Science.gov

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. 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.

  3. 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

  4. The Use of Compensated Aerological No-Lift Balloons to Determine Relatively Long-Term Dry-Air Parcel Trajectories.

    NASA Astrophysics Data System (ADS)

    Terliuc, Benjamin; Asculai, Ephraim; Doron, Eli

    1983-10-01

    A method to compensate the loss of buoyancy due to gas leakage from aerological no-lift balloons is presented. The method is implemented by means of a double vessel device that supplies a constant liquid outflow at constant temperature. It is shown that the average buoyancy loss rate dependence on temperature is almost perfectly matched by the outflow rate dependence on temperature when soya-bean oil is used. The device is simple, inexpensive and can be easily manufactured using standard laboratory equipment.A simple and safe method to carry no-lift systems to prefixed levels is also presented. It is based on a single 30 g pilot balloon provided with a gas leakage nozzle, inflated with H2 to a calibrated initial free-lift. The balloon is totally emptied at the required level, and remains suspended from the no-lift system.The whole system can be easily prepared under field conditions to be used in long travel-time studies of dry-air parcel trajectories in the atmosphere.An example of the use of the improved method over complex terrain is presented. A no-lift system provided with a 1680 MHz radiosonde transmitter, was tracked by two RD-65 radio-theodolites, to investigate the effects of the topographic structure of the Lake Kinneret (Sea of Galilee) area on the Mediterranean sea breeze summer regime. The system was tracked for at least one hour, following a trajectory with severe vertical variations. This increases our confidence in the ability to track much longer trajectories, if required.

  5. 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.

  6. Air parcel random walk and droplet spectra broadening in clouds.

    PubMed

    Turitsyn, K S

    2003-06-01

    We study the effect of turbulent flow on the droplet growth in a cloud during the condensation phase. Using the air parcel model, we describe analytically how the size distribution of droplets evolves at the different stages of parcel movement. We show that turbulent random walk superimposed on an accelerated ascent of the parcel makes the relative width of droplet distribution to grow initially as t(1/2) and then decay as t(-3/2).

  7. Parcellation of Infant Surface Atlas Using Developmental Trajectories of Multidimensional Cortical Attributes

    PubMed Central

    Li, Gang; Wang, Li; Gilmore, John H.; Lin, Weili; Shen, Dinggang

    2016-01-01

    Cortical surface atlases, equipped with anatomically and functionally defined parcellations, are of fundamental importance in neuroimaging studies. Typically, parcellations of surface atlases are derived based on the sulcal-gyral landmarks, which are extremely variable across individuals and poorly matched with microstructural and functional boundaries. Cortical developmental trajectories in infants reflect underlying changes of microstructures, which essentially determines the molecular organization and functional principles of the cortex, thus allowing better definition of developmentally, microstructurally, and functionally distinct regions, compared to conventional sulcal-gyral landmarks. Accordingly, a parcellation of infant cortical surface atlas was proposed, based on the developmental trajectories of cortical thickness in infants, revealing regional patterning of cortical growth. However, cortical anatomy is jointly characterized by biologically-distinct, multidimensional cortical attributes, i.e., cortical thickness, surface area, and local gyrification, each with its distinct genetic underpinning, cellular mechanism, and developmental trajectories. To date, the parcellations based on the development of surface area and local gyrification is still missing. To bridge this critical gap, for the first time, we parcellate an infant cortical surface atlas into distinct regions based solely on developmental trajectories of surface area and local gyrification, respectively. For each cortical attribute, we first nonlinearly fuse the subject-specific similarity matrices of vertices' developmental trajectories of all subjects into a single matrix, which helps better capture common and complementary information of the population than the conventional method of simple averaging of all subjects' matrices. Then, we perform spectral clustering based on this fused matrix. We have applied our method to parcellate an infant surface atlas using the developmental trajectories

  8. In situ observations of dehydrated air parcels advected horizontally in the Tropical Tropopause Layer of the western Pacific

    NASA Astrophysics Data System (ADS)

    Hasebe, F.; Fujiwara, M.; Nishi, N.; Shiotani, M.; Vömel, H.; Oltmans, S.; Takashima, H.; Saraspriya, S.; Komala, N.; Inai, Y.

    2007-02-01

    Water vapor observations by chilled-mirror hygrometers were conducted at Bandung, Indonesia (6.90° S, 107.60° E) and Tarawa, Kiribati (1.35° N, 172.91° E) in December 2003 to examine the efficiency of dehydration during horizontal advection in the tropical tropopause layer (TTL). Trajectory analyses based on bundles of isentropic trajectories suggest that the modification of air parcels' identity due to irreversible mixing by the branching-out and merging-in of nearby trajectories is found to be an important factor, in addition to the routes air parcels follow, for interpreting the water vapor concentrations observed by chilled-mirror frostpoint hygrometers in the TTL. Clear correspondence between the observed water vapor concentration and the estimated temperature history of air parcels is found showing that drier air parcels were exposed to lower temperatures than were more humid ones during advection. Although the number of observations is quite limited, the water content in the observed air parcels on many occasions was more than that expected from the minimum saturation mixing ratio during horizontal advection prior to sonde observations.

  9. Evolution of chemically processed air parcels in the lower stratosphere

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Douglass, Anne R.; Schoeberl, Mark R.

    1994-01-01

    Aircraft, ground-based, and satellite measurements indicate large concentrations of ClO in the lower stratosphere in and near the polar vortex. The amount of local ozone depletion caused by these large ClO concentrations will depend on the relative rates of ozone loss and ClO recovery. ClO recovery occurs when NO(x), from HNO3 photolysis, reacts with ClO to form ClONO2. We show that air parcels with large amounts of ClO will experience a subsequent ozone depletion that depends on the solar zenith angle. When the solar zenith angle is large in the middle of winter, the recovery of the ClO concentration in the parcel is slow relative to ozone depletion. In the spring, when the solar zenith angle is smaller, the ClO recovery is much faster. After ClO recovery, the chlorine chemistry has not returned to normal. The ClO has been converted to ClONO2. ClO production from further encounters with PSCs will be limited by the heterogeneous reaction of ClONO2 with water. Large ozone depletions, of the type seen in the Antarctic, occur only if there is significant irreversible denitrification in the air parcel.

  10. 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.

  11. 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

  12. 76 FR 77856 - International Mail Price Change for Inbound Air Parcel Post

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... service bonus eligibility and submission of annual inflation information from the Consumer Price Index for... may qualify for percentage ``bonuses'' to their base rate based upon their provision of certain value... International Bureau publishes an annual notice establishing the postal administration's parcel rates for...

  13. 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.

  14. 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.

  15. New particle-dependent parameterizations of heterogeneous freezing processes: sensitivity studies of convective clouds with an air parcel model

    NASA Astrophysics Data System (ADS)

    Diehl, K.; Mitra, S. K.

    2015-11-01

    Based on the outcome of laboratory results, new particle-dependent parameterizations of heterogeneous freezing were derived and used to improve and extend a two-dimensional spectral microphysics scheme. They include (1) a particle-type-dependent parameterization of immersion freezing using the numbers of active sites per mass, (2) a particle-type and size-resolved parameterization of contact freezing, and (3) a particle-type-dependent description of deposition freezing. The modified microphysical scheme was embedded in an adiabatic air parcel model with entrainment. Sensitivity studies were performed to simulate convective situations and to investigate the impact of ice nuclei concentrations and types on ice formation. As a central diagnostic parameter, the ice water fraction (IWF) was selected, which is the relation of the ice water content to the total amount of water in the condensed form. The following parameters were varied: initial aerosol particle number size distributions, types of ice nucleating particles, final temperature, and the fractions of potential ice nucleating particles. Single and coupled freezing processes were investigated. The results show that immersion freezing seems to be the most efficient process. Contact freezing is constrained by the collision kernel between supercooled drops and potential ice nucleating particles. The importance of deposition freezing lies in secondary ice formation; i.e., small ice particles produced by deposition nucleation trigger the freezing of supercooled drops by collisions. Thus, a broader ice particle spectrum is generated than that by immersion and contact freezing. During coupled immersion-contact and contact-deposition freezing no competition was observed, and both processes contribute to cloud ice formation but do not impede each other. As already suggested in the literature, mineral dust particles seem to be the most important ice nucleating particles. Biological particles are probably not involved in

  16. Second-stage trajectories of air-breathing space planes

    NASA Astrophysics Data System (ADS)

    Staufenbiel, R. W.

    1990-12-01

    Attention throughout the world has turned to the benefits that can be gained in space transportation by combining the features of aircraft and rockets. In the rocket-driven phase or stage, which follows the nearly horizontal air-breathing flight, a considerable change in the flight trajectory, a pullup maneuver, is necessary shortly before or after igniting the rocket engines. The change puts a burden on the first or the second stage and thereby reduces the payload. In this paper an optimal strategy for the rocket-propelled flight phase is developed that gives the smallest penalties on longitudinal acceleration and, therefore, on burnout mass. The strategy leads to a splitting of lift and thrust component normal to the flight direction. Two other control strategies are compared with the optimal procedure. Using a generic modeling of aerodynamic characteristics, the equations of motion are solved to assess the influence of initial conditions and of trajectory parameters on the burnout mass. Results of the study show the essential influence of the initial values of flight-path angle and Mach number on the rocket-propelled flight phase. Initial flight-path angle should not be lower than 5 deg. If a reasonable amount of payload and propellant for in-orbit operation should be carried, the dry-mass ratio of the second stage must come down to the range of 15 to 20, depending on the separation Mach number (5 to 6.5).

  17. 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.

  18. 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.

  19. 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.

  20. The Origin of Stratospheric Air

    NASA Astrophysics Data System (ADS)

    Schoeberl, M. R.; Dessler, A. E.; Wang, T.

    2012-12-01

    The domain-filling, forward trajectory calculation model developed by Schoeberl and Dessler [2011] is used to investigate the origin of air that enters the stratosphere, and the origin of the driest and wettest air parcels. We compare results from NASA's MERRA, NCEP's CFSR, and ECMWF's ERAi reanalyses in a non-convection simulation. The stratospheric air parcel origin is related to but distinct from the location of final dehydration zones. Final dehydration zones control stratospheric water vapor, but stratospheric air origin tells about the origin of non-water soluble constituents such as HCN or CO. The models broadly agree that stratospheric air parcel origins follow the ITCZ in winter with maxima over the tropical west Pacific and South America. The origins are more broadly dispersed in summer. Somewhat surprisingly, the seasonal cycle for the origins is small with most of the air parcels entering the stratosphere from 360K originate in non-DJF months. The origin of the wettest and driest parcels shows that the driest parcels (1-3 ppmv) originate in the tropical West Pacific while the wettest (6-10 ppmv) parcels originate in the East Pacific/ Central America.

  1. 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.

  2. 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...

  3. 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.

  4. 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).

  5. 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

  6. 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.

  7. Chemical and Trajectory Analysis of an Air Mass Plume from Asia

    NASA Astrophysics Data System (ADS)

    Guo, J. J.; Marrero, J. E.; Blake, D. R.

    2014-12-01

    Tracking the source of pollution events is important in understanding the transport of pollution plumes and impact on areas far from the source. Previous studies have shown that the rising contribution of Asian air pollution to the US has increased the number of days that pollution events exceed National Ambient Air Quality Standards (NAAQS). Whole air samples collected over the Edwards Air Force Base during a June 2014 NASA Student Airborne Research Program (SARP) flight exhibited enhancements in the concentrations of several compounds between 23-32 thousand feet. Chemical tracer analysis of these high altitude samples reveal that the air does not correspond to California emitted air. Chemical signatures in the plume, including high levels of OCS, chloroform, and methyl chloride, and low levels of methyl bromide, indicate that the plume was most heavily influence by coal combustion with contributions from biomass burning events from Asia. Low concentrations of ethene at the high altitude despite enhanced concentrations of ethane and ethyne suggest that this plume was aged. Further analysis of the plume using meteorological wind trajectories reveal that the plume had originated in China approximately 4-5 days prior. This is faster than results from previous studies that had found a Spring transport time of approximately 6 days.

  8. 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.

  9. A Lagrangian analysis of ice-supersaturated air over the North Atlantic

    NASA Astrophysics Data System (ADS)

    Irvine, E. A.; Hoskins, B. J.; Shine, K. P.

    2014-01-01

    Understanding the nature of air parcels that exhibit ice supersaturation is important because they are the regions of potential formation of both cirrus and aircraft contrails, which affect the radiation balance. Ice-supersaturated air parcels in the upper troposphere and lower stratosphere over the North Atlantic are investigated using Lagrangian trajectories. The trajectory calculations use European Centre for Medium-Range Weather Forecasts Interim reanalysis data for three winter and three summer seasons, resulting in approximately 200,000 trajectories with ice supersaturation for each season. For both summer and winter, the median duration of ice supersaturation along a trajectory is less than 6 h. Five percent of air which becomes ice supersaturated in the troposphere and 23% of air which becomes ice supersaturated in the stratosphere will remain ice supersaturated for at least 24 h. Weighting the ice-supersaturation duration with the observed frequency indicates the likely overall importance of the longer duration ice-supersaturated trajectories. Ice-supersaturated air parcels typically experience a decrease in moisture content while ice supersaturated, suggesting that cirrus clouds eventually form in the majority of such air. A comparison is made between short-lived (less than 24 h) and long-lived (greater than 24 h) ice-supersaturated air flows. For both air flows, ice supersaturation occurs around the northernmost part of the trajectory. Short-lived ice-supersaturated air flows show no significant differences in speed or direction of movement to subsaturated air parcels. However, long-lived ice-supersaturated air occurs in slower-moving air flows, which implies that they are not associated with the fastest moving air through a jet stream.

  10. 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

  11. 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.

  12. Fast descent routes from within or near the stratosphere to the surface at Fukuoka, Japan, studied using 7Be measurements and trajectory calculations

    NASA Astrophysics Data System (ADS)

    Itoh, Hisanori; Narazaki, Yukinori

    2016-05-01

    By using high concentrations of 7Be as an indicator, we clarify fast descent routes from within or near the stratosphere to Earth's surface, with the study site being in Fukuoka, Japan. Most routes arise from high latitudes through the following processes. First, the descent associated with a tropopause fold occurs, followed by southward movement with slow descent at the rear side of a strong trough. Because this motion occurs along an isentropic surface, the descending air parcels nearly conserve the potential temperature. As an extension, a strong descent associated with a sharp drop in the isentropic-surface height occurs at the southern edge of the trough; this transports air parcels to low altitudes. This process involves irreversible phenomena such as filamentation and cutoff of potential vorticity. Finally, upon meeting appropriate near-surface disturbances, parcels at low altitudes are transported to Earth's surface.In some cases, parcels descend within midlatitudes. In such routes, because the potential temperature is much higher at high altitudes than at low altitudes, descent with conservation of the potential temperature is impossible, and the potential temperature decreases along the trajectories through mixing.The prevalence of the high-latitude route is explained as follows. In the midlatitude route, because parcels at high and relatively low altitudes mix, the high concentrations of 7Be included in high-altitude parcels are difficult to maintain. Therefore, for parcels to arrive at low altitudes in the midlatitude while maintaining high concentrations of 7Be, i.e., conserving the potential temperature, their area of origin should be high altitudes in high latitudes where the potential temperature is almost the same as that in the arrival area.

    In spring, tropopause folds are frequent in high latitudes, disturbances in the southward transport of parcels are strong, and disturbances occur by which parcels descend to the surface. Therefore

  13. 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.

  14. 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.

  15. 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...

  16. 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. PMID:23912073

  17. Trajectory modeling of emissions from lower stratospheric aircraft

    NASA Astrophysics Data System (ADS)

    Sparling, Lynn C.; Schoeberl, Mark R.; Douglass, Anne R.; Weaver, Clark J.; Newman, Paul A.; Lait, Leslie R.

    1995-01-01

    A series of isentropic trajectory calculations has been performed for emissions by stratospheric aircraft moving across the northern midlatitude oceanic flight corridors. Emission of exhaust is simulated by the daily initialization of air parcels along a flight path on the 500 K isentropic surface. Parcels are tracked during the first three weeks of each January from 1980 to 1994 in order to determine the interannual variability in the spatial distribution of the exhaust and the likelihood of exposure to cold temperatures. Few parcels emitted along these flight paths at this time of year were found to have experienced nitric acid trihydrate (NAT) formation temperatures, except for the particularly cold Januarys 1986, 1987, and 1992. We also find that large zonal fluctuations in the distribution of the emissions are typical for this time of year and are strongly dependent on flight path. An extended 6-month (January-June) run in which parcels were released daily along the New York-London route shows that emissions in the flight corridor increase at a time-averaged rate which is nearly twice the rate at which the zonal average increases. In addition, local fluctuations of pollutant density can be several times higher than the zonal average and can persist for several weeks. A study of seasonal variability also shows a rapid buildup of emissions during the summer months. These elevated emission levels must be considered in the interpretation of environmental impact assessments based on two-dimensional transport models.

  18. Trajectory modeling of emissions from lower stratospheric aircraft

    SciTech Connect

    Sparling, L.C.; Lait, L.R.; Weaver, C.J.

    1995-01-20

    A series of isentropic trajectory calculations has been performed for emissions by stratospheric aircraft moving across the northern midlatitude oceanic flight corridors. Emission of exhaust is simulated by the daily initialization of air parcels along a flight path on the 500 K isentropic surface. Parcels are tracked during the first three weeks of each January from 1980 to 1994 in order to determine the interannual variability in the spatial distribution of the exhaust and the liklihood of exposure to cold temperatures. Few parcels emitted along these flights paths at this time of year were found to have experienced nitric acid trihydrate (NAT) formation temperatures, except for the particularly cold Januarys 1986, 1987, and 1992. The authors also find that large zonal fluctuations in the distribution of the emissions are typical for this time of year and are strongly dependent on flight path. An extended 6-month (January-June) run in which parcels were released daily along the New York-London route shows that emissions in the flight corridor increase at a time-averaged rate which is nearly twice the rate at which the zonal average increases. In addition, local fluctuations of pollutant density can be several times higher than the zonal average and can persist for several weeks. A study of seasonal variability also shows a rapid buildup of emissions during the summer months. These elevated emission levels must be considered in the interpretation of environmental impact assessments based on two-dimensional transport models. 31 refs., 16 figs.

  19. Identification of aerosol types over an urban site based on air-mass trajectory classification

    NASA Astrophysics Data System (ADS)

    Pawar, G. V.; Devara, P. C. S.; Aher, G. R.

    2015-10-01

    Columnar aerosol properties retrieved from MICROTOPS II Sun Photometer measurements during 2010-2013 over Pune (18°32‧N; 73°49‧E, 559 m amsl), a tropical urban station in India, are analyzed to identify aerosol types in the atmospheric column. Identification/classification is carried out on the basis of dominant airflow patterns, and the method of discrimination of aerosol types on the basis of relation between aerosol optical depth (AOD500 nm) and Ångström exponent (AE, α). Five potential advection pathways viz., NW/N, SW/S, N, SE/E and L have been identified over the observing site by employing the NOAA-HYSPLIT air mass back trajectory analysis. Based on AE against AOD500 nm scatter plot and advection pathways followed five major aerosol types viz., continental average (CA), marine continental average (MCA), urban/industrial and biomass burning (UB), desert dust (DD) and indeterminate or mixed type (MT) have been identified. In winter, sector SE/E, a representative of air masses traversed over Bay of Bengal and Eastern continental Indian region has relatively small AOD (τpλ = 0.43 ± 0.13) and high AE (α = 1.19 ± 0.15). These values imply the presence of accumulation/sub-micron size anthropogenic aerosols. During pre-monsoon, aerosols from the NW/N sector have high AOD (τpλ = 0.61 ± 0.21), and low AE (α = 0.54 ± 0.14) indicating an increase in the loading of coarse-mode particles over Pune. Dominance of UB type in winter season for all the years (i.e. 2010-2013) may be attributed to both local/transported aerosols. During pre-monsoon seasons, MT is the dominant aerosol type followed by UB and DD, while the background aerosols are insignificant.

  20. 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.

  1. An investigation of particle trajectories and melting in an air plasma sprayed zirconia

    SciTech Connect

    Neiser, R.A.; Roemer, T.J.

    1996-12-31

    The partially stabilized zirconia powders used to plasma spray thermal barrier coatings typically exhibit broad particle-size distributions. There are conflicting reports in the literature about the extent of injection-induced particle-sizing effects in air plasma-sprayed materials. If significant spatial separation of finer and coarser particles in the jet occurs, then one would expect it to play an important role in determining the microstructure and properties of deposits made from powders containing a wide range of particle sizes. This paper presents the results of a study in which a commercially available zirconia powder was fractionated into fine, medium, and coarse cuts and sprayed at the same torch conditions used for the ensemble powder. Diagnostic measurements of particle surface temperature, velocity, and number-density distributions in the plume for each size-cut and for the ensemble powder are reported. Deposits produced by traversing the torch back and forth to produce a raised bead were examined metallographically to study their shape and location with respect to the torch centerline and to look at their internal microstructure. The results show that, for the torch conditions used in this study, the fine, medium, and coarse size-cuts all followed the same mean trajectory. No measureable particle segregation effects were observed. Considerable differences in coatings microstructure were observed. These differences can be explained by the different particle properties measured in the plume.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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...

  9. 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.

  10. Parcellating connectivity in spatial maps.

    PubMed

    Baldassano, Christopher; 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.

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

    NASA Astrophysics Data System (ADS)

    Hattis, Philip D.; Malchow, Harvey L.

    1992-12-01

    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.

  12. 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.

  13. 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.

  14. 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.

  15. An air-mass trajectory study of the transport of radioactivity from Fukushima to Thessaloniki, Greece and Milan, Italy

    NASA Astrophysics Data System (ADS)

    Ioannidou, A.; Giannakaki, E.; Manolopoulou, M.; Stoulos, S.; Vagena, E.; Papastefanou, C.; Gini, L.; Manenti, S.; Groppi, F.

    2013-08-01

    Analyses of 131I, 137Cs and 134Cs in airborne aerosols were carried out in daily samples at two different sites of investigation: Thessaloniki, Greece (40° N) and Milan, Italy (45° N) after the Fukushima accident during the period of March-April, 2011. The radionuclide concentrations were determined and studied as a function of time. The 131I concentration in air over Milan and Thessaloniki peaked on April 3-4, 2011, with observed activities 467 μBq m-3 and 497 μBq m-3, respectively. The 134Cs/137Cs activity ratio values in air were around 1 in both regions, related to the burn-up history of the damaged nuclear fuel of the destroyed nuclear reactor. The high 131I/137Cs ratio, observed during the first days after the accident, followed by lower values during the following days, reflects not only the initial release ratio but also the different volatility, attachment and removal of the two isotopes during transportation due to their different physico-chemical properties. No artificial radionuclides could be detected in air after April 28, 2011 in both regions of investigation. The different maxima of airborne 131I and 134,137Cs in these two regions were related to long-range air mass transport from Japan, across the Pacific and to Central Europe. Analysis of backward trajectories was used to confirm the arrival of artificial radionuclides following atmospheric transport and processing. HYSPLIT backward trajectories were applied for the interpretation of activity variations of measured radionuclides.

  16. 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. PMID:20529718

  17. Rainwater monocarboxylic and dicarboxylic acid concentrations in southeastern North Carolina, USA, as a function of air-mass back-trajectory

    NASA Astrophysics Data System (ADS)

    Brooks Avery, G.; Kieber, Robert J.; Witt, Melanie; Willey, Joan D.

    Eight organic acids were measured in 111 rain events occurring between September 1996 and May 1998 in Wilmington, North Carolina. Formic and acetic acids were the most abundant comprising approximately 75% of the total molar quantity of organic acids. The annual volume-weighted concentrations of organic acids in order of decreasing abundance in rainwater was formic (9.9 μM), acetic (7.3 μM), oxalic (1.8 μM), lactic (1.3 μM), succinic (1.0 μM), malonic (0.7 μM), pyruvic (0.3 μM), and maleic (0.1 μM), with methanesulfonic and glyoxylic acids usually below their detection limit. Growing season back-trajectory data provided strong evidence that terrestrial organic acid sources dominated over marine sources. Air mass back-trajectory analysis indicated that during the growing season air mass origin had a consistent impact on concentrations of rainwater organic acids. Rain with continental back-trajectories coming from the west had the highest concentrations of organic acids while two predominately marine back-trajectories had the lowest concentrations. Concentrations of organic acids in non-growing season rain did not display a consistent pattern indicating variability in sources. Seasonality of individual organic acids for specific back-trajectories was most pronounced in terrestrial back-trajectories and least in the marine back-trajectories indicating that seasonality in rainwater organic acid concentrations is driven by variations in terrestrial sources. Formic to acetic acid ratios (F:A), previously an indicator of terrestrial versus marine sources of these organic acids, were similar for all back-trajectories reflecting anthropogenic impacts on F:A locally and regionally. The ratios of malonic to succinic acids (M:S), also an indicator of sources for these acids, indicated direct anthropogenic sources for terrestrial back-trajectories and secondary processes for marine back-trajectories.

  18. 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.

  19. 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 &...

  20. 77 FR 37078 - Product Change-Parcel Select and Parcel Return Service Negotiated Service Agreement

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-20

    ... From the Federal Register Online via the Government Publishing Office POSTAL SERVICE Product Change--Parcel Select and 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 &...

  1. 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.

  2. 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)

  3. Relationships between convective storms and their environment in AVE IV determined from a three-dimensional subsynoptic-scale, trajectory model

    NASA Technical Reports Server (NTRS)

    Wilson, G. S.

    1977-01-01

    The paper describes interrelationships between synoptic-scale and convective-scale systems obtained by following individual air parcels as they traveled within the convective storm environment of AVE IV. (NASA's fourth Atmospheric Variability Experiment, AVE IV, was a 36-hour study in April 1975 of the atmospheric variability and structure in regions of convective storms.) A three-dimensional trajectory model was used to calculate parcel paths, and manually digitized radar was employed to locate convective activity of various intensities and to determine those trajectories that traversed the storm environment. Spatial and temporal interrelationships are demonstrated by reference to selected time periods of AVE IV which contain the development and movement of the squall line in which the Neosho tornado was created.

  4. PEM-West trajectory climatology and photochemical model sensitivity study prepared using retrospective meteorological data

    NASA Technical Reports Server (NTRS)

    Merrill, John T.; Rodriguez, Jose M.

    1991-01-01

    Trajectory and photochemical model calculations based on retrospective meteorological data for the operations areas of the NASA Pacific Exploratory Mission (PEM)-West mission are summarized. The trajectory climatology discussed here is intended to provide guidance for flight planning and initial data interpretation during the field phase of the expedition by indicating the most probable path air parcels are likely to take to reach various points in the area. The photochemical model calculations which are discussed indicate the sensitivity of the chemical environment to various initial chemical concentrations and to conditions along the trajectory. In the post-expedition analysis these calculations will be used to provide a climatological context for the meteorological conditions which are encountered in the field.

  5. Simple Models for Airport Delays During Transition to a Trajectory-Based Air Traffic System

    NASA Astrophysics Data System (ADS)

    Brooker, Peter

    It is now widely recognised that a paradigm shift in air traffic control concepts is needed. This requires state-of-the-art innovative technologies, making much better use of the information in the air traffic management (ATM) system. These paradigm shifts go under the names of NextGen in the USA and SESAR in Europe, which inter alia will make dramatic changes to the nature of airport operations. A vital part of moving from an existing system to a new paradigm is the operational implications of the transition process. There would be business incentives for early aircraft fitment, it is generally safer to introduce new technologies gradually, and researchers are already proposing potential transition steps to the new system. Simple queuing theory models are used to establish rough quantitative estimates of the impact of the transition to a more efficient time-based navigational and ATM system. Such models are approximate, but they do offer insight into the broad implications of system change and its significant features. 4D-equipped aircraft in essence have a contract with the airport runway and, in return, they would get priority over any other aircraft waiting for use of the runway. The main operational feature examined here is the queuing delays affecting non-4D-equipped arrivals. These get a reasonable service if the proportion of 4D-equipped aircraft is low, but this can deteriorate markedly for high proportions, and be economically unviable. Preventative measures would be to limit the additional growth of 4D-equipped flights and/or to modify their contracts to provide sufficient space for the non-4D-equipped flights to operate without excessive delays. There is a potential for non-Poisson models, for which there is little in the literature, and for more complex models, e.g. grouping a succession of 4D-equipped aircraft as a batch.

  6. 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.

  7. 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.

  8. 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...

  9. Proposed sale of Parcel A2 of the Oak Ridge Reservation to the City of Oak Ridge, Tennessee

    SciTech Connect

    Not Available

    1992-09-01

    Parcel A encompasses two tracts of land owned by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR). The disposal of land was recommended by a General Services Administration 1981 land utilization survey. On June 21, 1988, 21.3 ha (52.7 acres) of land, Parcel A1, were transferred to the City of Oak Ridge. Parcel Al has since been transferred to the private sector for residential development. The City of Oak Ridge has requested acquisition of Parcel A2 for residential and industrial development. The purpose of the proposed action is to transfer Parcel A2 to the City of Oak Ridge for residential and industrial development. The need for the proposed action is for DOE to respond to the General Services Administration directive to dispose of Parcel A2 and to respond to the request by the City of Oak Ridge for its acquisition and development. The proposed sale of Parcel A2 would have no environmental impacts; however, the subsequent development by the City would affect the existing environment. It is the potential effects of the City's development of Parcel A2 that are addressed by this environmental assessment (EA). Areas of concern include land use, air quality, hydrology and water quality, wetlands and floodplains, ecological resources, and socioeconomic resources.

  10. Proposed sale of Parcel A2 of the Oak Ridge Reservation to the City of Oak Ridge, Tennessee. Environmental asssessment

    SciTech Connect

    Not Available

    1992-09-01

    Parcel A encompasses two tracts of land owned by the US Department of Energy (DOE) on the Oak Ridge Reservation (ORR). The disposal of land was recommended by a General Services Administration 1981 land utilization survey. On June 21, 1988, 21.3 ha (52.7 acres) of land, Parcel A1, were transferred to the City of Oak Ridge. Parcel Al has since been transferred to the private sector for residential development. The City of Oak Ridge has requested acquisition of Parcel A2 for residential and industrial development. The purpose of the proposed action is to transfer Parcel A2 to the City of Oak Ridge for residential and industrial development. The need for the proposed action is for DOE to respond to the General Services Administration directive to dispose of Parcel A2 and to respond to the request by the City of Oak Ridge for its acquisition and development. The proposed sale of Parcel A2 would have no environmental impacts; however, the subsequent development by the City would affect the existing environment. It is the potential effects of the City`s development of Parcel A2 that are addressed by this environmental assessment (EA). Areas of concern include land use, air quality, hydrology and water quality, wetlands and floodplains, ecological resources, and socioeconomic resources.

  11. Simulated Convectively Influenced vs. Lightning Influenced Air: Methods for Calculation and Associated Uncertainties

    NASA Astrophysics Data System (ADS)

    Heath, N.; Freeman, S.; Fuelberg, H. E.

    2014-12-01

    Some atmospheric chemical processes are influenced by the presence of convection and/or lightning. Therefore, it is often important to determine whether a sampled air parcel previously has encountered these influences. This paper describes procedures for making these determinations and provides uncertainties associated with the procedures. Prior locations of the sampled air are obtained by calculating backward trajectories based on 1 h WRF output with 3 domains (horizontal grid spacing of 36, 12, and 4 km). Back trajectories are released along every DC-8 flight track from the recent NASA SEAC4RS campaign (~22,000 trajectories total). If lightning influence is sought, locations of the flashes usually are obtained from ground-based networks such as the National Lightning Detection Network (NLDN). Results show that the user-defined spatial and temporal separation between a trajectory and the flash location greatly influences whether the trajectory is considered lightning influenced. For example, a spatial threshold of 0.5 (0.25) deg lat/lon leads to 69% (60%) of the trajectories being lightning influenced. If model-derived convective influence is sought, a vertical displacement threshold corresponding to w≥1 m s-1 is used to identify convectively influenced parcels. Remarkably, the model-derived method using the 4 km WRF output leads to only 5% (compared to ~60% from lightning) of the trajectories being convectively influenced. Additionally, the horizontal grid spacing (36 km vs. 4 km) exerts a major influence on the paths of the trajectories. The overriding conclusion is that very different results are obtained depending on whether simulated convectively influenced or lightning influenced air is being sought. Also, once this choice is made, the resolution of the model and the time/space thresholds that are chosen will have a major impact on the number of trajectories that are determined to be influenced. This paper will provide guidance on these choices.

  12. GCSS Cirrus Parcel Model Comparison Project

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

    assumptions that can only be justified by further laboratory data. 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 (20-100 cm/s) 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 nucleation 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 ice number concentration and ice crystal diffusional growth rate, which is sensitive to the deposition coefficient when ice particles are small, partially controls the peak nucleation 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 nucleated (heterogeneous) ice crystals limits 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.

  13. 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.

  14. A Variable Trajectory Plume Segment Model to Assess Ground-Level Air Concentrations and Depositions of Routine Effluent Releases from Nuclear Power Facilities.

    1986-05-27

    Version: 00 MESODIF-II, which embodies a variable trajectory plume segment atmospheric transport model, is designed to predict normalized air concentrations and deposition of radioactive, but otherwise non-reactive, effluents released from one or two levels over the same position in an xy-plane. In such a model, calculated particle trajectories vary as synoptic scale wind varies. At all sampling times, the particles are connected to form a segmented plume centerline. The lateral and vertical dimensions of themore » plume are determined by a parameterization of turbulence scale diffusion. The impetus for the development of this model arose from the need of the U. S. Nuclear Regulatory Commission to assess radiological effects resulting from routine nuclear power reactor operations, as outlined in U. S. Nuclear Regulatory Guide 1.111.« less

  15. A Variable Trajectory Plume Segment Model to Assess Ground-Level Air Concentrations and Depositions of Routine Effluent Releases from Nuclear Power Facilities.

    SciTech Connect

    1986-05-27

    Version: 00 MESODIF-II, which embodies a variable trajectory plume segment atmospheric transport model, is designed to predict normalized air concentrations and deposition of radioactive, but otherwise non-reactive, effluents released from one or two levels over the same position in an xy-plane. In such a model, calculated particle trajectories vary as synoptic scale wind varies. At all sampling times, the particles are connected to form a segmented plume centerline. The lateral and vertical dimensions of the plume are determined by a parameterization of turbulence scale diffusion. The impetus for the development of this model arose from the need of the U. S. Nuclear Regulatory Commission to assess radiological effects resulting from routine nuclear power reactor operations, as outlined in U. S. Nuclear Regulatory Guide 1.111.

  16. Spontaneous change in trajectory patterns of a self-propelled oil droplet at the air-surfactant solution interface

    NASA Astrophysics Data System (ADS)

    Tanaka, Shinpei; Sogabe, Yoshimi; Nakata, Satoshi

    2015-03-01

    Trajectory-pattern formation of a self-propelled oil droplet floating on the surface of a surfactant solution in a circular dish is studied both experimentally and by simulation. The Marangoni effect induced by the dissolution of oil in the solution drives the droplet's motion. The trajectories spontaneously organize into several patterns including circular, knot-forming, back-and-forth, and irregular ones. They are either global patterns, whose center corresponds to the dish center, or other local patterns. Our simple model consisting of three forces, the driving force, the viscous resistance, and the repulsion from the boundary, successfully reproduces the global trajectory patterns including the power spectrum of the droplet speed.

  17. Optimal combination of multiple cortical surface parcellations

    NASA Astrophysics Data System (ADS)

    Hu, Xintao; Guo, Lei; Li, Gang; Li, Kaiming; Liu, Tianming

    2010-03-01

    A variety of methodologies have been developed for the parcellation of human cortical surface into sulcal or gyral regions due to its importance in structural and functional mapping of the human brain. However, characterizing the performance of surface parcellation methods and the estimation of ground truth of segmentation are still open problems. In this paper, we present an algorithm for simultaneous truth and performance estimation of various approaches for human cortical surface parcellation. The probabilistic true segmentation is estimated as a weighted combination of the segmentations resulted from multiple methods. Afterward, an Expectation-Maximization (EM) algorithm is used to optimize the weighting depending on the estimated performance level of each method. Furthermore, a spatial homogeneity constraint modeled by the Hidden Markov Random Field (HMRF) theory is incorporated to refine the estimated true segmentation into a spatially homogenous decision. The proposed method has been evaluated using both synthetic and real data. The experimental results demonstrate the validity of the method proposed in this paper. Also, it has been used to generate reference sulci regions to perform a comparison study of three methods for cortical surface parcellation.

  18. Mathematical Model of Evolution of Brain Parcellation.

    PubMed

    Ferrante, Daniel D; Wei, Yi; Koulakov, Alexei A

    2016-01-01

    We study the distribution of brain and cortical area sizes [parcellation units (PUs)] obtained for three species: mouse, macaque, and human. We find that the distribution of PU sizes is close to lognormal. We propose the mathematical model of evolution of brain parcellation based on iterative fragmentation and specialization. In this model, each existing PU has a probability to be split that depends on PU size only. This model suggests that the same evolutionary process may have led to brain parcellation in these three species. Within our model, region-to-region (macro) connectivity is given by the outer product form. We show that most experimental data on non-zero macaque cortex macroscopic-level connections can be explained by the outer product power-law form suggested by our model (62% for area V1). We propose a multiplicative Hebbian learning rule for the macroconnectome that could yield the correct scaling of connection strengths between areas. We thus propose an evolutionary model that may have contributed to both brain parcellation and mesoscopic level connectivity in mammals. PMID:27378859

  19. Mathematical Model of Evolution of Brain Parcellation

    PubMed Central

    Ferrante, Daniel D.; Wei, Yi; Koulakov, Alexei A.

    2016-01-01

    We study the distribution of brain and cortical area sizes [parcellation units (PUs)] obtained for three species: mouse, macaque, and human. We find that the distribution of PU sizes is close to lognormal. We propose the mathematical model of evolution of brain parcellation based on iterative fragmentation and specialization. In this model, each existing PU has a probability to be split that depends on PU size only. This model suggests that the same evolutionary process may have led to brain parcellation in these three species. Within our model, region-to-region (macro) connectivity is given by the outer product form. We show that most experimental data on non-zero macaque cortex macroscopic-level connections can be explained by the outer product power-law form suggested by our model (62% for area V1). We propose a multiplicative Hebbian learning rule for the macroconnectome that could yield the correct scaling of connection strengths between areas. We thus propose an evolutionary model that may have contributed to both brain parcellation and mesoscopic level connectivity in mammals. PMID:27378859

  20. 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.

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

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15... From Hawaii and the Territories § 318.13-15 Parcel post inspection. Inspectors are authorized to inspect, with the cooperation of the U.S. Postal Service, parcel post packages placed in the mails...

  2. 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.

  3. Back-trajectory modelling and DNA-based species-specific detection methods allow tracking of fungal spore transport in air masses.

    PubMed

    Grinn-Gofroń, Agnieszka; Sadyś, Magdalena; Kaczmarek, Joanna; Bednarz, Aleksandra; Pawłowska, Sylwia; Jedryczka, Malgorzata

    2016-11-15

    Recent advances in molecular detection of living organisms facilitate the introduction of novel methods to studies of the transport of fungal spores over large distances. Monitoring the migration of airborne fungi using microscope based spore identification is limited when different species produce very similar spores. In our study, DNA-based monitoring with the use of species-specific probes allowed us to track the aerial movements of two important fungal pathogens of oilseed rape (Brassica napus L.), i.e., Leptosphaeria maculans and Leptosphaeria biglobosa, which have identical spore shape and size. The fungi were identified using dual-labelled fluorescent probes that were targeted to a β-tubulin gene fragment of either Leptosphaeria species. Spore identification by Real-Time PCR techniques capable of detecting minute amounts of DNA of selected fungal species was combined with back-trajectory analysis, allowing the tracking of past movements of air masses using the Hybrid Single Particle Lagrangian Integrated Trajectory model. Over a study period spanning the previous decade (2006-2015) we investigated two specific events relating to the long distance transport of Leptosphaeria spp. spores to Szczecin in North-West Poland. Based on the above mentioned methods and the results obtained with the additional spore sampler located in nearby Szczecin, and operating at the ground level in an oilseed rape field, we have demonstrated that on both occasions the L. biglobosa spores originated from the Jutland Peninsula. This is the first successful attempt to combine analysis of back-trajectories of air masses with DNA-based identification of economically important pathogens of oilseed rape in Europe. In our studies, the timing of L. biglobosa ascospore dispersal in the air was unlikely to result in the infection of winter oilseed rape grown as a crop plant. However, the fungus could infect other host plants, such as vegetable brassicas, cruciferous weeds, spring rapeseed

  4. Back-trajectory modelling and DNA-based species-specific detection methods allow tracking of fungal spore transport in air masses.

    PubMed

    Grinn-Gofroń, Agnieszka; Sadyś, Magdalena; Kaczmarek, Joanna; Bednarz, Aleksandra; Pawłowska, Sylwia; Jedryczka, Malgorzata

    2016-11-15

    Recent advances in molecular detection of living organisms facilitate the introduction of novel methods to studies of the transport of fungal spores over large distances. Monitoring the migration of airborne fungi using microscope based spore identification is limited when different species produce very similar spores. In our study, DNA-based monitoring with the use of species-specific probes allowed us to track the aerial movements of two important fungal pathogens of oilseed rape (Brassica napus L.), i.e., Leptosphaeria maculans and Leptosphaeria biglobosa, which have identical spore shape and size. The fungi were identified using dual-labelled fluorescent probes that were targeted to a β-tubulin gene fragment of either Leptosphaeria species. Spore identification by Real-Time PCR techniques capable of detecting minute amounts of DNA of selected fungal species was combined with back-trajectory analysis, allowing the tracking of past movements of air masses using the Hybrid Single Particle Lagrangian Integrated Trajectory model. Over a study period spanning the previous decade (2006-2015) we investigated two specific events relating to the long distance transport of Leptosphaeria spp. spores to Szczecin in North-West Poland. Based on the above mentioned methods and the results obtained with the additional spore sampler located in nearby Szczecin, and operating at the ground level in an oilseed rape field, we have demonstrated that on both occasions the L. biglobosa spores originated from the Jutland Peninsula. This is the first successful attempt to combine analysis of back-trajectories of air masses with DNA-based identification of economically important pathogens of oilseed rape in Europe. In our studies, the timing of L. biglobosa ascospore dispersal in the air was unlikely to result in the infection of winter oilseed rape grown as a crop plant. However, the fungus could infect other host plants, such as vegetable brassicas, cruciferous weeds, spring rapeseed

  5. 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.

  6. Cluster Analysis of the Trajectories for Forecasted Transport of Air Pollutants using WRF and HYSPLIT Models over Istanbul for January and July, 2009

    NASA Astrophysics Data System (ADS)

    Acar, M.; Balli, C.; Caglar, F.; Tan, E.; Onol, B.; Karan, H.; Unal, Y.

    2012-04-01

    The objective of this study is to determine the risk areas which would be under the influence of particulates and gases released from a hypothetical source in Istanbul and transported by dominant atmospheric flows for months of January and July. Both January and July wind simulations are performed for the year of 2009 using the WRF model to distinguish the seasonal variations. For the initial and boundary conditions, ECMWF forecast data set is used and the results are compared to the ECMWF ERA-Interim data. Three nested domains are used over the Northwestern part of Turkey, Istanbul has been chosen as the centre point of the nested domains, which have 420x270, 385x352, and 400x310 grid points for the 9km, 3km, and 1km resolutions, respectively, and all domains have 45 vertical levels. WSM6 microphysics and YSU planetary boundary layer schemes are used for all domains. Grell-Devenyi cumulus parameterization scheme is used for the mother domain. 30s horizontal grid spaced MODIS land use data is preferred instead of USGS land use data. 24 hours forecasts are calculated starting from both the 00 UTC and 12 UTC for all days of January and July. In this study, HYSPLIT 24 hourly forward trajectory analyses are performed by using WRF results for thirteen height levels: 10m, 50m, 100m, 200m, 300m, 400m, 500m, 600m, 800m, 1000m, 1500m, 2000m, and 3000m. 5 clusters are determined using Total Spatial Variance (TSV) method for each January and July trajectory analyses. Only the trajectories for 10m, 50m, 500m, and 2000m levels are clustered in order to decide the predominant flow regime for each month. Moreover, the same cluster analyses are achieved for the WRF simulations for the mother domain, ECMWF operational data, and ERA-Interim to discuss the model performance versus observational data based on 5 cluster members. Comparisons of wind speeds for Istanbul between observations (surface/upper air), and simulations (ECMWF Interim/ECMWF forecast/WRF) revealed that both

  7. 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.

  8. Trajectory and Microphysical Modeling of TTL Water

    NASA Astrophysics Data System (ADS)

    Ueyama, R.; Jensen, E. J.; Pfister, L.

    2014-12-01

    Processes that influence H2O concentrations in the Tropical Tropopause Layer (TTL) and consequently regulate stratospheric humidity are investigated in simulations of clouds along backward trajectories of TTL parcels initialized with H2O measurements from Microwave Limb Sounder (MLS). Trajectories are calculated using offline calculations of seasonal mean radiative heating rates in the tropics merged with MERRA extratropical heating rates and ERA-Interim temperature and wind data that have been modified to enhance wave-driven variability in the TTL. We also examine the impact of convective influence along parcel trajectories on cloud formation and dehydration. The distribution of 100 hPa H2O mixing ratios simulated on the final day of the trajectories in boreal winter 2006-07 resembles that of MLS with distinct minima over the western and eastern tropical Pacific, but exhibits an overall dry bias of approximately 20%. Averaged over the tropics, subgrid-scale waves dehydrate the 100 hPa level by ~0.5 ppmv, while convection and cloud microphysical processes moisten by ~0.5 and ~0.7 ppmv, respectively. These three processes combined increase the tropical mean H2O estimate by roughly 20% compared to that based solely on the Lagrangian Dry Point of the trajectories. Possible causes of the model dry bias and TTL cirrus statistics in comparison to those of recent aircraft campaigns will also be discussed.

  9. 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)

  10. Parcellation in Left Lateral Parietal Cortex Is Similar in Adults and Children

    PubMed Central

    Nelson, Steven M.; Cohen, Alexander L.; Power, Jonathan D.; Coalson, Rebecca S.; Miezin, Francis M.; Vogel, Alecia C.; Dubis, Joseph W.; Church, Jessica A.; Petersen, Steven E.; Schlaggar, Bradley L.

    2012-01-01

    A key question in developmental neuroscience involves understanding how and when the cerebral cortex is partitioned into distinct functional areas. The present study used functional connectivity MRI mapping and graph theory to identify putative cortical areas and generate a parcellation scheme of left lateral parietal cortex (LLPC) in 7 to 10-year-old children and adults. Results indicated that a majority of putative LLPC areas could be matched across groups (mean distance between matched areas across age: 3.15 mm). Furthermore, the boundaries of children's putative LLPC areas respected the boundaries generated from the adults' parcellation scheme for a majority of children's areas (13/15). Consistent with prior research, matched LLPC areas showed age-related differences in functional connectivity strength with other brain regions. These results suggest that LLPC cortical parcellation and functional connectivity mature along different developmental trajectories, with adult-like boundaries between LLPC areas established in school-age children prior to adult-like functional connectivity. PMID:21810781

  11. Gyral parcellation of cortical surfaces via coupled flow field tracking

    NASA Astrophysics Data System (ADS)

    Li, Gang; Guo, Lei; Li, Kaiming; Nie, Jingxin; Liu, Tianming

    2010-03-01

    This paper presents a novel method for parcellation of the cortical surface of human brain into gyral based regions via coupled flow field tracking. The proposed method consists of two major steps. First, the cortical surface is automatically parcellated into sulcal based regions using several procedures: estimating principal curvatures and principal directions; applying the hidden Markov random field and the Expectation-Maximization (HMRF-EM) framework for sulcal region segmentation based on the maximum principal curvature; diffusing the maximum principal direction field in order to propagate reliable and informative principal directions at gyral crests and sulcal bottoms to other flat cortical regions with noisy principal directions by minimization of an energy function; tracking the flow field towards sulcal bottoms to parcellate the cortical surfaces into sulcal basins. The sulcal parcellation provides a very good initialization for the following steps of gyral parcellation on cortical surfaces. Second, based on the sulcal parcellation results, the cortical surface is further parcellated into gyral based regions using the following procedures: extracting gyral crest segments; dilating gyral crest segments; inverting the principal direction flow field and tracking the flow field towards gyral crests in order to partition the cortical surface into a collection of gyral patches; merging gyral patches to obtain gyral parcellation of the cortical surface. The proposed algorithm pipeline is applied to nine randomly selected cortical surfaces of normal brains and promising results are obtained. The accuracy of the semi-automatic gyral parcellation is comparable to that labeled manually by experts.

  12. 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.

  13. 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.

  14. Manual MRI parcellation of the frontal lobe.

    PubMed

    Ranta, Marin E; Crocetti, Deana; Clauss, Jacqueline A; Kraut, Michael A; Mostofsky, Stewart H; Kaufmann, Walter E

    2009-05-15

    The ability to examine associations between neuropsychiatric conditions and functionally relevant frontal lobe sub-regions is a fundamental goal in neuropsychiatry, but methods for identifying frontal sub-regions in MR (magnetic resonance) images are not well established. Prior published techniques have principally defined gyral regions that do not necessarily correspond to known functional divisions. We present a method in which sulcal-gyral landmarks are used to manually delimit functionally relevant regions within the frontal lobe: primary motor cortex, anterior cingulate, deep white matter, premotor cortex regions (supplementary motor complex (SMC), frontal eye field and lateral premotor cortex) and prefrontal cortex (PFC) regions (medial PFC, dorsolateral PFC (DLPFC), inferior PFC, lateral orbitofrontal cortex (OFC) and medial OFC). Feasibility was tested by applying the protocol to brain MR data from 15 boys with attention-deficit/hyperactivity disorder (ADHD) and 15 typically developing controls, 8-12 years old. Intra- and inter-rater intraclass correlation coefficients were calculated using parcellation volumes from a subset of that group. Inter-rater results for the 22 hemisphere specific sub-regions ranged from 0.724 to 0.997, with all but seven values above 0.9. Boys with ADHD showed significantly smaller left hemisphere SMC and DLPFC volumes after normalization for total cerebral volume. These findings support the method as a reliable and valid technique for parcellating the frontal lobe into functionally relevant sub-regions.

  15. Manual MRI parcellation of the frontal lobe

    PubMed Central

    Richardson, Marin E.; Crocetti, Deana; Clauss, Jacqueline A.; Kraut, Michael A.; Mostofsky, Stewart H.; Kaufmann, Walter E.

    2009-01-01

    The ability to examine associations between neuropsychiatric conditions and functionally relevant frontal lobe sub-regions is a fundamental goal in neuropsychiatry, but methods for identifying frontal sub-regions in MR (magnetic resonance) images are not well established. Prior published techniques have principally defined gyral regions that do not necessarily correspond to known functional divisions. We present a method in which sulcal-gyral landmarks are used to manually delimit functionally relevant regions within the frontal lobe: primary motor cortex, anterior cingulate, deep white matter, premotor cortex regions (supplementary motor complex (SMC), frontal eye field and lateral premotor cortex) and prefrontal cortex (PFC) regions (medial PFC, dorsolateral PFC (DLPFC), inferior PFC, lateral orbitofrontal cortex (OFC) and medial OFC). Feasibility was tested by applying the protocol to brain MR data from 15 boys with ADHD and 15 typically developing controls, 8–12 years old. Intra- and inter-rater intraclass correlation coefficients were calculated using parcellation volumes from a subset of that group. Inter-rater results for the 22 hemisphere specific sub-regions ranged from 0.724 to 0.997, with all but six values above 0.9. Boys with ADHD showed significantly smaller left hemisphere SMC and DLPFC volumes after normalization for total cerebral volume. These findings support the method as a reliable and valid technique for parcellating the frontal lobe into functionally relevant subregions. PMID:19324532

  16. 75 FR 52378 - Transfer of Commercial Standard Mail Parcels to Competitive Product List

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-25

    ... Commission to transfer commercial Standard Mail Parcels from the Mail Classification Schedule's Market... to transfer commercial Standard Mail Parcels from the Mail Classification Schedule's Market Dominant... Commercial Standard Mail Parcels to Competitive Product List AGENCY: Postal Service. TM ACTION:...

  17. 7 CFR 1955.140 - Sale in parcels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false Sale in parcels. 1955.140 Section 1955.140...) PROGRAM REGULATIONS (CONTINUED) PROPERTY MANAGEMENT Disposal of Inventory Property General § 1955.140 Sale... Programs property, may be offered for sale as a whole or subdivided into parcels as determined by the...

  18. 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

  19. 12. John and James Dobson Carpet Mill, West Parcel, site ...

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

    12. John and James Dobson Carpet Mill, West Parcel, site plan-upper right, and surrounding environs, 1884. Hopkins, Griffith Morgan. City Atlas of Philadelphia by Wards, 7 vols., Philadelphia, Pennsylvania: G. M. Hopkins and Co., 1884, Plate 9. - John & James Dobson Carpet Mill (West Parcel), 4041-4055 Ridge Avenue, Philadelphia, Philadelphia County, PA

  20. 48 CFR 242.1404-1 - Parcel post eligible shipments.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Parcel post eligible shipments. 242.1404-1 Section 242.1404-1 Federal Acquisition Regulations System DEFENSE ACQUISITION... Traffic and Transportation Management 242.1404-1 Parcel post eligible shipments. (b)(1) See DoD...

  1. 48 CFR 242.1404-1 - Parcel post eligible shipments.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 3 2011-10-01 2011-10-01 false Parcel post eligible shipments. 242.1404-1 Section 242.1404-1 Federal Acquisition Regulations System DEFENSE ACQUISITION... Traffic and Transportation Management 242.1404-1 Parcel post eligible shipments. (b)(1) See DoD...

  2. 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

  3. Automated MRI parcellation of the frontal lobe

    PubMed Central

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

    2014-01-01

    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) 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. PMID:23897577

  4. [Chemical Characteristics of Particulate Matters and Trajectory Influence on Air Quality in Shanghai During the Heavy Haze Episode in December, 2013].

    PubMed

    Zhou, Min; Qiao, Li-ping; Zhu, Shu-hui; Li, Li; Lou, Sheng-rong; Wang, Hong-li; Tao, Shi-kang; Huang, Cheng; Chen, Chang-hong

    2016-04-15

    Intensive haze shrouded central and eastern parts of China in Dec. 2013. In this study, the mass concentrations of gaseous and particulate pollutants, and also the chemical compositions of fine particulate matters were obtained based on in-situ measurement in Shanghai urban area. The characteristics of PM2.5 were investigated during different pollution episodes, including dust, haze, fog-haze and long-rang transport episodes. The results showed that pollution was most serious during the fog-haze episode, during which the maximum daily mass concentrations of PM10 and PM2.5 reached 536 microg x m(-3) and 411 microg x m(-3), respectively. During the fog-haze episode, the ratio of PM2.5 to PM10 was over 76.7%, suggesting that high humidity enhanced the secondary formation of NO3-, SO4(2-) and NH4+ in PM2.5. Highest concentration of Ca2+ in PM2.5 occurred during the dust episode and the proportion of primary components in PM2.5 increased obviously. Highest concentration of SO2- was observed in PM25 during the long-range transport episode, with a fast growth rate. Meanwhile, the trajectories reaching Shanghai urban area and cluster analysis during different pollution episodes were simulated by HYSPLIT model. Combined with observation data of PM2.5 in Shanghai urban area, chemical characteristics of PM2.5 in different clusters and potential source apportionment of various pollution episodes were also studied in this study. The result revealed that the air trajectories could be grouped into six clusters based on their spatial similarities. Among these clusters, cluster6 which moved fast was associated with clean air. Cluster2 and cluster3 originating from Mongolia region had strong correlations to dust pollution, along with low PM2.5/PM10 ratio and high concentration of Ca2+ in PM2.5. Compared with other clusters, cluster5 and cluster4 with slow moving speed were more favorable for reactions between particulate species and formation of secondary pollutants during transport

  5. [Chemical Characteristics of Particulate Matters and Trajectory Influence on Air Quality in Shanghai During the Heavy Haze Episode in December, 2013].

    PubMed

    Zhou, Min; Qiao, Li-ping; Zhu, Shu-hui; Li, Li; Lou, Sheng-rong; Wang, Hong-li; Tao, Shi-kang; Huang, Cheng; Chen, Chang-hong

    2016-04-15

    Intensive haze shrouded central and eastern parts of China in Dec. 2013. In this study, the mass concentrations of gaseous and particulate pollutants, and also the chemical compositions of fine particulate matters were obtained based on in-situ measurement in Shanghai urban area. The characteristics of PM2.5 were investigated during different pollution episodes, including dust, haze, fog-haze and long-rang transport episodes. The results showed that pollution was most serious during the fog-haze episode, during which the maximum daily mass concentrations of PM10 and PM2.5 reached 536 microg x m(-3) and 411 microg x m(-3), respectively. During the fog-haze episode, the ratio of PM2.5 to PM10 was over 76.7%, suggesting that high humidity enhanced the secondary formation of NO3-, SO4(2-) and NH4+ in PM2.5. Highest concentration of Ca2+ in PM2.5 occurred during the dust episode and the proportion of primary components in PM2.5 increased obviously. Highest concentration of SO2- was observed in PM25 during the long-range transport episode, with a fast growth rate. Meanwhile, the trajectories reaching Shanghai urban area and cluster analysis during different pollution episodes were simulated by HYSPLIT model. Combined with observation data of PM2.5 in Shanghai urban area, chemical characteristics of PM2.5 in different clusters and potential source apportionment of various pollution episodes were also studied in this study. The result revealed that the air trajectories could be grouped into six clusters based on their spatial similarities. Among these clusters, cluster6 which moved fast was associated with clean air. Cluster2 and cluster3 originating from Mongolia region had strong correlations to dust pollution, along with low PM2.5/PM10 ratio and high concentration of Ca2+ in PM2.5. Compared with other clusters, cluster5 and cluster4 with slow moving speed were more favorable for reactions between particulate species and formation of secondary pollutants during transport

  6. New IceTracker Tool Depicts Forward and Backward Arctic Sea Ice Trajectories

    NASA Astrophysics Data System (ADS)

    Pfirman, S. L.; Campbell, G.; Tremblay, B.; Newton, R.; Meier, W.

    2013-12-01

    The IceTracker allows researchers, educators and the public to depict the forward drift trajectories of sea ice, as well as back trajectories showing the path the ice took to the specified location. Users enter in the location and date of an ice parcel - or parcels -- of interest, then select a later or earlier date, depending on whether they want to see the forward or the backward trajectory. The database for the IceTracker contains ice motion vectors based upon a pattern recognition algorithm applied to images of sea ice derived from microwave satellite data. Ice motion vector plots are single day motion estimates. The available database starts November 1978 and runs to the present with ca. 1 month delay. IceTracker output includes both an image of the ice motion path as well as a data file that has quasi-daily date, latitude, longitude, estimated sea ice age, ice drift speed, mean air temperature, and water depth. One can overlay different days on the same plot in different colors for comparing different seasons. This presentation highlights research, education, and outreach applications of the tool. Research applications include estimating the origin and melt location of sediment and contaminants sampled on or in sea ice, assessing potential trajectories oil spilled in ice-infested waters, documenting seasonal and interannual variability in ice drift trajectories from specific locations, defining the typical origins of ice that tend to melt in an area of interest, such as a polynya, and assessing the deviation from drift of polar bear foraging. The IceTracker can also be used in the social sciences, for example recreating Nansen's historic 1893-1896 trans-Arctic drift with the Fram under modern conditions and considering the implications of alternative fates. Educational purposes include teaching students about ice dynamics and interannual variability by setting up team competitions to be the first to reach the North Pole or some other location. Applications

  7. The Cirrus Parcel Model Comparison Project. Phase 1

    NASA Technical Reports Server (NTRS)

    Lin, Ruei-Fong; Starr, D.; DeMott, P.; Cotten, R.; Jensen, E.; Sassen, K.

    2000-01-01

    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 ice number concentration and ice crystal diffusional growth rate, partially controls the peak nucleation rate achieved in an air parcel and the duration of the active nucleation time period.

  8. 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…

  9. 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 ...

  10. 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

  11. Trajectory Simulations of Upper Tropospheric Humidity

    NASA Technical Reports Server (NTRS)

    Dessler, A. E.; Schoeberl, M. R.; Sherwood, S. C.

    1999-01-01

    We present comparisons of simulations of upper tropospheric humidity at 215 and 146 hPa with satellite measurements. Our model uses diabatic trajectories to advect water vapor from an initial condition of 100% relative humidity to the final state. The model does not allow parcels' relative humidity to exceed 100%, and in this way crudely incorporates condensation. We find that this simple model does a good job of simulating the observations. Sensitivity studies suggest that one must have realistic wind velocities in order to accurately simulate the humidity distribution; microphysical parameterizations seem to be less important. Comparisions between simulations using UKMO and NCEP horizontal winds will be discussed.

  12. 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.

  13. Megacity and Air Pollution in the Eastern Mediterranean: Istanbul Case Study

    NASA Astrophysics Data System (ADS)

    Unal, Alper; Kindap, Tayfun; Im, Ulas; Markakis, Kostas; Mihalopoulos, Nikos; Gerasopoulos, Evangelos; Kocak, Mustafa; Mangir, Nizamettin; Kubilay, Nilgun; Kanakidou, Maria

    2010-05-01

    Turkey, with a population of 75 million, is located at the confluence of Europe and Asia. Istanbul is at the hearth of Turkey's fast economic growth. The city has an annual growth of 3.7% and, according to a study conducted by OECD, is ranked 12th among 45 OECD metro-regions. Istanbul generates 27% of Turkey's Gross Domestic Product (GDP); 40% of tax revenues; and 38% of total industrial output (OECD, 2008). As a result, Istanbul is facing a variety of challenging environmental problems affecting more than 15 million people. Observations show that the number of days exceeding the 24-hour limit value of 50 μgm-3 reached 157 in 2008, with a significant increase from previous years. The city is also a hot spot of pollutant emissions for the surrounding Eastern Mediterranean area. As part of the CityZEN project, in order to quantify the contribution of this megacity as a source of air pollution in the Eastern Mediterranean, a climatological trajectory analysis using a regional climate model output (RegCM3) and a high resolution regional modeling study were performed using the Models-3 WRF meteorological and CMAQ air quality models. Trajectory approach was used to identify the effects of Istanbul emissions on other cities in regional scale. A 30-year (1961-1990) period RegCM3 simulations were used to get a meaningful evaluation. The trajectories were computed according to a method described by Pettersen (1956) as a forward trajectory approach in a 27-km grid resolution. An air parcel was released once every 6h and a total of 42,368 air parcels (trajectories) were released during these 30 years. Long-term meteorological observations in Istanbul show northeasterly and southwesterly prevailing winds over the city. According to these prevailing winds, the distributions of trajectories were mainly observed from the north and south directions of the city. In order to run an air quality model, anthropogenic emission inventory was compiled from a number of different sources

  14. Loneliness trajectories.

    PubMed

    van Dulmen, Manfred H M; Goossens, Luc

    2013-12-01

    This special section brings together five studies using group-based modeling to capture developmental trajectories of loneliness from age 7 through age 20. Together, the findings from these studies provide further evidence that developmental trajectories of loneliness are likely not best understood at a continuum but reflect distinct subpopulations that differ both where they start out and how they change over time in terms of mean levels of loneliness. Furthermore, adolescents who show chronically high loneliness or increasing loneliness over time exhibit poorer psychological and physical health, including greater incidence of depressive symptoms and more frequent suicide attempts. The findings from these studies also suggest that individuals experiencing increases in loneliness with age fare worse as well in terms of both physical and psychological health.

  15. 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.

  16. Earthquake Hazard Class Mapping by Parcel in Las Vegas Valley

    NASA Astrophysics Data System (ADS)

    Pancha, A.; Pullammanappallil, S.; Louie, J. N.; Hellmer, W. K.

    2011-12-01

    Clark County, Nevada completed the very first effort in the United States to map earthquake hazard class systematically through an entire urban area. The map is used in development and disaster response planning, in addition to its direct use for building code implementation and enforcement. The County contracted with the Nevada System of Higher Education to classify about 500 square miles including urban Las Vegas Valley, and exurban areas considered for future development. The Parcel Map includes over 10,000 surface-wave array measurements accomplished over three years using Optim's SeisOpt° ReMi measurement and processing techniques adapted for large scale data. These array measurements classify individual parcels on the NEHRP hazard scale. Parallel "blind" tests were conducted at 93 randomly selected sites. The rms difference between the Vs30 values yielded by the blind data and analyses and the Parcel Map analyses is 4.92%. Only six of the blind-test sites showed a difference with a magnitude greater than 10%. We describe a "C+" Class for sites with Class B average velocities but soft surface soil. The measured Parcel Map shows a clearly definable C+ to C boundary on the west side of the Valley. The C to D boundary is much more complex. Using the parcel map in computing shaking in the Valley for scenario earthquakes is crucial for obtaining realistic predictions of ground motions.

  17. Space trajectories

    NASA Astrophysics Data System (ADS)

    Bertachinidealmeidaprado, Antonio Fernando

    The objective of this study is to present a description of the models and methods used to calculate the optimum space trajectories, from the point of view of the smallest fuel consumption that could be used to transfer a space vehicle between two given orbits. Several options for the shaping of the dynamics, the actuators' action and optimal methods are described. Classic methods (Hohmann's transfer, bi-elliptical, etc.) and modern methods (involving gravitational capture and gravity assisted maneuvers) are stated briefly, and several references are mentioned to supply more detail.

  18. Trajectory Hunting As A Powerful Technique To Validate Multi-platform Measurements

    NASA Astrophysics Data System (ADS)

    Danilin, M.; Ko, M.; Froidevaux, L.; Santee, M.; Lyjak, L.; Bevilacqua, R.; Zawodny, J.; Sasano, Y.; Irie, H.; Russell, J., III

    Goal of this presentation is to show that trajectory hunting is a powerful technique for validation satellite multi-platform measurements. Currently, traditional correlative analysis (TCA), which finds matched profiles for a chosen match criterion and com- pares their averaged values, is widely used for validation of the new satellite mea- surements. Trajectory hunting technique (THT) launches backward and forward tra- jectories from the locations of measurements and finds air parcels sampled at least twice during the course of several days. Thus, TCA results are a subset of the THT results and the THT may serve as a statistical reinforcer for the TCA. As an example, we consider the October-November 1996 period and compare the latest versions of ozone measurements made by Microwave Limb Sounder (MLS), Halogen Occulata- tion Experiment (HALOE), Polar Ozone and Aerosol Measurement (POAM-II), Im- proved Limb Atmospheric Spectrometer (ILAS), and Stratospheric Aerosol and Gas Experiment (SAGE-II) in the southern hemisphere. Several consistency tests (e.g., self-hunting, reversibility) and estimate of the photochemical effects are performed for the THT. We show that total THT-related uncertainties are of order 3-5between the TCA and THT results are found for each pair of instruments. Summarizing, ozone measurements from these five instruments agree to better than 0.4 (0.2) ppmv below (above) 30 km. We believe that the THT is a very attractive technique for validation new European satellites.

  19. 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.

  20. 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...

  1. 76 FR 11297 - New Regional Ground Service for Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-01

    ...: The Commission is noticing a recently-filed Postal Service notice of rate and classification changes affecting Parcel Select. The changes involve a new offering identified as Regional Ground service. This notice informs the public of the filing, addresses preliminary procedural matters, and invites...

  2. 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.

  3. 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

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

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 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...

  5. 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...

  6. 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

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

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Parcel post inspection. 318.13-15 Section 318.13-15 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION... subpart, to examine any such products that are found for insect infestation, and to notify the...

  8. 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. PMID:27437579

  9. 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.

  10. 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…

  11. 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...

  12. 15 CFR 740.12 - Gift parcels and humanitarian donations (GFT).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...—(i) Item limitations—(A) Prohibited items. (1) For Cuba no items listed on the Commerce Control List... in gift parcels. (iii) Frequency. (A) Except for gift parcels of food to Cuba, not more than one gift... frequency limit on gift parcels of food to Cuba. (C) Parties seeking authorization to exceed the...

  13. Smart tetroons for Lagrangian air-mass tracking during ACE 1

    NASA Astrophysics Data System (ADS)

    Businger, Steven; Johnson, Randy; Katzfey, Jack; Siems, Steven; Wang, Qing

    1999-05-01

    A series of "smart" tetroons was released from shipboard during the recent ACE 1 field experiment designed to monitor changes in the sulfur budget in a remote marine boundary layer (MBL) south of Tasmania, Australia. The smart tetroons were designed at NOAA Air Resources Laboratory Field Research Division to provide air parcel tracking information. The adjective smart here refers here to the fact that the buoyancy of the tetroons automatically adjusts through the action of a pump and valves when the tetroon travels vertically outside a range of pressures set prior to tetroon release. The smart tetroon design provides GPS location, barometric pressure, temperature, relative humidity, and tetroon status data via a transponder to the NCAR C-130 research aircraft flying in the vicinity of the tetroons. In this paper we will describe (1) the design and capability of the smart tetroons and their performance during the two Lagrangian experiments conducted during ACE 1, (2) the synoptic context of the Lagrangians, including the origin of the air parcels being tracked, and (3) the results of trajectory predictions derived from the National Center for Environmental Prediction (NCEP) Global Spectral Model (GSM) and Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) Division of Atmospheric Research (DAR) limited-area model.

  14. 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.

  15. MarsAtlas: A cortical parcellation atlas for functional mapping.

    PubMed

    Auzias, Guillaume; Coulon, Olivier; Brovelli, Andrea

    2016-04-01

    An open question in neuroimaging is how to develop anatomical brain atlases for the analysis of functional data. Here, we present a cortical parcellation model based on macroanatomical information and test its validity on visuomotor-related cortical functional networks. The parcellation model is based on a recently developed cortical parameterization method (Auzias et al., [2013]: IEEE Trans Med Imaging 32:873-887), called HIP-HOP. This method exploits a set of primary and secondary sulci to create an orthogonal coordinate system on the cortical surface. A natural parcellation scheme arises from the axes of the HIP-HOP model running along the fundus of selected sulci. The resulting parcellation scheme, called MarsAtlas, complies with dorsoventral/rostrocaudal direction fields and allows inter-subject matching. To test it for functional mapping, we analyzed a MEG dataset collected from human participants performing an arbitrary visuomotor mapping task. Single-trial high-gamma activity, HGA (60-120 Hz), was estimated using spectral analysis and beamforming techniques at cortical areas arising from a Talairach atlas (i.e., Brodmann areas) and MarsAtlas. Using both atlases, we confirmed that visuomotor associations involve an increase in HGA over the sensorimotor and fronto-parietal network, in addition to medial prefrontal areas. However, MarsAtlas provided: (1) crucial functional information along both the dorsolateral and rostrocaudal direction; (2) an increase in statistical significance. To conclude, our results suggest that the MarsAtlas is a valid anatomical atlas for functional mapping, and represents a potential anatomical framework for integration of functional data arising from multiple techniques such as MEG, intracranial EEG and fMRI. PMID:26813563

  16. Functional connectivity based parcellation of the human medial temporal lobe.

    PubMed

    Wang, Shao-Fang; Ritchey, Maureen; Libby, Laura A; Ranganath, Charan

    2016-10-01

    Regional differences in large-scale connectivity have been proposed to underlie functional specialization along the anterior-posterior axis of the medial temporal lobe (MTL), including the hippocampus (HC) and the parahippocampal gyrus (PHG). However, it is unknown whether functional connectivity (FC) can be used reliably to parcellate the human MTL. The current study aimed to differentiate subregions of the HC and the PHG based on patterns of whole-brain intrinsic FC. FC maps were calculated for each slice along the longitudinal axis of the PHG and the HC. A hierarchical clustering algorithm was then applied to these data in order to group slices according to the similarity of their connectivity patterns. Surprisingly, three discrete clusters were identified in the PHG. Two clusters corresponded to the parahippocampal cortex (PHC) and the perirhinal cortex (PRC), and these regions showed preferential connectivity with previously described posterior-medial and anterior-temporal networks, respectively. The third cluster corresponded to an anterior PRC region previously described as area 36d, and this region exhibited preferential connectivity with auditory cortical areas and with a network involved in visceral processing. The three PHG clusters showed different profiles of activation during a memory-encoding task, demonstrating that the FC-based parcellation identified functionally dissociable sub-regions of the PHG. In the hippocampus, no sub-regions were identified via the parcellation procedure. These results indicate that connectivity-based methods can be used to parcellate functional regions within the MTL, and they suggest that studies of memory and high-level cognition need to differentiate between PHC, posterior PRC, and anterior PRC.

  17. The Brain Atlas Concordance Problem: Quantitative Comparison of Anatomical Parcellations

    PubMed Central

    Bohland, Jason W.; Bokil, Hemant; Allen, Cara B.; Mitra, Partha P.

    2009-01-01

    Many neuroscientific reports reference discrete macro-anatomical regions of the brain which were delineated according to a brain atlas or parcellation protocol. Currently, however, no widely accepted standards exist for partitioning the cortex and subcortical structures, or for assigning labels to the resulting regions, and many procedures are being actively used. Previous attempts to reconcile neuroanatomical nomenclatures have been largely qualitative, focusing on the development of thesauri or simple semantic mappings between terms. Here we take a fundamentally different approach, discounting the names of regions and instead comparing their definitions as spatial entities in an effort to provide more precise quantitative mappings between anatomical entities as defined by different atlases. We develop an analytical framework for studying this brain atlas concordance problem, and apply these methods in a comparison of eight diverse labeling methods used by the neuroimaging community. These analyses result in conditional probabilities that enable mapping between regions across atlases, which also form the input to graph-based methods for extracting higher-order relationships between sets of regions and to procedures for assessing the global similarity between different parcellations of the same brain. At a global scale, the overall results demonstrate a considerable lack of concordance between available parcellation schemes, falling within chance levels for some atlas pairs. At a finer level, this study reveals spatial relationships between sets of defined regions that are not obviously apparent; these are of high potential interest to researchers faced with the challenge of comparing results that were based on these different anatomical models, particularly when coordinate-based data are not available. The complexity of the spatial overlap patterns revealed points to problems for attempts to reconcile anatomical parcellations and nomenclatures using strictly

  18. 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.

  19. 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.

  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. Approaching Expert Results Using a Hierarchical Cerebellum Parcellation Protocol for Multiple Inexpert Human Raters

    PubMed Central

    Bogovic, John A.; Jedynak, Bruno; Rigg, Rachel; Du, Annie; Landman, Bennett A.; Prince, Jerry L.; Ying, Sarah H.

    2012-01-01

    Volumetric measurements obtained from image parcellation have been instrumental in uncovering structure-function relationships. However, anatomical study of the cerebellum is a challenging task. Because of its complex structure, expert human raters have been necessary for reliable and accurate segmentation and parcellation. Such delineations are time-consuming and prohibitively expensive for large studies. Therefore, we present a three-part cerebellar parcellation system that utilizes multiple inexpert human raters that can efficiently and expediently produce results nearly on par with those of experts. This system includes a hierarchical delineation protocol, a rapid verification and evaluation process, and statistical fusion of the inexpert rater parcellations. The quality of the raters’ and fused parcellations was established by examining their Dice similarity coefficient, region of interest (ROI) volumes, and the intraclass correlation coefficient of region volume. The intra-rater ICC was found to be 0.93 at the finest level of parcellation. PMID:22975160

  2. Co-activation based parcellation of the human frontal pole.

    PubMed

    Ray, K L; Zald, D H; Bludau, S; Riedel, M C; Bzdok, D; Yanes, J; Falcone, K E; Amunts, K; Fox, P T; Eickhoff, S B; Laird, A R

    2015-12-01

    Historically, the human frontal pole (FP) has been considered as a single architectonic area. Brodmann's area 10 is located in the frontal lobe with known contributions in the execution of various higher order cognitive processes. However, recent cytoarchitectural studies of the FP in humans have shown that this portion of cortex contains two distinct cytoarchitectonic regions. Since architectonic differences are accompanied by differential connectivity and functions, the frontal pole qualifies as a candidate region for exploratory parcellation into functionally discrete sub-regions. We investigated whether this functional heterogeneity is reflected in distinct segregations within cytoarchitectonically defined FP-areas using meta-analytic co-activation based parcellation (CBP). The CBP method examined the co-activation patterns of all voxels within the FP as reported in functional neuroimaging studies archived in the BrainMap database. Voxels within the FP were subsequently clustered into sub-regions based on the similarity of their respective meta-analytically derived co-activation maps. Performing this CBP analysis on the FP via k-means clustering produced a distinct 3-cluster parcellation for each hemisphere corresponding to previously identified cytoarchitectural differences. Post-hoc functional characterization of clusters via BrainMap metadata revealed that lateral regions of the FP mapped to memory and emotion domains, while the dorso- and ventromedial clusters were associated broadly with emotion and social cognition processes. Furthermore, the dorsomedial regions contain an emphasis on theory of mind and affective related paradigms whereas ventromedial regions couple with reward tasks. Results from this study support previous segregations of the FP and provide meta-analytic contributions to the ongoing discussion of elucidating functional architecture within human FP. PMID:26254112

  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. 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.

  5. 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

  6. Analyzing Shuttle Orbiter Trajectories

    NASA Technical Reports Server (NTRS)

    Lear, W. M.

    1986-01-01

    LRBET4 program best-estimated-of-trajectory (BET) calculation for post-flight trajectory analysis of Shuttle orbiter. Produces estimated measurements for comparing predicted and actual trajectory of Earth-orbiting spacecraft. Kalman filter and smoothing filter applied to input data to estimate state vector, reduce noise, and produce BET. LRBET4 written in FORTRAN IV for batch execution.

  7. Cerebellar Functional Parcellation Using Sparse Dictionary Learning Clustering.

    PubMed

    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.

  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. 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...

  10. 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...

  11. 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...

  12. 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...

  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 5...

  14. 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...

  15. 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...

  16. 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...

  17. 77 FR 43561 - Proposed Eligibility Criteria for Bound Printed Matter Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-25

    ... 111 Proposed Eligibility Criteria for Bound Printed Matter Parcels AGENCY: Postal Service TM . ACTION... criterion for eligibility of Bound Printed Matter (BPM) parcels by adding a physical density threshold for... matter, weighing no more than 15 pounds and requiring postage payment by permit imprint. BPM is...

  18. 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.

  19. 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.

  20. Plutonium in the air in Kurchatov, Kazakhstan.

    PubMed

    Lehto, J; Salminen, S; Jaakkola, T; Outola, I; Pulli, S; Paatero, J; Tarvainen, M; Ristonmaa, S; Zilliacus, R; Ossintsev, A; Larin, V

    2006-07-31

    Weekly air samples of 25000 m(3) volume were taken with two air samplers over a period of one year in 2000-2001 in the town of Kurchatov in Kazakhstan. For another three-month period in 2001, the samplers were run in the city of Astana, about 500 km west of Kurchatov. (137)Cs, Pu and U concentrations were determined from the filters. Pu activities in Kurchatov varied in a 100-fold range; median (239,240)Pu activities were 100 nBq/m(3) and (238)Pu activities 34 nBq/m(3). The corresponding values for Astana were considerably lower: 29 and 9 nBq/m(3), respectively, and in half of the filters the (238)Pu activity was below the detection limit. Plutonium concentration correlated with the amount of dust retained on the filters only at the highest dust loads. Also no correlation between wind speed and the plutonium activity in the filters was observed. Thus, resuspension does not seem to be the mechanism responsible for the airborne plutonium. No clear seasonal variation of Pu air concentration was observed, though levels were somewhat elevated in February to April. There was no correlation between the plutonium and (137)Cs concentrations. In most of the filters the cesium concentration was below the detection limit, but in those filters where it could be detected the cesium concentration was practically constant at 3.9+/-1.6 microBq/m(3). Dose estimation for the inhalation of the airborne plutonium gave a low value of 0.018 microSv/a for the inhabitants in Kurchatov, which is about a thousand times lower than the dose caused by the naturally occurring (210)Po. Air parcel trajectory analysis indicated that the observed Pu activities in the air could not unambiguously be attributed to the most contaminated areas at the Semipalatinsk Test Site.

  1. The impact of mixing on Age of Air

    NASA Astrophysics Data System (ADS)

    Garny, Hella; Birner, Thomas; Bönisch, Harald

    2013-04-01

    Transport in the stratosphere is determined both by the mean meridional circulation and two-way mixing. Stratospheric age of air (AoA) is a measure of the integrated effect of all transport processes that affected an air parcel on its way through the stratosphere after crossing the tropopause. Mean AoA is often used to quantify the transport circulation in the stratosphere, namely the Brewer-Dobson Circulation (BDC). Global models project an increase in the mean meridional circulation in a changing climate, and simultaneously a decrease in AoA. However, evidence of changes in mean AoA from observations is weak. To infer from the AoA measurements on changes in the residual circulation, that cannot be measured directly, a better understanding of the relation between AoA and the residual circulation is necessary. Global models provide residual circulation data consistent with AoA, and thus can be used to investigate this relationship. We use trajectories driven only by the residual circulation to derive the hypothetical 'age' that air would have if it was transported only by the residual circulation. This quantity is referred to as 'residual circulation transit time' (RCTT). The difference between AoA and RCTT is then the additional aging of air caused by mixing processes. It is shown that this aging by mixing is positive throughout the lower stratosphere, only in the lowermost stratosphere at high latitudes, air is younger than expected from residual circulation transport only. The processes of the impact of mixing on AoA are further investigated using a simple tropical leaky pipe (TLP) model. The TLP model can explain the general increase of AoA in the lower stratosphere and above by mixing with the recirculation of air parcels. Aging by mixing is dependent both on 1) the mixing strength, that controls the fraction of air that recirculates, and 2) the residual circulation strength, that controls the speed of recirculation. Thus, stronger mixing increases aging by

  2. 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.

  3. 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

  4. Trajectories of martian habitability.

    PubMed

    Cockell, Charles S

    2014-02-01

    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.

  5. Trajectories of martian habitability.

    PubMed

    Cockell, Charles S

    2014-02-01

    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. PMID:24506485

  6. SMI-32 parcellates the visual cortical areas of the marmoset.

    PubMed

    Baldauf, Zsolt B

    The distribution pattern of SMI-32-immunoreactivity (SMI-32-ir) of neuronal elements was examined in the visual cortical areas of marmoset monkey. Layer IV of the primary visual cortex (V1) and layers III and V of the extrastriate areas showed the most abundant SMI-32-ir. The different areal and laminar distribution of SMI-32-ir allowed the distinction between various extrastriate areas and determined their exact anatomical boundaries in the New World monkey, Callithrix penicillata. It is shown here that the parcellating nature of SMI-32 described earlier in the visual cortical areas of other mammals - including Old World monkeys - is also present in the marmoset. Furthermore, a comparison became possible between the chemoanatomical organization of New World and Old World primates' visual cortical areas.

  7. 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.

  8. Characterization of sources for southern African aerosols through fatty acid and trajectory analyses

    NASA Astrophysics Data System (ADS)

    Billmark, Kaycie A.; Swap, Robert J.; Macko, Stephen A.

    2003-07-01

    Biogeochemical cycles in southern Africa are affected by emissions from extensive biomass burning. Emitted trace gases and aerosols frequently accumulate and recirculate in the well-defined synoptic pattern that persists for long time periods over southern Africa. The role of organic aerosols during atmospheric transport and the influence of neighboring air masses on biogeochemical dynamics in this nutrient-limited region are insufficiently studied. The Southern African Regional Science Initiative (SAFARI 2000) was conducted in part to investigate the impacts of this large-scale transport and deposition of increasingly anthropogenic emissions on southern African biogeochemical cycling. This study explores the understanding of regional atmospheric transport through the identification of chemical biomarkers to describe aerosols collected during the SAFARI 2000 dry season research campaign. Total suspended particulate aerosol samples were collected diurnally for a period of two weeks in Mongu, Zambia. Mongu is bordered by the Zambezi River on the west and the Miombo woodland savanna in all other directions. It also lies on the northern extent of the Kalahari Desert. This region is characterized by high biomass burning emissions of river floodplain grasses and woodland savanna during the dry season. Fatty acids were extracted from the collected aerosols and analyzed using gas chromatography. The resultant fatty acid compositions were examined for temporal patterns and trends. Furthermore, these results were compared to both synoptic meteorological patterns over the region, as well as to modeled air parcel trajectories, to gain insight into changes in aerosol composition resulting from changes in atmospheric transports from regions of different vegetation. The results of these analyses confirm that abundances of fatty acids are dependent on local and synoptic meteorology and can thus be used as an additional geochemical tracer to better describe aerosol sources and

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. Trajectory of the mt. St. Augustine 1976 eruption ash cloud.

    PubMed

    Meinel, A B; Meinel, M P; Shaw, G E

    1976-07-30

    The ash clouds from the 23 January 1976 eruption of Mt. St. Augustine in Alaska drifted over Arizona on 25 January at an altitude of 6 kilometers as deduced from air trajectories and the observation of an unusual cloud.

  14. 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.

  15. Nonlinear trajectory navigation

    NASA Astrophysics Data System (ADS)

    Park, Sang H.

    Trajectory navigation entails the solution of many different problems that arise due to uncertain knowledge of the spacecraft state, including orbit prediction, correction maneuver design, and trajectory estimation. In practice, these problems are usually solved based on an assumption that linear dynamical models sufficiently approximate the local trajectory dynamics and their associated statistics. However, astrodynamics problems are nonlinear in general and linear spacecraft dynamics models can fail to characterize the true trajectory dynamics when the system is subject to a highly unstable environment or when mapped over a long time period. This limits the performance of traditional navigation techniques and can make it difficult to perform precision analysis or robust navigation. This dissertation presents an alternate method for spacecraft trajectory navigation based on a nonlinear local trajectory model and their statistics in an analytic framework. For a given reference trajectory, we first solve for the higher order Taylor series terms that describe the localized nonlinear motion and develop an analytic expression for the relative solution flow. We then discuss the nonlinear dynamical mapping of a spacecraft's probability density function by solving the Fokker-Planck equation for a deterministic system. From this result we derive an analytic method for orbit uncertainty propagation which can replicate Monte-Carlo simulations with the benefit of added flexibility in initial orbit statistics. Using this approach, we introduce the concept of the statistically correct trajectory where we directly incorporate statistical information about an orbit state into the trajectory design process. As an extension of this concept, we define a nonlinear statistical targeting method where we solve for a correction maneuver which intercepts the desired target on average. Then we apply our results to a Bayesian filtering problem to obtain a general filtering algorithm for

  16. Why item parcels are (almost) never appropriate: two wrongs do not make a right--camouflaging misspecification with item parcels in CFA models.

    PubMed

    Marsh, Herbert W; Lüdtke, Oliver; Nagengast, Benjamin; Morin, Alexandre J S; Von Davier, Matthias

    2013-09-01

    The present investigation has a dual focus: to evaluate problematic practice in the use of item parcels and to suggest exploratory structural equation models (ESEMs) as a viable alternative to the traditional independent clusters confirmatory factor analysis (ICM-CFA) model (with no cross-loadings, subsidiary factors, or correlated uniquenesses). Typically, it is ill-advised to (a) use item parcels when ICM-CFA models do not fit the data, and (b) retain ICM-CFA models when items cross-load on multiple factors. However, the combined use of (a) and (b) is widespread and often provides such misleadingly good fit indexes that applied researchers might believe that misspecification problems are resolved--that 2 wrongs really do make a right. Taking a pragmatist perspective, in 4 studies we demonstrate with responses to the Rosenberg Self-Esteem Inventory (Rosenberg, 1965), Big Five personality factors, and simulated data that even small cross-loadings seriously distort relations among ICM-CFA constructs or even decisions on the number of factors; although obvious in item-level analyses, this is camouflaged by the use of parcels. ESEMs provide a viable alternative to ICM-CFAs and a test for the appropriateness of parcels. The use of parcels with an ICM-CFA model is most justifiable when the fit of both ICM-CFA and ESEM models is acceptable and equally good, and when substantively important interpretations are similar. However, if the ESEM model fits the data better than the ICM-CFA model, then the use of parcels with an ICM-CFA model typically is ill-advised--particularly in studies that are also interested in scale development, latent means, and measurement invariance.

  17. 76 FR 23749 - Intelligent Mail Package Barcode (IMpb) Implementation for Commercial Parcels

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-28

    ... 111 Intelligent Mail Package Barcode (IMpb) Implementation for Commercial Parcels AGENCY: Postal... currently enhancing its operational capability to allow for the scanning of Intelligent Mail package barcodes (IMpb) and other extra services barcodes via automated processing equipment and Intelligent...

  18. 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

  19. Connectivity-based parcellation of the human frontal polar cortex.

    PubMed

    Moayedi, Massieh; Salomons, Tim V; Dunlop, Katharine A M; Downar, Jonathan; Davis, Karen D

    2015-09-01

    The frontal pole corresponds to Brodmann area (BA) 10, the largest single architectonic area in the human frontal lobe. Generally, BA10 is thought to contain two or three subregions that subserve broad functions such as multitasking, social cognition, attention, and episodic memory. However, there is a substantial debate about the functional and structural heterogeneity of this large frontal region. Previous connectivity-based parcellation studies have identified two or three subregions in the human frontal pole. Here, we used diffusion tensor imaging to assess structural connectivity of BA10 in 35 healthy subjects and delineated subregions based on this connectivity. This allowed us to determine the correspondence of structurally based subregions with the scheme previously defined functionally. Three subregions could be defined in each subject. However, these three subregions were not spatially consistent between subjects. Therefore, we accepted a solution with two subregions that encompassed the lateral and medial frontal pole. We then examined resting-state functional connectivity of the two subregions and found significant differences between their connectivities. The medial cluster was connected to nodes of the default-mode network, which is implicated in internally focused, self-related thought, and social cognition. The lateral cluster was connected to nodes of the executive control network, associated with directed attention and working memory. These findings support the concept that there are two major anatomical subregions of the frontal pole related to differences in functional connectivity.

  20. Intracellular parcel service: current issues in intracellular membrane trafficking.

    PubMed

    Herrmann, Johannes M; Spang, Anne

    2015-01-01

    Eukaryotic cells contain a multitude of membrane structures that are connected through a highly dynamic and complex exchange of their constituents. The vibrant instability of these structures challenges the classical view of defined, static compartments that are connected by different types of vesicles. Despite this astonishing complexity, proteins and lipids are accurately transported into the different intracellular membrane systems. Over the past few decades many factors have been identified that either mediate or regulate intracellular membrane trafficking. Like in a modern parcel sorting system of a logistics center, the cargo typically passes through several sequential sorting stations until it finally reaches the location that is specified by its individual address label. While each membrane system employs specific sets of factors, the transport processes typically operate on common principles. With the advent of genome- and proteome-wide screens, the availability of mutant collections, exciting new developments in microscope technology and sophisticated methods to study their dynamics, the future promises a broad and comprehensive picture of the processes by which eukaryotic cells sort their proteins.

  1. 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

  2. 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.

  3. Hydrocarbon Observations and Ozone Production Rates in Western Houston During the Texas 2000 Air Quality Study

    SciTech Connect

    Berkowitz, Carl M.; Spicer, Chet W.; Doskey, Paul V.

    2005-06-01

    Measurements of total non-methane hydrocarbon in whole air canisters collected from the top of a skyscraper on the western edge of Houston, Texas are summarized with an emphasis on samples collected during the passage of plumes of O{sub 3} and the associated rapid increase in the mixing ratio of this species. The back-trajectories associated with these events showed a pronounced deceleration of air parcels over central and western Houston and were not necessarily associated with direct passage over the petrochemical plants located in the heavily industrialized eastern part of Houston. As a result of the time these air parcels spent over the central and western parts of Houston, their VOC mix and associated chemical production rates were expected to differ from similar observations made over eastern Houston from aircraft sampling at low altitudes. Although periods of high O{sub 3} in the western part of the city were closely associated with light alkenes, these same observations show isoprene to make a significant contribution to the total VOC reactivity in the early afternoon (the start of peak photochemical activity) in contrast to observations made east of our sampling site that found the reactivity to be dominated by anthropogenic species. By initializing a 0-dimensional chemical kinetic model with observations made at the Williams Tower, we find that the ozone production efficiency scaled linearly to the ratio of total hydrocarbons and NO{sub x}, with an average OPE of 7.2, ranging from 2.3 to 16.9; these values are smaller than those reported in eastern Houston, suggesting a strong gradient in photochemical productivity across the city.

  4. Improving reliability of subject-level resting-state fMRI parcellation with shrinkage estimators.

    PubMed

    Mejia, Amanda F; Nebel, Mary Beth; Shou, Haochang; Crainiceanu, Ciprian M; Pekar, James J; Mostofsky, Stewart; Caffo, Brian; Lindquist, Martin A

    2015-05-15

    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often a necessary step for defining the network nodes used in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the inherent low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage-based estimators of such measures, allowing the noisy subject-specific estimator to "borrow strength" in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw inter-voxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. While we employ a standard spectral clustering approach, our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets - a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute resting-state fMRI scans from 20 subjects - we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw correlation estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor cortex by

  5. Improving Reliability of Subject-Level Resting-State fMRI Parcellation with Shrinkage Estimators

    PubMed Central

    Mejia, Amanda F.; Nebel, Mary Beth; Shou, Haochang; Crainiceanu, Ciprian M.; Pekar, James J.; Mostofsky, Stewart; Caffo, Brian; Lindquist, Martin A.

    2015-01-01

    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often a necessary step for defining the network nodes used in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the inherent low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage-based estimators of such measures, allowing the noisy subject-specific estimator to “borrow strength” in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw inter-voxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. While we employ a standard spectral clustering approach, our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets – a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute resting-state fMRI scans from 20 subjects – we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw correlation estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor

  6. Improving reliability of subject-level resting-state fMRI parcellation with shrinkage estimators.

    PubMed

    Mejia, Amanda F; Nebel, Mary Beth; Shou, Haochang; Crainiceanu, Ciprian M; Pekar, James J; Mostofsky, Stewart; Caffo, Brian; Lindquist, Martin A

    2015-05-15

    A recent interest in resting state functional magnetic resonance imaging (rsfMRI) lies in subdividing the human brain into anatomically and functionally distinct regions of interest. For example, brain parcellation is often a necessary step for defining the network nodes used in connectivity studies. While inference has traditionally been performed on group-level data, there is a growing interest in parcellating single subject data. However, this is difficult due to the inherent low signal-to-noise ratio of rsfMRI data, combined with typically short scan lengths. A large number of brain parcellation approaches employ clustering, which begins with a measure of similarity or distance between voxels. The goal of this work is to improve the reproducibility of single-subject parcellation using shrinkage-based estimators of such measures, allowing the noisy subject-specific estimator to "borrow strength" in a principled manner from a larger population of subjects. We present several empirical Bayes shrinkage estimators and outline methods for shrinkage when multiple scans are not available for each subject. We perform shrinkage on raw inter-voxel correlation estimates and use both raw and shrinkage estimates to produce parcellations by performing clustering on the voxels. While we employ a standard spectral clustering approach, our proposed method is agnostic to the choice of clustering method and can be used as a pre-processing step for any clustering algorithm. Using two datasets - a simulated dataset where the true parcellation is known and is subject-specific and a test-retest dataset consisting of two 7-minute resting-state fMRI scans from 20 subjects - we show that parcellations produced from shrinkage correlation estimates have higher reliability and validity than those produced from raw correlation estimates. Application to test-retest data shows that using shrinkage estimators increases the reproducibility of subject-specific parcellations of the motor cortex by

  7. 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...

  8. Ornithopter transition trajectories

    NASA Astrophysics Data System (ADS)

    Dietl, John M.; Garcia, Ephrahim

    2010-04-01

    The design of stable trim conditions for forward flight and for hover has been achieved. In forward flight, an ornithopter is configured like a conventional airplane or large bird. Its fuselage is essentially horizontal and the wings heave in a vertical plane. In hover, however, the body pitches vertically so that the wing stroke in the horizontal plane. Thrust directed downward, the vehicle remains aloft while the downdraft envelops the tail to provide enough flow for vehicle control and stabilization. To connect these trajectories dynamically is the goal. The naïve approach-to choose two stable trajectories and switch between them-has been accomplished. A new approach is to establish an open-loop trajectory through a trajectory optimization algorithm-optimized for shortest altitude drop, shortest stopping distance, or lowest energy consumption.

  9. Optimal space trajectories

    NASA Astrophysics Data System (ADS)

    Marec, J. P.

    Techniques for the optimization (in terms of minimal mass loss) of spacecraft trajectories are developed. The optimal transfer is defined; a model of the propulsion system is presented; the two-impulse Hohmann transfer between coplanar circular orbits is shown to be the optimal trajectory for that case; and the problems of optimal transfer in general, uniform, and central gravitational fields are analyzed. A number of specific cases are examined and illustrated with diagrams and graphs.

  10. 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.

  11. 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.

  12. Model-Based Analysis of Electric Drive Options for Medium-Duty Parcel Delivery Vehicles: Preprint

    SciTech Connect

    Barnitt, R. A.; Brooker, A. D.; Ramroth, L.

    2010-12-01

    Medium-duty vehicles are used in a broad array of fleet applications, including parcel delivery. These vehicles are excellent candidates for electric drive applications due to their transient-intensive duty cycles, operation in densely populated areas, and relatively high fuel consumption and emissions. The National Renewable Energy Laboratory (NREL) conducted a robust assessment of parcel delivery routes and completed a model-based techno-economic analysis of hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle configurations. First, NREL characterized parcel delivery vehicle usage patterns, most notably daily distance driven and drive cycle intensity. Second, drive-cycle analysis results framed the selection of drive cycles used to test a parcel delivery HEV on a chassis dynamometer. Next, measured fuel consumption results were used to validate simulated fuel consumption values derived from a dynamic model of the parcel delivery vehicle. Finally, NREL swept a matrix of 120 component size, usage, and cost combinations to assess impacts on fuel consumption and vehicle cost. The results illustrated the dependency of component sizing on drive-cycle intensity and daily distance driven and may allow parcel delivery fleets to match the most appropriate electric drive vehicle to their fleet usage profile.

  13. 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.

  14. 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.

  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. Trajectory Analysis and Optimization System

    1996-06-04

    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,more » and trajectories involving more than one vehicle can be computed within a single problem.« less

  17. Accounting for Parcel-Allocation Variability in Practice: Combining Sources of Uncertainty and Choosing the Number of Allocations.

    PubMed

    Sterba, Sonya K; Rights, Jason D

    2016-01-01

    Item parceling remains widely used under conditions that can lead to parcel-allocation variability in results. Hence, researchers may be interested in quantifying and accounting for parcel-allocation variability within sample. To do so in practice, three key issues need to be addressed. First, how can we combine sources of uncertainty arising from sampling variability and parcel-allocation variability when drawing inferences about parameters in structural equation models? Second, on what basis can we choose the number of repeated item-to-parcel allocations within sample? Third, how can we diagnose and report proportions of total variability per estimate arising due to parcel-allocation variability versus sampling variability? This article addresses these three methodological issues. Developments are illustrated using simulated and empirical examples, and software for implementing them is provided.

  18. Hydrologic evaluation and water-supply considerations for five Paiute Indian land parcels, Millard, Sevier, and Iron counties, southwestern Utah

    USGS Publications Warehouse

    Price, Don; Stephens, D.W.; Conroy, L.S.

    1989-01-01

    The hydrologic resources in and adjacent to five parcels of land held in trust for the Paiute Indian Tribe of Utah were evaluated. The land, located in southwestern Utah, is generally arid and has had only limited use for grazing. The parcels are located near the towns of Cove Fort, Joseph, Koosharem, and Kanarraville. On the basis of available geohydrologic and hydrologic data, water of suitable quality is locally available in the areas of all parcels for domestic, stock, recreation, and limited irrigation use. Developing this water for use on the parcels would potentially involve obtaining water rights, drilling wells, and constructing diversion structures. Surface water apparently is the most favorable source of supply available for the Joseph parcel, and groundwater apparently is the most favorable source of supply available for the other parcels. (USGS)

  19. 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%. PMID:25689830

  20. 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

  1. 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.

  2. Computational methods for reentry trajectories

    NASA Astrophysics Data System (ADS)

    Anselmo, L.; Pardini, C.

    The trajectory modeling of uncontrolled satellites close to reentry in the atmosphere is still a challenging activity. Tracking data may be sparse and not particularly accurate, the objects complicate shape and unknown attitude evolution may render quite tricky the aerodynamic computations and, last but not the least, the models used to predict the air density at the altitudes of interest, as a function of solar and geomagnetic activity, are affected by significant uncertainties. This paper presents the techniques developed and the experience matured in the field at ISTI (formerly CNUCE), specifically in support of the reentry predictions of risky space objects carried out for the Italian civil protection authorities. In these cases, an appropriate management of the intrinsic uncertainties of the problem is critical for the dissemination of the results, avoiding, as much as possible, misunderstandings and unjustified alarm.

  3. Calculation of Electron Trajectories

    1982-06-01

    EGUN, the SLAC Electron Trajectory Program, computes trajectories of charged particles in electrostatic and magnetostatic focusing systems including the effects of space charge and self-magnetic fields. Starting options include Child''s Law conditions on cathodes of various shapes, user-specified initial conditions for each ray, and a combination of Child''s Law conditions and user specifications. Either rectangular or cylindrically symmetric geometry may be used. Magnetic fields may be specified using arbitrary configuration of coils, or the outputmore » of a magnet program, such as Poisson, or by an externally calculated array of the axial fields.« less

  4. 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

  5. Identifying functional subdivisions in the human brain using meta-analytic activation modeling-based parcellation.

    PubMed

    Yang, Yong; Fan, Lingzhong; Chu, Congying; Zhuo, Junjie; Wang, Jiaojian; Fox, Peter T; Eickhoff, Simon B; Jiang, Tianzi

    2016-01-01

    Parcellation of the human brain into fine-grained units by grouping voxels into distinct clusters has been an effective approach for delineating specific brain regions and their subregions. Published neuroimaging studies employing coordinate-based meta-analyses have shown that the activation foci and their corresponding behavioral categories may contain useful information about the anatomical-functional organization of brain regions. Inspired by these developments, we proposed a new parcellation scheme called meta-analytic activation modeling-based parcellation (MAMP) that uses meta-analytically obtained information. The raw meta data, including the experiments and the reported activation coordinates related to a brain region of interest, were acquired from the Brainmap database. Using this data, we first obtained the "modeled activation" pattern by modeling the voxel-wise activation probability given spatial uncertainty for each experiment that featured at least one focus within the region of interest. Then, we processed these "modeled activation" patterns across the experiments with a K-means clustering algorithm to group the voxels into different subregions. In order to verify the reliability of the method, we employed our method to parcellate the amygdala and the left Brodmann area 44 (BA44). The parcellation results were quite consistent with previous cytoarchitectonic and in vivo neuroimaging findings. Therefore, the MAMP proposed in the current study could be a useful complement to other methods for uncovering the functional organization of the human brain.

  6. 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.

  7. 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.

  8. 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.

  9. Parcel: Project for the Automatic Restructuring and Concurrent Evaluation of Lisp

    SciTech Connect

    Harrison, W.L. III; Padua, D.A.

    1987-01-01

    Parcel (Project for the Automatic Restructuring and Concurrent Evaluation of Lisp) is an investigation of the problem of compiling Lisp for evaluation on a shared memory multiprocessor. In this paper, we present an overview of the process of compilation in Parcel. This process consists, broadly, of an interprocedural analysis, followed by the function-level restructuring of the lambda expressions composing a program. We discuss both of the phases, and illustrate the steps of restructuring with a few examples. A novel representation for s-expressions is employed in Parcel, to facilitate the parallel creation and access of lists; we review this representation, and discuss its implications for the compilation process. 14 refs., 8 figs.

  10. [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.

  11. Parcellation of the human orbitofrontal cortex based on gray matter volume covariance.

    PubMed

    Liu, Huaigui; Qin, Wen; Qi, Haotian; Jiang, Tianzi; Yu, Chunshui

    2015-02-01

    The human orbitofrontal cortex (OFC) is an enigmatic brain region that cannot be parcellated reliably using diffusional and functional magnetic resonance imaging (fMRI) because there is signal dropout that results from an inherent defect in imaging techniques. We hypothesise that the OFC can be reliably parcellated into subregions based on gray matter volume (GMV) covariance patterns that are derived from artefact-free structural images. A total of 321 healthy young subjects were examined by high-resolution structural MRI. The OFC was parcellated into subregions-based GMV covariance patterns; and then sex and laterality differences in GMV covariance pattern of each OFC subregion were compared. The human OFC was parcellated into the anterior (OFCa), medial (OFCm), posterior (OFCp), intermediate (OFCi), and lateral (OFCl) subregions. This parcellation scheme was validated by the same analyses of the left OFC and the bilateral OFCs in male and female subjects. Both visual observation and quantitative comparisons indicated a unique GMV covariance pattern for each OFC subregion. These OFC subregions mainly covaried with the prefrontal and temporal cortices, cingulate cortex and amygdala. In addition, GMV correlations of most OFC subregions were similar across sex and laterality except for significant laterality difference in the OFCl. The right OFCl had stronger GMV correlation with the right inferior frontal cortex. Using high-resolution structural images, we established a reliable parcellation scheme for the human OFC, which may provide an in vivo guide for subregion-level studies of this region and improve our understanding of the human OFC at subregional levels.

  12. 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.

  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 shaping rendezvous guidance

    NASA Astrophysics Data System (ADS)

    Klumpp, A. R.

    The Space Station will bring a great increase in rendezvous traffic. Formerly, rendezvous has been expensive in terms of time and crew involvement. Multiple trajectory adjustments on separate orbits have been required to meet safety, lighting, and geometry requirements. This paper describes a new guidance technique in which the approach trajectory is shaped by a sequence of velocity increments in order to satisfy multiple constraints within a single orbit. The approach phase is planned before the mission, leaving a group of free parameters that are optimized by onboard guidance. Fuel penalties are typically a few percent, compared to unshaped Hohmann transfers, and total fuel costs can be less than those of more time-consuming ways of meeting the same requirements.

  15. 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

  16. 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...

  17. 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.

  18. 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.

  19. 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

  20. Optimal trajectory for the basketball free throw.

    PubMed

    Hamilton, G R; Reinschmidt, C

    1997-10-01

    Using a theoretical approach, we studied the basketball free throw as a function of angle, speed and spin at release. The ball was constrained to the sagittal plane bisecting the hoop and normal to the backboard, and was permitted to bounce and change spin on both backboard and hoop. Combinations of angle, speed and spin resulting in a successful shot were calculated analytically. Standard deviations for a shooter's angle and speed were used to predict the optimal trajectory for a specific position of release. An optimal trajectory was predicted which had an initial angle and speed of approximately 60 degrees and 7.3 m s(-1) respectively over the domain of spins (-2 to +2 m s(-1) surface speed; -16 to +16 rad s[1]). The effect of air resistance and the sagittal plane constraint on the predicted optimal trajectory were discussed and quantified. The optimal trajectory depended on both the anthropometric characteristics and accuracy of the shooter, but generally a high backspin with an angle and speed combination which sent the ball closer to the far rim of the basket than the near rim was advantageous. We provide recommendations for shooters as a function of the height of ball release.

  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. 9 CFR 325.2 - Parcel post and ferries deemed carriers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Parcel post and ferries deemed carriers. 325.2 Section 325.2 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF... to transportation by ferry of any products loaded on a truck or other vehicle, or otherwise moved...

  3. 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...

  4. Archaeological Survey of 56 Preselected Parcels on the AridLands Ecology Reserve

    SciTech Connect

    J. J. Sharpe.

    1999-04-22

    An archaeological survey of 56 preselected parcels on the Fitzner-Eberhardt Arid Lands Ecology (ALE) Reserve was undertaken in support of compensatory mitigation for the construction of the Environmental Restoration Disposal Facility (ERDF) cells 3 and 4 on the Hanford Site. This report presents the findings of the archaeological survey.

  5. 76 FR 14284 - Domestic Shipping Services Product Launch of Parcel Select Regional Ground

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-16

    .... Enter a minimum of 200 pieces or 50 pounds of mail for each mailing. Use the Electronic Verification... (electronic option only), insurance, and Hold For Pickup service. Markings and Mail Preparation The basic...); Standard Mail prepared as Not Flat-Machinable pieces or as machinable or irregular parcels...

  6. 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.

  7. Irreversibility with quantum trajectories.

    PubMed

    Wisniacki, D A; Borondo, F; Benito, R M

    2005-10-01

    Irreversibility is an important issue for many quantum processes. Loschmidt echoes, originally introduced as a way to gauge sensitivity to perturbations in quantum mechanics, have turned out to be a useful tool for its investigation. Following the philosophy supporting this idea, and using quantum trajectories as defined in the causal interpretation of quantum mechanics due to Bohm, we introduce in this paper a more informative alternative measure for irreversibility. The method is applied to the Bunimovich stadium billiard, a paradigmatic example of chaotic system, that constitutes an excellent model for mesoscopic devices.

  8. Dynamical collapse of trajectories

    NASA Astrophysics Data System (ADS)

    Biemond, J. J. Benjamin; de Moura, Alessandro P. S.; Grebogi, Celso; van de Wouw, Nathan; Nijmeijer, Henk

    2012-04-01

    Friction induces unexpected dynamical behaviour. In the paradigmatic pendulum and double-well systems with friction, modelled with differential inclusions, distinct trajectories can collapse onto a single point. Transversal homoclinic orbits display collapse and generate chaotic saddles with forward dynamics that is qualitatively different from the backward dynamics. The space of initial conditions converging to the chaotic saddle is fractal, but the set of points diverging from it is not: friction destroys the complexity of the forward dynamics by generating a unique horseshoe-like topology.

  9. 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. PMID:27471982

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Influence of the Saharan Air Layer on Atlantic tropical cyclone formation during the period 1-12 September 2003

    NASA Astrophysics Data System (ADS)

    Pan, Weiyu; Wu, Liguang; Shie, Chung-Lin

    2011-01-01

    Atmospheric Infrared Sounder (AIRS) data show that the Saharan air layer (SAL) is a dry, warm, and well-mixed layer between 950 and 500 hPa over the tropical Atlantic, extending westward from the African coast to the Caribbean Sea. The formations of both Hurricane Isabel and Tropical Depression 14 (TD14) were accompanied with outbreaks of SAL air during the period 1-12 September 2003, although TD14 failed to develop into a named tropical cyclone. The influence of the SAL on their formations is investigated by examining data from satellite observations and numerical simulations, in which AIRS data are incorporated into the MM5 model through the nudging technique. Analyses of the AIRS and simulation data suggest that the SAL may have played two roles in the formation of tropical cyclones during the period 1-12 September 2003. First, the outbreaks of SAL air on 3 and 8 September enhanced the transverse-vertical circulation with the rising motion along the southern edge of the SAL and the sinking motion inside the SAL, triggering the development of two tropical disturbances associated with Hurricane Isabel and TD14. Second, in addition to the reduced environmental humidity and enhanced static stability in the lower troposphere, the SAL dry air intruded into the inner region of these tropical disturbances as their cyclonic flows became strong. This effect may have slowed down the formation of Isabel and inhibited TD14 becoming a named tropical cyclone, while the enhanced vertical shear contributed little to tropical cyclone formation during this period. The 48-h trajectory calculations confirm that the parcels from the SAL can be transported into the inner region of an incipient tropical cyclone.

  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. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Multi-Contrast Multi-Atlas Parcellation of Diffusion Tensor Imaging of the Human Brain

    PubMed Central

    Tang, Xiaoying; Yoshida, Shoko; Hsu, John; Huisman, Thierry A. G. M.; Faria, Andreia V.; Oishi, Kenichi; Kutten, Kwame; Poretti, Andrea; Li, Yue; Miller, Michael I.; Mori, Susumu

    2014-01-01

    In this paper, we propose a novel method for parcellating the human brain into 193 anatomical structures based on diffusion tensor images (DTIs). This was accomplished in the setting of multi-contrast diffeomorphic likelihood fusion using multiple DTI atlases. DTI images are modeled as high dimensional fields, with each voxel exhibiting a vector valued feature comprising of mean diffusivity (MD), fractional anisotropy (FA), and fiber angle. For each structure, the probability distribution of each element in the feature vector is modeled as a mixture of Gaussians, the parameters of which are estimated from the labeled atlases. The structure-specific feature vector is then used to parcellate the test image. For each atlas, a likelihood is iteratively computed based on the structure-specific vector feature. The likelihoods from multiple atlases are then fused. The updating and fusing of the likelihoods is achieved based on the expectation-maximization (EM) algorithm for maximum a posteriori (MAP) estimation problems. We first demonstrate the performance of the algorithm by examining the parcellation accuracy of 18 structures from 25 subjects with a varying degree of structural abnormality. Dice values ranging 0.8–0.9 were obtained. In addition, strong correlation was found between the volume size of the automated and the manual parcellation. Then, we present scan-rescan reproducibility based on another dataset of 16 DTI images – an average of 3.73%, 1.91%, and 1.79% for volume, mean FA, and mean MD respectively. Finally, the range of anatomical variability in the normal population was quantified for each structure. PMID:24809486

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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.

  6. 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.

  7. 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.

  8. Four-body trajectory optimization

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

    A comprehensive optimization program has been developed for computing fuel-optimal trajectories between the earth and a point in the sun-earth-moon system. It presents methods for generating fuel optimal two-impulse trajectories which may originate at the earth or a point in space and fuel optimal three-impulse trajectories between two points in space. The extrapolation of the state vector and the computation of the state transition matrix are accomplished by the Stumpff-Weiss method. The cost and constraint gradients are computed analytically in terms of the terminal state and the state transition matrix. The 4-body Lambert problem is solved by using the Newton-Raphson method. An accelerated gradient projection method is used to optimize a 2-impulse trajectory with terminal constraint. The Davidon's Variance Method is used both in the accelerated gradient projection method and the outer loop of a 3-impulse trajectory optimization problem.

  9. Computational neuroanatomy using brain deformations: From brain parcellation to multivariate pattern analysis and machine learning.

    PubMed

    Davatzikos, Christos

    2016-10-01

    The past 20 years have seen a mushrooming growth of the field of computational neuroanatomy. Much of this work has been enabled by the development and refinement of powerful, high-dimensional image warping methods, which have enabled detailed brain parcellation, voxel-based morphometric analyses, and multivariate pattern analyses using machine learning approaches. The evolution of these 3 types of analyses over the years has overcome many challenges. We present the evolution of our work in these 3 directions, which largely follows the evolution of this field. We discuss the progression from single-atlas, single-registration brain parcellation work to current ensemble-based parcellation; from relatively basic mass-univariate t-tests to optimized regional pattern analyses combining deformations and residuals; and from basic application of support vector machines to generative-discriminative formulations of multivariate pattern analyses, and to methods dealing with heterogeneity of neuroanatomical patterns. We conclude with discussion of some of the future directions and challenges. PMID:27514582

  10. Computational neuroanatomy using brain deformations: From brain parcellation to multivariate pattern analysis and machine learning.

    PubMed

    Davatzikos, Christos

    2016-10-01

    The past 20 years have seen a mushrooming growth of the field of computational neuroanatomy. Much of this work has been enabled by the development and refinement of powerful, high-dimensional image warping methods, which have enabled detailed brain parcellation, voxel-based morphometric analyses, and multivariate pattern analyses using machine learning approaches. The evolution of these 3 types of analyses over the years has overcome many challenges. We present the evolution of our work in these 3 directions, which largely follows the evolution of this field. We discuss the progression from single-atlas, single-registration brain parcellation work to current ensemble-based parcellation; from relatively basic mass-univariate t-tests to optimized regional pattern analyses combining deformations and residuals; and from basic application of support vector machines to generative-discriminative formulations of multivariate pattern analyses, and to methods dealing with heterogeneity of neuroanatomical patterns. We conclude with discussion of some of the future directions and challenges.

  11. 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.

  12. 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

  13. Fractional trajectories: Decorrelation versus friction

    NASA Astrophysics Data System (ADS)

    Svenkeson, A.; Beig, M. T.; Turalska, M.; West, B. J.; Grigolini, P.

    2013-11-01

    The fundamental connection between fractional calculus and subordination processes is explored and affords a physical interpretation of a fractional trajectory, that being an average over an ensemble of stochastic trajectories. Heretofore what has been interpreted as intrinsic friction, a form of non-Markovian dissipation that automatically arises from adopting the fractional calculus, is shown to be a manifestation of decorrelations between trajectories. We apply the general theory developed herein to the Lotka-Volterra ecological model, providing new insight into the final equilibrium state. The relaxation time to achieve this state is also considered.

  14. 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.)

  15. Fast three-dimensional k-space trajectory design using missile guidance ideas.

    PubMed

    Mir, Roberto; Guesalaga, Andres; Spiniak, Juan; Guarini, Marcelo; Irarrazaval, Pablo

    2004-08-01

    Three-dimensional (3D) k-space trajectories are needed to acquire volumetric images in MRI. While scan time is determined by the trajectory efficiency, image quality and distortions depend on the shape of the trajectories. There are several 3D trajectory strategies for sampling the k-space using rectilinear or curve schemes. Since there is no evidence about their optimality in terms of image quality and acquisition time, a new design method based on missile guidance ideas is explored. Since air-to-air missile guidance shares similar goals and constraints with the problem of k-space trajectory design, a control approach for missiles is used to design a 3D trajectory. The k-space is divided into small cubes, and each one is treated as a target to be sampled. The main goal is to cover the entire space as quickly and efficiently as possible, with good performance under different conditions. This novel design method is compared to other trajectories using simulated and real data. As an example, a trajectory that requires 0.11 times the number of shots needed by the cylindrical 3DFT acquisition was designed. This trajectory requires more shots (1.66 times) than the stack of spirals, but behaves better under nonideal conditions, such as off-resonance and motion.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 40 CFR 52.2581 - Significant deterioration of air quality.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... provisions for prevention of significant deterioration of air quality at 40 CFR 52.21 are applicable to the... 164 of the Clean Air Act and the provisions of 40 CFR 52.21(g), those parcels of the Forest County... T35N R15E. (xxx) E1/2 of Section 28 of T35N R15E. (xxxi) E1/2 of NW1/4 of Section 28 of T35N...

  1. 40 CFR 52.2581 - Significant deterioration of air quality.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... provisions for prevention of significant deterioration of air quality at 40 CFR 52.21 are applicable to the... 164 of the Clean Air Act and the provisions of 40 CFR 52.21(g), those parcels of the Forest County... T35N R15E. (xxx) E1/2 of Section 28 of T35N R15E. (xxxi) E1/2 of NW1/4 of Section 28 of T35N...

  2. 40 CFR 52.2581 - Significant deterioration of air quality.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... provisions for prevention of significant deterioration of air quality at 40 CFR 52.21 are applicable to the... 164 of the Clean Air Act and the provisions of 40 CFR 52.21(g), those parcels of the Forest County... T35N R15E. (xxx) E1/2 of Section 28 of T35N R15E. (xxxi) E1/2 of NW1/4 of Section 28 of T35N...

  3. 40 CFR 52.2581 - Significant deterioration of air quality.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... provisions for prevention of significant deterioration of air quality at 40 CFR 52.21 are applicable to the... 164 of the Clean Air Act and the provisions of 40 CFR 52.21(g), those parcels of the Forest County... T35N R15E. (xxx) E1/2 of Section 28 of T35N R15E. (xxxi) E1/2 of NW1/4 of Section 28 of T35N...

  4. 40 CFR 52.2581 - Significant deterioration of air quality.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... provisions for prevention of significant deterioration of air quality at 40 CFR 52.21 are applicable to the... 164 of the Clean Air Act and the provisions of 40 CFR 52.21(g), those parcels of the Forest County... T35N R15E. (xxx) E1/2 of Section 28 of T35N R15E. (xxxi) E1/2 of NW1/4 of Section 28 of T35N...

  5. Method for combining information from white matter fiber tracking and gray matter parcellation.

    PubMed

    Park, Hae-Jeong; Kubicki, Marek; Westin, Carl-Fredrik; Talos, Ion-Florin; Brun, Anders; Peiper, Steve; Kikinis, Ron; Jolesz, Ference A; McCarley, Robert W; Shenton, Martha E

    2004-09-01

    We introduce a method for combining fiber tracking from diffusion-tensor (DT) imaging with cortical gray matter parcellation from structural high-spatial-resolution 3D spoiled gradient-recalled acquisition in the steady state images. We applied this method to a tumor case to determine the impact of the tumor on white matter architecture. We conclude that this new method for combining structural and DT imaging data is useful for understanding cortical connectivity and the localization of fiber tracts and their relationship with cortical anatomy and brain abnormalities.

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

    PubMed Central

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

    2014-01-01

    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. PMID:25173414

  7. 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.

  8. Highly constrained entry trajectory generation

    NASA Astrophysics Data System (ADS)

    Xie, Yu; Liu, Luhua; Tang, Guojian; Zheng, Wei

    2013-07-01

    An entry trajectory planning algorithm that generates flyable trajectories satisfying waypoints, no-fly zones, and other path and terminal constraints is presented. The algorithm tactically divides the entry trajectory into the initial and glide phases. In the initial phase, a nominal angle of attack and a constant bank angle are used to generate the 3-D trajectory. In the glide phase, a planner is developed based on the evolved acceleration guidance logic for entry (EAGLE). The planner is divided into a longitudinal sub-planner and a lateral sub-planner. For longitudinal planning, the drag-energy profile is represented as five piecewise linear functions of the normalized non-conventional energy to make it consistent with both the desired trajectory length and the lateral maneuverability required to meet waypoint and no-fly zone constraints. The longitudinal sub-planner determines the magnitude of the bank angle, whereas the lateral sub-planner determines the appropriate sign of the bank angle for passing waypoints, avoiding no-fly zones, and minimizing the final heading error. The longitudinal and lateral sub-planners are iteratively employed until all path and terminal constraints are satisfied. Then, a tracker is employed to follow both the reference drag acceleration and the heading angle profiles to generate a feasible closed-loop entry trajectory. The approach is tested using the Common Aero Vehicle model. Simulations demonstrate that the generated trajectories can pass the predetermined waypoints, avoid no-fly zones, and achieve the desired target conditions within allowable tolerances.

  9. 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…

  10. 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.

  11. 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.

  12. Functional Connectivity-Based Parcellation of Amygdala Using Self-Organized Mapping: A Data Driven Approach

    PubMed Central

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

    2013-01-01

    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. PMID:23418140

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

    PubMed

    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

  14. Expert System For Flexible Palletizing Of Mixed Size And Weight Parcels

    NASA Astrophysics Data System (ADS)

    Mazouz, A. Kader; Shell, Richard L.; Hall, E. L.

    1988-02-01

    Stacking boxes of mixed size and weight is a tedious task requiring intelligence. It requires the ability to recognize that boxes are available to be stacked, the recognition of different box types, the selection of a grasping point for picking up the box and most importantly, a determination of where to stack the box on a partially loaded pallet. The purpose of this paper is to describe an expert system for determining how to stack a set of mixed size and weight boxes and provide control information to a robot to perform actual palletizing. A prototype system has been developed using an expert programming language and an industrial robot work cell. The system has been tested with actual food parcels weighing up to 50 pounds and performs very well. The formation of flat regions is one of the many rules implemented in the expert system. The system also works at speeds comparable to human speeds. The study demonstrates, in large measure, the feasibility of the use of expert system AI techniques and industrial robots for palletizing mixed size weight parcels in a general workhousing application.

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

    PubMed

    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.

  16. 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

  17. 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.

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

    PubMed

    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. PMID:27272166

  19. 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.

  20. 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.

  1. Quantum trajectories of superconducting qubits

    NASA Astrophysics Data System (ADS)

    Weber, Steven J.; Murch, Kater W.; Kimchi-Schwartz, Mollie E.; Roch, Nicolas; Siddiqi, Irfan

    2016-08-01

    In this review, we discuss recent experiments that investigate how the quantum sate of a superconducting qubit evolves during measurement. We provide a pedagogical overview of the measurement process, when the qubit is dispersively coupled to a microwave frequency cavity, and the qubit state is encoded in the phase of a microwave tone that probes the cavity. A continuous measurement record is used to reconstruct the individual quantum trajectories of the qubit state, and quantum state tomography is performed to verify that the state has been tracked accurately. Furthermore, we discuss ensembles of trajectories, time-symmetric evolution, two-qubit trajectories, and potential applications in measurement-based quantum error correction. xml:lang="fr"

  2. Impact of the resolution of brain parcels on connectome-wide association studies in fMRI.

    PubMed

    Bellec, Pierre; Benhajali, Yassine; Carbonell, Felix; Dansereau, Christian; Albouy, Geneviève; Pelland, Maxime; Craddock, Cameron; Collignon, Oliver; Doyon, Julien; Stip, Emmanuel; Orban, Pierre

    2015-12-01

    A recent trend in functional magnetic resonance imaging is to test for association of clinical disorders with every possible connection between selected brain parcels. We investigated the impact of the resolution of functional brain parcels, ranging from large-scale networks to local regions, on a mass univariate general linear model (GLM) of connectomes. For each resolution taken independently, the Benjamini-Hochberg procedure controlled the false-discovery rate (FDR) at nominal level on realistic simulations. However, the FDR for tests pooled across all resolutions could be inflated compared to the FDR within resolution. This inflation was severe in the presence of no or weak effects, but became negligible for strong effects. We thus developed an omnibus test to establish the overall presence of true discoveries across all resolutions. Although not a guarantee to control the FDR across resolutions, the omnibus test may be used for descriptive analysis of the impact of resolution on a GLM analysis, in complement to a primary analysis at a predefined single resolution. On three real datasets with significant omnibus test (schizophrenia, congenital blindness, motor practice), markedly higher rate of discovery were obtained at low resolutions, below 50, in line with simulations showing increase in sensitivity at such resolutions. This increase in discovery rate came at the cost of a lower ability to localize effects, as low resolution parcels merged many different brain regions together. However, with 30 or more parcels, the statistical effect maps were biologically plausible and very consistent across resolutions. These results show that resolution is a key parameter for GLM-connectome analysis with FDR control, and that a functional brain parcellation with 30 to 50 parcels may lead to an accurate summary of full connectome effects with good sensitivity in many situations.

  3. Cost trajectories for cancer patients

    PubMed Central

    Wodchis, W.P.; Arthurs, E.; Khan, A.I.; Gandhi, S.; MacKinnon, M.; Sussman, J.

    2016-01-01

    Background Health care spending is known to be highly skewed, with a small subset of the population consuming a disproportionate amount of health care resources. Patients with cancer are high-cost users because of high incremental health care costs for treatment and the growing prevalence of cancer. The objectives of the present study included characterizing cancer-patient trajectories by cost, and identifying the patient and health system characteristics associated with high health system costs after cancer treatment. Methods This retrospective cohort study identified Ontario adults newly diagnosed with cancer between 1 April 2009 and 30 September 2010. Costs of health care use before, during, and after cancer episodes were used to develop trajectories of care. Descriptive analyses examined differences between the trajectories in terms of clinical and health system characteristics, and a logistic regression approach identified predictors of being a high-cost user after a cancer episode. Results Ten trajectories were developed based on whether patients were high- or low-cost users before and after their cancer episode. The most common trajectory represented patients who were low-cost in the year before cancer, survived treatment, and continued to be low-cost in the year after cancer (31.4%); stage ii cancer of the male genital system was the most common diagnosis within that trajectory. Regression analyses identified increases in age and in multimorbidity and low continuity of care as the strongest predictors of high-cost status after cancer. Conclusions Findings highlight an opportunity to proactively identify patients who might transition to high-cost status after cancer treatment and to remediate that transition. PMID:26985150

  4. 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.

  5. 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.

  6. 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,...

  7. 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,...

  8. 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…

  9. 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…

  10. Interplanetary Trajectories, Encke Method (ITEM)

    NASA Technical Reports Server (NTRS)

    Whitlock, F. H.; Wolfe, H.; Lefton, L.; Levine, N.

    1972-01-01

    Modified program has been developed using improved variation of Encke method which avoids accumulation of round-off errors and avoids numerical ambiguities arising from near-circular orbits of low inclination. Variety of interplanetary trajectory problems can be computed with maximum accuracy and efficiency.

  11. 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.

  12. 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.

  13. Available Instruments for Analyzing Molecular Dynamics Trajectories.

    PubMed

    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

  14. Experimental nonlocal and surreal Bohmian trajectories.

    PubMed

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

    2016-02-01

    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.

  15. 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

  16. Experimental nonlocal and surreal Bohmian trajectories.

    PubMed

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

    2016-02-01

    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

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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

    ... From the Federal Register Online via the Government Publishing Office 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 Indian Community of Michigan AGENCY: Bureau of Indian...

  2. 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…

  3. 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...

  4. A Monte Carlo Study Investigating the Impact of Item Parceling Strategies on Parameter Estimates and Their Standard Errors in CFA

    ERIC Educational Resources Information Center

    Alhija, Fadia Nasser-Abu; Wisenbaker, Joseph

    2006-01-01

    A simulation study was conducted to examine the effect of item parceling on confirmatory factor analysis parameter estimates and their standard errors at different levels of sample size, number of indicators per factor, size of factor structure/pattern coefficients, magnitude of interfactor correlations, and variations in item-level data…

  5. 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

    ... 27 Alcohol, Tobacco Products and Firearms 2 2014-04-01 2014-04-01 false Delivery of tobacco products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY...

  6. 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

    ... 27 Alcohol, Tobacco Products and Firearms 2 2013-04-01 2013-04-01 false Delivery of tobacco products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY...

  7. 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

    ... 27 Alcohol, Tobacco Products and Firearms 2 2012-04-01 2011-04-01 true Delivery of tobacco products, and cigarette papers and tubes for export by parcel post. 44.226 Section 44.226 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY...

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

    PubMed Central

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

    2009-01-01

    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 (parceling, latent scoring, and shortening) to modeling lengthy scales in SEM were reviewed and evaluated. A hypothetical population model was simulated containing two exogenous constructs with 14 indicators each and an endogenous construct with four indicators. The simulation generated data sets with varying numbers of response options, two types of distributions, factor loadings ranging from low to high, and sample sizes ranging from small to moderate. The population model was varied to incorporate one of the following: (1) single parcels, (2) various parcels as indicators of two exogenous constructs, (3) latent scores as observed exogenous variables, and (4) four and six of individual items as indicators of two exogenous constructs. The dependent variables evaluated were biases in the covariance and partial covariance population parameters. Biases in these parameters were found to be minimal under the following conditions: (1) when parcels of indicators of five response options were used as indicators of two latent exogenous constructs; (2) when latent scores were used as observed variables at sample sizes above 100 and with indicators that were relatively less skewed in the case of dichotomous indicators; and (3) when four or six individual items with high or diverse factor loadings were used as indicators of two exogenous constructs. These findings provided guidelines for resolving the inconsistency of findings from applying various approaches to empirical data. PMID:20514149

  9. 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.

  10. 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...

  11. 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...

  12. 78 FR 56242 - Notice of Realty Action: Competitive Sale of 28 Parcels of Public Land in Clark County, NV

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-12

    ... Bureau of Land Management [LLNVS00560 L58530000 EU0000 241A; N-78190 et al.; 13-08807; MO 4500053642; TAS: 14X5232] Notice of Realty Action: Competitive Sale of 28 Parcels of Public Land in Clark County, NV AGENCY: Bureau of Land Management, Interior. ACTION: Notice of Realty Action. SUMMARY: The Bureau of...

  13. 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...

  14. 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...

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    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.

  16. 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.

  17. Trajectory NG: portable, compressed, general molecular dynamics trajectories.

    PubMed

    Spångberg, Daniel; Larsson, Daniel S D; van der Spoel, David

    2011-10-01

    We present general algorithms for the compression of molecular dynamics trajectories. The standard ways to store MD trajectories as text or as raw binary floating point numbers result in very large files when efficient simulation programs are used on supercomputers. Our algorithms are based on the observation that differences in atomic coordinates/velocities, in either time or space, are generally smaller than the absolute values of the coordinates/velocities. Also, it is often possible to store values at a lower precision. We apply several compression schemes to compress the resulting differences further. The most efficient algorithms developed here use a block sorting algorithm in combination with Huffman coding. Depending on the frequency of storage of frames in the trajectory, either space, time, or combinations of space and time differences are usually the most efficient. We compare the efficiency of our algorithms with each other and with other algorithms present in the literature for various systems: liquid argon, water, a virus capsid solvated in 15 mM aqueous NaCl, and solid magnesium oxide. We perform tests to determine how much precision is necessary to obtain accurate structural and dynamic properties, as well as benchmark a parallelized implementation of the algorithms. We obtain compression ratios (compared to single precision floating point) of 1:3.3-1:35 depending on the frequency of storage of frames and the system studied. PMID:21267752

  18. Reentry trajectory optimization and control

    NASA Astrophysics Data System (ADS)

    Strohmaier, P.; Kiefer, A.; Burkhardt, D.; Horn, K.

    1990-06-01

    There are several possible methods to increase the cross range capability of a winged reentry vehicle, for instance, skip trajectories, a powered cruise phase, or high lift/drag ratio flight. However, most of these alternative descent strategies have not yet been investigated sufficiently with respect to aero-thermodynamic effects and the design of the thermal protection system. This problem is treated by two different means. First, a nominal reentry trajectory is generated based on a phase concept, and then the same problem is again solved using a numerical optimization code to determine the control functions. The nominal reentry trajectory design presented first subdivides the total reentry trajectory into several segments with partially constant control/state parameters such as maximum heat flux and deceleration. The optimal conditions for a given segment can then be selected. In contrast, the parameterized optimization code selects the control functions freely. Both approaches consider a mass point simulation which uses realistic model assumptions for atmosphere, earth and gravity. Likewise, both approaches satisfy all flight regime limitations and boundary conditions such as thermal constraints throughout the flight path and specified speed and altitude at the final time. For the optimization of high cross reentry trajectories the cross range per total absorbed heat represents an appropriate cost function. The optimization code delivers quite a different flight strategy than that usually generated by the nominal reentry design program, first flying longer along the temperature boundary at highest possible angle of attack (AOAs) (utilizing higher average turn rates), and afterwards performing flare-dive segments to reduce heat flux and to increase range. Finally, the aspect of guiding the nominal or optimized reentry trajectory during a cross range flight is considered. The vertical guidance is performed with both angles of attack and roll angle control. The

  19. 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.

  20. 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.

  1. Trajectory optimization for the National Aerospace Plane

    NASA Technical Reports Server (NTRS)

    Lu, Ping

    1993-01-01

    The objective of this second phase research is to investigate the optimal ascent trajectory for the National Aerospace Plane (NASP) from runway take-off to orbital insertion and address the unique problems associated with the hypersonic flight trajectory optimization. The trajectory optimization problem for an aerospace plane is a highly challenging problem because of the complexity involved. Previous work has been successful in obtaining sub-optimal trajectories by using energy-state approximation and time-scale decomposition techniques. But it is known that the energy-state approximation is not valid in certain portions of the trajectory. This research aims at employing full dynamics of the aerospace plane and emphasizing direct trajectory optimization methods. The major accomplishments of this research include the first-time development of an inverse dynamics approach in trajectory optimization which enables us to generate optimal trajectories for the aerospace plane efficiently and reliably, and general analytical solutions to constrained hypersonic trajectories that has wide application in trajectory optimization as well as in guidance and flight dynamics. Optimal trajectories in abort landing and ascent augmented with rocket propulsion and thrust vectoring control were also investigated. Motivated by this study, a new global trajectory optimization tool using continuous simulated annealing and a nonlinear predictive feedback guidance law have been under investigation and some promising results have been obtained, which may well lead to more significant development and application in the near future.

  2. 14 CFR 417.207 - Trajectory analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Trajectory analysis. 417.207 Section 417... 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, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Trajectory analysis. 417.207 Section 417... 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. Analytical solutions to constrained hypersonic flight trajectories

    NASA Technical Reports Server (NTRS)

    Lu, Ping

    1993-01-01

    The flight trajectory of aerospace vehicles subject to a class of path constraints is considered. The constrained dynamics is shown to be a natural two-time-scale system. Asymptotic analytical solutions are obtained. Problems of trajectory optimization and guidance can be dramatically simplified with these solutions. Applications in trajectory design for an aerospace plane strongly support the theoretical development.

  5. Analytical solutions to constrained hypersonic flight trajectories

    NASA Technical Reports Server (NTRS)

    Lu, Ping

    1992-01-01

    The flight trajectory of aerospace vehicles subject to a class of path constraints is considered. The constrained dynamics is shown to be a natural two-time-scale system. Asymptotic analytical solutions are obtained. Problems of trajectory optimization and guidance can be dramatically simplified with these solutions. Applications in trajectory design for an aerospace plane strongly support the theoretical development.

  6. 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…

  7. 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.

  8. Techniques for shuttle trajectory optimization

    NASA Technical Reports Server (NTRS)

    Edge, E. R.; Shieh, C. J.; Powers, W. F.

    1973-01-01

    The application of recently developed function-space Davidon-type techniques to the shuttle ascent trajectory optimization problem is discussed along with an investigation of the recently developed PRAXIS algorithm for parameter optimization. At the outset of this analysis, the major deficiency of the function-space algorithms was their potential storage problems. Since most previous analyses of the methods were with relatively low-dimension problems, no storage problems were encountered. However, in shuttle trajectory optimization, storage is a problem, and this problem was handled efficiently. Topics discussed include: the shuttle ascent model and the development of the particular optimization equations; the function-space algorithms; the operation of the algorithm and typical simulations; variable final-time problem considerations; and a modification of Powell's algorithm.

  9. Geometric diffusion of quantum trajectories.

    PubMed

    Yang, Fan; Liu, Ren-Bao

    2015-07-16

    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.

  10. 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.

  11. 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.

  12. Perioperative cognitive trajectory in adults.

    PubMed

    Nadelson, M R; Sanders, R D; Avidan, M S

    2014-03-01

    Approximately a quarter of a billion people undergo surgery every year hoping that the operation will alleviate symptoms, cure diseases, and improve quality-of-life. A concern has arisen that, despite the benefits of surgery, elderly patients might suffer neurological injury from surgery and general anaesthesia leading to persistent cognitive decline. However, many studies of postoperative cognition have had methodological weaknesses, including lack of suitable control groups, dissociation of cognitive outcomes from surgical outcomes, sub-optimal statistical techniques, and absence of longitudinal preoperative cognitive assessments. Emerging evidence suggests that after early cognitive decline, most patients return to their preoperative cognitive trajectories within 3 months of surgery; some even experience subsequent cognitive improvement. In this review, we summarize the scientific literature on perioperative cognition. We propose that the most important determinants of the postoperative cognitive trajectory are the preoperative cognitive trajectory, the success of the surgery, and events in the perioperative period. Postoperative complications, ongoing inflammation, and chronic pain are probably modifiable risk factors for persistent postoperative cognitive decline. When surgery is successful with minimal perioperative physiological perturbations, elderly patients can expect cognition to follow its preoperative course. Furthermore, when surgery alleviates symptoms and enhances quality-of-life, postoperative cognitive improvement is a possible and desirable outcome.

  13. Bohmian trajectories of Airy packets

    NASA Astrophysics Data System (ADS)

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-01

    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.

  14. 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.

  15. 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

  16. 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.

  17. Integrated trajectory and control analysis for generic hypersonic vehicles

    NASA Technical Reports Server (NTRS)

    Hattis, Philip D.; Malchow, Harvey L.; Shaughnessy, John; Chowdhry, Rajiv S.

    1991-01-01

    A tool which supports integrated assessment of air-breathing hypersonic vehicle trajectory management and control strategy has been developed by Hattis and Malchow (1991). Using a two-point boundary value problem solution technique, the tool can construct 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 strategy is also formulated to construct preliminary trajectory and control history representations with less computational burden than required for the overall flight profile assessment. A tabulated example hypersonic vehicle model has been used to demonstrate the integrated analysis methodology. To assure good numerical behavior when the algorithm uses tabulated model data, a multidimensional cubic spline curve smoothing routine has been developed. A dynamic-pressure-constrained, near-fuel-optimal trajectory was computed to provide examples of information that the methodology can provide. Previously unspecified propulsive discontinuities were located, flight regimes demanding rapid attitude changes were identified, available and closed-loop controller authority was ascertained, and inadequacies in vehicle and specific subsystem model representations were determined.

  18. Integrated trajectory and control analysis for generic hypersonic vehicles

    NASA Astrophysics Data System (ADS)

    Hattis, Philip D.; Malchow, Harvey L.; Shaughnessy, John; Chowdhry, Rajiv S.

    1991-12-01

    A tool which supports integrated assessment of air-breathing hypersonic vehicle trajectory management and control strategy has been developed by Hattis and Malchow (1991). Using a two-point boundary value problem solution technique, the tool can construct 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 strategy is also formulated to construct preliminary trajectory and control history representations with less computational burden than required for the overall flight profile assessment. A tabulated example hypersonic vehicle model has been used to demonstrate the integrated analysis methodology. To assure good numerical behavior when the algorithm uses tabulated model data, a multidimensional cubic spline curve smoothing routine has been developed. A dynamic-pressure-constrained, near-fuel-optimal trajectory was computed to provide examples of information that the methodology can provide. Previously unspecified propulsive discontinuities were located, flight regimes demanding rapid attitude changes were identified, available and closed-loop controller authority was ascertained, and inadequacies in vehicle and specific subsystem model representations were determined.

  19. 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

  20. Relationship between back trajectories and tropospheric trace gas concentrations in rural Virginia

    NASA Astrophysics Data System (ADS)

    Moy, Leslie A.; Dickerson, Russell R.; Ryan, William F.

    The day-to-day variations in mixing ratios of trace gases carbon monoxide (CO), ozone (O 3), and total reactive nitrogen (NO y) at rural Shenandoah National Park, VA, are explained to a large extent by the circulation of the air prior to arrival. Using 48 h back trajectories, we analyzed the variability of air quality. In one approach, we separated the highest 2% and lowest 32% of NO y mixing ratio, and compared composite sets of back trajectories for each group. In the "dirty" group, the air passed over the industrialized Midwest more frequently than in the "clean" group (51 vs 23%). When air from the industrialized Midwest was clean, its travel had often been interrupted by convective clouds that mix pollutants vertically and wash out soluble species. Radar summaries show that 80% of the clean trajectories from the northwest passed through areas of convection. In a second approach, we clustered daily trajectories into groups with similar circulation patterns. The cleanest air was associated with rapid westerly flow and strong subsidence, or with origins in the less-populated areas to the south and southeast of the Park. The highest levels of photochemical smog were not associated with stagnation and local emissions, or even transport from the nearby Washington metropolitan area. The dirtiest days resulted from slow air circulation and transport from the industrialized Midwest (as seen from the first approach).

  1. Convolutional Sparse Coding for Trajectory Reconstruction.

    PubMed

    Zhu, Yingying; Lucey, Simon

    2015-03-01

    Trajectory basis Non-Rigid Structure from Motion (NRSfM) refers to the process of reconstructing the 3D trajectory of each point of a non-rigid object from just their 2D projected trajectories. Reconstruction relies on two factors: (i) the condition of the composed camera & trajectory basis matrix, and (ii) whether the trajectory basis has enough degrees of freedom to model the 3D point trajectory. These two factors are inherently conflicting. Employing a trajectory basis with small capacity has the positive characteristic of reducing the likelihood of an ill-conditioned system (when composed with the camera) during reconstruction. However, this has the negative characteristic of increasing the likelihood that the basis will not be able to fully model the object's "true" 3D point trajectories. In this paper we draw upon a well known result centering around the Reduced Isometry Property (RIP) condition for sparse signal reconstruction. RIP allow us to relax the requirement that the full trajectory basis composed with the camera matrix must be well conditioned. Further, we propose a strategy for learning an over-complete basis using convolutional sparse coding from naturally occurring point trajectory corpora to increase the likelihood that the RIP condition holds for a broad class of point trajectories and camera motions. Finally, we propose an l1 inspired objective for trajectory reconstruction that is able to "adaptively" select the smallest sub-matrix from an over-complete trajectory basis that balances (i) and (ii). We present more practical 3D reconstruction results compared to current state of the art in trajectory basis NRSfM.

  2. 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.

  3. Photochemical trajectory modeling of ozone concentrations in Hong Kong.

    PubMed

    Cheng, H R; Saunders, S M; Guo, H; Louie, P K K; Jiang, F

    2013-09-01

    In this study, tropical cyclones over the East and South China Seas were found to be the most predominant weather conditions associated with the occurrence of high ozone (O3) episodes in Hong Kong in 2005-2009. A photochemical trajectory model coupled with Master Chemical Mechanism (MCM) was adapted to simulate the O3 concentrations during two O3 pollution episodes. The results agreed well with the observed data. A representative backward air mass trajectory was used to determine the contribution of each volatile organic compound (VOC) to the O3 levels. After taking into account both reactivity and mass emission of each VOC, 10 species were found to be the key O3 precursors in Hong Kong. Further analysis identified solvent related products accounting for 70% of the modeled O3 concentration in Hong Kong. The results highlight the importance of considering together reactivity and source sector emissions in developing targeted VOC reduction for O3 abatement strategies.

  4. 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.

  5. MESODIF-II. Variable Trajectory Plume Segment Model

    SciTech Connect

    Powell, D.C.; Hegley, H.L.; Fox, T.D.

    1986-06-01

    MESODIF-II which embodies a variable trajectory plume segment atmospheric transport model, is designed to predict normalized air concentrations and deposition of radioactive, but otherwise non-reactive, effluents released from one or two levels over the same position in an xy-plane. In such a model, calculated particle trajectories vary as synoptic scale wind varies. At all sampling times, the particles are connected to form a segmented plume centerline. The lateral and vertical dimensions of the plume are determined by a parameterization of turbulence scale diffusion. The impetus for the development of this model arose from the need of the United States Nuclear Regulatory Commission to assess radiological effects resulting from routine nuclear power reactor operations, as outlined in United States Nuclear Regulatory Guide 1.111.

  6. 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.

  7. 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. PMID:11863640

  8. 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.

  9. 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

  10. 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.

  11. 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

  12. Optimization of Supersonic Transport Trajectories

    NASA Technical Reports Server (NTRS)

    Ardema, Mark D.; Windhorst, Robert; Phillips, James

    1998-01-01

    This paper develops a near-optimal guidance law for generating minimum fuel, time, or cost fixed-range trajectories for supersonic transport aircraft. The approach uses a choice of new state variables along with singular perturbation techniques to time-scale decouple the dynamic equations into multiple equations of single order (second order for the fast dynamics). Application of the maximum principle to each of the decoupled equations, as opposed to application to the original coupled equations, avoids the two point boundary value problem and transforms the problem from one of a functional optimization to one of multiple function optimizations. It is shown that such an approach produces well known aircraft performance results such as minimizing the Brequet factor for minimum fuel consumption and the energy climb path. Furthermore, the new state variables produce a consistent calculation of flight path angle along the trajectory, eliminating one of the deficiencies in the traditional energy state approximation. In addition, jumps in the energy climb path are smoothed out by integration of the original dynamic equations at constant load factor. Numerical results performed for a supersonic transport design show that a pushover dive followed by a pullout at nominal load factors are sufficient maneuvers to smooth the jump.

  13. 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

  14. 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. PMID:27598550

  15. 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.

  16. Unruh effect for general trajectories

    SciTech Connect

    Obadia, N.; Milgrom, M.

    2007-03-15

    We consider two-level detectors coupled to a scalar field and moving on arbitrary trajectories in Minkowski space-time. We first derive a generic expression for the response function using a (novel) regularization procedure based on the Feynman prescription that is explicitly causal, and we compare it to other expressions used in the literature. We then use this expression to study, analytically and numerically, the time dependence of the response function in various nonstationarity situations. We show that, generically, the response function decreases like a power in the detector's level spacing, E, for high E. It is only for stationary worldlines that the response function decays faster than any power law, in keeping with the known exponential behavior for some stationary cases. Under some conditions the (time-dependent) response function for a nonstationary worldline is well approximated by the value of the response function for a stationary worldline having the same instantaneous acceleration, torsion, and hypertorsion. While we cannot offer general conditions for this to apply, we discuss special cases; in particular, the low-energy limit for linear space trajectories.

  17. Connectivity-based whole brain dual parcellation by group ICA reveals tract structures and decreased connectivity in schizophrenia.

    PubMed

    Wu, Lei; Calhoun, Vince D; Jung, Rex E; Caprihan, Arvind

    2015-11-01

    Mapping brain connectivity based on neuroimaging data is a promising new tool for understanding brain structure and function. In this methods paper, we demonstrate that group independent component analysis (GICA) can be used to perform a dual parcellation of the brain based on its connectivity matrix (cmICA). This dual parcellation consists of a set of spatially independent source maps, and a corresponding set of paired dual maps that define the connectivity of each source map to the brain. These dual maps are called the connectivity profiles of the source maps. Traditional analysis of connectivity matrices has been used previously for brain parcellation, but the present method provides additional information on the connectivity of these segmented regions. In this paper, the whole brain structural connectivity matrices were calculated on a 5 mm(3) voxel scale from diffusion imaging data based on the probabilistic tractography method. The effect of the choice of the number of components (30 and 100) and their stability were examined. This method generated a set of spatially independent components that are consistent with the canonical brain tracts provided by previous anatomic descriptions, with the high order model yielding finer segmentations. The corpus-callosum example shows how this method leads to a robust parcellation of a brain structure based on its connectivity properties. We applied cmICA to study structural connectivity differences between a group of schizophrenia subjects and healthy controls. The connectivity profiles at both model orders showed similar regions with reduced connectivity in schizophrenia patients. These regions included forceps major, right inferior fronto-occipital fasciculus, uncinate fasciculus, thalamic radiation, and corticospinal tract. This paper provides a novel unsupervised data-driven framework that summarizes the information in a large global connectivity matrix and tests for brain connectivity differences. It has the

  18. Localization and quantification of intramuscular damage using statistical parametric mapping and skeletal muscle parcellation

    PubMed Central

    Fouré, Alexandre; Le Troter, Arnaud; Guye, Maxime; Mattei, Jean-Pierre; Bendahan, David; Gondin, Julien

    2015-01-01

    In the present study, we proposed an original and robust methodology which combines the spatial normalization of skeletal muscle images, the statistical parametric mapping (SPM) analysis and the use of a specific parcellation in order to accurately localize and quantify the extent of skeletal muscle damage within the four heads of the quadriceps femoris. T2 maps of thigh muscles were characterized before, two (D2) and four (D4) days after 40 maximal isometric electrically-evoked contractions in 25 healthy young males. On the basis of SPM analysis of coregistrated T2 maps, the alterations were similarly detected at D2 and D4 in the superficial and distal regions of the vastus medialis (VM) whereas the proportion of altered muscle was higher in deep muscle regions of the vastus lateralis at D4 (deep: 35 ± 25%, superficial: 23 ± 15%) as compared to D2 (deep: 18 ± 13%, superficial: 17 ± 13%). The present methodology used for the first time on skeletal muscle would be of utmost interest to detect subtle intramuscular alterations not only for the diagnosis of muscular diseases but also for assessing the efficacy of potential therapeutic interventions and clinical treatment strategies. PMID:26689827

  19. 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. PMID:8119262

  20. 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.

  1. Volumetric and Correlational Implications of Brain Parcellation Method Selection: A 3-Way Comparison in the Frontal Lobes

    PubMed Central

    Cox, Simon R.; McKenzie, Tahlia I.; Aribisala, Benjamin S.; Royle, Natalie A.; MacPherson, Sarah E.; MacLullich, Alasdair M.J.; Bastin, Mark E.; Wardlaw, Joanna M.; Deary, Ian J.; Ferguson, Karen J.

    2016-01-01

    Objective The aims of this study were to compare distinct brain frontal lobe parcellation methods across 90 brain magnetic resonance imaging scans and examine their associations with cognition in older age. Methods Three parcellation methods (Manual, FreeSurfer, and Stereology) were applied to T1-weighted magnetic resonance imaging of 90 older men, aged ∼73 years. A measure of general fluid intelligence (gf) associated with dorsolateral frontal regions was also derived from a contemporaneous psychological test battery. Results Despite highly discordant raw volumes for the same nominal regions, Manual and FreeSurfer (but not Stereology) left dorsolateral measures were significantly correlated with gf (r > 0.22), whereas orbital and inferior lateral volumes were not, consistent with the hypothesized frontal localization of gf. Conclusions Individual differences in specific frontal lobe brain volumes—variously measured—show consistent associations with cognitive ability in older age. Importantly, differences in parcellation protocol for some regions that may impact the outcome of brain-cognition analyses are discussed. PMID:26466114

  2. 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.

  3. 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.

  4. Winding light beams along elliptical helical trajectories

    NASA Astrophysics Data System (ADS)

    Wen, Yuanhui; Chen, Yujie; Zhang, Yanfeng; Chen, Hui; Yu, Siyuan

    2016-07-01

    Conventional caustic methods in real or Fourier space produced accelerating optical beams only with convex trajectories. We developed a superposition caustic method capable of winding light beams along nonconvex trajectories. We ascertain this method by constructing a one-dimensional (1D) accelerating beam moving along a sinusoidal trajectory, and subsequently extending to two-dimensional (2D) accelerating beams along arbitrarily elliptical helical trajectories. We experimentally implemented the method with a compact and robust integrated optics approach by fabricating micro-optical structures on quartz glass plates to perform the spatial phase and amplitude modulation to the incident light, generating beam trajectories highly consistent with prediction. The theoretical and implementation methods can in principle be extended to the construction of accelerating beams with a wide variety of nonconvex trajectories, thereby opening up a route of manipulating light beams for fundamental research and practical applications.

  5. 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.

  6. Quantitative back-trajectory apportionment of sources of particulate sulfate at Big Bend National Park, TX

    NASA Astrophysics Data System (ADS)

    Gebhart, Kristi A.; Schichtel, Bret A.; Barna, Michael G.; Malm, William C.

    As part of the Big Bend Regional Aerosol and Visibility Observational (BRAVO) study, a quantitative back-trajectory-based receptor model, Trajectory Mass Balance (TrMB) was used to estimate source apportionment of particulate sulfur measured at Big Bend National Park, Texas, during July-October 1999. The model was exercised using a number of sets of trajectories generated by three different trajectory models, with three different sets of input gridded meteorology, and tracked for 5, 7, and 10 days back in time. The performance of the TrMB model with the different trajectory inputs was first evaluated against perfluorocarbon tracers and synthetically generated sulfate concentrations from a regional air quality model, both of which had known attributions. These tests were used to determine which trajectories were adequate for the TrMB modeling of measured sulfate concentrations, illustrated the magnitude of the daily uncertainties as compared to the uncertainties in the mean attributions, and demonstrated the value of a robust evaluation process. Depending on trajectories, mean sulfate source apportionment results were 39-50% from Mexico, 7-26% from the eastern US, 12-45% from Texas, and 3-25% from the western US. These ranges were inclusive of the best BRAVO attribution estimates for Mexico, Texas, and the western US, but TrMB underestimated the eastern US contribution as compared to the BRAVO best estimates.

  7. 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.

  8. 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

  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. An Operational Concept for Flying FMS Trajectories in Center and TRACON Airspace

    NASA Technical Reports Server (NTRS)

    Palmer, Everett; Williams, David; Prevot, Thomas; Romanhn, Stephan; Goka, Tsuyoshi; Smith, Nancy; Crane, Barry; Null, Cynthia (Technical Monitor)

    1998-01-01

    Current Flight Management Systems (FMS) do a good job of constructing and flying an optimal trajectory for a single aircraft. Unfortunately, flight crews are often unable to fly these FMS routes during arrivals at busy airports. The Center TRACON Automation System (CTAS) has been designed to aid Center and TRACON (Terminal Radar Approach Control) controllers in assigning runways, sequencing and vectoring all classes of aircraft. CTAS bases its advisories on trajectory predictions for arriving aircraft using algorithms very similar to those in airborne FMS systems. This paper presents near and far term operational concepts for how a ground ATM (air traffic management) automation system like CTAS could work more effectively with the airborne automation in FMS equipped aircraft. The concepts for a more compatible air-ground system include: 1) a common route databases for both CTAS and FMS; 2) datalink to downlink information on aircraft weight, final approach speed and trajectory intent and to uplink wind information; 3) new FMS functions to allow flight crews to easily update their FMS trajectory to match the trajectory suggested by the ground automation with voice clearances, and 4) in the far term, datalink to downlink user preferred trajectories and to uplink trajectory clearances in the terminal area. The paper analyses some of the human factors issues that may result in allowing aircraft to fly FMS routes during enroute descent and in the terminal area. A series of linked human in the loop flight deck and air traffic control simulations and a field test with the NASA 757 are being conducted at NASA's Ames and Langley Research Centers to address these issues and to evaluate the operational feasibility of these approaches to more efficient flight and increased airport throughput.

  12. 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.

  13. 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.

  14. 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.

  15. Catchment-scale hydrologic implications of parcel-level stormwater management (Ohio USA)

    NASA Astrophysics Data System (ADS)

    Shuster, William; Rhea, Lee

    2013-04-01

    SummaryThe effectiveness of stormwater management strategies is a key issue affecting decision making on urban water resources management, and so proper monitoring and analysis of pilot studies must be addressed before drawing conclusions. We performed a pilot study in the suburban Shepherd Creek watershed located in Cincinnati, Ohio to evaluate the practicality of voluntary incentives for stormwater quantity reduction on privately owned suburban properties. Stream discharge and precipitation were monitored 3 years before and after implementation of the stormwater management treatments. To implement stormwater control measures, we elicited the participation of citizen landowners with two successive reverse-auctions. Auctions were held in spring 2007, and 2008, resulting in the installation of 85 rain gardens and 174 rain barrels. We demonstrated an analytic process of increasing model flexibility to determine hydrologic effectiveness of stormwater management at the sub-catchment level. A significant albeit small proportion of total variance was explained by both the effects of study period (˜69%) and treatment-vs.-control (˜7%). Precipitation-discharge relationships were synthesized in estimated unit hydrographs, which were decomposed and components tested for influence of treatments. Analysis of unit hydrograph parameters showed a weakened correlation between precipitation and discharge, and support the output from the initial model that parcel-level green infrastructure added detention capacity to treatment basins. We conclude that retrofit management of stormwater runoff quantity with green infrastructure in a small suburban catchment can be successfully initiated with novel economic incentive programs, and that these measures can impart a small, but statistically significant decrease in otherwise uncontrolled runoff volume. Given consistent monitoring data and analysis, water resource managers can use our approach as a way to estimate actual effectiveness of

  16. 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.

  17. 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…

  18. 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.

  19. 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…

  20. Optimal transfer trajectories with intermediate velocity injection

    NASA Astrophysics Data System (ADS)

    Srivastava, T. N.; Nangia, A. K.

    An analytical optimization technique for spacecraft transfer trajectories is developed and demonstrated. The optimization criterion is defined as the minimum impulsive velocity change at initial, intermediate, and final points of the trajectory. Numerical results for earth-Mars transfer are presented in tables and graphs, and the case of injection at the initial point only is considered separately.

  1. 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…

  2. 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.

  3. 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.

  4. 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.

  5. Trajectories of delinquency and parenting styles.

    PubMed

    Hoeve, Machteld; Blokland, Arjan; Dubas, Judith Semon; Loeber, Rolf; Gerris, Jan R M; van der Laan, Peter H

    2008-02-01

    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 delinquency trajectories differing in both level and change in seriousness over time: a nondelinquent, minor persisting, moderate desisting, serious persisting, and serious desisting trajectory. More serious delinquents tended to more frequently engage in delinquency, and to report a higher proportion of theft. Proportionally, serious persistent delinquents were the most violent of all trajectory groups. Using cluster analysis we identified three parenting styles: authoritative, authoritarian (moderately supportive), and neglectful (punishing). Controlling for demographic characteristics and childhood delinquency, neglectful parenting was more frequent in moderate desisters, serious persisters, and serious desisters, suggesting that parenting styles differentiate non- or minor delinquents from more serious delinquents.

  6. 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 optimal trajectories of the aeroassisted flight experiment (AFE) spacecraft are analyzed in a three-dimensional space using the full system of six ODEs describing the atmospheric pass. The optimal trajectories are computed for two possible transfers: indirect ascent to a 178 NM perigee via a 197 NM apogee and direct ascent to a 178 NM apogee. For each transfer, two cases are investigated: (1) the bank angle is continuously variable, and (2) the trajectory is divided into segments along which the bank angle is constant. It is shown that the optimal trajectories for both cases coalesce into a two subarc trajectory, with the bank angle constant in each subarc. It is also shown that, during the atmospheric pass, the peak values of the changes of the orbital inclination and the longitude of the ascending node are nearly zero.

  7. Trajectories of Delinquency and Parenting Styles

    PubMed Central

    Blokland, Arjan; Dubas, Judith Semon; Loeber, Rolf; Gerris, Jan R. M.; van der Laan, Peter H.

    2007-01-01

    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 delinquency trajectories differing in both level and change in seriousness over time: a nondelinquent, minor persisting, moderate desisting, serious persisting, and serious desisting trajectory. More serious delinquents tended to more frequently engage in delinquency, and to report a higher proportion of theft. Proportionally, serious persistent delinquents were the most violent of all trajectory groups. Using cluster analysis we identified three parenting styles: authoritative, authoritarian (moderately supportive), and neglectful (punishing). Controlling for demographic characteristics and childhood delinquency, neglectful parenting was more frequent in moderate desisters, serious persisters, and serious desisters, suggesting that parenting styles differentiate non- or minor delinquents from more serious delinquents. PMID:17786548

  8. 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.

  9. 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

  10. 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

  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. 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.

  13. 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.

  14. Overlapped conic simulation of three-body trajectories

    NASA Technical Reports Server (NTRS)

    Wilson, S. W., Jr.

    1970-01-01

    Trajectory computation technique for three-body motion is based on analytical derivation and empirical validation of pseudostate theory. Application of technique yields ''overlapped conic'' trajectories with error magnitudes only 20 percent as great as those of patched conic trajectories.

  15. 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.

  16. A model for computing the trajectories of the conducting particles from waste printed circuit boards in corona electrostatic separators.

    PubMed

    Li, Jia; Lu, Hongzhou; Xu, Zhenming; Zhou, Yaohe

    2008-02-28

    A model for computing the trajectory of conducting particle from waste printed circuit board (PCB) scraps in corona electrostatic separator is established. Using analytical expression for computing non-uniformity of the electric field in the active zone of the separator and the differential method were used for computing the trajectories of conducting particles in the air, after detachment. The result shows that the trajectory of conducting particle can be computed under various initial parameters (R, r, L, alpha, U, n; rho, r0) by the computing model and the computing results have a good agreement with the actual separating process. This model offers a possible for designing the new corona electrostatic separator.

  17. 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.

  18. Direct optimization method for reentry trajectory design

    NASA Astrophysics Data System (ADS)

    Jallade, S.; Huber, P.; Potti, J.; Dutruel-Lecohier, G.

    The software package called `Reentry and Atmospheric Transfer Trajectory' (RATT) was developed under ESA contract for the design of atmospheric trajectories. It includes four software TOP (Trajectory OPtimization) programs, which optimize reentry and aeroassisted transfer trajectories. 6FD and 3FD (6 and 3 degrees of freedom Flight Dynamic) are devoted to the simulation of the trajectory. SCA (Sensitivity and Covariance Analysis) performs covariance analysis on a given trajectory with respect to different uncertainties and error sources. TOP provides the optimum guidance law of a three degree of freedom reentry of aeroassisted transfer (AAOT) trajectories. Deorbit and reorbit impulses (if necessary) can be taken into account in the optimization. A wide choice of cost function is available to the user such as the integrated heat flux, or the sum of the velocity impulses, or a linear combination of both of them for trajectory and vehicle design. The crossrange and the downrange can be maximized during reentry trajectory. Path constraints are available on the load factor, the heat flux and the dynamic pressure. Results on these proposed options are presented. TOPPHY is the part of the TOP software corresponding to the definition and the computation of the optimization problemphysics. TOPPHY can interface with several optimizes with dynamic solvers: TOPOP and TROPIC using direct collocation methods and PROMIS using direct multiple shooting method. TOPOP was developed in the frame of this contract, it uses Hermite polynomials for the collocation method and the NPSOL optimizer from the NAG library. Both TROPIC and PROMIS were developed by the DLR (Deutsche Forschungsanstalt fuer Luft und Raumfahrt) and use the SLSQP optimizer. For the dynamic equation resolution, TROPIC uses a collocation method with Splines and PROMIS uses a multiple shooting method with finite differences. The three different optimizers including dynamics were tested on the reentry trajectory of the

  19. Trajectory optimization for the national aerospace plane

    NASA Technical Reports Server (NTRS)

    Lu, Ping

    1993-01-01

    During the past six months the research objectives outlined in the last semi-annual report were accomplished. Specifically, these are: three-dimensional (3-D) fuel-optimal ascent trajectory of the aerospace plane and the effects of thrust vectoring control (TVC) on the fuel consumption and trajectory shaping were investigated; the maximum abort landing area (footprint) was studied; preliminary assessment of simultaneous design of the ascent trajectory and the vehicle configuration for the aerospace plane was also conducted. The work accomplished in the reporting period is summarized.

  20. 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.

  1. Renormalization Group Trajectories Between Two Fixed Points

    NASA Astrophysics Data System (ADS)

    Abdesselam, Abdelmalek

    2010-03-01

    We report on our recent rigorous construction of complete renormalization group trajectories between two fixed points for the three-dimensional phi-four model with modified propagator considered by Brydges, Mitter and Scoppola (BMS). These are discrete critical trajectories which connect the ultraviolet Gaussian fixed point to the nontrivial BMS infrared fixed point which is an analogue of the Wilson-Fisher fixed point. The renormalization group map is defined rigorously and nonperturbatively, without using the hierarchical approximation. The trajectories are constructed by a fixed point argument in a suitable Banach space of sequences, where one perturbs a nonlinear one-dimensional iteration.

  2. Nominal trajectories for the aeroassisted flight experiment

    NASA Technical Reports Server (NTRS)

    Miele, A.; Wang, T.

    1993-01-01

    The problem of generating good nominal trajectories is considered with particular reference to an AFE type spacecraft flying with constant angle of attack and variable angle of bank. A simulated GEO-to-LEO aeroassisted orbital transfer is considered. It is shown that, for fixed control, the AFE trajectory exhibits strong intrinsic instability in the longitudinal motion and near neutrality in the lateral motion, while stability can be artificially induced via feedback control, the effectiveness of a feedback control scheme depends on control margin availability. The AFE nominal trajectory must be chosen as a compromise between good performance and good control margin.

  3. 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.

  4. 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.

  5. 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)

  6. 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.

  7. Longitudinal Trajectories of Cigarette Smoking Following Rape

    PubMed Central

    Amstadter, Ananda B.; Resnick, Heidi S.; Nugent, Nicole R.; Acierno, Ron; Rheingold, Alyssa A.; Minhinnett, Robin; Kilpatrick, Dean G.

    2009-01-01

    Although prior research has identified increases in cigarette smoking following trauma exposure, no studies have examined longitudinal trajectories of smoking following rape. The present investigation identifies and characterizes longitudinal (< 3 months, 3-6 months, and > 6 months post-assault) trajectories of smoking (N = 152) following a rape in a sample of 268 sexual assault victims participating in a forensic medical exam. Further, we examine acute predictors of subsequent smoking trajectories. Of participants endorsing smoking post-rape, a two-class solution was identified, with the majority of participants (74.6%) evidencing moderate smoking with a slight decrease over time and remaining participants showing heavy smoking with a slight increase over time. Having sustained an injury, minority status, and post-exam distress all predicted subsequent smoking trajectory. PMID:19370699

  8. 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)

  9. 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.

  10. 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.

  11. Estimation of Flight Trajectories by Using GPS Data Measured in Airliner Cabin

    NASA Astrophysics Data System (ADS)

    Totoki, Hironori; Wickramasinghe, Navinda Kithmal; Hamada, Taturo; Miyazawa, Yoshikazu

    Flight trajectory of a passenger aircraft is critical for the research and development of future air traffic control system. Generally, though, flight data are closed to the public view. In this paper a simple method is introduced to estimate flight trajectories using a commercial GPS receiver at a cabin of an in-flight airplane and numerical weather data. Barometric pressure altitude and Mach number were evaluated at the study. Results prove that airplanes follow almost exactly the predetermined airway and cruising altitude. Maximum deviation was recorded only at a magnitude of several dozen meters.

  12. 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

  13. 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.

  14. Kinematic evaluation of virtual walking trajectories.

    PubMed

    Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

    2013-04-01

    Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories. PMID:23428452

  15. 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

  16. 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.

  17. Kinematic evaluation of virtual walking trajectories.

    PubMed

    Cirio, Gabriel; Olivier, Anne-Hélène; Marchal, Maud; Pettré, Julien

    2013-04-01

    Virtual walking, a fundamental task in Virtual Reality (VR), is greatly influenced by the locomotion interface being used, by the specificities of input and output devices, and by the way the virtual environment is represented. No matter how virtual walking is controlled, the generation of realistic virtual trajectories is absolutely required for some applications, especially those dedicated to the study of walking behaviors in VR, navigation through virtual places for architecture, rehabilitation and training. Previous studies focused on evaluating the realism of locomotion trajectories have mostly considered the result of the locomotion task (efficiency, accuracy) and its subjective perception (presence, cybersickness). Few focused on the locomotion trajectory itself, but in situation of geometrically constrained task. In this paper, we study the realism of unconstrained trajectories produced during virtual walking by addressing the following question: did the user reach his destination by virtually walking along a trajectory he would have followed in similar real conditions? To this end, we propose a comprehensive evaluation framework consisting on a set of trajectographical criteria and a locomotion model to generate reference trajectories. We consider a simple locomotion task where users walk between two oriented points in space. The travel path is analyzed both geometrically and temporally in comparison to simulated reference trajectories. In addition, we demonstrate the framework over a user study which considered an initial set of common and frequent virtual walking conditions, namely different input devices, output display devices, control laws, and visualization modalities. The study provides insight into the relative contributions of each condition to the overall realism of the resulting virtual trajectories.

  18. Framland parcels extraction from high-resolution remote sensing images based on the two-stage image classification

    NASA Astrophysics Data System (ADS)

    Liu, Guoying; Song, Xu; Lv, Jing

    2015-12-01

    It is difficult and boring for people to artificially extract farmland parcels from high resolution remote sensing images. Therefore, automatic methods are in the urgent need to release image interpreters from such a work as well as achieve accurate results. In the past years, although many researchers have made attempts to solve this problem by using different techniques and also produced some good results, they still cannot meet the demand of practical applications. In this paper, a farmland extraction method is proposed based on a new technique of two-stage image classification. The first stage aims at producing a map of farmland area by using the supervised iterative conditional mode (ICM), where a novel mixture posterior is proposed based on the tree-structured interpretation of certain complex landscapes, e.g., farmland and building area, and the Markov random field model (MRF) is also used to make use of spatial information between neighboring pixels. The second stage extracts the farmland parcels by using the Meanshift algorithm (MS) based on the hybrid of the original image and the texture image produced by the local binary pattern (LBP) method. We applied our method to a piece of aerial image in the urban area of Taizhou, China. The results show that the proposed method has an ability to produce more accurate results than the MS method.

  19. Decoding the Role of the Insula in Human Cognition: Functional Parcellation and Large-Scale Reverse Inference

    PubMed Central

    Yarkoni, Tal; Khaw, Mel Win; Sanfey, Alan G.

    2013-01-01

    Recent work has indicated that the insula may be involved in goal-directed cognition, switching between networks, and the conscious awareness of affect and somatosensation. However, these findings have been limited by the insula’s remarkably high base rate of activation and considerable functional heterogeneity. The present study used a relatively unbiased data-driven approach combining resting-state connectivity-based parcellation of the insula with large-scale meta-analysis to understand how the insula is anatomically organized based on functional connectivity patterns as well as the consistency and specificity of the associated cognitive functions. Our findings support a tripartite subdivision of the insula and reveal that the patterns of functional connectivity in the resting-state analysis appear to be relatively conserved across tasks in the meta-analytic coactivation analysis. The function of the networks was meta-analytically “decoded” using the Neurosynth framework and revealed that while the dorsoanterior insula is more consistently involved in human cognition than ventroanterior and posterior networks, each parcellated network is specifically associated with a distinct function. Collectively, this work suggests that the insula is instrumental in integrating disparate functional systems involved in processing affect, sensory-motor processing, and general cognition and is well suited to provide an interface between feelings, cognition, and action. PMID:22437053

  20. Heuristic approach to launch vehicle trajectory design

    NASA Astrophysics Data System (ADS)

    Kawakatsu, Yasuhiro; Yamada, Kazuyuki

    A heuristic method of designing the launch trajectory is proposed. The objective of our research is 'to search for the trajectory which can insert maximum payload into the target orbit, while satisfying all the given constraints'. Difficulties in achieving this goal come from the numerous design parameters and various constraints inherent to the trajectory design problem. The employed design methodology is based on numerical integration and heuristic search. By numerical integration, any type of constraints can be taken into account, and heuristic search can reduce the search space to a manageable level, which otherwise causes combinatorial explosion. We divide the period of time in launch operations into some phases, in each of which we integrate numerically the trajectory for every combination of variables related to that phase. The heuristic rule can reduce the number of combinations to be investigated in the phase, and the constraints can reduce the space of final condition of this phase, which results in the reduction of the search space of the initial conditions of the next phase. To estimate the effect of this methodology, we applied it to an example problem of the launch trajectory design of BS-3b satellite by H-1 rocket. Some simulation results are discussed, especially in terms of search space reduction and the features of the generated trajectories.

  1. 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.

  2. 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.

  3. Quantum trajectories based on the weak value

    NASA Astrophysics Data System (ADS)

    Mori, Takuya; Tsutsui, Izumi

    2015-04-01

    The notion of the trajectory of an individual particle is strictly inhibited in quantum mechanics because of the uncertainty principle. Nonetheless, the weak value, which has been proposed as a novel and measurable quantity definable to any quantum observable, can offer a possible description of trajectory on account of its statistical nature. In this paper, we explore the physical significance provided by this "weak trajectory" by considering various situations where interference takes place simultaneously with the observation of particles, that is, in prototypical quantum situations for which no classical treatment is available. These include the double slit experiment and Lloyd's mirror, where in the former case it is argued that the real part of the weak trajectory describes an average over the possible classical trajectories involved in the process, and that the imaginary part is related to the variation of interference. It is shown that this average interpretation of the weak trajectory holds universally under the complex probability defined from the given transition process. These features remain essentially unaltered in the case of Lloyd's mirror where interference occurs with a single slit.

  4. Quantum tunneling dynamics using hydrodynamic trajectories

    NASA Astrophysics Data System (ADS)

    Bittner, Eric R.

    2000-06-01

    In this paper we compute quantum trajectories arising from Bohm's causal description of quantum mechanics. Our computational methodology is based upon a finite-element moving least-squares method (MWLS) presented recently by Wyatt and co-workers [Lopreore and Wyatt, Phys. Rev. Lett. 82, 5190 (1999)]. This method treats the "particles" in the quantum Hamilton-Jacobi equation as Lagrangian fluid elements that carry the phase, S, and density, ρ, required to reconstruct the quantum wave function. Here, we compare results obtained via the MWLS procedure to exact results obtained either analytically or by numerical solution of the time-dependent Schrödinger equation. Two systems are considered: first, dynamics in a harmonic well and second, tunneling dynamics in a double well potential. In the case of tunneling in the double well potential, the quantum potential acts to lower the barrier, separating the right- and left-hand sides of the well, permitting trajectories to pass from one side to another. However, as probability density passes from one side to the other, the effective barrier begins to rise and eventually will segregate trajectories in one side from the other. We note that the MWLS trajectories exhibited long time stability in the purely harmonic cases. However, this stability was not evident in the barrier crossing dynamics. Comparisons to exact trajectories obtained via wave packet calculations indicate that the MWLS trajectories tend to underestimate the effects of constructive and destructive interference effects.

  5. Trajectory-profile-guided single molecule tracking for assignment of one-dimensional diffusion trajectories.

    PubMed

    Robben, Kevin C; Tran-Ba, Khanh-Hoa; Ito, Takashi; Higgins, Daniel A

    2014-11-01

    A variety of algorithms exist for optical single molecule tracking in two and three dimensions. One general class of algorithms employs cost-functionals to link the individual fluorescent spots, produced by a molecule in sequential video frames, into trajectories. This method has also been used to track one-dimensional (1D) molecular motions for relatively low diffusion rates (i.e., D < 1 μm(2)/s). At high diffusion rates, the cost-functional approach often fails to accurately reproduce 1D trajectories, particularly when the molecules are closely spaced. In this paper, we present a new algorithm called trajectory-profile-guided (TPG) tracking that is designed specifically for 1D trajectories. TPG tracking involves an initial search for one-dimensionally aligned fluorescent spots (i.e., candidate molecules). Qualifying candidates are subsequently identified and linked into trajectories based on several criteria. We test the TPG algorithm's accuracy and precision against cost-functional based tracking using both simulated and experimental video data. The results show that TPG tracking more accurately reproduces the actual 1D trajectories, particularly at higher diffusion rates. TPG tracking is also shown to produce longer trajectories and more accurate estimates of trajectory aspect ratios (i.e., their dimensionality), molecular diffusion coefficients, and order parameters for aligned 1D trajectories over a wide range of diffusion coefficients.

  6. 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

  7. Using tax parcels to select a location-based sample: an illustration that examines residents' awareness of sex offenders in neighborhoods.

    PubMed

    Craun, Sarah W; Freisthler, Bridget

    2008-08-01

    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 mail surveys to target residents in varied geographic areas. A provided example demonstrates how researchers obtained a sample of respondents living within one tenth of a mile of multiple registered sex offenders. The challenges of using tax parcels to obtain addresses for apartments and mobile home parks are also explored.

  8. 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

  9. 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 ...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Trajectory optimization for a National Launch System vehicle

    NASA Technical Reports Server (NTRS)

    Chen, Eugene S.; Boelitz, Frederick W.; Sullivan, Jeanne M.

    1993-01-01

    A trajectory design process is presented for a proposed National Launch System (NLS) vehicle configuration. A software trajectory planner was developed to generate near optimal pitch plane trajectories for variable mission plans, variable launch site selections, and last minute wind conditions at the time of launch. In addition, the trajectory planner performs in-flight near optimal trajectory redesign in the event of an engine-out or unexpected wind dispersions. The trajectory planner iteratively simulates trial trajectories defined by variables corresponding to a parameterized trajectory shape. The trajectory planner optimizes these trajectory parameters according to the fuel used to realize the trajectories. For prelaunch scenarios, the trajectory planner generated near optimal trajectories of consistent fuel performance irrespective of the winds encountered at the launch site. In-flight trajectory redesigns were also shown to be effective in fulfilling the mission plan and preserving the structural integrity of the vehicle. The in-flight redesign results indicate that closed-loop guidance in the early stages of ascent is highly effective in accommodating engine failures or wind dispersions. All trajectory designs were verified using a 6DOF simulation with flight controllers.

  17. Modified point mass trajectory simulation for base-burn projectiles

    NASA Astrophysics Data System (ADS)

    Lieske, R. F.; Danberg, J. E.

    1992-03-01

    An addition to the Modified Point Mass Trajectory Model for Rocket-Assisted Projectiles is presented for the exterior ballistic simulation of base-burn projectiles. The addition models the change in aerodynamic base-drag based on the change in base pressure due to the base-burn motor's ejection of hot gas into the wake of the projectile. The mass flow rate of the remaining fuel of the base-burn motor is modeled as a function of the instantaneous projectile spin rate and atmospheric air pressure. HAWK Doppler radar data collected at Yuma Proving Ground, Arizona, for the 155mm, M1864 base-burn projectile were used to verify the modeling approach for a variety of test conditions.

  18. Parental Work Schedules and Children's Cognitive Trajectories.

    PubMed

    Han, Wen-Jui; Fox, Liana E

    2011-10-01

    Previous work has shown an association between mothers' nonstandard work schedules and children's well-being. We built on this research by examining the relationship between parental shift work and children's reading and math trajectories from age 5/6 to 13/14. Using data (N=7,105) from the National Longitudinal Survey of Youth and growth curve modeling, we found that children's math and reading trajectories were related to parents' type of nonstandard shifts (i.e., evening, night, or variable). We found that having a mother who worked more years at a night shift was associated with lower reading scores, having a mother work more years at evening or night shifts was associated with reduced math trajectories, and having a father work more years at an evening shift was associated with reduced math scores. Mediation tests suggest that eating meals together, parental knowledge about children's whereabouts, and certain after-school activities might help explain these results.

  19. Trajectory optimization for the National Aerospace Plane

    NASA Technical Reports Server (NTRS)

    Lu, Ping

    1992-01-01

    The primary objective of this research is to develop an efficient and robust trajectory optimization tool for the optimal ascent problem of the National Aerospace Plane (NASP). This report is organized in the following order to summarize the complete work: Section two states the formulation and models of the trajectory optimization problem. An inverse dynamics approach to the problem is introduced in Section three. Optimal trajectories corresponding to various conditions and performance parameters are presented in Section four. A midcourse nonlinear feedback controller is developed in Section five. Section six demonstrates the performance of the inverse dynamics approach and midcourse controller during disturbances. Section seven discusses rocket assisted ascent which may be beneficial when orbital altitude is high. Finally, Section eight recommends areas of future research.

  20. Analysis of Petal Rotation Trajectory Characteristics

    NASA Technical Reports Server (NTRS)

    Anderson, Rodney L.; Campagnola, Stefano; Buffington, Brent B.

    2014-01-01

    In this study, the characteristics of petal rotation trajectories are explored in both the two-body and circular restricted three-body problem (CRTBP) models. Petal rotation trajectories alternate long and short resonances of different kinds to rotate the line of apsides. They are typically computed using the patched conic model, and they are used in a number of different missions and mission concepts including Cassini, JUICE, and Europa mission concepts. Petal rotation trajectories are first analyzed here using the patched conic model to quantify their characteristics and search for cases with fast rotation of the line of apsides. When they are computed in the CRTBP, they are unstable periodic orbits with corresponding stable and unstable manifolds. The characteristics of these orbits are explored from a dynamical systems perspective in the second phase of the study.

  1. Parallel solver for trajectory optimization search directions

    NASA Technical Reports Server (NTRS)

    Psiaki, M. L.; Park, K. H.

    1992-01-01

    A key algorithmic element of a real-time trajectory optimization hardware/software implementation is presented, the search step solver. This is one piece of an algorithm whose overall goal is to make nonlinear trajectory optimization fast enough to provide real-time commands during guidance of a vehicle such as an aeromaneuvering orbiter or the National Aerospace Plane. Many methods of nonlinear programming require the solution of a quadratic program (QP) at each iteration to determine the search step. In the trajectory optimization case, the QP has a special dynamic programming structure. The algorithm exploits this special structure with a divide- and conquer type of parallel implementation. The algorithm solves a (p.N)-stage problem on N processors in O(p + log2 N) operations. The algorithm yields a factor of 8 speed-up over the fastest known serial algorithm when solving a 1024-stage test problem on 32 processors.

  2. 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

  3. Robot trajectories comparison: a statistical approach.

    PubMed

    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, FM(2) and WaveFront, using different environments, robots, and local planners. PMID:25525618

  4. 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.

  5. Model based trajectory planning using preview

    NASA Technical Reports Server (NTRS)

    Hayward, Vincent; Daneshmend, Laeeque; Nilakantan, Ajit

    1988-01-01

    The control of manipulators is seen here as a two-level process. A method is described to convert information available at the programming level into trajectories suitable to be tracked by a servo control system. The goal of the servo is to absorb the unmodeled dynamics. Tracking accuracy will depend mainly on the acceleration demand of the nominal trajectory setpoint, in particular, the actuator output demand must remain bounded. Our scheme adaptively takes into consideration at the trajectory computation level the dynamics of the underlying system, dynamically available information acquired through sensors, various types of constraints, such as path accuracy, and manipulator optimization. This scheme is meant to be implemented on-line, to drive mechanical systems such as manipulators. It is developed in the context of a multi-manipulator programming and control environment for space applications developed as part of a collaborative effort between McGill University and the Jet Propulsion Laboratory.

  6. Robot trajectories comparison: a statistical approach.

    PubMed

    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, FM(2) and WaveFront, using different environments, robots, and local planners.

  7. Optimization of aircraft trajectories through severe microbursts

    NASA Technical Reports Server (NTRS)

    Psiaki, Mark L.

    1987-01-01

    A method of defining performance envelopes for aircraft microburst penetration is being developed. A trajectory is computed for a given aircraft/control law configuration and given microburst parameters (either a downdraft or a head/tailwind type microburst). The maximum deviation from the nominal altitude is recorded for that trajectory. Then the microburst parameters are varied, and the process is repeated. Thus a three dimensional plot of maximum altitude deviation versus microburst range scale and intensity is generated. Finally, a certain maximum altitude deviation, say 50 feet, is defined as the safe penetration limit. Then the 50 foot level contour becomes the performance limit for safe operation as a function of microburst intensity and range. Control inputs from deterministic trajectory optimization are used in the above described calculations to define the maximal performance limit. These limits provide targets for the designer of practical control laws.

  8. Quantum trajectory phase transitions in the micromaser.

    PubMed

    Garrahan, Juan P; Armour, Andrew D; Lesanovsky, Igor

    2011-08-01

    We study the dynamics of the single-atom maser, or micromaser, by means of the recently introduced method of thermodynamics of quantum jump trajectories. We find that the dynamics of the micromaser displays multiple space-time phase transitions, i.e., phase transitions in ensembles of quantum jump trajectories. This rich dynamical phase structure becomes apparent when trajectories are classified by dynamical observables that quantify dynamical activity, such as the number of atoms that have changed state while traversing the cavity. The space-time transitions can be either first order or continuous, and are controlled not just by standard parameters of the micromaser but also by nonequilibrium "counting" fields. We discuss how the dynamical phase behavior relates to the better known stationary-state properties of the micromaser. PMID:21928957

  9. 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…

  10. Characterization of the temporo-parietal junction by combining data-driven parcellation, complementary connectivity analyses, and functional decoding

    PubMed Central

    Bzdok, Danilo; Langner, Robert; Schilbach, Leonhard; Jakobs, Oliver; Roski, Christian; Caspers, Svenja; Laird, Angela R.; Fox, Peter T.; Zilles, Karl; Eickhoff, Simon B.

    2016-01-01

    The right temporo-parietal junction (RTPJ) is consistently implicated in two cognitive domains, attention and social cognitions. We conducted multi-modal connectivity-based parcellation to investigate potentially separate functional modules within RTPJ implementing this cognitive dualism. Both task-constrained meta-analytic coactivation mapping and task-free resting-state connectivity analysis independently identified two distinct clusters within RTPJ, subsequently characterized by network mapping and functional forward/reverse inference. Coactivation mapping and resting-state correlations revealed that the anterior cluster increased neural activity concomitantly with a midcingulate–motor–insular network, functionally associated with attention, and decreased neural activity concomitantly with a parietal network, functionally associated with social cognition and memory retrieval. The posterior cluster showed the exact opposite association pattern. Our data thus suggest that RTPJ links two antagonistic brain networks processing external versus internal information. PMID:23689016

  11. 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

  12. 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

  13. 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.

  14. 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.

  15. Human action recognition by extracting motion trajectories

    NASA Astrophysics Data System (ADS)

    Fu, Yuwen; Yang, Shangpeng

    2015-07-01

    This paper proposes a novel human action recognition framework named Hidden Markov Model (HMM) based Hybrid Event Probability Sequence (HEPS), which can recognize unlabeled actions from videos. First, motion trajectories are effectively extracted using the centers of moving objects. Secondly, the HEPS is constructed using the trajectories and represents different human actions. Finally, the improved Particle Swarm Optimization (PSO) with inertia weight is introduced to recognize human actions using HMM. The proposed methods are evaluated on UCF Human Action Dataset and achieve 76.67% accurate rate. The comparative experiments results demonstrate that the HMM got superior results with HEPS and PSO.

  16. 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.

  17. 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

  18. 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

  19. Flight Test Results: CTAS Cruise/Descent Trajectory Prediction Accuracy for En route ATC Advisories

    NASA Technical Reports Server (NTRS)

    Green, S.; Grace, M.; Williams, D.

    1999-01-01

    The Center/TRACON Automation System (CTAS), under development at NASA Ames Research Center, is designed to assist controllers with the management and control of air traffic transitioning to/from congested airspace. This paper focuses on the transition from the en route environment, to high-density terminal airspace, under a time-based arrival-metering constraint. Two flight tests were conducted at the Denver Air Route Traffic Control Center (ARTCC) to study trajectory-prediction accuracy, the key to accurate Decision Support Tool advisories such as conflict detection/resolution and fuel-efficient metering conformance. In collaboration with NASA Langley Research Center, these test were part of an overall effort to research systems and procedures for the integration of CTAS and flight management systems (FMS). The Langley Transport Systems Research Vehicle Boeing 737 airplane flew a combined total of 58 cruise-arrival trajectory runs while following CTAS clearance advisories. Actual trajectories of the airplane were compared to CTAS and FMS predictions to measure trajectory-prediction accuracy and identify the primary sources of error for both. The research airplane was used to evaluate several levels of cockpit automation ranging from conventional avionics to a performance-based vertical navigation (VNAV) FMS. Trajectory prediction accuracy was analyzed with respect to both ARTCC radar tracking and GPS-based aircraft measurements. This paper presents detailed results describing the trajectory accuracy and error sources. Although differences were found in both accuracy and error sources, CTAS accuracy was comparable to the FMS in terms of both meter-fix arrival-time performance (in support of metering) and 4D-trajectory prediction (key to conflict prediction). Overall arrival time errors (mean plus standard deviation) were measured to be approximately 24 seconds during the first flight test (23 runs) and 15 seconds during the second flight test (25 runs). The major

  20. 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.

  1. EIVAN - AN INTERACTIVE ORBITAL TRAJECTORY PLANNING TOOL

    NASA Technical Reports Server (NTRS)

    Brody, A. R.

    1994-01-01

    The Interactive Orbital Trajectory planning Tool, EIVAN, is a forward looking interactive orbit trajectory plotting tool for use with Proximity Operations (operations occurring within a one kilometer sphere of the space station) and other maneuvers. The result of vehicle burns on-orbit is very difficult to anticipate because of non-linearities in the equations of motion governing orbiting bodies. EIVAN was developed to plot resulting trajectories, to provide a better comprehension of orbital mechanics effects, and to help the user develop heuristics for onorbit mission planning. EIVAN comprises a worksheet and a chart from Microsoft Excel on a Macintosh computer. The orbital path for a user-specified time interval is plotted given operator burn inputs. Fuel use is also calculated. After the thrust parameters (magnitude, direction, and time) are input, EIVAN plots the resulting trajectory. Up to five burns may be inserted at any time in the mission. Twenty data points are plotted for each burn and the time interval can be varied to accommodate any desired time frame or degree of resolution. Since the number of data points for each burn is constant, the mission duration can be increased or decreased by increasing or decreasing the time interval. The EIVAN program runs with Microsoft's Excel for execution on a Macintosh running Macintosh OS. A working knowledge of Excel is helpful, but not imperative, for interacting with EIVAN. The program was developed in 1989.

  2. 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. PMID:27078486

  3. 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.

  4. 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....

  5. 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....

  6. 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....

  7. 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.

  8. Empirical Model for Predicting Rockfall Trajectory Direction

    NASA Astrophysics Data System (ADS)

    Asteriou, Pavlos; Tsiambaos, George

    2016-03-01

    A methodology for the experimental investigation of rockfall in three-dimensional space is presented in this paper, aiming to assist on-going research of the complexity of a block's response to impact during a rockfall. An extended laboratory investigation was conducted, consisting of 590 tests with cubical and spherical blocks made of an artificial material. The effects of shape, slope angle and the deviation of the post-impact trajectory are examined as a function of the pre-impact trajectory direction. Additionally, an empirical model is proposed that estimates the deviation of the post-impact trajectory as a function of the pre-impact trajectory with respect to the slope surface and the slope angle. This empirical model is validated by 192 small-scale field tests, which are also presented in this paper. Some important aspects of the three-dimensional nature of rockfall phenomena are highlighted that have been hitherto neglected. The 3D space data provided in this study are suitable for the calibration and verification of rockfall analysis software that has become increasingly popular in design practice.

  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. Generation of NEP heliocentric trajectory data

    NASA Technical Reports Server (NTRS)

    Horsewood, J. L.; Brice, K. B.

    1972-01-01

    A study, designed to generate representative nuclear electric propulsion data for rendezvous missions to the comet Encke using the variational calculus program HILTOP, is presented. Other purposes of the study include a comparison of the HILTOP data with equivalent data generated with QUICKTOP program and to propose approaches for storing and subsequently accessing the optimum trajectory and performance data in the QUICKLY program.

  11. 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.

  12. Phylogeny and the inference of evolutionary trajectories.

    PubMed

    Hancock, Lillian; Edwards, Erika J

    2014-07-01

    Most important organismal adaptations are not actually single traits, but complex trait syndromes that are evolutionarily integrated into a single emergent phenotype. Two alternative photosynthetic pathways, C4 photosynthesis and crassulacean acid metabolism (CAM), are primary plant adaptations of this sort, each requiring multiple biochemical and anatomical modifications. Phylogenetic methods are a promising approach for teasing apart the order of character acquisition during the evolution of complex traits, and the phylogenetic placement of intermediate phenotypes as sister taxa to fully optimized syndromes has been taken as good evidence of an 'ordered' evolutionary trajectory. But how much power does the phylogenetic approach have to detect ordered evolution? This study simulated ordered and unordered character evolution across a diverse set of phylogenetic trees to understand how tree size, models of evolution, and sampling efforts influence the ability to detect an evolutionary trajectory. The simulations show that small trees (15 taxa) do not contain enough information to correctly infer either an ordered or unordered trajectory, although inference improves as tree size and sampling increases. However, even when working with a 1000-taxon tree, the possibility of inferring the incorrect evolutionary model (type I/type II error) remains. Caution is needed when interpreting the phylogenetic placement of intermediate phenotypes, especially in small lineages. Such phylogenetic patterns can provide a line of evidence for the existence of a particular evolutionary trajectory, but they should be coupled with other types of data to infer the stepwise evolution of a complex character trait.

  13. 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.

  14. Parental Work Schedules and Children's Cognitive Trajectories

    ERIC Educational Resources Information Center

    Han, Wen-Jui; Fox, Liana E.

    2011-01-01

    Previous work has shown an association between mothers' nonstandard work schedules and children's well-being. We built on this research by examining the relationship between parental shift work and children's reading and math trajectories from age 5-6 to 13-14. Using data (N = 7,105) from the National Longitudinal Survey of Youth and growth-curve…

  15. 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…

  16. 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…

  17. 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…

  18. Skip entry trajectory planning and guidance

    NASA Astrophysics Data System (ADS)

    Brunner, Christopher William

    A numerical predictor-corrector (NPC) method for trajectory planning and closed-loop guidance of low lift-to-drag (L/D) ratio vehicles during the skip entry phase of a lunar-return mission is presented. The strategy calls for controlling the trajectory by modulation of the magnitude of the vehicle's bank angle. The magnitude of the bank angle used in the skip phase is determined by satisfying the downrange requirement to the landing site. The problem is formulated as a nonlinear univariate root-finding problem. Full three degree of freedom (3DOF) nonlinear trajectory dynamics are included to achieve high accuracy of the landing prediction. In addition, the proposed approach automatically yields a direct entry trajectory when the downrange is such that a skip entry is no longer necessary. The same algorithm repeatedly applied on-board in every guidance cycle realizes closed-loop guidance in the skip entry phase. A number of issues are identified and addressed that are critical in closed-loop implementations. Extensive 3DOF dispersion simulations are performed to evaluate the performance of the proposed approach, and the results demonstrate very reliable and robust performance of the algorithm in highly stressful dispersed conditions. Comparison is made between the proposed algorithm and an earlier skip algorithm developed for the Apollo space program. It is shown that the proposed algorithm is superior to the Apollo algorithm especially when used for entries with long downranges.

  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. 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.

  1. 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

  2. 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.

  3. Air Abrasion

    MedlinePlus

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  4. 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...

  5. Trajectories of Marital Conflict Across the Life Course: Predictors and Interactions With Marital Happiness Trajectories.

    PubMed

    Kamp Dush, Claire M; Taylor, Miles G

    2012-03-01

    Using typologies outlined by Gottman and Fitzpatrick as well as institutional and companionate models of marriage, the authors conducted a latent class analysis of marital conflict trajectories using 20 years of data from the Marital Instability Over the Life Course study. Respondents were in one of three groups: high, medium (around the mean), or low conflict. Several factors predicted conflict trajectory group membership; respondents who believed in lifelong marriage and shared decisions equally with their spouse were more likely to report low and less likely to report high conflict. The conflict trajectories were intersected with marital happiness trajectories to examine predictors of high and low quality marriages. A stronger belief in lifelong marriage, shared decision making, and husbands sharing a greater proportion of housework were associated with an increased likelihood of membership in a high happiness, low conflict marriage, and a decreased likelihood of a low marital happiness group.

  6. 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.

  7. 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…

  8. 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.

  9. 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. PMID:24574929

  10. 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

  11. 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.

  12. 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.

  13. Design and implementation of an air monitoring program in support of a brownfields redevelopment program

    SciTech Connect

    Maisel, B.E.; Hunt, G.T.; Devaney, R.J. Jr.; Gauvin, M.R.

    1998-12-31

    EPA`s Brownfields Economic Redevelopment Initiative has sparked renewal of industrial and commercial parcels otherwise idled or under-utilized because of real or perceived environmental contamination. In certain cases, restoring such parcels to productive economic use requires a redevelopment effort protective of human health and welfare through minimizing offsite migration of environmental contaminants during cleanup, demolition and remediation activities. To support these objectives, an air monitoring program is often required as an integral element of a comprehensive brownfields redevelopment effort. This paper presents a strategic framework for design and execution of an ambient air monitoring program in support of a brownfields remediation effort ongoing in Lawrence, MA. Based on site characterization, the program included sample collection and laboratory analysis of ambient air samples for polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDDs/PCDFs), total suspended particulate (TSP), inhalable particulate (PM10), and lead. The program included four monitoring phases, identified as background, wintertime, demolition/remediation and post-demolition. Air sampling occurred over a 16 month period during 1996--97, during which time nine sampling locations were utilized to produce approximately 1,500 ambient air samples. Following strict data review and validation procedures, ambient air data interpretation focused on the following: evaluation of upwind/downwind sample pairs, comparison of ambient levels to existing regulatory standards, relation of ambient levels to data reported in the open literature, and, determination of normal seasonal variations in existing background burden, comparison of ambient levels measured during site activity to background levels.

  14. Developmental Trajectories of Childhood Obesity and Risk Behaviors in Adolescence

    ERIC Educational Resources Information Center

    Huang, David Y. C.; Lanza, H. Isabella; Wright-Volel, Kynna; Anglin, M. Douglas

    2013-01-01

    Using group-based trajectory modeling, this study examined 5156 adolescents from the child sample of the 1979 National Longitudinal Survey of Youth to identify developmental trajectories of obesity from ages 6-18 and evaluate associations of such trajectories with risk behaviors and psychosocial health in adolescence. Four distinctive obesity…

  15. Psychosocial Correlates of Smoking Trajectories Among Urban African American Adolescents

    ERIC Educational Resources Information Center

    Fergus, Stevenson; Zimmerman, Marc A.; Caldwell, Cleopatra H.

    2005-01-01

    Little is known of smoking trajectories or of the correlates of smoking trajectories among African American youth. Ninth-grade African American adolescents (n = 566) were interviewed in Year 1 and then were subsequently interviewed annually for 3 additional years. Five trajectories of cigarette smokers were identified: abstainers,…

  16. Optical Trajectories and the Informational Basis of Fly Ball Catching

    ERIC Educational Resources Information Center

    Marken, Richard S.

    2005-01-01

    D. M. Shaffer and M. K. McBeath (see record 2002-02027-006) plotted the optical trajectories of uncatchable fly balls and concluded that linear optical trajectory is the informational basis of the actions taken to catch these balls. P. McLeod, N. Reed, and Z. Dienes (see record 2002-11140-016) replotted these trajectories in terms of changes in…

  17. Conditions for Young Infants' Failure to Perceive Trajectory Continuity

    ERIC Educational Resources Information Center

    Bremner, J. Gavin; Johnson, Scott P.; Slater, Alan; Mason, Uschi; Cheshire, Andrea; Spring, Joanne

    2007-01-01

    When viewing an event in which an object moves behind an occluder on part of its trajectory, 4-month-old infants perceive the trajectory as continuous only when time or distance out of sight is short. Little is known, however, about the conditions under which young infants perceive trajectories to be discontinuous. In the present studies we focus…

  18. Direct NOE simulation from long MD trajectories.

    PubMed

    Chalmers, G; Glushka, J N; Foley, B L; Woods, R J; Prestegard, J H

    2016-04-01

    A software package, MD2NOE, is presented which calculates Nuclear Overhauser Effect (NOE) build-up curves directly from molecular dynamics (MD) trajectories. It differs from traditional approaches in that it calculates correlation functions directly from the trajectory instead of extracting inverse sixth power distance terms as an intermediate step in calculating NOEs. This is particularly important for molecules that sample conformational states on a timescale similar to molecular reorientation. The package is tested on sucrose and results are shown to differ in small but significant ways from those calculated using an inverse sixth power assumption. Results are also compared to experiment and found to be in reasonable agreement despite an expected underestimation of water viscosity by the water model selected. PMID:26826977

  19. Direct NOE simulation from long MD trajectories

    NASA Astrophysics Data System (ADS)

    Chalmers, G.; Glushka, J. N.; Foley, B. L.; Woods, R. J.; Prestegard, J. H.

    2016-04-01

    A software package, MD2NOE, is presented which calculates Nuclear Overhauser Effect (NOE) build-up curves directly from molecular dynamics (MD) trajectories. It differs from traditional approaches in that it calculates correlation functions directly from the trajectory instead of extracting inverse sixth power distance terms as an intermediate step in calculating NOEs. This is particularly important for molecules that sample conformational states on a timescale similar to molecular reorientation. The package is tested on sucrose and results are shown to differ in small but significant ways from those calculated using an inverse sixth power assumption. Results are also compared to experiment and found to be in reasonable agreement despite an expected underestimation of water viscosity by the water model selected.

  20. Monotone viable trajectories for functional differential inclusions

    NASA Astrophysics Data System (ADS)

    Haddad, Georges

    This paper is a study on functional differential inclusions with memory which represent the multivalued version of retarded functional differential equations. The main result gives a necessary and sufficient equations. The main result gives a necessary and sufficient condition ensuring the existence of viable trajectories; that means trajectories remaining in a given nonempty closed convex set defined by given constraints the system must satisfy to be viable. Some motivations for this paper can be found in control theory where F( t, φ) = { f( t, φ, u)} uɛU is the set of possible velocities of the system at time t, depending on the past history represented by the function φ and on a control u ranging over a set U of controls. Other motivations can be found in planning procedures in microeconomics and in biological evolutions where problems with memory do effectively appear in a multivalued version. All these models require viability constraints represented by a closed convex set.