour, S. M.; Agarius, J.; Sadidi, J.

    2014-10-01

    Unexploded aerial Bombs, also known as duds or unfused bombs, of the bombardments in the past wars remain explosive for decades after the war under the earth's surface threatening the civil activities especially if dredging works are involved. Interpretation of the aerial photos taken shortly after bombardments has been proven to be useful for finding the duds. Unfortunately, the reliability of this method is limited by some factors. The chance of finding a dud on an aerial photo depends strongly on the photography system, the size of the bomb and the landcover. On the other hand, exploded bombs are considerably better detectable on aerial photos and confidently represent the extent and density of a bombardment. Considering an empirical quota of unfused bombs, the expected number of duds can be calculated by the number of exploded bombs. This can help to have a better calculation of cost-risk ratio and to classify the areas for clearance. This article is about a method for calculation of a per parcel probability of dud bombs according to the distribution and density of exploded bombs. No similar work has been reported in this field by other authors.

  9. A Simple Parcel Method for Prediction of Cumulus Onset and Area-Averaged Cloud Amount over Heterogeneous Land Surfaces.

    NASA Astrophysics Data System (ADS)

    Wetzel, Peter J.

    1990-06-01

    The purpose of this note is to compare several methods for predicting the onset and quantitative amount of cloud cover over heterogeneous land surfaces. Among the methods tested are that of Wilde et al. (1985) and a new, simple parcel approach. Model comparison is accomplished by running each model using a series of six initial conditions from the Wangara experiment. Case days were chosen because they had relatively quiet synoptic conditions, and exhibited the formation of cumulus clouds from an initially mostly clear sky during the period of solar heating. Each model contains two or three free parameters that were systematically varied until the optimum agreement was reached between observed and predicted cloud amount. The single best run for each method was chosen based on the RMSE and coefficient of determination. The best runs are compared and plotted against the observations for the six case days.Results of these limited tests do not necessarily suggest the absolute degree of accuracy to which low cloud cover may be predicted. This is left for a future study. Rather, the focus is on the relative skill and flexibility of the various models. It is shown that parcel methods, in which surface air is lifted to its equilibrium level while being diluted by a defined amount of mixed layer air, produce substantially superior prediction of cloud amount, particularly during periods of rapid cloud onset when the mean boundary layer top is swiftly rising through a new-neutral layer. Pending, verification from independent datasets, it appears that an rms error in instantaneous cloud amount of ±10% may be achievable.

  10. Towards a Formal Semantics of Flight Plans and Trajectories

    NASA Technical Reports Server (NTRS)

    Hagen, George E.; Butler, Ricky W.

    2014-01-01

    In the National Airspace System, ight plans are often used only as a planning tool by air trac controllers and aircraft operators. These plans are implicitly translated into trajectories by the pilot or by the ight management system, and subsequently own by the aircraft. This translation process inevitably introduces di erences between the plan and the trajectory. However, given the current intended usage, exact correspondence between the plan and the trajectory is not needed. To achieve greater capacity and eciency, future air trac management concepts are being designed around the use of trajectories where predictability is extremely important. In this paper, a mathematical relationship between ight plans and trajectories is explored with the goal of making feasible, highly accurate predictions of future positions and velocities of aircraft. The goal here is to describe, in mathematically precise detail, a formal language of trajectories, whereby all receivers of the trajectory information will be able to arrive at precisely the same trajectory predication and to do this without having aircraft broadcast a large amount of data. Although even a four-dimensional ight plan is simple in structure, this paper will show that it is inherently ambiguous and will explore these issues in detail. In e ect, we propose that a rigorous semantics for ight plans can be developed and this will serve as an important stepping stone towards trajectory-based operations in the National Airspace System.

  11. MAVEN's Trajectory to Mars

    NASA Video Gallery

    This movie shows the cruise trajectory of NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission, which was launched on Nov. 18, 2013. It will arrive at Mars on Sept. 21, 2014, to explore th...

  12. A Formally Verified Conflict Detection Algorithm for Polynomial Trajectories

    NASA Technical Reports Server (NTRS)

    Narkawicz, Anthony; Munoz, Cesar

    2015-01-01

    In air traffic management, conflict detection algorithms are used to determine whether or not aircraft are predicted to lose horizontal and vertical separation minima within a time interval assuming a trajectory model. In the case of linear trajectories, conflict detection algorithms have been proposed that are both sound, i.e., they detect all conflicts, and complete, i.e., they do not present false alarms. In general, for arbitrary nonlinear trajectory models, it is possible to define detection algorithms that are either sound or complete, but not both. This paper considers the case of nonlinear aircraft trajectory models based on polynomial functions. In particular, it proposes a conflict detection algorithm that precisely determines whether, given a lookahead time, two aircraft flying polynomial trajectories are in conflict. That is, it has been formally verified that, assuming that the aircraft trajectories are modeled as polynomial functions, the proposed algorithm is both sound and complete.

  13. Automated Cooperative Trajectories

    NASA Technical Reports Server (NTRS)

    Hanson, Curt; Pahle, Joseph; Brown, Nelson

    2015-01-01

    This presentation is an overview of the Automated Cooperative Trajectories project. An introduction to the phenomena of wake vortices is given, along with a summary of past research into the possibility of extracting energy from the wake by flying close parallel trajectories. Challenges and barriers to adoption of civilian automatic wake surfing technology are identified. A hardware-in-the-loop simulation is described that will support future research. Finally, a roadmap for future research and technology transition is proposed.

  14. Optimum Three Impulse Trajectory Generator with Patched Conic Trajectory Model

    NASA Technical Reports Server (NTRS)

    Payne, M. H.; Pines, S.; Horsewood, J. L.

    1972-01-01

    Optimal multi-impulse trajectories were investigated as a nominal about which asymptotic expansion was used to obtain approximations of optimal low thrust trajectories. The work consisted of the analysis and description of an optimal 3-impulse trajectory program. A patched-conic trajectory model was specifically designed for compatibility with the subsequent addition of the low thrust expansion approximation.

  15. Departure Trajectory Synthesis and the Intercept Problem

    NASA Technical Reports Server (NTRS)

    Bolender, Michael A.; Slater, G. L.

    1997-01-01

    Two areas of the departure problem in air traffic control are discussed. The first topic is the generation of climb-out trajectories to a fix. The trajectories would be utilized by a scheduling algorithm to allocate runways, sequence the proposed departures, and assign a departure time. The second area is concerned with finding horizontal trajectories to merge aircraft from the TRACON to an open slot in the en-route environment. Solutions are presented for the intercept problem for two cases: (1) the aircraft is traveling at the speed of the aircraft in the jetway; (2) the merging aircraft has to accelerate to reach the speed of the aircraft in the en-route stream. An algorithm is given regarding the computation of a solution for the latter case. For the former, a set of equations is given that allows us to numerically solve for the coordinate where the merge will occur.

  16. Census parcels cropping system classification from multitemporal remote imagery: a proposed universal methodology.

    PubMed

    García-Torres, Luis; Caballero-Novella, Juan J; Gómez-Candón, David; Peña, José Manuel

    2015-01-01

    A procedure named CROPCLASS was developed to semi-automate census parcel crop assessment in any agricultural area using multitemporal remote images. For each area, CROPCLASS consists of a) a definition of census parcels through vector files in all of the images; b) the extraction of spectral bands (SB) and key vegetation index (VI) average values for each parcel and image; c) the conformation of a matrix data (MD) of the extracted information; d) the classification of MD decision trees (DT) and Structured Query Language (SQL) crop predictive model definition also based on preliminary land-use ground-truth work in a reduced number of parcels; and e) the implementation of predictive models to classify unidentified parcels land uses. The software named CROPCLASS-2.0 was developed to semi-automatically perform the described procedure in an economically feasible manner. The CROPCLASS methodology was validated using seven GeoEye-1 satellite images that were taken over the LaVentilla area (Southern Spain) from April to October 2010 at 3- to 4-week intervals. The studied region was visited every 3 weeks, identifying 12 crops and others land uses in 311 parcels. The DT training models for each cropping system were assessed at a 95% to 100% overall accuracy (OA) for each crop within its corresponding cropping systems. The DT training models that were used to directly identify the individual crops were assessed with 80.7% OA, with a user accuracy of approximately 80% or higher for most crops. Generally, the DT model accuracy was similar using the seven images that were taken at approximately one-month intervals or a set of three images that were taken during early spring, summer and autumn, or set of two images that were taken at about 2 to 3 months interval. The classification of the unidentified parcels for the individual crops was achieved with an OA of 79.5%.

  17. Census Parcels Cropping System Classification from Multitemporal Remote Imagery: A Proposed Universal Methodology

    PubMed Central

    García-Torres, Luis; Caballero-Novella, Juan J.; Gómez-Candón, David; Peña, José Manuel

    2015-01-01

    A procedure named CROPCLASS was developed to semi-automate census parcel crop assessment in any agricultural area using multitemporal remote images. For each area, CROPCLASS consists of a) a definition of census parcels through vector files in all of the images; b) the extraction of spectral bands (SB) and key vegetation index (VI) average values for each parcel and image; c) the conformation of a matrix data (MD) of the extracted information; d) the classification of MD decision trees (DT) and Structured Query Language (SQL) crop predictive model definition also based on preliminary land-use ground-truth work in a reduced number of parcels; and e) the implementation of predictive models to classify unidentified parcels land uses. The software named CROPCLASS-2.0 was developed to semi-automatically perform the described procedure in an economically feasible manner. The CROPCLASS methodology was validated using seven GeoEye-1 satellite images that were taken over the LaVentilla area (Southern Spain) from April to October 2010 at 3- to 4-week intervals. The studied region was visited every 3 weeks, identifying 12 crops and others land uses in 311 parcels. The DT training models for each cropping system were assessed at a 95% to 100% overall accuracy (OA) for each crop within its corresponding cropping systems. The DT training models that were used to directly identify the individual crops were assessed with 80.7% OA, with a user accuracy of approximately 80% or higher for most crops. Generally, the DT model accuracy was similar using the seven images that were taken at approximately one-month intervals or a set of three images that were taken during early spring, summer and autumn, or set of two images that were taken at about 2 to 3 months interval. The classification of the unidentified parcels for the individual crops was achieved with an OA of 79.5%. PMID:25689830

  18. Handling Trajectory Uncertainties for Airborne Conflict Management

    NASA Technical Reports Server (NTRS)

    Barhydt, Richard; Doble, Nathan A.; Karr, David; Palmer, Michael T.

    2005-01-01

    Airborne conflict management is an enabling capability for NASA's Distributed Air-Ground Traffic Management (DAG-TM) concept. DAGTM has the goal of significantly increasing capacity within the National Airspace System, while maintaining or improving safety. Under DAG-TM, autonomous aircraft maintain separation from each other and from managed aircraft unequipped for autonomous flight. NASA Langley Research Center has developed the Autonomous Operations Planner (AOP), an onboard decision support system that provides airborne conflict management (ACM) and strategic flight planning support for autonomous aircraft pilots. The AOP performs conflict detection, prevention, and resolution from nearby traffic aircraft and area hazards. Traffic trajectory information is assumed to be provided by Automatic Dependent Surveillance Broadcast (ADS-B). Reliable trajectory prediction is a key capability for providing effective ACM functions. Trajectory uncertainties due to environmental effects, differences in aircraft systems and performance, and unknown intent information lead to prediction errors that can adversely affect AOP performance. To accommodate these uncertainties, the AOP has been enhanced to create cross-track, vertical, and along-track buffers along the predicted trajectories of both ownship and traffic aircraft. These buffers will be structured based on prediction errors noted from previous simulations such as a recent Joint Experiment between NASA Ames and Langley Research Centers and from other outside studies. Currently defined ADS-B parameters related to navigation capability, trajectory type, and path conformance will be used to support the algorithms that generate the buffers.

  19. Constructing 4D infant cortical surface atlases based on dynamic developmental trajectories of the cortex.

    PubMed

    Li, Gang; Wang, Li; Shi, Feng; Lin, Weili; Shen, Dinggang

    2014-01-01

    Cortical surface atlases play an increasingly important role for analysis, visualization, and comparison of results across different neuroimaging studies. As the first two years of life is the most dynamic period of postnatal structural and functional development of the highly-folded cerebral cortex, longitudinal (4D) cortical surface atlases for the infant brains during this period is highly desired yet still lacking for early brain development studies. In this paper, we construct the first longitudinal (4D) cortical surface atlases for the dynamic developing infant cortical structures at 1, 3, 6, 9, 12, 18 and 24 months of age, based on 202 serial MRI scans from 35 healthy infants. To ensure longitudinal consistency and unbiasedness of the 4D infant cortical surface atlases, we first compute the within-subject mean cortical folding geometries by groupwise registration of longitudinal surfaces of each infant. Then we establish intersubject cortical correspondences by groupwise registration of the within-subject mean cortical folding geometries of all infants. More importantly, for the first time, we further parcellate the 4D infant surface atlases into developmentally and functionally distinctive regions based solely on the dynamic developmental trajectories of the cortical thickness, by using the spectral clustering method. Specifically, to deal with the problem that each infant has different number of scans, we first compute the within-subject affinity matrix of vertices' cortical thickness trajectories of each infant, and then we use the averaged affinity matrix of all infants for parcellation. Our constructed 4D infant cortical surface atlases with developmental trajectories based parcellation will greatly facilitate the surface-based analysis of dynamic brain development in infants.

  20. The fastest evolutionary trajectory

    PubMed Central

    Traulsen, Arne; Iwasa, Yoh; Nowak, Martin A.

    2008-01-01

    Given two mutants, A and B, separated by n mutational steps, what is the evolutionary trajectory which allows a homogeneous population of A to reach B in the shortest time? We show that the optimum evolutionary trajectory (fitness landscape) has the property that the relative fitness increase between any two consecutive steps is constant. Hence, the optimum fitness landscape between A and B is given by an exponential function. Our result is precise for small mutation rates and excluding back mutations. We discuss deviations for large mutation rates and including back mutations. For very large mutation rates, the optimum fitness landscape is flat and has a single peak at type B. PMID:17900629

  1. [Winter wheat area estimation with MODIS-NDVI time series based on parcel].

    PubMed

    Li, Le; Zhang, Jin-shui; Zhu, Wen-quan; Hu, Tan-gao; Hou, Dong

    2011-05-01

    Several attributes of MODIS (moderate resolution imaging spectrometer) data, especially the short temporal intervals and the global coverage, provide an extremely efficient way to map cropland and monitor its seasonal change. However, the reliability of their measurement results is challenged because of the limited spatial resolution. The parcel data has clear geo-location and obvious boundary information of cropland. Also, the spectral differences and the complexity of mixed pixels are weak in parcels. All of these make that area estimation based on parcels presents more advantage than on pixels. In the present study, winter wheat area estimation based on MODIS-NDVI time series has been performed with the support of cultivated land parcel in Tongzhou, Beijing. In order to extract the regional winter wheat acreage, multiple regression methods were used to simulate the stable regression relationship between MODIS-NDVI time series data and TM samples in parcels. Through this way, the consistency of the extraction results from MODIS and TM can stably reach up to 96% when the amount of samples accounts for 15% of the whole area. The results shows that the use of parcel data can effectively improve the error in recognition results in MODIS-NDVI based multi-series data caused by the low spatial resolution. Therefore, with combination of moderate and low resolution data, the winter wheat area estimation became available in large-scale region which lacks completed medium resolution images or has images covered with clouds. Meanwhile, it carried out the preliminary experiments for other crop area estimation.

  2. Patched Conic Trajectory Code

    NASA Technical Reports Server (NTRS)

    Park, Brooke Anderson; Wright, Henry

    2012-01-01

    PatCon code was developed to help mission designers run trade studies on launch and arrival times for any given planet. Initially developed in Fortran, the required inputs included launch date, arrival date, and other orbital parameters of the launch planet and arrival planets at the given dates. These parameters include the position of the planets, the eccentricity, semi-major axes, argument of periapsis, ascending node, and inclination of the planets. With these inputs, a patched conic approximation is used to determine the trajectory. The patched conic approximation divides the planetary mission into three parts: (1) the departure phase, in which the two relevant bodies are Earth and the spacecraft, and where the trajectory is a departure hyperbola with Earth at the focus; (2) the cruise phase, in which the two bodies are the Sun and the spacecraft, and where the trajectory is a transfer ellipse with the Sun at the focus; and (3) the arrival phase, in which the two bodies are the target planet and the spacecraft, where the trajectory is an arrival hyperbola with the planet as the focus.

  3. Mission objectives and trajectories

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The present state of the knowledge of asteroids was assessed to identify mission and target priorities for planning asteroidal flights in the 1980's and beyond. Mission objectives, mission analysis, trajectory studies, and cost analysis are discussed. A bibliography of reports and technical memoranda is included.

  4. Trajectory structures and transport

    SciTech Connect

    Vlad, Madalina; Spineanu, Florin

    2004-11-01

    The special problem of transport in two-dimensional divergence-free stochastic velocity fields is studied by developing a statistical approach, the nested subensemble method. The nonlinear process of trapping determined by such fields generates trajectory structures whose statistical characteristics are determined. These structures strongly influence the transport.

  5. Cirrus Parcel Model Comparison Project. Phase 1; The Critical Components to Simulate Cirrus Initiation Explicitly

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, David OC; DeMott, Paul J.; Cotton, Richard; Sassen, Kenneth; Jensen, Eric; Einaudi, Franco (Technical Monitor)

    2001-01-01

    clear if the two approaches can be made consistent. Large haze particles may deviate considerably from equilibrium size in moderate to strong updrafts (20-100 centimeters per second) at -60 C when the commonly invoked equilibrium assumption is lifted. The resulting difference in particle-size- dependent solution concentration of haze particles may significantly affect the ice particle formation rate during the initial nucleation interval. The uptake rate for water vapor excess by ice crystals is another key component regulating the total number of nucleated ice crystals. This rate, the product of particle number concentration and ice crystal diffusional growth rate, which is particularly sensitive to the deposition coefficient when ice particles are small, modulates the peak particle formation rate achieved in an air parcel and the duration of the active nucleation time period. The effects of heterogeneous nucleation are most pronounced in weak updraft situations. Vapor competition by the heterogeneously nucleated ice crystals may limit the achieved ice supersaturation and thus suppresses the contribution of homogeneous nucleation. Correspondingly, ice crystal number density is markedly reduced. Definitive laboratory and atmospheric benchmark data are needed for the heterogeneous nucleation process. Inter-model differences are correspondingly greater than in the case of the homogeneous nucleation process acting alone.

  6. Analysis of major air pollutants and submicron particles in New York City and Long Island

    NASA Astrophysics Data System (ADS)

    Masiol, M.; Hopke, P. K.; Felton, H. D.; Frank, B. P.; Rattigan, O. V.; Wurth, M. J.; LaDuke, G. H.

    2017-01-01

    A year-long sampling campaign of major air pollutants and submicron particle number size distributions was conducted at two sites taken as representative of city-wide air quality in New York City and Long Island, respectively. A number of species were quantified with hourly time resolution, including particle number concentrations in 6 size ranges (20-30 nm, 30-50 nm, 50-70 nm, 70-100 nm, 100-200 nm, and >200 nm), nitrogen oxides, sulfur dioxide, ozone, carbon monoxide, methane, non-methane hydrocarbons, PM2.5 mass concentration and some PM major components (sulfate, organic and elemental carbon). Hourly concentrations of primary and secondary organic carbon were estimated using the EC tracer method. Data were matched with weather parameters and air parcel back-trajectories. A series of tools were thus applied to: (i) study the seasonal, weekly, diurnal cycles of pollutants; (ii) investigate the relationships amongst pollutants through correlation and lagged correlation analyses; (iii) depict the role of atmospheric photochemical processes; (iv) examine the location of the potential sources by mean of conditional bivariate probability function analysis and (v) investigate the role of regional transport of air masses to the concentrations of analyzed species. Results indicate that concentrations of NOx, SO2, CO, non-methane hydrocarbons, primary OC and EC are predominantly determined by local sources, but are also affected by regional transports of polluted air masses. On the contrary, the transport of continental polluted air masses has a main effect in raising the concentrations of secondary PM2.5 (sulfate and secondary organic carbon). By providing direct information on the concentrations and trends of key pollutants and submicron particle number concentrations, this study finally enables some general considerations about air quality status and atmospheric processes over the New York City metropolitan area.

  7. GraSP: Geodesic Graph-based Segmentation With Shape Priors for the Functional Parcellation of the Cortex

    PubMed Central

    Honnorat, N.; Eavani, H.; Satterthwaite, T. D.; Gur, R. E.; Gur, R. C.; Davatzikos, C.

    2014-01-01

    Resting-state functional MRI is a powerful technique for mapping the functional organization of the human brain. However, for many types of connectivity analysis, high-resolution voxelwise analyses are computationally infeasible and dimensionality reduction is typically used to limit the number of network nodes. Most commonly, network nodes are defined using standard anatomic atlases that do not align well with functional neuroanatomy or regions of interest covering a small portion of the cortex. Data-driven parcellation methods seek to overcome such limitations, but existing approaches are highly dependent on initialization procedures and produce spatially fragmented parcels or overly isotropic parcels that are unlikely to be biologically grounded. In this paper, we propose a novel graph-based parcellation method that relies on a discrete Markov Random Field framework. The spatial connectedness of the parcels is explicitly enforced by shape priors. The shape of the parcels is adapted to underlying data through the use of functional geodesic distances. Our method is initialization-free and rapidly segments the cortex in a single optimization. The performance of the method was assessed using a large developmental cohort of more than 850 subjects. Compared to two prevalent parcellation methods, our approach provides superior reproducibility for a similar data fit. Furthermore, compared to other methods, it avoids incoherent parcels. Finally, the method’s utility is demonstrated through its ability to detect strong brain developmental effects that are only weakly observed using other methods. PMID:25462796

  8. GraSP: geodesic Graph-based Segmentation with Shape Priors for the functional parcellation of the cortex.

    PubMed

    Honnorat, N; Eavani, H; Satterthwaite, T D; Gur, R E; Gur, R C; Davatzikos, C

    2015-02-01

    Resting-state functional MRI is a powerful technique for mapping the functional organization of the human brain. However, for many types of connectivity analysis, high-resolution voxelwise analyses are computationally infeasible and dimensionality reduction is typically used to limit the number of network nodes. Most commonly, network nodes are defined using standard anatomic atlases that do not align well with functional neuroanatomy or regions of interest covering a small portion of the cortex. Data-driven parcellation methods seek to overcome such limitations, but existing approaches are highly dependent on initialization procedures and produce spatially fragmented parcels or overly isotropic parcels that are unlikely to be biologically grounded. In this paper, we propose a novel graph-based parcellation method that relies on a discrete Markov Random Field framework. The spatial connectedness of the parcels is explicitly enforced by shape priors. The shape of the parcels is adapted to underlying data through the use of functional geodesic distances. Our method is initialization-free and rapidly segments the cortex in a single optimization. The performance of the method was assessed using a large developmental cohort of more than 850 subjects. Compared to two prevalent parcellation methods, our approach provides superior reproducibility for a similar data fit. Furthermore, compared to other methods, it avoids incoherent parcels. Finally, the method's utility is demonstrated through its ability to detect strong brain developmental effects that are only weakly observed using other methods.

  9. 25 CFR 166.303 - Can more than one parcel of Indian land be combined into one permit?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Can more than one parcel of Indian land be combined into one permit? 166.303 Section 166.303 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR LAND AND WATER GRAZING PERMITS Land and Operations Management § 166.303 Can more than one parcel of...

  10. A note on using alpha and stratified alpha to estimate the reliability of a test composed of item parcels.

    PubMed

    Rae, Gordon

    2008-11-01

    Several authors have suggested that prior to conducting a confirmatory factor analysis it may be useful to group items into a smaller number of item 'parcels' or 'testlets'. The present paper mathematically shows that coefficient alpha based on these parcel scores will only exceed alpha based on the entire set of items if W, the ratio of the average covariance of items between parcels to the average covariance of items within parcels, is greater than unity. If W is less than unity, however, and errors of measurement are uncorrelated, then stratified alpha will be a better lower bound to the reliability of a measure than the other two coefficients. Stratified alpha are also equal to the true reliability of a test when items within parcels are essentially tau-equivalent if one assumes that errors of measurement are not correlated.

  11. High Altitude Venus Operations Concept Trajectory Design, Modeling and Simulation

    NASA Technical Reports Server (NTRS)

    Lugo, Rafael A.; Ozoroski, Thomas A.; Van Norman, John W.; Arney, Dale C.; Dec, John A.; Jones, Christopher A.; Zumwalt, Carlie H.

    2015-01-01

    A trajectory design and analysis that describes aerocapture, entry, descent, and inflation of manned and unmanned High Altitude Venus Operation Concept (HAVOC) lighter-than-air missions is presented. Mission motivation, concept of operations, and notional entry vehicle designs are presented. The initial trajectory design space is analyzed and discussed before investigating specific trajectories that are deemed representative of a feasible Venus mission. Under the project assumptions, while the high-mass crewed mission will require further research into aerodynamic decelerator technology, it was determined that the unmanned robotic mission is feasible using current technology.

  12. A Study of Shuttlecock’s Trajectory in Badminton

    PubMed Central

    Chen, Lung-Ming; Pan, Yi-Hsiang; Chen, Yung-Jen

    2009-01-01

    The main purpose of this study was to construct and validate a motion equation for the flight of the badminton and to find the relationship between the air resistance force and a shuttlecock’s speed. This research method was based on motion laws of aerodynamics. It applied aerodynamic theories to construct motion equation of a shuttlecock’s flying trajectory under the effects of gravitational force and air resistance force. The result showed that the motion equation of a shuttlecock’s flight trajectory could be constructed by determining the terminal velocity. The predicted shuttlecock trajectory fitted the measured data fairly well. The results also revealed that the drag force was proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory. Finally, this study suggested that we could use a scientific approach to measure a shuttlecock’s velocity objectively when testing the quality of shuttlecocks. And could be used to replace the traditional subjective method of the Badminton World Federation based on players’ striking shuttlecocks, as well as applying research findings to improve professional knowledge of badminton player training. Key points The motion equation of a shuttlecock’s flying trajectory could be constructed by determining the terminal velocity in aerodynamics. Air drag force is proportional to the square of a shuttlecock velocity. Furthermore, the angle and strength of a stroke could influence trajectory. PMID:24149609

  13. TrackTable Trajectory Analysis

    SciTech Connect

    Wilson, Andrew T.

    2014-08-25

    Tracktable is designed for analysis and rendering of the trajectories of moving objects such as planes, trains, automobiles and ships. Its purpose is to operate on large sets of trajectories (millions) to help a user detect, analyze and display patterns. It will also be used to disseminate trajectory research results from Sandia's PANTHER Grand Challenge LDRD.

  14. Trajectory Code Studies, 1987

    SciTech Connect

    Poukey, J.W.

    1988-01-01

    The trajectory code TRAJ has been used extensively to study nonimmersed foilless electron diodes. The basic goal of the research is to design low-emittance injectors for electron linacs and propagation experiments. Systems studied during 1987 include Delphi, Recirc, and Troll. We also discuss a partly successful attempt to extend the same techniques to high currents (tens of kA). 7 refs., 30 figs.

  15. Surrealistic Bohm Trajectories

    NASA Astrophysics Data System (ADS)

    Englert, Berthold-Georg; Scully, Marian O.; Süssmann, Georg; Walther, Herbert

    1992-12-01

    A study of interferometers with one-bit which-way detectors demonstrates that the trajectories, which David Bohm invented in his attempt at a realistic interpretation of quantum mechanics, are in fact surrealistic, because they may be macroscopically at variance with the observed track of the particle. We consider a two-slit interferometer and an incomplete Stern-Gerlach interferometer, and propose an experimentum crucis based on the latter.

  16. 78 FR 65392 - Product Change-Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-31

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice... Return Service Contract 5 to Competitive Product List. Documents are available at www.prc.gov ,...

  17. 76 FR 13000 - Transfer of Commercial First-Class Mail Parcels to Competitive Product List

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-09

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Transfer of Commercial First-Class Mail Parcels to Competitive Product List AGENCY: Postal Service.\\TM\\ ACTION: Notice. SUMMARY: The Postal Service hereby provides notice that it has filed a request with the Postal...

  18. Vineyard parcel identification from Worldview-2 images using object-based classification model

    NASA Astrophysics Data System (ADS)

    Sertel, Elif; Yay, Irmak

    2014-01-01

    Accurate identification of spatial distribution and characteristics of vineyard parcels is an important task for the effective management of vineyard areas, precision viticulture, and farmer registries. This study aimed to develop rule sets to be used in object-based classification of Worldview-2 satellite images to accurately delineate the boundaries of vineyards having different plantation styles. Multilevel segmentation was applied to Worldview-2 images to create different sizes of image objects representing different land cover categories with respect to scale parameter. Texture analysis and several new spectral indices were applied to objects at different segmentation levels to accurately classify land cover classes of forest, cultivated areas, harvested areas, impervious, bareland, and vineyards. A specific attention was given to vineyard class to identify vine areas at the parcel level considering their different plantation styles. The results illustrated that the combined usage of a newly developed decision tree and image segmentation during the object-based classification process could provide highly accurate results for the identification of vineyard parcels. Linearly planted vineyards could be classified with 100% producer's accuracy due to their regular textural characteristics, whereas regular gridwise and irregular gridwise (distributed) vineyard parcels could be classified with 94.87% producer's accuracy in this research.

  19. Land use planning and surface heat island formation: A parcel-based radiation flux approach

    NASA Astrophysics Data System (ADS)

    Stone, Brian; Norman, John M.

    This article presents a study of residential parcel design and surface heat island formation in a major metropolitan region of the southeastern United States. Through the integration of high-resolution multispectral data (10 m) with property tax records for over 100,000 single-family residential parcels in the Atlanta, Georgia, metropolitan region, the influence of the size and material composition of residential land use on an indicator of surface heat island formation is reported. In contrast to previous work on the urban heat island, this study derives a parcel-based indicator of surface warming to permit the impact of land use planning regulations governing the density and design of development on the excess surface flux of heat energy to be measured. The results of this study suggest that the contribution of individual land parcels to regional surface heat island formation could be reduced by approximately 40% through the adoption of specific land use planning policies, such as zoning and subdivision regulations, and with no modifications to the size or albedo of the residential structure.

  20. 75 FR 74755 - Product Change-Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Return Service Negotiated Service Agreement AGENCY: Postal Service TM . ACTION: Notice. SUMMARY: Postal Service notice of filing of a request with the Postal Regulatory Commission to add...

  1. OPTIMAL AIRCRAFT TRAJECTORIES FOR SPECIFIED RANGE

    NASA Technical Reports Server (NTRS)

    Lee, H.

    1994-01-01

    For an aircraft operating over a fixed range, the operating costs are basically a sum of fuel cost and time cost. While minimum fuel and minimum time trajectories are relatively easy to calculate, the determination of a minimum cost trajectory can be a complex undertaking. This computer program was developed to optimize trajectories with respect to a cost function based on a weighted sum of fuel cost and time cost. As a research tool, the program could be used to study various characteristics of optimum trajectories and their comparison to standard trajectories. It might also be used to generate a model for the development of an airborne trajectory optimization system. The program could be incorporated into an airline flight planning system, with optimum flight plans determined at takeoff time for the prevailing flight conditions. The use of trajectory optimization could significantly reduce the cost for a given aircraft mission. The algorithm incorporated in the program assumes that a trajectory consists of climb, cruise, and descent segments. The optimization of each segment is not done independently, as in classical procedures, but is performed in a manner which accounts for interaction between the segments. This is accomplished by the application of optimal control theory. The climb and descent profiles are generated by integrating a set of kinematic and dynamic equations, where the total energy of the aircraft is the independent variable. At each energy level of the climb and descent profiles, the air speed and power setting necessary for an optimal trajectory are determined. The variational Hamiltonian of the problem consists of the rate of change of cost with respect to total energy and a term dependent on the adjoint variable, which is identical to the optimum cruise cost at a specified altitude. This variable uniquely specifies the optimal cruise energy, cruise altitude, cruise Mach number, and, indirectly, the climb and descent profiles. If the optimum

  2. 76 FR 77856 - International Mail Price Change for Inbound Air Parcel Post

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... CONTACT: Stephen L. Sharfman, General Counsel, at (202) 789-6820 (case-related information) or Docket... Postal Service was eligible based on inflation increases and other factors.'' Notice at 2-3. In the... service bonus eligibility and submission of annual inflation information from the Consumer Price Index...

  3. Assessing levels of POPs in air over the South Atlantic Ocean off the coast of South America.

    PubMed

    Pegoraro, César N; Harner, Tom; Su, Ky; Chiappero, Malisa S

    2016-11-15

    The occurrence of persistent organic pollutants (POPs) in the atmosphere of the near-coast South Atlantic Ocean was studied. Air samples were collected using a high-volume air sampler (filter and polyurethane foam) on board the Argentinean research cruise R/V Puerto Deseado (CONICET). Samples were analyzed for 50 polychlorinated biphenyl (PCBs), 22 organochlorine pesticides (OCPs) and 14 polybrominated diphenyl ethers (PBDEs). These POPs classes showed a trend of decreasing levels from near-shore to open ocean sites. OCPs and PCBs were in the same order of magnitude (2.71-87.1pg/m(3) and 9.56-130pg/m(3), respectively) while PBDEs levels were significantly lower (0.69-2.58pg/m(3)). Dichlorodiphenyltrichloroethanes (DDTs), endosulfans, chlordanes, hexachlorocyclohexanes (HCHs) and heptachlors were between 0.20 and 17.8pg/m(3), while drines and hexachlorobenzene (HCB) were at lower levels (0.28-3.71pg/m(3)). The most frequently detected PCBs were congeners 32, 28, 44, 52, 95, representing >50% of the total. The PBDEs congener pattern was dominated by congener 209 (70%), followed by 47 and 99 (16% and 7%, respectively). Air parcel back trajectories for the study period provided few insights as trajectories mainly stemmed from the open ocean with limited inputs from continental sources. These results indicate that the concentration of POPs (namely PCBs, OCPs, and PBDEs) in air remain elevated in the near-shore environment and then drop-off substantially beyond a distance of about 400km. This has implications for the loading of POPs and delivery to the marine environment in the near coastal zone.

  4. Trajectory Optimization: OTIS 4

    NASA Technical Reports Server (NTRS)

    Riehl, John P.; Sjauw, Waldy K.; Falck, Robert D.; Paris, Stephen W.

    2010-01-01

    The latest release of the Optimal Trajectories by Implicit Simulation (OTIS4) allows users to simulate and optimize aerospace vehicle trajectories. With OTIS4, one can seamlessly generate optimal trajectories and parametric vehicle designs simultaneously. New features also allow OTIS4 to solve non-aerospace continuous time optimal control problems. The inputs and outputs of OTIS4 have been updated extensively from previous versions. Inputs now make use of objectoriented constructs, including one called a metastring. Metastrings use a greatly improved calculator and common nomenclature to reduce the user s workload. They allow for more flexibility in specifying vehicle physical models, boundary conditions, and path constraints. The OTIS4 calculator supports common mathematical functions, Boolean operations, and conditional statements. This allows users to define their own variables for use as outputs, constraints, or objective functions. The user-defined outputs can directly interface with other programs, such as spreadsheets, plotting packages, and visualization programs. Internally, OTIS4 has more explicit and implicit integration procedures, including high-order collocation methods, the pseudo-spectral method, and several variations of multiple shooting. Users may switch easily between the various methods. Several unique numerical techniques such as automated variable scaling and implicit integration grid refinement, support the integration methods. OTIS4 is also significantly more user friendly than previous versions. The installation process is nearly identical on various platforms, including Microsoft Windows, Apple OS X, and Linux operating systems. Cross-platform scripts also help make the execution of OTIS and post-processing of data easier. OTIS4 is supplied free by NASA and is subject to ITAR (International Traffic in Arms Regulations) restrictions. Users must have a Fortran compiler, and a Python interpreter is highly recommended.

  5. Titan Explorer Entry, Descent and Landing Trajectory Design

    NASA Technical Reports Server (NTRS)

    Fisher, Jody L.; Lindberg, Robert E.; Lockwood, Mary Kae

    2006-01-01

    The Titan Explorer mission concept includes an orbiter, entry probe and inflatable airship designed to take remote and in-situ measurements of Titan's atmosphere. A modified entry, descent and landing trajectory at Titan that incorporates mid-air airship inflation (under a parachute) and separation is developed and examined for Titan Explorer. The feasibility of mid-air inflation and deployment of an airship under a parachute is determined by implementing and validating an airship buoyancy and inflation model in the trajectory simulation program, Program to Optimize Simulated Trajectories II (POST2). A nominal POST2 trajectory simulation case study is generated which examines different descent scenarios by varying airship inflation duration, orientation, and separation. The buoyancy model incorporation into POST2 is new to the software and may be used in future trajectory simulations. Each case from the nominal POST2 trajectory case study simulates a successful separation between the parachute and airship systems with sufficient velocity change as to alter their paths to avoid collision throughout their descent. The airship and heatshield also separate acceptably with a minimum distance of separation from the parachute system of 1.5 km. This analysis shows the feasibility of airship inflation on a parachute for different orientations, airship separation at various inflation times, and preparation for level-flight at Titan.

  6. Trajectories in parallel optics.

    PubMed

    Klapp, Iftach; Sochen, Nir; Mendlovic, David

    2011-10-01

    In our previous work we showed the ability to improve the optical system's matrix condition by optical design, thereby improving its robustness to noise. It was shown that by using singular value decomposition, a target point-spread function (PSF) matrix can be defined for an auxiliary optical system, which works parallel to the original system to achieve such an improvement. In this paper, after briefly introducing the all optics implementation of the auxiliary system, we show a method to decompose the target PSF matrix. This is done through a series of shifted responses of auxiliary optics (named trajectories), where a complicated hardware filter is replaced by postprocessing. This process manipulates the pixel confined PSF response of simple auxiliary optics, which in turn creates an auxiliary system with the required PSF matrix. This method is simulated on two space variant systems and reduces their system condition number from 18,598 to 197 and from 87,640 to 5.75, respectively. We perform a study of the latter result and show significant improvement in image restoration performance, in comparison to a system without auxiliary optics and to other previously suggested hybrid solutions. Image restoration results show that in a range of low signal-to-noise ratio values, the trajectories method gives a significant advantage over alternative approaches. A third space invariant study case is explored only briefly, and we present a significant improvement in the matrix condition number from 1.9160e+013 to 34,526.

  7. Computational Approaches to Simulation and Optimization of Global Aircraft Trajectories

    NASA Technical Reports Server (NTRS)

    Ng, Hok Kwan; Sridhar, Banavar

    2016-01-01

    This study examines three possible approaches to improving the speed in generating wind-optimal routes for air traffic at the national or global level. They are: (a) using the resources of a supercomputer, (b) running the computations on multiple commercially available computers and (c) implementing those same algorithms into NASAs Future ATM Concepts Evaluation Tool (FACET) and compares those to a standard implementation run on a single CPU. Wind-optimal aircraft trajectories are computed using global air traffic schedules. The run time and wait time on the supercomputer for trajectory optimization using various numbers of CPUs ranging from 80 to 10,240 units are compared with the total computational time for running the same computation on a single desktop computer and on multiple commercially available computers for potential computational enhancement through parallel processing on the computer clusters. This study also re-implements the trajectory optimization algorithm for further reduction of computational time through algorithm modifications and integrates that with FACET to facilitate the use of the new features which calculate time-optimal routes between worldwide airport pairs in a wind field for use with existing FACET applications. The implementations of trajectory optimization algorithms use MATLAB, Python, and Java programming languages. The performance evaluations are done by comparing their computational efficiencies and based on the potential application of optimized trajectories. The paper shows that in the absence of special privileges on a supercomputer, a cluster of commercially available computers provides a feasible approach for national and global air traffic system studies.

  8. Probabilistic Modeling of Aircraft Trajectories for Dynamic Separation Volumes

    NASA Technical Reports Server (NTRS)

    Lewis, Timothy A.

    2016-01-01

    With a proliferation of new and unconventional vehicles and operations expected in the future, the ab initio airspace design will require new approaches to trajectory prediction for separation assurance and other air traffic management functions. This paper presents an approach to probabilistic modeling of the trajectory of an aircraft when its intent is unknown. The approach uses a set of feature functions to constrain a maximum entropy probability distribution based on a set of observed aircraft trajectories. This model can be used to sample new aircraft trajectories to form an ensemble reflecting the variability in an aircraft's intent. The model learning process ensures that the variability in this ensemble reflects the behavior observed in the original data set. Computational examples are presented.

  9. Periodic billiard trajectories in polygons: generating mechanisms

    NASA Astrophysics Data System (ADS)

    Vorobets, Ya B.; Gal'perin, G. A.; Stepin, Anatolii M.

    1992-06-01

    CONTENTSIntroduction §1. Billiard trajectories in a plane domain §2. Fagnano's problem. Mechanical interpretations of periodic trajectories in triangles §3. An extremal property of billiard trajectories. Birkhoff's theorem. The non-existence of a unified construction of periodic trajectories in obtuse triangles §4. 'Perpendicular' trajectories in obtuse triangles of special shape §5. 'Perpendicular' trajectories in rational polygons and polyhedra §6. Stable trajectories §7. Stable perpendicular trajectories §8. Isolated trajectories §9. Isolated trajectories in acute and obtuse triangles. The bifurcation diagram of isolated trajectories (a 'hang-glider' configuration) §10. The density of F-triangles in a neighbourhood of (0, 0) §11. Generalization of the construction of isolated trajectories in obtuse triangles §12. Stable and unstable billiard trajectories in plane Weyl chambers §13. A criterion for the stability of periodic trajectories in a regular hexagonConclusionReferences

  10. Ares I-X Best Estimated Trajectory and Comparison with Pre-Flight Predictions

    NASA Technical Reports Server (NTRS)

    Karlgaard, Christopher D.; Beck, Roger E.; Derry, Stephen D.; Brandon, Jay M.; Starr, Brett R.; Tartabini, Paul V.; Olds, Aaron D.

    2011-01-01

    The Ares I-X trajectory reconstruction produced best estimated trajectories of the flight test vehicle ascent through stage separation, and of the first and upper stage entries after separation. The trajectory reconstruction process combines on-board, ground-based, and atmospheric measurements to produce the trajectory estimates. The Ares I-X vehicle had a number of on-board and ground based sensors that were available, including inertial measurement units, radar, air- data, and weather balloons. However, due to problems with calibrations and/or data, not all of the sensor data were used. The trajectory estimate was generated using an Iterative Extended Kalman Filter algorithm, which is an industry standard processing algorithm for filtering and estimation applications. This paper describes the methodology and results of the trajectory reconstruction process, including flight data preprocessing and input uncertainties, trajectory estimation algorithms, output transformations, and comparisons with preflight predictions.

  11. Predictive Capabilities of a Relaxation Model for Parcel-Based Granular Flow Simulations

    NASA Astrophysics Data System (ADS)

    Radl, Stefan; Sundaresan, Sankaran

    2011-11-01

    Parcel-based methods have a great potential to reduce the computational cost of particle simulations for dense flows. Here we investigate a relaxation model, similar to that of Bhatnagar-Gross-Krook (BGK), when applied to such a parcel-based simulation method. Specifically, we have chosen the simulation methodology initially proposed by Patankar and Joseph, and combined it with the relaxation model published by O'Rourke and Snider. We show that a relaxation model is key to correctly predicting macroscopic flow features, e.g., the scattering pattern of a granular jet impinging on a flat surface, studied experimentally by Cheng et al.. Simple shear flow simulations reveal that calculation of the locally-averaged velocity is a critical ingredient to correctly predict streaming and collisional stresses. SR acknowledges the support of the Austrian Science Foundation through the Erwin-Schroedinger fellowship J-3072.

  12. Calculating Trajectories And Orbits

    NASA Technical Reports Server (NTRS)

    Alderson, Daniel J.; Brady, Franklyn H.; Breckheimer, Peter J.; Campbell, James K.; Christensen, Carl S.; Collier, James B.; Ekelund, John E.; Ellis, Jordan; Goltz, Gene L.; Hintz, Gerarld R.; Legerton, Victor N.; Mccreary, Faith A.; Mitchell, Robert T.; Mottinger, Neil A.; Moultrie, Benjamin A.; Moyer, Theodore D.; Rinker, Sheryl L.; Ryne, Mark S.; Stavert, L. Robert; Sunseri, Richard F.

    1989-01-01

    Double-Precision Trajectory Analysis Program, DPTRAJ, and Orbit Determination Program, ODP, developed and improved over years to provide highly reliable and accurate navigation capability for deep-space missions like Voyager. Each collection of programs working together to provide desired computational results. DPTRAJ, ODP, and supporting utility programs capable of handling massive amounts of data and performing various numerical calculations required for solving navigation problems associated with planetary fly-by and lander missions. Used extensively in support of NASA's Voyager project. DPTRAJ-ODP available in two machine versions. UNIVAC version, NPO-15586, written in FORTRAN V, SFTRAN, and ASSEMBLER. VAX/VMS version, NPO-17201, written in FORTRAN V, SFTRAN, PL/1 and ASSEMBLER.

  13. Using geometrical, textural, and contextual information of land parcels for classification of detailed urban land use

    USGS Publications Warehouse

    Wu, S.-S.; Qiu, X.; Usery, E.L.; Wang, L.

    2009-01-01

    Detailed urban land use data are important to government officials, researchers, and businesspeople for a variety of purposes. This article presents an approach to classifying detailed urban land use based on geometrical, textural, and contextual information of land parcels. An area of 6 by 14 km in Austin, Texas, with land parcel boundaries delineated by the Travis Central Appraisal District of Travis County, Texas, is tested for the approach. We derive fifty parcel attributes from relevant geographic information system (GIS) and remote sensing data and use them to discriminate among nine urban land uses: single family, multifamily, commercial, office, industrial, civic, open space, transportation, and undeveloped. Half of the 33,025 parcels in the study area are used as training data for land use classification and the other half are used as testing data for accuracy assessment. The best result with a decision tree classification algorithm has an overall accuracy of 96 percent and a kappa coefficient of 0.78, and two naive, baseline models based on the majority rule and the spatial autocorrelation rule have overall accuracy of 89 percent and 79 percent, respectively. The algorithm is relatively good at classifying single-family, multifamily, commercial, open space, and undeveloped land uses and relatively poor at classifying office, industrial, civic, and transportation land uses. The most important attributes for land use classification are the geometrical attributes, particularly those related to building areas. Next are the contextual attributes, particularly those relevant to the spatial relationship between buildings, then the textural attributes, particularly the semivariance texture statistic from 0.61-m resolution images.

  14. Interim Project Results: United Parcel Service's Second-Generation Hybrid-Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2012-01-01

    This fact sheet describes the performance evaluation of United Parcel Service's second-generation hybrid-electric delivery vans. The Fleet Test and Evaluation Team at the National Renewable Energy Laboratory (NREL) is evaluating the 18-month, in-service performance of 11 of these vans along with 11 comparable conventional diesel vans operating in Minneapolis, Minnesota. As a complement to the field study, the team recently completed fuel economy and emissions testing at NREL's Renewable Fuels and Lubricants (ReFUEL) laboratory.

  15. Jettison Engineering Trajectory Tool

    NASA Technical Reports Server (NTRS)

    Zaczek, Mariusz; Walter, Patrick; Pascucci, Joseph; Armstrong, Phyllis; Hallbick, Patricia; Morgan, Randal; Cooney, James

    2013-01-01

    The Jettison Engineering Trajectory Tool (JETT) performs the jettison analysis function for any orbiting asset. It provides a method to compute the relative trajectories between an orbiting asset and any jettisoned item (intentional or unintentional) or sublimating particles generated by fluid dumps to assess whether an object is safe to jettison, or if there is a risk with an item that was inadvertently lost overboard. The main concern is the interaction and possible recontact of the jettisoned object with an asset. This supports the analysis that jettisoned items will safely clear the vehicle, ensuring no collisions. The software will reduce the jettison analysis task from one that could take days to complete to one that can be completed in hours, with an analysis that is more comprehensive than the previous method. It provides the ability to define the jettison operation relative to International Space Station (ISS) structure, and provides 2D and 3D plotting capability to allow an analyst to perform a subjective clearance assessment with ISS structures. The developers followed the SMP to create the code and all supporting documentation. The code makes extensive use of the object-oriented format of Java and, in addition, the Model-View-Controller architecture was used in the organization of the code, allowing each piece to be independent of updates to the other pieces. The model category is for maintaining data entered by the user and generated by the analysis. The view category provides capabilities for data entry and displaying all or a portion of the analysis data in tabular, 2D, and 3D representation. The controller category allows for handling events that affect the model or view(s). The JETT utilizes orbital mechanics with complex algorithms. Since JETT is written in JAVA, it is essentially platform-independent.

  16. Spatio-temporal topological relationships between land parcels in cadastral database

    NASA Astrophysics Data System (ADS)

    Song, W.; Zhang, F.

    2014-04-01

    There are complex spatio-temporal relationships among cadastral entities. Cadastral spatio-temporal data model should not only describe the data structure of cadastral objects, but also express cadastral spatio-temporal relationships between cadastral objects. In the past, many experts and scholars have proposed a variety of cadastral spatio-temporal data models, but few of them concentrated on the representation of spatiotemporal relationships and few of them make systematic studies on spatiotemporal relationships between cadastral objects. The studies on spatio-temporal topological relationships are not abundant. In the paper, we initially review current approaches to the studies of spatio-temporal topological relationships, and argue that spatio-temporal topological relation is the combination of temporal topology on the time dimension and spatial topology on the spatial dimension. Subsequently, we discuss and develop an integrated representation of spatio-temporal topological relationships within a 3-dimensional temporal space. In the end, based on the semantics of spatiotemporal changes between land parcels, we conclude the possible spatio-temporal topological relations between land parcels, which provide the theoretical basis for creating, updating and maintaining of land parcels in the cadastral database.

  17. Trajectory optimization and guidance for an aerospace plane

    NASA Technical Reports Server (NTRS)

    Mease, Kenneth D.; Vanburen, Mark A.

    1989-01-01

    The first step in the approach to developing guidance laws for a horizontal take-off, air breathing single-stage-to-orbit vehicle is to characterize the minimum-fuel ascent trajectories. The capability to generate constrained, minimum fuel ascent trajectories for a single-stage-to-orbit vehicle was developed. A key component of this capability is the general purpose trajectory optimization program OTIS. The pre-production version, OTIS 0.96 was installed and run on a Convex C-1. A propulsion model was developed covering the entire flight envelope of a single-stage-to-orbit vehicle. Three separate propulsion modes, corresponding to an after burning turbojet, a ramjet and a scramjet, are used in the air breathing propulsion phase. The Generic Hypersonic Aerodynamic Model Example aerodynamic model of a hypersonic air breathing single-stage-to-orbit vehicle was obtained and implemented. Preliminary results pertaining to the effects of variations in acceleration constraints, available thrust level and fuel specific impulse on the shape of the minimum-fuel ascent trajectories were obtained. The results show that, if the air breathing engines are sized for acceleration to orbital velocity, it is the acceleration constraint rather than the dynamic pressure constraint that is active during ascent.

  18. On the Trajectories of Projectiles Depicted in Early Ballistic Woodcuts

    ERIC Educational Resources Information Center

    Stewart, Sean M.

    2012-01-01

    Motivated by quaint woodcut depictions often found in many late 16th and 17th century ballistic manuals of cannonballs fired in air, a comparison of their shapes with those calculated for the classic case of a projectile moving in a linear resisting medium is made. In considering the asymmetrical nature of such trajectories, the initial launch…

  19. Ballistic projectile trajectory determining system

    DOEpatents

    Karr, T.J.

    1997-05-20

    A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile. 8 figs.

  20. Ballistic projectile trajectory determining system

    DOEpatents

    Karr, Thomas J.

    1997-01-01

    A computer controlled system determines the three-dimensional trajectory of a ballistic projectile. To initialize the system, predictions of state parameters for a ballistic projectile are received at an estimator. The estimator uses the predictions of the state parameters to estimate first trajectory characteristics of the ballistic projectile. A single stationary monocular sensor then observes the actual first trajectory characteristics of the ballistic projectile. A comparator generates an error value related to the predicted state parameters by comparing the estimated first trajectory characteristics of the ballistic projectile with the observed first trajectory characteristics of the ballistic projectile. If the error value is equal to or greater than a selected limit, the predictions of the state parameters are adjusted. New estimates for the trajectory characteristics of the ballistic projectile are made and are then compared with actual observed trajectory characteristics. This process is repeated until the error value is less than the selected limit. Once the error value is less than the selected limit, a calculator calculates trajectory characteristics such a the origin and destination of the ballistic projectile.

  1. Lunar Cube Transfer Trajectory Options

    NASA Technical Reports Server (NTRS)

    Folta, David; Dichmann, Donald James; Clark, Pamela E.; Haapala, Amanda; Howell, Kathleen

    2015-01-01

    Numerous Earth-Moon trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many trajectory options can b e considered which have a wide range of transfer duration, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO) geostationary transfer orbits (GTO) and higher energy direct lunar transfer and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory.

  2. Lunar Cube Transfer Trajectory Options

    NASA Technical Reports Server (NTRS)

    Folta, David; Dichmann, Donald J.; Clark, Pamela; Haapala, Amanda; Howell, Kathleen

    2015-01-01

    Numerous Earth-Moon trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many trajectory options can be considered which have a wide range of transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO), geostationary transfer orbits (GTO), and higher energy direct lunar transfers and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory.

  3. Optimal solar sail planetocentric trajectories

    NASA Technical Reports Server (NTRS)

    Sackett, L. L.

    1977-01-01

    The analysis of solar sail planetocentric optimal trajectory problem is described. A computer program was produced to calculate optimal trajectories for a limited performance analysis. A square sail model is included and some consideration is given to a heliogyro sail model. Orbit to a subescape point and orbit to orbit transfer are considered. Trajectories about the four inner planets can be calculated and shadowing, oblateness, and solar motion may be included. Equinoctial orbital elements are used to avoid the classical singularities, and the method of averaging is applied to increase computational speed. Solution of the two-point boundary value problem which arises from the application of optimization theory is accomplished with a Newton procedure. Time optimal trajectories are emphasized, but a penalty function has been considered to prevent trajectories which intersect a planet's surface.

  4. Three-dimensional Simulations of the Mean Air Transport During the 1997 Forest Fires in Kalimantan, Indonesia Using a Mesoscale Numerical Model

    NASA Astrophysics Data System (ADS)

    Roswintiarti, O.; Raman, S.

    - This paper describes the meteorological processes responsible for the mean transport of air pollutants during the ENSO-related forest fires in Kalimantan, Indonesia from 00 UTC 21 September to 00 UTC 25 September, 1997. The Fifth Generation of the Pennsylvania State University-National Center for Atmospheric Research (PSU-NCAR) Mesoscale Model (MM5) is used to simulate three-dimensional winds at 6-hourly intervals. A nonhydrostatic version of the model is run using two nested grids with horizontal resolutions of 45 km and 15 km. From the simulated wind fields, the backward and forward trajectories of the air parcel are investigated using the Vis5D model.The results indicate that the large-scale subsidence over Indonesia, the southwest monsoon low-level flows (2-8 m s-1), and the shallow planetary boundary layer height (400-800 m) play a key role in the transport of air pollutants from Kalimantan to Malaysia, Singapore and Brunei.

  5. Survey and Method for Determination of Trajectory Predictor Requirements

    NASA Technical Reports Server (NTRS)

    Rentas, Tamika L.; Green, Steven M.; Cate, Karen Tung

    2009-01-01

    A survey of air-traffic-management researchers, representing a broad range of automation applications, was conducted to document trajectory-predictor requirements for future decision-support systems. Results indicated that the researchers were unable to articulate a basic set of trajectory-prediction requirements for their automation concepts. Survey responses showed the need to establish a process to help developers determine the trajectory-predictor-performance requirements for their concepts. Two methods for determining trajectory-predictor requirements are introduced. A fast-time simulation method is discussed that captures the sensitivity of a concept to the performance of its trajectory-prediction capability. A characterization method is proposed to provide quicker, yet less precise results, based on analysis and simulation to characterize the trajectory-prediction errors associated with key modeling options for a specific concept. Concept developers can then identify the relative sizes of errors associated with key modeling options, and qualitatively determine which options lead to significant errors. The characterization method is demonstrated for a case study involving future airport surface traffic management automation. Of the top four sources of error, results indicated that the error associated with accelerations to and from turn speeds was unacceptable, the error associated with the turn path model was acceptable, and the error associated with taxi-speed estimation was of concern and needed a higher fidelity concept simulation to obtain a more precise result

  6. A Final Approach Trajectory Model for Current Operations

    NASA Technical Reports Server (NTRS)

    Gong, Chester; Sadovsky, Alexander

    2010-01-01

    Predicting accurate trajectories with limited intent information is a challenge faced by air traffic management decision support tools in operation today. One such tool is the FAA's Terminal Proximity Alert system which is intended to assist controllers in maintaining safe separation of arrival aircraft during final approach. In an effort to improve the performance of such tools, two final approach trajectory models are proposed; one based on polynomial interpolation, the other on the Fourier transform. These models were tested against actual traffic data and used to study effects of the key final approach trajectory modeling parameters of wind, aircraft type, and weight class, on trajectory prediction accuracy. Using only the limited intent data available to today's ATM system, both the polynomial interpolation and Fourier transform models showed improved trajectory prediction accuracy over a baseline dead reckoning model. Analysis of actual arrival traffic showed that this improved trajectory prediction accuracy leads to improved inter-arrival separation prediction accuracy for longer look ahead times. The difference in mean inter-arrival separation prediction error between the Fourier transform and dead reckoning models was 0.2 nmi for a look ahead time of 120 sec, a 33 percent improvement, with a corresponding 32 percent improvement in standard deviation.

  7. Parcellation of the cingulate cortex at rest and during tasks: a meta-analytic clustering and experimental study.

    PubMed

    Torta, Diana M E; Costa, Tommaso; Duca, Sergio; Fox, Peter T; Cauda, Franco

    2013-01-01

    Anatomical, morphological, and histological data have consistently shown that the cingulate cortex can be divided into four main regions. However, less is known about parcellations of the cingulate cortex when involved in active tasks. Here, we aimed at comparing how the pattern of clusterization of the cingulate cortex changes across different levels of task complexity. We parcellated the cingulate cortex using the results of a meta-analytic study and of three experimental studies. The experimental studies, which included two active tasks and a resting state protocol, were used to control the results obtained with the meta-analytic parcellation. We explored the meta-analytic parcellation by applying a meta-analytic clustering (MaC) to papers retrieved from the BrainMap database. The MaC is a meta-analytic connectivity driven parcellation technique recently developed by our group which allowed us to parcellate the cingulate cortex on the basis of its pattern of co-activations during active tasks. The MaC results indicated that the cingulate cortex can be parcellated into three clusters. These clusters covered different percentages of the cingulate parenchyma and had a different density of foci, with the first cluster being more densely connected. The control experiments showed different clusterization results, suggesting that the co-activations of the cingulate cortex are highly dependent on the task that is tested. Our results highlight the importance of the cingulate cortex as a hub, which modifies its pattern of co-activations depending on the task requests and on the level of task complexity. The neurobiological meaning of these results is discussed.

  8. Capture Conditions for Merging Trajectory Segments to Model Realistic Aircraft Descents

    NASA Technical Reports Server (NTRS)

    Zhao, Yiyuan; Slattery, Rhonda A.

    1996-01-01

    A typical commercial aircraft trajectory consists of a series of flight segments. An aircraft switches from one segment to another when certain specified variables reach their desired values. Trajectory synthesis for air traffic control automation must be consistent with practical pilot procedures. We examine capture conditions for merging trajectory segments to model commercial aircraft descent in trajectory synthesis. These conditions translate into bounds on measurements of atmospheric wind, pressure, and temperature. They also define ranges of thrust and drag feasible for a descent trajectory. Capture conditions are derived for the Center-TRACON Automation System developed at NASA Ames Research Center for automated air traffic control. Various uses of capture conditions are discussed. A Boeing 727-200 aircraft is used to provide numerical examples of capture conditions.

  9. Flight test trajectory control analysis

    NASA Technical Reports Server (NTRS)

    Walker, R.; Gupta, N.

    1983-01-01

    Recent extensions to optimal control theory applied to meaningful linear models with sufficiently flexible software tools provide powerful techniques for designing flight test trajectory controllers (FTTCs). This report describes the principal steps for systematic development of flight trajectory controllers, which can be summarized as planning, modeling, designing, and validating a trajectory controller. The techniques have been kept as general as possible and should apply to a wide range of problems where quantities must be computed and displayed to a pilot to improve pilot effectiveness and to reduce workload and fatigue. To illustrate the approach, a detailed trajectory guidance law is developed and demonstrated for the F-15 aircraft flying the zoom-and-pushover maneuver.

  10. Galileo's Trajectory with Mild Resistance

    ERIC Educational Resources Information Center

    Groetsch, C. W.

    2012-01-01

    An aspect of Galileo's classical trajectory that persists in a simple resistance model is noted. The resistive model provides a case study for the classroom analysis of limiting behaviour of an implicitly defined function. (Contains 1 note.)

  11. ASTP (SA-210) Launch vehicle operational flight trajectory. Part 3: Final documentation

    NASA Technical Reports Server (NTRS)

    Carter, A. B.; Klug, G. W.; Williams, N. W.

    1975-01-01

    Trajectory data are presented for a nominal and two launch window trajectory simulations. These trajectories are designed to insert a manned Apollo spacecraft into a 150/167 km. (81/90 n. mi.) earth orbit inclined at 51.78 degrees for rendezvous with a Soyuz spacecraft, which will be orbiting at approximately 225 km. (121.5 n. mi.). The launch window allocation defined for this launch is 500 pounds of S-IVB stage propellant. The launch window opening trajectory simulation depicts the earliest launch time deviation from a planar flight launch which conforms to this constraint. The launch window closing trajectory simulation was developed for the more stringent Air Force Eastern Test Range (AFETR) flight azimuth restriction of 37.4 degrees east-of-north. These trajectories enclose a 12.09 minute launch window, pertinent features of which are provided in a tabulation. Planar flight data are included for mid-window reference.

  12. Physical work and strain involved in manual sorting of postal parcels.

    PubMed

    Louhevaara, V; Hakola, T; Ollila, H

    1990-09-01

    A field study was conducted to assess cardiorespiratory and musculoskeletal stress and strain and work output during manual sorting of postal parcels, and to detect the effects of parcel sorting on the maximal muscle strength and endurance. The volunteer subjects comprised 32 healthy male sorters with mean (+/- s.d.) age of 34 +/- 7 years at five different sorting sites. Each subject was studied during one evening work shift. During the shift of 391 +/- 46 min the subjects manually sorted 1173 +/- 630 parcels and walked 4.7 +/- 2.3 km with and without the load. While sorting, heart rate was 101 +/- 18 beats min-1. In the heaviest tasks the oxygen consumption was 1.2 +/- 0.41 min-1, and no elevated blood lactate concentrations were found. Work postures in which the back was bent forward averaged 24% of the time for sorting. The overall cardiorespiratory rating and local ratings of perceived exertion for arms, back, and legs did not exceed the 'somewhat strong' level during the work shift. The maximal static strength both for the right and left hand-grip muscles was, on average, 3% lower (p less than 0.05) after the work shift than before the shift. No significant differences were found in the static or dynamic endurance times for the hand-grip muscles when the results obtained after the work shift were compared to the baseline values. At sorting centres the stress and strain on the cardiorespiratory and musculoskeletal system was evaluated to remain within acceptable limits for healthy male sorters.

  13. 3-D Cytoarchitectonic parcellation of human orbitofrontal cortex. Correlation with postmortem MRI

    PubMed Central

    Uylings, Harry B.M.; Sanz-Arigita, Ernesto J.; de Vos, Koos; Pool, Chris W.; Evers, Paul; Rajkowska, Grazyna

    2010-01-01

    The orbitofrontal cortex (OFC) is located on the basal surface of the frontal lobe and is distinguished by its unique anatomical and functional features. Clinical and postmortem studies suggest the involvement of the orbitofrontal cortex in psychiatric disorders. However, the exact parcellation of this cortical region is still a matter of debate. Therefore, the goal of this study is to provide a detailed description of the extent of borders of individual orbitofrontal cortical areas using cytoarchitectonic criteria in a large sample of human brains, which could be applied by independent neuroanatomists. To make this microscopic parcellation useful to neuroimaging studies, magnetic resonance images of postmortem brains in the coronal plane were collected prior to the preparation of coronal histological sections from the same brains. A complete series of coronal sections from 6 normal human brains and partial sections from the frontal cortex of 21 normal human brains were stained with general histological and immunohistochemical methods specific for different cell-types, These sections were examined microscopically by two independent neuroanatomists (HBMU and GR) to achieve reproducible delineations. After the borders were determined, the tissue sections were superimposed on corresponding MR images. Based on our cytoarchitectonical criteria, Brodmann's areas 47 and 11 were included in the human orbitofrontal cortex. Area 47 was further subdivided into three medial (located on the medial, anterior and posterior orbital gyri) and two lateral (located on the lateral orbital gyrus) subareas. In addition, we observed an anterior-posterior gradient in the cytoarchitecture of areas 11 and 47. The transverse orbital sulcus corresponds roughly to the transition between the subregions of the anterior and posterior OFC. Finally, the present delineation is contrasted with an overview of the different published nomenclatures for the OFC parcellation. PMID:20538437

  14. Green infrastructure retrofits on residential parcels: Ecohydrologic modeling for stormwater design

    NASA Astrophysics Data System (ADS)

    Miles, B.; Band, L. E.

    2014-12-01

    To meet water quality goals stormwater utilities and not-for-profit watershed organizations in the U.S. are working with citizens to design and implement green infrastructure on residential land. Green infrastructure, as an alternative and complement to traditional (grey) stormwater infrastructure, has the potential to contribute to multiple ecosystem benefits including stormwater volume reduction, carbon sequestration, urban heat island mitigation, and to provide amenities to residents. However, in small (1-10-km2) medium-density urban watersheds with heterogeneous land cover it is unclear whether stormwater retrofits on residential parcels significantly contributes to reduce stormwater volume at the watershed scale. In this paper, we seek to improve understanding of how small-scale redistribution of water at the parcel scale as part of green infrastructure implementation affects urban water budgets and stormwater volume across spatial scales. As study sites we use two medium-density headwater watersheds in Baltimore, MD and Durham, NC. We develop ecohydrology modeling experiments to evaluate the effectiveness of redirecting residential rooftop runoff to un-altered pervious surfaces and to engineered rain gardens to reduce stormwater runoff. As baselines for these experiments, we performed field surveys of residential rooftop hydrologic connectivity to adjacent impervious surfaces, and found low rates of connectivity. Through simulations of pervasive adoption of downspout disconnection to un-altered pervious areas or to rain garden stormwater control measures (SCM) in these catchments, we find that most parcel-scale changes in stormwater fate are attenuated at larger spatial scales and that neither SCM alone is likely to provide significant changes in streamflow at the watershed scale.

  15. Automated individual-level parcellation of Broca's region based on functional connectivity.

    PubMed

    Jakobsen, Estrid; Liem, Franziskus; Klados, Manousos A; Bayrak, Şeyma; Petrides, Michael; Margulies, Daniel S

    2016-09-30

    Broca's region can be subdivided into its constituent areas 44 and 45 based on established differences in connectivity to superior temporal and inferior parietal regions. The current study builds on our previous work manually parcellating Broca's area on the individual-level by applying these anatomical criteria to functional connectivity data. Here we present an automated observer-independent and anatomy-informed parcellation pipeline with comparable precision to the manual labels at the individual-level. The method first extracts individualized connectivity templates of areas 44 and 45 by assigning to each surface vertex within the ventrolateral frontal cortex the partial correlation value of its functional connectivity to group-level templates of areas 44 and 45, accounting for other template connectivity patterns. To account for cross-subject variability in connectivity, the partial correlation procedure is then repeated using individual-level network templates, including individual-level connectivity from areas 44 and 45. Each node is finally labeled as area 44, 45, or neither, using a winner-take-all approach. The method also incorporates prior knowledge of anatomical location by weighting the results using spatial probability maps. The resulting area labels show a high degree of spatial overlap with the gold-standard manual labels, and group-average area maps are consistent with cytoarchitectonic probability maps of areas 44 and 45. To facilitate reproducibility and to demonstrate that the method can be applied to resting-state fMRI datasets with varying acquisition and preprocessing parameters, the labeling procedure is applied to two open-source datasets from the Human Connectome Project and the Nathan Kline Institute Rockland Sample. While the current study focuses on Broca's region, the method is adaptable to parcellate other cortical regions with distinct connectivity profiles.

  16. Bidirectional iterative parcellation of diffusion weighted imaging data: separating cortical regions connected by the arcuate fasciculus and extreme capsule.

    PubMed

    Patterson, Dianne K; Van Petten, Cyma; Beeson, Pélagie M; Rapcsak, Steven Z; Plante, Elena

    2014-11-15

    This paper introduces a Bidirectional Iterative Parcellation (BIP) procedure designed to identify the location and size of connected cortical regions (parcellations) at both ends of a white matter tract in diffusion weighted images. The procedure applies the FSL option "probabilistic tracking with classification targets" in a bidirectional and iterative manner. To assess the utility of BIP, we applied the procedure to the problem of parcellating a limited set of well-established gray matter seed regions associated with the dorsal (arcuate fasciculus/superior longitudinal fasciculus) and ventral (extreme capsule fiber system) white matter tracts in the language networks of 97 participants. These left hemisphere seed regions and the two white matter tracts, along with their right hemisphere homologues, provided an excellent test case for BIP because the resulting parcellations overlap and their connectivity via the arcuate fasciculi and extreme capsule fiber systems are well studied. The procedure yielded both confirmatory and novel findings. Specifically, BIP confirmed that each tract connects within the seed regions in unique, but expected ways. Novel findings included increasingly left-lateralized parcellations associated with the arcuate fasciculus/superior longitudinal fasciculus as a function of age and education. These results demonstrate that BIP is an easily implemented technique that successfully confirmed cortical connectivity patterns predicted in the literature, and has the potential to provide new insights regarding the architecture of the brain.

  17. Groupwise whole-brain parcellation from resting-state fMRI data for network node identification

    PubMed Central

    Shen, X.; Tokoglu, F.; Papademetris, X.; Constable, R. T.

    2013-01-01

    In this paper, we present a groupwise graph-theory-based parcellation approach to define nodes for network analysis. The application of network-theory-based analysis to extend the utility of functional MRI has recently received increased attention. Such analyses require first and foremost a reasonable definition of a set of nodes as input to the network analysis. To date many applications have used existing atlases based on cytoarchitecture, task-based fMRI activations, or anatomic delineations. A potential pitfall in using such atlases is that the mean timecourse of a node may not represent any of the constituent timecourses if different functional areas are included within a single node. The proposed approach involves a groupwise optimization that ensures functional homogeneity within each subunit and that these definitions are consistent at the group level. Parcellation reproducibility of each subunit is computed across multiple groups of healthy volunteers and is demonstrated to be high. Issues related to the selection of appropriate number of nodes in the brain are considered. Within typical parameters of fMRI resolution, parcellation results are shown for a total of 100, 200, and 300 subunits. Such parcellations may ultimately serve as a functional atlas for fMRI and as such three atlases at the 100-, 200- and 300-parcellation levels derived from 79 healthy normal volunteers are made freely available online along with tools to interface this atlas with SPM, BioImageSuite and other analysis packages. PMID:23747961

  18. Joint Spectral Decomposition for the Parcellation of the Human Cerebral Cortex Using Resting-State fMRI.

    PubMed

    Arslan, Salim; Parisot, Sarah; Rueckert, Daniel

    2015-01-01

    Identification of functional connections within the human brain has gained a lot of attention due to its potential to reveal neural mechanisms. In a whole-brain connectivity analysis, a critical stage is the computation of a set of network nodes that can effectively represent cortical regions. To address this problem, we present a robust cerebral cortex parcellation method based on spectral graph theory and resting-state fMRI correlations that generates reliable parcellations at the single-subject level and across multiple subjects. Our method models the cortical surface in each hemisphere as a mesh graph represented in the spectral domain with its eigenvectors. We connect cortices of different subjects with each other based on the similarity of their connectivity profiles and construct a multi-layer graph, which effectively captures the fundamental properties of the whole group as well as preserves individual subject characteristics. Spectral decomposition of this joint graph is used to cluster each cortical vertex into a subregion in order to obtain whole-brain parcellations. Using rs-fMRI data collected from 40 healthy subjects, we show that our proposed algorithm computes highly reproducible parcellations across different groups of subjects and at varying levels of detail with an average Dice score of 0.78, achieving up to 9% better reproducibility compared to existing approaches. We also report that our group-wise parcellations are functionally more consistent, thus, can be reliably used to represent the population in network analyses.

  19. Groupwise whole-brain parcellation from resting-state fMRI data for network node identification.

    PubMed

    Shen, X; Tokoglu, F; Papademetris, X; Constable, R T

    2013-11-15

    In this paper, we present a groupwise graph-theory-based parcellation approach to define nodes for network analysis. The application of network-theory-based analysis to extend the utility of functional MRI has recently received increased attention. Such analyses require first and foremost a reasonable definition of a set of nodes as input to the network analysis. To date many applications have used existing atlases based on cytoarchitecture, task-based fMRI activations, or anatomic delineations. A potential pitfall in using such atlases is that the mean timecourse of a node may not represent any of the constituent timecourses if different functional areas are included within a single node. The proposed approach involves a groupwise optimization that ensures functional homogeneity within each subunit and that these definitions are consistent at the group level. Parcellation reproducibility of each subunit is computed across multiple groups of healthy volunteers and is demonstrated to be high. Issues related to the selection of appropriate number of nodes in the brain are considered. Within typical parameters of fMRI resolution, parcellation results are shown for a total of 100, 200, and 300 subunits. Such parcellations may ultimately serve as a functional atlas for fMRI and as such three atlases at the 100-, 200- and 300-parcellation levels derived from 79 healthy normal volunteers are made freely available online along with tools to interface this atlas with SPM, BioImage Suite and other analysis packages.

  20. Four-body trajectory optimization

    NASA Technical Reports Server (NTRS)

    Pu, C. L.; Edelbaum, T. N.

    1973-01-01

    A collection of typical three-body trajectories from the L1 libration point on the sun-earth line to the earth is presented. These trajectories in the sun-earth system are grouped into four distinct families which differ in transfer time and delta V requirements. Curves showing the variations of delta V with respect to transfer time, and typical two and three-impulse primer vector histories, are included. The development of a four-body trajectory optimization program to compute fuel optimal trajectories between the earth and a point in the sun-earth-moon system are also discussed. Methods for generating fuel optimal two-impulse trajectories which originate at the earth or a point in space, and fuel optimal three-impulse trajectories between two points in space, are presented. A brief qualitative comparison of these methods is given. An example of a four-body two-impulse transfer from the Li libration point to the earth is included.

  1. Transport of Australian Continental Dust to Australia's Great Barrier Reef Region: First Results From Sampling, Remote Sensing, Synoptic and Trajectory Analyses

    NASA Astrophysics Data System (ADS)

    Tapper, N.; O'Loingsigh, T.; de Deckker, P.; Cohen, D.

    2009-04-01

    As part of a large multi-disciplinary project funded by the Australian Research Council and in collaboration with the Australian Nuclear Science and Technology Organisation, we established in mid-2008 three PM 2.5 samplers in eastern Australia to determine possible transport of continental dust from the major dust source region of the Lake Eyre Basin (LEB). These samplers were located at Fowlers Gap, New South Wales [NSW] (31.09S, 141.70E), Mount Stromlo, NSW (35.30S, 149.00E) and Heron Island, Queensland (23.44S, 151.83E). The latter location is of particular significance because of its proximity to the World Heritage Great Barrier Reef (GBR) and to the tropical rainforest of coastal North Queensland. In previous studies, dust and associated organic material of African origin has been associated with rainforest fertilisation in Amazonia and coral bleaching in the Carribean. In this presentation three case studies of continental dust transport to Heron Island that occurred in the first four months of sampling are examined. In each case transport of soil material from the LEB region and/or western NSW is confirmed by the nature of material sampled, by remote sensing of the dust, by forward and backward air parcel trajectory analysis and by synoptic analysis. In each case the dust arrived over Heron Island 3-7 days after passing over the southern samplers, generally having followed an anti-clockwise curved path to approach Heron Island from the southeast. The potential significance of this finding for the GBR is briefly discussed.

  2. Hermes emergency reentry trajectories consequences on the Ariane 5 trajectories

    NASA Astrophysics Data System (ADS)

    Delattre, Ph.; Wagner, A.

    1990-06-01

    Hermes emergency reentry trajectories occur in case of any failure during that part of the launch phase from jettisoning the burn-out solid propellant boosters till the ignition of the MPH. In that case the Crew Escape Module cannot be used because of high Mach numbers and very severe constraints that would result of its low lift coefficient. The maximum constraints on the Hermes space plane are obtained in the atmospheric reentry phase of the emergency trajectories. Their important level is due to the deep flight path angle attained during the ballistic arc of the trajectory. Their values are depending on the instant of launch abort. These maximum constraints are very depending on the launch trajectory. The maximum Hermes constraints were represented in the altitude-velocity plane as a maximum altitude boundary for the Ariane 5 launch trajectory. Unfortunately a performance loss is the result of the requirement for a reduction of the culmination altitude. This has lead to a launch trajectory optimization that will be detailed in this paper. As an out-come of this study two important decisions have been made by CNES: choice of a L6 for the Hermes propulsion module; and the choice of the boundary that constraints the launch trajectory. Important efforts were made on Hermes in order to reduce the maximum constraints, in the field of aerodynamics (moment coefficient reduction, increase of the maximum angle of attack), center of gravity location (in order to reduce control surfaces hinge-moments and temperatures) and elevon-body-flap differential deflection.

  3. A performance measure for evaluating aircraft landing trajectories

    NASA Technical Reports Server (NTRS)

    Witt, R. M.; Cook, G.

    1978-01-01

    A general performance index is developed for evaluating aircraft landing trajectories. The primary term in the index is the effect of noise on people residing near the air terminal. Other terms included are passenger comfort, fuel consumed, and the time spent in the near-terminal area. Models are developed for aircraft engine noise, passenger comfort, the population distribution about a specific airport, and the aircraft flight behavior. While this performance index may be used in computing optimal trajectories, it is also useful for comparing nonoptimal trajectories which, for one reason or another, may be worthy of consideration. Some examples of such comparisons are included through simulations of landing. The aircraft considered is a Boeing 737.

  4. Trajectories in Operating a Handheld Tool

    ERIC Educational Resources Information Center

    Heuer, Herbert; Sulzenbruck, Sandra

    2009-01-01

    The authors studied the trajectories of the hand and of the tip of a handheld sliding first-order lever in aiming movements. With this kind of tool, straight trajectories of the hand are generally associated with curved trajectories of the tip of the lever and vice versa. Trajectories of the tip of the lever exhibited smaller deviations from…

  5. TAOS. Trajectory Analysis and Optimization System

    SciTech Connect

    Salguero, D.E.

    1995-12-09

    TAOS is a general-purpose software tool capable of analyzing nearly any type of three degree-of-freedom point-mass, high-speed trajectory. Input files contain aerodynamic coefficients, propulsion data, and a trajectory description. The trajectory description divides the trajectory into segments, and within each segment, guidance rules provided by the user describe how the trajectory is computed. Output files contain tabulated trajectory information such as position, velocity, and acceleration. Parametric optimization provides a powerful method for satisfying mission-planning constraints, and trajectories involving more than one vehicle can be computed within a single problem.

  6. Bystanders, parcelling, and an absence of trust in the grooming interactions of wild male chimpanzees

    PubMed Central

    Kaburu, Stefano S. K.; Newton-Fisher, Nicholas E.

    2016-01-01

    The evolution of cooperation remains a central issue in socio-biology with the fundamental problem of how individuals minimize the risks of being short-changed (‘cheated’) should their behavioural investment in another not be returned. Economic decisions that individuals make during interactions may depend upon the presence of potential partners nearby, which offers co operators a temptation to defect from the current partner. The parcelling model posits that donors subdivide services into parcels to force cooperation, and that this is contingent on opportunities for defection; that is, the presence of bystanders. Here we test this model and the effect of bystander presence using grooming interactions of wild chimpanzees. We found that with more bystanders, initiators gave less grooming at the beginning of the bout and were more likely to abandon a grooming bout, while bouts were less likely to be reciprocated. We also found that the groomer’s initial investment was not higher among frequent groomers or stronger reciprocators, suggesting that contrary to current assumptions, grooming decisions are not based on trust, or bonds, within dyads. Our work highlights the importance of considering immediate social context and the influence of bystanders for understanding the evolution of the behavioural strategies that produce cooperation. PMID:26856371

  7. Functional connectivity-based parcellation of amygdala using self-organized mapping: a data driven approach.

    PubMed

    Mishra, Arabinda; Rogers, Baxter P; Chen, Li Min; Gore, John C

    2014-04-01

    The overall goal of this work is to demonstrate how resting state functional magnetic resonance imaging (fMRI) signals may be used to objectively parcellate functionally heterogeneous subregions of the human amygdala into structures characterized by similar patterns of functional connectivity. We hypothesize that similarity of functional connectivity of subregions with other parts of the brain can be a potential basis to segment and cluster voxels using data driven approaches. In this work, self-organizing map (SOM) was implemented to cluster the connectivity maps associated with each voxel of the human amygdala, thereby defining distinct subregions. The functional separation was optimized by evaluating the overall differences in functional connectivity between the subregions at group level. Analysis of 25 resting state fMRI data sets suggests that SOM can successfully identify functionally independent nuclei based on differences in their inter subregional functional connectivity, evaluated statistically at various confidence levels. Although amygdala contains several nuclei whose distinct roles are implicated in various functions, our objective approach discerns at least two functionally distinct volumes comparable to previous parcellation results obtained using probabilistic tractography and cytoarchitectonic analysis. Association of these nuclei with various known functions and a quantitative evaluation of their differences in overall functional connectivity with lateral orbital frontal cortex and temporal pole confirms the functional diversity of amygdala. The data driven approach adopted here may be used as a powerful indicator of structure-function relationships in the amygdala and other functionally heterogeneous structures as well.

  8. Evaluating the Characteristics of Social Vulnerability to Wildfire: Demographics, Perceptions, and Parcel Characteristics

    NASA Astrophysics Data System (ADS)

    Paveglio, Travis B.; Prato, Tony; Edgeley, Catrin; Nalle, Darek

    2016-09-01

    A large body of research focuses on identifying patterns of human populations most at risk from hazards and the factors that help explain performance of mitigations that can help reduce that risk. One common concept in such studies is social vulnerability—human populations' potential exposure to, sensitivity from and ability to reduce negative impacts from a hazard. While there is growing interest in social vulnerability for wildfire, few studies have critically evaluated the characteristics that scholars often indicate influence social vulnerability to that hazard. This research utilizes surveys, wildfire simulations, and GIS data to test the relationships between select demographic, perceptual and parcel characteristics of property owners against empirically simulated metrics for wildfire exposure or wildfire-related damages and their performance of mitigation actions. Our results from Flathead County, MT, USA, suggest that parcel characteristics such as property value, building value, and the year structures were built explaining a significant amount of the variance in elements of social vulnerability. Demographic characteristics commonly used in social vulnerability analysis did not have significant relationships with measures of wildfire exposure or vulnerability. Part-time or full-time residency, age, perceived property risk, and year of development were among the few significant determinants of residents' performance of fuel reduction mitigations, although the significance of these factors varied across the levels of fuel reduction performed by homeowners. We use these and other results to argue for a renewed focus on the finer-scale characteristics that expose some populations to wildfire risk more than others.

  9. Connectivity-based parcellation reveals distinct cortico-striatal connectivity fingerprints in Autism Spectrum Disorder.

    PubMed

    Balsters, Joshua H; Mantini, Dante; Wenderoth, Nicole

    2017-02-08

    Autism Spectrum Disorder (ASD) has been associated with abnormal synaptic development causing a breakdown in functional connectivity. However, when measured at the macro scale using resting state fMRI, these alterations are subtle and often difficult to detect due to the large heterogeneity of the pathology. Recently, we outlined a novel approach for generating robust biomarkers of resting state functional magnetic resonance imaging (RS-fMRI) using connectivity based parcellation of gross morphological structures to improve single-subject reproducibility and generate more robust connectivity fingerprints. Here we apply this novel approach to investigating the organization and connectivity strength of the cortico-striatal system in a large sample of ASD individuals and typically developed (TD) controls (N=130 per group). Our results showed differences in the parcellation of the striatum in ASD. Specifically, the putamen was found to be one single structure in ASD, whereas this was split into anterior and posterior segments in an age, IQ, and head movement matched TD group. An analysis of the connectivity fingerprints revealed that the group differences in clustering were driven by differential connectivity between striatum and the supplementary motor area, posterior cingulate cortex, and posterior insula. Our approach for analysing RS-fMRI in clinical populations has provided clear evidence that cortico-striatal circuits are organized differently in ASD. Based on previous task-based segmentations of the striatum, we believe that the anterior putamen cluster present in TD, but not in ASD, likely contributes to social and language processes.

  10. Stratospheric balloons trajectories predictions and optimizations

    NASA Astrophysics Data System (ADS)

    Musso, I.; Cardillo, A.; Memmo, A.

    Trajectory predictions are becoming an important part of the stratospheric balloons activities due to the increased safety and scientific requirements Often high-populated areas must be avoided while the balloon could be asked to reach regions interesting for scientific measurements The balloon trajectory s reconstruction is essentially a time propagation of local wind vectors along the expected altitudes As consequence the predictor is composed of two interconnected subsystems one for the definition of vertical position and one for the wind predictions and horizontal propagation at every time step Forecast data permits up to 6 days of wind vector predictions Below 10mb altitude mesoscale models reduce the wind prediction uncertainty Directly measured information comes from radiosoundings few hours before flight or during it GPS onboard the balloon telemetry is a second direct wind data source The software has to mesh these different flows of information giving to the measured values a weight inversely proportional to the time and space distance from wind measurements In this way sounding data if properly used are able to reduce the path s dispersion A thermodynamic model reconstructs the balloon vertical positions Heat exchanges between internal gas and external environment are very sensitive to air temperature infrared radiance and albedo Again forecast data have to be properly meshed with radiosoundings and satellite images to obtain the best values of these border conditions They will apply the thermodynamic balloon model We

  11. Experimental Evaluation of an Integrated Datalink and Automation-Based Strategic Trajectory Concept

    NASA Technical Reports Server (NTRS)

    Mueller, Eric

    2007-01-01

    This paper presents research on the interoperability of trajectory-based automation concepts and technologies with modern Flight Management Systems and datalink communication available on many of today s commercial aircraft. A tight integration of trajectory-based ground automation systems with the aircraft Flight Management System through datalink will enable mid-term and far-term benefits from trajectory-based automation methods. A two-way datalink connection between the trajectory-based automation resident in the Center/TRACON Automation System and the Future Air Navigation System-1 integrated FMS/datalink in NASA Ames B747-400 Level D simulator has been established and extensive simulation of the use of datalink messages to generate strategic trajectories completed. A strategic trajectory is defined as an aircraft deviation needed to solve a conflict or honor a route request and then merge the aircraft back to its nominal preferred trajectory using a single continuous trajectory clearance. Engineers on the ground side of the datalink generated lateral and vertical trajectory clearances and transmitted them to the Flight Management System of the 747; the airborne automation then flew the new trajectory without human intervention, requiring the flight crew only to review and to accept the trajectory. This simulation established the protocols needed for a significant majority of the trajectory change types required to solve a traffic conflict or deviate around weather. This demonstration provides a basis for understanding the requirements for integration of trajectory-based automation with current Flight Management Systems and datalink to support future National Airspace System operations.

  12. CFD Analysis of Swing of Cricket Ball and Trajectory Prediction

    NASA Astrophysics Data System (ADS)

    G, Jithin; Tom, Josin; Ruishikesh, Kamat; Jose, Jyothish; Kumar, Sanjay

    2013-11-01

    This work aims to understand the aerodynamics associated with the flight and swing of a cricket ball and predict its flight trajectory over the course of the game: at start (smooth ball) and as the game progresses (rough ball). Asymmetric airflow over the ball due to seam orientation and surface roughness can cause flight deviation (swing). The values of Drag, Lift and Side forces which are crucial for determining the trajectory of the ball were found with the help of FLUENT using the standard K- ɛ model. Analysis was done to study how the ball velocity, spin imparted to be ball and the tilt of the seam affects the movement of the ball through air. The governing force balance equations in 3 dimensions in combination a MATLAB code which used Heun's method was used for obtaining the trajectory of the ball. The conditions for the conventional swing and reverse swing to occur were deduced from the analysis and found to be in alignment with the real life situation. Critical seam angle for maximum swing and transition speed for normal to reverse swing were found out. The obtained trajectories were compared to real life hawk eye trajectories for validation. The analysis results were in good agreement with the real life situation.

  13. Complexity Management Using Metrics for Trajectory Flexibility Preservation and Constraint Minimization

    NASA Technical Reports Server (NTRS)

    Idris, Husni; Shen, Ni; Wing, David J.

    2011-01-01

    The growing demand for air travel is increasing the need for mitigating air traffic congestion and complexity problems, which are already at high levels. At the same time new surveillance, navigation, and communication technologies are enabling major transformations in the air traffic management system, including net-based information sharing and collaboration, performance-based access to airspace resources, and trajectory-based rather than clearance-based operations. The new system will feature different schemes for allocating tasks and responsibilities between the ground and airborne agents and between the human and automation, with potential capacity and cost benefits. Therefore, complexity management requires new metrics and methods that can support these new schemes. This paper presents metrics and methods for preserving trajectory flexibility that have been proposed to support a trajectory-based approach for complexity management by airborne or ground-based systems. It presents extensions to these metrics as well as to the initial research conducted to investigate the hypothesis that using these metrics to guide user and service provider actions will naturally mitigate traffic complexity. The analysis showed promising results in that: (1) Trajectory flexibility preservation mitigated traffic complexity as indicated by inducing self-organization in the traffic patterns and lowering traffic complexity indicators such as dynamic density and traffic entropy. (2)Trajectory flexibility preservation reduced the potential for secondary conflicts in separation assurance. (3) Trajectory flexibility metrics showed potential application to support user and service provider negotiations for minimizing the constraints imposed on trajectories without jeopardizing their objectives.

  14. 27 CFR 44.225 - Delivery of tobacco products, or cigarette papers or tubes for export other than by parcel post.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... products, or cigarette papers or tubes for export other than by parcel post. 44.225 Section 44.225 Alcohol... (CONTINUED) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX... tubes for export other than by parcel post. The claimant, upon release of the tobacco products,...

  15. 27 CFR 44.225 - Delivery of tobacco products, or cigarette papers or tubes for export other than by parcel post.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... products, or cigarette papers or tubes for export other than by parcel post. 44.225 Section 44.225 Alcohol... (CONTINUED) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX... tubes for export other than by parcel post. The claimant, upon release of the tobacco products,...

  16. 27 CFR 44.225 - Delivery of tobacco products, or cigarette papers or tubes for export other than by parcel post.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... products, or cigarette papers or tubes for export other than by parcel post. 44.225 Section 44.225 Alcohol... (CONTINUED) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX... tubes for export other than by parcel post. The claimant, upon release of the tobacco products,...

  17. 27 CFR 44.225 - Delivery of tobacco products, or cigarette papers or tubes for export other than by parcel post.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... products, or cigarette papers or tubes for export other than by parcel post. 44.225 Section 44.225 Alcohol... (CONTINUED) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX... tubes for export other than by parcel post. The claimant, upon release of the tobacco products,...

  18. 27 CFR 44.225 - Delivery of tobacco products, or cigarette papers or tubes for export other than by parcel post.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... products, or cigarette papers or tubes for export other than by parcel post. 44.225 Section 44.225 Alcohol... (CONTINUED) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX... tubes for export other than by parcel post. The claimant, upon release of the tobacco products,...

  19. Ion drive performance and trajectories

    NASA Technical Reports Server (NTRS)

    Yen, C. L.

    1978-01-01

    The use of Solar Electric Propulsion (SEP) for the Solar Probe Mission is addressed. The dependence of the payload mass on the site of the SEP and the flight time are described on the basis of preliminary data. The range of hardware expected to be available in the 1980's is summarized. There are several classes of optimal low-thrust trajectories for the Solar Probe Mission. These are trajectory types A, B, C corresponding to one, two, or three orbital revolutions, respectively. Plots of transfer trajectories corresponding to type-A, type-A with a Venus Swingby, type-B, and type-C with ab Icarus Rendezvous are shown. A summary of the SEP performance is given.

  20. Trajectory generation of space telerobots

    NASA Technical Reports Server (NTRS)

    Lumia, R.; Wavering, A. J.

    1989-01-01

    The purpose is to review a variety of trajectory generation techniques which may be applied to space telerobots and to identify problems which need to be addressed in future telerobot motion control systems. As a starting point for the development of motion generation systems for space telerobots, the operation and limitations of traditional path-oriented trajectory generation approaches are discussed. This discussion leads to a description of more advanced techniques which have been demonstrated in research laboratories, and their potential applicability to space telerobots. Examples of this work include systems that incorporate sensory-interactive motion capability and optimal motion planning. Additional considerations which need to be addressed for motion control of a space telerobot are described, such as redundancy resolution and the description and generation of constrained and multi-armed cooperative motions. A task decomposition module for a hierarchical telerobot control system which will serve as a testbed for trajectory generation approaches which address these issues is also discussed briefly.

  1. Ballute Aerocapture Trajectories at Neptune

    NASA Technical Reports Server (NTRS)

    Lyons, Daniel T.; Johnson, Wyatt

    2004-01-01

    Using an inflatable ballute system for aerocapture at planets and moons with atmospheres has the potential to provide significant performance benefits compared not only to traditional all propulsive capture, but also to aeroshell based aerocapture technologies. This paper discusses the characteristics of entry trajectories for ballute aerocapture at Neptune. These trajectories are the first steps in a larger systems analysis effort that is underway to characterize and optimize the performance of a ballute aerocapture system for future missions not only at Neptune, but also the other bodies with atmospheres.

  2. Predicting Adult Offenders' Criminal Trajectories from Their Juvenile Criminal Trajectories.

    ERIC Educational Resources Information Center

    Day, David M.; Bevc, Irene; Rosenthal, Jeffrey S.; Duchesne, Thierry; Rossman, Lianne; Theodor, Frances

    This study examined the relationship between adolescent (10-17 years) criminal offending and adult (18-33 years) offending. The sample comprised 378 Canadian male offenders whose criminal trajectory was tracked for an average of 12.1 years, from adolescence into adulthood. Their man age at the time of the most recent follow-up was 27.5 years. The…

  3. Comparison of ER-2 Aircraft and POAM-III, MLS, and SAGE-II Satellite Measurements During SOLVE Using Traditional Correlative Analysis and Trajectory Hunting Technique

    NASA Technical Reports Server (NTRS)

    Danilin, M. Y.; Ko, Malcolm K. W.; Bevilacqua, R. M.; Lyjak, L. V.; Froidevaux, L.; Santee, M. L.; Zawodny, J. M.; Hoppel, K. W.; Richard, E. C.; Spackman, J. R.; Jackman, Charles H. (Technical Monitor)

    2001-01-01

    We compared the version 5 Microwave Limb Sounder (MLS) aboard the Upper Atmosphere Research Satellite (UARS), version 3 Polar Ozone and Aerosol Measurement-III (POAM-111) aboard the French satellite SPOT-IV, version 6.0 Stratospheric Aerosol and Gas Experiment 11 (SAGE-II) aboard the Earth Radiation Budget Satellite, and NASA ER-2 aircraft measurements made in the northern hemisphere in January-February 2000 during the SAGE III Ozone Loss and Validation Experiment (SOLVE). This study addresses one of the key scientific objectives of the SOLVE campaign, namely, to validate multi-platform satellite measurements made in the polar stratosphere during winter. This intercomparison was performed using a traditional correlative analysis (TCA) and a trajectory hunting technique (THT). Launching backward and forward trajectories from the points of measurement, the THT identifies air parcels sampled at least twice within a prescribed match criterion during the course of 5 days. We found that the ozone measurements made by these four instruments agree most of the time within 110% in the stratosphere up to 1400 K (approximately 35 km). The water vapor measurements from POAM-III and the ER-2 Harvard Lyman-alpha hygrometer and JPL laser hygrometer agree to within 10.5 ppmv (or about +/-10%) in the lower stratosphere above 380 K. The MLS and ER-2 ClO measurements agree within their error bars for the TCA. The MLS and ER-2 nitric acid measurements near 17-20 km altitude agree within their uncertainties most of the time with a hint of a positive offset by MLS according to the TCA. We also applied the AER box model constrained by the ER-2 measurements for analysis of the ClO and HN03 measurements using the THT. We found that: (1) the model values of ClO are smaller by about 0.3-0.4 (0.2) ppbv below (above) 400 K than those by MLS and (2) the HN03 comparison shows a positive offset of MLS values by approximately 1 and 1-2 ppbv below 400 K and near 450 K, respectively. It is hard to

  4. Chemical trends in background air quality and the ionic composition of precipitation for the period 1980-2004 from samples collected at Valentia Observatory, Co. Kerry, Ireland.

    PubMed

    Bashir, Wasim; McGovern, Frank; O'Brien, Phillip; Ryan, Margaret; Burke, Liam; Paull, Brett

    2008-06-01

    A major Irish study, based upon more than 8000 samples collected over the measurement period of 22 years, for sulfur dioxide (SO2-S), sulfate (SO4-S) and nitrogen dioxide (NO2-N) concentrations (microg m(-3)) within air, and the ionic composition of precipitation samples based on sodium (Na+), potassium (K+), magnesium (Mg2+), calcium (Ca2+), chloride (Cl-), sulfate (SO4-S), non-sea salt sulfate (nssSO4-S), ammonium (NH4-N), and nitrate (NO3-N) weighted mean concentrations (mg l(-1)), has been completed. For the air samples, the sulfur dioxide and sulfate concentrations decreased over the sampling period (1980-2004) by 75% and 45%, respectively, whereas no significant trend was observed for nitrogen dioxide. The highest concentrations for sulfur dioxide, sulfate and nitrogen dioxide were associated with wind originating from the easterly and northeasterly directions i.e. those influenced by Irish and European sources. The lowest concentrations were associated with the westerly directions i.e. for air masses originating in the North Atlantic region. This was further verified with the use of backward (back) trajectory analysis, which allowed tracing the movement of air parcels using the European Centre for Medium range Weather Forecasting (ECMWF) ERA-40 re-analysis data. High non-sea salt sulfate levels were being associated with air masses originating from Europe (easterlies) with lower levels from the Atlantic (westerlies). With the precipitation data, analysis of the non-sea salt sulfate concentrations showed a decrease by 47% since the measurements commenced.

  5. Distributed Trajectory Flexibility Preservation for Traffic Complexity Mitigation

    NASA Technical Reports Server (NTRS)

    Idris, Husni; Wing, David; Delahaye, Daniel

    2009-01-01

    The growing demand for air travel is increasing the need for mitigation of air traffic congestion and complexity problems, which are already at high levels. At the same time new information and automation technologies are enabling the distribution of tasks and decisions from the service providers to the users of the air traffic system, with potential capacity and cost benefits. This distribution of tasks and decisions raises the concern that independent user actions will decrease the predictability and increase the complexity of the traffic system, hence inhibiting and possibly reversing any potential benefits. In answer to this concern, the authors propose the introduction of decision-making metrics for preserving user trajectory flexibility. The hypothesis is that such metrics will make user actions naturally mitigate traffic complexity. In this paper, the impact of using these metrics on traffic complexity is investigated. The scenarios analyzed include aircraft in en route airspace with each aircraft meeting a required time of arrival in a one-hour time horizon while mitigating the risk of loss of separation with the other aircraft, thus preserving its trajectory flexibility. The experiments showed promising results in that the individual trajectory flexibility preservation induced self-separation and self-organization effects in the overall traffic situation. The effects were quantified using traffic complexity metrics based on Lyapunov exponents and traffic proximity.

  6. Analysis of Trajectory Flexibility Preservation Impact on Traffic Complexity

    NASA Technical Reports Server (NTRS)

    Idris, Husni; El-Wakil, Tarek; Wing, David J.

    2009-01-01

    The growing demand for air travel is increasing the need for mitigation of air traffic congestion and complexity problems, which are already at high levels. At the same time new information and automation technologies are enabling the distribution of tasks and decisions from the service providers to the users of the air traffic system, with potential capacity and cost benefits. This distribution of tasks and decisions raises the concern that independent user actions will decrease the predictability and increase the complexity of the traffic system, hence inhibiting and possibly reversing any potential benefits. In answer to this concern, the authors proposed the introduction of decision-making metrics for preserving user trajectory flexibility. The hypothesis is that such metrics will make user actions naturally mitigate traffic complexity. In this paper, the impact of using these metrics on traffic complexity is investigated. The scenarios analyzed include aircraft in en route airspace with each aircraft meeting a required time of arrival in a one-hour time horizon while mitigating the risk of loss of separation with the other aircraft, thus preserving its trajectory flexibility. The experiments showed promising results in that the individual trajectory flexibility preservation induced self-separation and self-organization effects in the overall traffic situation. The effects were quantified using traffic complexity metrics, namely dynamic density indicators, which indicated that using the flexibility metrics reduced aircraft density and the potential of loss of separation.

  7. Distance Education: Educational Trajectory Control

    ERIC Educational Resources Information Center

    Isaev, Andrey; Kravets, Alla; Isaeva, Ludmila; Fomenkov, Sergey

    2013-01-01

    Distance education has become a rather popular form of education recently. The advantages of this form are obvious and well-known. They include asynchronous learning, individualized learning trajectories and convenient case technologies. However, the distance form of education is not able to form the trainee's hands-on experience, especially…

  8. Visiting Vehicle Ground Trajectory Tool

    NASA Technical Reports Server (NTRS)

    Hamm, Dustin

    2013-01-01

    The International Space Station (ISS) Visiting Vehicle Group needed a targeting tool for vehicles that rendezvous with the ISS. The Visiting Vehicle Ground Trajectory targeting tool provides the ability to perform both realtime and planning operations for the Visiting Vehicle Group. This tool provides a highly reconfigurable base, which allows the Visiting Vehicle Group to perform their work. The application is composed of a telemetry processing function, a relative motion function, a targeting function, a vector view, and 2D/3D world map type graphics. The software tool provides the ability to plan a rendezvous trajectory for vehicles that visit the ISS. It models these relative trajectories using planned and realtime data from the vehicle. The tool monitors ongoing rendezvous trajectory relative motion, and ensures visiting vehicles stay within agreed corridors. The software provides the ability to update or re-plan a rendezvous to support contingency operations. Adding new parameters and incorporating them into the system was previously not available on-the-fly. If an unanticipated capability wasn't discovered until the vehicle was flying, there was no way to update things.

  9. Classical Trajectories and Quantum Spectra

    NASA Technical Reports Server (NTRS)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  10. Trajectory optimization using regularized variables

    NASA Technical Reports Server (NTRS)

    Lewallen, J. M.; Szebehely, V.; Tapley, B. D.

    1969-01-01

    Regularized equations for a particular optimal trajectory are compared with unregularized equations with respect to computational characteristics, using perturbation type numerical optimization. In the case of the three dimensional, low thrust, Earth-Jupiter rendezvous, the regularized equations yield a significant reduction in computer time.

  11. Canonical Transformations of Kepler Trajectories

    ERIC Educational Resources Information Center

    Mostowski, Jan

    2010-01-01

    In this paper, canonical transformations generated by constants of motion in the case of the Kepler problem are discussed. It is shown that canonical transformations generated by angular momentum are rotations of the trajectory. Particular attention is paid to canonical transformations generated by the Runge-Lenz vector. It is shown that these…

  12. Aircraft flight test trajectory control

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1988-01-01

    Two design techniques for linear flight test trajectory controllers (FTTCs) are described: Eigenstructure assignment and the minimum error excitation technique. The two techniques are used to design FTTCs for an F-15 aircraft model for eight different maneuvers at thirty different flight conditions. An evaluation of the FTTCs is presented.

  13. Experimental nonlocal and surreal Bohmian trajectories

    PubMed Central

    Mahler, Dylan H.; Rozema, Lee; Fisher, Kent; Vermeyden, Lydia; Resch, Kevin J.; Wiseman, Howard M.; Steinberg, Aephraim

    2016-01-01

    Weak measurement allows one to empirically determine a set of average trajectories for an ensemble of quantum particles. However, when two particles are entangled, the trajectories of the first particle can depend nonlocally on the position of the second particle. Moreover, the theory describing these trajectories, called Bohmian mechanics, predicts trajectories that were at first deemed “surreal” when the second particle is used to probe the position of the first particle. We entangle two photons and determine a set of Bohmian trajectories for one of them using weak measurements and postselection. We show that the trajectories seem surreal only if one ignores their manifest nonlocality. PMID:26989784

  14. Available Instruments for Analyzing Molecular Dynamics Trajectories

    PubMed Central

    Likhachev, I. V.; Balabaev, N. K.; Galzitskaya, O. V.

    2016-01-01

    Molecular dynamics trajectories are the result of molecular dynamics simulations. Trajectories are sequential snapshots of simulated molecular system which represents atomic coordinates at specific time periods. Based on the definition, in a text format trajectory files are characterized by their simplicity and uselessness. To obtain information from such files, special programs and information processing techniques are applied: from molecular dynamics animation to finding characteristics along the trajectory (versus time). In this review, we describe different programs for processing molecular dynamics trajectories. The performance of these programs, usefulness for analyses of molecular dynamics trajectories, strong and weak aspects are discussed. PMID:27053964

  15. Some Concepts for Target Trajectory Predictions

    DTIC Science & Technology

    1994-03-01

    Threat Acceleration 2-1 3 STATE-BASED PREDICTORS 3-1 CV Trajectory 3-1 CA Trajectory 3-1 CTR Trajectory 3-1 EDTR Trajectory 3-2 Helical Trajectory 3-6...8 CONCLUSIONS 8-1 REFERENCES 9-1 V I I NSWCDD/TR-92/445 I U ILLUSTRATIONS I Figure Pa•e 3-1 Typical EDTR trajectory and asymptote 3-5 6-1 True and...predictors. The new state-based predictors include Constant Turning Rate (CTR), Exponentially Decreasing Turning Rate ( EDTR ), and Helical. The CTR

  16. 43 CFR 2568.80 - Does the parcel have to be surveyed before I can receive title to it?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... I can receive title to it? 2568.80 Section 2568.80 Public Lands: Interior Regulations Relating to... § 2568.80 Does the parcel have to be surveyed before I can receive title to it? Yes. The land in your application must be surveyed before BLM can convey it to you. BLM will survey your allotment at no charge...

  17. 43 CFR 2568.80 - Does the parcel have to be surveyed before I can receive title to it?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... I can receive title to it? 2568.80 Section 2568.80 Public Lands: Interior Regulations Relating to... § 2568.80 Does the parcel have to be surveyed before I can receive title to it? Yes. The land in your application must be surveyed before BLM can convey it to you. BLM will survey your allotment at no charge...

  18. 77 FR 54607 - Proclaiming Certain Lands, Dafter Parcel, as an Addition to the Bay Mills Indian Reservation for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-05

    ... radius of 11,609.16 feet and is subtended by a chord that bears S 14[deg]12'52'' W a distance of 1270.70.... A proclamation was issued according with Section 7 of the Act of June 18, 1934 (48 Stat. 986; 25 U.S... membership. Bay Mills Indian Community Reservation Township of Dafter, Chippewa County, Michigan A parcel...

  19. A Supervoxel-Based Method for Groupwise Whole Brain Parcellation with Resting-State fMRI Data

    PubMed Central

    Wang, Jing; Wang, Haixian

    2016-01-01

    Node definition is a very important issue in human brain network analysis and functional connectivity studies. Typically, the atlases generated from meta-analysis, random criteria, and structural criteria are utilized as nodes in related applications. However, these atlases are not originally designed for such purposes and may not be suitable. In this study, we combined normalized cut (Ncut) and a supervoxel method called simple linear iterative clustering (SLIC) to parcellate whole brain resting-state fMRI data in order to generate appropriate brain atlases. Specifically, Ncut was employed to extract features from connectivity matrices, and then SLIC was applied on the extracted features to generate parcellations. To obtain group level parcellations, two approaches named mean SLIC and two-level SLIC were proposed. The cluster number varied in a wide range in order to generate parcellations with multiple granularities. The two SLIC approaches were compared with three state-of-the-art approaches under different evaluation metrics, which include spatial contiguity, functional homogeneity, and reproducibility. Both the group-to-group reproducibility and the group-to-subject reproducibility were evaluated in our study. The experimental results showed that the proposed approaches obtained relatively good overall clustering performances in different conditions that included different weighting functions, different sparsifying schemes, and several confounding factors. Therefore, the generated atlases are appropriate to be utilized as nodes for network analysis. The generated atlases and major source codes of this study have been made publicly available at http://www.nitrc.org/projects/slic/. PMID:28082885

  20. Three Approaches to Using Lengthy Ordinal Scales in Structural Equation Models: Parceling, Latent Scoring, and Shortening Scales

    ERIC Educational Resources Information Center

    Yang, Chongming; Nay, Sandra; Hoyle, Rick H.

    2010-01-01

    Lengthy scales or testlets pose certain challenges for structural equation modeling (SEM) if all the items are included as indicators of a latent construct. Three general approaches to modeling lengthy scales in SEM (parceling, latent scoring, and shortening) have been reviewed and evaluated. A hypothetical population model is simulated containing…

  1. The Impact of the Parcel-Level Land Architecture on Land Surface Temperature in the Phoenix Metropolitan Area

    NASA Astrophysics Data System (ADS)

    LI, X.; Ouyang, Y.; Turner, B. L., II; Harlan, S.; Brazel, A.

    2014-12-01

    The relationship between land surface temperature (LST) and characteristics of the urban land system has received increasing attention in urban heat island research, especially for desert cities. The relationship between the land composition and LST has been widely studied. Such researches generally employ medium or coarser spatial resolution remotely sensed data and primarily focuses on the effects of one land cover type on the LST. In this study, we explore the effects of land system architecture - composition and configuration of different land-cover classes - on LST in the central Arizona-Phoenix metropolitan area at a fine-scale resolution, focused on the composition and configuration of single family residential parcels. A 1 m resolution land-cover map is used to calculate landscape metrics at the parcel level, and 6.8 m resolution data from the MODIS/ASTER are employed to retrieve LST. We introduce the socio-economic factors at neighborhood level as explanatory variables to help control for potential neighborhood effects. Multiple linear regression models examine the effects of landscape configuration on LST at the parcel scale, controlling for the effects of landscape composition and neighborhood characteristics. Results show that the configuration of parcels affects LST, revealing significant variable relationships between that architecture and LST at nighttime and daytime, and the role of the neighborhood effects on the outcomes.

  2. 77 FR 54607 - Proclaiming Certain Lands, Sugar Parcel Lands, as an Addition to the Bay Mills Indian Reservation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-05

    ... [Federal Register Volume 77, Number 172 (Wednesday, September 5, 2012)] [Notices] [Pages 54607-54608] [FR Doc No: 2012-21822] DEPARTMENT OF THE INTERIOR Bureau of Indian Affairs Proclaiming Certain Lands, Sugar Parcel Lands, as an Addition to the Bay Mills Indian Reservation for the Bay Mills...

  3. 27 CFR 44.226 - Delivery of tobacco products, and cigarette papers and tubes for export by parcel post.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco...) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX Drawback of Tax § 44.226 Delivery of tobacco products, and cigarette papers and tubes...

  4. 27 CFR 44.226 - Delivery of tobacco products, and cigarette papers and tubes for export by parcel post.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco...) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX Drawback of Tax § 44.226 Delivery of tobacco products, and cigarette papers and tubes...

  5. 27 CFR 44.226 - Delivery of tobacco products, and cigarette papers and tubes for export by parcel post.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco...) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX Drawback of Tax § 44.226 Delivery of tobacco products, and cigarette papers and tubes...

  6. 27 CFR 44.226 - Delivery of tobacco products, and cigarette papers and tubes for export by parcel post.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco...) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX Drawback of Tax § 44.226 Delivery of tobacco products, and cigarette papers and tubes...

  7. 27 CFR 44.226 - Delivery of tobacco products, and cigarette papers and tubes for export by parcel post.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco...) TOBACCO EXPORTATION OF TOBACCO PRODUCTS AND CIGARETTE PAPERS AND TUBES, WITHOUT PAYMENT OF TAX, OR WITH DRAWBACK OF TAX Drawback of Tax § 44.226 Delivery of tobacco products, and cigarette papers and tubes...

  8. Investigating Historic Parcel Changes to Understand Land Use Trends: A Methodology and Application for the San Pedro River Watershed

    EPA Science Inventory

    Long-term land use and land cover change, and the associated impacts, pose critical challenges to sustaining healthy communities and ecosystems. In this study, a methodology was developed to use parcel data to evaluate land use trends in southeast Arizona’s San Pedro River Water...

  9. Adapting parcellation schemes to study fetal brain connectivity in serial imaging studies.

    PubMed

    Cheng, Xi; Wilm, Jakob; Seshamani, Sharmishtaa; Fogtmann, Mads; Kroenke, Christopher; Studholme, Colin

    2013-01-01

    A crucial step in studying brain connectivity is the definition of the Regions Of Interest (ROI's) which are considered as nodes of a network graph. These ROI's identified in structural imaging reflect consistent functional regions in the anatomies being compared. However in serial studies of the developing fetal brain such functional and associated structural markers are not consistently present over time. In this study we adapt two non-atlas based parcellation schemes to study the development of connectivity networks of a fetal monkey brain using Diffusion Weighted Imaging techniques. Results demonstrate that the fetal brain network exhibits small-world characteristics and a pattern of increased cluster coefficients and decreased global efficiency. These findings may provide a route to creating a new biomarker for healthy fetal brain development.

  10. Thalamus parcellation using multi-modal feature classification and thalamic nuclei priors

    PubMed Central

    Glaister, Jeffrey; Carass, Aaron; Stough, Joshua V.; Calabresi, Peter A.; Prince, Jerry L.

    2016-01-01

    Segmentation of the thalamus and thalamic nuclei is useful to quantify volumetric changes from neurodegenerative diseases. Most thalamus segmentation algorithms only use T1-weighted magnetic resonance images and current thalamic parcellation methods require manual interaction. Smaller nuclei, such as the lateral and medial geniculates, are challenging to locate due to their small size. We propose an automated segmentation algorithm using a set of features derived from diffusion tensor image (DTI) and thalamic nuclei location priors. After extracting features, a hierarchical random forest classifier is trained to locate the thalamus. A second random forest classifies thalamus voxels as belonging to one of six thalamic nuclei classes. The proposed algorithm was tested using a leave-one-out cross validation scheme and compared with state-of-the-art algorithms. The proposed algorithm has a higher Dice score compared to other methods for the whole thalamus and several nuclei. PMID:27582600

  11. Regional structural differences across functionally parcellated Brodmann areas of human primary somatosensory cortex.

    PubMed

    Sánchez-Panchuelo, Rosa-María; Besle, Julien; Mougin, Olivier; Gowland, Penny; Bowtell, Richard; Schluppeck, Denis; Francis, Susan

    2014-06-01

    Ultra-high-field (UHF) MRI is ideally suited for structural and functional imaging of the brain. High-resolution structural MRI can be used to map the anatomical boundaries between functional domains of the brain by identifying changes related to the pattern of myelination within cortical gray matter, opening up the possibility to study the relationship between functional domains and underlying structure in vivo. In a recent study, we demonstrated the correspondence between functional (based on retinotopic mapping) and structural (based on changes in T2(⁎)-weighted images linked to myelination) parcellations of the primary visual cortex (V1) in vivo at 7T (Sanchez-Panchuelo et al., 2012b). Here, we take advantage of the improved BOLD CNR and high spatial resolution achievable at 7T to study regional structural variations across the functionally defined areas within the primary somatosensory cortex (S1) in individual subjects. Using a traveling wave fMRI paradigm to map the internal somatotopic representation of the index, middle, and ring fingers in S1, we were able to identify multiple map reversals at the tip and base, corresponding to the boundaries between Brodmann areas 3a, 3b, 1 and 2. Based on high resolution structural MRI data acquired in the same subjects, we inspected these functionally-parcellated Brodmann areas for differences in cortical thickness and MR contrast measures (magnetization transfer ratio (MTR) and signal intensity in phase sensitive inversion recovery (PSIR) images) that are sensitive to myelination. Consistent area-related differences in cortical thickness and MTR/PSIR measurements were found across subjects. However these measures did not have sufficient sensitivity to allow definition of areal boundaries.

  12. Human orbital and anterior medial prefrontal cortex: Intrinsic connectivity parcellation and functional organization.

    PubMed

    Samara, Zoe; Evers, Elisabeth A T; Goulas, Alexandros; Uylings, Harry B M; Rajkowska, Grazyna; Ramaekers, Johannes G; Stiers, Peter

    2017-03-02

    The orbital and medial prefrontal cortex (OMPFC) has been implicated in decision-making, reward and emotion processing, and psychopathology, such as depression and obsessive-compulsive disorder. Human and monkey anatomical studies indicate the presence of various cortical subdivisions and suggest that these are organized in two extended networks, a medial and an orbital one. Attempts have been made to replicate these neuroanatomical findings in vivo using MRI techniques for imaging connectivity. These revealed several consistencies, but also many inconsistencies between reported results. Here, we use fMRI resting-state functional connectivity (FC) and data-driven modularity optimization to parcellate the OMPFC to investigate replicability of in vivo parcellation more systematically. By collecting two resting-state data sets per participant, we were able to quantify the reliability of the observed modules and their boundaries. Results show that there was significantly more than chance overlap in modules and their boundaries at the level of individual data sets. Moreover, some of these consistent boundaries significantly co-localized across participants. Hierarchical clustering showed that the whole-brain FC profiles of the OMPFC subregions separate them in two networks, a medial and orbital one, which overlap with the organization proposed by Barbas and Pandya (J Comp Neurol 286:353-375, 1989) and Ongür and Price (Cereb Cortex 10:206-219, 2000). We conclude that in vivo resting-state FC can delineate reliable and neuroanatomically plausible subdivisions that agree with established cytoarchitectonic trends and connectivity patterns, while other subdivisions do not show the same consistency across data sets and studies.

  13. Volumetric Parcellation Methodology of the Human Hypothalamus in Neuroimaging: Normative Data and Sex Differences

    PubMed Central

    Makris, Nikos; Swaab, Dick F.; van der Kouwe, Andre; Abbs, Brandon; Boriel, Denise; Handa, Robert; Tobet, Stuart; Goldstein, Jill M.

    2013-01-01

    There is increasing evidence regarding the importance of the hypothalamus for understanding sex differences in relation to neurological, psychiatric, endocrine and sleep disorders. Although different in histology, physiology, connections and function, multiple hypothalamic nuclei subserve non-voluntary functions and are nodal points for the purpose of maintaining homeostasis of the organism. Thus, given the critical importance of hypothalamic nuclei and their key multiple roles in regulating basic functions, it is important to develop the ability to conduct in vivo human studies of anatomic structure, volume, connectivity, and function of hypothalamic regions represented at the level of its nuclei. The goals of the present study were to develop a novel method of semi-automated volumetric parcellation for the human hypothalamus that could be used to investigate clinical conditions using MRI and to demonstrate its applicability. The proposed new method subdivides the hypothalamus into five parcels based on visible anatomic landmarks associated with specific nuclear groupings and was confirmed using two ex vivo hypothalami that were imaged in a 7 Tesla (7T) scanner and processed histologically. Imaging results were compared with histology from the same brain. Further, the method was applied to 44 healthy adults (26 men; 18 women, comparable on age, handedness, ethnicity, SES) to derive normative volumes and assess sex differences in hypothalamic regions using 1.5 Tesla MRI. Men compared to women had a significantly larger total hypothalamus, relative to cerebrum size, similar for both hemispheres, a difference that was primarily driven by the tuberal region, with the sex effect size being largest in the superior tuberal region and, to a lesser extent, inferior tuberal region. Given the critical role of hypothalamic nuclei in multiple chronic diseases and the importance of sex differences, we argue that the use of the novel methodology presented here will allow for

  14. Clean Air Slots Amid Atmospheric Pollution

    NASA Technical Reports Server (NTRS)

    Hobbs, Peter V.

    2002-01-01

    Layering in the Earth's atmosphere is most commonly seen where parts of the atmosphere resist the incursion of air parcels from above and below - for example, when there is an increase in temperature with height over a particular altitude range. Pollutants tend to accumulate underneath the resulting stable layers. which is why visibility often increases markedly above certain altitudes. Here we describe the occurrence of an opposite effect, in which stable layers generate a layer of remarkably clean air (we refer to these layers as clean-air 'slots') sandwiched between layers of polluted air. We have observed clean-air slots in various locations around the world, but they are particularly well defined and prevalent in southern Africa during the dry season August-September). This is because at this time in this region, stable layers are common and pollution from biomass burning is widespread.

  15. Trajectory Synthesis for Fisher Information Maximization

    PubMed Central

    Wilson, Andrew D.; Schultz, Jarvis A.; Murphey, Todd D.

    2015-01-01

    Estimation of model parameters in a dynamic system can be significantly improved with the choice of experimental trajectory. For general nonlinear dynamic systems, finding globally “best” trajectories is typically not feasible; however, given an initial estimate of the model parameters and an initial trajectory, we present a continuous-time optimization method that produces a locally optimal trajectory for parameter estimation in the presence of measurement noise. The optimization algorithm is formulated to find system trajectories that improve a norm on the Fisher information matrix (FIM). A double-pendulum cart apparatus is used to numerically and experimentally validate this technique. In simulation, the optimized trajectory increases the minimum eigenvalue of the FIM by three orders of magnitude, compared with the initial trajectory. Experimental results show that this optimized trajectory translates to an order-of-magnitude improvement in the parameter estimate error in practice. PMID:25598763

  16. Trajectory-Based Complexity (TBX): A Modified Aircraft Count to Predict Sector Complexity During Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Lee, Paul U.

    2011-01-01

    In this paper we introduce a new complexity metric to predict -in real-time- sector complexity for trajectory-based operations (TBO). TBO will be implemented in the Next Generation Air Transportation System (NextGen). Trajectory-Based Complexity (TBX) is a modified aircraft count that can easily be computed and communicated in a TBO environment based upon predictions of aircraft and weather trajectories. TBX is scaled to aircraft count and represents an alternate and additional means to manage air traffic demand and capacity with more consideration of dynamic factors such as weather, aircraft equipage or predicted separation violations, as well as static factors such as sector size. We have developed and evaluated TBX in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center during human-in-the-loop studies of trajectory-based concepts since 2009. In this paper we will describe the TBX computation in detail and present the underlying algorithm. Next, we will describe the specific TBX used in an experiment at NASA's AOL. We will evaluate the performance of this metric using data collected during a controller-inthe- loop study on trajectory-based operations at different equipage levels. In this study controllers were prompted at regular intervals to rate their current workload on a numeric scale. When comparing this real-time workload rating to the TBX values predicted for these time periods we demonstrate that TBX is a better predictor of workload than aircraft count. Furthermore we demonstrate that TBX is well suited to be used for complexity management in TBO and can easily be adjusted to future operational concepts.

  17. Classification of atmospheric river events on the U.S. west coast using a trajectory model

    NASA Astrophysics Data System (ADS)

    Ryoo, J. M.; Waliser, D. E.; Waugh, D. W.; Wong, S.; Fetzer, E. J.; Fung, I. Y.

    2014-12-01

    We investigate transport pathways of water vapor associated with landfalling atmospheric river (AR) events that result in precipitation along the west coast of the U.S. for winter of 1997-2010. The water vapor transport pathways are determined by computing back-trajectories with a trajectory model using the MERRA reanalysis dataset. The majority of AR events (about 86%) over the west coast of the U.S. are associated with three trajectory types. We designate the first type as Ascending near landfall and of Tropical Origin (AT), the second type as Ascending near landfall and of Extratropical Origin (AE), and the third type as Descending or parallel near landfall and of Extratropical Origin (DE). The magnitude and spatial distribution of precipitation of a given AR event are found to be strongly determined by the mixture of its type of trajectories. AR events composed of both AT and AE trajectories have more frequent and intense precipitation over a broad region of the western U.S. (particularly in the northern California) than AR events dominated by a single trajectory type (AT) or other combinations (e.g. AT and DE). In addition, different patterns of trajectory types among AR events are closely linked to the location and the shape of potential vorticity intrusions near the tropopause, which emphasizes that lower tropospheric air is interacting with upper tropospheric air during the developing rainfall system.

  18. Trajectories of Autism Severity in Early Childhood

    ERIC Educational Resources Information Center

    Venker, Courtney E.; Ray-Subramanian, Corey E.; Bolt, Daniel M.; Weismer, Susan Ellis

    2014-01-01

    Relatively little is known about trajectories of autism severity using calibrated severity scores (CSS) from the Autism Diagnostic Observation Schedule, but characterizing these trajectories has important theoretical and clinical implications. This study examined CSS trajectories during early childhood. Participants were 129 children with autism…

  19. Design and Analysis of Optimal Ascent Trajectories for Stratospheric Airships

    NASA Astrophysics Data System (ADS)

    Mueller, Joseph Bernard

    Stratospheric airships are lighter-than-air vehicles that have the potential to provide a long-duration airborne presence at altitudes of 18-22 km. Designed to operate on solar power in the calm portion of the lower stratosphere and above all regulated air traffic and cloud cover, these vehicles represent an emerging platform that resides between conventional aircraft and satellites. A particular challenge for airship operation is the planning of ascent trajectories, as the slow moving vehicle must traverse the high wind region of the jet stream. Due to large changes in wind speed and direction across altitude and the susceptibility of airship motion to wind, the trajectory must be carefully planned, preferably optimized, in order to ensure that the desired station be reached within acceptable performance bounds of flight time and energy consumption. This thesis develops optimal ascent trajectories for stratospheric airships, examines the structure and sensitivity of these solutions, and presents a strategy for onboard guidance. Optimal ascent trajectories are developed that utilize wind energy to achieve minimum-time and minimum-energy flights. The airship is represented by a three-dimensional point mass model, and the equations of motion include aerodynamic lift and drag, vectored thrust, added mass effects, and accelerations due to mass flow rate, wind rates, and Earth rotation. A representative wind profile is developed based on historical meteorological data and measurements. Trajectory optimization is performed by first defining an optimal control problem with both terminal and path constraints, then using direct transcription to develop an approximate nonlinear parameter optimization problem of finite dimension. Optimal ascent trajectories are determined using SNOPT for a variety of upwind, downwind, and crosswind launch locations. Results of extensive optimization solutions illustrate definitive patterns in the ascent path for minimum time flights across

  20. Geometric diffusion of quantum trajectories

    PubMed Central

    Yang, Fan; Liu, Ren-Bao

    2015-01-01

    A quantum object can acquire a geometric phase (such as Berry phases and Aharonov–Bohm phases) when evolving along a path in a parameter space with non-trivial gauge structures. Inherent to quantum evolutions of wavepackets, quantum diffusion occurs along quantum trajectories. Here we show that quantum diffusion can also be geometric as characterized by the imaginary part of a geometric phase. The geometric quantum diffusion results from interference between different instantaneous eigenstate pathways which have different geometric phases during the adiabatic evolution. As a specific example, we study the quantum trajectories of optically excited electron-hole pairs in time-reversal symmetric insulators, driven by an elliptically polarized terahertz field. The imaginary geometric phase manifests itself as elliptical polarization in the terahertz sideband generation. The geometric quantum diffusion adds a new dimension to geometric phases and may have applications in many fields of physics, e.g., transport in topological insulators and novel electro-optical effects. PMID:26178745

  1. Trajectory correction propulsion for TOPS

    NASA Technical Reports Server (NTRS)

    Long, H. R.; Bjorklund, R. A.

    1972-01-01

    A blowdown-pressurized hydrazine propulsion system was selected to provide trajectory correction impulse for outer planet flyby spacecraft as the result of cost/mass/reliability tradeoff analyses. Present hydrazine component and system technology and component designs were evaluated for application to the Thermoelectric Outer Planet Spacecraft (TOPS); while general hydrazine technology was adequate, component design changes were deemed necessary for TOPS-type missions. A prototype hydrazine propulsion system was fabricated and fired nine times for a total of 1600 s to demonstrate the operation and performance of the TOPS propulsion configuration. A flight-weight trajectory correction propulsion subsystem (TCPS) was designed for the TOPS based on actual and estimated advanced components.

  2. Hierarchical Control and Trajectory Planning

    NASA Technical Reports Server (NTRS)

    Martin, Clyde F.; Horn, P. W.

    1994-01-01

    Most of the time on this project was spent on the trajectory planning problem. The construction is equivalent to the classical spline construction in the case that the system matrix is nilpotent. If the dimension of the system is n then the spline of degree 2n-1 is constructed. This gives a new approach to the construction of splines that is more efficient than the usual construction and at the same time allows the construction of a much larger class of splines. All known classes of splines are reconstructed using the approach of linear control theory. As a numerical analysis tool control theory gives a very good tool for constructing splines. However, for the purposes of trajectory planning it is quite another story. Enclosed in this document are four reports done under this grant.

  3. EPOXI Trajectory and Maneuver Analyses

    NASA Technical Reports Server (NTRS)

    Chung, Min-Kun J.; Bhaskaran, Shyamkumar; Chesley, Steven R.; Halsell, C. Allen; Helfrich, Clifford E.; Jefferson, David C.; McElrath, Timothy P.; Rush, Brian P.; Wang, Tseng-Chan M.; Yen, Chen-wan L.

    2011-01-01

    The EPOXI mission is a NASA Discovery Mission of Opportunity combining two separate investigations: Extrasolar Planet Observation and Characterization (EPOCh) and Deep Impact eXtended Investigation (DIXI). Both investigations reused the DI instruments and spacecraft that successfully flew by the comet Tempel-1 (4 July 2005). For EPOCh, the goal was to find exoplanets with the high resolution imager, while for DIXI it was to fly by the comet Hartley 2 (4 Nov 2010). This paper documents the navigation experience of the earlier ma-neuver analyses critical for the EPOXI mission including statistical ?V analyses and other useful analyses in designing maneuvers. It also recounts the trajectory design leading up to the final reference trajectory to Hartley 2.

  4. Nonlinear three-dimensional trajectory following: simulation and application

    NASA Astrophysics Data System (ADS)

    Hines, George H.

    In light of recent military requirements for unmanned and autonomous vehicles, research into methods of designing arbitrary three-dimensional trajectories and controlling aircraft along them has become vital. In this report, we explore two methods of nonlinear control for the purpose of following three-dimensional trajectories and paths. First, prior work on a dynamic feedback linearization exploiting the differential flatness of the ideal airplane is adapted with the intent of implementing it on a physical testbed in MIT's Realtime indoor Autonomous Vehicle test ENvironment (RAVEN), but poor behavior—both in simulation and in hardware—under moderate levels of joint parameter uncertainty thwarted attempts at implementation. Additionally, the differential flatness technique in its pure form follows trajectories, which are sometimes inferior intuitively and practically to paths. In the context of unmanned air vehicle (UAV) flight in gusty environments, this motivated the extension of prior work on two-dimensional path following to three-dimensions, and simulations are presented in which the fully nonlinear controller derived from differential flatness follows a trajectory that is generated dynamically from a path. The three-dimensional path-following logic is actually implemented in RAVEN, and results are presented that demonstrate good vertical rise time in response to a step input and centimeter accuracy in vertical and lateral tracking. Future directions are proposed.

  5. Improving Separation Assurance Stability Through Trajectory Flexibility Preservation

    NASA Technical Reports Server (NTRS)

    Idris, Husni; Shen, Ni; Wing, David J.

    2010-01-01

    New information and automation technologies are enabling the distribution of tasks and decisions from the service providers to the users of the air traffic system, with potential capacity and cost benefits. This distribution of tasks and decisions raises the concern that independent user actions will decrease the predictability and increase the complexity of the traffic system, hence inhibiting and possibly reversing any potential benefits. One such concern is the adverse impact of uncoordinated actions by individual aircraft on the stability of separation assurance. For example, individual aircraft performing self-separation may resolve predicted losses of separation or conflicts with some traffic, only to result in secondary conflicts with other traffic or with the same traffic later in time. In answer to this concern, this paper proposes metrics for preserving user trajectory flexibility to be used in self-separation along with other objectives. The hypothesis is that preserving trajectory flexibility will naturally reduce the creation of secondary conflicts by bringing about implicit coordination between aircraft. The impact of using these metrics on improving self-separation stability is investigated by measuring the impact on secondary conflicts. The scenarios analyzed include aircraft in en route airspace with each aircraft meeting a required time of arrival in a twenty minute time horizon while maintaining separation from the surrounding traffic and using trajectory flexibility metrics to mitigate the risk of secondary conflicts. Preliminary experiments showed promising results in that the trajectory flexibility preservation reduced the potential for secondary conflicts.

  6. Trajectory structures in turbulent plasmas

    SciTech Connect

    Vlad, Madalina; Spineanu, Florin

    2006-11-03

    Particle stochastic advection in two dimensional divergence free velocity fields is studied. The special statistical properties of this process (non-Gaussian distribution, memory effects and quasi-coherent behavior) are determined using a new approach, the nested subensemble method. The effect of the statistics of trajectories on the evolution of drift turbulence in magnetized plasmas is studied. It essentialy consists in the tendency of structure formation.

  7. Fractional Trajectories: Decorrelation Versus Friction

    DTIC Science & Technology

    2013-07-27

    from the integration of fractional differential equations in time. In Section 2 we provide a general demonstration of the new perspective on fractional ...section we demonstrate the equivalence between a fractional trajectory that is the solution of a Caputo fractional differential equation , and the... fractional differential equation dα dtα V(t) = OV(t), (1) where 0 < α < 1 and O is an operator, either linear or nonlinear, acting on the vector V(t

  8. Aircraft flight test trajectory control

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Walker, R. A.

    1988-01-01

    Two control law design techniques are compared and the performance of the resulting controllers evaluated. The design requirement is for a flight test trajectory controller (FTTC) capable of closed-loop, outer-loop control of an F-15 aircraft performing high-quality research flight test maneuvers. The maneuver modeling, linearization, and design methodologies utilized in this research, are detailed. The results of applying these FTTCs to a nonlinear F-15 simulation are presented.

  9. Dynamic Scaling of Manipulator Trajectories.

    DTIC Science & Technology

    1983-01-01

    Manipulators Robotics Trajectory Planning Manipulator Dynamics 20. ABSTRACT (Conftnue wn reverse side ID neceeOor Oine Identlfy b? block nuemNer) A...receives a c factor for each b(i). ’lhus both terms change equally with differing movement speeds. This contradicts the normal assumption in the robotics ...as well since they share the same significance as the velocity terms, yet this is not done. In any case, future generations of robots will contain

  10. Bohmian trajectories of Airy packets

    SciTech Connect

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-15

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space–time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject’s theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  11. Trajectory versus probability density entropy.

    PubMed

    Bologna, M; Grigolini, P; Karagiorgis, M; Rosa, A

    2001-07-01

    We show that the widely accepted conviction that a connection can be established between the probability density entropy and the Kolmogorov-Sinai (KS) entropy is questionable. We adopt the definition of density entropy as a functional of a distribution density whose time evolution is determined by a transport equation, conceived as the only prescription to use for the calculation. Although the transport equation is built up for the purpose of affording a picture equivalent to that stemming from trajectory dynamics, no direct use of trajectory time evolution is allowed, once the transport equation is defined. With this definition in mind we prove that the detection of a time regime of increase of the density entropy with a rate identical to the KS entropy is possible only in a limited number of cases. The proposals made by some authors to establish a connection between the two entropies in general, violate our definition of density entropy and imply the concept of trajectory, which is foreign to that of density entropy.

  12. Perching aerodynamics and trajectory optimization

    NASA Astrophysics Data System (ADS)

    Wickenheiser, Adam; Garcia, Ephrahim

    2007-04-01

    Advances in smart materials, actuators, and control architecture have enabled new flight capabilities for aircraft. Perching is one such capability, described as a vertical landing maneuver using in-flight shape reconfiguration in lieu of high thrust generation. A morphing, perching aircraft design is presented that is capable of post stall flight and very slow landing on a vertical platform. A comprehensive model of the aircraft's aerodynamics, with special regard to nonlinear affects such as flow separation and dynamic stall, is discussed. Trajectory optimization using nonlinear programming techniques is employed to show the effects that morphing and nonlinear aerodynamics have on the maneuver. These effects are shown to decrease the initial height and distance required to initiate the maneuver, reduce the bounds on the trajectory, and decrease the required thrust for the maneuver. Perching trajectories comparing morphing versus fixed-configuration and stalled versus un-stalled aircraft are presented. It is demonstrated that a vertical landing is possible in the absence of high thrust if post-stall flight capabilities and vehicle reconfiguration are utilized.

  13. Designing Asteroid Impact Scenario Trajectories

    NASA Astrophysics Data System (ADS)

    Chodas, Paul

    2016-05-01

    In order to study some of the technical and geopolitical issues of dealing with an asteroid on impact trajectory, a number of hypothetical impact scenarios have been presented over the last ten years or so. These have been used, for example, at several of the Planetary Defense Conferences (PDCs), as well as in tabletop exercises with the Federal Emergency Management Agency (FEMA), along with other government agencies. The exercise at the 2015 PDC involved most of the attendees, consisted of seven distinct steps (“injects”), and with all the presentations and discussions, took up nearly 10 hours of conference time. The trajectory for the PDC15 scenario was entirely realistic, and was posted ahead of the meeting. It was made available in the NEO Program’s Horizons ephemeris service so that users could , for example, design their own deflection missions. The simulated asteroid and trajectory had to meet numerous very exacting requirements: becoming observable on the very first day of the conference, yet remaining very difficult to observe for the following 7 years, and far enough away from Earth that it was out of reach of radar until just before impact. It had to be undetectable in the past, and yet provide multiple perihelion opportunities for deflection in the future. It had to impact in a very specific region of the Earth, a specific number of years after discovery. When observations of the asteroid are simulated to generate an uncertainty region, that entire region must impact the Earth along an axis that cuts across specific regions of the Earth, the “risk corridor”. This is important because asteroid deflections generally move an asteroid impact point along this corridor. One scenario had a requirement that the asteroid pass through a keyhole several years before impact. The PDC15 scenario had an additional constraint that multiple simulated kinetic impactor missions altered the trajectory at a deflection point midway between discovery and impact

  14. Optimal Output Trajectory Redesign for Invertible Systems

    NASA Technical Reports Server (NTRS)

    Devasia, Santosh

    1996-01-01

    Given a desired output trajectory, inversion-based techniques find input-state trajectories required to exactly track the output. These inversion-based techniques have been successfully applied to the endpoint tracking control of multi-joint flexible manipulators and to aircraft control. The specified output trajectory uniquely determines the required input and state trajectories that are found through inversion. These input-state trajectories exactly track the desired output; however, they might not meet acceptable performance requirements. For example, during slewing maneuvers of flexible structures, the structural deformations, which depend on the required state trajectories, may be unacceptably large. Further, the required inputs might cause actuator saturation during an exact tracking maneuver for example, in the flight control of conventional takeoff and landing aircraft. In such situations, a compromise is desired between the tracking requirement and other goals such as reduction of internal vibrations and prevention of actuator saturation; the desired output trajectory needs to be redesigned.

  15. Rapid Design of Gravity Assist Trajectories

    NASA Technical Reports Server (NTRS)

    Carrico, J.; Hooper, H. L.; Roszman, L.; Gramling, C.

    1991-01-01

    Several International Solar Terrestrial Physics (ISTP) missions require the design of complex gravity assisted trajectories in order to investigate the interaction of the solar wind with the Earth's magnetic field. These trajectories present a formidable trajectory design and optimization problem. The philosophy and methodology that enable an analyst to design and analyse such trajectories are discussed. The so called 'floating end point' targeting, which allows the inherently nonlinear multiple body problem to be solved with simple linear techniques, is described. The combination of floating end point targeting with analytic approximations with a Newton method targeter to achieve trajectory design goals quickly, even for the very sensitive double lunar swingby trajectories used by the ISTP missions, is demonstrated. A multiconic orbit integration scheme allows fast and accurate orbit propagation. A prototype software tool, Swingby, built for trajectory design and launch window analysis, is described.

  16. A comparison of HYSPLIT backward trajectories generated from two GDAS datasets.

    PubMed

    Su, Lin; Yuan, Zibing; Fung, Jimmy C H; Lau, Alexis K H

    2015-02-15

    The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model is widely used to generate backward trajectories in given starting locations. However, differences exist between trajectories generated from the model with different input datasets. In this study, backward trajectories in Hong Kong in the entire year of 2011 are derived by HYSPLIT model. Two sets of Global Data Assimilation System (GDAS) output data associated with different horizontal and vertical resolutions (GDAS1 and GDAS0P5) are used as drivers in an attempt to quantify the differences between the results and discover the underlying reasons responsible for discrepancy. The results reveal that the significant differences between back trajectories generated from the two GDAS datasets can be mainly attributed to different vertical velocity calculation methods due to the absence of vertical velocity in GDAS0P5 dataset. The HYSPLIT trajectories are also sensitive to the horizontal and vertical resolutions of the input meteorological data, but to lesser extents. Results of cluster analysis indicate that when the air mass is from the north, northeast, or west with a long-to-medium range, the HYSPLIT backward trajectories are sensitive to the vertical advection calculation method and data resolution, whereas when the air mass is from the south or southwest with a long range, the trajectories are more likely to remain unchanged with the shifting of vertical velocity or data resolution. By comparing the vertical velocities with the observations and the performance in retrieving PM contributions from different directions, we conclude that GDAS1 dataset is more plausible in backward trajectory analysis in the Pearl River Delta.

  17. MESOI: an interactive Lagrangian trajectory puff diffusion model

    SciTech Connect

    Ramsdell, J.V.; Athey, G.F.

    1981-12-01

    MESOI is an interactive Lagrangian trajectory puff diffusion model based on an earlier model by Start and Wendell at the Air Resources Laboratory Field Office at Idaho Falls, Idaho. Puff trajectories are determined using spatially and temporally varying wind fields. Diffusion in the puffs is computed as a function of distance traveled and atmospheric stability. Exposures are computed at nodes of a 31 by 31 grid. There is also provision for interpolation of short term exposures at off-grid locations. This report discusses: the theoretical bases of the model, the numerical approach used in the model, and the sensitivity and accuracy of the model. It contains a description of the computer program and a listing of the code. MESOI is written in FORTRAN. A companion report (Athey, Allwine and Ramsdell, 1981) contains a user's guide to MESOI and documents utility programs that maintain the data files needed by the model.

  18. Fixed-range optimum trajectories for short-haul aircraft

    NASA Technical Reports Server (NTRS)

    Erzberger, H.; Mclean, J. D.; Barman, J. F.

    1975-01-01

    An algorithm, based on the energy-state method, is derived for calculating optimum trajectories with a range constraint. The basis of the algorithm is the assumption that optimum trajectories consist of, at most, three segments: an increasing energy segment (climb); a constant energy segment (cruise); and a decreasing energy segment (descent). This assumption allows energy to be used as the independent variable in the increasing and decreasing energy segments, thereby eliminating the integration of a separate adjoint differential equation and simplifying the calculus of variations problem to one requiring only pointwise extremization of algebraic functions. The algorithm is used to compute minimum fuel, minimum time, and minimum direct-operating-cost trajectories, with range as a parameter, for an in-service CTOL aircraft and for an advanced STOL aircraft. For the CTOL aircraft and the minimum-fuel performance function, the optimum controls, consisting of air-speed and engine power setting, are continuous functions of the energy in both climb and descent as well as near the maximum or cruise energy. This is also true for the STOL aircraft except in the descent where at one energy level a nearly constant energy dive segment occurs, yielding a discontinuity in the airspeed at that energy. The reason for this segment appears to be the relatively high fuel flow at idle power of the engines used by this STOL aircraft. Use of a simplified trajectory which eliminates the dive increases the fuel consumption of the total descent trajectory by about 10 percent and the time to fly the descent by about 19 percent compared to the optimum.

  19. Overshooting thunderstorm cloud top dynamics as approximated by a linear Lagrangian parcel model with analytic exact solutions

    NASA Technical Reports Server (NTRS)

    Schlesinger, Robert E.

    1990-01-01

    Results are presented from a linear Lagrangian entraining parcel model of an overshooting thunderstorm cloud top. The model, which is similar to that of Adler and Mack (1986), gives analytic exact solutions for vertical velocity and temperature by representing mixing with Rayleigh damping instead of nonlinearly. Model results are presented for various combinations of stratospheric lapse rate, drag intensity, and mixing strength. The results are compared to those of Adler and Mack.

  20. Lunar Cube Transfer Trajectory Options

    NASA Technical Reports Server (NTRS)

    Folta, David C.; Dichman, Don; Clark, Pamela; Haapala, Amanda; Howell, Kathleen

    2014-01-01

    Contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these designs can be restricted by the selection of the Cubesat subsystem design such as propulsion or communication. Nonetheless, many trajectory options can be designed with have a wide range of transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several design options including deployment into low Earth orbit (LEO), geostationary transfer orbits (GTO), and higher energy direct lunar transfer orbits. In addition to direct transfer options from these initial orbits, we also investigate the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the trajectory. In this article we examine several design options that meet the above limited deployment and subsystem drivers. We study ways that both impulsive and low-thrust Solar Electric Propulsion (SEP) engines can be used to place the Cubesat first into a highly eccentric Earth orbit, enter the Moon's Sphere of Influence, and finally achieve a highly eccentric lunar orbit. We show that such low-thrust transfers are feasible with a realistic micro-thruster model, assuming that the Cubesat can generate sufficient power for the SEP. Two examples are shown here: (1) A Cubestat injected by Exploration Mission 1 (EM-1) then employing low thrust; and (2) a CubSat deployed in a GTO, then employing impulsive maneuvers. For the EM-1 injected initial design, we increase the EM-1 targeted lunar flyby distance to reduce the energy of the lunar flyby to match that of a typical lMoon system heteroclinic manifold. Figure 1 presents an option that encompasses the similar dynamics as that of the ARTEMIS

  1. Quantum Tunneling and Complex Trajectories

    NASA Astrophysics Data System (ADS)

    Meynig, Max; Haggard, Hal

    2017-01-01

    In general, the semiclassical approximation of quantum mechanical tunneling fails to treat tunneling through barriers if real initial conditions and trajectories are used. By analytically continuing classical dynamics to the complex plane the problems encountered in the approximation can be resolved. While, the complex methods discussed here have been previously explored, no one has exhibited an analytically solvable case. The essential features of the complex method will be discussed in the context of a novel, analytically solvable problem. These methods could be useful in quantum gravity, with applications to the tunneling of spacetime geometries.

  2. Trajectory constraints in qualitative simulation

    SciTech Connect

    Brajnik, G.; Clancy, D.J.

    1996-12-31

    We present a method for specifying temporal constraints on trajectories of dynamical systems and enforcing them during qualitative simulation. This capability can be used to focus a simulation, simulate non-autonomous and piecewise-continuous systems, reason about boundary condition problems and incorporate observations into the simulation. The method has been implemented in TeQSIM, a qualitative simulator that combines the expressive power of qualitative differential equations with temporal logic. It interleaves temporal logic model checking with the simulation to constrain and refine the resulting predicted behaviors and to inject discontinuous changes into the simulation.

  3. Rocket Launch Trajectory Simulations Mechanism

    NASA Technical Reports Server (NTRS)

    Margasahayam, Ravi; Caimi, Raoul E.; Hauss, Sharon; Voska, N. (Technical Monitor)

    2002-01-01

    The design and development of a Trajectory Simulation Mechanism (TSM) for the Launch Systems Testbed (LST) is outlined. In addition to being one-of-a-kind facility in the world, TSM serves as a platform to study the interaction of rocket launch-induced environments and subsequent dynamic effects on the equipment and structures in the close vicinity of the launch pad. For the first time, researchers and academicians alike will be able to perform tests in a laboratory environment and assess the impact of vibroacoustic behavior of structures in a moving rocket scenario on ground equipment, launch vehicle, and its valuable payload or spacecraft.

  4. Driving trajectories in chaotic scattering.

    PubMed

    Macau, Elbert E N; Caldas, Iberê L

    2002-02-01

    In this work we introduce a general approach for targeting in chaotic scattering that can be used to find a transfer trajectory between any two points located inside the scattering region. We show that this method can be used in association with a control of chaos strategy to drive around and keep a particle inside the scattering region. As an illustration of how powerful this approach is, we use it in a case of practical interest in celestial mechanics in which it is desired to control the evolution of two satellites that evolve around a large central body.

  5. Trajectories of depressive symptoms after hip fracture

    PubMed Central

    Cristancho, P.; Lenze, E. J.; Avidan, M. S.; Rawson, K. S.

    2016-01-01

    Background Hip fracture is often complicated by depressive symptoms in older adults. We sought to characterize trajectories of depressive symptoms arising after hip fracture and examine their relationship with functional outcomes and walking ability. We also investigated clinical and psychosocial predictors of these trajectories. Method We enrolled 482 inpatients, aged ≥60 years, who were admitted for hip fracture repair at eight St Louis, MO area hospitals between 2008 and 2012. Participants with current depression diagnosis and/or notable cognitive impairment were excluded. Depressive symptoms and functional recovery were assessed with the Montgomery–Asberg Depression Rating Scale and Functional Recovery Score, respectively, for 52 weeks after fracture. Health, cognitive, and psychosocial variables were gathered at baseline. We modeled depressive symptoms using group-based trajectory analysis and subsequently identified correlates of trajectory group membership. Results Three trajectories emerged according to the course of depressive symptoms, which we termed ‘resilient’, ‘distressed’, and ‘depressed’. The depressed trajectory (10% of participants) experienced a persistently high level of depressive symptoms and a slower time to recover mobility than the other trajectory groups. Stressful life events prior to the fracture, current smoking, higher anxiety, less social support, antidepressant use, past depression, and type of implant predicted membership of the depressed trajectory. Conclusions Depressive symptoms arising after hip fracture are associated with poorer functional status. Clinical and psychosocial variables predicted membership of the depression trajectory. Early identification and intervention of patients in a depressive trajectory may improve functional outcomes after hip fracture. PMID:27032698

  6. Node Detection Using High-Dimensional Fuzzy Parcellation Applied to the Insular Cortex

    PubMed Central

    Vercelli, Ugo; Diano, Matteo; Costa, Tommaso; Nani, Andrea; Duca, Sergio; Geminiani, Giuliano; Vercelli, Alessandro; Cauda, Franco

    2016-01-01

    Several functional connectivity approaches require the definition of a set of regions of interest (ROIs) that act as network nodes. Different methods have been developed to define these nodes and to derive their functional and effective connections, most of which are rather complex. Here we aim to propose a relatively simple “one-step” border detection and ROI estimation procedure employing the fuzzy c-mean clustering algorithm. To test this procedure and to explore insular connectivity beyond the two/three-region model currently proposed in the literature, we parcellated the insular cortex of 20 healthy right-handed volunteers scanned in a resting state. By employing a high-dimensional functional connectivity-based clustering process, we confirmed the two patterns of connectivity previously described. This method revealed a complex pattern of functional connectivity where the two previously detected insular clusters are subdivided into several other networks, some of which are not commonly associated with the insular cortex, such as the default mode network and parts of the dorsal attentional network. Furthermore, the detection of nodes was reliable, as demonstrated by the confirmative analysis performed on a replication group of subjects. PMID:26881093

  7. A comparison of working postures of parcel sorters using three different working methods.

    PubMed

    Derksen, J C; Van Riel, M P; Van Wingerden, J P; Snijders, C J

    1994-02-01

    The postures of the trunk of eight parcel sorters were measured continuously under three different working conditions, during whole shifts. The working methods used were two different sorting tables and a hydraulic lifting platform on which the carts were to be placed. The question posed by the PTT-Post occupational health service was whether the latter method proved to be the better one with respect to the load on the musculoskeletal system. This study will help them to make a well-considered decision on which working method to choose for the new distribution centre in Rotterdam. The method used for measuring the working postures and movements of the trunk is the Portable Posture Registration Set (PPRS). This method was developed at the department of Biomedical Physics and Technology of the Erasmus University Rotterdam. While using the lifting platform, the subjects stood 8-11% more erect compared to the work at the sorting tables, thereby reducing the load on the lumbar spine. For this reason the lifting platform is preferred, although sagittal flexion of the back was somewhat more. It is stressed that the way in which sorters use the lifting platform is very important.

  8. Data model for the collaboration between land administration systems and agricultural land parcel identification systems.

    PubMed

    Inan, Halil Ibrahim; Sagris, Valentina; Devos, Wim; Milenov, Pavel; van Oosterom, Peter; Zevenbergen, Jaap

    2010-12-01

    The Common Agricultural Policy (CAP) of the European Union (EU) has dramatically changed after 1992, and from then on the CAP focused on the management of direct income subsidies instead of production-based subsidies. For this focus, Member States (MS) are expected to establish Integrated Administration and Control System (IACS), including a Land Parcel Identification System (LPIS) as the spatial part of IACS. Different MS have chosen different solutions for their LPIS. Currently, some MS based their IACS/LPIS on data from their Land Administration Systems (LAS), and many others use purpose built special systems for their IACS/LPIS. The issue with these different IACS/LPIS is that they do not have standardized structures; rather, each represents a unique design in each MS, both in the case of LAS based or special systems. In this study, we aim at designing a core data model for those IACS/LPIS based on LAS. For this purpose, we make use of the ongoing standardization initiatives for LAS (Land Administration Domain Model: LADM) and IACS/LPIS (LPIS Core Model: LCM). The data model we propose in this study implies the collaboration between LADM and LCM and includes some extensions. Some basic issues with the collaboration model are discussed within this study: registration of farmers, land use rights and farming limitations, geometry/topology, temporal data management etc. For further explanation of the model structure, sample instance level diagrams illustrating some typical situations are also included.

  9. Parcel-scale urban coastal flood prediction: Identifying critical data and forcing requirements

    NASA Astrophysics Data System (ADS)

    Gallien, T.; Sanders, B. F.

    2012-12-01

    Coastal flooding represents a significant socio-economic and humanitarian threat to urbanized lowlands throughout the world. In California, sea levels are projected to rise 1-1.4 meters in the next century. Numerous coastal communities are currently at risk of flooding during high tides or large wave events and a significant body of evidence suggests climate change will exacerbate flooding in these low lying, and often highly populated, areas. Flood prediction in urbanized embayments pose a number of challenges including water level characterization, appropriate representation of both weir-like (i.e. wall) overflow and wave runup/overtopping volumes and the need for highly accurate local data and site knowledge. In addition, a paucity of high quality validation data fundamentally obstructs predictive flood modeling efforts. Here, a Southern California coastal community which benefits from two unique flood event validation data sets is modeled in context of current and future sea level scenarios. The uncalibrated hydrodynamic model resolves critical urban infrastructure and includes essential dynamic processes such as tidal amplification, weir-like overflow and spatially distributed wave overtopping volumes. Results identify data and forcing requirements that are essential to accurate parcel-scale (individual home or street) flood prediction in defended urban terrain.

  10. Let's Not Waste Time: Using Temporal Information in Clustered Activity Estimation with Spatial Adjacency Restrictions (CAESAR) for Parcellating FMRI Data.

    PubMed

    Janssen, Ronald J; Jylänki, Pasi; van Gerven, Marcel A J

    2016-01-01

    We have proposed a Bayesian approach for functional parcellation of whole-brain FMRI measurements which we call Clustered Activity Estimation with Spatial Adjacency Restrictions (CAESAR). We use distance-dependent Chinese restaurant processes (dd-CRPs) to define a flexible prior which partitions the voxel measurements into clusters whose number and shapes are unknown a priori. With dd-CRPs we can conveniently implement spatial constraints to ensure that our parcellations remain spatially contiguous and thereby physiologically meaningful. In the present work, we extend CAESAR by using Gaussian process (GP) priors to model the temporally smooth haemodynamic signals that give rise to the measured FMRI data. A challenge for GP inference in our setting is the cubic scaling with respect to the number of time points, which can become computationally prohibitive with FMRI measurements, potentially consisting of long time series. As a solution we describe an efficient implementation that is practically as fast as the corresponding time-independent non-GP model with typically-sized FMRI data sets. We also employ a population Monte-Carlo algorithm that can significantly speed up convergence compared to traditional single-chain methods. First we illustrate the benefits of CAESAR and the GP priors with simulated experiments. Next, we demonstrate our approach by parcellating resting state FMRI data measured from twenty participants as taken from the Human Connectome Project data repository. Results show that CAESAR affords highly robust and scalable whole-brain clustering of FMRI timecourses.

  11. Organization and Detailed Parcellation of Human Hippocampal Head and Body Regions Based on a Combined Analysis of Cyto- and Chemoarchitecture.

    PubMed

    Ding, Song-Lin; Van Hoesen, Gary W

    2015-10-15

    The hippocampal formation (HF) is one of the hottest regions in neuroscience because it is critical to learning, memory, and cognition, while being vulnerable to many neurological and mental disorders. With increasing high-resolution imaging techniques, many scientists have started to use distinct landmarks along the anterior-posterior axis of HF to allow segmentation into individual subfields in order to identify specific functions in both normal and diseased conditions. These studies urgently call for more reliable and accurate segmentation of the HF subfields DG, CA3, CA2, CA1, prosubiculum, subiculum, presubiculum, and parasubiculum. Unfortunately, very limited data are available on detailed parcellation of the HF subfields, especially in the complex, curved hippocampal head region. In this study we revealed detailed organization and parcellation of all subfields of the hippocampal head and body regions on the base of a combined analysis of multiple cyto- and chemoarchitectural stains and dense sequential section sampling. We also correlated these subfields to macro-anatomical landmarks, which are visible on magnetic resonance imaging (MRI) scans. Furthermore, we created three versions of the detailed anatomic atlas for the hippocampal head region to account for brains with four, three, or two hippocampal digitations. These results will provide a fundamental basis for understanding the organization, parcellation, and anterior-posterior difference of human HF, facilitating accurate segmentation and measurement of HF subfields in the human brain on MRI scans.

  12. Phase 1 Environmental Baseline Survey, The Landings at Nellis Housing Area, Parcel H, Nellis Air Force Base, Nevada

    DTIC Science & Technology

    2011-06-01

    Cotton St. El Paso TX. 7990 I S:lmJll(• ID #:Chlordane Soil Sample Sample Matrix: Solid Amtlytc Organochlorine Pesticides ChlorJan..: (tcdl) Result...9920 Fax (210) 229-9921 www.satrstinglab.com l’a::•· 2 of J Organochlorine Pesticides- Quality Control R~.!portlng ’ \

  13. Debt trajectories and mental health.

    PubMed

    Hojman, Daniel A; Miranda, Álvaro; Ruiz-Tagle, Jaime

    2016-10-01

    In the last few decades, there was a marked increase in consumer debt in the United States, Latin America and other emerging countries, spurring a debate about the real costs and benefits of household credit. Using a unique longitudinal dataset with detailed health and balance sheet information from a large sample of 10,900 Chilean households we study the relationship between debt trajectories in a three-year time window and mental health. We find that depressive symptoms are higher for those who have been persistently over-indebted, followed by those who transit from moderate to high debt levels. We also find that those who transition from over-indebtedness to moderate debt levels have no additional depressive symptoms compared to those with trajectories of moderate debt throughout (never over-indebted). This suggests that the debt-related contribution to depressive symptoms vanishes as debt levels fall. The association between debt and depressive symptoms seems to be driven by non-mortgage debt -primarily consumer credit- or late mortgage payments; secured debt (secured by collateral) per se is not associated with depressive symptoms. Policy interventions to reduce the negative association of over-indebtedness on mental health are discussed.

  14. TOPTRAC: Topical Trajectory Pattern Mining

    PubMed Central

    Kim, Younghoon; Han, Jiawei; Yuan, Cangzhou

    2015-01-01

    With the increasing use of GPS-enabled mobile phones, geo-tagging, which refers to adding GPS information to media such as micro-blogging messages or photos, has seen a surge in popularity recently. This enables us to not only browse information based on locations, but also discover patterns in the location-based behaviors of users. Many techniques have been developed to find the patterns of people's movements using GPS data, but latent topics in text messages posted with local contexts have not been utilized effectively. In this paper, we present a latent topic-based clustering algorithm to discover patterns in the trajectories of geo-tagged text messages. We propose a novel probabilistic model to capture the semantic regions where people post messages with a coherent topic as well as the patterns of movement between the semantic regions. Based on the model, we develop an efficient inference algorithm to calculate model parameters. By exploiting the estimated model, we next devise a clustering algorithm to find the significant movement patterns that appear frequently in data. Our experiments on real-life data sets show that the proposed algorithm finds diverse and interesting trajectory patterns and identifies the semantic regions in a finer granularity than the traditional geographical clustering methods. PMID:26709365

  15. Discrimination and identification of periodic motion trajectories.

    PubMed

    Or, Charles C-F; Thabet, Michel; Wilkinson, Frances; Wilson, Hugh R

    2011-07-12

    Humans are extremely sensitive to radial deformations of static circular contours (F. Wilkinson, H. R. Wilson, & C. Habak, 1998). Here, we investigate detection and identification of periodic motion trajectories defined by these radial frequency (RF) patterns over a range of radial frequencies of 2-5 cycles. We showed that the average detection thresholds for RF trajectories range from 1 to 4 min of arc and performance improves as a power-law function of radial frequency. RF trajectories are also detected for a range of speeds. We also showed that spatiotemporal global processing is involved in trajectory detection, as improvement in detection performance with increasing radial deformation displayed cannot be accounted for by local probability summation. Finally, identification of RF trajectories is possible over this RF range. Overall thresholds are about 6 times higher than previously reported for static stimuli. These novel stimuli should be a useful tool to investigate motion trajectory learning and discrimination in humans and other primates.

  16. Computer optimization of a linac injector trajectory

    SciTech Connect

    Sawyer, C.; Detch, J.L. Jr.

    1984-01-01

    One can determine a computer prediction of the beam radius as a function of axial distance for a linac beam by providing a set of inputs to the computer code, ZFIELD. The trajectory may be improved by varying the magnet current values in the code, but repeated trails may still not attain the best trajectory. Starting with a set of points containing the desired trajectory, one may work the problem backwards and obtain the necessary magnet currents required by the trajectory. In the examples given, a portion of the trajectory is chosen to be parabolic. The trajectory information is used with a differential equation involving beam radius and its derivatives to yield the magnetic field as a function of axial position. Matrix methods are used to obtain the magnet currents from the magnetic field. 4 references, 6 figures.

  17. Stochastic and fractal analysis of fracture trajectories

    NASA Technical Reports Server (NTRS)

    Bessendorf, Michael H.

    1987-01-01

    Analyses of fracture trajectories are used to investigate structures that fall between 'micro' and 'macro' scales. It was shown that fracture trajectories belong to the class of nonstationary processes. It was also found that correlation distance, which may be related to a characteristic size of a fracture process, increases with crack length. An assemblage of crack trajectory processes may be considered as a diffusive process. Chudnovsky (1981-1985) introduced a 'crack diffusion coefficient' d which reflects the ability of the material to deviate the crack trajectory from the most energetically efficient path and thus links the material toughness to its structure. For the set of fracture trajectories in AISI 304 steel, d was found to be equal to 1.04 microns. The fractal dimension D for the same set of trajectories was found to be 1.133.

  18. On-Line Trajectory Optimization for Autonomous Air Vehicles

    DTIC Science & Technology

    2007-07-31

    equations of motion to handle cooperative path planning for multi-vehicles. • Application of genetic algorithms (GA) to solve multiple initial...1 17 1 165 sinsincos D vDD D uDDD Kg yy y xyy ψ λ ψψ λλ& (2.24) where 32 3 11 AAD = (2.25) 322 AfVfD −= (2.26) y yx ffBVAfffVABAVAD...value was needed, a variable step sweep was employed to find it. Otherwise the GA was used[26-28]. To begin the genetic algorithm, a set of 48

  19. Trajectory specification for high capacity air traffic control

    NASA Technical Reports Server (NTRS)

    Paielli, Russell A. (Inventor)

    2010-01-01

    Method and system for analyzing and processing information on one or more aircraft flight paths, using a four-dimensional coordinate system including three Cartesian or equivalent coordinates (x, y, z) and a fourth coordinate .delta. that corresponds to a distance estimated along a reference flight path to a nearest reference path location corresponding to a present location of the aircraft. Use of the coordinate .delta., rather than elapsed time t, avoids coupling of along-track error into aircraft altitude and reduces effects of errors on an aircraft landing site. Along-track, cross-track and/or altitude errors are estimated and compared with a permitted error bounding space surrounding the reference flight path.

  20. Anomaly Detection and Modeling of Trajectories

    DTIC Science & Technology

    2012-08-01

    unsupervised fashion using support vector machines (SVMs) and various spatial representations of trajectories. This thesis will also focus on...empirically to provide a rich analysis of trajectory datasets. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as...based on the rest of the dataset. This thesis develops a technique for detecting anoma- lous trajectories in a dataset in an unsupervised fashion using

  1. The Jupiter Icy Moons Orbiter reference trajectory

    NASA Technical Reports Server (NTRS)

    Whiffen, Gregory J.; Lam, Try

    2006-01-01

    The proposed NASA Jupiter Icy Moons Orbiter (JIMO) mission would have used a single spacecraft to orbit Callisto, Ganymede, and Europa in succession. The enormous Delta-Velocity required for this mission (nearly [25 km/s]) would necessitate the use of very high efficiency electric propulsion. The trajectory created for the proposed baseline JIMO mission may be the most complex trajectory ever designed. This paper describes the current reference trajectory in detail and describes the processes that were used to construct it.

  2. Trajectory analysis of a soccer ball

    NASA Astrophysics Data System (ADS)

    Goff, John Eric; Carré, Matt J.

    2009-11-01

    We performed experiments in which a soccer ball was launched from a machine while two cameras recorded portions of its trajectory. Drag coefficients were obtained from range measurements for no-spin trajectories, for which the drag coefficient does not vary appreciably during the ball's flight. Lift coefficients were obtained from the trajectories immediately following the ball's launch, in which Reynolds number and spin parameter do not vary much. We obtain two values of the lift coefficient for spin parameters that had not been obtained previously. Our codes for analyzing the trajectories are freely available to educators and students.

  3. NBODY - a multipurpose trajectory optimization computer program

    NASA Technical Reports Server (NTRS)

    Strack, W. C.

    1974-01-01

    Documentation of the NBODY trajectory optimization program is presented in the form of a mathematical development plus a user's manual. Optimal multistage-launch ascent trajectories may be determined by variational thrust steering during the upper phase. Optimal low-thrust interplanetary spacecraft trajectories may also be calculated with solar power or constant power, all-propulsion or embedded coast arcs, fixed or optimal thrust angles, and a variety of terminal end conditions. A hybrid iteration scheme solves the boundary-value problem, while either transversality conditions or a univariate search scheme optimize vehicle or trajectory parameters.

  4. Trajectories of Posttraumatic Stress Among Urban Residents

    PubMed Central

    Galea, Sandro; Uddin, Monica; Koenen, Karestan C.

    2014-01-01

    Urban residents experience a wide range of traumatic events and are at increased risk of assaultive violence. Although previous research has examined trajectories of posttraumatic stress (PTS) through latent class growth analysis (LCGA) among persons exposed to the same index events (e.g., a natural disaster), PTS trajectories have not been documented among urban residents. The aims of this study were to conduct LGCA with a sample of trauma survivors from Detroit, Michigan (N = 981), and to explore predictors of trajectory membership. Participants completed three annual telephone surveys, each of which included the posttraumatic stress disorder (PTSD) Check-list-Civilian Version. Four PTS trajectories were detected. Although the majority evidenced a trajectory of consistently few symptoms (Low: 72.5 %), 4.6 % were in a trajectory of chronic severe PTSD (High), and the remainder were in trajectories of consistently elevated, but generally subclinical, levels of PTS (Decreasing: 12.3 %; Increasing: 10.6 %). Socioeconomic disadvantage (e.g., lower income), more extensive trauma history (e.g., childhood abuse), and fewer social resources (e.g., lower social support) were associated with membership in higher PTS trajectories, relative to the Low trajectory. The results suggest that efforts to reduce PTS in urban areas need to attend to socioeconomic vulnerabilities in addition to trauma history and risk for ongoing trauma exposure. PMID:24469249

  5. Global trajectory targeting via computer graphics

    NASA Technical Reports Server (NTRS)

    Mann, F. I.

    1971-01-01

    A technique is described in which the two-point boundary value problem (TPBVP) may be solved with the aid of interactive computer graphics. The particular TPBVP considered is the optimal electric propulsion space trajectory problem. An appropriate two-dimensional projection of the TPBVP mapping, or trajectory, is displayed on the computer's television screen, and a man-in-the-loop varies selected trajectory starting conditions in the fashion of a nonlinear walk until the viewed trajectory endpoint lies near a displayed target. Once global targeting is accomplished in this manner, program internal logic can easily handle local targeting to strongly solve the TPBVP.

  6. Analysis of Suborbital Launch Trajectories for Satellite Delivery

    DTIC Science & Technology

    1991-12-01

    trajectory, the transition point occurs at a. speed ratio of .876 and an altitude ratio of .279. These values correspond to a velocity of 22403 ft/sec...Transition Altitude 146,404 ft3 Transition Velocity 22403 ft/sec .AV segment 1 22,61 ift/sec Orbit Altitude 100 nm AV segment 2 3,718 ft/sec Dynamic...Consumption during 186,271 Ibm Air Breathing phase Propellant Consumption during 52,831 lbm Rocket Powered phase Transition Velocity 22403 ft/sec (Mach

  7. The Relationship of Loss, Mean Age of Air and the Distribution of CFC's to Stratospheric Circulation and Implications for Atmospheric Lifetimes

    NASA Technical Reports Server (NTRS)

    Douglas, A. R.; Stolarski, R. S.; Schoeberl, M. R.; Jackman, C. H.; Gupta, M. L.; Newman, P. A.; Nielsen, J. E.; Fleming, E. L.

    2008-01-01

    Model-derived estimates of the annually integrated destruction and lifetime for various ozone depleting substances (ODSs) depend on the simulated stratospheric transport and mixing in the global model used to produce the estimate. Observations in the middle and high latitude lower stratosphere show that the mean age of an air parcel (i.e., the time since its stratospheric entry) is related to the fractional release for the ODs (i.e., the amount of the ODS that has been destroyed relative to the amount at the time of stratospheric entry). We use back trajectory calculations to produce an age spectrum, and explain the relationship between the mean age and the fractional release by showing that older elements in the age spectrum have experienced higher altitudes and greater ODs destruction than younger elements. In our study, models with faster circulations produce distributions for the age-of-air that are 'young' compared to a distribution derived from observations. These models also fail to reproduce the observed relationship between the mean age of air and the fractional release. Models with slower circulations produce both realistic distributions for mean age and a realistic relationship between mean age and fractional release. These models also produce a CFCl3 lifetime of approximately 56 years, longer than the 45 year lifetime used to project future mixing ratios. We find that the use of flux boundary conditions in assessment models would have several advantages, including consistency between ODS evolution and simulated loss even if the simulated residual circulation changes due to climate change.

  8. Nonadiabatic Molecular Dynamics with Trajectories

    NASA Astrophysics Data System (ADS)

    Tavernelli, Ivano

    2012-02-01

    In the mixed quantum-classical description of molecular systems, only the quantum character of the electronic degrees of freedom is considered while the nuclear motion is treated at a classical level. In the adiabatic case, this picture corresponds to the Born-Oppenheimer limit where the nuclei move as point charges on the potential energy surface (PES) associated with a given electronic state. Despite the success of this approximation, many physical and chemical processes do not fall in the regime where nuclei and electrons can be considered decoupled. In particular, most photoreactions pass through regions of the PES in which electron-nuclear quantum interference effects are sizeable and often crucial for a correct description of the phenomena. Recently, we have developed a trajectory-based nonadiabatic molecular dynamics scheme that describes the nuclear wavepacket as an ensemble of particles following classical trajectories on PESs derived from time-dependent density functional theory (TDDFT) [1]. The method is based on Tully's fewest switches trajectories surface hopping (TSH) where the nonadiabatic coupling elements between the different potential energy surfaces are computed on-the-fly as functionals of the ground state electron density or, equivalently, of the corresponding Kohn-Sham orbitals [2]. Here, we present the theoretical fundamentals of our approach together with an extension that allows for the direct coupling of the dynamics to an external electromagnetic field [3] as well as to the external potential generated by the environment (solvent effects) [4]. The method is applied to the study of the photodissociation dynamics of simple molecules in gas phase and to the description of the fast excited state dynamics of molecules in solution (in particular Ruthenium (II) tris(bipyridine) in water). [4pt] [1] E. Tapavicza, I. Tavernelli, U. Rothlisberger, Phys. Rev. Lett., 98, (2007) 023001. [0pt] [2] Tavernelli I.; Tapavicza E.; Rothlisberger U., J. Chem

  9. Low-thrust rocket trajectories

    SciTech Connect

    Keaton, P.W.

    1986-01-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report. 57 refs., 10 figs.

  10. Low-thrust rocket trajectories

    SciTech Connect

    Keaton, P.W.

    1987-03-01

    The development of low-thrust propulsion systems to complement chemical propulsion systems will greatly enhance the evolution of future space programs. Two advantages of low-thrust rockets are stressed: first, in a strong gravitational field, such as occurs near the Earth, freighter missions with low-thrust engines require one-tenth as much propellant as do chemical engines. Second, in a weak gravitational field, such as occurs in the region between Venus and Mars, low-thrust rockets are faster than chemical rockets with comparable propellant mass. The purpose here is to address the physics of low-thrust trajectories and to interpret the results with two simple models. Analytic analyses are used where possible - otherwise, the results of numerical calculations are presented in graphs. The author has attempted to make this a self-contained report.

  11. Parametric studies of contrail ice particle formation in jet regime using microphysical parcel modeling

    NASA Astrophysics Data System (ADS)

    Wong, H.-W.; Miake-Lye, R. C.

    2010-04-01

    Condensation trails (contrails) formed from water vapor emissions behind aircraft engines are the most uncertain components of the aviation impacts on climate change. To gain improved knowledge of contrail and contrail-induced cirrus cloud formation, understanding of contrail ice particle formation immediately after aircraft engines is needed. Despite many efforts spent in modeling the microphysics of ice crystal formation in jet regime (with a plume age <5 s), systematic understanding of parametric effects of variables affecting contrail ice particle formation is still limited. In this work, we apply a microphysical parcel modeling approach to study contrail ice particle formation in near-field aircraft plumes up to 1000 m downstream of an aircraft engine in the soot-rich regime (soot number emission index >1×1015 (kg-fuel)-1) at cruise. The effects of dilution history, ion-mediated nucleation, ambient relative humidity, fuel sulfur contents, and initial soot emissions were investigated. Our simulation results suggest that ice particles are mainly formed by water condensation on emitted soot particles. The growth of ice coated soot particles is driven by water vapor emissions in the first 1000 m and by ambient relative humidity afterwards. The presence of chemi-ions does not significantly contribute to the formation of ice particles in the soot-rich regime, and the effect of fuel sulfur contents is small over the range typical of standard jet fuels. The initial properties of soot emissions play the most critical role, and our calculations suggest that higher number concentration and smaller size of contrail particle nuclei may be able to effectively suppress the formation of contrail ice particles. Further modeling and experimental studies are needed to verify if our findings can provide a possible approach for contrail mitigation.

  12. Project Overview: United Parcel Service's Second-Generation Hybrid-Electric Delivery Vans (Fact Sheet)

    SciTech Connect

    Not Available

    2011-11-01

    This fact sheet describes UPS second generation hybrid-electric delivery vehicles as compared to conventional delivery vehicles. Medium-duty commercial vehicles such as moving trucks, beverage-delivery trucks, and package-delivery vans consume almost 2,000 gal of fuel per year on average. United Parcel Service (UPS) operates hybrid-electric package-delivery vans to reduce the fuel use and emissions of its fleet. In 2008, the National Renewable Energy Laboratory's (NREL's) Fleet Test and Evaluation Team evaluated the first generation of UPS' hybrid delivery vans. These hybrid vans demonstrated 29%-37% higher fuel economy than comparable conventional diesel vans, which contributed to UPS' decision to add second-generation hybrid vans to its fleet. The Fleet Test and Evaluation Team is now evaluating the 18-month, in-service performance of 11 second-generation hybrid vans and 11 comparable conventional diesel vans operated by UPS in Minneapolis, Minnesota. The evaluation also includes testing fuel economy and emissions at NREL's Renewable Fuels and Lubricants (ReFUEL) Laboratory and comparing diesel particulate filter (DPF) regeneration. In addition, a followup evaluation of UPS' first-generation hybrid vans will show how those vehicles performed over three years of operation. One goal of this project is to provide a consistent comparison of fuel economy and operating costs between the second-generation hybrid vans and comparable conventional vans. Additional goals include quantifying the effects of hybridization on DPF regeneration and helping UPS select delivery routes for its hybrid vans that maximize the benefits of hybrid technology. This document introduces the UPS second-generation hybrid evaluation project. Final results will be available in mid-2012.

  13. Deducing logical relationships between spatially registered cortical parcellations under conditions of uncertainty.

    PubMed

    Bezgin, Gleb; Wanke, Egon; Krumnack, Antje; Kötter, Rolf

    2008-10-01

    We propose a new technique, called Spatial Objective Relational Transformation (SORT), as an automated approach for derivation of logical relationships between cortical areas in different brain maps registered in the same Euclidean space. Recently, there have been large amounts of voxel-based three-dimensional structural and functional imaging data that provide us with coordinate-based information about the location of differently defined areas in the brain, whereas coordinate-independent, parcellation-based mapping is still commonly used in the majority of animal tracing and mapping studies. Because of the impact of voxel-based imaging methods and the need to attribute their features to coordinate-independent brain entities, this mapping becomes increasingly important. Our motivation here is not to make vague statements where more precise spatial statements would be better, but to find criteria for the identity (or other logical relationships) between areas that were delineated by different methods, in different individuals, or mapped to three-dimensional space using different deformation algorithms. The relevance of this problem becomes immediately obvious as one superimposes and compares different datasets in multimodal databases (e.g. CARET, http://brainmap.wustl.edu/caret), where voxel-based data are registered to surface nodes exploited by the procedure presented here. We describe the SORT algorithm and its implementation in the Java 2 programming language (http://java.sun.com/, which we make available for download. We give an example of practical use of our approach, and validate the SORT approach against a database of the coordinate-independent statements and inferences that have been deduced using alternative techniques.

  14. Freezing Behavior of Stratospheric Sulfate Aerosols Inferred from Trajectory Studies

    NASA Technical Reports Server (NTRS)

    Tabazadeh, A.; Toon, O. B.; Hamill, Patrick

    1995-01-01

    Based on the trajectory analysis presented in this paper, a new mechanism is described for the freezing of the stratospheric sulfate aerosols. Temperature histories based on 10-day back trajectories for six ER-2 flights during AASE-I (1989) and AAOE (1987) are presented. The mechanism requires, as an initial step, the cooling of a H2SO4/H2O aerosol to low temperatures. If a cooling cycle is then followed up by a warming to approximately 196-198 K, the aerosols may freeze due to the growth of the crystallizing embryos formed at the colder temperature. The HNO3 absorbed at colder temperatures may increase the nucleation rate of the crystalling embryos and therefore influence the crystallization of the supercooled aerosols upon warming. Of all the ER-2 flights described, only the polar stratospheric clouds (PSC), observed on the flights of January 24, and 25, 1989 are consistent with the thermodynamics of liquid ternary solutions of H2SO4/HNO3/H2O (type Ib PSCs). For those two days, back trajectories indicate that the air mass was exposed to sulfuric acid tetrahydrate (SAT) melting temperatures about 24 hours prior to being sampled by the ER-2. Temperature histories, recent laboratory measurements, and the properties of glassy solids suggest that stratospheric H2SO4 aerosols may undergo a phase transition to SAT upon warming at approximately 198 K after going through a cooling cycle to about 194 K or lower.

  15. Challenges in Modeling and Measuring Learning Trajectories

    ERIC Educational Resources Information Center

    Confrey, Jere; Jones, R. Seth; Gianopulos, Garron

    2015-01-01

    Briggs and Peck make a compelling case for creating new, more intuitive measures of learning, based on creating vertical scales using learning trajectories (LT) in place of "domain sampling." We believe that the importance of creating measurement scales that coordinate recognizable landmarks in learning trajectories with interval scales…

  16. Variation in Trajectories of Women's Marital Quality

    PubMed Central

    James, Spencer L.

    2014-01-01

    I examine variation in trajectories of women's marital quality across the life course. The analysis improves upon earlier research in three ways: (1) the analysis uses a sequential cohort design and data from the first 35 years of marriage; (2) I analyze rich data from a national sample; (3) I examine multiple dimensions of marital quality. Latent class growth analyses estimated on data from women in the National Longitudinal Survey of Youth-1979 (N = 2604) suggest multiple trajectories for each of three dimensions of marital quality, including two trajectories of marital happiness, two trajectories of marital communication, and three trajectories of marital conflict. Socioeconomic and demographic covariates are then used to illustrate how factors such as income, cohabitation, and race-ethnicity set individuals at risk of poor marital quality throughout the life course by differentiating between high and low trajectories of marital quality. Women on low marital quality trajectories are, as expected, at much greater risk of divorce. Taken together, these findings show how fundamental socioeconomic and demographic characteristics contribute to subsequent marital outcomes via their influence on trajectories of marital quality as well as providing a better picture of the complexity in contemporary patterns of marital quality. PMID:25432600

  17. Guidance trajectories for aeroassisted orbital transfer

    NASA Technical Reports Server (NTRS)

    Miele, A.

    1990-01-01

    Research on aerobraking guidance schemes is presented. The intent is to produce aerobraking guidance trajectories exhibiting many of the desirable characteristics of optimal aerobraking trajectories. Both one-control schemes and two-control schemes are studied. The research is in the interest of aeroassisted flight experiment vehicles (AFE) and aeroassisted orbital transfer (AOT) vehicles.

  18. Projecting uncertainty onto marine megafauna trajectories

    NASA Astrophysics Data System (ADS)

    Robel, Alexander A.; Susan Lozier, M.; Gary, Stefan F.; Shillinger, George L.; Bailey, Helen; Bograd, Steven J.

    2011-09-01

    In this study, a method is proposed for estimating the uncertainty of a Lagrangian pathway calculated from an undersampled ocean surface velocity field. The primary motivation and application for this method is the differentiation between active and passive movements for sea turtles whose trajectories are observed with satellite telemetry. Synthetic trajectories are launched within a reconstructed surface velocity field and integrated forward in time to produce likely trajectories of an actual turtle or drifter. Uncertainties in both the initial conditions at launch and the velocity field along the trajectory are used to yield an envelope of possible synthetic trajectories for each actual trajectory. The juxtaposition of the actual trajectory with the resulting cloud of synthetic trajectories provides a means to distinguish between active and passive movements of the turtle. The uncertainty estimates provided by this model may lead to improvements in our understanding of where and when turtles are engaged in specific behaviors (i.e. migration vs. foraging)—for which potential management efforts may vary accordingly.

  19. Soccer Ball Lift Coefficients via Trajectory Analysis

    ERIC Educational Resources Information Center

    Goff, John Eric; Carre, Matt J.

    2010-01-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin…

  20. Minimum jerk trajectory planning for robotic manipulators

    NASA Technical Reports Server (NTRS)

    Kyriakopoulos, K. J.; Saridis, G. N.

    1991-01-01

    It has been experimentally verified that the jerk of the desired trajectory adversely affects the performance of the tracking control algorithms for robotic manipulators. In this paper, the reasons behind this effect are investigated, and an optimization problem that minimizes joint jerk over a prespecified Cartesian space trajectory is stated. The necessary conditions are derived, and a numerical algorithm is presented.

  1. Simulation of Airplane and Rocket Trajectories

    NASA Technical Reports Server (NTRS)

    Wahbah, Magdy M.; Berning, Michael J.; Choy, Tony S.

    1987-01-01

    Simulation and Optimization of Rocket Trajectories program (SORT) contains comprehensive mathematical models for simulating aircraft dynamics, freely falling objects, and many types of ballistic trajectories. Provides high-fidelity, three-degrees-of-freedom simulation for atmospheric and exoatmospheric flight. It numerically models vehicle subsystems and vehicle environment. Used for wide range of simulations. Written in machine-independent FORTRAN 77.

  2. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... a programmed thrust termination. (3) For launch vehicles flown with a flight safety system, a... OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.207 Trajectory analysis. (a) General. A flight safety analysis must include a trajectory analysis that establishes: (1) For any...

  3. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... a programmed thrust termination. (3) For launch vehicles flown with a flight safety system, a... OF TRANSPORTATION LICENSING LAUNCH SAFETY Flight Safety Analysis § 417.207 Trajectory analysis. (a) General. A flight safety analysis must include a trajectory analysis that establishes: (1) For any...

  4. Variation in trajectories of women's marital quality.

    PubMed

    James, Spencer L

    2015-01-01

    I examine variation in trajectories of women's marital quality across the life course. The analysis improves upon earlier research in three ways: (1) the analysis uses a sequential cohort design and data from the first 35years of marriage; (2) I analyze rich data from a national sample; (3) I examine multiple dimensions of marital quality. Latent class growth analyses estimated on data from women in the National Longitudinal Survey of Youth-1979 (N=2604) suggest multiple trajectories for each of three dimensions of marital quality, including two trajectories of marital happiness, two trajectories of marital communication, and three trajectories of marital conflict. Socioeconomic and demographic covariates are then used to illustrate how factors such as income, cohabitation, and race-ethnicity set individuals at risk of poor marital quality throughout the life course by differentiating between high and low trajectories of marital quality. Women on low marital quality trajectories are, as expected, at much greater risk of divorce. Taken together, these findings show how fundamental socioeconomic and demographic characteristics contribute to subsequent marital outcomes via their influence on trajectories of marital quality as well as providing a better picture of the complexity in contemporary patterns of marital quality.

  5. Trajectories of Delinquency and Parenting Styles

    ERIC Educational Resources Information Center

    Hoeve, Machteld; Blokland, Arjan; Dubas, Judith Semon; Loeber, Rolf; Gerris, Jan R. M.; van der Laan, Peter H.

    2008-01-01

    We investigated trajectories of adolescent delinquent development using data from the Pittsburgh Youth Study and examined the extent to which these different trajectories are differentially predicted by childhood parenting styles. Based on self-reported and official delinquency seriousness, covering ages 10-19, we identified five distinct…

  6. Application of Taylor's series to trajectory propagation

    NASA Technical Reports Server (NTRS)

    Stanford, R. H.; Berryman, K. W.; Breckheimer, P. J.

    1986-01-01

    This paper describes the propagation of trajectories by the application of the preprocessor ATOMCC which uses Taylor's series to solve initial value problems in ordinary differential equations. Comparison of the results obtained with those from other methods are presented. The current studies indicate that the ATOMCC preprocessor is an easy, yet fast and accurate method for generating trajectories.

  7. 77 FR 60334 - New Marking Standards for Parcels Containing Hazardous Materials

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... class 4 materials in its air transportation networks. These mailpieces will also be required to bear the... being tendered for transport within USPS networks, either by surface or air, and all mailpieces... intended for transportation in USPS ground networks. Comment Period Note that the Postal Service...

  8. Assessing land-use history for reporting on cropland dynamics - A case study using the Land-Parcel Identification System in Ireland

    NASA Astrophysics Data System (ADS)

    Zimmermann, Jesko; González, Ainhoa; Jones, Michael; O'Brien, Phillip; Stout, Jane C.; Green, Stuart

    2016-04-01

    In developed countries, cropland and grassland conversions and management can be a major factor in Land Use and Land Use Change (LULUC) related Greenhouse Gas (GHG) dynamics. Depending on land use, management and factors such as soil properties land can either act as source or sink for GHGs. Currently many countries depend on national statistics combined with socio-economic modelling to assess current land use as well as inter-annual changes. This potentially introduces a bias as it neither provides information on direct land- use change trajectories nor spatially explicit information to assess the environmental context. In order to improve reporting countries are shifting towards high resolution spatial datasets. In this case study, we used the Land Parcel Identification System (LPIS), a pan-European geographical database developed to assist farmers and authorities with agricultural subsidies, to analyse cropland dynamics in Ireland. The database offer high spatial resolution and is updated annually. Generally Ireland is considered grassland dominated with 90 % of its agricultural area under permanent grassland, and only a small area dedicated to cropland. However an in-depth analysis of the LPIS for the years 2000 to 2012 showed strong underlying dynamics. While the annual area reported as cropland remained relatively constant at 3752.3 ± 542.3 km2, the area of permanent cropland was only 1251.9 km2. Reversely, the area that was reported as cropland for at least one year during the timeframe was 7373.4 km2, revealing a significantly higher area with cropland history than annual statistics would suggest. Furthermore, the analysis showed that one quarter of the land converting from or to cropland will return to the previous land use within a year. To demonstrate potential policy impact, we assessed cropland/grassland dynamics from the 2008 to 2012 commitment period using (a) annual statistics, and (b) data including land use history derived from LPIS. Under

  9. Multi Sector Planning Tools for Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mainini, Matthew; Brasil, Connie

    2010-01-01

    This paper discusses a suite of multi sector planning tools for trajectory-based operations that were developed and evaluated in the Airspace Operations Laboratory (AOL) at the NASA Ames Research Center. The toolset included tools for traffic load and complexity assessment as well as trajectory planning and coordination. The situation assessment tools included an integrated suite of interactive traffic displays, load tables, load graphs, and dynamic aircraft filters. The planning toolset allowed for single and multi aircraft trajectory planning and data communication-based coordination of trajectories between operators. Also newly introduced was a real-time computation of sector complexity into the toolset that operators could use in lieu of aircraft count to better estimate and manage sector workload, especially in situations with convective weather. The tools were used during a joint NASA/FAA multi sector planner simulation in the AOL in 2009 that had multiple objectives with the assessment of the effectiveness of the tools being one of them. Current air traffic control operators who were experienced as area supervisors and traffic management coordinators used the tools throughout the simulation and provided their usefulness and usability ratings in post simulation questionnaires. This paper presents these subjective assessments as well as the actual usage data that was collected during the simulation. The toolset was rated very useful and usable overall. Many elements received high scores by the operators and were used frequently and successfully. Other functions were not used at all, but various requests for new functions and capabilities were received that could be added to the toolset.

  10. Housing Trajectories of Forensic Psychiatric Patients.

    PubMed

    Salem, Leila; Crocker, Anne G; Charette, Yanick; Earls, Christopher M; Nicholls, Tonia L; Seto, Michael C

    2016-03-01

    The objectives of this study were to describe the disposition and housing trajectories of individuals found Not Criminally Responsible on account of Mental Disorder (NCRMD), and the factors that predict different trajectories. To do so, disposition and housing status were coded for 934 NCRMD patients over a 36-month follow-up period. Sequential data analysis resulted in four distinct trajectories: detention in hospital, conditional discharge in supportive housing, conditional discharge in independent housing, and absolute discharge to unknown housing. The likelihood of a placement in supportive housing compared with detention significantly decreased for individuals with a higher index offense severity. Less restrictive trajectories were significantly predicted by clinical factors. The results revealed little change in the disposition and housing trajectories of NCRMD patients. Furthermore, decisions about disposition and housing placement reflect a knowledge-practice gap between risk factors known to be predictive of community resources use in the forensic population. Copyright © 2016 John Wiley & Sons, Ltd.

  11. Phase I Archaeological Survey of Parcel ED-3 and Historic Assessement of the Happy Valley Worker Camp Roane County, Tennessee

    SciTech Connect

    New South Associates

    2009-08-17

    Parcel ED-3 was the location of a portion of 'Happy Valley', a temporary worker housing area occupied from 1943 to 1947 during the construction of the K-25 Oak Ridge Gaseous Diffusion Plant. The project was carried out under subcontract for the Department of Energy. The survey report will be used in the preparation of an Environmental Assessment under the National Environmental Policy Act (NEPA). New South Associates conducted a Phase I Archaeological Survey of Parcel ED-3 at the US Department of Energy's Oak Ridge Reservation in Roane County, Tennessee. The survey was conducted in two parts. The first survey was carried out in 2008 and covered an area measuring approximately 110 acres. The second survey took place in 2009 and focused on 72 acres west of the first survey area. The objective of the surveys was to identify any archaeological remains associated with Happy Valley and any additional sites on the property and to assess these sites for National Register eligibility. New South Associates also conducted a historic assessment to gather information on Happy Valley. This historic assessment was used in conjunction with the archaeological survey to evaluate the significance of the Happy Valley site. Archaeological remains of Happy Valley were located throughout the parcel, but no additional sites were located. The official state site number for Happy Valley is 40RE577. During the two surveys a total of 13 artifact concentrations, 14 isolated finds, and 75 structural features were located. Due to the Happy Valley's stron gassociation with the Manhattan Project, the site is recommended eligible for the National Register of Historic Places under Criterion A.

  12. Convective sources of trajectories traversing the tropical tropopause layer

    NASA Astrophysics Data System (ADS)

    Tissier, Ann-Sophie; Legras, Bernard

    2016-03-01

    Transit properties across the tropical tropopause layer are studied using extensive forward and backward Lagrangian diabatic trajectories between cloud tops and the reference surface 380 K. After dividing the tropical domain into 11 subregions according to the distribution of land and convection, we estimate the contribution of each region to the upward mass flux across the 380 K surface and to the vertical distribution of convective sources and transit times over the period 2005-2008. The good agreement between forward and backward statistics is the basis of the results presented here. It is found that about 85 % of the tropical parcels at 380 K originate from convective sources throughout the year. From November to April, the sources are dominated by the warm pool which accounts for up to 70 % of the upward flux. During boreal summer, the Asian monsoon region is the largest contributor with similar contributions from the maritime and continental parts of the region; however, the vertical distributions and transit times associated with these two subregions are very different. Convective sources are generally higher over the continental part of the Asian monsoon region, with shorter transit times. We estimate the monthly averaged upward mass flux on the 380 K surface and show that the contribution from convective outflow accounts for 80 % on average and explains most of its seasonal variations. The largest contributor to the convective flux is the South Asian Pacific region (warm pool) at 39 % throughout the year followed by oceanic regions surrounding continental Asia at 18 % and Africa at 10.8 %. Continental Asian lowlands account for 8 %. The Tibetan Plateau is a minor overall contributor (0.8 %), but transport from convective sources in this region is very efficient due to its central location beneath the Asian upper level anticyclone. The core results are robust to uncertainties in data and methods, but the vertical source distributions and transit times

  13. Orbiter Trajectory Analysis for a Two-Stage Reusable Launch Vehicle

    NASA Technical Reports Server (NTRS)

    Cowling, Adam L.

    2011-01-01

    Trajectory analysis performed on NASA's reference two-stage-to-orbit launch vehicle upper stage will be presented. The work was completed in support of the Hypersonics Multidisciplinary Analysis and Optimization effort for the NASA-Air Force Joint System Study. Three degree-of-freedom (3-DOF) untrimmed trajectory analysis was performed for the orbiter ascent, closure and re-entry. An iterative closure process resulted in a 333,000 lb initial mass for the orbiter. The re-entry trajectory satisfied heating constraints for all payload out cases and met the constraints with reduced margins for payload in cases. Abort trajectories for engine out at staging, engine out during ascent, and failure to circularize in orbit, gave insight to the robustness of the orbiter. A trimmed ascent trajectory defined an engine gimbal location and the body flap angle best suited for maximizing injected mass. A trimmed re-entry trajectory revealed a need to update the trim routine to accommodate full flap aerodynamic data.

  14. Evolution of Southern Hemisphere spring air masses observed by HALOE

    NASA Technical Reports Server (NTRS)

    Pierce, R. Bradley; Grose, William L.; Russell, James M., III; Tuck, Adrian F.

    1994-01-01

    The evolution of Southern Hemisphere air masses observed by the Halogen Occultation Experiment (HALOE) during September 21 through October 15, 1992, is investigated using isentropic trajectories computed from United Kingdom Meteorological Office (UKMO) assimilated winds and temperatures. Maps of constituent concentrations are obtained by accumulation of air masses from previous HALOE occultations. Lagged correlations between initial and subsequent HALOE observations of the same air mass are used to validate the air mass trajectories. High correlations are found for lag times as large as 10 days. Frequency distributions of the air mass constituent concentrations are used to examine constituent distributions in and around the Southern Hemisphere polar vortex.

  15. Challenges in Achieving Trajectory-Based Operations

    NASA Technical Reports Server (NTRS)

    Cate, Karen Tung

    2012-01-01

    In the past few years much of the global ATM research community has proposed advanced systems based on Trajectory-Based Operations (TBO). The concept of TBO uses four-dimensional aircraft trajectories as the base information for managing safety and capacity. Both the US and European advanced ATM programs call for the sharing of trajectory data across different decision support tools for successful operations. However, the actual integration of TBO systems presents many challenges. Trajectory predictors are built to meet the specific needs of a particular system and are not always compatible with others. Two case studies are presented which examine the challenges of introducing a new concept into two legacy systems in regards to their trajectory prediction software. The first case describes the issues with integrating a new decision support tool with a legacy operational system which overlap in domain space. These tools perform similar functions but are driven by different requirements. The difference in the resulting trajectories can lead to conflicting advisories. The second case looks at integrating this same new tool with a legacy system originally developed as an integrated system, but diverged many years ago. Both cases illustrate how the lack of common architecture concepts for the trajectory predictors added cost and complexity to the integration efforts.

  16. Six Developmental Trajectories Characterize Children With Autism

    PubMed Central

    Fountain, Christine; Winter, Alix S.

    2012-01-01

    OBJECTIVE: The goal of this study was to describe the typical longitudinal developmental trajectories of social and communication functioning in children with autism and to determine the correlates of these trajectories. METHODS: Children with autism who were born in California from 1992 through 2001 and enrolled with the California Department of Developmental Services were identified. Subjects with <4 evaluations present in the database were excluded, resulting in a sample of 6975 children aged 2 to 14 years. Score sequences were constructed based on 9 evaluative items for social, communication, and repetitive behavior functioning. Typical trajectories were identified by using group-based latent trajectory modeling, and multinomial logistic regression models were used to determine the odds of classification within each trajectory varied by individual and family-level factors. RESULTS: Six typical patterns of social, communication, and repetitive behavior functioning were identified. These trajectories displayed significant heterogeneity in developmental pathways, and children whose symptoms were least severe at first diagnosis tended to improve more rapidly than those severely affected. One group of ∼10% of children experienced rapid gains, moving from severely affected to high functioning. Socioeconomic factors were correlated with trajectory outcomes; children with non-Hispanic, white, well-educated mothers were more likely to be high functioning, and minority children with less-educated mothers or intellectual disabilities were very unlikely to experience rapid gains. CONCLUSIONS: Children with autism have heterogeneous developmental pathways. One group of children evidenced remarkable developmental change over time. Understanding what drives these outcomes is thus critical. PMID:22473372

  17. Trajectory Based Behavior Analysis for User Verification

    NASA Astrophysics Data System (ADS)

    Pao, Hsing-Kuo; Lin, Hong-Yi; Chen, Kuan-Ta; Fadlil, Junaidillah

    Many of our activities on computer need a verification step for authorized access. The goal of verification is to tell apart the true account owner from intruders. We propose a general approach for user verification based on user trajectory inputs. The approach is labor-free for users and is likely to avoid the possible copy or simulation from other non-authorized users or even automatic programs like bots. Our study focuses on finding the hidden patterns embedded in the trajectories produced by account users. We employ a Markov chain model with Gaussian distribution in its transitions to describe the behavior in the trajectory. To distinguish between two trajectories, we propose a novel dissimilarity measure combined with a manifold learnt tuning for catching the pairwise relationship. Based on the pairwise relationship, we plug-in any effective classification or clustering methods for the detection of unauthorized access. The method can also be applied for the task of recognition, predicting the trajectory type without pre-defined identity. Given a trajectory input, the results show that the proposed method can accurately verify the user identity, or suggest whom owns the trajectory if the input identity is not provided.

  18. Comparison of statistical clustering techniques for the classification of modelled atmospheric trajectories

    NASA Astrophysics Data System (ADS)

    Kassomenos, P.; Vardoulakis, S.; Borge, R.; Lumbreras, J.; Papaloukas, C.; Karakitsios, S.

    2010-10-01

    In this study, we used and compared three different statistical clustering methods: an hierarchical, a non-hierarchical (K-means) and an artificial neural network technique (self-organizing maps (SOM)). These classification methods were applied to a 4-year dataset of 5 days kinematic back trajectories of air masses arriving in Athens, Greece at 12.00 UTC, in three different heights, above the ground. The atmospheric back trajectories were simulated with the HYSPLIT Vesion 4.7 model of National Oceanic and Atmospheric Administration (NOAA). The meteorological data used for the computation of trajectories were obtained from NOAA reanalysis database. A comparison of the three statistical clustering methods through statistical indices was attempted. It was found that all three statistical methods seem to depend to the arrival height of the trajectories, but the degree of dependence differs substantially. Hierarchical clustering showed the highest level of dependence for fast-moving trajectories to the arrival height, followed by SOM. K-means was found to be the least depended clustering technique on the arrival height. The air quality management applications of these results in relation to PM10 concentrations recorded in Athens, Greece, were also discussed. Differences of PM10 concentrations, during certain clusters, were found statistically different (at 95% confidence level) indicating that these clusters appear to be associated with long-range transportation of particulates. This study can improve the interpretation of modelled atmospheric trajectories, leading to a more reliable analysis of synoptic weather circulation patterns and their impacts on urban air quality.

  19. Soccer ball lift coefficients via trajectory analysis

    NASA Astrophysics Data System (ADS)

    Goff, John Eric; Carré, Matt J.

    2010-07-01

    We performed experiments in which a soccer ball was launched from a machine while two high-speed cameras recorded portions of the trajectory. Using the trajectory data and published drag coefficients, we extracted lift coefficients for a soccer ball. We determined lift coefficients for a wide range of spin parameters, including several spin parameters that have not been obtained by today's wind tunnels. Our trajectory analysis technique is not only a valuable tool for professional sports scientists, it is also accessible to students with a background in undergraduate-level classical mechanics.

  20. Helicopter trajectory planning using optimal control theory

    NASA Technical Reports Server (NTRS)

    Menon, P. K. A.; Cheng, V. H. L.; Kim, E.

    1988-01-01

    A methodology for optimal trajectory planning, useful in the nap-of-the-earth guidance of helicopters, is presented. This approach uses an adjoint-control transformation along with a one-dimensional search scheme for generating the optimal trajectories. In addition to being useful for helicopter nap-of-the-earth guidance, the trajectory planning solution is of interest in several other contexts, such as robotic vehicle guidance and terrain-following guidance for cruise missiles and aircraft. A distinguishing feature of the present research is that the terrain constraint and the threat envelopes are incorporated in the equations of motion. Second-order necessary conditions are examined.

  1. Mars Ascent Propulsion Trades with Trajectory Analysis

    SciTech Connect

    Whitehead, J

    2004-04-22

    Optimized trajectories to a 500 km circular orbit are calculated for vehicles having a 100 kg Mars launch mass. Staging trades, thrust optimization, and the importance of vehicle shape for drag are all taken into consideration. The high acceleration of solid rockets requires a steep trajectory for drag avoidance, followed by a relatively large circularization burn, appropriate for a second stage. Liquid thrust reduces drag, resulting in less steep trajectories which have small circularization burns. Liquid propulsion requires less total {Delta}v, and offers options for multiple stages or just one. Graphs of payload mass versus stage propellant fractions are compared for liquid and solid propulsion.

  2. An Examination of "The Martian" Trajectory

    NASA Technical Reports Server (NTRS)

    Burke, Laura

    2015-01-01

    This analysis was performed to support a request to examine the trajectory of the Hermes vehicle in the novel "The Martian" by Andy Weir. Weir developed his own tool to perform the analysis necessary to provide proper trajectory information for the novel. The Hermes vehicle is the interplanetary spacecraft that shuttles the crew to and from Mars. It is notionally a Nuclear powered vehicle utilizing VASIMR engines for propulsion. The intent of this analysis was the determine whether the trajectory as it was outlined in the novel is consistent with the rules of orbital mechanics.

  3. Ascent trajectory dispersion analysis for WTR heads-up space shuttle trajectory

    NASA Technical Reports Server (NTRS)

    1986-01-01

    The results of a Space Transportation System ascent trajectory dispersion analysis are discussed. The purpose is to provide critical trajectory parameter values for assessing the Space Shuttle in a heads-up configuration launched from the Western Test Range (STR). This analysis was conducted using a trajectory profile based on a launch from the WTR in December. The analysis consisted of the following steps: (1) nominal trajectories were simulated under the conditions as specified by baseline reference mission guidelines; (2) dispersion trajectories were simulated using predetermined parametric variations; (3) requirements for a system-related composite trajectory were determined by a root-sum-square (RSS) analysis of the positive deviations between values of the aerodynamic heating indicator (AHI) generated by the dispersion and nominal trajectories; (4) using the RSS assessment as a guideline, the system related composite trajectory was simulated by combinations of dispersion parameters which represented major contributors; (5) an assessment of environmental perturbations via a RSS analysis was made by the combination of plus or minus 2 sigma atmospheric density variation and 95% directional design wind dispersions; (6) maximum aerodynamic heating trajectories were simulated by variation of dispersion parameters which would emulate the summation of the system-related RSS and environmental RSS values of AHI. The maximum aerodynamic heating trajectories were simulated consistent with the directional winds used in the environmental analysis.

  4. DUS II SOIL GAS SAMPLING AND AIR INJECTION TEST RESULTS

    SciTech Connect

    Noonkester, J.; Jackson, D.; Jones, W.; Hyde, W.; Kohn, J.; Walker, R.

    2012-09-20

    Soil vapor extraction (SVE) and air injection well testing was performed at the Dynamic Underground Stripping (DUS) site located near the M-Area Settling Basin (referred to as DUS II in this report). The objective of this testing was to determine the effectiveness of continued operation of these systems. Steam injection ended on September 19, 2009 and since this time the extraction operations have utilized residual heat that is present in the subsurface. The well testing campaign began on June 5, 2012 and was completed on June 25, 2012. Thirty-two (32) SVE wells were purged for 24 hours or longer using the active soil vapor extraction (ASVE) system at the DUS II site. During each test five or more soil gas samples were collected from each well and analyzed for target volatile organic compounds (VOCs). The DUS II site is divided into four parcels (see Figure 1) and soil gas sample results show the majority of residual VOC contamination remains in Parcel 1 with lesser amounts in the other three parcels. Several VOCs, including tetrachloroethylene (PCE) and trichloroethylene (TCE), were detected. PCE was the major VOC with lesser amounts of TCE. Most soil gas concentrations of PCE ranged from 0 to 60 ppmv with one well (VEW-22A) as high as 200 ppmv. Air sparging (AS) generally involves the injection of air into the aquifer through either vertical or horizontal wells. AS is coupled with SVE systems when contaminant recovery is necessary. While traditional air sparging (AS) is not a primary component of the DUS process, following the cessation of steam injection, eight (8) of the sixty-three (63) steam injection wells were used to inject air. These wells were previously used for hydrous pyrolysis oxidation (HPO) as part of the DUS process. Air sparging is different from the HPO operations in that the air was injected at a higher rate (20 to 50 scfm) versus HPO (1 to 2 scfm). . At the DUS II site the air injection wells were tested to determine if air sparging affected

  5. Analysis of flight trajectories of a ramjet-powered vehicle

    NASA Astrophysics Data System (ADS)

    Fomin, V. M.; Aulchenko, S. M.; Zvegintsev, V. I.; Ustinov, L. A.

    2014-11-01

    Based on numerical simulations of flight trajectories with ramjet-powered flying vehicles, it is found that all possible flight trajectories can be classified into three groups: ballistic trajectories, trajectories with a horizontal segment, and skipping trajectories. Trajectories of each group can be optimized, for instance, to ensure the maximum flight range under given initial conditions and constraints. Examples of optimal trajectories for a given amount of available fuel are presented as functions of the initial slope of the trajectory, angle of attack of the vehicle, instants of engine actuation, and engine operation time.

  6. Air pollution modifies floral scent trails

    NASA Astrophysics Data System (ADS)

    McFrederick, Quinn S.; Kathilankal, James C.; Fuentes, Jose D.

    Floral hydrocarbons provide essential signals to attract pollinators. As soon as they are emitted to the atmosphere, however, hydrocarbons are destroyed by chemical reactions involving pollutants such as ozone. It is therefore likely that increased air pollution interferes with pollinator attracting hydrocarbon signals. To test this hypothesis, a Lagrangian diffusion model was used to determine the position of air parcels away from hydrocarbon sources and to estimate the rate of chemical destruction of hydrocarbons as air parcels moved across the landscape. The hydrocarbon compounds linalool, β-myrcene, and β-ocimene were chosen because they are known to be common scents released from flowers. The suppressed ambient abundances of volatile organic compounds were determined in response to increased regional levels of ozone, hydroxyl, and nitrate radicals. The results indicate that the documented increases in air pollution concentrations, from pre-industrial to present times, can lead to reductions in volatile compound concentrations insects detect as they pollinate flowers. For highly reactive volatiles the maximum downwind distance from the source at which pollinators can detect the scents may have changed from kilometers during pre-industrial times to <200 m during the more polluted conditions of present times. The increased destruction of floral signals in polluted air masses may have important implications for both pollinators and signaling plants. When patches of flowers are further apart than the visual range of pollinators, such as in fragmented landscapes, the loss of scent signals may mean that pollinators spend more time searching for patches and less time foraging. This decrease in pollinator foraging efficiency will simultaneously decrease the pollinator's reproductive output and the amount of pollen flow in flowering plants.

  7. A trajectory modeling investigation of the biomass burning-tropical ozone relationship

    NASA Technical Reports Server (NTRS)

    Pickering, Kenneth E.; Thompson, Anne M.; Mcnamara, Donna P.; Schoeberl, Mark R.; Lait, Leslie R.; Newman, Paul A.; Justice, Christopher O.; Kendall, Jacqueline D.

    1994-01-01

    The hypothesis that tropical total O3 maxima seen by the TOMS satellite derive from African biomass burning has been tested using isentropic trajectory analyses with global meteorological data fields. Two case studies from the 1989 biomass burning season demonstrate that a large fraction of the air arriving at the location of TOMS O3 maxima passed over regions of intense burning. Other trajectories initiated at a series of points over Africa and the Atlantic suggest flight strategies for field studies to be conducted in September 1992.

  8. Heuristics for connectivity-based brain parcellation of SMA/pre-SMA through force-directed graph layout.

    PubMed

    Crippa, Alessandro; Cerliani, Leonardo; Nanetti, Luca; Roerdink, Jos B T M

    2011-02-01

    We propose the use of force-directed graph layout as an explorative tool for connectivity-based brain parcellation studies. The method can be used as a heuristic to find the number of clusters intrinsically present in the data (if any) and to investigate their organisation. It provides an intuitive representation of the structure of the data and facilitates interactive exploration of properties of single seed voxels as well as relations among (groups of) voxels. We validate the method on synthetic data sets and we investigate the changes in connectivity in the supplementary motor cortex, a brain region whose parcellation has been previously investigated via connectivity studies. This region is supposed to present two easily distinguishable connectivity patterns, putatively denoted by SMA (supplementary motor area) and pre-SMA. Our method provides insights with respect to the connectivity patterns of the premotor cortex. These present a substantial variation among subjects, and their subdivision into two well-separated clusters is not always straightforward.

  9. Measurement of aerosol particles, gases and flux radiation in the Pico de Orizaba National Park, and its relationship to air pollution transport

    NASA Astrophysics Data System (ADS)

    Márquez, C.; Castro, T.; Muhlia, A.; Moya, M.; Martínez-Arroyo, A.; Báez, A.

    Continuous atmospheric measurements were carried out at the Pico de Orizaba National Park (PONP), Mexico, in order to evaluate the characteristics and sources of air quality. This action allowed one to identify specific threats for the effective protection of natural resources and biodiversity. Results show the presence of particles and polluted gases transported by winds from the urban zones nearby (cities of Mexico, Puebla and Tlaxcala), as well as their measurable influence on the optical properties of the park environment. Nitrogen dioxide, carbon monoxide and sulfur dioxide show a daily pattern suggesting an influence of pollution generated by anthropogenic processes. Average concentration of SO 2 was higher than recorded at the southern part of Mexico City. Ozone concentrations ranging from 0.035 to 0.06 ppm suggest residual or background ozone character. Back trajectory analysis of air parcels arriving at the site confirm pollution caused by biomass burning and mass transport from urban zones. The SO 42-/TC ratio exhibited values (0.88±0.33) similar to urban areas. Ratios BC/TC and OC/BC for PONP are similar to those reported as influenced by burning emissions of fossil fuels. Typical rural aerosols were also found at the site, and sulfate and ammonium concentrations were correlated. The most predominating mode in surface particles size distribution was at 0.32 μm with no significant presence of coarse particles. Total carbon (OC+BC) content of fine particle mass (PM less than 1 μm) comprised, on average, 75%. Optical properties retrieved from photometric data show intermittent influence from urban pollution. Time periods with low absorbing particles, great visibility and abundance of small particles alternating with short times with bigger particles and high turbidity indicated by the optical depth.

  10. Air Research

    EPA Pesticide Factsheets

    EPA's air research provides the critical science to develop and implement outdoor air regulations under the Clean Air Act and puts new tools and information in the hands of air quality managers and regulators to protect the air we breathe.

  11. Algorithm for fuel conservative horizontal capture trajectories

    NASA Technical Reports Server (NTRS)

    Neuman, F.; Erzberger, H.

    1981-01-01

    A real time algorithm for computing constant altitude fuel-conservative approach trajectories for aircraft is described. The characteristics of the trajectory computed were chosen to approximate the extremal trajectories obtained from the optimal control solution to the problem and showed a fuel difference of only 0.5 to 2 percent for the real time algorithm in favor of the extremals. The trajectories may start at any initial position, heading, and speed and end at any other final position, heading, and speed. They consist of straight lines and a series of circular arcs of varying radius to approximate constant bank-angle decelerating turns. Throttle control is maximum thrust, nominal thrust, or zero thrust. Bank-angle control is either zero or aproximately 30 deg.

  12. Trajectory of the index finger during grasping.

    PubMed

    Friedman, Jason; Flash, Tamar

    2009-07-01

    The trajectory of the index finger during grasping movements was compared to the trajectories predicted by three optimization-based models. The three models consisted of minimizing the integral of the weighted squared joint derivatives along the path (inertia-like cost), minimizing torque change, and minimizing angular jerk. Of the three models, it was observed that the path of the fingertip and the joint trajectories, were best described by the minimum angular jerk model. This model, which does not take into account the dynamics of the finger, performed equally well when the inertia of the finger was altered by adding a 20 g weight to the medial phalange. Thus, for the finger, it appears that trajectories are planned based primarily on kinematic considerations at a joint level.

  13. Trajectories of Alcohol Consumption Following Liver Transplantation

    PubMed Central

    DiMartini, Andrea; Dew, Mary Amanda; Day, Nancy; Fitzgerald, Mary Grace; Jones, Bobby L.; deVera, Michael; Fontes, Paulo

    2010-01-01

    Any use of alcohol in the years following liver transplantation (LTX) approaches 50% of patients transplanted for alcoholic liver disease (ALD). We collected detailed prospective data on alcohol consumption following LTX for ALD to investigate ongoing patterns of use. Using trajectory modeling we identified four distinct alcohol use trajectories. One group had minimal use over time. Two other groups developed early onset moderate to heavy consumption and one group developed late onset moderate use. These trajectories demonstrate that alcohol use varies based on timing of onset, quantity, and duration. Using discriminant function analysis, we examine characteristics of recipient’s pre-LTX alcohol histories and early post-LTX psychological stressors to identify the profile of those at risk for these specific trajectories. We discuss the relevance of these findings to clinical care and preliminarily to outcomes. PMID:20726963

  14. Goddard trajectory determination subsystem: Mathematical specifications

    NASA Technical Reports Server (NTRS)

    Wagner, W. E. (Editor); Velez, C. E. (Editor)

    1972-01-01

    The mathematical specifications of the Goddard trajectory determination subsystem of the flight dynamics system are presented. These specifications include the mathematical description of the coordinate systems, dynamic and measurement model, numerical integration techniques, and statistical estimation concepts.

  15. Algorithm for fixed-range optimal trajectories

    NASA Technical Reports Server (NTRS)

    Lee, H. Q.; Erzberger, H.

    1980-01-01

    An algorithm for synthesizing optimal aircraft trajectories for specified range was developed and implemented in a computer program written in FORTRAN IV. The algorithm, its computer implementation, and a set of example optimum trajectories for the Boeing 727-100 aircraft are described. The algorithm optimizes trajectories with respect to a cost function that is the weighted sum of fuel cost and time cost. The optimum trajectory consists at most of a three segments: climb, cruise, and descent. The climb and descent profiles are generated by integrating a simplified set of kinematic and dynamic equations wherein the total energy of the aircraft is the independent or time like variable. At each energy level the optimum airspeeds and thrust settings are obtained as the values that minimize the variational Hamiltonian. Although the emphasis is on an off-line, open-loop computation, eventually the most important application will be in an on-board flight management system.

  16. Numerical Calculation of Model Rocket Trajectories.

    ERIC Educational Resources Information Center

    Keeports, David

    1990-01-01

    Discussed is the use of model rocketry to teach the principles of Newtonian mechanics. Included are forces involved; calculations for vertical launches; two-dimensional trajectories; and variations in mass, drag, and launch angle. (CW)

  17. Trajectory tracking control for underactuated stratospheric airship

    NASA Astrophysics Data System (ADS)

    Zheng, Zewei; Huo, Wei; Wu, Zhe

    2012-10-01

    Stratospheric airship is a new kind of aerospace system which has attracted worldwide developing interests for its broad application prospects. Based on the trajectory linearization control (TLC) theory, a novel trajectory tracking control method for an underactuated stratospheric airship is presented in this paper. Firstly, the TLC theory is described sketchily, and the dynamic model of the stratospheric airship is introduced with kinematics and dynamics equations. Then, the trajectory tracking control strategy is deduced in detail. The designed control system possesses a cascaded structure which consists of desired attitude calculation, position control loop and attitude control loop. Two sub-loops are designed for the position and attitude control loops, respectively, including the kinematics control loop and dynamics control loop. Stability analysis shows that the controlled closed-loop system is exponentially stable. Finally, simulation results for the stratospheric airship to track typical trajectories are illustrated to verify effectiveness of the proposed approach.

  18. The Trajectories of Saccadic Eye Movements.

    ERIC Educational Resources Information Center

    Bahill, A. Terry; Stark, Lawrence

    1979-01-01

    Investigates the trajectories of saccadic eye movements, the control signals of the eye, and nature of the mechanisms that generate them, using the techniques of bioengineering in collecting the data. (GA)

  19. A human brain atlas derived via n-cut parcellation of resting-state and task-based fMRI data.

    PubMed

    James, George Andrew; Hazaroglu, Onder; Bush, Keith A

    2016-02-01

    The growth of functional MRI has led to development of human brain atlases derived by parcellating resting-state connectivity patterns into functionally independent regions of interest (ROIs). All functional atlases to date have been derived from resting-state fMRI data. But given that functional connectivity between regions varies with task, we hypothesized that an atlas incorporating both resting-state and task-based fMRI data would produce an atlas with finer characterization of task-relevant regions than an atlas derived from resting-state alone. To test this hypothesis, we derived parcellation atlases from twenty-nine healthy adult participants enrolled in the Cognitive Connectome project, an initiative to improve functional MRI's translation into clinical decision-making by mapping normative variance in brain-behavior relationships. Participants underwent resting-state and task-based fMRI spanning nine cognitive domains: motor, visuospatial, attention, language, memory, affective processing, decision-making, working memory, and executive function. Spatially constrained n-cut parcellation derived brain atlases using (1) all participants' functional data (Task) or (2) a single resting-state scan (Rest). An atlas was also derived from random parcellation for comparison purposes (Random). Two methods were compared: (1) a parcellation applied to the group's mean edge weights (mean), and (2) a two-stage approach with parcellation of individual edge weights followed by parcellation of mean binarized edges (two-stage). The resulting Task and Rest atlases had significantly greater similarity with each other (mean Jaccard indices JI=0.72-0.85) than with the Random atlases (JI=0.59-0.63; all p<0.001 after Bonferroni correction). Task and Rest atlas similarity was greatest for the two-stage method (JI=0.85), which has been shown as more robust than the mean method; these atlases also better reproduced voxelwise seed maps of the left dorsolateral prefrontal cortex during

  20. Trajectory Browser: An Online Tool for Interplanetary Trajectory Analysis and Visualization

    NASA Technical Reports Server (NTRS)

    Foster, Cyrus James

    2013-01-01

    The trajectory browser is a web-based tool developed at the NASA Ames Research Center for finding preliminary trajectories to planetary bodies and for providing relevant launch date, time-of-flight and (Delta)V requirements. The site hosts a database of transfer trajectories from Earth to planets and small-bodies for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and (Delta)V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies.

  1. Retrievals of Vertical Air Motion from the HIAPER Cloud Radar during CSET

    NASA Astrophysics Data System (ADS)

    Schwartz, M. C.; Ghate, V. P.; Vivekanandan, J.; Tsai, P.; Ellis, S. M.

    2015-12-01

    Marine boundary layer cumulus and stratocumulus clouds are significant factors in the Earth's climate system and hence need to be accurately represented in Global Climate Model (GCM) simulations. One feature germane to these clouds, and where GCMs encounter difficulty, is the transition from stratocumulus- to cumulus-capped marine boundary layers (MBLs). This transition is climatologically important due to the large decreases in cloud cover and to the significant changes in boundary layer structure that accompany it. An important component of understanding this transition is the ability to characterize the evolution of the vertical velocity structure of the MBL. During the Cloud System Evolution in the Trades (CSET) field program, held in July and August 2015, the NSF/NCAR Gulfstream-V High-performance Instrumented Airborne Platform for Environmental Research (GV HIAPER) aircraft made several transects from California to Hawaii to characterize the stratocumulus to Cumulus transition. The GV-HIAPER carried several remote sensing and in situ instruments for observing aerosol, cloud, precipitation, radiation and meteorological properties. Within selected air masses, flight legs were conducted above, inside, and below the cloud layers during aircraft transits from California to Hawaii. The same air masses (as determined by parcel trajectory analysis) were resampled on the return flight to California a day later. Of particular importance to studying MBL clouds are the HIAPER Cloud Radar (HCR) and the High Spectral Resolution Lidar (HSRL), which provided mapping of aerosol, cloud, and precipitation structures. From the W-band HCR, full radar Doppler spectra were calculated at 0.5 sec resolution. The 532 nm HSRL was fully calibrated and used to retrieve the aerosol extinction profiles. We have first combined the data collected by the HCR and the HSRL to create a hydrometeor mask, which will be used to characterize changes in the cloud structure. The Doppler spectrum from

  2. Trajectory options for the DART mission

    NASA Astrophysics Data System (ADS)

    Atchison, Justin A.; Ozimek, Martin T.; Kantsiper, Brian L.; Cheng, Andrew F.

    2016-06-01

    This study presents interplanetary trajectory options for the Double Asteroid Redirection Test (DART) spacecraft to reach the near Earth object, Didymos binary system, during its 2022 Earth conjunction. DART represents a component of a joint NASA-ESA mission to study near Earth object kinetic impact deflection. The DART trajectory must satisfy mission objectives for arrival timing, geometry, and lighting while minimizing launch vehicle and spacecraft propellant requirements. Chemical propulsion trajectories are feasible from two candidate launch windows in late 2020 and 2021. The 2020 trajectories are highly perturbed by Earth's orbit, requiring post-launch deep space maneuvers to retarget the Didymos system. Within these windows, opportunities exist for flybys of additional near Earth objects: Orpheus in 2021 or 2007 YJ in 2022. A second impact attempt, in the event that the first impact is unsuccessful, can be added at the expense of a shorter launch window and increased (∼3x) spacecraft ΔV . However, the second impact arrival geometry has poor lighting, high Earth ranges, and would require additional degrees of freedom for solar panel and/or antenna gimbals. A low-thrust spacecraft configuration increases the trajectory flexibility. A solar electric propulsion spacecraft could be affordably launched as a secondary spacecraft in an Earth orbit and spiral out to target the requisite interplanetary departure condition. A sample solar electric trajectory was constructed from an Earth geostationary transfer using a representative 1.5 kW thruster. The trajectory requires 9 months to depart Earth's sphere of influence, after which its interplanetary trajectory includes a flyby of Orpheus and a second Didymos impact attempt. The solar electric spacecraft implementation would impose additional bus design constraints, including large solar arrays that could pose challenges for terminal guidance. On the basis of this study, there are many feasible options for DART to

  3. Filtering Drifter Trajectories Sampled at Submesoscale Resolution

    DTIC Science & Technology

    2015-05-11

    40, NO. 3, JULY 2015 497 Filtering Drifter Trajectories Sampled at Submesoscale Resolution Max Yaremchuk and Emanuel F. Coelho Abstract—In this paper...accel- erations while keeping the difference between the filtered and ob- served trajectories within the error bars of the positioning noise...Mexico in 2012. Index Terms—Computers and information processing/data pro- cessing,mathematics/ filtering algorithms, optimization, smoothing methods

  4. Optimizing Simulated Trajectories Of Rigid Bodies

    NASA Technical Reports Server (NTRS)

    Brauer, Garry L.; Olson, David W.; Stevenson, Robert

    1989-01-01

    6D POST is general-purpose, six-degree-of-freedom computer program for optimization of simulated trajectories of rigid bodies. Direct extension of three-degree-of-freedom POST program. 6D POST program models trajectory of powered or unpowered vehicle operating at or near rotating planet. Used to solve variety of performance, guidance, and flight-control problems for atmospheric and orbital vehicles. Written in FORTRAN 77 and FORTRAN V.

  5. Systematic Disturbance Of Optimal Rotational Trajectory

    NASA Technical Reports Server (NTRS)

    Grunwald, Arthur J.; Kaiser, Mary K.

    1992-01-01

    Algorithm introduces systematic disturbance into otherwise optimal rotation of body from prescribed initial to prescribed final orientation. Disturbance introduced as deviation of actual axis of rotation from optimal one, like wobble of top. Algorithm effects rotational transformations and solves differential equations necessary to compute disturbed trajectory. Devised for use with motion-control program and three-dimensional computer-graphical display to study ability of observers to distinguish between optimal and suboptimal rotational trajectories.

  6. Machine Learning for Biological Trajectory Classification Applications

    NASA Technical Reports Server (NTRS)

    Sbalzarini, Ivo F.; Theriot, Julie; Koumoutsakos, Petros

    2002-01-01

    Machine-learning techniques, including clustering algorithms, support vector machines and hidden Markov models, are applied to the task of classifying trajectories of moving keratocyte cells. The different algorithms axe compared to each other as well as to expert and non-expert test persons, using concepts from signal-detection theory. The algorithms performed very well as compared to humans, suggesting a robust tool for trajectory classification in biological applications.

  7. Mars interplanetary trajectory design via Lagrangian points

    NASA Astrophysics Data System (ADS)

    Eapen, Roshan Thomas; Sharma, Ram Krishan

    2014-09-01

    With the increase in complexities of interplanetary missions, the main focus has shifted to reducing the total delta-V for the entire mission and hence increasing the payload capacity of the spacecraft. This paper develops a trajectory to Mars using the Lagrangian points of the Sun-Earth system and the Sun-Mars system. The whole trajectory can be broadly divided into three stages: (1) Trajectory from a near-Earth circular parking orbit to a halo orbit around Sun-Earth Lagrangian point L2. (2) Trajectory from Sun-Earth L2 halo orbit to Sun-Mars L1 halo orbit. (3) Sun-Mars L1 halo orbit to a circular orbit around Mars. The stable and unstable manifolds of the halo orbits are used for halo orbit insertion. The intermediate transfer arcs are designed using two-body Lambert's problem. The total delta-V for the whole trajectory is computed and found to be lesser than that for the conventional trajectories. For a 480 km Earth parking orbit, the total delta-V is found to be 4.6203 km/s. Another advantage in the present approach is that delta-V does not depend upon the synodic period of Earth with respect to Mars.

  8. A method for balloon trajectory control

    NASA Astrophysics Data System (ADS)

    Aaron, K. M.; Heun, M. K.; Nock, K. T.

    A balloon trajectory control system is discussed that is under development for use on NASA's Ultra Long Duration Balloon Project. The trajectory control system exploits the natural wind field variation with altitude to generate passive lateral control forces on a balloon using a tether-deployed aerodynamic surface below the balloon. A lifting device, such as a wing on end, is suspended on a tether well beneath the balloon to take advantage of this variation in wind velocity with altitude. The wing generates a horizontal lift force that can be directed over a wide range of angles. This force, transmitted to the balloon by a tether, alters the balloon's path providing a bias velocity of a few meters per second to the balloon drift rate. The trajectory control system enables the balloon to avoid hazards, reach targets, steer around avoidance countries and select convenient landing zones. No longer will balloons be totally at the mercy of the winds. Tests in April 1999 of a dynamically-scaled model of the trajectory control system were carried out by Global Aerospace Corporation in ground level winds up to 15 m/s. The size of the scale model was designed to simulate the behavior of the full scale trajectory control system operating at 20 km altitude. The model confirmed many aspects of trajectory control system performance and the results will be incorporated into future development.

  9. Optimizing interplanetary trajectories with deep space maneuvers

    NASA Astrophysics Data System (ADS)

    Navagh, John

    1993-09-01

    Analysis of interplanetary trajectories is a crucial area for both manned and unmanned missions of the Space Exploration Initiative. A deep space maneuver (DSM) can improve a trajectory in much the same way as a planetary swingby. However, instead of using a gravitational field to alter the trajectory, the on-board propulsion system of the spacecraft is used when the vehicle is not near a planet. The purpose is to develop an algorithm to determine where and when to use deep space maneuvers to reduce the cost of a trajectory. The approach taken to solve this problem uses primer vector theory in combination with a non-linear optimizing program to minimize Delta(V). A set of necessary conditions on the primer vector is shown to indicate whether a deep space maneuver will be beneficial. Deep space maneuvers are applied to a round trip mission to Mars to determine their effect on the launch opportunities. Other studies which were performed include cycler trajectories and Mars mission abort scenarios. It was found that the software developed was able to locate quickly DSM's which lower the total Delta(V) on these trajectories.

  10. The "medio-latero-superior trajectory technique": an alternative cortical trajectory for pedicle fixation.

    PubMed

    Mobbs, Ralph J

    2013-02-01

    An alternative pedicle trajectory for use at the superior end of a construct to limit dissection of the mobile superior facet joint and reduce incision length and muscle dissection, thus minimizing approach-related trauma during pedicle fixation, is reported. The medio-latero-superior trajectory technique involves a starting point on the medial aspect of the pars and angulation of the pedicle screw in a mediolateral and caudocranial direction. This approach takes advantage of a predominantly cortical trajectory to assist with bone fixation. Drawbacks of this new screw trajectory are discussed along with its potential benefits.

  11. Superdiffusive trajectories in Brownian motion.

    PubMed

    Duplat, Jérôme; Kheifets, Simon; Li, Tongcang; Raizen, Mark G; Villermaux, Emmanuel

    2013-02-01

    The Brownian motion of a microscopic particle in a fluid is one of the cornerstones of statistical physics and the paradigm of a random process. One of the most powerful tools to quantify it was provided by Langevin, who explicitly accounted for a short-time correlated "thermal" force. The Langevin picture predicts ballistic motion, ~t(2) at short-time scales, and diffusive motion ~t at long-time scales, where x is the displacement of the particle during time t, and the average is taken over the thermal distribution of initial conditions. The Langevin equation also predicts a superdiffusive regime, where ~t(3), under the condition that the initial velocity is fixed rather than distributed thermally. We analyze the motion of an optically trapped particle in air and indeed find t(3) dispersion. This observation is a direct proof of the existence of the random, rapidly varying force imagined by Langevin.

  12. Automatic acquisition of motion trajectories: tracking hockey players

    NASA Astrophysics Data System (ADS)

    Okuma, Kenji; Little, James J.; Lowe, David

    2003-12-01

    Computer systems that have the capability of analyzing complex and dynamic scenes play an essential role in video annotation. Scenes can be complex in such a way that there are many cluttered objects with different colors, shapes and sizes, and can be dynamic with multiple interacting moving objects and a constantly changing background. In reality, there are many scenes that are complex, dynamic, and challenging enough for computers to describe. These scenes include games of sports, air traffic, car traffic, street intersections, and cloud transformations. Our research is about the challenge of inventing a descriptive computer system that analyzes scenes of hockey games where multiple moving players interact with each other on a constantly moving background due to camera motions. Ultimately, such a computer system should be able to acquire reliable data by extracting the players" motion as their trajectories, querying them by analyzing the descriptive information of data, and predict the motions of some hockey players based on the result of the query. Among these three major aspects of the system, we primarily focus on visual information of the scenes, that is, how to automatically acquire motion trajectories of hockey players from video. More accurately, we automatically analyze the hockey scenes by estimating parameters (i.e., pan, tilt, and zoom) of the broadcast cameras, tracking hockey players in those scenes, and constructing a visual description of the data by displaying trajectories of those players. Many technical problems in vision such as fast and unpredictable players' motions and rapid camera motions make our challenge worth tackling. To the best of our knowledge, there have not been any automatic video annotation systems for hockey developed in the past. Although there are many obstacles to overcome, our efforts and accomplishments would hopefully establish the infrastructure of the automatic hockey annotation system and become a milestone for

  13. Current trajectory options for a comet nucleus sample return mission

    NASA Astrophysics Data System (ADS)

    Sauer, Carl G., Jr.

    1992-08-01

    A summary of the current trajectory options available for the ESA comet nucleus sample return mission, Rosetta, is presented. These options include direct trajectories, delta-V-EGA trajectories using a Titan IV/Centaur launch vehicle with upgraded solid rocket motors, a trajectory involving a gravity assist of the earth (VEGA) prior to comet rendezvous, and one involving an additional gravity assist of the earth (VEEGA). Other propulsion options proposed and discussed are solar electric propulsion/ballistic trajectory modes and nuclear electric propulsion trajectory modes. Tables of performance data for each of these trajectory options are given.

  14. Method and Apparatus for Generating Flight-Optimizing Trajectories

    NASA Technical Reports Server (NTRS)

    Ballin, Mark G. (Inventor); Wing, David J. (Inventor)

    2015-01-01

    An apparatus for generating flight-optimizing trajectories for a first aircraft includes a receiver capable of receiving second trajectory information associated with at least one second aircraft. The apparatus also includes a traffic aware planner (TAP) module operably connected to the receiver to receive the second trajectory information. The apparatus also includes at least one internal input device on board the first aircraft to receive first trajectory information associated with the first aircraft and a TAP application capable of calculating an optimal trajectory for the first aircraft based at least on the first trajectory information and the second trajectory information. The optimal trajectory at least avoids conflicts between the first trajectory information and the second trajectory information.

  15. Automated Design of Noise-Minimal, Safe Rotorcraft Trajectories

    NASA Technical Reports Server (NTRS)

    Morris, Robert A.; Venable, K. Brent; Lindsay, James

    2012-01-01

    NASA and the international community are investing in the development of a commercial transportation infrastructure that includes the increased use of rotorcraft, specifically helicopters and aircraft such as a 40-passenger civil tilt rotors. Rotorcraft have a number of advantages over fixed wing aircraft, primarily in not requiring direct access to the primary fixed wing runways. As such they can operate at an airport without directly interfering with major air carrier and commuter aircraft operations. However, there is significant concern over the impact of noise on the communities surrounding the transportation facilities. In this paper we propose to address the rotorcraft noise problem by exploiting powerful search techniques coming from artificial intelligence, coupled with simulation and field tests, to design trajectories that are expected to improve on the amount of ground noise generated. This paper investigates the use of simulation based on predictive physical models to facilitate the search for low-noise trajectories using a class of automated search algorithms called local search. A novel feature of this approach is the ability to incorporate constraints into the problem formulation that addresses passenger safety and comfort.

  16. An examination of slo-pitch pitching trajectories.

    PubMed

    Wu, Tom; Gervais, Pierre

    2008-01-01

    Many slo-pitch coaches and players believe that generating spin on a ball can affect its trajectory. The influence of air resistance on a ball that is thrown at a moderate speed and spin is unclear. The aim of this study was to examine the influence of spin on the ball's trajectory in slo-pitch pitching using both experimental results and ball flight simulations. Fourteen pitchers participated in the study, each of whom threw five backspin and topspin pitches each. Data were collected using standard three-dimensional videography. The horizontal velocity, vertical velocity, angular velocity, release height, and horizontal displacement of the backspin pitches were significantly higher than those of the topspin pitches. The ball flight simulations were developed to examine the influence of the ball spin, and it was concluded that the spin of the ball had a significant effect on the ball's vertical and horizontal displacements. Furthermore, our results suggest that a backspin pitch that reaches the maximum height allowable and lands in the front edge of the strike zone has the steepest slope. The present results add to our understanding of projectile motion and aerodynamics.

  17. Using Tax Parcels to Select a Location-Based Sample: An Illustration that Examines Residents' Awareness of Sex Offenders in Neighborhoods

    ERIC Educational Resources Information Center

    Craun, Sarah W.; Freisthler, Bridget

    2008-01-01

    Social science research is increasingly considering place when examining social programs and policies with a spatial component. A specific research challenge involving spatial policies is how to select a sample of individuals based on their geographic locations. This article illustrates the use of geographic information systems, tax parcels, and…

  18. Adaptive Trajectory Prediction Algorithm for Climbing Flights

    NASA Technical Reports Server (NTRS)

    Schultz, Charles Alexander; Thipphavong, David P.; Erzberger, Heinz

    2012-01-01

    Aircraft climb trajectories are difficult to predict, and large errors in these predictions reduce the potential operational benefits of some advanced features for NextGen. The algorithm described in this paper improves climb trajectory prediction accuracy by adjusting trajectory predictions based on observed track data. It utilizes rate-of-climb and airspeed measurements derived from position data to dynamically adjust the aircraft weight modeled for trajectory predictions. In simulations with weight uncertainty, the algorithm is able to adapt to within 3 percent of the actual gross weight within two minutes of the initial adaptation. The root-mean-square of altitude errors for five-minute predictions was reduced by 73 percent. Conflict detection performance also improved, with a 15 percent reduction in missed alerts and a 10 percent reduction in false alerts. In a simulation with climb speed capture intent and weight uncertainty, the algorithm improved climb trajectory prediction accuracy by up to 30 percent and conflict detection performance, reducing missed and false alerts by up to 10 percent.

  19. EUROPA Multiple-Flyby Trajectory Design

    NASA Technical Reports Server (NTRS)

    Buffington, Brent; Campagnola, Stefano; Petropoulos, Anastassios

    2012-01-01

    As reinforced by the 2011 NRC Decadal Survey, Europa remains one of the most scientifically intriguing targets in planetary science due to its potential suitability for life. However, based on JEO cost estimates and current budgetary constraints, the Decadal Survey recommended-and later directed by NASA Headquarters-a more affordable pathway to Europa exploration be derived. In response, a flyby-only proof-of-concept trajectory has been developed to investigate Europa. The trajectory, enabled by employing a novel combination of new mission design techniques, successfully fulfills a set of Science Definition Team derived scientific objectives carried out by a notional payload including ice penetrating radar, topographic imaging, and short wavelength infrared observations, and ion neutral mass spectrometry in-situ measurements. The current baseline trajectory, referred to as 11-F5, consists of 34 Europa and 9 Ganymede flybys executed over the course of 2.4 years, reached a maximum inclination of 15 degrees, has a deterministic delta v of 157 m/s (post-PJR), and has a total ionizing dose of 2.06 Mrad (Si behind 100 mil Al, spherical shell). The 11-F5 trajectory and more generally speaking, flyby-only trajectories-exhibit a number of potential advantages over an Europa orbiter mission.

  20. Environmental Baseline Survey Report for the Title Transfer of Land Parcel ED-4 at the East Tennessee Technology Park, Oak Ridge, Tennessee

    SciTech Connect

    SAIC

    2008-05-01

    This environmental baseline survey (EBS) report documents the baseline environmental conditions of a land parcel referred to as 'ED-4' (ED-4) at the U. S. Department of Energy's (DOE's) East Tennessee Technology Park (ETTP). DOE is proposing to transfer the title of this land to the Heritage Center, LLC. Parcel ED-4 is a land parcel that consists of two noncontiguous areas comprising a total of approximately 18 acres located east of the ETTP. The western tract of ED-4 encompasses approximately 8.5 acres in the northeastern quadrant of the intersection of Boulevard Road and Highway 58. The eastern tract encompasses an area of approximately 9.5 acres in the northwestern quadrant of the intersection of Blair Road and Highway 58 (the Oak Ridge Turnpike). Aerial photographs and site maps from throughout the history of the ETTP, going back to its initial development in the 1940s as the Oak Ridge Gaseous Diffusion Plant (ORGDP), indicate that this area has been undeveloped woodland with the exception of three support facilities for workers constructing the ORGDP since federal acquisition in 1943. These three support facilities, which were located in the western tract of ED-4, included a recreation hall, the Town Hall Camp Operations Building, and the Property Warehouse. A railroad spur also formerly occupied a portion of Parcel ED-4. These former facilities only occupied approximately 5 percent of the total area of Parcel ED-4. This report provides supporting information for the transfer of this government-owned property at ETTP to a non-federal entity. This EBS is based upon the requirements of Sect. 120(h) of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA). In order to support a Clean Parcel Determination (CPD) in accordance with CERCLA Sect. 120(h)(4)(d), groundwater and sediment samples were collected within, and adjacent to, the Parcel ED-4 study area. The potential for DOE to make a CPD for ED-4 is further supported by a No

  1. The Evaluation of the Impact of New Technologies for Medium-Duty Parcel Delivery Trucks on Fuel Consumption

    SciTech Connect

    Wang, Lijuan; Duran, Adam; Kelly, Kenneth; Konan, Arnaud; Lammert, Michael; Prohaska, Robert

    2016-10-06

    In this paper, researchers at the National Renewable Energy Laboratory present the results of simulation studies to evaluate potential fuel savings as a result of improvements to vehicle rolling resistance, coefficient of drag, and vehicle weight as well as hybridization for four power trains for medium-duty parcel delivery vehicles. The vehicles will be modeled and simulated over 1,290 real-world driving trips to determine the fuel savings potential based on improvements to each technology and to identify best use cases for each platform. The results of impacts of new technologies on fuel saving will be presented, and the most favorable driving routes on which to adopt them will be explored.

  2. Socioeconomic inequalities in health trajectories in Switzerland: are trajectories diverging as people age?

    PubMed

    Cullati, Stéphane

    2015-06-01

    Do socioeconomic differences in health status increase as people age, reflecting cumulative advantage or disadvantage in health trajectories? Life course research hypothesises that cumulative advantage/disadvantage (CAD) is an important underlying social process that shape inequalities as people age. The objective of this study is to examine whether health trajectories are diverging as people age across socioeconomic positions (education, employment status and income). In a random sample of 3,665 respondents living in Switzerland (Swiss Household Panel 2004-2011), trajectories of self-rated health, body mass index, depression and medicated functioning were examined with multilevel regression models. The results showed that employment status and income were associated with diverging health trajectories among men; however, only a few associations supported the CAD hypothesis. Education was rarely associated with diverging health trajectories. In conclusion, little evidence was found to support the CAD model.

  3. Increased Water Diffusion in the Parcellated Cortical Regions from the Patients with Amnestic Mild Cognitive Impairment and Alzheimer's Disease.

    PubMed

    Lin, Sung-Han; Hsu, Wen-Chuin; Ng, Shu-Hang; Cheng, Jur-Shan; Khegai, Oleksandr; Huang, Chin-Chang; Chen, Yao-Liang; Chen, Yi-Chun; Wang, Jiun-Jie

    2016-01-01

    Background: The loss of cortical neuron environment integrity is the hallmark of neurodegeneration diseases such as Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). To reveal the microenvironment changes in cerebral cortex, the current study aimed to examine the changes of mean diffusivity (MD) in parcellated brain among AD, aMCI patients and normal controls (NC). Methods: Diffusion tensor imaging data with the whole brain coverage were acquired from 28 AD (aged 69.4 ± 8.2 year old), 41 aMCI patients (aged 68.2 ± 6.4 year old) and 40 NC subjects (aged 65.7 ± 6.4 year old). Subsequently, the MD values were parcellated according to the standard automatic anatomic labeling (AAL) template. Only the 90 regions located in the cerebral cortex were used in the final analysis. The mean values of MD from each brain region were extracted and compared among the participant groups. The integrity of the white matter tracts and gray matter atrophy was analyzed using the track-based spatial statistics and voxel-based morphometry approaches, respectively. Results: Significant differences of MD were noticed both in aMCI and AD patients, in terms of the affected regions and the amount of increase. The hippocampus, parahippocampal gyrus and cingulum were the most significantly affected regions in AD patients. From all the 90 cerebral cortex regions, significant increase of MD in the AD patients was found in 40 regions, compared to only one (fusiform gyrus on the right) in aMCI patients. In the disease affected regions, the MD from aMCI patients is in state between NC and AD patients. Conclusions: Increased MD in the specific regions of the brain shows the feasibility of MD as an indicator of the early stage cortical degeneration in aMCI and AD patients.

  4. Increased Water Diffusion in the Parcellated Cortical Regions from the Patients with Amnestic Mild Cognitive Impairment and Alzheimer's Disease

    PubMed Central

    Lin, Sung-Han; Hsu, Wen-Chuin; Ng, Shu-Hang; Cheng, Jur-Shan; Khegai, Oleksandr; Huang, Chin-Chang; Chen, Yao-Liang; Chen, Yi-Chun; Wang, Jiun-Jie

    2017-01-01

    Background: The loss of cortical neuron environment integrity is the hallmark of neurodegeneration diseases such as Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI). To reveal the microenvironment changes in cerebral cortex, the current study aimed to examine the changes of mean diffusivity (MD) in parcellated brain among AD, aMCI patients and normal controls (NC). Methods: Diffusion tensor imaging data with the whole brain coverage were acquired from 28 AD (aged 69.4 ± 8.2 year old), 41 aMCI patients (aged 68.2 ± 6.4 year old) and 40 NC subjects (aged 65.7 ± 6.4 year old). Subsequently, the MD values were parcellated according to the standard automatic anatomic labeling (AAL) template. Only the 90 regions located in the cerebral cortex were used in the final analysis. The mean values of MD from each brain region were extracted and compared among the participant groups. The integrity of the white matter tracts and gray matter atrophy was analyzed using the track-based spatial statistics and voxel-based morphometry approaches, respectively. Results: Significant differences of MD were noticed both in aMCI and AD patients, in terms of the affected regions and the amount of increase. The hippocampus, parahippocampal gyrus and cingulum were the most significantly affected regions in AD patients. From all the 90 cerebral cortex regions, significant increase of MD in the AD patients was found in 40 regions, compared to only one (fusiform gyrus on the right) in aMCI patients. In the disease affected regions, the MD from aMCI patients is in state between NC and AD patients. Conclusions: Increased MD in the specific regions of the brain shows the feasibility of MD as an indicator of the early stage cortical degeneration in aMCI and AD patients. PMID:28123367

  5. Air Pollution

    MedlinePlus

    Air pollution is a mixture of solid particles and gases in the air. Car emissions, chemicals from factories, ... Ozone, a gas, is a major part of air pollution in cities. When ozone forms air pollution, it's ...

  6. Cross-Polar Aircraft Trajectory Optimization and Potential Climate Impact

    NASA Technical Reports Server (NTRS)

    Sridhar, Banavar; Chen, Neil; Ng, Hok

    2011-01-01

    Cross-Polar routes offer new opportunities for air travel markets. Transpolar flights reduce travel times, fuel burns, and associated environmental emissions by flying direct paths between many North American and Asian cities. This study evaluates the potential benefits of flying wind-optimal polar routes and assessed their potential impact on climate change. An optimization algorithm is developed for transpolar flights to generate wind-optimal trajectories that minimize climate impact of aircraft, in terms of global warming potentials (relative to warming by one kg of CO2) of several types of emissions, while avoiding regions of airspace that facilitate persistent contrail formation. Estimations of global warming potential are incorporated into the objective function of the optimization algorithm to assess the climate impact of aircraft emissions discharged at a given location and altitude. The regions of airspace with very low ambient temperature and areas favorable to persistent contrail formation are modeled as undesirable regions that aircraft should avoid and are formulated as soft state constraints. The fuel burn and climate impact of cross-polar air traffic flying various types of trajectory including flightplan, great circle, wind-optimal, and contrail-avoidance are computed for 15 origin-destination pairs between major international airports in the U.S. and Asia. Wind-optimal routes reduce average fuel burn of flight plan routes by 4.4% on December 4, 2010 and 8.0% on August 7, 2010, respectively. The tradeoff between persistent contrail formation and additional global warming potential of aircraft emissions is investigated with and without altitude optimization. Without altitude optimization, the reduction in contrail travel times is gradual with increase in total fuel consumption. When altitude is optimized, a one percent increase in additional global warming potential, a climate impact equivalent to that of 4070kg and 4220kg CO2 emission, reduces 135

  7. Analysis of observations and modeling of criteria pollutants and photochemical age indicators during MILAGRO at Tenango del Aire

    NASA Astrophysics Data System (ADS)

    Ruiz Suarez, L. G.

    2009-04-01

    We report measurements and modeling results from the mobile air quality monitoring unit and other instruments in Tenango del Aire (TA). Tenango del Aire is a small town in the mountain pass between the Siera de Chichinautzin and the Popocatepel and Iztachiuatl Volcanos. The pass joins the Valley of Mexico and the Valley of Cuernavaca. TA was the most shouter and equipped site on that flank of MILAGRO. We compare model results and measurements of O3, NOx, NOy, CO, SO2, CH2O, mixing high and some VOC speciated analysis. Indicators of photochemical age as O3/CO, NOy/CO, are also reported. Mean hourly averages for all the campaign are reported. Specific episodes are also analyzed in depth. Evidence of a polluted regional background atmosphere is shown. The basic average surface transport patern was as follows, from 09:00 to 12:00 winds from the north arrive to TA bringing fresh polluted parcels from the highly populated sowtheast parts of the MCMA. Between 12:00 and 13:00 hours a shift of wind direction brings back those or parts of those parcels and parcels farer away. Most of the times, this conditions continues until next morning when for few hours air again drains south from the valley of Mexico. Ozone reaches a maximum value between 12:00 and 13:00, and these values stay still until after 18:00. Average value of this plateau is 80 ppb. During this plateau indicators as O3/CO and NOy/CO show that air parcels passing over TA are photochemicaly aged.

  8. Scout trajectory error propagation computer program

    NASA Technical Reports Server (NTRS)

    Myler, T. R.

    1982-01-01

    Since 1969, flight experience has been used as the basis for predicting Scout orbital accuracy. The data used for calculating the accuracy consists of errors in the trajectory parameters (altitude, velocity, etc.) at stage burnout as observed on Scout flights. Approximately 50 sets of errors are used in Monte Carlo analysis to generate error statistics in the trajectory parameters. A covariance matrix is formed which may be propagated in time. The mechanization of this process resulted in computer program Scout Trajectory Error Propagation (STEP) and is described herein. Computer program STEP may be used in conjunction with the Statistical Orbital Analysis Routine to generate accuracy in the orbit parameters (apogee, perigee, inclination, etc.) based upon flight experience.

  9. On complex, curved trajectories in microtubule gliding

    NASA Astrophysics Data System (ADS)

    Gosselin, Pierre; Mohrbach, Hervé; Kulić, Igor M.; Ziebert, Falko

    2016-04-01

    We study the dynamics of microtubules in gliding assays. These biofilaments are typically considered as purely semiflexible, hence their trajectories under the action of motors covering the substrate have been regarded so far as straight, modulo fluctuations. However, this is not always the case experimentally, where microtubules are known to move on large scale circles or spirals, or even display quite regular wavy trajectories and more complex dynamics. Incorporating recent experimental evidence for a (small) preferred curvature as well as the microtubules' well established lattice twist into a dynamic model for microtubule gliding, we could reproduce both types of trajectories. Interestingly, as a function of the microtubules' length we found length intervals of stable rings alternating with regions where wavy and more complex dynamics prevails. Finally, both types of dynamics (rings and waves) can be rationalized by considering simple limits of the full model.

  10. 3D Visualization of Cooperative Trajectories

    NASA Technical Reports Server (NTRS)

    Schaefer, John A.

    2014-01-01

    Aerodynamicists and biologists have long recognized the benefits of formation flight. When birds or aircraft fly in the upwash region of the vortex generated by leaders in a formation, induced drag is reduced for the trail bird or aircraft, and efficiency improves. The major consequence of this is that fuel consumption can be greatly reduced. When two aircraft are separated by a large enough longitudinal distance, the aircraft are said to be flying in a cooperative trajectory. A simulation has been developed to model autonomous cooperative trajectories of aircraft; however it does not provide any 3D representation of the multi-body system dynamics. The topic of this research is the development of an accurate visualization of the multi-body system observable in a 3D environment. This visualization includes two aircraft (lead and trail), a landscape for a static reference, and simplified models of the vortex dynamics and trajectories at several locations between the aircraft.

  11. Robot Trajectories Comparison: A Statistical Approach

    PubMed Central

    Ansuategui, A.; Arruti, A.; Susperregi, L.; Yurramendi, Y.; Jauregi, E.; Lazkano, E.; Sierra, B.

    2014-01-01

    The task of planning a collision-free trajectory from a start to a goal position is fundamental for an autonomous mobile robot. Although path planning has been extensively investigated since the beginning of robotics, there is no agreement on how to measure the performance of a motion algorithm. This paper presents a new approach to perform robot trajectories comparison that could be applied to any kind of trajectories and in both simulated and real environments. Given an initial set of features, it automatically selects the most significant ones and performs a statistical comparison using them. Additionally, a graphical data visualization named polygraph which helps to better understand the obtained results is provided. The proposed method has been applied, as an example, to compare two different motion planners, FM2 and WaveFront, using different environments, robots, and local planners. PMID:25525618

  12. A new trajectory correction technique for linacs

    SciTech Connect

    Raubenheimer, T.O.; Ruth, R.D.

    1990-06-01

    In this paper, we describe a new trajectory correction technique for high energy linear accelerators. Current correction techniques force the beam trajectory to follow misalignments of the Beam Position Monitors. Since the particle bunch has a finite energy spread and particles with different energies are deflected differently, this causes chromatic'' dilution of the transverse beam emittance. The algorithm, which we describe in this paper, reduces the chromatic error by minimizing the energy dependence of the trajectory. To test the method we compare the effectiveness of our algorithm with a standard correction technique in simulations on a design linac for a Next Linear Collider. The simulations indicate that chromatic dilution would be debilitating in a future linear collider because of the very small beam sizes required to achieve the necessary luminosity. Thus, we feel that this technique will prove essential for future linear colliders. 3 refs., 6 figs., 2 tabs.

  13. Developmental trajectories of bullying and associated factors.

    PubMed

    Pepler, Debra; Jiang, Depeng; Craig, Wendy; Connolly, Jennifer

    2008-01-01

    Trajectories in bullying through adolescence were studied along with individual, family, and peer relationship factors. At the outset, participants' ages ranged from 10 to 14; 74% identified as European Canadian with the remainder from diverse backgrounds. With 8 waves of data over 7 years, 871 students (466 girls and 405 boys) were studied to reveal 4 trajectories: 9.9% reported consistently high levels of bullying, 13.4% reported early moderate levels desisting to almost no bullying at the end of high school, 35.1% reported consistently moderate levels, and 41.6% almost never reported bullying. Students who bullied had elevated risks in individual, parent, and peer relationship domains. Risk profiles and trajectories provide direction for interventions to curtail the development of power and aggression in relationships.

  14. Analysis and prediction of stratospheric balloons trajectories

    NASA Astrophysics Data System (ADS)

    Cardillo, A.; Memmo, A.; Musso, I.; Ibba, R.; Spoto, D.

    The first step to manage a balloon flight from a trajectory point of view is the definition of launch location and period. Analysis data are used to realize a statistical study of the trajectories that can be obtained. The goal is define the conditions able to maximize the probability to respect mission objectives and constrains. Ones started with operations the balloon control centre has to manage the flight respecting safety and science. To predict stratospheric balloon trajectories we must utilize data from different forecast models and real-time measurements of wind and other meteorological entities. These sources of information have to be merged along the simulation of the balloon flight. Great attention has be paid for long duration flight from Pole and Equator, where QBO plays an important role.

  15. Romantic attraction and adolescent smoking trajectories.

    PubMed

    Pollard, Michael S; Tucker, Joan S; Green, Harold D; Kennedy, David P; Go, Myong-Hyun

    2011-12-01

    Research on sexual orientation and substance use has established that lesbian, gay, and bisexual (LGB) individuals are more likely to smoke than heterosexuals. This analysis furthers the examination of smoking behaviors across sexual orientation groups by describing how same- and opposite-sex romantic attraction, and changes in romantic attraction, are associated with distinct six-year developmental trajectories of smoking. The National Longitudinal Study of Adolescent Health dataset is used to test our hypotheses. Multinomial logistic regressions predicting smoking trajectory membership as a function of romantic attraction were separately estimated for men and women. Romantic attraction effects were found only for women. The change from self-reported heterosexual attraction to lesbian or bisexual attraction was more predictive of higher smoking trajectories than was a consistent lesbian or bisexual attraction, with potentially important differences between the smoking patterns of these two groups.

  16. Trajectory Software With Upper Atmosphere Model

    NASA Technical Reports Server (NTRS)

    Barrett, Charles

    2012-01-01

    The Trajectory Software Applications 6.0 for the Dec Alpha platform has an implementation of the Jacchia-Lineberry Upper Atmosphere Density Model used in the Mission Control Center for International Space Station support. Previous trajectory software required an upper atmosphere to support atmosphere drag calculations in the Mission Control Center. The Functional operation will differ depending on the end-use of the module. In general, the calling routine will use function-calling arguments to specify input to the processor. The atmosphere model will then compute and return atmospheric density at the time of interest.

  17. General Methodology for Designing Spacecraft Trajectories

    NASA Technical Reports Server (NTRS)

    Condon, Gerald; Ocampo, Cesar; Mathur, Ravishankar; Morcos, Fady; Senent, Juan; Williams, Jacob; Davis, Elizabeth C.

    2012-01-01

    A methodology for designing spacecraft trajectories in any gravitational environment within the solar system has been developed. The methodology facilitates modeling and optimization for problems ranging from that of a single spacecraft orbiting a single celestial body to that of a mission involving multiple spacecraft and multiple propulsion systems operating in gravitational fields of multiple celestial bodies. The methodology consolidates almost all spacecraft trajectory design and optimization problems into a single conceptual framework requiring solution of either a system of nonlinear equations or a parameter-optimization problem with equality and/or inequality constraints.

  18. A simple model of quantum trajectories

    NASA Astrophysics Data System (ADS)

    Brun, Todd A.

    2002-07-01

    Quantum trajectory theory, developed largely in the quantum optics community to describe open quantum systems subjected to continuous monitoring, has applications in many areas of quantum physics. I present a simple model, using two-level quantum systems (q-bits), to illustrate the essential physics of quantum trajectories and how different monitoring schemes correspond to different "unravelings" of a mixed state master equation. I also comment briefly on the relationship of the theory to the consistent histories formalism and to spontaneous collapse models.

  19. Trajectory surgical guide stent for implant placement.

    PubMed

    Adrian, E D; Ivanhoe, J R; Krantz, W A

    1992-05-01

    This article describes a new implant placement surgical guide that gives both implant location and trajectory to the surgeon. Radiopaque markers are placed on diagnostic dentures and a lateral cephalometric radiograph is made that shows the osseous anatomy at the symphysis and the anterior tooth location. The ideal implant location and trajectory data are transferred to a surgical stent that programs the angle and location of the fixtures at time of surgery. The stent has the additional benefit of acting as an occlusion rim, a mouth prop, and tongue retractor. Use of this stent has resulted in consistently programming the placement of implant fixtures that are prosthodontically ideal.

  20. Trajectories of Multi-lined Spatial Scans

    NASA Astrophysics Data System (ADS)

    McCullough, P.

    2017-03-01

    We compare multi-lined (a.k.a. boustrophedonic) spatial scans with numerical simulations of the trajectories using a simple physical model for HST's motions. For scan rates less than or equal to 0.5 arc sec s-1, the simulated trajectories match the observed ones within 0.5 arc sec, i.e. sufficiently well for planning purposes. We provide IDL procedures for the simulator in the Appendix. We identify an overall unexplained drift, primarily in the UVIS detector X direction, throughout the one HST orbit during visit 1 of program 14878.

  1. Optimal trajectories for the aeroassisted flight experiment

    NASA Technical Reports Server (NTRS)

    Miele, A.; Wang, T.; Lee, W. Y.; Zhao, Z. G.

    1989-01-01

    The determination of optimal trajectories for the aeroassisted flight experiment (AFE) is discussed. The intent of this experiment is to simulate a GEO-to-LEO transfer, where GEO denotes a geosynchronous earth orbit and LEO denotes a low earth orbit. The trajectories of an AFE spacecraft are analyzed in a 3D-space, employing the full system of 6 ordinary differential equations (ODEs) describing the atmospheric pass. The atmospheric entry conditions are given, and the atmospheric exit conditions are adjusted. Two possible transfers are considered: (1) indirect ascent to a 178 NM perigee via a 197 NM apogee; and (2) direct ascent to a 178 NM apogee.

  2. PTM Along Track Algorithm to Maintain Spacing During Same Direction Pair-Wise Trajectory Management Operations

    NASA Technical Reports Server (NTRS)

    Carreno, Victor A.

    2015-01-01

    Pair-wise Trajectory Management (PTM) is a cockpit based delegated responsibility separation standard. When an air traffic service provider gives a PTM clearance to an aircraft and the flight crew accepts the clearance, the flight crew will maintain spacing and separation from a designated aircraft. A PTM along track algorithm will receive state information from the designated aircraft and from the own ship to produce speed guidance for the flight crew to maintain spacing and separation

  3. Chopper Gun Trajectory Optimization for Spray Forming in Automotive Manufacturing

    NASA Astrophysics Data System (ADS)

    Chen, Heping; Xi, Ning; Sheng, Weihua; Chen, Yifan; Dahl, Jeffrey

    2004-06-01

    Automatic chopper gun trajectory generation for spray forming is highly desirable for today's automotive manufacturing. Generating chopper gun trajectories for free-form surfaces to satisfy thickness requirements is still highly challenging due to the complex geometry of free-form surfaces. A CAD-guided chopper gun trajectory generation system for free-form surfaces has been developed in our previous work. A complex surface has to be divided into several patches to satisfy the given constraints. Optimization algorithms are developed to integrate the trajectories of patches to form a trajectory for the free-form surface. A thickness verification method is also provided to verify the generated trajectories. The results of experiments and simulations have shown that the trajectory generation system achieves satisfactory performance. This trajectory generation method can also be applied in many other CAD-guided robot trajectory planning applications.

  4. Trajectory Browser: An online tool for interplanetary trajectory analysis and visualization

    NASA Astrophysics Data System (ADS)

    Foster, C.

    The Trajectory Browser is a web-based tool developed at the NASA Ames Research Center for finding preliminary trajectories to planetary bodies and for providing relevant launch date, time-of-flight and Δ V requirements. The site hosts a database of transfer trajectories from Earth to planets and small-bodies for various types of missions such as rendezvous, sample return or flybys. A search engine allows the user to find trajectories meeting desired constraints on the launch window, mission duration and Δ V capability, while a trajectory viewer tool allows the visualization of the heliocentric trajectory and the detailed mission itinerary. The anticipated user base of this tool consists primarily of scientists and engineers designing interplanetary missions in the context of pre-phase A studies, particularly for performing accessibility surveys to large populations of small-bodies. The educational potential of the website is also recognized for academia and the public with regards to trajectory design, a field that has generally been poorly understood by the public. The website is currently hosted on NASA-internal URL http://trajbrowser.arc.nasa.gov/ with plans for a public release in early 2013.

  5. Huygens probe entry, descent, and landing trajectory reconstruction using the Program to Optimize Simulated Trajectories II

    NASA Astrophysics Data System (ADS)

    Striepe, Scott Allen

    The objectives of this research were to develop a reconstruction capability using the Program to Optimize Simulated Trajectories II (POST2), apply this capability to reconstruct the Huygens Titan probe entry, descent, and landing (EDL) trajectory, evaluate the newly developed POST2 reconstruction module, analyze the reconstructed trajectory, and assess the pre-flight simulation models used for Huygens EDL simulation. An extended Kalman filter (EKF) module was developed and integrated into POST2 to enable trajectory reconstruction (especially when using POST2-based mission specific simulations). Several validation cases, ranging from a single, constant parameter estimate to multivariable estimation cases similar to an actual mission flight, were executed to test the POST2 reconstruction module. Trajectory reconstruction of the Huygens entry probe at Titan was accomplished using accelerometer measurements taken during flight to adjust an estimated state (e.g., position, velocity, parachute drag, wind velocity, etc.) in a POST2-based simulation developed to support EDL analyses and design prior to entry. Although the main emphasis of the trajectory reconstruction was to evaluate models used in the NASA pre-entry trajectory simulation, the resulting reconstructed trajectory was also assessed to provide an independent evaluation of the ESA result. Major findings from this analysis include: Altitude profiles from this analysis agree well with other NASA and ESA results but not with Radar data, whereas a scale factor of about 0.93 would bring the radar measurements into compliance with these results; entry capsule aerodynamics predictions (axial component only) were well within 3-sigma bounds established pre-flight for most of the entry when compared to reconstructed values; Main parachute drag of 9% to 19% above ESA model was determined from the reconstructed trajectory; based on the tilt sensor and accelerometer data, the conclusion from this assessment was that the

  6. A Potentially Useful for Airborne Separation in 4D-Trajectory ATM Operations

    NASA Technical Reports Server (NTRS)

    Wing, David J.

    2005-01-01

    An aircraft equipped with Airborne Separation Assistance System functions and 4- dimensional trajectory management capabilities can have significant, potentially transforming, value to Air Traffic Management at the local and system levels. This paper discusses how certain vital characteristics envisioned in the Next Generation Air Transportation System enable some Air Traffic Management functions to be distributed to properly equipped aircraft, and it defines and illustrates this equipage level in a potential application. The new equipage level, perhaps the most capable of many levels permitted, enables an effective implementation of both near- and long-term 4-dimensional trajectory operations in complex airspace, with the aircraft providing the near-term tactical functions and conforming to the long-term trajectory attributes coordinated with ground-based Traffic Flow Management authorities. NASA s recent research and development of this proposed aircraft equipage for en-route and terminal-arrival operations is summarized. The role the equipage level may play in addressing key implementation challenges of reducing ground infrastructure cost, building in security and safety, and scaling to traffic demand is discussed.

  7. Hi-G electronic gated camera for precision trajectory analysis

    NASA Astrophysics Data System (ADS)

    Snyder, Donald R.; Payne, Scott; Keller, Ed; Longo, Salvatore; Caudle, Dennis E.; Walker, Dennis C.; Sartor, Mark A.; Keeler, Joe E.; Kerr, David A.; Fail, R. Wallace; Gannon, Jim; Carrol, Ernie; Jamison, Todd A.

    1997-12-01

    It is extremely difficult and expensive to determine the flight attitude and aimpoint of small maneuvering miniature air vehicles from ground based fixed or tracking photography. Telemetry alone cannot provide sufficient information bandwidth on 'what' the ground tracking is seeing and consequently 'why' it did or did not function properly. Additionally, it is anticipated that 'smart' and 'brilliant' guided vehicles now in development will require a high resolution imaging support system to determine which target and which part of a ground feature is being used for navigation or targeting. Other requirements include support of sub-component separation from developmental supersonic vehicles, where the clean separation from the container is not determinable from ground based film systems and film cameras do not survive vehicle breakup and impact. Hence, the requirement is to develop and demonstrate an imaging support system for development/testing that can provide the flight vehicle developer/analyst with imagery (combined with miniature telemetry sources) sufficient to recreate the trajectory, terminal navigation, and flight termination events. This project is a development and demonstration of a real-time, launch-rated, shuttered, electronic imager, transmitter, and analysis system. This effort demonstrated boresighted imagery from inside small flight vehicles for post flight analysis of trajectory, and capture of ground imagery during random triggered vehicle functions. The initial studies for this capability have been accomplished by the Experimental Dynamics Section of the Air Force Wright Laboratory, Armament Directorate, Eglin AFB, Florida, and the Telemetry Support Branch of the Army Material Research and Development Center at Picatinny Arsenal, New Jersey. It has been determined that at 1/10,000 of a second exposure time, new ultra-miniature CCD sensors have sufficient sensitivity to image key ground target features without blur, thereby providing data for

  8. Bohmian quantum mechanics with quantum trajectories

    NASA Astrophysics Data System (ADS)

    Jeong, Yeuncheol

    The quantum trajectory method in the hydrodynamical formulation of Madelung-Bohm-Takabayasi quantum mechanics is an example of showing the cognitive importance of scientific illustrations and metaphors, especially, in this case, in computational quantum chemistry and electrical engineering. The method involves several numerical schemes of solving a set of hydrodynamical equations of motion for probability density fluids, based on the propagation of those probability density trajectories. The quantum trajectory method gives rise to, for example, an authentic quantum electron transport theory of motion to, among others, classically-minded applied scientists who probably have less of a commitment to traditional quantum mechanics. They were not the usual audience of quantum mechanics and simply choose to use a non-Copenhagen type interpretation to their advantage. Thus, the metaphysical issues physicists had a trouble with are not the main concern of the scientists. With the advantages of a visual and illustrative trajectory, the quantum theory of motion by Bohm effectively bridges quantum and classical physics, especially, in the mesoscale domain. Without having an abrupt shift in actions and beliefs from the classical to the quantum world, scientists and engineers are able to enjoy human cognitive capacities extended into the quantum mechanical domain.

  9. Establishing cycler trajectories between Earth and Mars

    NASA Astrophysics Data System (ADS)

    Rogers, Blake A.; Hughes, Kyle M.; Longuski, James M.; Aldrin, Buzz

    2015-07-01

    Several cycler concepts have been proposed to provide safe and comfortable quarters for astronauts traveling between the Earth and Mars. However, no literature has appeared to show how these massive vehicles might be placed into their cycler trajectories. In this paper, trajectories are designed that use either V∞ leveraging or low thrust to establish cycler vehicles in their desired orbits. In the cycler trajectory cases considered, the use of V∞ leveraging or low thrust substantially reduces the total propellant needed to achieve the cycler orbit compared to direct orbit insertion. In the case of the classic Aldrin cycler, the propellant savings due to V∞ leveraging can be as large as 24 metric tons for a cycler vehicle with a dry mass of 75 metric tons, and an additional 111 metric tons by instead using low thrust. The two-synodic period cyclers considered benefit less from V∞ leveraging, but have a smaller total propellant mass due to their lower approach velocities at Earth and Mars. It turns out that, for low-thrust establishment, the propellant required is approximately the same for each of the cycler trajectories. The cycler concept may provide a crucial enabling technology that is safe, economical, and sustainable for the continuous habitation of Mars.

  10. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the requirements of paragraph (a) of this section. (c) Wind effects. A trajectory analysis must account for all wind effects, including profiles of winds that are no less severe than the worst wind conditions under which flight might be attempted, and must account for uncertainty in the wind conditions....

  11. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the requirements of paragraph (a) of this section. (c) Wind effects. A trajectory analysis must account for all wind effects, including profiles of winds that are no less severe than the worst wind conditions under which flight might be attempted, and must account for uncertainty in the wind conditions....

  12. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the requirements of paragraph (a) of this section. (c) Wind effects. A trajectory analysis must account for all wind effects, including profiles of winds that are no less severe than the worst wind conditions under which flight might be attempted, and must account for uncertainty in the wind conditions....

  13. Performance of Trajectory Models with Wind Uncertainty

    NASA Technical Reports Server (NTRS)

    Lee, Alan G.; Weygandt, Stephen S.; Schwartz, Barry; Murphy, James R.

    2009-01-01

    Typical aircraft trajectory predictors use wind forecasts but do not account for the forecast uncertainty. A method for generating estimates of wind prediction uncertainty is described and its effect on aircraft trajectory prediction uncertainty is investigated. The procedure for estimating the wind prediction uncertainty relies uses a time-lagged ensemble of weather model forecasts from the hourly updated Rapid Update Cycle (RUC) weather prediction system. Forecast uncertainty is estimated using measures of the spread amongst various RUC time-lagged ensemble forecasts. This proof of concept study illustrates the estimated uncertainty and the actual wind errors, and documents the validity of the assumed ensemble-forecast accuracy relationship. Aircraft trajectory predictions are made using RUC winds with provision for the estimated uncertainty. Results for a set of simulated flights indicate this simple approach effectively translates the wind uncertainty estimate into an aircraft trajectory uncertainty. A key strength of the method is the ability to relate uncertainty to specific weather phenomena (contained in the various ensemble members) allowing identification of regional variations in uncertainty.

  14. Hyper-X Mach 10 Trajectory Reconstruction

    NASA Technical Reports Server (NTRS)

    Karlgaard, Christopher D.; Martin, John G.; Tartabini, Paul V.; Thornblom, Mark N.

    2005-01-01

    This paper discusses the formulation and development of a trajectory reconstruction tool for the NASA X-43A/Hyper-X high speed research vehicle, and its implementation for the reconstruction and analysis of flight test data. Extended Kalman filtering techniques are employed to reconstruct the trajectory of the vehicle, based upon numerical integration of inertial measurement data along with redundant measurements of the vehicle state. The equations of motion are formulated in order to include the effects of several systematic error sources, whose values may also be estimated by the filtering routines. Additionally, smoothing algorithms have been implemented in which the final value of the state (or an augmented state that includes other systematic error parameters to be estimated) and covariance are propagated back to the initial time to generate the best-estimated trajectory, based upon all available data. The methods are applied to the problem of reconstructing the trajectory of the Hyper-X vehicle from data obtained during the Mach 10 test flight, which occurred on November 16th 2004.

  15. Graphical Method for Determining Projectile Trajectory

    ERIC Educational Resources Information Center

    Moore, J. C.; Baker, J. C.; Franzel, L.; McMahon, D.; Songer, D.

    2010-01-01

    We present a nontrigonometric graphical method for predicting the trajectory of a projectile when the angle and initial velocity are known. Students enrolled in a general education conceptual physics course typically have weak backgrounds in trigonometry, making inaccessible the standard analytical calculation of projectile range. Furthermore,…

  16. Developmental Trajectories of Bullying and Associated Factors

    ERIC Educational Resources Information Center

    Pepler, Debra; Jiang, Depeng; Craig, Wendy; Connolly, Jennifer

    2008-01-01

    Trajectories in bullying through adolescence were studied along with individual, family, and peer relationship factors. At the outset, participants' ages ranged from 10 to 14; 74% identified as European Canadian with the remainder from diverse backgrounds. With 8 waves of data over 7 years, 871 students (466 girls and 405 boys) were studied to…

  17. Causal Inferences with Group Based Trajectory Models

    ERIC Educational Resources Information Center

    Haviland, Amelia M.; Nagin, Daniel S.

    2005-01-01

    A central theme of research on human development and psychopathology is whether a therapeutic intervention or a turning-point event, such as a family break-up, alters the trajectory of the behavior under study. This paper lays out and applies a method for using observational longitudinal data to make more confident causal inferences about the…

  18. Families of Ellipses and their Orthogonal Trajectories

    ERIC Educational Resources Information Center

    Ayoub, Ayoub B.

    2004-01-01

    The topic of orthogonal trajectories is taught as a geometric application of first order differential equations. Instructors usually elaborate on the concept of a family of curves to emphasize that they are different even if their members are of the same type. In this article the author considers five families of ellipses, discusses their…

  19. Developmental Trajectories of Early Communication Skills

    ERIC Educational Resources Information Center

    Maatta, Sira; Laakso, Marja-Leena; Tolvanen, Asko; Ahonen, Timo; Aro, Tuija

    2012-01-01

    Purpose: This study focused on developmental trajectories of prelinguistic communication skills and their connections to later parent-reported language difficulties. Method: The participants represent a subset of a community-based sample of 508 children. Data include parent reports of prelinguistic communication skills at 12, 15, 18, and 21 months…

  20. Trajectory optimization for the National aerospace plane

    NASA Technical Reports Server (NTRS)

    Lu, Ping

    1993-01-01

    While continuing the application of the inverse dynamics approach in obtaining the optimal numerical solutions, the research during the past six months has been focused on the formulation and derivation of closed-form solutions for constrained hypersonic flight trajectories. Since it was found in the research of the first year that a dominant portion of the optimal ascent trajectory of the aerospace plane is constrained by dynamic pressure and heating constraints, the application of the analytical solutions significantly enhances the efficiency in trajectory optimization, provides a better insight to understanding of the trajectory and conceivably has great potential in guidance of the vehicle. Work of this period has been reported in four technical papers. Two of the papers were presented in the AIAA Guidance, Navigation, and Control Conference (Hilton Head, SC, August, 1992) and Fourth International Aerospace Planes Conference (Orlando, FL, December, 1992). The other two papers have been accepted for publication by Journal of Guidance, Control, and Dynamics, and will appear in 1993. This report briefly summarizes the work done in the past six months and work currently underway.

  1. Using Developmental Trajectories to Understand Developmental Disorders

    ERIC Educational Resources Information Center

    Thomas, Michael S. C.; Annaz, Dagmara; Ansari, Daniel; Scerif, Gaia; Jarrold, Chris; Karmiloff-Smith, Annette

    2009-01-01

    Purpose: In this article, the authors present a tutorial on the use of developmental trajectories for studying language and cognitive impairments in developmental disorders and compare this method with the use of matching. Method: The authors assess the strengths, limitations, and practical implications of each method. The contrast between the…

  2. Nonlinear Optimal Trajectories Using Successive Linearization

    DTIC Science & Technology

    1977-06-28

    integral sign represents a penalty for the local vertical and passing through the vehicle deviations of the perturbed trajectory from the at time equals... integral sign represents the penalty for control variations about the nominal, and needs z s - sin y (14) to be weighted to ensure that the control does

  3. Fractal aircraft trajectories and nonclassical turbulent exponents.

    PubMed

    Lovejoy, S; Schertzer, D; Tuck, A F

    2004-09-01

    The dimension (D) of aircraft trajectories is fundamental in interpreting airborne data. To estimate D, we studied data from 18 trajectories of stratospheric aircraft flights 1600 km long taken during a "Mach cruise" (near constant Mach number) autopilot flight mode of the ER-2 research aircraft. Mach cruise implies correlated temperature and wind fluctuations so that DeltaZ approximately Deltax (H(z) ) where Z is the (fluctuating) vertical and x the horizontal coordinate of the aircraft. Over the range approximately 3-300 km , we found H(z) approximately 0.58+/-0.02 close to the theoretical 5/9=0.56 and implying D=1+ H(z) =14/9 , i.e., the trajectories are fractal. For distances <3 km aircraft inertia smooths the trajectories, for distances >300 km , D=1 again because of a rise of 1 m/km due to fuel consumption. In the fractal regime, the horizontal velocity and temperature exponents are close to the nonclassical value 1/2 (rather than 1/3 ). We discuss implications for aircraft measurements as well as for the structure of the atmosphere.

  4. Equilibrium sampling by reweighting nonequilibrium simulation trajectories.

    PubMed

    Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin

    2016-03-01

    Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.

  5. Academic Trajectories of Newcomer Immigrant Youth

    ERIC Educational Resources Information Center

    Suarez-Orozco, Carola; Gaytan, Francisco X.; Bang, Hee Jin; Pakes, Juliana; O'Connor, Erin; Rhodes, Jean

    2010-01-01

    Immigration to the United States presents both challenges and opportunities that affect students' academic achievement. Using a 5-year longitudinal, mixed-methods approach, we identified varying academic trajectories of newcomer immigrant students from Central America, China, the Dominican Republic, Haiti, and Mexico. Latent class growth curve…

  6. Are U-Shaped Developmental Trajectories Illusory?

    ERIC Educational Resources Information Center

    Vouloumanos, Athena

    2011-01-01

    Without criteria for what counts as a U/N-shaped developmental trajectory, it is not clear how many legitimate "Us" really exist. Many, if not all, "Us" may turn out to be illusions borne out of our sampling methods, task construal, and blurry lenses of description. (Contains 2 figures.)

  7. Equilibrium sampling by reweighting nonequilibrium simulation trajectories

    NASA Astrophysics Data System (ADS)

    Yang, Cheng; Wan, Biao; Xu, Shun; Wang, Yanting; Zhou, Xin

    2016-03-01

    Based on equilibrium molecular simulations, it is usually difficult to efficiently visit the whole conformational space of complex systems, which are separated into some metastable regions by high free energy barriers. Nonequilibrium simulations could enhance transitions among these metastable regions and then be applied to sample equilibrium distributions in complex systems, since the associated nonequilibrium effects can be removed by employing the Jarzynski equality (JE). Here we present such a systematical method, named reweighted nonequilibrium ensemble dynamics (RNED), to efficiently sample equilibrium conformations. The RNED is a combination of the JE and our previous reweighted ensemble dynamics (RED) method. The original JE reproduces equilibrium from lots of nonequilibrium trajectories but requires that the initial distribution of these trajectories is equilibrium. The RED reweights many equilibrium trajectories from an arbitrary initial distribution to get the equilibrium distribution, whereas the RNED has both advantages of the two methods, reproducing equilibrium from lots of nonequilibrium simulation trajectories with an arbitrary initial conformational distribution. We illustrated the application of the RNED in a toy model and in a Lennard-Jones fluid to detect its liquid-solid phase coexistence. The results indicate that the RNED sufficiently extends the application of both the original JE and the RED in equilibrium sampling of complex systems.

  8. Statcast and the Baseball Trajectory Calculator

    NASA Astrophysics Data System (ADS)

    Kagan, David; Nathan, Alan M.

    2017-03-01

    Baseball's flirtation with technology began in 2005 when PITCHf/x® by Sportvision started to be installed in major league ballparks. Every stadium had the system operational by 2007. Since then, the trajectories of over six million pitches have been measured to within about half an inch using three 60-Hz video cameras to track the position of the ball.

  9. Technical Seminar: "Trajectory-Based Operations"""

    NASA Video Gallery

    A safe and efficient air traffic management system is vital to the nation's economy. This seminar explores the concepts and current research into air traffic control concepts that focus on more dim...

  10. Parallel Aircraft Trajectory Optimization with Analytic Derivatives

    NASA Technical Reports Server (NTRS)

    Falck, Robert D.; Gray, Justin S.; Naylor, Bret

    2016-01-01

    Trajectory optimization is an integral component for the design of aerospace vehicles, but emerging aircraft technologies have introduced new demands on trajectory analysis that current tools are not well suited to address. Designing aircraft with technologies such as hybrid electric propulsion and morphing wings requires consideration of the operational behavior as well as the physical design characteristics of the aircraft. The addition of operational variables can dramatically increase the number of design variables which motivates the use of gradient based optimization with analytic derivatives to solve the larger optimization problems. In this work we develop an aircraft trajectory analysis tool using a Legendre-Gauss-Lobatto based collocation scheme, providing analytic derivatives via the OpenMDAO multidisciplinary optimization framework. This collocation method uses an implicit time integration scheme that provides a high degree of sparsity and thus several potential options for parallelization. The performance of the new implementation was investigated via a series of single and multi-trajectory optimizations using a combination of parallel computing and constraint aggregation. The computational performance results show that in order to take full advantage of the sparsity in the problem it is vital to parallelize both the non-linear analysis evaluations and the derivative computations themselves. The constraint aggregation results showed a significant numerical challenge due to difficulty in achieving tight convergence tolerances. Overall, the results demonstrate the value of applying analytic derivatives to trajectory optimization problems and lay the foundation for future application of this collocation based method to the design of aircraft with where operational scheduling of technologies is key to achieving good performance.

  11. Querying databases of trajectories of differential equations: Data structures for trajectories

    NASA Technical Reports Server (NTRS)

    Grossman, Robert

    1989-01-01

    One approach to qualitative reasoning about dynamical systems is to extract qualitative information by searching or making queries on databases containing very large numbers of trajectories. The efficiency of such queries depends crucially upon finding an appropriate data structure for trajectories of dynamical systems. Suppose that a large number of parameterized trajectories gamma of a dynamical system evolving in R sup N are stored in a database. Let Eta is contained in set R sup N denote a parameterized path in Euclidean Space, and let the Euclidean Norm denote a norm on the space of paths. A data structure is defined to represent trajectories of dynamical systems, and an algorithm is sketched which answers queries.

  12. Identifying Patterns of FEES-Derived Swallowing Trajectories Using Group-Based Trajectory Model.

    PubMed

    Baijens, Laura W J; Pilz, Walmari; Kremer, Bernd; Passos, Valeria Lima

    2015-10-01

    The present study delineates and visualizes swallowing trajectories along seven swallow trials in dysphagic patients using group-based trajectory modeling (GBTM). This model facilitates the recognition of swallowing functional categories, estimates their frequency of occurrence, and enhances the understanding of swallowing dynamics. Two hundred and five dysphagic patients underwent a standardized FEES examination protocol. Five ordinal variables were blindly assessed for each swallow by two observers independently. GBTM analysis was conducted to find and characterize trajectories of FEES responses. For most FEES outcome variables, trajectories were qualitatively distinct in degree and kind (level of impairment and how this changed over the seven swallow trials). Two FEES outcome variables-delayed initiation of the pharyngeal reflex and postswallow pyriform sinus pooling-showed the highest prevalence of severe swallowing impairment. Highly impaired categories were more stable throughout the different swallow trials. Intermediate trajectories, by contrast, were erratic, responding more sensitively to shifts in bolus consistency. GBTM can identify distinct developmental trajectories of measured FEES variables in patients with oropharyngeal dysphagia. In clinical practice, classification into distinct groups would help to identify the subgroup of dysphagic patients who may need specific medical attention.

  13. Reentry trajectory optimization based on a multistage pseudospectral method.

    PubMed

    Zhao, Jiang; Zhou, Rui; Jin, Xuelian

    2014-01-01

    Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization.

  14. Reentry Trajectory Optimization Based on a Multistage Pseudospectral Method

    PubMed Central

    Zhou, Rui; Jin, Xuelian

    2014-01-01

    Of the many direct numerical methods, the pseudospectral method serves as an effective tool to solve the reentry trajectory optimization for hypersonic vehicles. However, the traditional pseudospectral method is time-consuming due to large number of discretization points. For the purpose of autonomous and adaptive reentry guidance, the research herein presents a multistage trajectory control strategy based on the pseudospectral method, capable of dealing with the unexpected situations in reentry flight. The strategy typically includes two subproblems: the trajectory estimation and trajectory refining. In each processing stage, the proposed method generates a specified range of trajectory with the transition of the flight state. The full glide trajectory consists of several optimal trajectory sequences. The newly focused geographic constraints in actual flight are discussed thereafter. Numerical examples of free-space flight, target transition flight, and threat avoidance flight are used to show the feasible application of multistage pseudospectral method in reentry trajectory optimization. PMID:24574929

  15. Least Action Principle on an Air Table

    ERIC Educational Resources Information Center

    Provost, J. P.

    1975-01-01

    Presents a mathematical demonstration that the least action principle enables both the trajectories and the conservation laws (of energy, momentum, and angular momentum) to be obtained without using Lagrange's equations. Discusses an experimental procedure which utilizes air tables to demonstrate the conservation laws and interactions at a…

  16. Optimal trajectories for the aeroassisted flight experiment

    NASA Astrophysics Data System (ADS)

    Miele, A.; Wang, T.; Lee, W. Y.; Zhao, Z. G.

    This paper deals with the determination of optimal trajectories for the aeroassisted flight experiment (AFE). The intent of this experiment is to simulate a GEO-to-LEO transfer, where GEO denotes a geosynchronous Earth orbit and LEO denotes a low Earth orbit. Specifically, the AFE spacecraft is released from the Space Shuttle and is accelerated by means of a solid rocket motor toward Earth, so as to achieve atmospheric entry conditions identical with those of a spacecraft returning from GEO. During the atmospheric pass, the angle of attack is kept constant, and the angle of bank is controlled in such a way that the following conditions are satisfied: (a) the atmospheric velocity depletion is such that, after exiting, the AFE spacecraft first ascends to a specified apogee and then descends to a specified perigee; and (b) the exit orbital plane is identical with the entry orbital plane. The final maneuver, not analyzed here, includes the rendezvous with and the capture by the Space Shuttle. In this paper, the trajectories of an AFE spacecraft are analyzed in a 3D space, employing the full system of 6 ODEs describing the atmospheric pass. The atmospheric entry conditions are given, and the atmospheric exit conditions are adjusted in such a way that requirements (a) and (b) are met, while simultaneously minimizing the total characteristic velocity, hence the propellant consumption required for orbital transfer. Two possible transfers are considered: indirect ascent (IA) to a 178 NM perigee via a 197 NM apogee; and direct ascent (DA) to a 178 NM apogee. For both transfers, two cases are investigated: (i) the bank angle is continuously variable; and (ii) the trajectory is divided into segments along which the bank angle is constant. For case (ii), the following subcases are studied; 2, 3, 4 and 5 segments; because the time duration of each segment is optimized, the above subcases involve 4, 6, 8 and 10 parameters, respectively. It is shown that the optimal trajectories

  17. CISLUNAR program manual: A low-thrust trajectory determination model

    NASA Technical Reports Server (NTRS)

    1988-01-01

    CISLUNAR is a stand-alone computer program designed to generate the trajectory of a low-thrust spacecraft travelling in Earth-Moon space. The program allows the creation of functional trajectories dependent on the supplied spacecraft characteristics. The trajectory generation is a user interactive process. The original intent was for the program user to modify the necessary control values until a staisfactory trajectory has been created.

  18. Trajectory selection for the Mariner Jupiter/Saturn 1977 project

    NASA Technical Reports Server (NTRS)

    Dyer, J. S.; Miles, R. F., Jr.

    1974-01-01

    The use of decision analysis to facilitate a group decision-making problem in the selection of trajectories for the two spacecraft of the Mariner Jupiter/Saturn 1977 Project. A set of 32 candidate trajectory pairs was developed. Cardinal utility function values were assigned to the trajectory pairs, and the data and statistics derived from collective choice rules were used in selecting the science-preferred trajectory pair.

  19. Feasibility Study for Integrated Flight Trajectory Control (Fighter).

    DTIC Science & Technology

    1979-11-01

    ntamber) Flight Trajectory C.ntrol Control Law Development Profile Synthesis Tactical Situation Display Four -Dimensional Navigation Vertical Situation...realtime trajectory generation was developed as a vital part of the total solution. This trajectory, generator operates in four dimensions, X, Y...FLIGHT PROFILE SYNTHESIS 5-1 5.1 Four -Dimensional Trajectory Generator 5-1 5.1.1 Waypoint Parameters 5-1 5.1.2 Threat Avoidance 5-2 5.1.3 Horizontal Path

  20. Joint University Program for Air Transportation Research, 1985

    NASA Technical Reports Server (NTRS)

    Morrell, Frederick R. (Compiler)

    1987-01-01

    Air transportation research being carried on at the Massachusetts Institute of Technology, Princeton University, and Ohio University is discussed. Global Positioning System experiments, Loran-C monitoring, inertial navigation, the optimization of aircraft trajectories through severe microbursts, fault tolerant flight control systems, and expert systems for air traffic control are among the topics covered.