WorldWideScience

Sample records for average travel speed

  1. Near surface spatially averaged air temperature and wind speed determined by acoustic travel time tomography

    Directory of Open Access Journals (Sweden)

    Armin Raabe

    2001-03-01

    Full Text Available Acoustic travel time tomography is presented as a possibility for remote monitoring of near surface airtemperature and wind fields. This technique provides line-averaged effective sound speeds changing with temporally and spatially variable air temperature and wind vector. The effective sound speed is derived from the travel times of sound signals which propagate at defined paths between different acoustic sources and receivers. Starting with the travel time data a tomographic algorithm (Simultaneous Iterative Reconstruction Technique, SIRT is used to calculate area-averaged air temperature and wind speed. The accuracy of the experimental method and the tomographic inversion algorithm is exemplarily demonstrated for one day without remarkable differences in the horizontal temperature field, determined by independent in situ measurements at different points within the measuring field. The differences between the conventionally determined air temperature (point measurement and the air temperature determined by tomography (area-averaged measurement representative for the area of the measuring field 200m x 260m were below 0.5 K for an average of 10 minutes. The differences obtained between the wind speed measured at a meteorological mast and calculated from acoustic measurements are not higher than 0.5 ms-1 for the same averaging time. The tomographically determined area-averaged distribution of air temperature (resolution 50 m x 50 m can be used to estimate the horizontal gradient of air temperature as a pre-condition to detect horizontal turbulent fluxes of sensible heat.

  2. Wildlife speed cameras: measuring animal travel speed and day range using camera traps

    NARCIS (Netherlands)

    Rowcliffe, J.M.; Jansen, P.A.; Kays, R.; Kranstauber, B.; Carbone, C.

    2016-01-01

    Travel speed (average speed of travel while active) and day range (average speed over the daily activity cycle) are behavioural metrics that influence processes including energy use, foraging success, disease transmission and human-wildlife interactions, and which can therefore be applied to a range

  3. Wildlife speed cameras: measuring animal travel speed and day range using camera traps

    OpenAIRE

    Rowcliffe, J. M.; Jansen, P A; Kays, R.; Kranstauber, B.; C. Carbone

    2016-01-01

    Travel speed (average speed of travel while active) and day range (average speed over the daily activity cycle) are behavioural metrics that influence processes including energy use, foraging success, disease transmission and human-wildlife interactions, and which can therefore be applied to a range of questions in ecology and conservation. These metrics are usually derived from telemetry or direct observations. Here, we describe and validate an entirely new alternative approach, using camera...

  4. Freeway travel speed calculation model based on ETC transaction data.

    Science.gov (United States)

    Weng, Jiancheng; Yuan, Rongliang; Wang, Ru; Wang, Chang

    2014-01-01

    Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and presented the data preprocess procedure. Then, a dual-level travel speed calculation model was established under different levels of sample sizes. In order to ensure a sufficient sample size, ETC data of different enter-leave toll plazas pairs which contain more than one road segment were used to calculate the travel speed of every road segment. The reduction coefficient α and reliable weight θ for sample vehicle speed were introduced in the model. Finally, the model was verified by the special designed field experiments which were conducted on several freeways in Beijing at different time periods. The experiments results demonstrated that the average relative error was about 6.5% which means that the freeway travel speed could be estimated by the proposed model accurately. The proposed model is helpful to promote the level of the freeway operation monitoring and the freeway management, as well as to provide useful information for the freeway travelers. PMID:25580107

  5. A constant travel time budget? In search for explanations for an increase in average travel time

    OpenAIRE

    Wee, B.; Rietveld, P.; Meurs, H

    2002-01-01

    Recent research suggests that during the past decades the average travel time of the Dutch population has probably increased. However, different data sources show different levels of increase. Possible causes of the increase in average travel time are presented here. Increased incomes have probably resulted in an increase in both costs and benefits of travel. The increase in travel time may also be due to benefits having increased more rapidly than costs. Costs may even have decreased due to ...

  6. A constant travel time budget? In search for explanations for an increase in average travel time

    OpenAIRE

    Rietveld, P.; Wee, van, B.

    2002-01-01

    Recent research suggests that during the past decades the average travel time of the Dutch population has probably increased. However, different datasources show different levels of increase. Possible causes of the increase in average travel time are presented here. Increased incomes have probablyresulted in an increase in both costs and benefits of travel. The increase in travel time may also be due to benefits having increased more rapidly than costs. Costs may even have decreased due to th...

  7. A constant travel time budget? In search for explanations for an increase in average travel time

    NARCIS (Netherlands)

    Rietveld, P.; Wee, van B.

    2002-01-01

    Recent research suggests that during the past decades the average travel time of the Dutch population has probably increased. However, different datasources show different levels of increase. Possible causes of the increase in average travel time are presented here. Increased incomes have probablyre

  8. Floating Car Data Based Nonparametric Regression Model for Short-Term Travel Speed Prediction

    Institute of Scientific and Technical Information of China (English)

    WENG Jian-cheng; HU Zhong-wei; YU Quan; REN Fu-tian

    2007-01-01

    A K-nearest neighbor (K-NN) based nonparametric regression model was proposed to predict travel speed for Beijing expressway. By using the historical traffic data collected from the detectors in Beijing expressways, a specically designed database was developed via the processes including data filtering, wavelet analysis and clustering. The relativity based weighted Euclidean distance was used as the distance metric to identify the K groups of nearest data series. Then, a K-NN nonparametric regression model was built to predict the average travel speeds up to 6 min into the future. Several randomly selected travel speed data series,collected from the floating car data (FCD) system, were used to validate the model. The results indicate that using the FCD, the model can predict average travel speeds with an accuracy of above 90%, and hence is feasible and effective.

  9. Speed ot travelling waves in reaction-diffusion equations

    CERN Document Server

    Benguria, R D; Méndez, V

    2002-01-01

    Reaction diffusion equations arise in several problems of population dynamics, flame propagation and others. In one dimensional cases the systems may evolve into travelling fronts. Here we concentrate on a reaction diffusion equation which arises as a simple model for chemotaxis and present results for the speed of the travelling fronts. (Author)

  10. Freeway Travel Speed Calculation Model Based on ETC Transaction Data

    OpenAIRE

    Jiancheng Weng; Rongliang Yuan; Ru Wang; Chang Wang

    2014-01-01

    Real-time traffic flow operation condition of freeway gradually becomes the critical information for the freeway users and managers. In fact, electronic toll collection (ETC) transaction data effectively records operational information of vehicles on freeway, which provides a new method to estimate the travel speed of freeway. First, the paper analyzed the structure of ETC transaction data and presented the data preprocess procedure. Then, a dual-level travel speed calculation model was estab...

  11. Sensorless Speed Control of Traveling Wave Ultrasonic Motor

    OpenAIRE

    Flückiger, Markus; Bullo, Matteo; Perriard, Yves

    2006-01-01

    Ultrasonic motors are a good alternative to electromagnetic motors in medical robotics, since they are electromagnetically compatible. Estimating speed instead of using encoders reduces cost and dimension of the robot on the one hand and increases reliability on the other hand. However, no sensorless speed controller is yet industrialized. Analytical models of the traveling wave ultrasonic motor being too complex to be exploited for sensorless control purpose, we suggest speed estimation base...

  12. High-Speed Civil Transport Will Revolutionize Air Travel

    Science.gov (United States)

    1998-01-01

    NASA is developing advanced technologies that will allow industry to build a high-speed civil transport that will revolutionize overseas air travel. The technology challenges include developing low-cost materials and structural concepts as well as supersonic engines that can meet stringent noise and emissions standards. NASA's goal is to provide enabling technologies that will reduce the travel time to the Far East by 50 percent within 25 years, and do so at today's subsonic ticket prices. This research is part of NASA's Aeronautics and Space Transportation Technology (ASTT) Enterprise's strategy to sustain U.S. leadership in aeronautics and space. The Enterprise has set bold goals that are grouped into Three Pillars: Global Civil Aviation, Revolutionary Technology Leaps and Access to Space.

  13. Vocal correlates of individual sooty mangabey travel speed and direction.

    Science.gov (United States)

    Neumann, Christof; Zuberbühler, Klaus

    2016-01-01

    Many group-living animals coordinate movements with acoustic signals, but so far most studies have focused on how group movements are initiated. In this study, we investigated movement patterns of wild sooty mangabeys (Cercocebus atys), a mostly terrestrial, forest-dwelling primate. We provide quantitative results showing that vocalization rates of mangabey subgroups, but not of focal individuals, correlated with focal individuals' current movement patterns. More interestingly, vocal behaviour predicted whether individuals changed future speed, and possibly future travel direction. The role of vocalizations as a potential mechanism for the regulation of group movement was further highlighted by interaction effects that include subgroup size and the quality of poly-specific associations. Collectively, our results suggest that primate vocal behaviour can function beyond travel initiation in coordination and regulation of group movements. PMID:27547587

  14. Traveling waves and spreading speeds for time-space periodic monotone systems

    OpenAIRE

    Fang, Jian; Yu, Xiao; Zhao, Xiao-Qiang

    2015-01-01

    The theory of traveling waves and spreading speeds is developed for time-space periodic monotone semiflows with monostable structure. By using traveling waves of the associated Poincar\\'e maps in a strong sense, we establish the existence of time-space periodic traveling waves and spreading speeds. We then apply these abstract results to a two species competition reaction-advection-diffusion model. It turns out that the minimal wave speed exists and coincides with the single spreading speed f...

  15. Speed dependence of averaged EMG profiles in walking

    NARCIS (Netherlands)

    Hof, AL; Elzinga, H; Grimmius, W; Halbertsma, JPK

    2002-01-01

    Electromyogram (EMG) profiles strongly depend on walking speed and, in pathological gait, patients do not usually walk at normal speeds. EMG data was collected from 14 muscles in two groups of healthy young subjects who walked at five different speeds ranging from 0.75 to 1.75 ms(-1). We found that

  16. Planning the most suitable travel speed for high frequency railway lines

    DEFF Research Database (Denmark)

    Landex, Alex; Kaas, Anders H.

    2005-01-01

    This paper presents a new method to calculate the most suitable travel speed for high frequency railway lines to achieve as much capacity as possible for congested railway lines. The method calculates the most suitable travel speed based on the braking distance and information about the interlock......This paper presents a new method to calculate the most suitable travel speed for high frequency railway lines to achieve as much capacity as possible for congested railway lines. The method calculates the most suitable travel speed based on the braking distance and information about...

  17. Spreading speeds and traveling waves for non-cooperative reaction-diffusion systems

    CERN Document Server

    Wang, Haiyan

    2010-01-01

    Much has been studied on the spreading speed and traveling wave solutions for cooperative reaction-diffusion systems. In this paper, we shall establish the spreading speed for a large class of non-cooperative reaction-diffusion systems and characterize the spreading speed as the slowest speed of a family of non-constant traveling wave solutions. As an application, our results are applied to a partially cooperative system describing interactions between ungulates and grass.

  18. Calculating High Speed Centrifugal Compressor Performance from Averaged Measurements

    Science.gov (United States)

    Lou, Fangyuan; Fleming, Ryan; Key, Nicole L.

    2012-12-01

    To improve the understanding of high performance centrifugal compressors found in modern aircraft engines, the aerodynamics through these machines must be experimentally studied. To accurately capture the complex flow phenomena through these devices, research facilities that can accurately simulate these flows are necessary. One such facility has been recently developed, and it is used in this paper to explore the effects of averaging total pressure and total temperature measurements to calculate compressor performance. Different averaging techniques (including area averaging, mass averaging, and work averaging) have been applied to the data. Results show that there is a negligible difference in both the calculated total pressure ratio and efficiency for the different techniques employed. However, the uncertainty in the performance parameters calculated with the different averaging techniques is significantly different, with area averaging providing the least uncertainty.

  19. Averaged EMG profiles in jogging and running at different speeds

    NARCIS (Netherlands)

    Gazendam, Marnix G. J.; Hof, At L.

    2007-01-01

    EMGs were collected from 14 muscles with surface electrodes in 10 subjects walking 1.25-2.25 m s(-1) and running 1.25-4.5 m s(-1). The EMGs were rectified, interpolated in 100% of the stride, and averaged over all subjects to give an average profile. In running, these profiles could be decomposed in

  20. Traveling Faster than the Speed of Light in Non-Commutative Geometry

    OpenAIRE

    Hashimoto, Akikazu; Itzhaki, N.

    2000-01-01

    We study various dynamical aspects of solitons in non-commutative gauge theories and find surprising results. Among them is the observation that the solitons can travel faster than the speed of light for arbitrarily long distances.

  1. The volitional travel speed varies with reproductive state in mature female brown trout Salmo trutta

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Aarestrup, Kim; Dolby, Jes;

    2009-01-01

    This study tested the effect of reproduction on the volitional travel speed of mature female brown trout Salmo trutta L. The downstream travel speed in the pre-spawning state was 0·25 m s−1 (95% CI : 0·19, 0·34) while it increased significantly to 0·65 m s−1 (95% CI: 0·49, 0·87) in the post...

  2. Desing And Implementation Of A Digitally Controlled Compact Speed Driver For Travelling Wave Ultrasonic Motor

    Directory of Open Access Journals (Sweden)

    Altan Gencer

    2013-05-01

    Full Text Available In this paper, a compact size digitally controlled speed driver for travelling wave ultrasonic motor was designed and implemented. Although the driver system is light in weight, simple, small in size, it is possible to enter speed and direction digitally as well as tracking the real motor speed, voltage and current on an LCD. The implemented system was tested in a laboratory for different speed and load cases and obtained results are presented.

  3. TRAVELING WAVE SPEED AND SOLUTION IN REACTION-DIFFUSION EQUATION IN ONE DIMENSION

    Institute of Scientific and Technical Information of China (English)

    周天寿; 张锁春

    2001-01-01

    By Painlevé analysis, traveling wave speed and solution of reaction-diffusion equations for the concentration of one species in one spatial dimension are in detail investigated. When the exponent of the creation term is larger than the one of the annihilation term, two typical cases are studied, one with the exact traveling wave solutions, yielding the values of speeds, the other with the series expansion solution, also yielding the value of speed. Conversely, when the exponent of creation term is smaller than the one of the annihilation term, two typical cases are also studied, but only for one of them, there is a series development solution, yielding the value of speed, and for the other, traveling wave solution cannot exist. Besides, the formula of calculating speeds and solutions of planar wave within the thin boundary layer are given for a class of typical excitable media.

  4. Actuator disk model of wind farms based on the rotor average wind speed

    DEFF Research Database (Denmark)

    Han, Xing Xing; Xu, Chang; Liu, De You;

    2016-01-01

    Due to difficulty of estimating the reference wind speed for wake modeling in wind farm, this paper proposes a new method to calculate the momentum source based on the rotor average wind speed. The proposed model applies volume correction factor to reduce the influence of the mesh recognition...

  5. High-speed OTDM and WDM networks using traveling-wave electroabsorption modulators

    OpenAIRE

    Chou, H F; Bowers, J. E.

    2007-01-01

    We describe the design and performance of a number of elements based on traveling-wave electroabsorption modulators (TW-EAMs) in optical time-division-multiplexing (OTDM) and wavelength-division-multiplexing (WDM) networks. The incorporation of traveling-wave (TW) electrode design into electroabsorption modulators (EAMs) relieves the resistance-capacitance (RC) bandwidth limitation common to lumped components,. enabling higher operation speed without shortening the dev...

  6. High-Speed Train Stop-Schedule Optimization Based on Passenger Travel Convenience

    OpenAIRE

    Dingjun Chen; Shaoquan Ni; Chang’an Xu; Hongxia Lv; Simin Wang

    2016-01-01

    The stop-schedules for passenger trains are important to the operation planning of high-speed trains, and they decide the quality of passenger service and the transportation efficiency. This paper analyzes the specific manifestation of passenger travel convenience and proposes the concepts of interstation accessibility and degree of accessibility. In consideration of both the economic benefits of railway corporations and the travel convenience of passengers, a multitarget optimization model i...

  7. THE SPEED OF GRAVITY AND HYPER-FAST TRAVEL IN GENERAL RELATIVITY

    OpenAIRE

    Trunev A. P.

    2014-01-01

    The equation of parabolic type, describing the evolution of the gravitational field on the scale of the solar system, galaxy and cluster galaxies is derived from the Einstein equation. Space-time metric compatible with the post-Newtonian approximation and the metric of the expanding universe, and allowing hyper-fast travel in Einstein's theory of gravitation is considered. It is shown that the speed of hyper-fast travel depends on the implementation, including the parameters of ground state o...

  8. Time series models to simulate and forecast hourly averaged wind speeds in Quetta, Pakistan

    Energy Technology Data Exchange (ETDEWEB)

    Lalarukh Kamal [Balochistan University, Quetta (Pakistan). Dept. of Mathematics; Yasmin Zahra Jafri [Balochistan University, Quetta (Pakistan). Dept. of Statistics

    1997-07-01

    Stochastic simulation and forecast models of hourly average wind speeds are presented. Time series models take into account several basic features of wind speed data including autocorrelation, non-Gaussian distribution and diurnal nonstationarity. The positive correlation between consecutive wind speed observations is taken into account by fitting an ARMA (p,q) process to wind speed data transformed to make their distribution approximately Gaussian and standardized to remove scattering of transformed data. Diurnal variations have been taken into account to observe forecasts and its dependence on lead times. We find the ARMA (p,q) model suitable for prediction intervals and probability forecasts. (author)

  9. THE SPEED OF GRAVITY AND HYPER-FAST TRAVEL IN GENERAL RELATIVITY

    Directory of Open Access Journals (Sweden)

    Trunev A. P.

    2014-06-01

    Full Text Available The equation of parabolic type, describing the evolution of the gravitational field on the scale of the solar system, galaxy and cluster galaxies is derived from the Einstein equation. Space-time metric compatible with the post-Newtonian approximation and the metric of the expanding universe, and allowing hyper-fast travel in Einstein's theory of gravitation is considered. It is shown that the speed of hyper-fast travel depends on the implementation, including the parameters of ground state of the expanding universe. A criterion for the maximum speed of motion of material bodies has been proposed

  10. Neural Prediction of Wind Blowing Durations Based on Average Wind Speeds for Akhisar Location

    Directory of Open Access Journals (Sweden)

    Raşit Ata

    2014-05-01

    Full Text Available Renewable energy resources are widely preferred over conventional resources as they are environmentally favorable. Wind energy is one of the important renewable energy resources and has been widely developed recently. The energy produced from wind is dependent upon several factors. One of them is average wind speed and the other is wind blowing period. In this study, the wind blowing period is estimated based on annual average wind speed, Hellman coefficient and tower height using artificial neural networks (ANN. The results of ANN are compared with a conventional method in which Rayleigh distribution is employed.

  11. A novel car following model considering average speed of preceding vehicles group

    Science.gov (United States)

    Sun, Dihua; Kang, Yirong; Yang, Shuhong

    2015-10-01

    In this paper, a new car following model is presented by considering the average speed effect of preceding vehicles group in cyber-physical systems (CPS) environment. The effect of this new consideration upon the stability of traffic flow is examined through linear stability analysis. A modified Korteweg-de Vries (mKdV) equation was derived via nonlinear analysis to describe the propagating behavior of traffic density wave near the critical point. Good agreement between the simulation and the analytical results shows that average speed of preceding vehicles group leads to the stabilization of traffic systems, and thus can efficiently suppress the emergence of traffic jamming.

  12. High-Speed Train Stop-Schedule Optimization Based on Passenger Travel Convenience

    Directory of Open Access Journals (Sweden)

    Dingjun Chen

    2016-01-01

    Full Text Available The stop-schedules for passenger trains are important to the operation planning of high-speed trains, and they decide the quality of passenger service and the transportation efficiency. This paper analyzes the specific manifestation of passenger travel convenience and proposes the concepts of interstation accessibility and degree of accessibility. In consideration of both the economic benefits of railway corporations and the travel convenience of passengers, a multitarget optimization model is established. The model aims at minimizing stop cost and maximizing passenger travel convenience. Several constraints are applied to the model establishment, including the number of stops made by individual trains, the frequency of train service received by each station, the operation section, and the 0-1 variable. A hybrid genetic algorithm is designed to solve the model. Both the model and the algorithm are validated through case study.

  13. Surface area of early visual cortex predicts individual speed of traveling waves during binocular rivalry.

    Science.gov (United States)

    Genç, Erhan; Bergmann, Johanna; Singer, Wolf; Kohler, Axel

    2015-06-01

    Binocular rivalry ensues when different images are presented to the 2 eyes with conscious perception alternating between the possible interpretations. For large rivalry displays, perceptual transitions are initiated at one location and spread to other parts of the visual field, a phenomenon termed "traveling wave." Previous studies investigated the underlying neural mechanisms of the traveling wave and surmised that primary visual cortex might play an important role. We used magnetic resonance imaging and behavioral measures in humans to explore how interindividual differences in observers' subjective experience of the wave are related to anatomical characteristics of cortical regions. We measured wave speed in participants and confirmed the long-term stability of the individual values. Retinotopic mapping was employed to delineate borders of visual areas V1-V3 in order to determine surface area and cortical thickness in those regions. Only the surface areas of V1 and V2, but not V3 showed a correlation with wave speed. For individuals with larger V1/V2 area, the traveling wave needed longer to spread across the same distance in visual space. Our results highlight the role of early visual areas in mediating binocular rivalry and suggest possible mechanisms for the correlation between surface area and the traveling waves. PMID:24334918

  14. Ultrahigh-Speed Traveling-Wave Electroabsorption Modulator—Design and Analysis

    OpenAIRE

    Yu, Paul K.L.

    1999-01-01

    Theoretical analysis and numerical calculations are presented for ultrahigh-speed (>50 GHz) traveling-wave electroabsorption modulators (TW-EAM’s), including effects of velocity mismatch, impedance mismatch, and microwave attenuation. A quasi-static equivalent circuit model is used to examine the TW-EAM microwave properties, including the effect of photocurrent. Due to the optical propagation loss of the waveguide, the TW-EAM waveguide length for maximum RF link gain is currently limited to 2...

  15. Timescale Halo: Average-Speed Targets Elicit More Positive and Less Negative Attributions than Slow or Fast Targets

    OpenAIRE

    Ivan Hernandez; Jesse Lee Preston; Justin Hepler

    2014-01-01

    Research on the timescale bias has found that observers perceive more capacity for mind in targets moving at an average speed, relative to slow or fast moving targets. The present research revisited the timescale bias as a type of halo effect, where normal-speed people elicit positive evaluations and abnormal-speed (slow and fast) people elicit negative evaluations. In two studies, participants viewed videos of people walking at a slow, average, or fast speed. We find evidence for a timescale...

  16. Average electric wave spectra across the plasma sheet and their relation to ion bulk speed

    Science.gov (United States)

    Baumjohann, W.; Treumann, R. A.; Labelle, J.; Anderson, R. R.

    1989-01-01

    Using 4 months of tail data obtained by the ELF/MF spectrum analyzer of the wave experiment and the three-dimensional plasma instrument on board the AMPTE/IRM satellite, a statistical survey on the electric wave spectral density in the earth's plasma sheet has been conducted. More than 50,000 10-s-averaged electric wave spectra were analyzed with respect to differences between their values in the inner and outer central plasma sheet and the plasma sheet boundary layer as well as their dependence on radial distance and ion bulk speed. High-speed flows are dominated by broadband electrostatic noise with highest spectral densities in the plasma sheet boundary, where broadband electrostatic noise also exists during periods of low-speed flows. The broadband electrostatic noise has a typical spectral index of about -2. During low-speed flows the spectra in the central plasma sheet show distinct emissions at the electron cyclotron odd half-harmonic and upper hybrid frequency. Wave intensities during episodes of fast perpendicular flows are higher than those associated with fast parallel flows.

  17. Spreading Speed, Traveling Waves, and Minimal Domain Size in Impulsive Reaction–Diffusion Models

    KAUST Repository

    Lewis, Mark A.

    2012-08-15

    How growth, mortality, and dispersal in a species affect the species\\' spread and persistence constitutes a central problem in spatial ecology. We propose impulsive reaction-diffusion equation models for species with distinct reproductive and dispersal stages. These models can describe a seasonal birth pulse plus nonlinear mortality and dispersal throughout the year. Alternatively, they can describe seasonal harvesting, plus nonlinear birth and mortality as well as dispersal throughout the year. The population dynamics in the seasonal pulse is described by a discrete map that gives the density of the population at the end of a pulse as a possibly nonmonotone function of the density of the population at the beginning of the pulse. The dynamics in the dispersal stage is governed by a nonlinear reaction-diffusion equation in a bounded or unbounded domain. We develop a spatially explicit theoretical framework that links species vital rates (mortality or fecundity) and dispersal characteristics with species\\' spreading speeds, traveling wave speeds, as well as minimal domain size for species persistence. We provide an explicit formula for the spreading speed in terms of model parameters, and show that the spreading speed can be characterized as the slowest speed of a class of traveling wave solutions. We also give an explicit formula for the minimal domain size using model parameters. Our results show how the diffusion coefficient, and the combination of discrete- and continuous-time growth and mortality determine the spread and persistence dynamics of the population in a wide variety of ecological scenarios. Numerical simulations are presented to demonstrate the theoretical results. © 2012 Society for Mathematical Biology.

  18. Impact of On-street Parking on Urban Arterial Performance: A Quantitative Study on Travel Speed and Capacity Deterioration

    Directory of Open Access Journals (Sweden)

    Sugiarto

    2013-08-01

    Full Text Available Traffic congestion has been a serious social and technical problem since the early year’s rapid motorization in Banda Aceh, Aceh Province of Indonesia. Urban arterial performance becomes the crucial concerns of many traffic engineers. Arterial performances were analyzed using oblique cumulative plots and breakdown method. The approaches are time series treatment between cumulative vehicles arrival versus time contracted from data recorded by video cameras. Investigations were conducted during both morning and evening peak hours on three regular weekdays for observing saturation condition in order to observe the maximum capacity under prevailing conditions. This study examined the impact of presence on-street parking on deterioration both travel speed and capacity. It found that capacity diminished slightly 10-13% (275-368vph compared to the pre-breakdown condition. Likewise, during the breakdown, speed dropped about 13-19% (3-5kph controlled by pre-breakdown as well. The simulation software so called VISSIM 5.30 was governed to estimate the measurement of effectiveness (MOEs by removing on-street parking from a site of study. The MOEs reveal that removing on-street parking able to reduce average delay approximately 12 sec/veh (32% and increase speed about 5kph (24%.

  19. Further We Travel the Faster We Go.

    Science.gov (United States)

    Varga, Levente; Kovács, András; Tóth, Géza; Papp, István; Néda, Zoltán

    2016-01-01

    The average travelling speed increases in a nontrivial manner with the travel distance. This leads to scaling-like relations on quite extended spatial scales, for all mobility modes taken together and also for a given mobility mode in part. We offer a wide range of experimental results, investigating and quantifying this universal effect and its measurable causes. The increasing travelling speed with the travel distance arises from the combined effects of: choosing the most appropriate travelling mode; the structure of the travel networks; the travel times lost in the main hubs, starting or target cities; and the speed limit of roads and vehicles. PMID:26863605

  20. Experimental investigation of a moving averaging algorithm for motion perpendicular to the leaf travel direction in dynamic MLC target tracking

    International Nuclear Information System (INIS)

    Purpose: In dynamic multileaf collimator (MLC) motion tracking with complex intensity-modulated radiation therapy (IMRT) fields, target motion perpendicular to the MLC leaf travel direction can cause beam holds, which increase beam delivery time by up to a factor of 4. As a means to balance delivery efficiency and accuracy, a moving average algorithm was incorporated into a dynamic MLC motion tracking system (i.e., moving average tracking) to account for target motion perpendicular to the MLC leaf travel direction. The experimental investigation of the moving average algorithm compared with real-time tracking and no compensation beam delivery is described. Methods: The properties of the moving average algorithm were measured and compared with those of real-time tracking (dynamic MLC motion tracking accounting for both target motion parallel and perpendicular to the leaf travel direction) and no compensation beam delivery. The algorithm was investigated using a synthetic motion trace with a baseline drift and four patient-measured 3D tumor motion traces representing regular and irregular motions with varying baseline drifts. Each motion trace was reproduced by a moving platform. The delivery efficiency, geometric accuracy, and dosimetric accuracy were evaluated for conformal, step-and-shoot IMRT, and dynamic sliding window IMRT treatment plans using the synthetic and patient motion traces. The dosimetric accuracy was quantified via a γ-test with a 3%/3 mm criterion. Results: The delivery efficiency ranged from 89 to 100% for moving average tracking, 26%-100% for real-time tracking, and 100% (by definition) for no compensation. The root-mean-square geometric error ranged from 3.2 to 4.0 mm for moving average tracking, 0.7-1.1 mm for real-time tracking, and 3.7-7.2 mm for no compensation. The percentage of dosimetric points failing the γ-test ranged from 4 to 30% for moving average tracking, 0%-23% for real-time tracking, and 10%-47% for no compensation. Conclusions

  1. Verification of the helioseismology travel-time measurement technique and the inversion procedure for sound speed using artificial data

    International Nuclear Information System (INIS)

    We performed three-dimensional numerical simulations of the solar surface acoustic wave field for the quiet Sun and for three models with different localized sound-speed perturbations in the interior with deep, shallow, and two-layer structures. We used the simulated data generated by two solar acoustics codes that employ the same standard solar model as a background model, but utilize different integration techniques and different models of stochastic wave excitation. Acoustic travel times were measured using a time-distance helioseismology technique, and compared with predictions from ray theory frequently used for helioseismic travel-time inversions. It is found that the measured travel-time shifts agree well with the helioseismic theory for sound-speed perturbations, and for the measurement procedure with and without phase-speed filtering of the oscillation signals. This testing verifies the whole measuring-filtering-inversion procedure for static sound-speed anomalies with small amplitude inside the Sun outside regions of strong magnetic field. It is shown that the phase-speed filtering, frequently used to extract specific wave packets and improve the signal-to-noise ratio, does not introduce significant systematic errors. Results of the sound-speed inversion procedure show good agreement with the perturbation models in all cases. Due to its smoothing nature, the inversion procedure may overestimate sound-speed variations in regions with sharp gradients of the sound-speed profile.

  2. MODIFICATION OF CARBON STEEL BY LASER SURFACE MELTING: PART I: EFFECT OF LASER BEAM TRAVELLING SPEED ON MICROSTRUCTURAL FEATURES AND SURFACE HARDNESS

    Directory of Open Access Journals (Sweden)

    Hashem F. El-Labban

    2013-01-01

    Full Text Available The present study aims to improve the surface hardness of carbon steel by application of laser surface melting of effective conditions. The travelling speed of laser beam during this treatment is one of the important treatment conditions. This study aims to investigate the effect of laser surface melting with different beam speeds on macro and microstructure as well as the hardness distribution through the thickness of carbon steel. To achieve this target, three different travelling speeds (1500, 1000 and 500 mm min-1 at a constant beam power of 800 W were chosen in this study. The resulted laser treated specimens were investigated in macro and microscopically scale using optical and scanning electron microscope. Hardness measurements were also carried out through the thickness of the laser treated specimens. The laser treated areas with all used travelling speeds results in melted and solidified zone on the surface of the steel. In the same time, Plates of acicular martensite structure were observed within the upper part of the melted and solidified zone in almost all experimental conditions, while some bainite structure in ferrite grains are detected in its lower part. By increasing the travelling speed, the depth of the laser treated zone was decreases, while travelling speed has much less significant effect on the laser treated zone width. The size of the formed martensite plates was increased by decreasing the travelling speed from 1500 to 500 mm min-1. On the other hand, the travelling speed has a straight effect on the length of the acicular martensite; as the travelling speed increases, the acicular martensite became longer, while it shows fine acicular martensite at lower travelling speeds. The depth that full martensite structure can be reached is increased by increasing travelling speed. At lower travelling speed (500 mm min-1, large amount of bainite structure is observed at the center of the treated zone up to its lower end. The

  3. Tool geometry, rotation and travel speeds effects on the properties of dissimilar magnesium/aluminum friction stir welded lap joints

    International Nuclear Information System (INIS)

    Highlights: • Tool geometry, rotation and travel speeds show great effect on the microstructure stability of FSW joint. • Increasing rotation and travel speeds resulted in increasing the tensile strength and ductility of the joints. • Better intermixing between Al/Mg alloys was obtained by tapered threaded pin. • A mechanical interlocking mechanism proposed for higher ductility and superior tensile properties in FSW joints. - Abstract: Lap joint friction stir welding (FSW) between dissimilar AZ31B and Al 6061 alloys sheets was conducted using various welding parameters including tool geometry, rotation and travel speeds. Tapered threaded pin and tapered pin tools were applied to fabricate FSW joints, using different rotation and travel speeds. Metallurgical investigations including X-ray diffraction pattern (XRD), optical microscopy images (OM), scanning electron microscopy equipped with an energy-dispersive X-ray spectroscopy (SEM–EDS) and electron probe microanalysis (EPMA) were used to characterize joints microstructures made with different welding parameters. Intermetallic phases were detected in the weld zone (WZ). Various microstructures were observed in the stir zone which can be attributed to using different travel and rotation speeds. Mechanical evaluation including lap shear fracture load test and microhardness measurements indicated that by simultaneously increasing the tool rotation and travel speeds, the joint tensile strength and ductility reached a maximum value. Microhardness studies and extracted results from stress–strain curves indicated that mechanical properties were affected by FSW process. Furthermore, phase analyses by XRD indicated the presence of intermetallic compounds in the weld zone. Finally, in the Al/Mg dissimilar weld, fractography studies showed that intermetallic compounds formation in the weld zone had an influence on the failure mode

  4. Link-Based Signalized Arterial Progression Optimization with Practical Travel Speed

    Directory of Open Access Journals (Sweden)

    Wu Xianyu

    2013-01-01

    Full Text Available Bandwidth is defined as the maximum amount of green time for a designated movement as it passes through an arterial. In most previous studies, bandwidth has been referred to arterial bandwidth. In practice, a balance between link bandwidth and arterial bandwidth has proven to be important in optimizing coordinated signal timing plans, because not all drivers need to pass through all the intersections on an arterial. This study proposes an algorithm on how to obtain an optimal coordinated signal timing plan with both optimal link bandwidth and optimal arterial bandwidth considering practical vehicles’ speed. The weighted link bandwidth attainability is introduced as an additional measure of effectiveness for assessing the optimization results. The link bandwidth optimization is built based on the improvement of Messer’s algorithm about bandwidth optimization. The arterial bandwidth optimization algorithm takes into consideration the weighted link bandwidth attainability while selecting phase sequences. The proposed algorithm is demonstrated in a case study, and many improvements are archived when a balanced consideration is given to both link bandwidth and arterial bandwidth. Fine-tuning of initial signal timing plan is done using practical travel speed. The evaluation results show a rather significant improvement which is achieved.

  5. Whitham Averaged Equations and Modulational Stability of Periodic Traveling Waves of a Hyperbolic-Parabolic Balance Law

    CERN Document Server

    Barker, Blake; Noble, Pascal; Rodrigues, L Miguel; Zumbrun, Kevin

    2010-01-01

    In this note, we report on recent findings concerning the spectral and nonlinear stability of periodic traveling wave solutions of hyperbolic-parabolic systems of balance laws, as applied to the St. Venant equations of shallow water flow down an incline. We begin by introducing a natural set of spectral stability assumptions, motivated by considerations from the Whitham averaged equations, and outline the recent proof yielding nonlinear stability under these conditions. We then turn to an analytical and numerical investigation of the verification of these spectral stability assumptions. While spectral instability is shown analytically to hold in both the Hopf and homoclinic limits, our numerical studies indicates spectrally stable periodic solutions of intermediate period. A mechanism for this moderate-amplitude stabilization is proposed in terms of numerically observed ``metastability" of the the limiting homoclinic orbits.

  6. Influence of travel speed on spray deposition uniformity from an air-assisted variable-rate sprayer

    Science.gov (United States)

    A newly developed LiDAR-guided air-assisted variable-rate sprayer for nursery and orchard applications was tested at various travel speeds to compare its spray deposition and coverage uniformity with constant-rate applications. Spray samplers, including nylon screens and water-sensitive papers (WSP)...

  7. Effect of Travel Speed on the Stress Corrosion Behavior of Friction Stir Welded 2024-T4 Aluminum Alloy

    Science.gov (United States)

    Wang, Wen; Li, Tianqi; Wang, Kuaishe; Cai, Jun; Qiao, Ke

    2016-05-01

    The effect of travel speed on stress corrosion cracking (SCC) behavior of friction stir welded 2024-T4 aluminum alloy was investigated by slow strain rate tensile test. Microstructure and microhardness of the welded joint were studied. The results showed that the size of second phase particles increased with increasing travel speed, and the distribution of second phase particles was much more homogeneous at lower travel speed. The minimum microhardness was located at the boundary of nugget zone and thermomechanically affected zone. In addition, the SCC susceptibility of the friction stir welded joint increased with the increase of travel speed, owing to the size and distribution of second phase particles in the welds. The anodic applied potentials of -700, -650, -600 mV, and cathodic applied potential of -1200 mV facilitated SCC while the cathodic applied potential of -1000 mV improved the SCC resistance. The SCC behavior was mainly controlled by the metal anodic dissolution at the open circuit potential, and hydrogen accelerated metal embrittlement.

  8. Timescale halo: average-speed targets elicit more positive and less negative attributions than slow or fast targets.

    Science.gov (United States)

    Hernandez, Ivan; Preston, Jesse Lee; Hepler, Justin

    2014-01-01

    Research on the timescale bias has found that observers perceive more capacity for mind in targets moving at an average speed, relative to slow or fast moving targets. The present research revisited the timescale bias as a type of halo effect, where normal-speed people elicit positive evaluations and abnormal-speed (slow and fast) people elicit negative evaluations. In two studies, participants viewed videos of people walking at a slow, average, or fast speed. We find evidence for a timescale halo effect: people walking at an average-speed were attributed more positive mental traits, but fewer negative mental traits, relative to slow or fast moving people. These effects held across both cognitive and emotional dimensions of mind and were mediated by overall positive/negative ratings of the person. These results suggest that, rather than eliciting greater perceptions of general mind, the timescale bias may reflect a generalized positivity toward average speed people relative to slow or fast moving people. PMID:24421882

  9. Timescale halo: average-speed targets elicit more positive and less negative attributions than slow or fast targets.

    Directory of Open Access Journals (Sweden)

    Ivan Hernandez

    Full Text Available Research on the timescale bias has found that observers perceive more capacity for mind in targets moving at an average speed, relative to slow or fast moving targets. The present research revisited the timescale bias as a type of halo effect, where normal-speed people elicit positive evaluations and abnormal-speed (slow and fast people elicit negative evaluations. In two studies, participants viewed videos of people walking at a slow, average, or fast speed. We find evidence for a timescale halo effect: people walking at an average-speed were attributed more positive mental traits, but fewer negative mental traits, relative to slow or fast moving people. These effects held across both cognitive and emotional dimensions of mind and were mediated by overall positive/negative ratings of the person. These results suggest that, rather than eliciting greater perceptions of general mind, the timescale bias may reflect a generalized positivity toward average speed people relative to slow or fast moving people.

  10. Cellular telephone use during free-living walking significantly reduces average walking speed

    OpenAIRE

    Jacob E. Barkley; Lepp, Andrew

    2016-01-01

    Background Cellular telephone (cell phone) use decreases walking speed in controlled laboratory experiments and there is an inverse relationship between free-living walking speed and heart failure risk. The purpose of this study was to examine the impact of cell phone use on walking speed in a free-living environment. Methods Subjects (n = 1142) were randomly observed walking on a 50 m University campus walkway. The time it took each subject to walk 50 m was recorded and subjects were coded i...

  11. TRAVEL

    Institute of Scientific and Technical Information of China (English)

    Venice Lau

    2012-01-01

    <正>01"孤星之州"户外探险之旅>温润的气候、湛蓝的天空、充足的阳光和雄美壮丽的地貌资源,令美国得克萨斯州终年引人入胜,而旅游网站TravelTex正好带你畅游德州最刺激好玩的冒险之旅。德州拥有六百多英里波光粼粼的海岸线,毗邻墨西哥湾暖流,吸引着游客体验多姿多彩的户外活动,不论赏鸟、远足、游钓,还是斯库巴潜水,都是户外探险爱好者的理想胜地。狂热的垂钓迷可以沿着幽

  12. Verification of the Travel Time Measurement Technique and the Helioseismic Inversion Procedure for Sound Speed Using Artificial Data

    CERN Document Server

    Parchevsky, Konstantin V; Hartlep, Thomas; Kosovichev, Alexander G

    2012-01-01

    We performed 3D numerical simulations of the solar surface wave field for the quiet Sun and for three models with different localized sound-speed variations in the interior with: (i) deep, (ii) shallow, and (iii) two-layer structures. We used simulated data generated by two different codes which use the same standard solar model as a background model, but utilize two different integration techniques and use different models of stochastic wave excitation. Acoustic travel times were measured from all data sets using the time-distance helioseismology technique and compared with the ray theory predictions, frequently used for helioseismic travel-time inversions. It is found that the measured travel-time shifts agree well with the ray theory in both cases with and without phase-speed filtering for the shallow and deep perturbations. This testing verifies the whole measuring-filtering-inversion procedure for sound-speed anomalies inside the Sun. It is shown, that the phase-speed filtering, frequently used to improv...

  13. Planar undulator motion excited by a fixed traveling wave: Quasiperiodic Averaging, normal forms and the FEL Pendulum

    CERN Document Server

    Ellison, James A; Vogt, Mathias; Gooden, Matthew

    2013-01-01

    We present a mathematical analysis of planar motion of energetic electrons moving through a planar dipole undulator, excited by a fixed planar polarized plane wave Maxwell field in the X-Ray Free Electron Laser (FEL) regime. Our starting point is the 6D Lorentz system, which allows planar motions, and we examine this dynamical system as the wavelength of the traveling wave varies. By scalings and transformations the 6D system is reduced, without approximation, to a 2D system in a form for a rigorous asymptotic analysis using the Method of Averaging (MoA), a long time perturbation theory. The two dependent variables are a scaled energy deviation and a generalization of the so-called ponderomotive phase. As the wavelength varies the system passes through resonant and nonresonant (NR) zones and we develop NR and near-to-resonant (NtoR) normal form approximations. For a special initial condition and on resonance, the NtoR normal form reduces to the well-known FEL pendulum system. We then state and prove NR and Nt...

  14. MODIFICATION OF CARBON STEEL BY LASER SURFACE MELTING: PART I: EFFECT OF LASER BEAM TRAVELLING SPEED ON MICROSTRUCTURAL FEATURES AND SURFACE HARDNESS

    OpenAIRE

    Hashem F. El-Labban; Abdelaziz, M.; Essam R.I. Mahmoud

    2013-01-01

    The present study aims to improve the surface hardness of carbon steel by application of laser surface melting of effective conditions. The travelling speed of laser beam during this treatment is one of the important treatment conditions. This study aims to investigate the effect of laser surface melting with different beam speeds on macro and microstructure as well as the hardness distribution through the thickness of carbon steel. To achieve this target, three different travelling speeds (1...

  15. Application of Soft Squirrel-Cage Induction Motor Starting, Braking and Retarded Speed Operation for Crane Travel Mechanisms

    Directory of Open Access Journals (Sweden)

    B. I. Firago

    2010-01-01

    Full Text Available The paper considers an improvement of crane equipment operation, particularly, its travel mechanisms  at the expense of updating currently widely applied electric drives with squirrel-cage induction motors. The authors propose to use a pulse voltage regulator based on IGBT transistors with additional function of quasi-frequency control ability as a soft starter which has higher technical-economic indices in comparison with existing thyristor starters and prove its application by the results of their investigations. Application of such device in  electric drives of crane travel mechanisms where there is no need to carry out a technological speed regulation, allows to make soft starting, soft braking and accurate stoppage of an electric drive at the cost of  squirrel-cage induction motor transition to retarded speed prior to stoppage which is ensured by quasi-frequency motor control.

  16. Planar undulator motion excited by a fixed traveling wave. Quasiperiodic averaging normal forms and the FEL pendulum

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, James A.; Heinemann, Klaus [New Mexico Univ., Albuquerque, NM (United States). Dept. of Mathematics and Statistics; Vogt, Mathias [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Gooden, Matthew [North Carolina State Univ., Raleigh, NC (United States). Dept. of Physics

    2013-03-15

    We present a mathematical analysis of planar motion of energetic electrons moving through a planar dipole undulator, excited by a fixed planar polarized plane wave Maxwell field in the X-Ray FEL regime. Our starting point is the 6D Lorentz system, which allows planar motions, and we examine this dynamical system as the wave length {lambda} of the traveling wave varies. By scalings and transformations the 6D system is reduced, without approximation, to a 2D system in a form for a rigorous asymptotic analysis using the Method of Averaging (MoA), a long time perturbation theory. The two dependent variables are a scaled energy deviation and a generalization of the so- called ponderomotive phase. As {lambda} varies the system passes through resonant and nonresonant (NR) zones and we develop NR and near-to-resonant (NtoR) MoA normal form approximations. The NtoR normal forms contain a parameter which measures the distance from a resonance. For a special initial condition, for the planar motion and on resonance, the NtoR normal form reduces to the well known FEL pendulum system. We then state and prove NR and NtoR first-order averaging theorems which give explicit error bounds for the normal form approximations. We prove the theorems in great detail, giving the interested reader a tutorial on mathematically rigorous perturbation theory in a context where the proofs are easily understood. The proofs are novel in that they do not use a near identity transformation and they use a system of differential inequalities. The NR case is an example of quasiperiodic averaging where the small divisor problem enters in the simplest possible way. To our knowledge the planar prob- lem has not been analyzed with the generality we aspire to here nor has the standard FEL pendulum system been derived with associated error bounds as we do here. We briefly discuss the low gain theory in light of our NtoR normal form. Our mathematical treatment of the noncollective FEL beam dynamics problem in

  17. Rolling element bearing defect diagnosis under variable speed operation through angle synchronous averaging of wavelet de-noised estimate

    Science.gov (United States)

    Mishra, C.; Samantaray, A. K.; Chakraborty, G.

    2016-05-01

    Rolling element bearings are widely used in rotating machines and their faults can lead to excessive vibration levels and/or complete seizure of the machine. Under special operating conditions such as non-uniform or low speed shaft rotation, the available fault diagnosis methods cannot be applied for bearing fault diagnosis with full confidence. Fault symptoms in such operating conditions cannot be easily extracted through usual measurement and signal processing techniques. A typical example is a bearing in heavy rolling mill with variable load and disturbance from other sources. In extremely slow speed operation, variation in speed due to speed controller transients or external disturbances (e.g., varying load) can be relatively high. To account for speed variation, instantaneous angular position instead of time is used as the base variable of signals for signal processing purposes. Even with time synchronous averaging (TSA) and well-established methods like envelope order analysis, rolling element faults in rolling element bearings cannot be easily identified during such operating conditions. In this article we propose to use order tracking on the envelope of the wavelet de-noised estimate of the short-duration angle synchronous averaged signal to diagnose faults in rolling element bearing operating under the stated special conditions. The proposed four-stage sequential signal processing method eliminates uncorrelated content, avoids signal smearing and exposes only the fault frequencies and its harmonics in the spectrum. We use experimental data1

  18. The need for speed: testing acceleration for estimating animal travel rates in terrestrial dead-reckoning systems.

    Science.gov (United States)

    Bidder, Owen R; Soresina, Marion; Shepard, Emily L C; Halsey, Lewis G; Quintana, Flavio; Gómez-Laich, Agustina; Wilson, Rory P

    2012-02-01

    Numerous methods are currently available to track animal movements. However, only one of these, dead-reckoning, has the capacity to provide continuous data for animal movements over fine scales. Dead-reckoning has been applied almost exclusively in the study of marine species, in part due to the difficulty of accurately measuring the speed of terrestrial species. In the present study we evaluate the use of accelerometers and a metric known as overall dynamic body acceleration (ODBA) as a proxy for the measurement of speed for use in dead-reckoning. Data were collated from previous studies, for 10 species locomoting on a treadmill and their ODBA measured by an attached data logger. All species except one showed a highly significant linear relationship between speed and ODBA; however, there was appreciable inter- and intra-specific variance in this relationship. ODBA was then used to estimate speed in a simple trial run of a dead-reckoning track. Estimating distance travelled using speed derived from prior calibration for ODBA resulted in appreciable errors. We describe a method by which these errors can be minimised, by periodic ground-truthing (e.g., by GPS or VHF telemetry) of the dead-reckoned track and adjusting the relationship between speed and ODBA until actual known positions and dead-reckoned positions accord.

  19. The effect of travel speed and CTWD on the bead profile and microstructure of tandem GMA steel welds

    International Nuclear Information System (INIS)

    Automated tandem gas metal arc welding (T-GMAW) has been identified as a welding system potentially capable of increas¬ing productivity and minimising distortion in the fabrication of ship panels. The T-GMAW process was used in pulse-pulse mode on 6 mm plain carbon steel plate to determine the effect of welding travel speed (WTS) (1.0-2.0 m/min) and contact¬tip-to-workpiece distance (CTWD) (20-35 mm) on weld metal microstructure and bead profile. In this mode, the leading and trailing welding wires transfer metal alternately into a single molten weld pool at welding travel speeds much greater than those used in conventional single-wire gas metal arc welding (GMAW). The bead-on-plate (BOP) welding of 6 mm plain carbon steel plate resulted in adequate weld pool mixing and an acceptable level of micro structural homogeneity in the solidified weld metal for the welding conditions investigated. BOP welding tests were also undertaken on 20 mm plain carbon steel plate which results in a greater weld cooling rate compared with the thin 6 mm plate. In the 20 mm plate, a relatively homogenous weld metal microstructure was also present, but there was evidence of limited weld pool mixing. Also, in-situ analysis of the arcs during welding and post-test characterisation of the BOP samples showed that arc stability and bead profile are sensitive to both CTWD and WTS.

  20. Traveling waves and spreading speed on a lattice model with age structure

    Directory of Open Access Journals (Sweden)

    Zongyi Wang

    2012-09-01

    Full Text Available In this article, we study a lattice differential model for a single species with distributed age-structure in an infinite patchy environment. Using method of approaches by Diekmann and Thieme, we develop a comparison principle and construct a suitable sub-solution to the given model, and show that there exists a spreading speed of the system which in fact coincides with the minimal wave speed.

  1. Study on Network Remote Controlling Huge-Power Chopping Cascade Speed Regulation System Based on State-Space Averaging Model

    Directory of Open Access Journals (Sweden)

    Zhuo Zhang

    2014-07-01

    Full Text Available This paper deals with the modeling of DC-DC boost chopping circuit in a huge-power chopping cascade speed regulation system while the motor power level is over 1 megawatt. The model involves the Insulated Gate Bipolar Translator(IGBT & Free-Wheel Diode(FWD based on a state-space averaging method. It solves the problems of thedesigning of a control system in the chopping cascade speed regulation system when the controlling motor has a huge power. The system can be remote controlled through the industrial field network, and it has a good interface of human-computer interaction.The experiments show that the dual closed-loop control system is reliable and stable, it also has the better steady-state and dynamic characteristics and higher power factor compared with traditional cascade speed regulation systems. Based on this dual closed-loop control system, several devices with remarkable energy-saving effect have been running very well in the industrial sites. 

  2. Optics. Spatially structured photons that travel in free space slower than the speed of light.

    Science.gov (United States)

    Giovannini, Daniel; Romero, Jacquiline; Potoček, Václav; Ferenczi, Gergely; Speirits, Fiona; Barnett, Stephen M; Faccio, Daniele; Padgett, Miles J

    2015-02-20

    That the speed of light in free space is constant is a cornerstone of modern physics. However, light beams have finite transverse size, which leads to a modification of their wave vectors resulting in a change to their phase and group velocities. We study the group velocity of single photons by measuring a change in their arrival time that results from changing the beam's transverse spatial structure. Using time-correlated photon pairs, we show a reduction in the group velocity of photons in both a Bessel beam and photons in a focused Gaussian beam. In both cases, the delay is several micrometers over a propagation distance of ~1 meter. Our work highlights that, even in free space, the invariance of the speed of light only applies to plane waves.

  3. High Speed Travelling Wave Single-Photon Detectors With Near-Unity Quantum Efficiency

    CERN Document Server

    Pernice, W; Minaeva, O; Li, M; Goltsman, G N; Sergienko, A V; Tang, H X

    2011-01-01

    Ultrafast, high quantum efficiency single photon detectors are among the most sought-after elements in modern quantum optics and quantum communication. Close-to-unity photon detection efficiency is essential for scalable measurement-based quantum computation, quantum key distribution, and loophole-free Bell experiments. However, imperfect modal matching and finite photon absorption rates have usually limited the maximum attainable detection efficiency of single photon detectors. Here we demonstrate a superconducting nanowire detector atop nanophotonic waveguides and achieve single photon detection efficiency up to 94% at telecom wavelengths. Our detectors are fully embedded in a scalable, low loss silicon photonic circuit and provide ultrashort timing jitter of 18ps at multi-GHz detection rates. Exploiting this high temporal resolution we demonstrate ballistic photon transport in silicon ring resonators. The direct implementation of such a detector with high quantum efficiency, high detection speed and low ji...

  4. Travelling wave solutions to the K-P-P equation at supercritical wave speeds: a parallel to Simon Harris' probabilistic analysis

    OpenAIRE

    Kyprianou, A. E.

    2001-01-01

    Recently Harris using probabilistic methods alone has given new proofs for the known existence asymptotics and unique ness of travelling wave solutions to the KPP equation Following in this vein we outline alternative probabilistic proofs for wave speeds exceeding the critical minimal wave speed Speci cally the analysis is con ned to the study of additive and multiplicative martingales and the construction of size biased measures on the space of marked trees generated by the branching process...

  5. Numerical Simulation to Study the Effect of Arc Travelling Speed and Welding Sequences on Residual Stresses in Welded Sections of New Ferritic P92 Pipes

    Science.gov (United States)

    Wang, Xiaowei; Gong, Jianming; Zhao, Yanping; Wang, Yanfei; Ge, Zhiqiang

    2016-02-01

    New ferritic P92 steel is widely used in modern power plants due to its good combination of mechanical and physical properties. However, cracks are often formed in the welded sections during the fabrication or service. In order to ensure the structure integrity, the effects of residual stresses need to be considered. The objective of this paper is to investigate the influence of arc travelling speed and welding sequences on the residual stresses distribution in the welded sections of P92 pipes by finite element method (FEM). Results show that arc travelling speed and welding sequences have great effects on residual stresses distribution. With the arc travelling speed increasing, the residual stresses increase. Meanwhile, welding sequences of case B present smaller residual stresses and more symmetrical distribution of residual stresses at the weld centre line. Therefore, using slower arc travelling speed and case B welding sequences can be useful to decrease the residual stresses, which provides a reference for optimizing the welding technology and improving the fabrication process of new ferritic P92 welded pipes with small diameter and thick wall.

  6. Speed and income

    DEFF Research Database (Denmark)

    Fosgerau, Mogens

    2005-01-01

    The relationship between speed and income is established in a microeconomic model focusing on the trade-off between travel time and the risk of receiving a penalty for exceeding the speed limit. This is used to determine when a rational driver will choose to exceed the speed limit. The relationship...... between speed and income is found again in the empirical analysis of a cross-sectional dataset comprising 60,000 observations of car trips. This is used to perform regressions of speed on income, distance travelled, and a number of controls. The results are clearly statistically significant and indicate...... an average income elasticity of speed of 0.02; it is smaller at short distances and about twice as large at the longest distance investigated of 200 km....

  7. Weighted Average Distance Artificial Fish Swarm Algorithm for Solving Traveling Salesman Problems%一种求解 TSP 的加权平均距离人工鱼群算法

    Institute of Scientific and Technical Information of China (English)

    袁梦茹; 黄宜庆; 李小凤

    2016-01-01

    Based on the traditional artificial fish swarm algorithm(AFSA),a weighted average distance ar-tificial fish swarm algorithm (WAD-AFSA) was proposed.Foraging behavior vision of the artificial fish was improved and a strategy of weighted average distance vision was introduced in WAD-AFSA.So,the convergence speed of the presented algorithm was improved.Numerical simulation results showed that compared with the traditional artificial fish swarm algorithm,the proposed WAD-AFSA converges faster and also has better optimization preference in the optimization for standard function and traveling salesman problem(TSP) .%在传统人工鱼群算法的基础上,提出了一种加权平均距离人工鱼群算法(WAD-AFSA)。该算法对人工鱼群觅食行为的视野进行改进,引入一种加权平均距离策略,有效地提高了算法的收敛速度。数值仿真结果表明,与传统的人工鱼群算法相比,WAD-AFSA 在标准函数测试和旅行商问题(TSP)中的优化效果更好,收敛速度更快。

  8. Emporiatrics: The Travellers Medicine

    OpenAIRE

    Sushma, R; Nagabhushana, D

    2012-01-01

    Travel broadens the mind" and people have been extolling the merits of travel for a very long time .The general belief is that travel is good for travelers mentally and physically. But while travel can indeed be interesting and exciting, and good for mental and physical wellbeing, all too often it can be harmful to a traveler's health (1) .The increase in numbers of travellers and the speed at which they travel has not only had economic, cultural, and social repercussions, but medical, e...

  9. Influence of engine speed and the course of the fuel injection characteristics on forming the average combustion temperature in the cylinder of turbo diesel engine

    Directory of Open Access Journals (Sweden)

    Piotr GUSTOF

    2007-01-01

    Full Text Available Average combustion temperatures inside a turbo diesel engine for the same load and the same total doze of fuel for two rotational speeds: 2004 [rpm] and 4250 [rpm] are presented in this paper. The aim of this work is also the evaluation of the influence of the temporary course of the fuel injection characteristics on forming temperature in theengine cylinder space for these temperatures. The calculations were carried out by means of two zone combustion model.

  10. High speed laser drilling of metals using a high repetition rate, high average power ultrafast fiber CPA system.

    Science.gov (United States)

    Ancona, A; Röser, F; Rademaker, K; Limpert, J; Nolte, S; Tünnermann, A

    2008-06-01

    We present an experimental study on the drilling of metal targets with ultrashort laser pulses at high repetition rates (from 50 kHz up to 975 kHz) and high average powers (up to 68 Watts), using an ytterbium-doped fiber CPA system. The number of pulses to drill through steel and copper sheets with thicknesses up to 1 mm have been measured as a function of the repetition rate and the pulse energy. Two distinctive effects, influencing the drilling efficiency at high repetition rates, have been experimentally found and studied: particle shielding and heat accumulation. While the shielding of subsequent pulses due to the ejected particles leads to a reduced ablation efficiency, this effect is counteracted by heat accumulation. The experimental data are in good qualitative agreement with simulations of the heat accumulation effect and previous studies on the particle emission. However, for materials with a high thermal conductivity as copper, both effects are negligible for the investigated processing parameters. Therefore, the full power of the fiber CPA system can be exploited, which allows to trepan high-quality holes in 0.5mm-thick copper samples with breakthrough times as low as 75 ms. PMID:18545607

  11. Modified Motor Vehicles Travel Speed Models on the Basis of Curb Parking Setting under Mixed Traffic Flow

    Directory of Open Access Journals (Sweden)

    Zhenyu Mei

    2012-01-01

    Full Text Available The ongoing controversy about in what condition should we set the curb parking has few definitive answers because comprehensive research in this area has been lacking. Our goal is to present a set of heuristic urban street speed functions under mixed traffic flow by taking into account impacts of curb parking. Two impacts have been defined to classify and quantify the phenomena of motor vehicles' speed dynamics in terms of curb parking. The first impact is called Space impact, which is caused by the curb parking types. The other one is the Time impact, which results from the driver maneuvering in or out of parking space. In this paper, based on the empirical data collected from six typical urban streets in Nanjing, China, two models have been proposed to describe these phenomena for one-way traffic and two-way traffic, respectively. An intensive experiment has been conducted in order to calibrate and validate these proposed models, by taking into account the complexity of the model parameters. We also provide guidelines in terms of how to cluster and calculate those models' parameters. Results from these models demonstrated promising performance of modeling motor vehicles' speed for mixed traffic flow under the influence of curb parking.

  12. Maglev vehicles and superconductor technology: Integration of high-speed ground transportation into the air travel system

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, L.R.; Rote, D.M.; Hull, J.R.; Coffey, H.T.; Daley, J.G.; Giese, R.F.

    1989-04-01

    This study was undertaken to (1) evaluate the potential contribution of high-temperature superconductors (HTSCs) to the technical and economic feasibility of magnetically levitated (maglev) vehicles, (2) determine the status of maglev transportation research in the United States and abroad, (3) identify the likelihood of a significant transportation market for high-speed maglev vehicles, and (4) provide a preliminary assessment of the potential energy and economic benefits of maglev systems. HTSCs should be considered as an enhancing, rather than an enabling, development for maglev transportation because they should improve reliability and reduce energy and maintenance costs. Superconducting maglev transportation technologies were developed in the United States in the late 1960s and early 1970s. Federal support was withdrawn in 1975, but major maglev transportation programs were continued in Japan and West Germany, where full-scale prototypes now carry passengers at speeds of 250 mi/h in demonstration runs. Maglev systems are generally viewed as very-high-speed train systems, but this study shows that the potential market for maglev technology as a train system, e.g., from one downtown to another, is limited. Rather, aircraft and maglev vehicles should be seen as complementing rather than competing transportation systems. If maglev systems were integrated into major hub airport operations, they could become economical in many relatively high-density US corridors. Air traffic congestion and associated noise and pollutant emissions around airports would also be reduced. 68 refs., 26 figs., 16 tabs.

  13. Fabrication and characterization of novel high-speed InGaAs/InP uni-traveling-carrier photodetector for high responsivity

    Institute of Scientific and Technical Information of China (English)

    陈庆涛; 任晓敏; 黄永清; 费嘉瑞; 段晓峰; 刘凯; 刘锋; 康超; 汪君楚; 房文敬

    2015-01-01

    A top-illuminated circular mesa uni-traveling-carrier photodetector (UTC-PD) is proposed in this paper. By employ-ing Gaussian graded doping in InGaAs absorption layer and InP depleted layer, the responsivity and high speed response characteristics of the device are optimized simultaneously. The responsivity up to 1.071 A/W (the external quantum effi-ciency of 86%) is obtained at 1550 nm with a 40-µm diameter device under 10-V reverse bias condition. Meanwhile, the dark current of 7.874 nA and the 3-dB bandwidth of 11 GHz are obtained with the same device at a reverse bias voltage of 3V.

  14. On the dynamics of traveling phase-oscillators with positive and negative couplings

    International Nuclear Information System (INIS)

    We investigate numerically the dynamics of traveling clusters in systems of phase oscillators, some of which possess positive couplings and others negative couplings. The phase distribution, speed of traveling, and average separation between clusters, as well as the order parameters for positive and negative oscillators, are computed as the ratio of the two coupling constants and the fraction of positive oscillators are varied. The dependence of the traveling speed on these parameters is obtained and is observed to fit well with the numerical data of the systems. With the help of this, we describe the conditions for the traveling state to appear in the systems with and without a periodic driving field.

  15. Travelers' Health: Pregnant Travelers

    Science.gov (United States)

    ... itinerary if not accustomed to planned activities Postpone travel if risks outweigh benefits Box 8-02. Contraindications for travel during pregnancy Absolute Contraindications Abruptio placentae Active labor ...

  16. Emporiatrics: The Travellers Medicine

    Directory of Open Access Journals (Sweden)

    R Sushma

    2012-04-01

    Full Text Available Travel broadens the mind" and people have been extolling the merits of travel for a very long time .The general belief is that travel is good for travelers mentally and physically. But while travel can indeed be interesting and exciting, and good for mental and physical wellbeing, all too often it can be harmful to a traveler's health (1 .The increase in numbers of travellers and the speed at which they travel has not only had economic, cultural, and social repercussions, but medical, epidemiological, and medico-legal consequences as well. Travel medicine or Emporiatrics is the branch of medicine that deals with the prevention and management of health problems of international travelers (2. The art of travel medicine is selecting the necessary prevention strategy without unnecessary adverse events, cost or inconvenience" (3. Travel health advice is primarily aimed at prevention, and is therefore offered before travel. It includes steps taken before travel like Medical examinations and screening, Psychological preparation, Provision of a medical kit, First aid training, Preventive measures for prevention of thermal injury, Insure and plan for aeromedical evacuation and repatriation, Advice regarding accidents and related hazards, Special provisions for specific travel hazards and Protection against tropical diseases. There is also an aspect of travel health which is provided after return from travel, which is usually diagnostic (4,5. Giving adequate advice on travel health requires a good knowledge about local health hazards overseas, public health measures, and the effectiveness of immunization and prophylaxis. In summary, travel medicine will be established as an interdisciplinary special discipline in the next years and will be characterized by new risks and on the other hand by new methods of therapy and prophylaxis.

  17. 浅析武广“高铁旅游生态圈”的构建策略及保障机制%Analysis on the Building Strategies and Protection Mechanisms of Wuhan- Guangzhou "High- speed Rail Travel Ecosystem"

    Institute of Scientific and Technical Information of China (English)

    方微

    2012-01-01

    中国高铁的快速发展催生出新时代高铁旅游的发展,关于通过构建高铁旅游生态圈来推动高铁沿线城市旅游发展的讨论和研究开始进入视野。本文以武广高铁为载体,建立联动广东、湖南、湖北旅游的高铁旅游生态圈,从树立“粤湘鄂”旅游品牌、交通服务体系、旅游服务系统、加强旅游产品创新等方面探讨了构建武广高铁旅游生态圈的策略,并提出相应的保障机制,激发粤、湘、鄂旅游在高铁时代发展的新活力。%The rapid development of Chinab high - speed rail spawned the development of high - speed rail travel of a new era, discussions and researches on high - speed railway line to promote urban tourism development by building high - speed rail travel ecosystem began to enter people's field of vision. With Wuhan - Guangzhou high - speed rail as a carrier, this article builds the high speed rail travel ecosystem among the linkage of Guangdong, Hunan and Hubei, and discusses the strategy of building eco - tourism circle of Wuhan - Guangzhou high - speed rail from establishing tourism brand of " Guangdong, Hunan, Hubei" , traffic service system, tourism service sys- tem, and strengthening the tourism product innovation and so on. Finally, the article puts forward corresponding security mechanisms to stimulate new vitality of Guangdong, Hunan and Hubei tourism development high - speed rail in the era.

  18. Speeding Up

    Institute of Scientific and Technical Information of China (English)

    YU SHUJUN

    2010-01-01

    In the wake of the global financial crisis, China has amazed the world with the speed of its economic recovery. But what has been even more surprising is the speed of its railway evolution. The unveiling of the 1,069-km Wuhan-Guangzhou High-speed Railway on December 26, 2009 pushed China's high-speed rail sys-tem-the total mileage, the average speed and the technology-to rank first in the world almost overnight.

  19. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Alex

    2015-11-01

    The Connected Traveler project is a multi-disciplinary undertaking that seeks to validate potential for transformative transportation system energy savings by incentivizing efficient traveler behavior. This poster outlines various aspects of the Connected Traveler project, including market opportunity, understanding traveler behavior and decision-making, automation and connectivity, and a projected timeline for Connected Traveler's key milestones.

  20. Averaged Propulsive Body Acceleration (APBA) Can Be Calculated from Biologging Tags That Incorporate Gyroscopes and Accelerometers to Estimate Swimming Speed, Hydrodynamic Drag and Energy Expenditure for Steller Sea Lions.

    Science.gov (United States)

    Ware, Colin; Trites, Andrew W; Rosen, David A S; Potvin, Jean

    2016-01-01

    Forces due to propulsion should approximate forces due to hydrodynamic drag for animals horizontally swimming at a constant speed with negligible buoyancy forces. Propulsive forces should also correlate with energy expenditures associated with locomotion-an important cost of foraging. As such, biologging tags containing accelerometers are being used to generate proxies for animal energy expenditures despite being unable to distinguish rotational movements from linear movements. However, recent miniaturizations of gyroscopes offer the possibility of resolving this shortcoming and obtaining better estimates of body accelerations of swimming animals. We derived accelerations using gyroscope data for swimming Steller sea lions (Eumetopias jubatus), and determined how well the measured accelerations correlated with actual swimming speeds and with theoretical drag. We also compared dive averaged dynamic body acceleration estimates that incorporate gyroscope data, with the widely used Overall Dynamic Body Acceleration (ODBA) metric, which does not use gyroscope data. Four Steller sea lions equipped with biologging tags were trained to swim alongside a boat cruising at steady speeds in the range of 4 to 10 kph. At each speed, and for each dive, we computed a measure called Gyro-Informed Dynamic Acceleration (GIDA) using a method incorporating gyroscope data with accelerometer data. We derived a new metric-Averaged Propulsive Body Acceleration (APBA), which is the average gain in speed per flipper stroke divided by mean stroke cycle duration. Our results show that the gyro-based measure (APBA) is a better predictor of speed than ODBA. We also found that APBA can estimate average thrust production during a single stroke-glide cycle, and can be used to estimate energy expended during swimming. The gyroscope-derived methods we describe should be generally applicable in swimming animals where propulsive accelerations can be clearly identified in the signal-and they should also

  1. Virtual speed sensors based algorithm for expressway traffic state estimation

    Institute of Scientific and Technical Information of China (English)

    XU DongWei; DONG HongHui; JIA LiMin; QIN Yong

    2012-01-01

    The accurate estimation of expressway traffic state can provide decision-making for both travelers and traffic managers.The speed is one of the most representative parameter of the traffic state.So the expressway speed spatial distribution can be taken as the expressway traffic state equivalent.In this paper,an algorithm based on virtual speed sensors (VSS) is presented to estimate the expressway traffic state (the speed spatial distribution).To gain the spatial distribution of expressway traffic state,virtual speed sensors are defined between adjacent traffic flow sensors.Then,the speed data extracted from traffic flow sensors in time series are mapped to space series to design virtual speed sensors.Then the speed of virtual speed sensors can be calculated with the weight matrix which is related with the speed of virtual speed sensors and the speed data extracted from traffic flow sensors and the speed data extracted from traffic flow sensors in time series.Finally,the expressway traffic state (the speed spatial distribution) can be gained.The acquisition of average travel speed of the expressway is taken for application of this traffic state estimation algorithm.One typical expressway in Beijing is adopted for the experiment analysis.The results prove that this traffic state estimation approach based on VSS is feasible and can achieve a high accuracy.

  2. Traveling Wave Speed and Solution in Reaction- Diffusion Equation in One Dimension%一维反应扩散方程中的行波波速及行波解

    Institute of Scientific and Technical Information of China (English)

    周天寿; 张锁春

    2001-01-01

    By Painlevé analysis, traveling wave s p eed and solution of reaction-diffusion equations for the concentration of one sp ecies in one spatial dimension are in detail investigated. When the exponent of the creation term is larger than the one of the annihilation term, two typical c ases are studied, one with the exact traveling wave solutions, yielding the valu es of speeds, the other with the series expansion solution, also yielding the va l ue of speed. Conversely, when the exponent of creation term is smaller than the one of the annihilation term, two typical cases are also studied, but only for o ne of them, there is a series development solution, yielding the value of speed, and for the other, traveling wave solution cannot exist. Besides, the formula o f calculating speeds and solutions of planar wave within the thin boundary layer are given for a class of typical excitable media.%通过Painlevé分析,详细研究了一类一维化学反应扩散方程中的行波解及波速.分别给出了当歼灭项的指数大于创造项的指数及创造项的指数大于歼灭项的指数时,这两种情形下的波速及行波解的显式表示.此外,还给出了一类常见激励介质中的波速及平面波解在薄的边界层内的公式.

  3. Travelers' Health: Travel and Breastfeeding

    Science.gov (United States)

    ... hand expression, see www.workandpump.com/handexpression.htm ). TRAVELING WITH A BREASTFEEDING CHILD Breastfeeding provides unique benefits to mothers and children traveling together. Health care ...

  4. Validation of travel times to hospital estimated by GIS

    Directory of Open Access Journals (Sweden)

    Sauerzapf Violet

    2006-09-01

    Full Text Available Abstract Background An increasing number of studies use GIS estimates of car travel times to health services, without presenting any evidence that the estimates are representative of real travel times. This investigation compared GIS estimates of travel times with the actual times reported by a sample of 475 cancer patients who had travelled by car to attend clinics at eight hospitals in the North of England. Methods Car travel times were estimated by GIS using the shortest road route between home address and hospital and average speed assumptions. These estimates were compared with reported journey times and straight line distances using graphical, correlation and regression techniques. Results There was a moderately strong association between reported times and estimated travel times (r = 0.856. Reported travel times were similarly related to straight line distances. Altogether, 50% of travel time estimates were within five minutes of the time reported by respondents, 77% were within ten minutes and 90% were within fifteen minutes. The distribution of over- and under-estimates was symmetrical, but estimated times tended to be longer than reported times with increasing distance from hospital. Almost all respondents rounded their travel time to the nearest five or ten minutes. The reason for many cases of reported journey times exceeding the estimated times was confirmed by respondents' comments as traffic congestion. Conclusion GIS estimates of car travel times were moderately close approximations to reported times. GIS travel time estimates may be superior to reported travel times for modelling purposes because reported times contain errors and can reflect unusual circumstances. Comparison with reported times did not suggest that estimated times were a more sensitive measure than straight line distance.

  5. Travel Guide (Travelling Fires)

    OpenAIRE

    Stern-Gottfried, Jamie; Rein, Guillermo; Torero, Jose L

    2009-01-01

    Close inspection of real fires in large, open compartments reveals that they do not burn simultaneously throughout the whole compartment. Instead, these fires tend to move as flames spread, partitions or false ceilings break, and ventilation changes through glazing failure. These fires have been labelled ‘travelling fires’ and represent a new understanding of fire behaviour in modern building layouts. Despite these observations, fire scenarios currently used for the structural fire design of ...

  6. Travel medicine

    Science.gov (United States)

    Aw, Brian; Boraston, Suni; Botten, David; Cherniwchan, Darin; Fazal, Hyder; Kelton, Timothy; Libman, Michael; Saldanha, Colin; Scappatura, Philip; Stowe, Brian

    2014-01-01

    Abstract Objective To define the practice of travel medicine, provide the basics of a comprehensive pretravel consultation for international travelers, and assist in identifying patients who might require referral to travel medicine professionals. Sources of information Guidelines and recommendations on travel medicine and travel-related illnesses by national and international travel health authorities were reviewed. MEDLINE and EMBASE searches for related literature were also performed. Main message Travel medicine is a highly dynamic specialty that focuses on pretravel preventive care. A comprehensive risk assessment for each individual traveler is essential in order to accurately evaluate traveler-, itinerary-, and destination-specific risks, and to advise on the most appropriate risk management interventions to promote health and prevent adverse health outcomes during travel. Vaccinations might also be required and should be personalized according to the individual traveler’s immunization history, travel itinerary, and the amount of time available before departure. Conclusion A traveler’s health and safety depends on a practitioner’s level of expertise in providing pretravel counseling and vaccinations, if required. Those who advise travelers are encouraged to be aware of the extent of this responsibility and to refer all high-risk travelers to travel medicine professionals whenever possible. PMID:25500599

  7. State Averages

    Data.gov (United States)

    U.S. Department of Health & Human Services — A list of a variety of averages for each state or territory as well as the national average, including each quality measure, staffing, fine amount and number of...

  8. Connected Traveler

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-01

    The Connected Traveler framework seeks to boost the energy efficiency of personal travel and the overall transportation system by maximizing the accuracy of predicted traveler behavior in response to real-time feedback and incentives. It is anticipated that this approach will establish a feedback loop that 'learns' traveler preferences and customizes incentives to meet or exceed energy efficiency targets by empowering individual travelers with information needed to make energy-efficient choices and reducing the complexity required to validate transportation system energy savings. This handout provides an overview of NREL's Connected Traveler project, including graphics, milestones, and contact information.

  9. Travel and the emergence of infectious diseases.

    OpenAIRE

    Wilson, M.E.

    1995-01-01

    Travel is a potent force in the emergence of disease. Migration of humans has been the pathway for disseminating infectious diseases throughout recorded history and will continue to shape the emergence, frequency, and spread of infections in geographic areas and populations. The current volume, speed, and reach of travel are unprecedented. The consequences of travel extend beyond the traveler to the population visited and the ecosystem. When they travel, humans carry their genetic makeup, imm...

  10. Travel sketches

    OpenAIRE

    Kolakowski, Marcin

    2013-01-01

    Collection of quick travel sketches from private sketchbooks (mixed techniques, pencil, ink pens, water colour, pastels). Contributions to University Gallery showing travel sketches of alumni of Leibniz Universität Hannover - Landscape Architecture Faculty

  11. Travel Tips

    Science.gov (United States)

    ... taking a quick trip with your family or studying abroad for several months, it's easier to get sick ... Keeping Your Cool in the Cold and Snow Studying Abroad Traveling and Asthma Food Allergies and Travel Food ...

  12. 武广高速铁路旅客出行特征和集散特性调查与分析%Survey and Analysis on Passenger Travel Characteristics and Distribution Features of Wuhan-Guangzhou High Speed Railway

    Institute of Scientific and Technical Information of China (English)

    李建斌

    2011-01-01

    High speed railway is in developing stage in China at present, the firsthand information of operation field is lacking. This paper summarizes and analyzes the passenger travel characteristics, including age structure, occupation distribution, income features, travel cost sources, purposes and choice intentions of travels, and distribution characteristics of passenger flows along the line, including time of collection and distribution of passengers arriving and waiting at the stations, peak hour factors and collection and distribution features, by means of the sampling survey on passengers in Wuhan-Guangzhou high speed railway stations. Based on the research results of relative projects, the peak hour factors obtained by survey in stations along the railway line are verified.%目前我国高速铁路正处于发展期,运营现场的第一手资料还比较缺乏.通过对武广高速铁路沿线车站旅客的抽样调查,归纳和分析了旅客的出行特征,包括年龄结构、职业分布、收入特征、旅费来源、出行目的和选择意向等;以及沿线旅客的集散特性,包括旅客到达车站和候车的时间分布及高峰小时系数和集散方式等.并结合有关课题的研究成果,对沿线车站调查的高峰小时系数进行了验证.

  13. Travelers' Health: Cruise Ship Travel

    Science.gov (United States)

    ... Counterfeit Drugs Cruise Ship Travel Families with Children Fish Poisoning in Travelers Food and Water Getting Health ... INJURY ABOARD CRUISE SHIPS Cruise ship medical clinics deal with a wide variety of illnesses and injuries. ...

  14. Quaternion Averaging

    Science.gov (United States)

    Markley, F. Landis; Cheng, Yang; Crassidis, John L.; Oshman, Yaakov

    2007-01-01

    Many applications require an algorithm that averages quaternions in an optimal manner. For example, when combining the quaternion outputs of multiple star trackers having this output capability, it is desirable to properly average the quaternions without recomputing the attitude from the the raw star tracker data. Other applications requiring some sort of optimal quaternion averaging include particle filtering and multiple-model adaptive estimation, where weighted quaternions are used to determine the quaternion estimate. For spacecraft attitude estimation applications, derives an optimal averaging scheme to compute the average of a set of weighted attitude matrices using the singular value decomposition method. Focusing on a 4-dimensional quaternion Gaussian distribution on the unit hypersphere, provides an approach to computing the average quaternion by minimizing a quaternion cost function that is equivalent to the attitude matrix cost function Motivated by and extending its results, this Note derives an algorithm that deterniines an optimal average quaternion from a set of scalar- or matrix-weighted quaternions. Rirthermore, a sufficient condition for the uniqueness of the average quaternion, and the equivalence of the mininiization problem, stated herein, to maximum likelihood estimation, are shown.

  15. Study of speed endurance middle distance runners

    Directory of Open Access Journals (Sweden)

    Golovaschenko R.V.

    2013-12-01

    Full Text Available Purpose : To investigate the boost performance speed endurance runners who specialize in middle-distance running . Material and methods : The study involved team members Vinnytsia region in an amount of 44 people, whose average age was 20,2 ± 2,1 years. Classes are held during the 21-day mesocycle, 5 times a week, twice a day. Things were aimed at enhancing the development of indicators of special speed endurance. Results : The dynamics of the running speed of the model segments that characterize speed endurance athletes. Proved that the improved running 400 meter intervals helps reduce travel time competitive distance of 1500 meters. Conclusion : The use of the program contributes to higher speed endurance, which determines the result in the women's 1,500 meters.

  16. Towards a Metropolitan Fundamental Diagram Using Travel Survey Data.

    Science.gov (United States)

    Wang, Kai; Levinson, David M

    2016-01-01

    Using travel diary data from 2000-2001 and 2010-2012 this research examines fundamental traffic relationships at the metropolitan level. The results of this paper can help to explain the causes of some traffic phenomena. Network average speed by time of day can be explained by trip length and cumulative number of vehicles on the road. A clockwise hysteresis loop is found in the Metropolitan Fundamental Diagram in the morning period and a reverse process happens in the afternoon.

  17. Towards a Metropolitan Fundamental Diagram Using Travel Survey Data.

    Science.gov (United States)

    Wang, Kai; Levinson, David M

    2016-01-01

    Using travel diary data from 2000-2001 and 2010-2012 this research examines fundamental traffic relationships at the metropolitan level. The results of this paper can help to explain the causes of some traffic phenomena. Network average speed by time of day can be explained by trip length and cumulative number of vehicles on the road. A clockwise hysteresis loop is found in the Metropolitan Fundamental Diagram in the morning period and a reverse process happens in the afternoon. PMID:26866913

  18. Danish long distance travel A study of Danish travel behaviour and the role of infrequent travel activities

    OpenAIRE

    Knudsen, Mette Aagaard; Rich, Jeppe; Nielsen, Otto Anker

    2014-01-01

    Historically there has been a lack of knowledge with respect to long distance travel. Due to the considerable contribution of long distance travel to total travelled kilometres and the related energy consumption from the transport sector and derived impacts on greenhouse emissions, this is problematic. The average travel distance has steadily increased during the latest decades together with the increasing motorisation of daily travel and international aviation. Previously most focus has been...

  19. Long distance travel ‘today’

    DEFF Research Database (Denmark)

    Christensen, Linda

    2014-01-01

    per year og which a third is for international destinations, a third is for domestic second homes and a third are other domestic trips. However, 87% of the kilometres are for international destinations and only 4% are for domestic second homes. Travel activity is very uneven distributed with only half...... of the population having had a journey during the last three month. At the other hand 60% have travelled internationally during the last year and only 2% have never travelled abroad. The paper presents among other things how the travel activity is distributed on travel purpose and mode and how the......This paper presents an overview of the Dane’s long distance travel. It is a part of the Drivers and Limits project about long distance travel. Long distance travel is in the project defined as infrequent travel with overnight stay. Danes 15-85 years-old travel in average 5.5 long distance travel...

  20. Travel patterns in China.

    Directory of Open Access Journals (Sweden)

    Tini Garske

    Full Text Available The spread of infectious disease epidemics is mediated by human travel. Yet human mobility patterns vary substantially between countries and regions. Quantifying the frequency of travel and length of journeys in well-defined population is therefore critical for predicting the likely speed and pattern of spread of emerging infectious diseases, such as a new influenza pandemic. Here we present the results of a large population survey undertaken in 2007 in two areas of China: Shenzhen city in Guangdong province, and Huangshan city in Anhui province. In each area, 10,000 randomly selected individuals were interviewed, and data on regular and occasional journeys collected. Travel behaviour was examined as a function of age, sex, economic status and home location. Women and children were generally found to travel shorter distances than men. Travel patterns in the economically developed Shenzhen region are shown to resemble those in developed and economically advanced middle income countries with a significant fraction of the population commuting over distances in excess of 50 km. Conversely, in the less developed rural region of Anhui, travel was much more local, with very few journeys over 30 km. Travel patterns in both populations were well-fitted by a gravity model with a lognormal kernel function. The results provide the first quantitative information on human travel patterns in modern China, and suggest that a pandemic emerging in a less developed area of rural China might spread geographically sufficiently slowly for containment to be feasible, while spatial spread in the more economically developed areas might be expected to be much more rapid, making containment more difficult.

  1. Travelling diabetics.

    Science.gov (United States)

    Chełmińska, Katarzyna; Jaremin, Bogdan

    2002-01-01

    During the past several decades, the number of both business and tourist travels has greatly increased. Among them are persons suffering from chronic diseases, including diabetics for whom travels pose the additional health-hazard. Irrespective of better education, self-control and constantly improving quality of specialistic equipment available, diabetics still are the group of patients requiring particular attention. In the case of travelling diabetics, problems may occur concerning the transport and storage of insulin, as well as control of glycaemia, all caused by irregularity of meals, variable diet, physical activity, stress, kinetosis (sea voyages), and the change of time zones. The travel may as well evoke ailments caused by the change of climate and concomitant diseases such as traveller's diarrhoea, malaria, etc. Apart from avoiding glycaemia fluctuations, important for retaining health of diabetics is the prevention of other diseases and carrying the necessary drugs.

  2. Zero Energry Travel

    CERN Document Server

    Ahmad, Othman; Chekima, Ali

    2011-01-01

    It is fundamentally possible to travel with zero energy based on Newton Laws of Motion. According to the first law of motion, a body will continue to travel for infinite distance unless it is acted upon by another force. For a body in motion, the force which stops perpetual motion is friction. However, there are many circumstances that friction is zero, for example in space, where there is vacuum. On earth, gravity makes objects to be in constant contact with each other generating friction but technology exists to separate them in the air using powerful magnetic forces. At low speeds, the friction caused by air is minimal but we can create vacuum even on land for high speed travel. Another condition for travelling is for it to stop at its destination. On land, we can recover the kinetic energy back into electrical energy using brushless permanent magnet generators. These generators can also convert electric energy into kinetic energy in order to provide motion. This article reviews technologies that will allo...

  3. [Adventure travel].

    Science.gov (United States)

    Beck, Bernhard R

    2013-06-01

    Extreme travelling experiences appear to be a quite popular kick offered by tourist operators and sought by some travellers. But some travellers expose themselves to increased risk also during normal holidays, either voluntarily by booking hikes or tours leading them to adventurous locations or to unexpectedly encountering dangerous situations. In planned adventures, precise information in advance, good physical condition, careful planning, and profound medical preparation may contribute to a less hazardous adventure. Advising medical persons may need an expert consultation for specific topics in order to optimise the preparation. Based on three specific environmental situations (jungle, desert, and cave) the specific conditions, dangers and some medical aspects are outlined. PMID:23732454

  4. Travelers' Diarrhea

    Science.gov (United States)

    ... Visiting Friends and Family in Areas with Chikungunya, Dengue, or Zika Travel to the Olympics Infographic: Olympic ... East, Africa, Mexico, and Central and South America. Prevention In otherwise healthy adults, diarrhea is rarely serious ...

  5. Travelling Concepts

    DEFF Research Database (Denmark)

    Simonsen, Karen-Margrethe

    2013-01-01

    Review of "Travelling Concepts, Metaphors, and Narratives: Literary and Cultural Studies in an Age of Interdisciplinary Research" ed. by Sibylle Baumgarten, Beatrice Michaelis and Ansagar Nünning, Trier; Wissenschaftlicher Verlag Trier, 2012......Review of "Travelling Concepts, Metaphors, and Narratives: Literary and Cultural Studies in an Age of Interdisciplinary Research" ed. by Sibylle Baumgarten, Beatrice Michaelis and Ansagar Nünning, Trier; Wissenschaftlicher Verlag Trier, 2012...

  6. Effectiveness of Motorcycle speed controlled by speed hump

    Directory of Open Access Journals (Sweden)

    Pornsiri Urapa

    2014-09-01

    Full Text Available Speed humps are one of the traffic calming measures widely accepted to control vehicle speed in the local road. Humps standards from the western countries are designed mainly for the passenger car. This study, therefore, aims to reveal the effectiveness of speed hump to control the motorcycle speed. This study observes the free-flow speed of the riders at the total of 20 speed bumps and humps. They are 0.3-14.8 meter in width and 5-18 centimeter in height. The results reveal that the 85th percentile speeds reduce 15-65 percent when crossing the speed bumps and speed humps. Besides, this study develops the speed model to predict the motorcycle mean speed and 85th percentile speed. It is found that speed humps follow the ITE standard can control motorcycle crossing speeds to be 25-30 Kph which are suitable to travel on the local road.

  7. Travelling 'green': is tourists' happiness at stake?

    NARCIS (Netherlands)

    Nawijn, J.; Peeters, P.M.

    2010-01-01

    Several western governments have implemented environmental policies which increase the cost of air travel. Such policies aim to reduce the impact of air travel on climate change, but at the same time they restrict tourists in their travels. This study examines the extent to which the average tourist

  8. Revenue Management Model for High-Speed Railway Based on Traveler Choice%基于旅客选择的高速铁路客运收益管理研究

    Institute of Scientific and Technical Information of China (English)

    张力; 蓝伯雄

    2012-01-01

    本文旨在探讨收益管理在高速铁路客运中的应用,给出了存在多级票价时,考虑旅客选择行为的铁路客运收益管理模型,优化结果能够同时给出发车指令和座位出售限制.利用模拟数据对模型进行了数值试验,表明在不同路段长度下,考虑旅客选择行为的总收益较需求独立模型均有所提高,且随着票价等级增多而增长.%This paper deals with the application of revenue management to high-speed railway industry. We present a railway passenger revenue management model considering traveler choice behavior in case of multi-fare. The result gives the booking limits of each fare class and train scheduling as well. Numerical experiments on simulation data show that total revenue of the choice model is higher than those of independent demand, and surges with the increase of fare classes.

  9. Travel Fever

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China to become the world’s No.1 tourist destination by 2015 May 19 is a special day in China’s history. On that day 400 years ago,Xu Xiake (1587-1641),wellknown geographer,traveler and explorer of the Ming Dynasty (1368-1644),started a lifelong journey,leading to the publication of the monumental Xu Xiake’s Travel Notes,known for its detailed and accurate geographical information. The book also provided valuable insight into local customs and habits.

  10. Speed management : enforcement and new technologies.

    NARCIS (Netherlands)

    Wegman, F.C.M. & Goldenbeld, C.

    2006-01-01

    Due to the massive character of speeding and inappropriate travel speeds, speed management continues to be an important and challenging policy area. Estimates are that in about a quarter to one third of fatal crashes excessive speeds are involved, making speed one of the crucial factors in road safe

  11. Measuring Workplace Travel Behaviour: Validity and Reliability of Survey Questions

    OpenAIRE

    Petrunoff, Nicholas A.; Huilan Xu; Chris Rissel; Li Ming Wen; van der Ploeg, Hidde P

    2013-01-01

    Background. The purpose of this study was to assess the (previously untested) reliability and validity of survey questions commonly used to assess travel mode and travel time. Methods. Sixty-five respondents from a staff survey of travel behaviour conducted in a south-western Sydney hospital agreed to complete a travel diary for a week, wear an accelerometer over the same period, and twice complete an online travel survey an average of 21 days apart. The agreement in travel modes between the ...

  12. Empirical Study of Travel Time Estimation and Reliability

    OpenAIRE

    Ruimin Li; Huajun Chai; Jin Tang

    2013-01-01

    This paper explores the travel time distribution of different types of urban roads, the link and path average travel time, and variance estimation methods by analyzing the large-scale travel time dataset detected from automatic number plate readers installed throughout Beijing. The results show that the best-fitting travel time distribution for different road links in 15 min time intervals differs for different traffic congestion levels. The average travel time for all links on all days can b...

  13. Traveler's Diarrhea

    Science.gov (United States)

    ... You also can take a medicine called loperamide (brand name: Imodium). However, if you have bloody diarrhea, ... traveler’s diarrhea? Is traveler’s diarrhea common in the country I’m traveling to? If I get traveler’s ...

  14. Weak energy condition violation and superluminal travel

    OpenAIRE

    Lobo, Francisco; Crawford, Paulo

    2002-01-01

    Recent solutions to the Einstein Field Equations involving negative energy densities, i.e., matter violating the weak-energy-condition, have been obtained, namely traversable wormholes, the Alcubierre warp drive and the Krasnikov tube. These solutions are related to superluminal travel, although locally the speed of light is not surpassed. It is difficult to define faster-than-light travel in generic space-times, and one can construct metrics which apparently allow superluminal travel, but ar...

  15. [Pregnancy and traveling].

    Science.gov (United States)

    Walentiny, C

    2009-03-01

    The second trimester is the safest time for travelling, because the pregnant woman feels generally most at ease and the risk of spontaneous abortion and pre-term labour is very low. Possible risks must be discussed with the obstetrician before travelling. If the pregnancy is uncomplicated most airlines allow flying up to the 36th (domestic flights) and 35th (international flights) week of gestation. Unless the fetal oxygen supply is already impaired at ground level due to an underlying disease, flying does not pose a risk of fetal hypoxia. Radiation exposure during a long distant flight is low compared to the average annual exposure dosage, but the risk of thrombosis is increased. Altitudes up to 2,500 m pose no problem. Sufficient time to acclimatize must be taken when travelling to high altitudes and exercise kept to a minimum. Scuba diving is contraindicated. Since only a few drugs are completely safe during pregnancy a thorough risk/benefit evaluation is mandatory. Treatment of infections can be considerably complicated, but any necessary treatment should not be withheld because of the fear of potential fetal injury. Good knowledge of local medical resources is essential before travelling. Several personal protective measures minimize the risk of infection: food and water precautions, protection from insect bites and avoidance of crowds, unsafe sex and, if need be, freshwater. Many vaccinations are recommended for travellers. However, live vaccines are contraindicated in pregnant women because of theoretical considerations. Exceptionally a yellow fever vaccination may be given after the first trimester. Killed, inactivated or polysaccharide vaccines can be given after the first trimester after a thorough risk/benefit evaluation. Because of the potentially devastating effect of malaria to the mother and the child, travelling to endemic malaria regions should be avoided. If the risk of infection is high chemoprophylaxis with mefloquine is indicated. In low

  16. Travel/Travelers and Parasitic Diseases

    Science.gov (United States)

    ... Tropical Diseases Laboratory Diagnostic Assistance [DPDx] Parasites Home Travel/Travelers Recommend on Facebook Tweet Share Compartir International ... The Parasitic Illnesses That Can Be Acquired During Travel* Contaminated Food and Water More Common giardiasis cryptosporidiosis ...

  17. Scouting the spectrum for interstellar travellers

    CERN Document Server

    Garcia-Escartin, Juan Carlos

    2012-01-01

    Advanced civilizations capable of interstellar travel, if they exist, are likely to have advanced propulsion methods. Spaceships moving at high speeds would leave a particular signature which could be detected from Earth. We propose a search based on the properties of light reflecting from objects travelling at relativistic speeds. Based on the same principles, we also propose a simple interstellar beacon with a solar sail.

  18. Travel during Pregnancy

    Science.gov (United States)

    ... Management Education & Events Advocacy For Patients About ACOG Travel During Pregnancy Home For Patients Search FAQs Travel ... Travel During Pregnancy FAQ055, February 2016 PDF Format Travel During Pregnancy Pregnancy When is the best time ...

  19. Towards a Metropolitan Fundamental Diagram Using Travel Survey Data.

    Directory of Open Access Journals (Sweden)

    Kai Wang

    Full Text Available Using travel diary data from 2000-2001 and 2010-2012 this research examines fundamental traffic relationships at the metropolitan level. The results of this paper can help to explain the causes of some traffic phenomena. Network average speed by time of day can be explained by trip length and cumulative number of vehicles on the road. A clockwise hysteresis loop is found in the Metropolitan Fundamental Diagram in the morning period and a reverse process happens in the afternoon.

  20. Superconducting traveling wave accelerators

    International Nuclear Information System (INIS)

    This note considers the applicability of superconductivity to traveling wave accelerators. Unlike CW operation of a superconducting standing wave or circulating wave accelerator section, which requires improvement factors (superconductor conductivity divided by copper conductivity) of about 106 in order to be of practical use, a SUperconducting TRaveling wave Accelerator, SUTRA, operating in the pulsed mode requires improvement factors as low as about 103, which are attainable with niobium or lead at 4.2K, the temperature of liquid helium at atmospheric pressure. Changing from a copper traveling wave accelerator to SUTRA achieves the following. (1) For a given gradient SUTRA reduces the peak and average power requirements typically by a factor of 2. (2) SUTRA reduces the peak power still further because it enables us to increase the filling time and thus trade pulse width for gradient. (3) SUTRA makes possible a reasonably long section at higher frequencies. (4) SUTRA makes possible recirculation without additional rf average power. 8 references, 6 figures, 1 table

  1. Ocean acoustic tomography - Travel time biases

    Science.gov (United States)

    Spiesberger, J. L.

    1985-01-01

    The travel times of acoustic rays traced through a climatological sound-speed profile are compared with travel times computed through the same profile containing an eddy field. The accuracy of linearizing the relations between the travel time difference and the sound-speed deviation at long ranges is assessed using calculations made for two different eddy fields measured in the eastern Atlantic. Significant nonlinearities are found in some cases, and the relationships of the values of these nonlinearities to the range between source and receiver, to the anomaly size associated with the eddies, and to the positions of the eddies are studied. An analytical model of the nonlinearities is discussed.

  2. Easy Travel

    Institute of Scientific and Technical Information of China (English)

    Francois; Essomba

    2011-01-01

    A common visa for six Central African countries boosts tourism FOR a region that is made up of six countries, the Economic and Monetary Community of Central Africa(CEMAC) has less than 2 million annual cross border arrivals according to official statistics. Cameroon,the Republic of the Congo, Gabon,Equatorial Guinea,Central African Republic(CAR) and Chad make up this group,whose regional travel statistics are extremely low by international standards.Cameroon received only 580,000 visitors in 2010.

  3. Estimation Models for Average Speed of Traffic Flow Based on GPS Data of Taxi%基于出租车GPS数据的路段平均速度估计模型

    Institute of Scientific and Technical Information of China (English)

    姜桂艳; 常安德; 李琦; 伊峰

    2011-01-01

    The existing average speed estimation models based on GPS ( global positioning system) data of taxis are not applicable where high precision and low cost are of necessities. Two traditional models, namely a time integral model and a time interpolation model, based on the GPS data of taxis were modified, and the two modified models were combined to form a hybrid model. The three new models were verified using GPS data of taxis obtained from a part of road network of a large city. The results shown that the estimating precisions of the two modified models increased by 1. 5% and 19.7% , respectively, compared with the original time integral model and time interpolation model, and those of the hybrid model by 2. 8% and 8. 8% , respectively, compared with the two modified models.%为了解决现有基于GPS数据的路段平均速度估计模型应用条件苛刻、难以满足低成本和高精度信息需求问题,考虑不同类型GPS车辆运行特征,设计了两个基于出租车GPS数据估计路段平均速度的改进模型.基于两个改进模型,设计了路段平均速度的融合估计方法.用某城市局部路网的出租车GPS数据验证两个改进模型,并与传统模型进行了对比分析.结果表明,在不增加成本的条件下,两个改进模型的估计精度分别比传统模型提高了1.5%与19.7%;融合估计方法的精度比两个改进模型分别提高了2.8%与8.8%.

  4. Travel counseling for the elderly traveler.

    Science.gov (United States)

    Schindler, Kasey J

    2005-01-01

    As the baby boomer's generation retirees, many will have the time and money to travel abroad to see the world's exotic wonders or visit family and friends. When the travelers are elderly, they are particularly vulnerable to the effects of travel. Healthcare professionals are responsible for counseling elders on travel health based on their medical history, destination, method of transportation, and exposure risks. Important areas of travel counseling include preparing for travel, air travel, safety, sun and heat, insect precautions, food and water precautions, and vaccinations. PMID:16271122

  5. Weak energy condition violation and superluminal travel

    CERN Document Server

    Lobo, F; Lobo, Francisco; Crawford, Paulo

    2003-01-01

    Recent solutions to the Einstein Field Equations involving negative energy densities, i.e., matter violating the weak-energy-condition, have been obtained, namely traversable wormholes, the Alcubierre warp drive and the Krasnikov tube. These solutions are related to superluminal travel, although locally the speed of light is not surpassed. It is difficult to define faster-than-light travel in generic space-times, and one can construct metrics which apparently allow superluminal travel, but are in fact flat Minkowski space-times. Therefore, to avoid these difficulties it is important to provide an appropriate definition of superluminal travel.

  6. Accurate estimation of indoor travel times

    DEFF Research Database (Denmark)

    Prentow, Thor Siiger; Blunck, Henrik; Stisen, Allan;

    2014-01-01

    are collected within the building complex. Results indicate that InTraTime is superior with respect to metrics such as deployment cost, maintenance cost and estimation accuracy, yielding an average deviation from actual travel times of 11.7 %. This accuracy was achieved despite using a minimal-effort setup......The ability to accurately estimate indoor travel times is crucial for enabling improvements within application areas such as indoor navigation, logistics for mobile workers, and facility management. In this paper, we study the challenges inherent in indoor travel time estimation, and we propose...... the InTraTime method for accurately estimating indoor travel times via mining of historical and real-time indoor position traces. The method learns during operation both travel routes, travel times and their respective likelihood---both for routes traveled as well as for sub-routes thereof. In...

  7. Travel insurance and health.

    Science.gov (United States)

    Leggat, P A; Carne, J; Kedjarune, U

    1999-12-01

    Travel insurance normally underwrites travel, medical, and dental expenses incurred by travelers abroad and arranges aeromedical evacuation of travelers under conditions specified by the travel insurance policy. Because of the costs of medical and dental treatment abroad and the high cost associated with aeromedical evacuation, all travelers should be advised of the need for comprehensive travel insurance and be advised to read their policies carefully to see what is covered and to check for any exclusions. In particular, those travelers who have known preexisting conditions, who are working overseas, or who are going to undertake any form of hazardous recreational pursuit may need to obtain a special travel insurance policy, which may attract a higher premium. Conservatively, it is estimated that between 30-50% of travelers become ill or injured whilst traveling. Relative estimated monthly incidence rates of various health problems have been compiled elsewhere. The risk of severe injury is thought to be greater for people when traveling abroad. These risks should be covered by travel insurance to protect the traveler, however it is not known what proportion of travel agents or airlines give advice routinely on travel insurance. Travel insurance is the most important safety net for travelers in the event of misadventure, and should be reinforced by travel health advisers. Although only 4% of general practitioners (GPs) in a late 1980's study in the United Kingdom would advise a traveler going to Turkey about travel insurance,4 more recent studies have shown about 60% of GPs in New Zealand and 39% of travel clinics worldwide usually advised travelers concerning travel insurance. In addition, 54% of GPs in New Zealand usually also advised travelers about finding medical assistance abroad, but only 19% of GPs recommended travel insurance companies as a source of medical assistance while traveling. PMID:10575173

  8. Overreporting vs. Overreacting: Commuters' Perceptions of Travel Times

    OpenAIRE

    Peer, Stefanie; Knockaert, Jasper; Koster, Paul; Verhoef, Erik

    2013-01-01

    We asked participants of a large-scale, real-life peak avoidance experiment to provide estimates of their average in-vehicle travel time for their morning commute. Comparing these reported travel times to the corresponding actual travel times, we find that travel times are overstated by a factor of 1.5 on average. We show that driver- and link-speci c characteristics partially explain the overstating. Using stated and revealed preference data, we investigate whether the driverspecific reporti...

  9. Development of control strategy of variable speed limits for improving traffic operations at freeway bottlenecks

    Institute of Scientific and Technical Information of China (English)

    李志斌; 刘攀; 王炜; 徐铖铖

    2014-01-01

    A control strategy of variable speed limits (VSL) was developed to reduce the travel time at freeway recurrent bottleneck areas. The proposed control strategy particularly focused on preventing the capacity drop and increasing the discharge flow. A cell transmission model (CTM) was developed to evaluate the effects of the proposed VSL control strategy on the traffic operations. The results show that the total travel time is reduced by 25.5% and the delay is reduced by 56.1%. The average travel speed is increased by 34.3% and the queue length is reduced by 31.0%. The traffic operation is improved by the proposed VSL control strategy. The way to use the proposed VSL control strategy in different types of freeway bottlenecks was also discussed by considering different traffic flow characteristics. It is concluded that the VSL control strategy is effective for merge bottlenecks but is less effective for diverge bottlenecks.

  10. Travelling ionospheric disturbance over California mid 2000

    Directory of Open Access Journals (Sweden)

    M. Hawarey

    2006-01-01

    Full Text Available In this paper, the GPS data collected by more than 130 permanent GPS stations that belong to the Southern California Integrated GPS Network (SCIGN around the launch of a Minuteman-II missile on 8 July 2000 (UTC is processed to reveal traveling ionospheric disturbance (TID all over the network on average 15 min after the launch. This TID was initially perceived to be excited by the launch itself, but this conclusion is challenged by the propagation direction. This is because this TID seems to travel towards the air force base from where the launch took place, not far away from it. This challenge is based on the assumption that TID is occurring at one single ionospheric altitude. While the nature of ionosphere supports such horizontally-guided propagation, multi-altitude ionospheric pierce points are hypothesized, which would support the suggestion that detected TID is excited by the missile launch itself, despite the apparent reverse direction of propagation. The overall analysis rules out any extra-terrestrial sources like solar flares, or seismic sources like earthquakes, which confirms the conclusion of TID excitation by the launch. There is apparent coherence of the TID for about 45 min and the propagation speed of TID within the layer of ionosphere is calculated to be approximately equal to 1230 m/s. While the usual assumption for TID is that they occur around an altitude of 350 km, such sound speed can only occur at much higher altitudes. Further research is recommended to accurately pinpoint the ionospheric pierce points and develop an algorithm to locate the source of TID in case it is totally unknown.

  11. Recommended vaccines for international travelers to India

    OpenAIRE

    Verma, Ramesh; Khanna, Pardeep; Chawla, Suraj

    2014-01-01

    India's tourism industry generated 6.6% of the nation's Gross Domestic Product (GDP) during 2012. International travel to India is predicted to grow at an average annual rate of ∼8% over the next decade. The number of foreign tourists has increased by 9% to 5.8 million. Approximately 8% of travelers to developing countries require medical care during or after travel; the main diagnoses are vaccine-preventable diseases. Travelers to India can be exposed to various infectious diseases; water-bo...

  12. Home range and travels

    Science.gov (United States)

    Stickel, L.F.; King, John A.

    1968-01-01

    . Peromyscus generally used and maintained several or many different home sites and refuges in various parts of their home ranges, and frequently shifted about so that their principal activities centered on different sets of holes at different times. Once established, many Peromyscus remained in the same general area for a long time, perhaps for the duration of their lives. Extent of their travels in different directions and intensity of use of different portions of their home ranges varied within a general area in response to habitat changes, loss of neighbors, or other factors. Various authors have obtained both direct and indirect evidence of territoriality, in some degree, among certain species of Peromyscus. Young mice dispersed from their birth sites to establish home ranges of their own. Adults also sometimes left their home areas; some re-established elsewhere; others returned after exploratory travels. Most populations contained a certain proportion of transients; these may have been wanderers or individuals exploring out from established home ranges or seeking new ones. When areas were depopulated by removal trapping, other Peromyscus invaded. Invasion rates generally followed seasonal trends of reproduction and population density. Peromyscus removed from their home areas and released elsewhere returned home from various distances, but fewer returned from greater distances than from nearby; speed of return increased with successive trials. The consensus from present evidence is that ho-ming is made possible by a combination of random wandering and familiarity with a larger area than the day-to-day range. Records of juvenile wanderings during the dispersal phase and of adult explorations very nearly encompassed the distances over which any substantial amount of successful homing occurred. Methods of measuring sizes of home ranges and the limitations of these measurements were discussed in brief synopsis. It was co

  13. Travel time and travel cost in European air travel

    OpenAIRE

    Dusek, Tamas

    2012-01-01

    The aim of the study is to examine two issues of consumer air travel accessibility in Europe, namely flight time and ticket costs. The first part of the paper discusses the various methodological problems of creating time matrix and cost matrix of air travel. Because of problems of conceptualizing of the air travel network and the modifiable areal unit problem the analysis is conducted on several spatial levels. The smallest network consists of 15 busiest airports and the largest network has ...

  14. Childhood and Travel Literature.

    Science.gov (United States)

    Espey, David

    If children are not present in most travel literature--precisely because the genre has most typically been the domain of solitary male travelers who are escaping domestic obligation, routine, the familiar, and the family--they nevertheless are an integral part of the genre. The traveler is in many ways a child, an innocent abroad. Traveler writers…

  15. Why Does Light Have a Finite Speed?

    Science.gov (United States)

    Brusca, Stephen

    1985-01-01

    Examines the question "Why does light travel at speed c?", dispelling the widespread qualitative notion that the speed of light results from time delays in the interaction of electric and magnetic fields. Also presents information by which readers can work on their own qualitative insights concerning the speed of light. (JN)

  16. Travel-related illness.

    Science.gov (United States)

    Ziegler, Carol C

    2013-06-01

    Travel abroad for business and pleasure should be safe and meaningful for the traveler. To assure that safe experience, certain processes should be considered before travel. A thorough pretravel health assessment will offer patients and health care providers valuable information for anticipatory guidance before travel. The destination-based risk assessment will help determine the risks involved in travel to specific locations and guide in the development of contingency plans for all travelers, especially those with chronic conditions. Diseases are more prevalent overseas, and immunizations and vaccinations are all important considerations for persons traveling abroad. PMID:23692948

  17. Traveling waves for monomer chains with precompression

    International Nuclear Information System (INIS)

    In the present work, we complement our earlier study on the subject of granular crystals in the purely nonlinear limit (no precompression) by considering the case where an underlying linear limit exists (finite precompression). In the latter context, we explicitly prove the existence of supersonic travelling waves, which are smooth, positive and exponentially localized. While numerical computations suggest that the cutoff point for the existence of such exponentially decaying waves is exactly the speed of sound in the system, we can not establish this result sharply within our variational technique but can only prove a relevant upper bound on the propagation speed of bell-shaped travelling waves in the strain variables. (paper)

  18. Relationship of solar wind parameters to continuous, dayside, high latitude traveling ionospheric convection vortices

    International Nuclear Information System (INIS)

    In a companion paper the authors have shown that many continuous, dayside, high latitude magnetic pulsations are caused by steady, traveling ionospheric convection vortices (McHenry et al. this issue). A variety of evidence indicates that these vortices are the ionospheric signatures of the Kelvin-Helmholtz instability at the inner edge of the magnetospheric boundary layer. In this paper the authors present the results of a statistical study of the occurrence of these vortices and the upstream solar wind parameters observed by the IMP 8 spacecraft. Surveying fifty days of Greenland west coast chain magnetometer data indicates this class of pulsations is most likely to be detected post local noon and when the solar wind speed is low. However, it is possible that observational factors significantly affect the detection of the vortices. the slow solar wind might create large, slow moving traveling vortices of steady strength which are easiest to identify. Little correlation is found between the average IMF and the probability of detecting the vortices. They also find a strong correlation between the frequency of dayside pulsations and the solar wind speed. This suggests that many pulsations are caused by traveling ionospheric current systems that map to the vicinity of the flows in the magnetospheric boundary layer. Periods also exist when the IMF is variable and large pulsations with 5 to 20 min period exist. These pulsations are not caused by traveling ionospheric vortices but are likely to be the result of rapid variations of the large scale field-aligned cusp currents

  19. Commuters' valuation of travel time variability in Barcelona

    OpenAIRE

    Matas i Prat, Anna; Asensio Ruiz de Alda, Francisco Javier

    2007-01-01

    The value given by commuters to the variability of travel times is empirically analysed using stated preference data from Barcelona (Spain). Respondents are asked to choose between alternatives that differ in terms of cost, average travel time, variability of travel times and departure time. Different specifications of a scheduling choice model are used to measure the influence of various socioeconomic characteristics. Our results show that travel time variability.

  20. Measuring Workplace Travel Behaviour: Validity and Reliability of Survey Questions

    Directory of Open Access Journals (Sweden)

    Nicholas A. Petrunoff

    2013-01-01

    Full Text Available Background. The purpose of this study was to assess the (previously untested reliability and validity of survey questions commonly used to assess travel mode and travel time. Methods. Sixty-five respondents from a staff survey of travel behaviour conducted in a south-western Sydney hospital agreed to complete a travel diary for a week, wear an accelerometer over the same period, and twice complete an online travel survey an average of 21 days apart. The agreement in travel modes between the self-reported online survey and travel diary was examined with the kappa statistic. Spearman’s correlation coefficient was used to examine agreement of travel time from home to workplace measured between the self-reported online survey and four-day travel diary. Moderate-to-vigorous physical activity (MVPA time of active and nonactive travellers was compared by t-test. Results. There was substantial agreement between travel modes (K=0.62, P<0.0001 and a moderate correlation for travel time (ρ=0.75, P<0.0001 reported in the travel diary and online survey. There was a high level of agreement for travel mode (K=0.82, P<0.0001 and travel time (ρ=0.83, P<0.0001 between the two travel surveys. Accelerometer data indicated that for active travellers, 16% of the journey-to-work time is MVPA, compared with 6% for car drivers. Active travellers were significantly more active across the whole workday. Conclusions. The survey question “How did you travel to work this week? If you used more than one transport mode specify the one you used for the longest (distance portion of your journey” is reliable over 21 days and agrees well with a travel diary.

  1. Effect of travel speed and suction carried by a pneumatic planter on seed dosage and germination Efecto de la velocidad de avance y de la succión de una sembradora neumática en la dosificación y germinación de semillas

    Directory of Open Access Journals (Sweden)

    Herrera G Óscar A.

    2006-09-01

    Full Text Available

    The effect of the travel speed and suction carried by the John Deere 7300 pneumatic planterʼs vacuum pump on ICA-305 corn, FUNKʼS HW-1758 sorghum, and Soyica P-34 soybean seeds dosage, germination, and vigor was studied; five travel speeds were assessed (2, 4, 6, 8 and 10 km/h and two vacuum pump work pressures (-1241.4 and -1738.0 Pa, at the sprocket combination 16/28. Seed weight (g supplied and seed of variance distribution in two lineal meters, seed feasibility by germination and vigor tests, were determined. Analysis of variance for means of the variable and four regression models (linear, quadratic, cubic and quadruple were applied. The linear regression model selected to explain correlation lead to conclude that travel speed of plant equipment do not affect seed dosage at two working pressures. No effect was found of planting work pressure on seed dosage. No effect was found of planting work pressure and travel speed on corn, sorghum, and soybean seed germination and germinated plantules vigor.

    Key words: corn, sorghum and soybean planting; pneumatic planter; planting travel speed; planting work pressure; seeds dosage and germination.

    Se estudió el efecto en maíz (ICA-305, sorgo (FUNKʼS HW-1758 y soya (Soyica P-34, de cinco (5 velocidades de marcha (2, 4, 6, 8 y 10 km/h y dos presiones de trabajo de la bomba de vacío (-1241.4 y -1738.0 Pa; en la relación de piñones 16/28 de la caja de cambios de la sembradora neumática John Deere 7300. Se determinó el peso dosificado y la distribución de la semilla en dos metros lineales; la viabilidad mediante pruebas de germinación y el vigor de plántulas germinadas. Se empleó análisis de varianza para las medias de las variables y se probaron cuatro modelos de regresión (lineal, cuadrático, cúbico y cuártico. En el modelo de regresión lineal elegido

  2. Macroscopic travel time reliability diagrams for freeway networks

    OpenAIRE

    Tu, H. (Hongmin); Li, H.; Van Lint, J.W.C.; Knoop, V.L.; Sun, L

    2013-01-01

    Travel time reliability is considered to be one of the key indicators of transport system performance. Knowledge of the mechanisms of travel time unreliability enables the derivation of explanatory models with which travel time reliability can be predicted and utilized in traffic management. Inspired by the macroscopic fundamental diagram (MFD), describing the relationship between production (average flow completing the trips) and vehicle accumulation (average density) in a traffic network, t...

  3. Travelling with HIV

    DEFF Research Database (Denmark)

    Nielsen, Ulla S; Jensen-Fangel, Søren; Pedersen, Gitte;

    2014-01-01

    BACKGROUND: We aimed to describe travel patterns, extent of professional pre-travel advice and health problems encountered during travel among HIV-infected individuals. METHODS: During a six-month period a questionnaire was handed out to 2821 adult HIV-infected individuals attending any...... of the eight Danish medical HIV care centers. RESULTS: A total of 763 individuals responded. During the previous two years 49% had travelled outside Europe; 18% had travelled less and 30% were more cautious when choosing travel destination than before the HIV diagnosis. Pre-travel advice was sought by only 38......%, and travel insurance was taken out by 86%. However, 29%/74% did not inform the advisor/the insurance company about their HIV status. Nearly all patients on highly active antiretroviral therapy (HAART) were adherent, but 58% worried about carrying HIV-medicine and 19% tried to hide it. Only 19% experienced...

  4. Travelers' Health: Hepatitis E

    Science.gov (United States)

    ... Visiting Friends and Family in Areas with Chikungunya, Dengue, or Zika Travel to the Olympics Infographic: Olympic ... No vaccine is available, nor are drugs for preventing infection. Travelers should avoid drinking unboiled or unchlorinated ...

  5. Risk for Travelers

    Science.gov (United States)

    ... Cow Disease Chronic Wasting Disease (CWD) Prion Diseases Risk for Travelers Recommend on Facebook Tweet Share Compartir ... Jakob Disease (vCJD) by Blood and Blood Products . Risk for Travelers The current risk of acquiring vCJD ...

  6. Travel Inside the Ear

    Science.gov (United States)

    ... Home » Health Info » Hearing, Ear Infections, and Deafness Travel Inside the Ear Video When sound waves reach ... are smaller than an orange seed. It then travels into the inner ear, which is filled with ...

  7. Travel Inside the Ear

    Medline Plus

    Full Text Available ... Home » Health Info » Hearing, Ear Infections, and Deafness Travel Inside the Ear Video When sound waves reach ... are smaller than an orange seed. It then travels into the inner ear, which is filled with ...

  8. Traveling with children

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002427.htm Traveling with children To use the sharing features on this page, please enable JavaScript. Traveling with children presents special challenges. It disrupts familiar ...

  9. Traveling Safely with Medicines

    Science.gov (United States)

    ... Medications Safely My Medicine List How to Administer Traveling Safely with Medicines Planes, trains, cars – even boats ... your trip, ask your pharmacist about how to travel safely with your medicines. Make sure that you ...

  10. Pregnancy and travel

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000608.htm Pregnancy and travel To use the sharing features on this page, ... Most of the time, it is fine to travel while pregnant. As long as you are comfortable ...

  11. End to End Travel

    Data.gov (United States)

    US Agency for International Development — E2 Solutions is a web based end-to-end travel management tool that includes paperless travel authorization and voucher document submissions, document approval...

  12. Travelers' Health: Rubella

    Science.gov (United States)

    ... Visiting Friends and Family in Areas with Chikungunya, Dengue, or Zika Travel to the Olympics Infographic: Olympic ... is time-consuming and expensive. TREATMENT Supportive care. PREVENTION All travelers aged ≥12 months should have evidence ...

  13. Traveling wave laser system

    International Nuclear Information System (INIS)

    A method is described for generating a traveling wave laser pulse of almost unlimited energy content wherein a gain medium is pumped into a traveling wave mode, the traveling wave moving at essentially the velocity of light to generate an amplifying region or zone which moves through the medium at the velocity of light in the presence of directed stimulating radiation, thereby generating a traveling coherent, directed radiation pulse moving with the amplification zone through the gain medium. (U.S.)

  14. Modelling urban travel times

    NARCIS (Netherlands)

    Zheng, F.

    2011-01-01

    Urban travel times are intrinsically uncertain due to a lot of stochastic characteristics of traffic, especially at signalized intersections. A single travel time does not have much meaning and is not informative to drivers or traffic managers. The range of travel times is large such that certain tr

  15. Travelers' Health: Hepatitis A

    Science.gov (United States)

    ... in Travelers Food and Water Getting Health Care Abroad Getting Sick After Travel High Altitudes Hot Climates Humanitarian Aid Workers Humanitarian ... and does not increase the risk for adverse effects, screening for total anti-HAV before travel can be useful in some circumstances to determine ...

  16. Travelers' Health: Scuba Diving

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... PREPARING FOR DIVE TRAVEL Planning for dive-related travel should take ... in health, including injuries or surgery, and medication use. Respiratory ...

  17. Air Travel Health Tips

    Science.gov (United States)

    MENU Return to Web version Air Travel Health Tips Air Travel Health Tips How can I improve plane travel? Most people don't have any problems when ... and dosages of all of your medicines. The air in airplanes is dry, so drink nonalcoholic, decaffeinated ...

  18. Traveling Wave Solutions for Generalized Bretherton Equation

    Institute of Scientific and Technical Information of China (English)

    Amin Esfahani

    2011-01-01

    This paper studies the Generalized Bretherton equation using trigonometric function method including the sech-function method, the sine-cosine function method, and the tanh-function method, and He's semi-inverse method (He's variational method).Various traveling wave solutions are obtained, revealing an intrinsic relationship among the amplitude, frequency, and wave speed.

  19. Traveling Wave Solutions in a Reaction-Diffusion Epidemic Model

    OpenAIRE

    Sheng Wang; Wenbin Liu; Zhengguang Guo; Weiming Wang

    2013-01-01

    We investigate the traveling wave solutions in a reaction-diffusion epidemic model. The existence of the wave solutions is derived through monotone iteration of a pair of classical upper and lower solutions. The traveling wave solutions are shown to be unique and strictly monotonic. Furthermore, we determine the critical minimal wave speed.

  20. Numerical study on the restriction speed of train passing curved rail in cross wind

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The results of numerical investigations of aerodynamic forces and moment coefficients of flow passing a simplified train geometry under different wind speeds are summarized. To compute numerically the different coefficients, the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations, combined with the k-ε turbulence model, were solved using finite volume technique. The pres-sure-velocity fields were coupled using the SIMPLE algorithm. At each iteration the pressure correction was obtained by solving a velocity divergence-derived Poisson-like equation. With the computed aerodynamic forces, the formula of the restriction speed at which the train passed curved rail in cross wind was deduced to analyse the influences of aerodynamic forces on the restriction speed. Results of numerical investigations showed that aerodynamic lift and overturn moment increased more and more rapidly with train speed and wind speed. The enhancement trends showed nonlinear phenomena and enhanced risk in the course of train movement. When the train travels at a high speed and encounters a huge cross wind, the influence involved by nonlinear risk increment will extremely impair safety of train. The following conclusion can also be drawn: The effect of aerodynamic lift makes restriction speed reduce, however, the influences of aerodynamic drag to the limit train speed rest on the direction of wind flow. When the wind blows from inner rail to outer rail, aerodynamic forces shall reduce the restriction speed, by contraries, when the wind blows from outer rail to inner rail, aerodynamic forces shall increase the restriction speed.

  1. Numerical study on the restriction speed of train passing curved rail in cross wind

    Institute of Scientific and Technical Information of China (English)

    CHEN RuiLin; ZENG QingYuan; ZHONG XinGu; XIANG Jun; GUO XiaoGang; ZHAO Gang

    2009-01-01

    The results of numerical investigations of aerodynamic forces and moment coefficients of flow passing a simplified train geometry under different wind speeds are summarized. To compute numerically the different coefficients, the three-dimensional Reynolds-Averaged Navier-Stokes (RANS) equations,combined with the k-ε turbulence model, were solved using finite volume technique. The pressure-velocity fields were coupled using the SIMPLE algorithm. At each iteration the pressure correction was obtained by solving a velocity divergence-derived Poisson-Iike equation. With the computed aerodynamic forces, the formula of the restriction speed at which the train passed curved rail in cross wind was deduced to analyse the influences of aerodynamic forces on the restriction speed. Results of numerical investigations showed that aerodynamic lift and overturn moment increased more and more rapidly with train speed and wind speed. The enhancement trends showed nonlinear phenomena and enhanced risk in the course of train movement. When the train travels at a high speed and encounters a huge cross wind, the influence involved by nonlinear risk increment will extremely impair safety of train.The following conclusion can also he drawn: The effect of aerodynamic lift makes restriction speed reduce, however, the influences of aerodynamic drag to the limit train speed rest on the direction of wind flow. When the wind blows from inner rail to outer rail, aerodynamic forces shall reduce the restriction speed, by contraries, when the wind blows from outer rail to inner rail, aerodynamic forces shall increase the restriction speed.

  2. Polymers on disordered trees, spin glasses, and traveling waves

    Energy Technology Data Exchange (ETDEWEB)

    Derrida, B.; Spohn, H.

    1988-06-01

    We show that the problem of a directed polymer on a tree with disorder can be reduced to the study of nonlinear equations of reaction-diffusion type. These equations admit traveling wave solutions that move at all possible speeds above a certain minimal speed. The speed of the wavefront is the free energy of the polymer problem and the minimal speed corresponds to a phase transition to a glassy phase similar to the spin-glass phase. Several properties of the polymer problem can be extracted from the correspondence with the traveling wave: probability distribution of the free energy, overlaps, etc.

  3. Travelling Ideas, Power and Place

    DEFF Research Database (Denmark)

    Tait, Malcolm; Jensen, Ole B.

    2007-01-01

    A multitude of concepts and ideas have shaped practices in professions such as planning, urban design and urban management.  Now, however, the speed and intensity by which these ideas travel seems historically unprecedented. This paper explores how some of these ideas are formed and circulated...... propose a framework that focuses our understanding of how ideas are translated into new spatial settings.  The examples of the Urban Village and the Business Improvement District will be used to explicate the analytical framework.  In concluding, the paper assesses the utility of the analytic framework...

  4. Finnish travelers' travel motivation : case: Canary Islands

    OpenAIRE

    Jokilehto, Katri

    2012-01-01

    The aim of the thesis was to study the travel motives which lead Finnish people to travel to the Canary Islands and other factors which impact on the holiday decision process and destination choice. The target group for the research was Finnish people and the aim was to study the travel motives of Finns to the Canary Islands and which factors are important for Finnish people to gain a successful holiday. The research was conducted by using internet survey and the collected data was analyzed b...

  5. Travel personae of American pleasure travelers

    DEFF Research Database (Denmark)

    Park, S.; Tussyadiah, Iis; Mazanec, J.A.;

    2010-01-01

    Travel style has been shown to be a useful concept for understanding travelers. In this study it is argued that the portfolio of trips (specifically, the portfolio of various trip styles) one takes can be used to describe his/her overall travel persona. Network analysis was used to examine...... personae which, in turn, are related to their choices of places visited and their response to advertising materials. It was concluded that the framework provided by these findings along with new tools on the Internet offer the potential to develop highly personalized communications with existing...

  6. Signaling cascades modulate the speed of signal propagation through space.

    Directory of Open Access Journals (Sweden)

    Christopher C Govern

    Full Text Available BACKGROUND: Cells are not mixed bags of signaling molecules. As a consequence, signals must travel from their origin to distal locations. Much is understood about the purely diffusive propagation of signals through space. Many signals, however, propagate via signaling cascades. Here, we show that, depending on their kinetics, cascades speed up or slow down the propagation of signals through space, relative to pure diffusion. METHODOLOGY/PRINCIPAL FINDINGS: We modeled simple cascades operating under different limits of Michaelis-Menten kinetics using deterministic reaction-diffusion equations. Cascades operating far from enzyme saturation speed up signal propagation; the second mobile species moves more quickly than the first through space, on average. The enhanced speed is due to more efficient serial activation of a downstream signaling module (by the signaling molecule immediately upstream in the cascade at points distal from the signaling origin, compared to locations closer to the source. Conversely, cascades operating under saturated kinetics, which exhibit zero-order ultrasensitivity, can slow down signals, ultimately localizing them to regions around the origin. CONCLUSIONS/SIGNIFICANCE: Signal speed modulation may be a fundamental function of cascades, affecting the ability of signals to penetrate within a cell, to cross-react with other signals, and to activate distant targets. In particular, enhanced speeds provide a way to increase signal penetration into a cell without needing to flood the cell with large numbers of active signaling molecules; conversely, diminished speeds in zero-order ultrasensitive cascades facilitate strong, but localized, signaling.

  7. Traveling wave laser system

    International Nuclear Information System (INIS)

    The invention broadly involves a method and means for generating a traveling wave laser pulse and is basically analogous to a single pass light amplifier system. However, the invention provides a traveling wave laser pulse of almost unlimited energy content, wherein a gain medium is pumped in a traveling wave mode, the traveling wave moving at essentially the velocity of light to generate an amplifying region or zone which moves through the medium at the velocity of light in the presence of directed stimulating radiation, thereby generating a traveling coherent, directed radiation pulse moving with the amplification zone through the gain medium. (U.S.)

  8. Neutron resonance averaging

    International Nuclear Information System (INIS)

    The principles of resonance averaging as applied to neutron capture reactions are described. Several illustrations of resonance averaging to problems of nuclear structure and the distribution of radiative strength in nuclei are provided. 30 refs., 12 figs

  9. Travelers' Health: Water Disinfection for Travelers

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... the primary disinfectant promoted by CDC and the World Health Organization Safe Water System at a 1. ...

  10. 潜器的随行波减阻降噪贴敷层%Traveling Wave Pasted Layer of High-speed Underwater Vehicles for Reducing Noise and Drag

    Institute of Scientific and Technical Information of China (English)

    张效慈

    2001-01-01

    Enter the 21st century,according to the strategy concept of alongshore,some countries are strengthening the study of posted layers of various submersible shelles.This paper states the geometric shape design and principle of rigid traveling wave pasted layer for reducing noise and drag.%21世纪,随着沿海战战略思想的强化,国际上正在加强各种水下航行器壳体贴敷层的研究。本文给出硬质随行波减阻降噪贴敷层的几何参数设计及原理。

  11. Travelers, keep your yardsticks covered!

    CERN Document Server

    Fraundorf, P B

    1997-01-01

    This note is about introducing classical mechanics in a way that overtly dispels Newtonian misconceptions, minimizing the obstacles to a student's eventual understanding of space-time. This is done by operationally defining all quantities that depend on the observer's state of motion, including time, with respect to a specific ``map-frame'', and by introducing the classical equations for energy, momentum, and velocity-addition as low-speed approximations. It also provides tools for quantifying unidirectional motion at any speed, by students freshly-introduced to constant acceleration. This is done by describing traveler-time as the invariant in the metric equation, presented as a space-time extension of Pythagoras' theorem. Confusions involving frame-dependent simultaneity and length-contraction are minimized by considering only distances measured by observers in the reference map-frame.

  12. Averaging anisotropic cosmologies

    International Nuclear Information System (INIS)

    We examine the effects of spatial inhomogeneities on irrotational anisotropic cosmologies by looking at the average properties of anisotropic pressure-free models. Adopting the Buchert scheme, we recast the averaged scalar equations in Bianchi-type form and close the standard system by introducing a propagation formula for the average shear magnitude. We then investigate the evolution of anisotropic average vacuum models and those filled with pressureless matter. In the latter case we show that the backreaction effects can modify the familiar Kasner-like singularity and potentially remove Mixmaster-type oscillations. The presence of nonzero average shear in our equations also allows us to examine the constraints that a phase of backreaction-driven accelerated expansion might put on the anisotropy of the averaged domain. We close by assessing the status of these and other attempts to define and calculate 'average' spacetime behaviour in general relativity

  13. Travel Software using GPU Hardware

    CERN Document Server

    Szalwinski, Chris M; Dimov, Veliko Atanasov; CERN. Geneva. ATS Department

    2015-01-01

    Travel is the main multi-particle tracking code being used at CERN for the beam dynamics calculations through hadron and ion linear accelerators. It uses two routines for the calculation of space charge forces, namely, rings of charges and point-to-point. This report presents the studies to improve the performance of Travel using GPU hardware. The studies showed that the performance of Travel with the point-to-point simulations of space-charge effects can be speeded up at least 72 times using current GPU hardware. Simple recompilation of the source code using an Intel compiler can improve performance at least 4 times without GPU support. The limited memory of the GPU is the bottleneck. Two algorithms were investigated on this point: repeated computation and tiling. The repeating computation algorithm is simpler and is the currently recommended solution. The tiling algorithm was more complicated and degraded performance. Both build and test instructions for the parallelized version of the software are inclu...

  14. Properties of traveling atmospheric disturbances (TADs) inferred from CHAMP accelerometer observations

    Science.gov (United States)

    Bruinsma, Sean L.; Forbes, Jeffrey M.

    2009-02-01

    Densities derived from accelerometer measurements on the CHAMP satellite near 400 km are used to statistically establish characteristics of large-scale (>1000 km) traveling atmospheric disturbances (TADs). Only TADs that at least propagate from the auroral zone to the equator are analyzed here, and a total of 21 identifiable events are found over the years 2001 2007. The average speed of all TADs, regardless of local time, is 646 ± 122 ms-1. The average speeds on the dayside and nightside are 595 ± 127 ms-1 and 685 ± 106 ms-1, respectively, i.e., the speed appears to be 10% higher on average on the nightside. On six occasions TADs were only detected on the night side; however, TADs on the dayside often appear more distinctly in the data. Moreover, contrary to some theoretical expectations, dayside TADs do not dissipate more readily than night side TADs, although much less are detected between 8 20 solar local time. No clear dependence of TAD amplitude or phase speed with respect to Kp, or rate of increase of Kp, is found.

  15. Differential effects of traffic sign stimuli upon speeding in school zones following a traffic light interruption.

    Science.gov (United States)

    Gregory, Bree; Irwin, Julia D; Faulks, Ian J; Chekaluk, Eugene

    2016-01-01

    Motorists whose journey has been interrupted by signalized traffic intersections in school zones resume their journey at a faster vehicle speed than motorists who have not been required to stop. Introducing a flashing "check speed" sign 70m after the traffic intersections counteracts this interruptive effect. The present study examined which aspects of a reminder sign are responsible for reducing the speeding behavior of interrupted motorists. When a sign that combines both written text and flashing lights was introduced, interrupted motorists did not speed, traveling on average 0.82km/h below the 40km/h speed limit when measured 100m from traffic intersections. Alternatively, when only the flashing lights were visible the interrupted motorists sped 3.36km/h over the 40km/h speed limit. Similar vehicular speeds were observed when only the written text was visible and when no sign was present (7.67 and 7.49km/h over the 40km/h speed limit, respectively). This indicates that static reminder signs add little value over the absence of a school zone reminder sign; the presence of both cues is necessary to fully offset the interruptive effect. This study also highlights the benefit of using exogenous visual cues in traffic signs to capture drivers' attention. These findings have practical implications for the design and use of traffic signs to increase compliance with posted speed limits. PMID:26545011

  16. Uniqueness of Traveling Waves for a Two-Dimensional Bistable Periodic Lattice Dynamical System

    OpenAIRE

    Chin-Chin Wu

    2012-01-01

    We study traveling waves for a two-dimensional lattice dynamical system with bistable nonlinearity in periodic media. The existence and the monotonicity in time of traveling waves can be derived in the same way as the one-dimensional lattice case. In this paper, we derive the uniqueness of nonzero speed traveling waves by using the comparison principle and the sliding method.

  17. TRAVEL AND HOME LEAVE

    CERN Multimedia

    Human Resources Division

    2002-01-01

    Administrative procedures for : Travel to the home station and home leave (hl) Additional travel to the home station (at) Travel to the home station and home leave for family reasons (hlf) As part of the process of simplifying administrative procedures, HR and AS Divisions have devised a new, virtually automatic procedure for payment of travel expenses to the home station. The changes are aimed at rationalising administrative procedures and not at reducing benefits. The conditions of eligibility are unchanged. The new procedure, which will be operational with effect from 1st June 2002, will greatly simplify the administrative processing of claims for travel expenses and the recording of home leaves. Currently, requests for payment are introduced manually into the Advances and Claims system (AVCL) by divisional secretariats. All travel to the home station starting prior to 1st June 2002 will be processed according to the existing system whereas that starting on 1st June and after will be processed accordi...

  18. [Vaccination for international travelers].

    Science.gov (United States)

    Arrazola, M Pilar; Serrano, Almudena; López-Vélez, Rogelio

    2016-05-01

    Traveler's vaccination is one of the key strategies for the prevention of infectious diseases during international travel. The risk of acquiring an infectious disease is determined in each case by the characteristics of the traveler and the travel, so the pre-departure medical advice of the traveler must be individualized. The World Health Organization classifies travelerś vaccines into three groups. - Vaccines for routine use in national immunization programs: Haemophilus influenzae type b, hepatitis B, polio, measles-mumps-rubella, tetanus-diphtheria-whooping a cough, and chickenpox. - Vaccinations required by law in certain countries before to enter them: yellow fever, meningococcal disease and poliomyelitis. - Vaccines recommended depending on the circumstances: cholera, japanese encephalitis, tick-borne encephalitis, meningococcal disease, typhoid fever, influenza, hepatitis A, hepatitis B, rabies and BCG. This review is intended to introduce the reader to the field of international vaccination. PMID:26920587

  19. FORMS OF YOUTH TRAVEL

    OpenAIRE

    Moisã Claudia Olimpia

    2011-01-01

    Taking into account the suite of motivation that youth has when practicing tourism, it can be said that the youth travel takes highly diverse forms. These forms are educational tourism, volunteer programs and “work and travel”, cultural exchanges or sports tourism and adventure travel. In this article, we identified and analyzed in detail the main forms of youth travel both internationally and in Romania. We also illustrated for each form of tourism the specific tourism products targeting you...

  20. Immunizations for foreign travel.

    OpenAIRE

    Hill, D. R.

    1992-01-01

    One of the most important aspects of preparing travelers for destinations throughout the world is providing them with immunizations. Before administering any vaccines, however, a careful health and immunization history and travel itinerary should be obtained in order to determine vaccine indications and contraindications. There are three categories of immunizations for foreign travel. The first category includes immunizations which are routinely recommended whether or not the individual is tr...

  1. Gulliver, Travel, and Empire

    OpenAIRE

    Rawson, Claude

    2012-01-01

    In his article "Gulliver, Travel, and Empire" Claude Rawson analyzes Jonathan Swift's Gulliver's Travels as a central document of European intellectual history. Rawson focuses on the relationship between ethnicity and human identity and asks what constitutes humanity and how individual groups qualify (or not) for human status. Posing teasingly as a "parody" of travel books, it is both a series of voyages and an ethnically widening arc of moral exploration as Book Four at once expresses an amb...

  2. Active Travel - Healthy Lives

    OpenAIRE

    Institute of Public Health in Ireland

    2011-01-01

    Across Ireland, there is considerable scope to replace many short car journeys with walking and cycling which would bring about a range of benefits to health as well as saving money for individuals and society.'Active travel, healthy lives' presents a summary of international evidence on the health and economic benefits of active travel and makes recommendations on how active travel can become a viable, safe and attractive alternative to car use.

  3. Application of Hybrid Encoding Genetic Algorithm on Pickup and Delivery Traveling Salesman Problem with Traffic Conditions

    Directory of Open Access Journals (Sweden)

    S. Patvichaichod

    2011-01-01

    Full Text Available Problem statement: This study deals with the pickup and delivery traveling salesman problem with traffic conditions (PDTSPTW, an extension of the pickup and delivery traveling salesman problem (PDTSP where each customer to be served is associated with two quantities of product to be collected and delivered. Almost PDTSP problems uses distance between each point of customers as Euclidean Distance and are not concerned with other parameters to find minimal cost. Approach: The PDTSPTC concerns more parameters, such as street network and vehicle speed, which results it closer to the real world condition. The study also proposes the developed genetic algorithm called “Hybrid Encoding Genetic Algorithm (HEGA”. The concept is to combine binary encoding and integer encoding together, causing the in complexity of the algorithm structure and the ease of implementation. Results: the HEGA can save the travel cost about 26-57%. It is obviously seen that HEGA in the PDTSPTC test problems result the fast convergence that is about 12-43% and in all, the computational time is under 6 seconds. Conclusion: The HEGA performs quite well when testing a test problem. Computation times are small in all case. The PDTSPTC is closer to real-world conditions than PDTSP. This problem can be applied in logistics immediately if the distance of streets, traffic conditions (average vehicle speed in each street and vehicle conditions (fuel consumption rate and vehicle capacity are known.

  4. Nonlinear traveling waves in confined ferrofluids.

    Science.gov (United States)

    Lira, Sérgio A; Miranda, José A

    2012-11-01

    We study the development of nonlinear traveling waves on the interface separating two viscous fluids flowing in parallel in a vertical Hele-Shaw cell. One of the fluids is a ferrofluid and a uniform magnetic field is applied in the plane of the cell, making an angle with the initially undisturbed interface. We employ a mode-coupling theory that predicts the possibility of controlling the speed of the waves by purely magnetic means. The influence of the tilted magnetic field on the waves shape profile and the establishment of stationary traveling wave structures are investigated. PMID:23214870

  5. [Physical exposure by travelling].

    Science.gov (United States)

    Lange, U

    2011-06-01

    Approximately 40 million Germans travel abroad every year. Air travel is the most frequently used mean of transportation followed by the automobile. During airplane flights rheumatic patients are subjected to numerous physical, biological and climatic factors which can cause stress and adverse effects on general health. Therefore, preventive strategies are helpful to protect against health damage, provided that there is general fitness for air travel. The present article focuses on physical and biological stress as well as psychological aspects during air travel and reviews prophylactic measures. PMID:21533614

  6. [Fever in returning travelers].

    Science.gov (United States)

    Burchard, G

    2014-03-01

    Travel-related illness is most often due to gastrointestinal, febrile, and dermatologic diseases. Fever in a returned traveler demands prompt attention because it may be a manifestation of an infection that could be rapidly progressive and lethal. The approach to the febrile patient should be stepwise and consider travel and exposure history. Malaria is the most common cause of fever in patients returning from Sub-Saharan Africa, whereas dengue is more frequent in travelers from other tropical and subtropical areas. Other serious diseases are typhoid and paratyphoid fever, amebic liver abscess, visceral leishmaniasis, leptospirosis and-rarely-viral hemorrhagic fevers. PMID:24557143

  7. Multimodal Network Equilibrium with Stochastic Travel Times

    Directory of Open Access Journals (Sweden)

    M. Meng

    2014-01-01

    Full Text Available The private car, unlike public traffic modes (e.g., subway, trolley running along dedicated track-ways, is invariably subject to various uncertainties resulting in travel time variation. A multimodal network equilibrium model is formulated that explicitly considers stochastic link capacity variability in the road network. The travel time of combined-mode trips is accumulated based on the concept of the mean excess travel time (METT which is a summation of estimated buffer time and tardy time. The problem is characterized by an equivalent VI (variational inequality formulation where the mode choice is expressed in a hierarchical logit structure. Specifically, the supernetwork theory and expansion technique are used herein to represent the multimodal transportation network, which completely represents the combined-mode trips as constituting multiple modes within a trip. The method of successive weighted average is adopted for problem solutions. The model and solution method are further applied to study the trip distribution and METT variations caused by the different levels of the road conditions. Results of numerical examples show that travelers prefer to choose the combined travel mode as road capacity decreases. Travelers with different attitudes towards risk are shown to exhibit significant differences when making travel choice decisions.

  8. Pre-Travel Medical Preparation of Business and Occupational Travelers

    Science.gov (United States)

    Khan, Nomana M.; Jentes, Emily S.; Brown, Clive; Han, Pauline; Rao, Sowmya R.; Kozarsky, Phyllis; Hagmann, Stefan H.F.; LaRocque, Regina C.; Ryan, Edward T.

    2016-01-01

    Objectives: The aim of the study was to understand more about pre-travel preparations and itineraries of business and occupational travelers. Methods: De-identified data from 18 Global TravEpiNet clinics from January 2009 to December 2012 were analyzed. Results: Of 23,534 travelers, 61% were non-occupational and 39% occupational. Business travelers were more likely to be men, had short times to departure and shorter trip durations, and commonly refused influenza, meningococcal, and hepatitis B vaccines. Most business travelers indicated that employers suggested the pre-travel health consultation, whereas non-occupational travelers sought consultations because of travel health concerns. Conclusions: Sub-groups of occupational travelers have characteristic profiles, with business travelers being particularly distinct. Employers play a role in encouraging business travelers to seek pre-travel consultations. Such consultations, even if scheduled immediately before travel, can identify vaccination gaps and increase coverage. PMID:26479857

  9. The effect of a new intercity expressway based on travel time reliability using electronic toll collection data

    OpenAIRE

    Yamazaki, H.; Uno, N.; Kurauchi, F.

    2012-01-01

    This study describes a method of evaluating the level of service of road networks, based on the average travel time and travel time reliability using electronic toll collection (ETC) data. The authors focused on the variance in travel time under normal circumstances, thus, traffic accidents were removed from the database, and any effect of individual vehicle preference was excluded. They evaluated the travel time distribution based on the average travel time from ETC data for each 15-min inte...

  10. Monitoring travel times in an urban network using video, GPS and Bluetooth

    OpenAIRE

    Jie, L.; van Zuylen, H.J.; Chunhua, L.; Shoufeng, L.

    2011-01-01

    The travel time is an important measure for the quality of traffic. This paper discusses a few methods to measure or estimate the travel time in urban road networks. First of all, it is important to know that urban travel times display a large variation, so that the measurement of a single (average) travel time is not so meaningful. The travel time distribution is more relevant than the single value of the average. This distribution can be obtained from observations of travel times of individ...

  11. Average-energy games

    OpenAIRE

    Bouyer, Patricia; Markey, Nicolas; Randour, Mickael; Larsen, Kim G.; Laursen, Simon

    2015-01-01

    Two-player quantitative zero-sum games provide a natural framework to synthesize controllers with performance guarantees for reactive systems within an uncontrollable environment. Classical settings include mean-payoff games, where the objective is to optimize the long-run average gain per action, and energy games, where the system has to avoid running out of energy. We study average-energy games, where the goal is to optimize the long-run average of the accumulated energy. We show that this ...

  12. Illness in Returned Travellers

    OpenAIRE

    Lawee, D; Scappatura, P.; Gutman, E.

    1989-01-01

    Intercontinental travel is more common now than it has ever been before, and so are travel-related diseases. A thorough history and physical examination provide many clues to possible pathogens, particularly when combined with knowledge of the geographic distribution of specific diseases. Prompt diagnosis and proper treatment are imperative.

  13. Zika Travel Information

    Science.gov (United States)

    ... Partners GeoSentinel Global TravEpiNet Mobile Apps RSS Feeds Zika Travel Information Recommend on Facebook Tweet Share Compartir ... please visit CDC’s Zika website . Traveling soon? Get Zika info on-the-go. Sign up to receive ...

  14. Travelers' Health: Diphtheria

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  15. Travelers' Health: Cryptosporidiosis

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  16. Travelers' Health: Meningococcal Disease

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... preventable serogroups are recognized (see the CDC Travelers’ Health website at www.cdc.gov/travel ). Note that proof of receipt of quadrivalent vaccination ...

  17. Travelers' Health: Mumps

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  18. Travelers' Health: Giardiasis

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  19. Travelers' Health: Sunburn

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  20. Travelers' Health: Pertussis

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  1. Travelers' Health: Coccidioidomycosis

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  2. Travelers' Health: Scabies

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  3. Traveling with Portable Oxygen

    Science.gov (United States)

    ... that is right for you depends on your travel plans, your health requirements, and your personal preferences. Compressed Oxygen Compressed ... notice before your ight if you plan to travel with oxygen. For this ... to review procedures and complete all necessary paperwork required by ...

  4. Travelers' Health: Rabies

    Science.gov (United States)

    ... Animal Safety Blood Clots Bug Bites Business Travel Cold Climates Counterfeit Drugs Cruise Ship Travel Families with ... virus–neutralizing antibody is not necessary in most international ... weight may be small in relation to the size and number of wounds. RIG ...

  5. Travel and transport

    DEFF Research Database (Denmark)

    Bill, Jan; Roesdahl, Else

    2007-01-01

    On the interrelationship between travel, transport and society; on land transport, sea and river transport, and on winter transport;  on the related technologies and their developments......On the interrelationship between travel, transport and society; on land transport, sea and river transport, and on winter transport;  on the related technologies and their developments...

  6. Comparison Of Travel Behaviour In 11 European Countries By Use Of Post- Harmonized European National Travel Surveys

    DEFF Research Database (Denmark)

    Christensen, Linda; Hubert, Jean-Paul; Järvi, Tuuli;

    2014-01-01

    of this paper is to compare travel behaviour among 11 European counties using NTS’s. A post-harmonization process is developed to overcome methodological differences between the surveys and to isolate the differences in travel behaviour. Travel behaviour is measured as mileage, time use, and trips per trip......Travel behaviour comparison among countries has become interesting to understand structural differences in travel behaviour between countries which are important to help developing more sustainable transport policies. To that end, National Travel Surveys (NTS’s) are the most suitable tool. The aim......-maker by mode and differences between countries as a function of travel distance, purpose, license holding, and family type are presented. The results demonstrate that the number of trips per responding trip-maker on an average day are very similar over the countries whereas mileage differs most, from 33 km...

  7. Travel demand forecasting with stated choice data. : Swedish domestic long-distance trips.

    OpenAIRE

    Wang, Qian

    2011-01-01

    The travel demand forecasting capability is affected by the model performance and is restricted by the available modes. The Sampers models being used in long distance travel demand forecasting doesn’t deal with nonlinearity and contains no travel service qualitative variables. The RP models can’t forecast the travel demand of the hypothetical mode of the high speed rail. Meanwhile, the value of time which is an important indicator in cost-benefits evaluation needs to be estimated in more spec...

  8. Land use and travel behaviour: expected effects from the perspective of utility theory and activity-based theories

    OpenAIRE

    Maat, K.; Wee, B.; Stead, D

    2005-01-01

    Assumptions about the effects of various land-use characteristics on travel patterns have found their way into diverse concepts of planning and design, such as the compact city and neighbourhood-design principles. In general, these concepts aim at reducing travel distances and reducing car-travel speed, as it is assumed that as travel distances are shorter, individuals will travel less, and the relative competitive position of slower modes is increased. Although some literature supports the l...

  9. Averaged extreme regression quantile

    OpenAIRE

    Jureckova, Jana

    2015-01-01

    Various events in the nature, economics and in other areas force us to combine the study of extremes with regression and other methods. A useful tool for reducing the role of nuisance regression, while we are interested in the shape or tails of the basic distribution, is provided by the averaged regression quantile and namely by the average extreme regression quantile. Both are weighted means of regression quantile components, with weights depending on the regressors. Our primary interest is ...

  10. On the Averaging Principle

    OpenAIRE

    Fibich, Gadi; Gavious, Arieh; Solan, Eilon

    2012-01-01

    Typically, models with a heterogeneous property are considerably harder to analyze than the corresponding homogeneous models, in which the heterogeneous property is replaced with its average value. In this study we show that any outcome of a heterogeneous model that satisfies the two properties of differentiability and interchangibility is O(\\epsilon^2) equivalent to the outcome of the corresponding homogeneous model, where \\epsilon is the level of heterogeneity. We then use this averaging pr...

  11. Average Angular Velocity

    OpenAIRE

    Van Essen, H.

    2004-01-01

    This paper addresses the problem of the separation of rotational and internal motion. It introduces the concept of average angular velocity as the moment of inertia weighted average of particle angular velocities. It extends and elucidates the concept of Jellinek and Li (1989) of separation of the energy of overall rotation in an arbitrary (non-linear) $N$-particle system. It generalizes the so called Koenig's theorem on the two parts of the kinetic energy (center of mass plus internal) to th...

  12. On Averaging Rotations

    DEFF Research Database (Denmark)

    Gramkow, Claus

    1999-01-01

    In this article two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very offten the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...... approximations to the Riemannian metric, and that the subsequent corrections are inherient in the least squares estimation. Keywords: averaging rotations, Riemannian metric, matrix, quaternion...

  13. Speeding in urban environments: Are the time savings worth the risk?

    Science.gov (United States)

    Ellison, Adrian B; Greaves, Stephen P

    2015-12-01

    Perceived time savings by travelling faster is often cited as a motivation for drivers' speeding behaviour. These time savings, however, come at a cost of significant road injuries and fatalities. While it is known that drivers tend to overestimate the time savings attributable to speeding there is little empirical evidence on how much time drivers genuinely save during day-to-day urban driving and how this relates to speeding-related crashes. The current paper reports on a study to address the lack of empirical evidence on this issue using naturalistic driving data collected from 106 drivers over a period of five weeks. The results show that the average driver saves 26s/day or 2min/week by speeding. More importantly, the cost of these time savings is one fatality for every 24,450h saved by the population on 100km/h roads in dry conditions and one injury for every 2458h saved on the same roads. Full speed compliance - and consequently a dramatic reduction in the road toll - could be achieved through almost imperceptible increases in travel time by each driver. PMID:26476194

  14. Average Bandwidth Allocation Model of WFQ

    Directory of Open Access Journals (Sweden)

    Tomáš Balogh

    2012-01-01

    Full Text Available We present a new iterative method for the calculation of average bandwidth assignment to traffic flows using a WFQ scheduler in IP based NGN networks. The bandwidth assignment calculation is based on the link speed, assigned weights, arrival rate, and average packet length or input rate of the traffic flows. We prove the model outcome with examples and simulation results using NS2 simulator.

  15. Travelling waves in hybrid chemotaxis models

    CERN Document Server

    Franz, Benjamin; Painter, Kevin J; Erban, Radek

    2013-01-01

    Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant) which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybr...

  16. International business travel: impact on families and travellers

    OpenAIRE

    Espino, C.; Sundstrom, S; Frick, H.; Jacobs, M; Peters, M

    2002-01-01

    Objectives: Spouses and staff of the World Bank Group (WBG) were questioned about the impact of international business travel on families and travellers. Dependent variables were self reported stress, concern about the health of the traveller, and negative impact on the family. We hypothesised that several travel factors (independent variables) would be associated with these impacts. These travel factors had to do with the frequency, duration, and predictability of travel and its interference...

  17. Travel Safety: A Social Media Enabled Mobile Travel Risk Application

    OpenAIRE

    Noyen, Kay; Wortmann, Felix

    2014-01-01

    We present the design artifact Travel Safety, a mobile travel risk information system (IS). Besides offering general travel risk information, the iPhone application leverages social media, in particular Twitter, to source travel risk information from multiple foreign offices. This provides a comprehensive real-time information base for the application and enables dispatch of automatic travel warnings. On the basis of Travel Safety we want to explore if content from social media can be leverag...

  18. NADIM-Travel: A Multiagent Platform for Travel Services Aggregation

    OpenAIRE

    Ben Ameur, Houssein; Bédard, François; Vaucher, Stéphane; Kropf, Peter; Chaib-draaa, Brahim; Gérin-Lajoie, Robert

    2010-01-01

    With the Internet as a growing channel for travel services distribution, sophisticated travel services aggregators are increasingly in demand. A travel services aggregation platform should be able to manage the heterogeneous characteristics of the many existing travel services. It should also be as scalable, robust, and flexible as possible. Using multiagent technology, we designed and implemented a multiagent platform for travel services aggregation called NADIM-Travel. In this platform, a p...

  19. Measured speed versus true speed

    OpenAIRE

    Perez, Israel

    2010-01-01

    The theoretical predictions, derived from the Lorentz and the Tangherlini transformations, for the one-way speed of any physical entity are confronted with the corresponding expressions for the one-way measured speed obtained from a gedanken experiment. The experiment demonstrates that, for an inertial frame $K'$ in motion relative to an inertial frame $K$ where the one-way speed of light is isotropic, even the special theory of relativity renders the one-way speed of light as function of the...

  20. Understanding taxi travel patterns

    Science.gov (United States)

    Cai, Hua; Zhan, Xiaowei; Zhu, Ji; Jia, Xiaoping; Chiu, Anthony S. F.; Xu, Ming

    2016-09-01

    Taxis play important roles in modern urban transportation systems, especially in mega cities. While providing necessary amenities, taxis also significantly contribute to traffic congestion, urban energy consumption, and air pollution. Understanding the travel patterns of taxis is thus important for addressing many urban sustainability challenges. Previous research has primarily focused on examining the statistical properties of passenger trips, which include only taxi trips occupied with passengers. However, unoccupied trips are also important for urban sustainability issues because they represent potential opportunities to improve the efficiency of the transportation system. Therefore, we need to understand the travel patterns of taxis as an integrated system, instead of focusing only on the occupied trips. In this study we examine GPS trajectory data of 11,880 taxis in Beijing, China for a period of three weeks. Our results show that taxi travel patterns share similar traits with travel patterns of individuals but also exhibit differences. Trip displacement distribution of taxi travels is statistically greater than the exponential distribution and smaller than the truncated power-law distribution. The distribution of short trips (less than 30 miles) can be best fitted with power-law while long trips follow exponential decay. We use radius of gyration to characterize individual taxi's travel distance and find that it does not follow a truncated power-law as observed in previous studies. Spatial and temporal regularities exist in taxi travels. However, with increasing spatial coverage, taxi trips can exhibit dual high probability density centers.

  1. Averaging anisotropic cosmologies

    CERN Document Server

    Barrow, J D; Barrow, John D.; Tsagas, Christos G.

    2006-01-01

    We examine the effects of spatial inhomogeneities on irrotational anisotropic cosmologies by looking at the average properties of pressure-free Bianchi-type models. Adopting the Buchert averaging scheme, we identify the kinematic backreaction effects by focussing on spacetimes with zero or isotropic spatial curvature. This allows us to close the system of the standard scalar formulae with a propagation equation for the shear magnitude. We find no change in the already known conditions for accelerated expansion. The backreaction terms are expressed as algebraic relations between the mean-square fluctuations of the models' irreducible kinematical variables. Based on these we investigate the early evolution of averaged vacuum Bianchi type $I$ universes and those filled with pressureless matter. In the latter case we show that the backreaction effects can modify the familiar Kasner-like singularity and potentially remove Mixmaster-type oscillations. We also discuss the possibility of accelerated expansion due to ...

  2. High-Speed RaPToRS

    Science.gov (United States)

    Henchen, Robert; Esham, Benjamin; Becker, William; Pogozelski, Edward; Padalino, Stephen; Sangster, Thomas; Glebov, Vladimir

    2008-11-01

    The High-Speed Rapid Pneumatic Transport of Radioactive Samples (HS-RaPToRS) system, designed to quickly and safely move radioactive materials, was assembled and tested at the Mercury facility of the Naval Research Laboratory (NRL) in Washington D.C. A sample, which is placed inside a four-inch-diameter carrier, is activated before being transported through a PVC tube via airflow. The carrier travels from the reaction chamber to the end station where it pneumatically brakes prior to the gate. A magnetic latch releases the gate when the carrier arrives and comes to rest. The airflow, optical carrier-monitoring devices, and end gate are controlled manually or automatically with LabView software. The installation and testing of the RaPToRS system at NRL was successfully completed with transport times of less than 3 seconds. The speed of the carrier averaged 16 m/s. Prospective facilities for similar systems include the Laboratory for Laser Energetics and the National Ignition Facility.

  3. Nonlinear resonant traveling waves in rotating disks

    Institute of Scientific and Technical Information of China (English)

    AlbertC.J.LUO; ChinAnTAN

    2000-01-01

    The resonant conditions for traveling waves in rotating disks are derived. The nonlinear resonant spectrum of a rotating disk is computed from the resonant conditions.Such a resonant spectrum is useful for the disk drive industry to determine the range of operational rotation speed. The resonant wave motions for linear and nonlinear, rotating disks are simulated numerically for a 3.5-inch diameter computer memory disk.

  4. Average Angular Velocity

    CERN Document Server

    Essén, H

    2003-01-01

    This paper addresses the problem of the separation of rotational and internal motion. It introduces the concept of average angular velocity as the moment of inertia weighted average of particle angular velocities. It extends and elucidates the concept of Jellinek and Li (1989) of separation of the energy of overall rotation in an arbitrary (non-linear) $N$-particle system. It generalizes the so called Koenig's theorem on the two parts of the kinetic energy (center of mass plus internal) to three parts: center of mass, rotational, plus the remaining internal energy relative to an optimally translating and rotating frame.

  5. On sparsity averaging

    CERN Document Server

    Carrillo, Rafael E; Wiaux, Yves

    2013-01-01

    Recent developments in Carrillo et al. (2012) and Carrillo et al. (2013) introduced a novel regularization method for compressive imaging in the context of compressed sensing with coherent redundant dictionaries. The approach relies on the observation that natural images exhibit strong average sparsity over multiple coherent frames. The associated reconstruction algorithm, based on an analysis prior and a reweighted $\\ell_1$ scheme, is dubbed Sparsity Averaging Reweighted Analysis (SARA). We review these advances and extend associated simulations establishing the superiority of SARA to regularization methods based on sparsity in a single frame, for a generic spread spectrum acquisition and for a Fourier acquisition of particular interest in radio astronomy.

  6. Three Generations Travel

    OpenAIRE

    Florya, Yulia

    2014-01-01

    Tourism plays a magnificent role nowadays in people’s life. Now when there are fewer borders and more oppor-tunities to travel, people want to see and explore the world by themselves, together with their families and rela-tives. The thesis focuses on activities for three generation extended family travelers who are staying in Saimaa Holi-day Oravi cottages. The overall purpose is providing real activities for three generation travelers. The objective was to create brand-new activities, to...

  7. Scheduling of high-speed rail traffic based on discrete-time movement model

    International Nuclear Information System (INIS)

    In this paper, a new simulation approach for solving the mixed train scheduling problem on the high-speed double-track rail line is presented. Based on the discrete-time movement model, we propose control strategies for mixed train movement with different speeds on a high-speed double-track rail line, including braking strategy, priority rule, travelling strategy, and departing rule. A new detailed algorithm is also presented based on the proposed control strategies for mixed train movement. Moreover, we analyze the dynamic properties of rail traffic flow on a high-speed rail line. Using our proposed method, we can effectively simulate the mixed train schedule on a rail line. The numerical results demonstrate that an appropriate decrease of the departure interval can enhance the capacity, and a suitable increase of the distance between two adjacent stations can enhance the average speed. Meanwhile, the capacity and the average speed will be increased by appropriately enhancing the ratio of faster train number to slower train number from 1. (general)

  8. Spreading speeds in a lattice differential equation with distributed delay

    OpenAIRE

    Niu, Hui-Ling

    2015-01-01

    This paper studies the spreading speed for a lattice differential equation with infinite distributed delay and we find that the spreading speed coincides with the minimal wave speed of traveling waves. Here the model has been proposed to describe a single species living in a 1D patch environment with infinite number of patches connected locally by diffusion.

  9. On Averaging Rotations

    DEFF Research Database (Denmark)

    Gramkow, Claus

    2001-01-01

    In this paper two common approaches to averaging rotations are compared to a more advanced approach based on a Riemannian metric. Very often the barycenter of the quaternions or matrices that represent the rotations are used as an estimate of the mean. These methods neglect that rotations belong...

  10. Average-passage flow model development

    Science.gov (United States)

    Adamczyk, John J.; Celestina, Mark L.; Beach, Tim A.; Kirtley, Kevin; Barnett, Mark

    1989-01-01

    A 3-D model was developed for simulating multistage turbomachinery flows using supercomputers. This average passage flow model described the time averaged flow field within a typical passage of a bladed wheel within a multistage configuration. To date, a number of inviscid simulations were executed to assess the resolution capabilities of the model. Recently, the viscous terms associated with the average passage model were incorporated into the inviscid computer code along with an algebraic turbulence model. A simulation of a stage-and-one-half, low speed turbine was executed. The results of this simulation, including a comparison with experimental data, is discussed.

  11. Travelers' Health: Leishmaniasis, Visceral

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... such as in northeastern Brazil). In the Old World (Eastern Hemisphere), VL is found in parts of ...

  12. Travelers' Health: Yellow Fever

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... YFV transmission is present,” as defined by the World Health Organization, are countries or areas where “yellow ...

  13. Travelers' Health: Poliomyelitis

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... polio.html ). Country Requirements In May 2014, the World Health Organization (WHO) declared the international spread of ...

  14. Travelers' Health: Hepatitis C

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... surfaces and instruments). In some parts of the world, such as parts of sub-Saharan Africa, blood ...

  15. Travelers' Health: Varicella (Chickenpox)

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... is higher in most other parts of the world than it is in the United States. Varicella ...

  16. Travel Inside the Ear

    Medline Plus

    Full Text Available ... Ear Infections, and Deafness Travel Inside the Ear Video When sound waves reach your ear, you know ... Topics How Do We Hear? What is Sound? Video Have a question? Information specialists can answer your ...

  17. Travelers' Health: Motion Sickness

    Science.gov (United States)

    ... Visiting Friends and Family in Areas with Chikungunya, Dengue, or Zika Travel to the Olympics Infographic: Olympic ... ibandronate sodium, risedronate sodium TREATMENT Nonpharmacologic treatments for preventing and treating motion sickness can be effective with ...

  18. Traveling-wave photodetector

    Science.gov (United States)

    Hietala, Vincent M.; Vawter, Gregory A.

    1993-01-01

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size.

  19. Travelers' Health: HIV Infection

    Science.gov (United States)

    ... or other procedures that pierce the skin, including acupuncture, use of illicit drugs, steroid or vitamin injections, ... contaminated by used needles. Travelers with type 1 diabetes, hemophilia, or other conditions that necessitate routine or ...

  20. Carlson Wagonlit Travel

    CERN Multimedia

    Carlson Wagonlit Travel

    2005-01-01

    Dear customers, On 3 January we informed you that the airlines had decided to cease paying commission to travel agencies in Switzerland. This measure has since been progressively introduced, with rare exceptions. Consequently, in agreement with CERN, we are obliged to apply new transaction fees for private travel, with immediate effect. Carlson Wagonlit Travel (CWT) offers: A personalized, professional and competent consultancy service To seek the most economical and best solution adapted to your needs Neutrality in comparing prices and benefits Additional information concerning e.g. visa regulations, insurance, vaccinations, etc. Support in the event of problems We draw your attention to the fact that, in spite of the increase, these prices remain very competitive on today's market. Thank you for your trust and understanding. Yours truly, Carlson Wagonlit Travel CERN agency

  1. Malaria and Travelers

    Science.gov (United States)

    ... a CDC Malaria Branch clinician. malaria@cdc.gov Malaria and Travelers Recommend on Facebook Tweet Share Compartir ... may be at risk for infection. Determine if malaria transmission occurs at the destinations Obtain a detailed ...

  2. Business travel and sustainability

    OpenAIRE

    Aguilera, Anne

    2013-01-01

    Although it contributes significantly to the demand for transport, in particular air transport, business travel has been relatively neglected in thinking about the strategies needed to promote more sustainable mobility practices. This paper provides a two-stage approach to this subject. We begin by showing how the sustainability of business travel is relevant not only in environmental terms, but also from an economic and social perspective. In the second stage, we consider the strategies that...

  3. Why They Travel Alone?

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    "WHY Chinese Women Travel Alone" was the theme of a special edition of "Truth Talk" a popular talk show on China Central Television (CCTV), which focused on a few middle-aged women from different cultural backgrounds, social classes, and various educational backgrounds who had all branched out on their own for one reason or another. Each woman spoke of her experiences and feelings while travelling alone. They were all

  4. Freedom of Movement (Common Travel Area) (Travel Documentation) Bill 2014

    DEFF Research Database (Denmark)

    Butler, Graham; Hunt, Brian; Flanagan, Terence

    2014-01-01

    Private Members' Bill (legislation) introduced in Dáil Éireann (House of Deputies), Houses of the Oireachtas (Irish Parliament). An Act to reinforce the Common Travel Area by providing for passport-free travel for persons who are entitled to travel within the Common Travel Area without a passport...

  5. The Traveling Microbiome.

    Science.gov (United States)

    Riddle, Mark S; Connor, Bradley A

    2016-09-01

    Given the recent interest in the human gut microbiome in health and disease, we have undertaken a review of the role of the gut microbiome as it relates to travel. Considering the microbiome as the interface with the external world of the traveler, not only from the perspective of protection from enteric infection by colonization resistance but also the possibility that a traveler's unique microbiome may place him or her at lesser or greater risk for enteric infection. We review available data on travel, travelers' diarrhea, and the use of antibiotics as it relates to changes in the microbiome and the acquisition of multi-drug-resistant bacteria and explore the interplay of these factors in the development of dysbiosis and the post-infectious sequelae of TD, specifically PI-IBS. In addition, we explore whether dietary changes in travel affect the gut microbiome in a way which modulates gastrointestinal function and susceptibility to infection and discuss whether pre- or probiotics have any meaningful role in prevention or treatment of TD. Finally, a discussion of important research gaps and opportunities in this area is identified. PMID:27447891

  6. An Exploration - Developing an Online Travel Business

    OpenAIRE

    Gan, Hsia Yen, Gerald

    2009-01-01

    The global travel market is a major industry contributing 9.4% (USD 5,474bn in 2009) to the world’s GDP and employs over 225 million people. Over the last four years the Travel & Tourism industry showed four consecutive years of growth with an average of 3.6% p/a, however growth has slowed down since the second half of 2008, due to the economic climate. The online environment is moving at a rapid pace as entrepreneurs are developing new uses of technology or creating new technology for n...

  7. The averaging principle

    OpenAIRE

    Fibich, Gadi; Gavious, Arieh; Solan, Eilon

    2012-01-01

    Typically, models with a heterogeneous property are considerably harder to analyze than the corresponding homogeneous models, in which the heterogeneous property is replaced with its average value. In this study we show that any outcome of a heterogeneous model that satisfies the two properties of \\emph{differentiability} and \\emph{interchangibility}, is $O(\\epsilon^2)$ equivalent to the outcome of the corresponding homogeneous model, where $\\epsilon$ is the level of heterogeneity. We then us...

  8. Snakes mimic earthworms: propulsion using rectilinear travelling waves

    OpenAIRE

    Marvi, Hamidreza; Bridges, Jacob; Hu, David L.

    2013-01-01

    In rectilinear locomotion, snakes propel themselves using unidirectional travelling waves of muscular contraction, in a style similar to earthworms. In this combined experimental and theoretical study, we film rectilinear locomotion of three species of snakes, including red-tailed boa constrictors, Dumeril's boas and Gaboon vipers. The kinematics of a snake's extension–contraction travelling wave are characterized by wave frequency, amplitude and speed. We find wave frequency increases with i...

  9. Travel probability fields and urban spatial structure: 1. Theory

    OpenAIRE

    M J Beckmann; T F Golob; Zahavi, Y.

    1983-01-01

    The proposed model attempts to explain how particular spatial distributions of trip destinations might arise as manifestations of the accessibility benefits and travel costs associated with a housing location. The trip distributions are elliptical, being expressed as bivariate normal distributions. The parameters of these distributions are shown to be related to the parameters of an assumed density function for activity sites (such as jobs and shops) and to travel speeds. The model implies a ...

  10. On the treatment of airline travelers in mathematical models.

    Directory of Open Access Journals (Sweden)

    Michael A Johansson

    Full Text Available The global spread of infectious diseases is facilitated by the ability of infected humans to travel thousands of miles in short time spans, rapidly transporting pathogens to distant locations. Mathematical models of the actual and potential spread of specific pathogens can assist public health planning in the case of such an event. Models should generally be parsimonious, but must consider all potentially important components of the system to the greatest extent possible. We demonstrate and discuss important assumptions relative to the parameterization and structural treatment of airline travel in mathematical models. Among other findings, we show that the most common structural treatment of travelers leads to underestimation of the speed of spread and that connecting travel is critical to a realistic spread pattern. Models involving travelers can be improved significantly by relatively simple structural changes but also may require further attention to details of parameterization.

  11. Monitoring travel times in an urban network using video, GPS and Bluetooth

    NARCIS (Netherlands)

    Jie, L.; Van Zuylen, H.J.; Chunhua, L.; Shoufeng, L.

    2011-01-01

    The travel time is an important measure for the quality of traffic. This paper discusses a few methods to measure or estimate the travel time in urban road networks. First of all, it is important to know that urban travel times display a large variation, so that the measurement of a single (average)

  12. Knowledge Representation in Travelling Texts

    DEFF Research Database (Denmark)

    Mousten, Birthe; Locmele, Gunta

    2014-01-01

    and the purpose of the text in a new context as well as on predefined parameters for text travel. For texts used in marketing and in technology, the question is whether culture-bound knowledge representation should be domesticated or kept as foreign elements, or should be mirrored or moulded—or should not travel......Today, information travels fast. Texts travel, too. In a corporate context, the question is how to manage which knowledge elements should travel to a new language area or market and in which form? The decision to let knowledge elements travel or not travel highly depends on the limitation...

  13. Faster than light motion does not imply time travel

    International Nuclear Information System (INIS)

    Seeing the many examples in the literature of causality violations based on faster than light (FTL) signals one naturally thinks that FTL motion leads inevitably to the possibility of time travel. We show that this logical inference is invalid by demonstrating a model, based on (3+1)-dimensional Minkowski spacetime, in which FTL motion is permitted (in every direction without any limitation on speed) yet which does not admit time travel. Moreover, the Principle of Relativity is true in this model in the sense that all observers are equivalent. In short, FTL motion does not imply time travel after all. (paper)

  14. On the Origin of Traveling Pulses in Bistable Systems

    CERN Document Server

    Elphick, C; Malomed, B A; Meron, E

    1997-01-01

    The interaction between a pair of Bloch fronts forming a traveling domain in a bistable medium is studied. A parameter range beyond the nonequilibrium Ising-Bloch bifurcation is found where traveling domains collapse. Only beyond a second threshold the repulsive front interactions become strong enough to balance attractive interactions and asymmetries in front speeds, and form stable traveling pulses. The analysis is carried out for the forced complex Ginzburg-Landau equation. Similar qualitative behavior is found in the bistable FitzHugh-Nagumo model.

  15. Speed mathematics

    CERN Document Server

    Handley, Bill

    2012-01-01

    This new, revised edition of the bestselling Speed Mathematics features new chapters on memorising numbers and general information, calculating statistics and compound interest, square roots, logarithms and easy trig calculations. Written so anyone can understand, this book teaches simple strategies that will enable readers to make lightning-quick calculations. People who excel at mathematics use better strategies than the rest of us; they are not necessarily more intelligent. With Speed Mathematics you'll discover methods to make maths easy and fun. This book is perfect for stud

  16. Travel Time Reliability in Indiana

    OpenAIRE

    Martchouk, Maria; Mannering, Fred L.; Singh, Lakhwinder

    2010-01-01

    Travel time and travel time reliability are important performance measures for assessing traffic condition and extent of congestion on a roadway. This study first uses a floating car technique to assess travel time and travel time reliability on a number of Indiana highways. Then the study goes on to describe the use of Bluetooth technology to collect real travel time data on a freeway and applies it to obtain two weeks of data on Interstate 69 in Indianapolis. An autoregressive model, estima...

  17. Negative Average Preference Utilitarianism

    Directory of Open Access Journals (Sweden)

    Roger Chao

    2012-03-01

    Full Text Available For many philosophers working in the area of Population Ethics, it seems that either they have to confront the Repugnant Conclusion (where they are forced to the conclusion of creating massive amounts of lives barely worth living, or they have to confront the Non-Identity Problem (where no one is seemingly harmed as their existence is dependent on the “harmful” event that took place. To them it seems there is no escape, they either have to face one problem or the other. However, there is a way around this, allowing us to escape the Repugnant Conclusion, by using what I will call Negative Average Preference Utilitarianism (NAPU – which though similar to anti-frustrationism, has some important differences in practice. Current “positive” forms of utilitarianism have struggled to deal with the Repugnant Conclusion, as their theory actually entails this conclusion; however, it seems that a form of Negative Average Preference Utilitarianism (NAPU easily escapes this dilemma (it never even arises within it.

  18. Colored Traveling Salesman Problem.

    Science.gov (United States)

    Li, Jun; Zhou, MengChu; Sun, Qirui; Dai, Xianzhong; Yu, Xiaolong

    2015-11-01

    The multiple traveling salesman problem (MTSP) is an important combinatorial optimization problem. It has been widely and successfully applied to the practical cases in which multiple traveling individuals (salesmen) share the common workspace (city set). However, it cannot represent some application problems where multiple traveling individuals not only have their own exclusive tasks but also share a group of tasks with each other. This work proposes a new MTSP called colored traveling salesman problem (CTSP) for handling such cases. Two types of city groups are defined, i.e., each group of exclusive cities of a single color for a salesman to visit and a group of shared cities of multiple colors allowing all salesmen to visit. Evidences show that CTSP is NP-hard and a multidepot MTSP and multiple single traveling salesman problems are its special cases. We present a genetic algorithm (GA) with dual-chromosome coding for CTSP and analyze the corresponding solution space. Then, GA is improved by incorporating greedy, hill-climbing (HC), and simulated annealing (SA) operations to achieve better performance. By experiments, the limitation of the exact solution method is revealed and the performance of the presented GAs is compared. The results suggest that SAGA can achieve the best quality of solutions and HCGA should be the choice making good tradeoff between the solution quality and computing time.

  19. [Travellers to South America].

    Science.gov (United States)

    Lloveras, Susana Cristina

    2011-12-01

    The geography, tourist attractions and the multiple sites of historical and cultural interest make South America as an important destination chosen by travelers. The continent has a wide climatic variation from north to south, making exposure to risk different between the tropics and the temperate or cold regions. In the countries of tropical South America, the greatest risk is associated with the possibility of acquiring vector-borne diseases, like yellow fever, dengue, malaria and leishmaniasis. The risk of acquiring traveler's diarrhea and food-borne illness is similar across the continent, with some variations according to country and to visit urban or rural areas. Rabies, pertussis and diphtheria have appeared as epidemics in several countries and other diseases such as rickettsiosis, hantavirosis and viral encephalitis have expanded their distribution. The geographic and epidemiological diversity of South America, promotes a challenge for travel medicine specialists because during the pre-travel advice they have to take in account the kind of trip, traveller's medical history, exposure to risk and the dynamics of endemic emerging and reemerging diseases in the region.

  20. Razorbill - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  1. Dovekie - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  2. Cloud speed sensor

    Directory of Open Access Journals (Sweden)

    V. Fung

    2013-10-01

    Full Text Available Changing cloud cover is a major source of solar radiation variability and poses challenges for the integration of solar energy. A compact and economical system that measures cloud motion vectors to estimate power plant ramp rates and provide short term solar irradiance forecasts is presented. The Cloud Speed Sensor (CSS is constructed using an array of luminance sensors and high-speed data acquisition to resolve the progression of cloud passages across the sensor footprint. An embedded microcontroller acquires the sensor data and uses a cross-correlation algorithm to determine cloud motion vectors. The CSS was validated against an artificial shading test apparatus, an alternative method of cloud motion detection from ground measured irradiance (Linear Cloud Edge, LCE, and a UC San Diego Sky Imager (USI. The CSS detected artificial shadow directions and speeds to within 15 and 6% accuracy, respectively. The CSS detected (real cloud directions and speeds without average bias and with average weighted root mean square difference of 22° and 1.9 m s−1 when compared to USI and 33° and 1.5 m s−1 when compared to LCE results.

  3. On China's High-Speed Railway Technology

    Institute of Scientific and Technical Information of China (English)

    You-tong FANG

    2011-01-01

    Energy and environmental issues have become increasingly prominent in matters of transportation.Compared with road,air,and sea transportation,railway transportation has the advantages of a large transmission capacity,with rapid,safe,and on-time travel,requiring less land resources,with lower energy consumption,less environmental pollution,and the capacity to operate under most weather conditions.In particular,high-speed railway technology has been growing rapidly.Since the world's first high-speed railway was built in Japan in 1964,more than ten countries and regions have developed high-speed railways,operating over a total of more than 10000 km.High-speed railways not only provide the public with a new type of rapid,convenient,safe,and comfortable travel,but also greatly boost the socio-economic development of the country.

  4. Existence, Uniqueness and Asymptotic Stability of Time Periodic Traveling Waves for a Periodic Lotka-Volterra Competition System with Diffusion.

    Science.gov (United States)

    Zhao, Guangyu; Ruan, Shigui

    2011-06-01

    We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a periodic diffusive Lotka-Volterra competition system. Under certain conditions, we prove that there exists a maximal wave speed c(*) such that for each wave speed c ≤ c(*), there is a time periodic traveling wave connecting two semi-trivial periodic solutions of the corresponding kinetic system. It is shown that such a traveling wave is unique modulo translation and is monotone with respect to its co-moving frame coordinate. We also show that the traveling wave solutions with wave speed c c(*).

  5. [Viral hepatitis in travellers].

    Science.gov (United States)

    Abreu, Cândida

    2007-01-01

    Considering the geographical asymmetric distribution of viral hepatitis A, B and E, having a much higher prevalence in the less developed world, travellers from developed countries are exposed to a considerable and often underestimated risk of hepatitis infection. In fact a significant percentage of viral hepatitis occurring in developed countries is travel related. This results from globalization and increased mobility from tourism, international work, humanitarian and religious missions or other travel related activities. Several studies published in Europe and North America shown that more than 50% of reported cases of hepatitis A are travel related. On the other hand frequent outbreaks of hepatitis A and E in specific geographic areas raise the risk of infection in these restricted zones and that should be clearly identified. Selected aspects related with the distribution of hepatitis A, B and E are reviewed, particularly the situation in Portugal according to the published studies, as well as relevant clinical manifestations and differential diagnosis of viral hepatitis. Basic prevention rules considering enteric transmitted hepatitis (hepatitis A and hepatitis E) and parenteral transmitted (hepatitis B) are reviewed as well as hepatitis A and B immunoprophylaxis. Common clinical situations and daily practice "pre travel" advice issues are discussed according to WHO/CDC recommendations and the Portuguese National Vaccination Program. Implications from near future availability of a hepatitis E vaccine, a currently in phase 2 trial, are highlighted. Potential indications for travellers to endemic countries like India, Nepal and some regions of China, where up to 30% of sporadic cases of acute viral hepatitis are caused by hepatitis E virus, are considered. Continued epidemiological surveillance for viral hepatitis is essential to recognize and control possible outbreaks, but also to identify new viral hepatitis agents that may emerge as important global health

  6. An Optimization Method of Time Window Based on Travel Time and Reliability

    OpenAIRE

    Fengjie Fu; Dongfang Ma; Dianhai Wang; Wei Qian

    2015-01-01

    The dynamic change of urban road travel time was analyzed using video image detector data, and it showed cyclic variation, so the signal cycle length at the upstream intersection was conducted as the basic unit of time window; there was some evidence of bimodality in the actual travel time distributions; therefore, the fitting parameters of the travel time bimodal distribution were estimated using the EM algorithm. Then the weighted average value of the two means was indicated as the travel t...

  7. Malaria prevention in travelers.

    Science.gov (United States)

    Genton, Blaise; D'Acremont, Valérie

    2012-09-01

    A common approach to malaria prevention is to follow the "A, B, C, D" rule: Awareness of risk, Bite avoidance, Compliance with chemoprophylaxis, and prompt Diagnosis in case of fever. The risk of acquiring malaria depends on the length and intensity of exposure; the risk of developing severe disease is primarily determined by the health status of the traveler. These parameters need to be assessed before recommending chemoprophylaxis and/or stand-by emergency treatment. This review discusses the different strategies and drug options available for the prevention of malaria during and post travel.

  8. Time a traveler's guide

    CERN Document Server

    Pickover, Clifford A

    1998-01-01

    ""Bucky Fuller thought big,"" Wired magazine recently noted, ""Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both."" In his newest book, Cliff Pickover outdoes even himself, probing a mystery that has baffled mystics, philosophers, and scientists throughout history--What is the nature of time? In Time: A Traveler's Guide, Pickover takes readers to the forefront of science as he illuminates the most mysterious phenomenon in the universe--time itself. Is time travel possible? Is time real? Does it flow in one direction only? Does it have a beginning and an end? What is eternity? P

  9. WATER TUNNEL EXPERIMENTAL INVESTIGATION ON THE DRAG REDUCTION CHARACTERISTICS OF THE TRAVELING WAVY WALL

    Institute of Scientific and Technical Information of China (English)

    YAO Yan; LU Chuan-jing; SI Ting; ZHU Kun

    2011-01-01

    Drag reduction experiment of the traveling wavy wall at high Reynolds number is conducted. A suit of traveling wavy wall device is developed. The drag forces of the traveling wavy wall with various wave speeds ( c ) are measured under different water speeds (U) in the K15 cavitation water tunnel and are compared with that of the flat plate. The results show that the mean drag force of the traveling wavy wall have decreased and then increased with oscillation frequency increasing at the same flow speed.Under different flow speeds, when traveling wave wall reached to the minimum of drag force, the corresponding the ratio of the wall motion phase speed c to flow speed U, c/U is slightly different. Within the parameters of the experiment, when c/U reaches a certain value, the drag force of the traveling wavy wall can be less than that of the flat plate. The drag reduction can be up to 42%.Furthermore, as the value of c / U increases, the traveling wavy wall can restrain the separation and improve the quality of flow field.

  10. Transferring 2001 National Household Travel Survey

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Patricia S [ORNL; Reuscher, Tim [ORNL; Schmoyer, Richard L [ORNL; Chin, Shih-Miao [ORNL

    2007-05-01

    Policy makers rely on transportation statistics, including data on personal travel behavior, to formulate strategic transportation policies, and to improve the safety and efficiency of the U.S. transportation system. Data on personal travel trends are needed to examine the reliability, efficiency, capacity, and flexibility of the Nation's transportation system to meet current demands and to accommodate future demand. These data are also needed to assess the feasibility and efficiency of alternative congestion-mitigating technologies (e.g., high-speed rail, magnetically levitated trains, and intelligent vehicle and highway systems); to evaluate the merits of alternative transportation investment programs; and to assess the energy-use and air-quality impacts of various policies. To address these data needs, the U.S. Department of Transportation (USDOT) initiated an effort in 1969 to collect detailed data on personal travel. The 1969 survey was the first Nationwide Personal Transportation Survey (NPTS). The survey was conducted again in 1977, 1983, 1990, 1995, and 2001. Data on daily travel were collected in 1969, 1977, 1983, 1990 and 1995. In 2001, the survey was renamed the National Household Travel Survey (NHTS) and it collected both daily and long-distance trips. The 2001 survey was sponsored by three USDOT agencies: Federal Highway Administration (FHWA), Bureau of Transportation Statistics (BTS), and National Highway Traffic Safety Administration (NHTSA). The primary objective of the survey was to collect trip-based data on the nature and characteristics of personal travel so that the relationships between the characteristics of personal travel and the demographics of the traveler can be established. Commercial and institutional travel were not part of the survey. Due to the survey's design, data in the NHTS survey series were not recommended for estimating travel statistics for categories smaller than the combination of Census division (e.g., New

  11. Travel, speed and entertainment in cinema territories and aviation

    Directory of Open Access Journals (Sweden)

    João Luís Jesus Fernandes

    2016-02-01

    Full Text Available Book review and critical reading of a book that crosses cinema and the aviation transport, a work that understands the latter as a territory of cinema diffusion. The films shown in the aircraft are designed to entertain the passengers, keep them calm, but also to promote marketing campaigns and lifestyles.

  12. Existence, Uniqueness and Asymptotic Stability of Time Periodic Traveling Waves for a Periodic Lotka-Volterra Competition System with Diffusion

    OpenAIRE

    Zhao, Guangyu; Ruan, Shigui

    2011-01-01

    We study the existence, uniqueness, and asymptotic stability of time periodic traveling wave solutions to a periodic diffusive Lotka-Volterra competition system. Under certain conditions, we prove that there exists a maximal wave speed c* such that for each wave speed c ≤ c*, there is a time periodic traveling wave connecting two semi-trivial periodic solutions of the corresponding kinetic system. It is shown that such a traveling wave is unique modulo translation and is monotone with respect...

  13. Beijing Time Travel

    Institute of Scientific and Technical Information of China (English)

    ROBERT; T.TUOHEY

    2010-01-01

    Daily travel within Beijing need not be anymore troublesome than going about any major metropolis.Simply,certain basic facts need to be kept in mind,and ordinary precautions taken.Essentially,it’s the same situation as midtown Manhattan or downtown Tokyo,except everyone’s speaking Chinese.

  14. Beijing Time Travel

    Institute of Scientific and Technical Information of China (English)

    ROBERT T.TUOHEY

    2010-01-01

    @@ Dally travel within Beijing need not be anymore troublesome than going about any major metropolis.Simply,certain basic facts need to be kept in mind,and ordinary precautions taken.Essentially,it's the same situation as midtown Manhattan or downtown Tokyo,except everyone's speaking Chinese.

  15. Flu and Holiday Travel

    Centers for Disease Control (CDC) Podcasts

    2010-12-13

    This podcast explains the ways people can stay healthy and avoid the flu when traveling this winter.  Created: 12/13/2010 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 12/13/2010.

  16. Travel Inside the Ear

    Medline Plus

    Full Text Available ... Search form Search A–Z Index Español Menu Home Health Info Hearing, Ear Infections, and Deafness Balance ... Committees Contact Us Get Involved You are here Home » Health Info » Hearing, Ear Infections, and Deafness Travel ...

  17. Travel Inside the Ear

    Medline Plus

    Full Text Available ... Deafness Travel Inside the Ear Video When sound waves reach your ear, you know you've heard ... the sound through the hair cells to your brain. Last Updated Date: July 30, 2014 Languages Español ...

  18. Travelers' Health: Hepatitis B

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... developing world and transmission of bloodborne pathogens: a review. Bull World Health Organ. 1999;77(10):789–800. Chapter 3 - ...

  19. A new method for shear wave speed estimation in shear wave elastography.

    Science.gov (United States)

    Engel, Aaron J; Bashford, Gregory R

    2015-12-01

    Visualization of mechanical properties of tissue can aid in noninvasive pathology diagnosis. Shear wave elastography (SWE) measures the elastic properties of soft tissues by estimation of local shear wave propagation speed. In this paper, a new robust method for estimation of shear wave speed is introduced which has the potential for simplifying continuous filtering and real-time elasticity processing. Shear waves were generated by external mechanical excitation and imaged at a high frame rate. Three homogeneous phantoms of varying elastic moduli and one inclusion phantom were imaged. Waves propagating in separate directions were filtered and shear wave speed was estimated by inversion of the 1-D first-order wave equation. Final 2-D shear wave speed maps were constructed by weighted averaging of estimates from opposite traveling directions. Shear wave speed results for phantoms with gelatin concentrations of 5%, 7%, and 9% were 1.52 ± 0.10 m/s, 1.86 ± 0.10 m/s, and 2.37 ± 0.15 m/s, respectively, which were consistent with estimates computed from three other conventional methods, as well as compression tests done with a commercial texture analyzer. The method was shown to be able to reconstruct a 2-D speed map of an inclusion phantom with good image quality and variance comparable to conventional methods. Suggestions for further work are given. PMID:26670851

  20. Unconscious local motion alters global image speed.

    Directory of Open Access Journals (Sweden)

    Sieu K Khuu

    Full Text Available Accurate motion perception of self and object speed is crucial for successful interaction in the world. The context in which we make such speed judgments has a profound effect on their accuracy. Misperceptions of motion speed caused by the context can have drastic consequences in real world situations, but they also reveal much about the underlying mechanisms of motion perception. Here we show that motion signals suppressed from awareness can warp simultaneous conscious speed perception. In Experiment 1, we measured global speed discrimination thresholds using an annulus of 8 local Gabor elements. We show that physically removing local elements from the array attenuated global speed discrimination. However, removing awareness of the local elements only had a small effect on speed discrimination. That is, unconscious local motion elements contributed to global conscious speed perception. In Experiment 2 we measured the global speed of the moving Gabor patterns, when half the elements moved at different speeds. We show that global speed averaging occurred regardless of whether local elements were removed from awareness, such that the speed of invisible elements continued to be averaged together with the visible elements to determine the global speed. These data suggest that contextual motion signals outside of awareness can both boost and affect our experience of motion speed, and suggest that such pooling of motion signals occurs before the conscious extraction of the surround motion speed.

  1. The Tourist Itinerary Travel Loop: historical and contemporary travel characteristics

    OpenAIRE

    Lundgren, Jan O.

    2012-01-01

    In today’s tourist travel, the travel loop represents a very popular itinerary design, although the circumstances under which it is applied, as well as its geographic scale, often differ from the grandiose loop designs of centuries past. During the past couple of decades, a popular kind of new travel has emerged, the cruise-ship travel phenomenon, which often is arranged as quite an extensive itinerary loop. . However, the cruises can also be transoceanic, even global, with the tourist flying...

  2. Valuation of Travel Time and TravelIer Information

    OpenAIRE

    Rietveld, Piet

    2003-01-01

    The value of travel time plays an important role in cost benefit analysis of infrastructureprojects. However, the issue of uncertainty on travel times and the implications this has forestimations of travel time values has received much less attention in the literature. In thispaper we compare various modelling approaches to address uncertainty and demonstrate thatignoring uncertainty issues may easily lead to distorted estimates of values of travel time. Thisis of special relevance in public ...

  3. Do British travel agents provide adequate health advice for travellers?

    OpenAIRE

    Lawlor, D A; J. Burke; Bouskill, E; Conn, G; Edwards, P.; Gillespie, D.

    2000-01-01

    Travel-related illness is a burden for primary care, with more than two million travellers consulting a general practitioner each year. The annual cost of travel-related illness in the United Kingdom is 11 million Pounds. Travel agents are in a unique position to influence this burden as the most common and most serious problems are preventable with simple advice and/or immunisation. This study, using covert researchers, suggests this potential is not being fully utilised.

  4. Testing the Effect of Hydrophilic and Hydrophobic Coatings on the Speed of a Ball through Water

    CERN Document Server

    Wiegand, Natalie

    2013-01-01

    Data is presented that confirms that hydrophobic coatings reduce friction between objects and water. The results show that the average time it took for the ball with the hydrophobic coating traveled at an average of about 6 inches per second. The ball with the hydrophilic coating traveled at a slower pace, moving at an average of about 5 inches per second and the ball without a coating traveled at an average of about 4.8 inches per second.

  5. Valuation of Travel Time and TravelIer Information

    NARCIS (Netherlands)

    Rietveld, Piet

    2003-01-01

    The value of travel time plays an important role in cost benefit analysis of infrastructureprojects. However, the issue of uncertainty on travel times and the implications this has forestimations of travel time values has received much less attention in the literature. In thispaper we compare variou

  6. Evaluating School Travel Initiatives and Promoting "Healthy Travel" through PSHCE

    Science.gov (United States)

    Baslington, Hazel

    2010-01-01

    The number of primary school children travelling to school by car in the UK has almost doubled from 22% to 43% in 20 years. A governmental policy response is school travel plans (STPs). This paper reports the findings of an empirical evaluation designed to measure the effectiveness of the travel initiative at three schools. Quantitative and…

  7. Asymptotic speed of spreading in a delay lattice differential equation without quasimonotonicity

    OpenAIRE

    Fuzhen Wu

    2014-01-01

    This article concerns the asymptotic speed of spreading in a delay lattice differential equation without quasimonotonicity. We obtain the speed of spreading by constructing an auxiliary undelayed equation, whose speed of spreading is the same as that of the original equation. The minimal wave speed of bounded positive traveling wave solutions is obtained from the asymptotic spreading.

  8. The stiffness variation of a micro-ring driven by a traveling piecewise-electrode.

    Science.gov (United States)

    Li, Yingjie; Yu, Tao; Hu, Yuh-Chung

    2014-01-01

    In the practice of electrostatically actuated micro devices; the electrostatic force is implemented by sequentially actuated piecewise-electrodes which result in a traveling distributed electrostatic force. However; such force was modeled as a traveling concentrated electrostatic force in literatures. This article; for the first time; presents an analytical study on the stiffness variation of microstructures driven by a traveling piecewise electrode. The analytical model is based on the theory of shallow shell and uniform electrical field. The traveling electrode not only applies electrostatic force on the circular-ring but also alters its dynamical characteristics via the negative electrostatic stiffness. It is known that; when a structure is subjected to a traveling constant force; its natural mode will be resonated as the traveling speed approaches certain critical speeds; and each natural mode refers to exactly one critical speed. However; for the case of a traveling electrostatic force; the number of critical speeds is more than that of the natural modes. This is due to the fact that the traveling electrostatic force makes the resonant frequencies of the forward and backward traveling waves of the circular-ring different. Furthermore; the resonance and stability can be independently controlled by the length of the traveling electrode; though the driving voltage and traveling speed of the electrostatic force alter the dynamics and stabilities of microstructures. This paper extends the fundamental insights into the electromechanical behavior of microstructures driven by electrostatic forces as well as the future development of MEMS/NEMS devices with electrostatic actuation and sensing. PMID:25230308

  9. The Stiffness Variation of a Micro-Ring Driven by a Traveling Piecewise-Electrode

    Directory of Open Access Journals (Sweden)

    Yingjie Li

    2014-09-01

    Full Text Available In the practice of electrostatically actuated micro devices; the electrostatic force is implemented by sequentially actuated piecewise-electrodes which result in a traveling distributed electrostatic force. However; such force was modeled as a traveling concentrated electrostatic force in literatures. This article; for the first time; presents an analytical study on the stiffness variation of microstructures driven by a traveling piecewise electrode. The analytical model is based on the theory of shallow shell and uniform electrical field. The traveling electrode not only applies electrostatic force on the circular-ring but also alters its dynamical characteristics via the negative electrostatic stiffness. It is known that; when a structure is subjected to a traveling constant force; its natural mode will be resonated as the traveling speed approaches certain critical speeds; and each natural mode refers to exactly one critical speed. However; for the case of a traveling electrostatic force; the number of critical speeds is more than that of the natural modes. This is due to the fact that the traveling electrostatic force makes the resonant frequencies of the forward and backward traveling waves of the circular-ring different. Furthermore; the resonance and stability can be independently controlled by the length of the traveling electrode; though the driving voltage and traveling speed of the electrostatic force alter the dynamics and stabilities of microstructures. This paper extends the fundamental insights into the electromechanical behavior of microstructures driven by electrostatic forces as well as the future development of MEMS/NEMS devices with electrostatic actuation and sensing.

  10. Travel opinion leaders and seekers

    DEFF Research Database (Denmark)

    Yoo, Kyung-Hyan; Gretzel, Ulrike; Zach, Florian

    2011-01-01

    While opinion leadership has been recognized as important in tourism, there has been very little empirical research investigating the phenomenon. Given new developments in social media technologies, it is especially important to understand whether travel opinion leadership and seeking are drivers...... of specific social media perceptions and behaviours. Based on an online survey of US online travellers, this paper seeks to identify travel opinion leaders and seekers and their characteristics. Further, the research conducted investigated linkages between travel opinion leadership/seeking and travel social...... media use. The findings suggest that travel opinion leadership and seeking are distinct but connected. Both opinion leaders and seekers are technology savvy, young, educated, involved in travel planning and engaged in social media use for travel. What distinguishes opinion leaders is their greater...

  11. Travelers' Health: Injuries and Safety

    Science.gov (United States)

    ... Visiting Friends and Family in Areas with Chikungunya, Dengue, or Zika Travel to the Olympics Infographic: Olympic ... 297–307. Sleet DA, Balaban V. Travel medicine: preventing injuries to children. Am J Lifestyle Med. 2013 ...

  12. The effect of travel restrictions on the spread of a highly contagious disease in Sweden

    OpenAIRE

    Camitz, Martin; Liljeros, Fredrik

    2005-01-01

    Travel restrictions may reduce the spread of a contagious disease that threatens public health. In this study we investigate what effect different levels of travel restrictions may have on the speed and geographical spread of an outbreak of a disease similar to SARS. We use a stochastic simulation model of the Swedish population, calibrated with survey data of travel patterns between municipalities in Sweden collected over three years. We find that a ban on journeys longer than 50 km drastica...

  13. Travel and Adventure Medicine Resources.

    Science.gov (United States)

    Sanford, Christopher A; Pottinger, Paul S

    2016-03-01

    Given the ever-changing nature of travel medicine, practitioners who provide pretravel and posttravel care are obligatorily students for the duration of their professional careers. A large variety of resources are available for medical practitioners. Providers should join at least one travel or tropical medicine professional association, attend its annual meeting, and read its journal. The largest general travel medicine association is the International Society of Travel Medicine.

  14. Evidence on global medical travel

    OpenAIRE

    Ruggeri, Kai; Záliš, Ladislav; Meurice, Christopher R; Hilton, Ian; Ly, Terry-Lisa; Zupan, Zorana; Hinrichs, Saba

    2015-01-01

    Abstract The potential benefits of travelling across national borders to obtain medical treatment include improved care, decreased costs and reduced waiting times. However, medical travel involves additional risks, compared to obtaining treatment domestically. We review the publicly-available evidence on medical travel. We suggest that medical travel needs to be understood in terms of its potential risks and benefits so that it can be evaluated against alternatives by patients who are seeking...

  15. Travel and Adventure Medicine Resources.

    Science.gov (United States)

    Sanford, Christopher A; Pottinger, Paul S

    2016-03-01

    Given the ever-changing nature of travel medicine, practitioners who provide pretravel and posttravel care are obligatorily students for the duration of their professional careers. A large variety of resources are available for medical practitioners. Providers should join at least one travel or tropical medicine professional association, attend its annual meeting, and read its journal. The largest general travel medicine association is the International Society of Travel Medicine. PMID:26900122

  16. Lattice Boltzmann simulation of transverse wave travelling in Maxwell viscoelastic fluid

    Institute of Scientific and Technical Information of China (English)

    Li Hua-Bing; Fang Hai-Ping

    2004-01-01

    A nine-velocity lattice Boltzmann method for Maxwell viscoelastic fluid is proposed. Travelling of transverse wave in Maxwell viscoelastic fluid is simulated. The instantaneous oscillating velocity, transverse shear speed and decay rate agree with theoretical results very well.

  17. Dissociating Averageness and Attractiveness: Attractive Faces Are Not Always Average

    Science.gov (United States)

    DeBruine, Lisa M.; Jones, Benedict C.; Unger, Layla; Little, Anthony C.; Feinberg, David R.

    2007-01-01

    Although the averageness hypothesis of facial attractiveness proposes that the attractiveness of faces is mostly a consequence of their averageness, 1 study has shown that caricaturing highly attractive faces makes them mathematically less average but more attractive. Here the authors systematically test the averageness hypothesis in 5 experiments…

  18. Remote sensing of temperature and wind using acoustic travel-time measurements

    Directory of Open Access Journals (Sweden)

    Manuela Barth

    2013-04-01

    Full Text Available A remote sensing technique to detect area-averaged temperature and flow properties within an area under investigation, utilizing acoustic travel-time measurements, is introduced. This technique uses the dependency of the speed of acoustic signals on the meteorological parameters temperature and wind along the propagation path. The method itself is scalable: It is applicable for investigation areas with an extent of some hundred square metres as well as for small-scale areas in the range of one square metre. Moreover, an arrangement of the acoustic transducers at several height levels makes it possible to determine profiles and gradients of the meteorological quantities. With the help of two examples the potential of this remote sensing technique for simultaneously measuring averaged temperature and flow fields is demonstrated. A comparison of time histories of temperature and wind values derived from acoustic travel-time measurements with point measurements shows a qualitative agreement whereas calculated root-mean-square errors differ for the two example applications. They amount to 1.4 K and 0.3 m/s for transducer distances of 60 m and 0.4 K and 0.2 m/s for transducer distances in the range of one metre.

  19. [The fever of international travel].

    Science.gov (United States)

    Hristea, Adriana; Luka, A I; Aramă, Victoria; Moroti, Ruxandra

    2008-01-01

    Between 20 and 70 percent of the 50 million people who travel from the industrialized world to the developing world each year report some illness associated with their travel. Although most illness reported by travellers are mild, 20-70% of travellers become ill enough to seek medical attention, either during or immediately after travel. The full spectrum of health complaints is unknown. Nevertheless the usual presentation of a returned traveller is a particular syndrome-fever, respiratory infection, diarrhoea, eosinophilia, or skin and soft tissue infection- or screening for asymptomatic infection. The most common diseases diagnosed in returning travellers are more often of cosmopolitan than exotic origin. However, fever in returned travelers always should raise suspicion for a severe or potentially life-threatening tropical infection. Therefore, fever in a returned traveller requires prompt investigation focused on infections that are life-threatening, treatable or transmissible. Careful assessment of the travel history, likely incubation period, exposure history, associated signs and symptoms, duration of fever, immunization status, use or non-use of antimalarial chemoprophylaxis and degree of compliance with the prescribed regimen, if used, helps to establish the diagnosis. Determining an approximate incubation period can be particularly helpful in ruling out possible causes of fever. Malaria is the most important cause of fever in the returned traveller. While most travel-related infections present within 6 months of return, some infections with long latent periods or potential for lifetime persistence might be seen in those who have lived abroad. PMID:20201239

  20. Trends in commuter and leisure travel in The Netherlands 1991-2001 - Mode choice and travel time

    OpenAIRE

    Collins, Christy; de Blaeij, Arianne

    2005-01-01

    Data collected over recent years indicates that there has been an increase in the average distance of trips made, in the Netherlands (e.g. in 1985 the average trip made was 8.7 km, in 2000 the average trip length was 10.6 km (Harms, 2003)). This paper uses a multi-level approach to look at the micro and macro level factors that affect the travel behaviour of individuals for commuting and leisure in the Netherlands over the last 10 years. A strong influence on the travel behaviour of an indivi...

  1. Lower bounds for non-trivial travelling wave solutions of equations of KdV type

    International Nuclear Information System (INIS)

    We prove that if a solution of an equation of KdV type is bounded above by a travelling wave with an amplitude that decays faster than a given linear exponential then it must be zero. We assume no restrictions neither on the size nor in the direction of the speed of the travelling wave

  2. Existence of travelling wave solutions for a Fisher-Kolmogorov system with biomedical applications

    Science.gov (United States)

    Belmonte-Beitia, Juan

    2016-07-01

    We consider a Fisher-Kolmogorov system with applications in oncology Pérez-García et al. (2015). Of interest is the question of the existence of travelling front solutions of the system. When the speed of the travelling wave is sufficiently large, existence of such fronts is shown using singular geometric perturbation theory.

  3. Travel time impacts analysis of system-wide signal timing optimization methodology

    OpenAIRE

    Ainchil Cayuela, Luis María

    2014-01-01

    This study analyzes the economic impact that users would experience with the travel time variation due to system-wide signal timing optimization. To do this, a comprehensive analysis of travel time user benefits is conducted using traffic volume, speed and other attributes of road network, before and after signal timing optimization.

  4. Valuation of travel time for international long-distance travel - results from the Fehmarn Belt stated choice experiment

    DEFF Research Database (Denmark)

    Mabit, Stefan Lindhard; Rich, Jeppe; Burge, Peter;

    2013-01-01

    significant interactions among travel cost and time, and journey characteristics, such as distance and duration. This had direct impact on the VTTS, which was shown to decrease with distance and duration. Thirdly, we found that air travel implies a higher average VTTS, which is to be expected but rarely...... on the Fehmarn Belt fixed link between Germany and Denmark to be opened in 2021. To facilitate long-term demand forecasts for the future fixed link, stated preference data were collected in 2011. Based on these data a discrete choice model for long-distance travellers was developed in order to estimate the value...... of travel time savings (VTTS). The final model, which was formulated as a nested logit model and included Box–Cox transformed travel time and cost attributes, revealed several interesting findings. Firstly, we found damping effects in both cost and time – most strongly in cost. Secondly, we found...

  5. The Effect of Speed Camera Warning Sign on Vehicle Speed in School Zones

    Directory of Open Access Journals (Sweden)

    M.M. Rohani

    2014-12-01

    Full Text Available Driving too fast is one of the most prevalent factors that contribute to traffic crashes. In school zones, staying alert and obeying the posted speed limit especially during the school period are imperative for public safety, particularly involving children. Encouraging motorists to travel at safe speeds through the installation of yellow transverse bars at Seri Sabak Uni School and Pintas Puding School was found to be ineffective. Drivers were observed to have violated the 30 km/h speed limit and more seriously, driven over the speed limits of adjoining roads. Consequently, speed camera warning signs were erected as a pre-emptive measure to curtail speeding problems in the school zones. From impact studies carried out to measure the effectiveness of these signs, it was found that the speed camera warning signs were also not able to change driver behavior.

  6. The need for speed: global optic flow speed influences steering.

    Science.gov (United States)

    Kountouriotis, Georgios K; Mole, Callum D; Merat, Natasha; Wilkie, Richard M

    2016-05-01

    How do animals follow demarcated paths? Different species are sensitive to optic flow and one control solution is to maintain the balance of flow symmetry across visual fields; however, it is unclear whether animals are sensitive to changes in asymmetries when steering along curved paths. Flow asymmetries can alter the global properties of flow (i.e. flow speed) which may also influence steering control. We tested humans steering curved paths in a virtual environment. The scene was manipulated so that the ground plane to either side of the demarcated path produced larger or smaller asymmetries in optic flow. Independent of asymmetries and the locomotor speed, the scene properties were altered to produce either faster or slower globally averaged flow speeds. Results showed that rather than being influenced by changes in flow asymmetry, steering responded to global flow speed. We conclude that the human brain performs global averaging of flow speed from across the scene and uses this signal as an input for steering control. This finding is surprising since the demarcated path provided sufficient information to steer, whereas global flow speed (by itself) did not. To explain these findings, existing models of steering must be modified to include a new perceptual variable: namely global optic flow speed. PMID:27293789

  7. CARLSON WAGONLIT TRAVEL

    CERN Multimedia

    CARLSON WAGONLIT TRAVEL

    2004-01-01

    CARLSON WAGONLIT TRAVEL would like to remind you of the entry formalities applicable to those travelling to the United States. Nationals of Switzerland and of the following countries : Andorra, Australia, Austria, Belgium, Brunei, Denmark, Finland, France, Germany, Iceland, Ireland, Italy, Japan, Liechtenstein, Luxemburg, Monaco, Netherlands, New Zealand, Norway, Portugal, San Marino, Singapore, Slovenia, Spain, Sweden and the United Kingdom, entering the United States under the Visa Waiver Program (no visa requirement), must be in possession of an machine-readable passport that is valid for at least six months after the date of the return trip. Children, including infants, must have their own passport. An entry in the parents' passport is not sufficient. For entry into the United States, an e-ticket (fax or e-mail confirmation or passenger receipt) or a return ticket to the departure point or a ticket to a subsequent onward destination (valid for 90 days) must be presented together with the green ...

  8. Last Passage Percolation and Traveling Waves

    CERN Document Server

    Comets, Francis; Ramirez, Alejandro F

    2012-01-01

    We consider a system of N particles with a stochastic dynamics introduced by Brunet and Derrida. The particles can be interpreted as last passage times in directed percolation on {1,...,N} of mean-field type. The particles remain grouped and move like a traveling wave, subject to discretization and driven by a random noise. As N increases, we obtain estimates for the speed of the front and its profile, for different laws of the driving noise. The Gumbel distribution plays a central role for the particle jumps, and we show that the scaling limit is a L \\'evy process in this case. The case of bounded jumps yields a completely different behavior.

  9. Hybrid Modelling of a Traveling Wave Piezoelectric Motor

    DEFF Research Database (Denmark)

    El, Ghouti N.

    of an ultrasonic traveling wave rotary piezoelectric motor. This approach is carried out on the basis of the experimental investigation combined with the electrical network method. Consequently, an insight in the analysis of the electromechanical coupling force factor, which is responsible for the electrical......This thesis considers the modeling of the traveling wave piezoelectric motor (PEM). The rotary traveling wave ultrasonic motor "Shinsei type USR60" is the case study considered in this work. The traveling wave PEM has excellent performance and many useful features such as high holding torque, high...... torque at low speed, quiet operation (ultrasonic), simple structure, compactness in size and no electromagnetic interferences. However, the mathematical model of the PEM is complex and difficult to derive due to its driving principle based on high-frequency mechanical vibrations and frictional force...

  10. Leisure and Travel Choice

    OpenAIRE

    María José Caride; Eduardo L. Giménez

    2003-01-01

    It is commonly recognized the relevance of transportation costs for studying recre- ational demand. However, these costs are related with travel and modal choice deci- sions. This paper o ers a theoretical explanation of the new generation of the demand for recreational goods at destiny after the introduction of a new transportation mode that is not the cheapest nor the fastest among the available modes. The main feature of the model deals with the transportation mode-dependent preferences. T...

  11. Malaria and Tropical Travel

    Centers for Disease Control (CDC) Podcasts

    2008-05-15

    Malaria is a serious mosquito-borne disease that can lead to death. This podcast discusses malaria risk when traveling to tropical areas, as well as how to protect yourself and your family from malaria infection.  Created: 5/15/2008 by National Center for Zoonotic, Vector-Borne, and Enteric Diseases (NCZVED).   Date Released: 5/29/2008.

  12. Active Travel Behavior

    OpenAIRE

    Burbidge, Shaunna K; Goulias, Konstadinos G.

    2008-01-01

    Physical inactivity has become a dominant feature of most American’s lives over the past quarter century. This has spurred an entire research domain straddling several different disciplines. Although model development within the field of travel behavior as a whole continues today with more momentum than ever, the focus on active mode choice has largely been overlooked and left to a small fragment of transportation and public health researchers. Research regarding active mode choice has been...

  13. Aging and space travel

    Science.gov (United States)

    Mohler, S. R.

    1982-01-01

    The matter of aging and its relation to space vehicle crewmembers undertaking prolonged space missions is addressed. The capabilities of the older space traveler to recover from bone demineralization and muscle atrophy are discussed. Certain advantages of the older person are noted, for example, a greater tolerance of monotony and repetitious activities. Additional parameters are delineated including the cardiovascular system, the reproductive system, ionizing radiation, performance, and group dynamics.

  14. Diversity does not travel!

    DEFF Research Database (Denmark)

    Lund, Rebecca; Meriläinen, Susan; Tienari, Janne

    2014-01-01

    In this chapter we offer insights into the social construction of diversity in Finnish organizations and society. In Finnish organizations, gender is highlighted while other markers of diversity are blotted out. 'Non-Finns' become subject to cultural assimilation. The US-based concept of Diversity...... Management becomes adopted and adapted in particular ways. Standardized concepts of diversity and its management do not travel, rather they become translated locally. In organizational practice, globalization is slow and laborious....

  15. Time - A Traveler's Guide

    Science.gov (United States)

    Pickover, Clifford A.

    1999-09-01

    "Bucky Fuller thought big," Wired magazine recently noted, "Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." In his newest book, Cliff Pickover outdoes even himself, probing a mystery that has baffled mystics, philosophers, and scientists throughout history--What is the nature of time?In Time: A Traveler's Guide , Pickover takes readers to the forefront of science as he illuminates the most mysterious phenomenon in the universe--time itself. Is time travel possible? Is time real? Does it flow in one direction only? Does it have a beginning and an end? What is eternity? Pickover's book offers a stimulating blend of Chopin, philosophy, Einstein, and modern physics, spiced with diverting side-trips to such topics as the history of clocks, the nature of free will, and the reason gold glitters. Numerous diagrams ensure readers will have no trouble following along.By the time we finish this book, we understand a wide variety of scientific concepts pertaining to time. And most important, we will understand that time travel is, indeed, possible.

  16. When CERN travels abroad

    CERN Multimedia

    CERN Bulletin

    2010-01-01

    For the first time the new CERN travelling exhibition has gone abroad. The venue is Torino, in Italy, where it is being shown at the Museum of Natural Science in the framework of the activities of the EuroScience Open Forum (ESOF 2010). Soon after the event, the exhibition will fly to Copenhagen. The CERN traveling exhibition was inaugurated in 2009. The new ‘Accelerating Science’ exhibition was inaugurated in 2009 as part of the celebrations to mark the 450th anniversary of the University of Geneva. “CERN’s travelling exhibition is an important tool for outreach in our Member states as it carries the main messages that constitute the backbone of the Laboratory’s education and communication policy”, explains Rolf Landua, head of the Education Group, which manages the exhibition. “The 2010 European Science Open Forum in Torino will gather a lot of experts and visitors from the general public who will be able to experience in an ...

  17. Carlson Wagonlit Travel

    CERN Multimedia

    2006-01-01

    Carlson Wagonlit Travel wishes to remind you of the following conditions concerning travel to the USA. Passport conditions Since 26 October 2004, nationals of the countries covered by the US Visa Waiver Programme have been required to present a valid machine-readable passport when entering the United States. Failing this, they require a valid US non-immigrant visa in addition to their passport. Passports issued after 25 October 2005 must also bear a digital photograph. Passports issued after 25 October 2006 must contain biometric data to allow visa-free entry to the US. Advanced Passenger Information System (APIS) form Since 4 October 2005, all non-US citizens travelling to the USA have been required to complete the APIS form before departure and present it when they check in. This new procedure will certainly increase the time it takes to check in. We therefore advise passengers to present themselves at the respective check-in desk in good time. The APIS form can be downloaded from our homepage: w...

  18. Virtual Averaging Making Nonframe-Averaged Optical Coherence Tomography Images Comparable to Frame-Averaged Images

    OpenAIRE

    Chen, Chieh-Li; Ishikawa, Hiroshi; Wollstein, Gadi; Bilonick, Richard A.; Kagemann, Larry; Schuman, Joel S.

    2016-01-01

    Purpose Developing a novel image enhancement method so that nonframe-averaged optical coherence tomography (OCT) images become comparable to active eye-tracking frame-averaged OCT images. Methods Twenty-one eyes of 21 healthy volunteers were scanned with noneye-tracking nonframe-averaged OCT device and active eye-tracking frame-averaged OCT device. Virtual averaging was applied to nonframe-averaged images with voxel resampling and adding amplitude deviation with 15-time repetitions. Signal-to...

  19. The Use of Communication Technologies in Road Travel Agencies

    Directory of Open Access Journals (Sweden)

    Tüba KARAHİSAR

    2012-05-01

    Full Text Available With the communication technologies moving into our lives any longer, load travel agencies have begun to improve their services accordingly. They are constantly seeking new services to make road travel more fun. Now, during a travel by road travel vehicles, it is possible to transfer road view, travel duration and speed limit information with a camera in front of the car; and to play computer games, watch digital and interactive channels, connect internet, listen to music, access current news and have information on places on the drive with screens placed behind the seats. Thus, in this study, communication technologies used in the load travel agencies of Turkey have been analyzed. To this end, websites of 159 travel agencies that are registered to Istanbul Bus Terminal have been searched. It has been found that 80 of these 159 agencies have one website. The relevant agencies have been reached via mail or phone, and a survey has been implemented on their public relations authorities.

  20. Evidence on global medical travel.

    Science.gov (United States)

    Ruggeri, Kai; Záliš, Ladislav; Meurice, Christopher R; Hilton, Ian; Ly, Terry-Lisa; Zupan, Zorana; Hinrichs, Saba

    2015-11-01

    The potential benefits of travelling across national borders to obtain medical treatment include improved care, decreased costs and reduced waiting times. However, medical travel involves additional risks, compared to obtaining treatment domestically. We review the publicly-available evidence on medical travel. We suggest that medical travel needs to be understood in terms of its potential risks and benefits so that it can be evaluated against alternatives by patients who are seeking care. We propose three domains -quality standards, informed decision-making, economic and legal protection - in which better evidence could support the development of medical travel policies. PMID:26549906

  1. Superluminal travel requires negative energies

    OpenAIRE

    Olum, Ken D.

    1998-01-01

    I investigate the relationship between faster-than-light travel and weak-energy-condition violation, i.e., negative energy densities. In a general spacetime it is difficult to define faster-than-light travel, and I give an example of a metric which appears to allow superluminal travel, but in fact is just flat space. To avoid such difficulties, I propose a definition of superluminal travel which requires that the path to be traveled reach a destination surface at an earlier time than any neig...

  2. Staying Healthy While You Travel (For Parents)

    Science.gov (United States)

    ... Pregnant? Your Baby's Growth Staying Healthy While You Travel KidsHealth > For Parents > Staying Healthy While You Travel ... your family prepares to travel. Special Considerations for Travel Abroad If you're heading overseas, start preparing ...

  3. Just the Facts: Traveling on Dialysis

    Science.gov (United States)

    Just the Facts: Traveling on Dialysis Why is travel important to me? Travel, especially for vacation, is fun! Changing your routines and seeing ... places is refreshing, and can lift your spirits. Travel allows you to stay close to special people ...

  4. The effect of scene content on speed, time, and distance perception

    Science.gov (United States)

    Awe, Cynthia A.; Johnson, Walter W.

    1993-01-01

    Helicopter flights performed at low-levels place high demands on pilots; they must simultaneously control the vehicle, avoid obstacles, and navigate. Therefore, pilots must correlate cues viewed in the external scene with information on map in order to maintain their geographical orientation. This is a particularly difficult task when helicopter pilots fly through visually unfamiliar terrain without highly detailed maps. As a result, pilots must often use estimates of elapsed time, distance traveled, and/or average speed in order to maintain a flight path indicated on a map during flight segments when these cues are absent. Therefore, the current study is concerned with the perception of speed, time, and distance, which we assume underlies the ability to orient oneself during these types of flight segments.

  5. Travelling Waves in Hybrid Chemotaxis Models

    KAUST Repository

    Franz, Benjamin

    2013-12-18

    Hybrid models of chemotaxis combine agent-based models of cells with partial differential equation models of extracellular chemical signals. In this paper, travelling wave properties of hybrid models of bacterial chemotaxis are investigated. Bacteria are modelled using an agent-based (individual-based) approach with internal dynamics describing signal transduction. In addition to the chemotactic behaviour of the bacteria, the individual-based model also includes cell proliferation and death. Cells consume the extracellular nutrient field (chemoattractant), which is modelled using a partial differential equation. Mesoscopic and macroscopic equations representing the behaviour of the hybrid model are derived and the existence of travelling wave solutions for these models is established. It is shown that cell proliferation is necessary for the existence of non-transient (stationary) travelling waves in hybrid models. Additionally, a numerical comparison between the wave speeds of the continuum models and the hybrid models shows good agreement in the case of weak chemotaxis and qualitative agreement for the strong chemotaxis case. In the case of slow cell adaptation, we detect oscillating behaviour of the wave, which cannot be explained by mean-field approximations. © 2013 Society for Mathematical Biology.

  6. Mathematical description of bacterial traveling pulses.

    Directory of Open Access Journals (Sweden)

    Jonathan Saragosti

    Full Text Available The Keller-Segel system has been widely proposed as a model for bacterial waves driven by chemotactic processes. Current experiments on Escherichia coli have shown the precise structure of traveling pulses. We present here an alternative mathematical description of traveling pulses at the macroscopic scale. This modeling task is complemented with numerical simulations in accordance with the experimental observations. Our model is derived from an accurate kinetic description of the mesoscopic run-and-tumble process performed by bacteria. This can account for recent experimental observations with E. coli. Qualitative agreements include the asymmetry of the pulse and transition in the collective behaviour (clustered motion versus dispersion. In addition, we can capture quantitatively the traveling speed of the pulse as well as its characteristic length. This work opens several experimental and theoretical perspectives since coefficients at the macroscopic level are derived from considerations at the cellular scale. For instance, the particular response of a single cell to chemical cues turns out to have a strong effect on collective motion. Furthermore, the bottom-up scaling allows us to perform preliminary mathematical analysis and write efficient numerical schemes. This model is intended as a predictive tool for the investigation of bacterial collective motion.

  7. Traveling waves for the FitzHugh-Nagumo system on an infinite channel

    Science.gov (United States)

    Chen, Chao-Nien; Chen, Chiun-Chuan; Huang, Chih-Chiang

    2016-09-01

    We are concerned with the traveling wave solutions for the FitzHugh-Nagumo system on an infinite channel. Based on a variational formulation in which a non-local term depends on a parameter, the speed of a traveling wave can be selected out. Furthermore, to show the existence of a traveling wave solution with such a speed, we seek a minimizer subject to a constraint. In the way of solving the variational problem, we apply a truncation technique to the nonlocal term to obtain a minimizer located in a bounded invariant region.

  8. The SUN S TRAVELS

    Institute of Scientific and Technical Information of China (English)

    Robert; Louis; Stevenson

    2005-01-01

    The sun is not a-bed, when I At night upon my pillow lie; Stilt round the earth his Way he takes, And morning after morning makes. White here at home, in shining day, We round the sunny garden play, Each tittle Indian sleepy - head Is being kissed and put to bed. And When at eve I rise from tea, Day dawns beyond the Atlantic Sea; And all the children in the West Are getting up and being dressed.The SUN'S TRAVELS@Robert Louis Stevenson

  9. Travelling fronts in stochastic Stokes’ drifts

    KAUST Repository

    Blanchet, Adrien

    2008-10-01

    By analytical methods we study the large time properties of the solution of a simple one-dimensional model of stochastic Stokes\\' drift. Semi-explicit formulae allow us to characterize the behaviour of the solutions and compute global quantities such as the asymptotic speed of the center of mass or the effective diffusion coefficient. Using an equivalent tilted ratchet model, we observe that the speed of the center of mass converges exponentially to its limiting value. A diffuse, oscillating front attached to the center of mass appears. The description of the front is given using an asymptotic expansion. The asymptotic solution attracts all solutions at an algebraic rate which is determined by the effective diffusion coefficient. The proof relies on an entropy estimate based on homogenized logarithmic Sobolev inequalities. In the travelling frame, the macroscopic profile obeys to an isotropic diffusion. Compared with the original diffusion, diffusion is enhanced or reduced, depending on the regime. At least in the limit cases, the rate of convergence to the effective profile is always decreased. All these considerations allow us to define a notion of efficiency for coherent transport, characterized by a dimensionless number, which is illustrated on two simple examples of travelling potentials with a sinusoidal shape in the first case, and a sawtooth shape in the second case. © 2008 Elsevier B.V. All rights reserved.

  10. Traveling time and traveling length for flow in porous media

    OpenAIRE

    Lee, Youngki; Andrade Jr., Jose S.; Buldyrev, Sergey V.; Dokholyan, Nikolay V.; Havlin, Shlomo; King, Peter R.; Paul, Gerald; Stanley, H. Eugene

    1999-01-01

    We study traveling time and traveling length for tracer dispersion in porous media. We model porous media by two-dimensional bond percolation, and we model flow by tracer particles driven by a pressure difference between two points separated by Euclidean distance $r$. We find that the minimal traveling time $t_{min}$ scales as $t_{min} \\sim r^{1.40}$, which is different from the scaling of the most probable traveling time, ${\\tilde t} \\sim r^{1.64}$. We also calculate the length of the path c...

  11. TECHNICAL APPROACH TO THE EFFICIENCY DETERMINATION OF HIGH-SPEED TRAINS

    Directory of Open Access Journals (Sweden)

    A. V. Momot

    2013-11-01

    Full Text Available Purpose. The aim of this article is to develop an approach and formulate arrangements concerning the definition of the economic appropriateness of high-speed movement implementation in Ukraine. Methodology. The economic feasibility for appropriateness of high-speed movement organization in Ukraine is an investment project, which involves step-by-step money investment into the construction. It will let get an annual profits from the passenger carriage. To solve such problems we use net present value, which UZ or newly created companies can get during the project realization and after its completion. Findings. Obtained studies can state the fact that the technical approach for full effectiveness definition of a construction and high-speed passenger trains service taking into account the cost of infrastructure, rolling stock, the impact of environmental factors, etc. was determined. Originality. We propose a scientific approach to determine the economic effectiveness of the construction and high-speed main lines service. It includes improved principles of defining the passenger traffic, the cost of high-speed rails construction, the number of rolling stock; optimizes income and expenditure calculations in the context of competitive advantages and the external factors impact on the company. A technical approach for the calculation of future traffic volumes along the high-speed line was improved. It differs essentially from the European one proposed by the French firm «SYSTRA», as it allows taking into account additional transit traffic through Ukraine. It helps to distribute the passengers on separate sections proportionally to the number of cities population, which are combined by high-speed main line, subject to the average population mobility, travel time and the coefficient that takes into account the frequency of additional passenger trips on a given section, depending on the purpose (business trip, transfer to a plane, recreation, etc

  12. Average Convexity in Communication Situations

    NARCIS (Netherlands)

    Slikker, M.

    1998-01-01

    In this paper we study inheritance properties of average convexity in communication situations. We show that the underlying graph ensures that the graphrestricted game originating from an average convex game is average convex if and only if every subgraph associated with a component of the underlyin

  13. Traveling-Wave Tubes

    Science.gov (United States)

    Kory, Carol L.

    1998-01-01

    The traveling-wave tube (TWT) is a vacuum device invented in the early 1940's used for amplification at microwave frequencies. Amplification is attained by surrendering kinetic energy from an electron beam to a radio frequency (RF) electromagnetic wave. The demand for vacuum devices has been decreased largely by the advent of solid-state devices. However, although solid state devices have replaced vacuum devices in many areas, there are still many applications such as radar, electronic countermeasures and satellite communications, that require operating characteristics such as high power (Watts to Megawatts), high frequency (below 1 GHz to over 100 GHz) and large bandwidth that only vacuum devices can provide. Vacuum devices are also deemed irreplaceable in the music industry where musicians treasure their tube-based amplifiers claiming that the solid-state and digital counterparts could never provide the same "warmth" (3). The term traveling-wave tube includes both fast-wave and slow-wave devices. This article will concentrate on slow-wave devices as the vast majority of TWTs in operation fall into this category.

  14. The difference between alternative averages

    Directory of Open Access Journals (Sweden)

    James Vaupel

    2012-09-01

    Full Text Available BACKGROUND Demographers have long been interested in how compositional change, e.g., change in age structure, affects population averages. OBJECTIVE We want to deepen understanding of how compositional change affects population averages. RESULTS The difference between two averages of a variable, calculated using alternative weighting functions, equals the covariance between the variable and the ratio of the weighting functions, divided by the average of the ratio. We compare weighted and unweighted averages and also provide examples of use of the relationship in analyses of fertility and mortality. COMMENTS Other uses of covariances in formal demography are worth exploring.

  15. Traveling waves of infection in the Hantavirus epidemics

    CERN Document Server

    Abramson, G; Yates, T L; Parmenter, R R

    2002-01-01

    Traveling waves are analyzed in a model of the Hantavirus infection of deer mice. The existence of two kinds of wave phenomena is predicted. An environmental parameter governs a transition between two regimes of propagation. In one of them the front of infection lags behind at a constant rate. In the other, fronts of susceptible and infected mice travel at the same speed, separated by a constant delay. The dependence of the delay on system parameters is analyzed numerically and through a piecewise linearization.

  16. Communication from Carlson Wagonlit Travel

    CERN Multimedia

    2008-01-01

    Entry requirements for the USA: "ESTA" (Electronic System for Travel Authorization) online registration The requirement to register before entering the USA announced by the Department of Homeland Security (DHS) is to be introduced on 12 January 2009. Visitors to the USA will then be required to register their personal data and travel data online not less than 72 hours prior to travel. https://esta.cbp.dhs.gov/ General information on entry requirements for the USA are also available on the Carlson Wagonlit Travel website under the heading „CWT informs": http://www.carlsonwagonlit.ch

  17. Communication from Carlson Wagonlit Travel

    CERN Multimedia

    2009-01-01

    Entry requirements for the USA: "ESTA" (Electronic System for Travel Authorization) online registration The requirement to register before entering the USA announced by the Department of Homeland Security (DHS) is to be introduced on 12 January 2009. Visitors to the USA will then be required to register their personal data and travel data online not less than 72 hours prior to travel. https://esta.cbp.dhs.gov/ General information on entry requirements for the USA is also available on the Carlson Wagonlit Travel website under the heading „CWT informs": http://www.carlsonwagonlit.ch

  18. Vehicle speed control transition module and method

    Energy Technology Data Exchange (ETDEWEB)

    Mangan, E.L.; Conklin, B.

    1986-12-16

    An apparatus is described for automatically controlling the speed of a driverless vehicle comprising a stationary frame supporting first, second and third aligned drive tubes between tracks on the frame and which are adapted to support a driverless vehicle. A means is included for independently driving the first, second and third drive tubes such that each tube, when driven, rotates about its longitudinal axis, sensor means disposed along the frame for actuation by a driverless vehicle. The means for independently driving the drive tubes includes variable speed drive means responsive to the sensor means fro driving the second tube between first and second speeds. A method is described of automatically controlling the speed of a driverless vehicle which travels along first, second and third aligned drive tubes by frictional contact therewith. It maintains the first, second, and third drive tubes out of mechanical engagement with each other at all times, sensing the location of the driverless vehicle, driving the first drive tube at a first speed, driving the third drive tube at a second at a second speed. It also varies the speed of the second drive tube from the first speed to the second speed based on the sensed location of the driverless vehicle while the vehicle is driven by contact with the second drive tube.

  19. A study on the Antarctic circumpolar wave mode-A coexistence system of standing and traveling wave

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Antarctic circumpolar wave (ACW) has become a focus of the air-sea coupled Southern Ocean study since 1996, when it was discovered as an air-sea coupled interannual signal propagating eastward in the region of the Antarctic Circumpolar Current (ACC). In order to analyze the mechanism of discontinuity along the latitudinal propagation, a new idea that ACW is a system with a traveling wave in the Southern Pacific and Atlantic Ocean and with a concurrent standing wave in the southern Indian Ocean is proposed in this paper. Based on the ideal wave principle, the average wave parameters of ACW is achieved using a non-linear approximation method, by which we find that the standing part and the traveling part possess similar radius frequency, proving their belonging to an integral system. We also give the latitudinal distribution of wave speed with which we could tell the reason for steady propagation during the same period. The spatial distribution of the propagation reveals complex process with variant spatial and temporal scales-The ENSO scale oscillation greatly impacts on the traveling process, while the result at the south of Australia indicates little connection between the Indian Ocean and the Pacific, which may be blocked by the vibration at the west of the Pacific. The advective effect of ACC on the propagation process should be examined clearly through dynamical method.

  20. Amebic Liver Abscess in Israeli Travelers: A Retrospective Study.

    Science.gov (United States)

    Lachish, Tamar; Wieder-Finesod, Anat; Schwartz, Eli

    2016-05-01

    Amebic liver abscess (ALA) is endemic in developing countries. The epidemiology and clinical characteristics of the disease in developing countries are well described. Travelers from nonendemic countries can serve as a model for the natural history of ALA. Currently, the available literature on travelers is limited. This is a retrospective observational study on Israeli travelers diagnosed with ALA. Data regarding travel history, clinical presentation, imaging, and treatment were collected and analyzed. Among 6,867 ill returning Israeli travelers, amebiasis was diagnosed in 53 travelers (0.77%), of whom 14 were with ALA (0.2%). Twelve ALA cases (86%) had an exposure in the Indian subcontinent. The male to female ratio was 1:1, with no significant clinical differences between the sexes. The average lag period between exposure and onset of symptoms was 17.1 months. The lack of male predominance and the prolonged lag period may imply that behavioral factors are pivotal in the development of ALA. Larger case series of travelers are required. PMID:26928829

  1. Commuters' Preferences for Fast and Reliable Travel

    OpenAIRE

    Koster, Paul; Koster, Hans,

    2013-01-01

    Traffic congestion contributes to longer travel times and increased travel time variability. We account for the dynamic nature of travellers' choices, by deriving a closed-form solution for the costs of travel time variability. The resulting travel delay cost function is linear in the mean travel delay. Then, we use a semiparametric estimation approach to analyse observed and unobserved heterogeneity in the value of travel time and reliability. Using data from a stated choice experiment, we s...

  2. Stimulus motion propels traveling waves in binocular rivalry.

    Directory of Open Access Journals (Sweden)

    Tomas Knapen

    Full Text Available State transitions in the nervous system often take shape as traveling waves, whereby one neural state is replaced by another across space in a wave-like manner. In visual perception, transitions between the two mutually exclusive percepts that alternate when the two eyes view conflicting stimuli (binocular rivalry may also take shape as traveling waves. The properties of these waves point to a neural substrate of binocular rivalry alternations that have the hallmark signs of lower cortical areas. In a series of experiments, we show a potent interaction between traveling waves in binocular rivalry and stimulus motion. The course of the traveling wave is biased in the motion direction of the suppressed stimulus that gains dominance by means of the wave-like transition. Thus, stimulus motion may propel the traveling wave across the stimulus to the extent that the stimulus motion dictates the traveling wave's direction completely. Using a computational model, we show that a speed-dependent asymmetry in lateral inhibitory connections between retinotopically organized and motion-sensitive neurons can explain our results. We argue that such a change in suppressive connections may play a vital role in the resolution of dynamic occlusion situations.

  3. Analysis of the circular track experiment measuring the one-way speed of light

    OpenAIRE

    Philip, Evan John

    2012-01-01

    All experiments attempting to verify the invariance of speed of light directly are based on two-way speed measurement. The challenge in one-way speed measurement, the requirement of spatially separated synchronised clocks, can be possibly circumvented by measuring the speed of light travelling in a closed path. An apparent violation of the invariance principle has been recently reported in the first experiment attempting to measure the one-way speed of light utilising this concept. This exper...

  4. Predicting travel time and dispersion in rivers and streams

    Science.gov (United States)

    Jobson, H.E.

    1997-01-01

    The possibility of a contaminant being accidentally or intentionally spilled in a river is a constant concern to those using the water. Methods are developed to estimate: (1) the velocity of a contaminant in a river; (2) the rate of attenuation of the peak concentration of a conservative contaminant; and (3) the time required for a contaminant plume to pass a point. The methods are based on data collected by the U.S. Geological Survey in almost a hundred different rivers representing a wide range of sizes, slopes, and geomorphic types. Although the accuracy of the predictions can be greatly increased by performing time-of-travel studies, the emphasis of this paper is on providing methods for making estimates where few data are available. It is shown that the unit-peak concentration is well correlated with travel time and that the travel time of the leading edge averages 89% of the travel time of the peak concentration.

  5. Solar wind travel time

    Science.gov (United States)

    Russell, C. T.

    A useful rule of thumb in solar terrestrial studies is that the solar wind travels 4 Earth radii (RE) per minute. Long-term studies of solar wind velocity [e.g., Luhmann et al., 1993; 1994] show that the median velocity is about 420 km/s, corresponding to 3.96 RE min-1. The quartiles are about 370 km/s and 495 km/s, corresponding to 3.48 Re min-1 and 4.66 Re min-1 respectively. This number helps estimate the delays expected when observing a discontinuity at a solar wind monitor; one example is ISEE-3 when it was at the forward libration point (about 60 min). It is also helpful for estimating how much time passes before the dayside magnetosphere is compressed as denser solar wind flows by (about 2.5 min).

  6. The Electromechanical Behavior of a Micro-Ring Driven by Traveling Electrostatic Force

    Directory of Open Access Journals (Sweden)

    Kuo-Yi Huang

    2012-01-01

    Full Text Available There is no literature mentioning the electromechanical behavior of micro structures driven by traveling electrostatic forces. This article is thus the first to present the dynamics and stabilities of a micro-ring subjected to a traveling electrostatic force. The traveling electrostatic force may be induced by sequentially actuated electrodes which are arranged around the flexible micro-ring. The analysis is based on a linearized distributed model considering the electromechanical coupling effects between electrostatic force and structure. The micro-ring will resonate when the traveling speeds of the electrostatic force approach some critical speeds. The critical speeds are equal to the ratio of the natural frequencies to the wave number of the correlative natural mode of the ring. Apart from resonance, the ring may be unstable at some unstable traveling speeds. The unstable regions appear not only near the critical speeds, but also near some fractions of some critical speeds differences. Furthermore the unstable regions expand with increasing driving voltage. This article may lead to a new research branch on electrostatic-driven micro devices.

  7. Determination of Scheduled Travel Time for a Fixed Transit Route Based on Multistate Model

    Institute of Scientific and Technical Information of China (English)

    Shukai Chen; Daniel Jian Sun; and Rui Xue

    2016-01-01

    In order to provide the guideline for bus drivers to adjust speed to minimize scheduled deviation, the method for setting bus scheduled travel time is proposed. Firstly, multistate model is introduced to fit historical travel time data and identify different service states. Based on the calibrated travel time distribution parameters, an optimization model is proposed, followed by a Monte Carlo ( MC) simulation based genetic algorithm ( GA) procedure to obtain the optimal scheduled time. A case study from a fixed bus route from Shenzhen is used to demonstrate the model applicability. The sensitivity analysis is conducted to study the effects of parameters setting on optimal slack time for each segment. The results show that multistate model fits travel time under peak hours better than Lognormal distribution, and the length of scheduled travel time basically reflects travel time reliability.

  8. EFFECT OF CONGESTION ON FUEL COST AND TRAVEL TIME COST ON MULTI-LANE HIGHWAYS IN INDIA

    Directory of Open Access Journals (Sweden)

    Madhu Errampalli

    2015-12-01

    Full Text Available The vehicles normally move at their free speeds when it is least impeded due to traffic flow under lean traffic (free flow conditions. As traffic flow increases, the vehicles cannot sustain their free speeds due to interactions from other vehicles in the traffic stream. In addition to that the vehicles that are operating in the congested traffic conditions will consume more fuel than those operating in steady state traffic conditions for the same average speed. This leads to increase in travel time and fuel consumption of the vehicles and thereby adding to total road user cost (RUC. On the contrary, fuel consumption is also high at very high speeds under free flow traffic flow conditions leading to increase RUC. Considering these scenarios, the travel time and fuel cost of the vehicle due to the congestion and free flow conditions (uncongested has to be necessarily modelled in order to estimate realistic assessment of RUC on Indian highways. In the present study, the congestion cost relationships have been developed between Congestion Factor, a ratio of cost under congestion and steady state conditions and Volume-Capacity Ratio by considering various vehicle types plying on varying widths of multi-lane highways (four, six and eight lane divided carriageways through the collection of exhaustive time related and fuel related data. Time related data was collected through questionnaire survey method whereas fuel consumption data was collected using advanced sophisticated fuel flow measuring equipment (V-Box. The developed equations have been successfully applied to demonstrate their applicability in terms of estimating realistic effect of congestion on time and fuel cost by considering a section on NH-2 in Delhi. The analysis shows that the congestion effect is more significant on fuel cost for heavy commercial vehicles whereas it is more prominent on time cost for passenger vehicles. However, the congestion effect on combined fuel and time cost is

  9. Physical Theories with Average Symmetry

    CERN Document Server

    Alamino, Roberto C

    2013-01-01

    This Letter probes the existence of physical laws invariant only in average when subjected to some transformation. The concept of a symmetry transformation is broadened to include corruption by random noise and average symmetry is introduced by considering functions which are invariant only in average under these transformations. It is then shown that actions with average symmetry obey a modified version of Noether's Theorem with dissipative currents. The relation of this with possible violations of physical symmetries, as for instance Lorentz invariance in some quantum gravity theories, is briefly commented.

  10. The role of the harmonic vector average in motion integration

    OpenAIRE

    Alan eJohnston; Peter eScarfe

    2013-01-01

    The local speeds of object contours vary systematically with the cosine of the angle between the normal component of the local velocity and the global object motion direction. An array of Gabor elements whose speed changes with local spatial orientation in accordance with this pattern can appear to move as a single surface. The apparent direction of motion of plaids and Gabor arrays has variously been proposed to result from feature tracking, vector addition and vector averaging in addition t...

  11. Immunization for children traveling abroad.

    Science.gov (United States)

    Sood, S K

    2000-04-01

    More children are travelling these days, often to underdeveloped countries with high prevalence of vaccine-preventable vector-borne, food-borne, zoonotic, and other infections. The pretravel office visit involves consideration of routine and travel vaccines. Epidemiology of typhoid fever, rabies, yellow fever, Japanese encephalitis, vaccines against them, and their recommended use are reviewed. PMID:10761513

  12. Travel and Adult Transformative Learning

    Science.gov (United States)

    Lindstrom, Steven K.

    2011-01-01

    This phenomenological research study examines the lived experience of individual adult transformation in the context of travel. Adults throughout history have experienced profound personal and perception changes as a result of significant travel events. Transformative learning occurs through experience, crisis, and reflection, all of which are…

  13. Traveler's Health: Avoid Bug Bites

    Science.gov (United States)

    ... Guide Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart Plan Ahead ... During Trip After Your Trip CDC-TV Videos Travel to the Olympics ... Presentations for Health Professionals Yellow Fever Vaccine Course About the Yellow ...

  14. Carlson Wagonlit Travel is moving

    CERN Multimedia

    2013-01-01

    The renovation of the Main Building continues!   Because of this, Carlson Wagonlit Travel will move from building 62 to building 510 on 4 October and the agency will be closed in the afternoon. An emergency service will be organised for official travels only. Phone: 022 799 75 73 & 022 799 75 78 / e-mail: cern@carlsonwagonlit.ch

  15. 75 FR 43395 - Campaign Travel

    Science.gov (United States)

    2010-07-26

    ... Campaign Travel AGENCY: Federal Election Commission. ACTION: Announcement of effective date. SUMMARY: On... of the Honest Leadership and Open Government Act governing campaign travel on noncommercial aircraft. This document announces the effective date of amendments made by those final rules to...

  16. Traveling Wave Solutions for Lotka-Volterra System Re-Visited

    CERN Document Server

    Leung, Anthony W; Feng, Wei

    2009-01-01

    Using a new method of monotone iteration of a pair of smooth lower- and upper-solutions, the traveling wave solutions of the classical Lotka-Volterra system are shown to exist for a family of wave speeds. Such constructed upper and lower solution pair enables us to derive the explicit value of the minimal (critical) wave speed as well as the asymptotic rates of the wave solutions at infinities. Furthermore, the traveling wave corresponding to each wave speed is unique modulo a translation of the origin. The stability of the traveling wave solutions with non-critical wave speed is also studied by spectral analysis of the linearized operator in exponentially weighted Banach spaces.

  17. Monitoring Travel Time Reliability on Freeways

    NARCIS (Netherlands)

    Tu, Huizhao

    2008-01-01

    Travel time and travel time reliability are important attributes of a trip. The current measures of reliability have in common that in general they all relate to the variability of travel times. However, travel time reliability does not only rely on variability but also on the stability of travel ti

  18. 49 CFR 229.55 - Piston travel.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Piston travel. 229.55 Section 229.55... Piston travel. (a) Brake cylinder piston travel shall be sufficient to provide brake shoe clearance when... piston travel may not exceed 11/2 inches less than the total possible piston travel. The total...

  19. Elasticity of Long Distance Travelling

    DEFF Research Database (Denmark)

    Knudsen, Mette Aagaard

    2011-01-01

    With data from the Danish expenditure survey for 12 years 1996 through 2007, this study analyses household expenditures for long distance travelling. Household expenditures are examined at two levels of aggregation having the general expenditures on transportation and leisure relative to five other...... aggregated commodities at the highest level, and the specific expenditures on plane tickets and travel packages at the lowest level. The Almost Ideal Demand System is applied to determine the relationship between expenditures on transportation and leisure and all other purchased non-durables within...... a household. Due to a high share of corner solutions among the expenditures on plane tickets and package travelling, the expenditures on these specific commodities are examined with a Tobit approach. The model results find both plane tickets and travel packages to be luxury goods. It also states that travel...

  20. "Pricing Average Options on Commodities"

    OpenAIRE

    Kenichiro Shiraya; Akihiko Takahashi

    2010-01-01

    This paper proposes a new approximation formula for pricing average options on commodities under a stochastic volatility environment. In particular, it derives an option pricing formula under Heston and an extended lambda-SABR stochastic volatility models (which includes an extended SABR model as a special case). Moreover, numerical examples support the accuracy of the proposed average option pricing formula.

  1. Quantized average consensus with delay

    NARCIS (Netherlands)

    Jafarian, Matin; De Persis, Claudio

    2012-01-01

    Average consensus problem is a special case of cooperative control in which the agents of the network asymptotically converge to the average state (i.e., position) of the network by transferring information via a communication topology. One of the issues of the large scale networks is the cost of co

  2. Dynamics of travelling waves in visual perception.

    Science.gov (United States)

    Wilson, H R; Blake, R; Lee, S H

    2001-08-30

    Nonlinear wave propagation is ubiquitous in nature, appearing in chemical reaction kinetics, cardiac tissue dynamics, cortical spreading depression and slow wave sleep. The application of dynamical modelling has provided valuable insights into the mechanisms underlying such nonlinear wave phenomena in several domains. Wave propagation can also be perceived as sweeping waves of visibility that occur when the two eyes view radically different stimuli. Termed binocular rivalry, these fluctuating states of perceptual dominance and suppression are thought to provide a window into the neural dynamics that underlie conscious visual awareness. Here we introduce a technique to measure the speed of rivalry dominance waves propagating around a large, essentially one-dimensional annulus. When mapped onto visual cortex, propagation speed is independent of eccentricity. Propagation speed doubles when waves travel along continuous contours, thus demonstrating effects of collinear facilitation. A neural model with reciprocal inhibition between two layers of units provides a quantitative explanation of dominance wave propagation in terms of disinhibition. Dominance waves provide a new tool for investigating fundamental cortical dynamics. PMID:11528478

  3. The travel-related carbon dioxide emissions of atmospheric researchers

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2008-11-01

    Full Text Available Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who – like other scientists – rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of CO2. In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc. were calculated for the years 2005–2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.

  4. The travel-related carbon dioxide emissions of atmospheric researchers

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2008-04-01

    Full Text Available Most atmospheric scientists agree that greenhouse gas emissions have already caused significant changes to the global climate system and that these changes will accelerate in the near future. At the same time, atmospheric scientists who – like other scientists – rely on international collaboration and information exchange travel a lot and, thereby, cause substantial emissions of carbon dioxide (CO2. In this paper, the CO2 emissions of the employees working at an atmospheric research institute (the Norwegian Institute for Air Research, NILU caused by all types of business travel (conference visits, workshops, field campaigns, instrument maintainance, etc. were calculated for the years 2005–2007. It is estimated that more than 90% of the emissions were caused by air travel, 3% by ground travel and 5% by hotel usage. The travel-related annual emissions were between 1.9 and 2.4 t CO2 per employee or between 3.9 and 5.5 t CO2 per scientist. For comparison, the total annual per capita CO2 emissions are 4.5 t worldwide, 1.2 t for India, 3.8 t for China, 5.9 t for Sweden and 19.1 t for Norway. The travel-related CO2 emissions of a NILU scientist, occurring in 24 days of a year on average, exceed the global average annual per capita emission. Norway's per-capita CO2 emissions are among the highest in the world, mostly because of the emissions from the oil industry. If the emissions per NILU scientist derived in this paper are taken as representative for the average Norwegian researcher, travel by Norwegian scientists would nevertheless account for a substantial 0.2% of Norway's total CO2 emissions. Since most of the travel-related emissions are due to air travel, water vapor emissions, ozone production and contrail formation further increase the relative importance of NILU's travel in terms of radiative forcing.

  5. 2001 New York State NHTS: Travel Patterns of Special Populations

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Patricia S [ORNL; Reuscher, Tim [ORNL

    2010-03-01

    Policymakers rely on transportation statistics, including data on personal travel behavior, to formulate strategic transportation policies, and to improve the safety and efficiency of the U.S. transportation system. Data on personal travel trends are needed to examine the reliability, efficiency, capacity, and flexibility of the Nation's transportation system to meet current demands and accommodate future demands; to assess the feasibility and efficiency of alternative congestion-alleviating technologies (e.g., high-speed rail, magnetically levitated trains, intelligent vehicle and highway systems); to evaluate the merits of alternative transportation investment programs; and to assess the energy-use and air-quality impacts of various policies. To address these data needs, the U.S. Department of Transportation (USDOT) initiated an effort in 1969 to collect detailed data on personal travel. The 1969 survey was the first Nationwide Personal Transportation Survey (NPTS). The survey was conducted again in 1977, 1983, 1990, 1995, and 2001. Data on daily travel were collected in 1969, 1977, 1983, 1990 and 1995. Longer-distance travel was collected in 1977 and 1995. The 2001 National Household Travel Survey (NHTS) collected both daily and longer-distance trips in one survey. The 2001 survey was sponsored by three USDOT agencies: Federal Highway Administration (FHWA), Bureau of Transportation Statistics (BTS), and National Highway Traffic Safety Administration (NHTSA). The primary objective of the survey was to collect trip-based data on the nature and characteristics of personal travel so that the relationships between the characteristics of personal travel and the demographics of the traveler can be established. Commercial and institutional travel was not part of the survey. New York State participated in the 2001 NHTS by procuring additional 12,000 sample households. These additional sample households allowed New York State to address transportation planning issues

  6. Human cortical traveling waves: dynamical properties and correlations with responses.

    Directory of Open Access Journals (Sweden)

    Timothy M Patten

    Full Text Available The spatiotemporal behavior of human EEG oscillations is investigated. Traveling waves in the alpha and theta ranges are found to be common in both prestimulus and poststimulus EEG activity. The dynamical properties of these waves, including their speeds, directions, and durations, are systematically characterized for the first time, and the results show that there are significant changes of prestimulus spontaneous waves in the presence of an external stimulus. Furthermore, the functional relevance of these waves is examined by studying how they are correlated with reaction times on a single trial basis; prestimulus alpha waves traveling in the frontal-to-occipital direction are found to be most correlated to reaction speeds. These findings suggest that propagating waves of brain oscillations might be involved in mediating long-range interactions between widely distributed parts of human cortex.

  7. Tips for Traveling with HomePEN

    Science.gov (United States)

    ... Keep Private Resources: Travel Tips Share | Tips for Traveling with HomePEN A little preparation can go a ... on your Behalf (12/2010) Other Articles on Travel TSA Program Aims to Help Elderly, Disabled, Sick ...

  8. Traveling with Inflammatory Bowel Disease (IBD)

    Science.gov (United States)

    ... Center Home > Resources > Traveling With IBD Go Back Traveling With IBD Email Print + Share Don't avoid ... the States, these tips will come in handy. Travel Tips for Vacation Time Locating A Doctor Ask ...

  9. 76 FR 43236 - Federal Travel Regulation (FTR): Temporary Duty (TDY) Travel Allowances: Notice of Public Meeting

    Science.gov (United States)

    2011-07-20

    ... ADMINISTRATION 41 CFR Chapter 301 Federal Travel Regulation (FTR): Temporary Duty (TDY) Travel Allowances: Notice... Federal Travel Regulation (FTR) in an effort to streamline travel policies, increase travel efficiency and... pertain to Temporary Duty (TDY) Travel Allowances that include special conveyances, per diem and...

  10. Carlson Wagonlit Travel

    CERN Multimedia

    Carlson Wagonlit Travel

    2005-01-01

    Chères clientes, chers clients, Le 3 janvier dernier, nous vous avons informé de la décision des compagnies aériennes de supprimer les commissions versées aux agences de voyages suisses. Cette mesure a été introduite progressivement pour être appliquées maintenant par toutes les compagnies, à quelques rares exceptions près. En conséquence, en accord avec le CERN, nous serons dans l'obligation d'appliquer une nouvelle liste de prix de nos transactions pour les voyages privés. Elle sera applicable dès le lundi 25 juillet 2005. Carlson Wagonlit Travel (CWT) vous propose : Son service de conseil personnalisé, professionnel et compétent Sa recherche de la solution la plus économique et la mieux adaptée à vos besoins Sa neutralité dans les comparaisons de prix et prestations Des informations com...

  11. On the impossibility of superluminal travel: the warp drive lesson

    CERN Document Server

    Barceló, Carlos; Liberati, Stefano

    2010-01-01

    The question of whether it is possible or not to surpass the speed of light is already centennial. The special theory of relativity took the existence of a speed limit as a principle, the light postulate, which has proven to be enormously predictive. Here we discuss some of its twists and turns when general relativity and quantum mechanics come into play. In particular, we discuss one of the most interesting proposals for faster than light travel: warp drives. Even if one succeeded in creating such spacetime structures, it would be still necessary to check whether they would survive to the switching on of quantum matter effects. Here, we show that the quantum back-reaction to warp-drive geometries, created out of an initially flat spacetime, inevitably lead to their destabilization whenever superluminal speeds are attained. We close this investigation speculating the possible significance of this further success of the speed of light postulate.

  12. Gaussian moving averages and semimartingales

    DEFF Research Database (Denmark)

    Basse-O'Connor, Andreas

    2008-01-01

    In the present paper we study moving averages (also known as stochastic convolutions) driven by a Wiener process and with a deterministic kernel. Necessary and sufficient conditions on the kernel are provided for the moving average to be a semimartingale in its natural filtration. Our results...... are constructive - meaning that they provide a simple method to obtain kernels for which the moving average is a semimartingale or a Wiener process. Several examples are considered. In the last part of the paper we study general Gaussian processes with stationary increments. We provide necessary and sufficient...

  13. The warp drive hyper-fast travel within general relativity

    CERN Document Server

    Alcubierre, M

    1994-01-01

    It is shown how, within the framework of general relativity and without the introduction of wormholes, it is possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the ``warp drive'' of science fiction. However, just as it happens with wormholes, exotic matter will be needed in order to generate a distortion of spacetime like the one discussed here.

  14. On the impossibility of superluminal travel: the warp drive lesson

    OpenAIRE

    Barceló, Carlos; Finazzi, Stefano; Liberati, Stefano

    2010-01-01

    The question of whether it is possible or not to surpass the speed of light is already centennial. The special theory of relativity took the existence of a speed limit as a principle, the light postulate, which has proven to be enormously predictive. Here we discuss some of its twists and turns when general relativity and quantum mechanics come into play. In particular, we discuss one of the most interesting proposals for faster than light travel: warp drives. Even if one succeeded in creatin...

  15. The warp drive: hyper-fast travel within general relativity

    OpenAIRE

    Alcubierre, Miguel

    2000-01-01

    It is shown how, within the framework of general relativity and without the introduction of wormholes, it is possible to modify a spacetime in a way that allows a spaceship to travel with an arbitrarily large speed. By a purely local expansion of spacetime behind the spaceship and an opposite contraction in front of it, motion faster than the speed of light as seen by observers outside the disturbed region is possible. The resulting distortion is reminiscent of the ``warp drive'' of science f...

  16. Experienced travel time prediction for congested freeways

    OpenAIRE

    Yildirimoglu, Mehmet; Geroliminis, Nikolaos

    2013-01-01

    Travel time is an important performance measure for transportation systems, and dissemination of travel time information can help travelers make reliable travel decisions such as route choice or departure time. Since the traffic data collected in real time reflects the past or current conditions on the roadway, a predictive travel time methodology should be used to obtain the information to be disseminated. However, an important part of the literature either uses instantaneous travel time ass...

  17. Travelers' Health: Traveling Safely with Infants and Children

    Science.gov (United States)

    ... Chapter 2, Protection against Mosquitoes, Ticks, & Other Arthropods . DENGUE AND OTHER ARBOVIRUSES Pediatric VFR travelers who may ... risk similar to children living in areas where dengue or other arboviruses (such as chikungunya, Japanese encephalitis, ...

  18. Fault location method for transmission line based on traveling waves

    Institute of Scientific and Technical Information of China (English)

    ZHENG Na; ZHAO Yulin

    2007-01-01

    The single phase grounding fault location is the focus which researchers pay attention to and study in power system. The accurate fault location can lighten the patrolling burden, and enhance the reliability of the power network. It adopts A/D which has high speed, and uses TMS320VC5402 DSP chip as the system core. This paper presented theory of operation based on traveling waves and achieved software and hardware in detail.

  19. Traveling Granular Segregation Patterns in a Long Drum Mixer

    OpenAIRE

    Choo, Kiam; Molteno, T. C. A.; Morris, Stephen W.

    1997-01-01

    Mixtures of granular media often exhibit size segregation along the axis of a partially-filled, horizontal, rotating cylinder. Previous experiments have observed axial bands of segregation that grow from concentration fluctuations and merge in a manner analogous to spinodal decomposition. We have observed that a new dynamical state precedes this effect in certain mixtures: bi-directional traveling waves. By preparing initial conditions, we found that the wave speed decreased with wavelength. ...

  20. Human Cortical Traveling Waves: Dynamical Properties and Correlations with Responses

    OpenAIRE

    Timothy M Patten; Christopher J Rennie; Robinson, Peter A.; Pulin Gong

    2012-01-01

    The spatiotemporal behavior of human EEG oscillations is investigated. Traveling waves in the alpha and theta ranges are found to be common in both prestimulus and poststimulus EEG activity. The dynamical properties of these waves, including their speeds, directions, and durations, are systematically characterized for the first time, and the results show that there are significant changes of prestimulus spontaneous waves in the presence of an external stimulus. Furthermore, the functional rel...

  1. Power convergence of Abel averages

    OpenAIRE

    Kozitsky, Yuri; Shoikhet, David; Zemanek, Jaroslav

    2012-01-01

    Necessary and sufficient conditions are presented for the Abel averages of discrete and strongly continuous semigroups, $T^k$ and $T_t$, to be power convergent in the operator norm in a complex Banach space. These results cover also the case where $T$ is unbounded and the corresponding Abel average is defined by means of the resolvent of $T$. They complement the classical results by Michael Lin establishing sufficient conditions for the corresponding convergence for a bounded $T$.

  2. High-speed rail-coming to America?

    Science.gov (United States)

    Cameron, David Ossian

    2009-01-01

    The United States lags many parts of the world when it comes to high-speed rail. But investing in high-speed rail could help us through current problems. Funds- $8 billion-in the economic stimulus package passed by Congress are designated for high-speed rail. Other funds in the pipeline total approximately $15.5 billion. High-speed rail can relieve congestion, free up national airspace, provide reliable transportation and positive economic development, create jobs, and is more energy efficient than other modes of travel. PMID:19608527

  3. A procedure for the inversion of f-mode travel times for solar flows

    OpenAIRE

    Jackiewicz, J.; Gizon, L.; Birch, A. C.; Thompson, M. J.

    2007-01-01

    We perform a two-dimensional inversion of f-mode travel times to determine near-surface solar flows. The inversion is based on optimally localized averaging of travel times. We use finite-wavelength travel-time sensitivity functions and a realistic model of the data errors. We find that it is possible to obtain a spatial resolution of 2 Mm. The error in the resulting flow estimate ultimately depends on the observation time and the number of travel distances used in the inversion.

  4. The Role of the Harmonic Vector Average in Motion Integration

    Directory of Open Access Journals (Sweden)

    Alan eJohnston

    2013-10-01

    Full Text Available The local speeds of object contours vary systematically with the cosine of the angle between the normal component of the local velocity and the global object motion direction. An array of Gabor elements whose speed changes with local spatial orientation in accordance with this pattern can appear to move as a single surface. The apparent direction of motion of plaids and Gabor arrays has variously been proposed to result from feature tracking, vector addition and vector averaging in addition to the geometrically correct global velocity as indicated by the intersection of constraints (IOC solution. Here a new combination rule, the harmonic vector average (HVA, is introduced, as well as a new algorithm for computing the IOC solution. The vector sum can be discounted as an integration strategy as it increases with the number of elements. The vector average over local vectors that vary in direction always provides an underestimate of the true global speed. The harmonic vector average however provides the correct global speed and direction for an unbiased sample of local velocities with respect to the global motion direction, as is the case for a simple closed contour. The HVA over biased samples provides an aggregate velocity estimate that can still be combined through an IOC computation to give an accurate estimate of the global velocity, which is not true of the vector average. Psychophysical results for type II Gabor arrays show perceived direction and speed falls close to the intersection of constraints direction for Gabor arrays having a wide range of orientations but the IOC prediction fails as the mean orientation shifts away from the global motion direction and the orientation range narrows. In this case perceived velocity generally defaults to the harmonic vector average.

  5. GH Travel & Mission Support System

    Data.gov (United States)

    US Agency for International Development — HTRAMS is a travel data collection system for GH that collects information on both the basic details of an employee's trips (destination, length, purpose, etc.) and...

  6. Mosquito Bite Prevention For Travelers

    Science.gov (United States)

    Mosquito Bite Prevention for Travelers Mosquitoes spread many types of viruses and parasites that can cause diseases ... be available. Protect yourself and your family from mosquito bites. Here’s how: Keep mosquitoes out of your ...

  7. PPL Travel & Mission Support System

    Data.gov (United States)

    US Agency for International Development — PTRAMS is a travel data collection system for PPL that collects information on both the basic details of an employee's trips (destination, length, purpose, etc.)...

  8. Tuberculosis Information for International Travelers

    Science.gov (United States)

    ... American Community Summit Background Slideset Children Correctional Facilities Homelessness International Travelers Pregnancy Health Disparities Laboratory Information Model Performance Evaluation Program (MPEP) Drug Susceptibility Testing The Uses of Nucleic Acid Amplification ...

  9. DCHA Travel & Mission Support System

    Data.gov (United States)

    US Agency for International Development — DTRAMS is a travel data collection system for DCHA that collects information on both the basic details of an employee's trips (destination, length, purpose, etc.)...

  10. Influenza Prevention: Information for Travelers

    Science.gov (United States)

    ... Medscape Podcasts Public Service Announcements (PSAs) Virus Images Influenza Types Seasonal Avian Swine Variant Pandemic Other Get ... this? Submit What's this? Submit Button Past Newsletters Influenza Prevention: Information for Travelers Language: English Español ...

  11. The effect of travel restrictions on the spread of a highly contagious disease in Sweden

    CERN Document Server

    Camitz, Martin

    2016-01-01

    Travel restrictions may reduce the spread of a contagious disease that threatens public health. In this study we investigate what effect different levels of travel restrictions may have on the speed and geographical spread of an outbreak of a disease similar to SARS. We use a stochastic simulation model of the Swedish population, calibrated with survey data of travel patterns between municipalities in Sweden collected over three years. We find that a ban on journeys longer than 50 km drastically reduces the speed and the geographical spread of outbreaks, even with when compliance is less than 100%. The result is found to be robust for different rates of inter-municipality transmission intensities. Travel restrictions may therefore be an effective way to mitigate the effect of a future outbreak.

  12. Elasticity of Long Distance Travelling

    OpenAIRE

    Knudsen, Mette Aagaard

    2011-01-01

    With data from the Danish expenditure survey for 12 years 1996 through 2007, this study analyses household expenditures for long distance travelling. Household expenditures are examined at two levels of aggregation having the general expenditures on transportation and leisure relative to five other aggregated commodities at the highest level, and the specific expenditures on plane tickets and travel packages at the lowest level. The Almost Ideal Demand System is applied to determine the relat...

  13. A model of multidestination travel

    DEFF Research Database (Denmark)

    Morisugi, H.; Tussyadiah, Iis; Kono, T.

    2006-01-01

    Because tourists derive utility from the enjoyment of destination characteristics, Lancaster's approach is putatively appropriate to address the particular structure of the tourism industry. Most research efforts regarding tourism destination, including those applying Lancaster's model, specifica...... explains that packages of multiple destinations can create preferable combinations of characteristics for certain travelers. Furthermore, the model provides useful strategies for tour operators in combining destinations into a travel menu or package. © 2006 Sage Publications....

  14. Sequentially pulsed traveling wave accelerator

    Science.gov (United States)

    Caporaso, George J.; Nelson, Scott D.; Poole, Brian R.

    2009-08-18

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  15. Ground-water travel time

    International Nuclear Information System (INIS)

    The Containment and Isolation Working Group considered issues related to the postclosure behavior of repositories in crystalline rock. This working group was further divided into subgroups to consider the progress since the 1978 GAIN Symposium and identify research needs in the individual areas of regional ground-water flow, ground-water travel time, fractional release, and cumulative release. The analysis and findings of the Ground-Water Travel Time Subgroup are presented

  16. Vocal attractiveness increases by averaging.

    Science.gov (United States)

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception.

  17. Vocal attractiveness increases by averaging.

    Science.gov (United States)

    Bruckert, Laetitia; Bestelmeyer, Patricia; Latinus, Marianne; Rouger, Julien; Charest, Ian; Rousselet, Guillaume A; Kawahara, Hideki; Belin, Pascal

    2010-01-26

    Vocal attractiveness has a profound influence on listeners-a bias known as the "what sounds beautiful is good" vocal attractiveness stereotype [1]-with tangible impact on a voice owner's success at mating, job applications, and/or elections. The prevailing view holds that attractive voices are those that signal desirable attributes in a potential mate [2-4]-e.g., lower pitch in male voices. However, this account does not explain our preferences in more general social contexts in which voices of both genders are evaluated. Here we show that averaging voices via auditory morphing [5] results in more attractive voices, irrespective of the speaker's or listener's gender. Moreover, we show that this phenomenon is largely explained by two independent by-products of averaging: a smoother voice texture (reduced aperiodicities) and a greater similarity in pitch and timbre with the average of all voices (reduced "distance to mean"). These results provide the first evidence for a phenomenon of vocal attractiveness increases by averaging, analogous to a well-established effect of facial averaging [6, 7]. They highlight prototype-based coding [8] as a central feature of voice perception, emphasizing the similarity in the mechanisms of face and voice perception. PMID:20129047

  18. Infectious Risks of Traveling Abroad.

    Science.gov (United States)

    Chen, Lin H; Blair, Barbra M

    2015-08-01

    A popular leisure activity, international travel can be associated with some infections. The most common travel-related illnesses appear to be gastrointestinal, dermatologic, respiratory, and systemic febrile syndromes. The pretravel medical consultation includes immunizations, malaria chemoprophylaxis, self-treatment for traveler's diarrhea, and advice on the prevention of a myriad of other infectious causes including dengue, chikungunya, rickettsiosis, leptospirosis, schistosomiasis, and strongyloidiasis. Travel to locations experiencing outbreaks such as Ebola virus disease, Middle East respiratory syndrome, avian influenza, and chikungunya call for specific alerts on preventive strategies. After travel, evaluation of an ill traveler must explore details of exposure, including destinations visited; activities; ingestion of contaminated food or drinks; contact with vectors, animals, fresh water, or blood and body fluids; and other potential exposures. Knowledge of the geographic distribution of infectious diseases is important in generating the differential diagnoses and testing accordingly. Empiric treatment is sometimes necessary when suspicion of a certain diagnosis is strong and confirmatory tests are delayed or lacking, particularly for infections that are rapidly progressive (for example, malaria) or for which timing of testing is prolonged (such as leptospirosis). PMID:26350325

  19. Nonlinear stability of periodic traveling wave solutions of systems of viscous conservation laws in the generic case

    Science.gov (United States)

    Johnson, Mathew A.; Zumbrun, Kevin

    Extending previous results of Oh-Zumbrun and Johnson-Zumbrun, we show that spectral stability implies linearized and nonlinear stability of spatially periodic traveling wave solutions of viscous systems of conservation laws for systems of generic type, removing a restrictive assumption that wave speed be constant to first order along the manifold of nearby periodic solutions. Key to our analysis is a nonlinear cancellation estimate observed by Johnson and Zumbrun, along with a detailed understanding of the Whitham averaged system. The latter motivates a careful analysis of the Bloch perturbation expansion near zero frequency and suggests factoring out an appropriate translational modulation of the underlying wave, allowing us to derive the sharpened low-frequency estimates needed to close the nonlinear iteration arguments.

  20. Sparsity Averaging for Compressive Imaging

    CERN Document Server

    Carrillo, Rafael E; Van De Ville, Dimitri; Thiran, Jean-Philippe; Wiaux, Yves

    2012-01-01

    We propose a novel regularization method for sparse image reconstruction from compressive measurements. The approach relies on the conjecture that natural images exhibit strong average sparsity over multiple coherent frames. The associated reconstruction algorithm, based on an analysis prior and a reweighted $\\ell_1$ scheme, is dubbed Sparsity Averaging Reweighted Analysis (SARA). We test our prior and the associated algorithm through extensive numerical simulations for spread spectrum and Gaussian acquisition schemes suggested by the recent theory of compressed sensing with coherent and redundant dictionaries. Our results show that average sparsity outperforms state-of-the-art priors that promote sparsity in a single orthonormal basis or redundant frame, or that promote gradient sparsity. We also illustrate the performance of SARA in the context of Fourier imaging, for particular applications in astronomy and medicine.

  1. Speed and structure of turbulent fronts in pipe flow

    CERN Document Server

    Song, Baofang; Hof, Björn; Avila, Marc

    2016-01-01

    The dynamics of laminar-turbulent fronts in pipe flow is investigated for Reynolds numbers between Re=1900 and Re=5500 using extensive direct numerical simulations. In this range the flow undergoes a continuous transition from localised puffs to weakly expanding and ultimately to strongly expanding turbulent slugs (Barkley et al. 2015). We here investigate the physical distinction between these two types of slug by analysing time-resolved statistics of their downstream fronts in the frame moving at the bulk turbulent advection speed. While weak fronts travel slower than the bulk turbulent advection speed, implying local relaminarisation, strong fronts travel faster and so feed on the laminar flow ahead. At Re$\\approx$2900 the downstream front speed becomes faster than the advection speed, marking the onset of strong fronts. We argue that large temporal fluctuations of production and dissipation at the laminar-turbulent interface drive the dynamical switches between the two types of front observed up to Re$\\si...

  2. Measures for speed management.

    NARCIS (Netherlands)

    2009-01-01

    Measures for speed management are essential for limiting the negative effects of driving too fast and at inappropriate speeds. To begin with, safe and credible speed limits need to be determined. Dynamic and variable speed limits that take into account the current circumstances, such as weather cond

  3. Integrated travel network model for studying epidemics: Interplay between journeys and epidemic

    OpenAIRE

    Ruan, Zhongyuan; Wang, Chaoqing; Ming Hui, Pak; Liu, Zonghua

    2015-01-01

    The ease of travelling between cities has contributed much to globalization. Yet, it poses a threat on epidemic outbreaks. It is of great importance for network science and health control to understand the impact of frequent journeys on epidemics. We stress that a new framework of modelling that takes a traveller’s viewpoint is needed. Such integrated travel network (ITN) model should incorporate the diversity among links as dictated by the distances between cities and different speeds of dif...

  4. Traveling waves for a nonlocal dispersal SIR model with standard incidence

    OpenAIRE

    LI*, Wan-Tong; Yang, Fei-Ying

    2014-01-01

    This paper is concerned with traveling wave solutions of a nonlocal dispersal SIR epidemic model with standard incidence. We show that our results on existence and nonexistence of traveling wave solutions are determined by the basic reproduction number of the corresponding ordinary differential model and the minimal wave speed. These threshold dynamics are proved by constructing an invariant cone and applying Schauder's fixed point theorem on this cone and the Laplace transform. The main diff...

  5. Application of the Expanded Theory of Planned Behavior in Intercity Travel Behavior

    OpenAIRE

    Jing Peng; Juan Zhi-cai; Gao Lin-jie

    2014-01-01

    Congestion in intercity corridors of metropolitan area has been increasing steadily. To alleviate congestion, many major investment projects, such as the high speed railway projects, were proposed by agency. To evaluate the adequacy and efficiency of these projects, the intercity travel behavior should be analyzed in metropolitan area. The paper constructed a Multiple Indicators and Multiple Causes (MIMIC) model according to an expanded theory of planned behavior (TPB) to study the travel beh...

  6. The Individual Travel Cost Method with Consumer-Specific Values of Travel Time Savings

    OpenAIRE

    Mikołaj Czajkowski; Marek Giergiczny; Jakub Kronenberg; Jeffrey Englin

    2015-01-01

    The treatment of the opportunity cost of travel time in travel cost models has been an area of research interest for many decades. This analysis develops a methodology to combine the travel distance and travel time data with respondent-specific estimates of the value of travel time savings. The individual travel time values are elicited with the use of discrete choice stated preference methods. The travel time valuation procedure is integrated into the valuation exercise to create a two equat...

  7. Inter-temporal variation in the travel time and travel cost parameters of transport models

    OpenAIRE

    Börjesson, Maria

    2012-01-01

    The parameters for travel time and travel cost are central in travel demand forecasting models. Since valuation of infrastructure investments requires prediction of travel demand for future evaluation years, inter-temporal variation of the travel time and travel cost parameters is a key issue in forecasting. Using two identical stated choice experiments conducted among Swedish drivers with an interval of 13 years, 1994 and 2007, this paper estimates the inter-temporal variation in travel time...

  8. Simulating hydroplaning of submarine landslides by quasi 3D depth averaged finite element method

    Science.gov (United States)

    De Blasio, Fabio; Battista Crosta, Giovanni

    2014-05-01

    G.B. Crosta, H. J. Chen, and F.V. De Blasio Dept. Of Earth and Environmental Sciences, Università degli Studi di Milano Bicocca, Milano, Italy Klohn Crippen Berger, Calgary, Canada Subaqueous debris flows/submarine landslides, both in the open ocean as well as in fresh waters, exhibit extremely high mobility, quantified by a ratio between vertical to horizontal displacement of the order 0.01 or even much less. It is possible to simulate subaqueous debris flows with small-scale experiments along a flume or a pool using a cohesive mixture of clay and sand. The results have shown a strong enhancement of runout and velocity compared to the case in which the same debris flow travels without water, and have indicated hydroplaning as a possible explanation (Mohrig et al. 1998). Hydroplaning is started when the snout of the debris flow travels sufficiently fast. This generates lift forces on the front of the debris flow exceeding the self-weight of the sediment, which so begins to travel detached from the bed, literally hovering instead of flowing. Clearly, the resistance to flow plummets because drag stress against water is much smaller than the shear strength of the material. The consequence is a dramatic increase of the debris flow speed and runout. Does the process occur also for subaqueous landslides and debris flows in the ocean, something twelve orders of magnitude larger than the experimental ones? Obviously, no experiment will ever be capable to replicate this size, one needs to rely on numerical simulations. Results extending a depth-integrated numerical model for debris flows (Imran et al., 2001) indicate that hydroplaning is possible (De Blasio et al., 2004), but more should be done especially with alternative numerical methodologies. In this work, finite element methods are used to simulate hydroplaning using the code MADflow (Chen, 2014) adopting a depth averaged solution. We ran some simulations on the small scale of the laboratory experiments, and secondly

  9. Urban Traffic Eco-Driving: Speed Advisory Tracking

    OpenAIRE

    De Nunzio, Giovanni; Canudas de Wit, Carlos; Moulin, Philippe

    2014-01-01

    International audience The evaluation of the benefits of an Eco-Driving assistance system is carried out in the urban environment in presence of traffic lights. The traffic evolution is modeled macroscopically with the Urban Variable-Length Model in a variable speed limits framework. Under the assumption of equal boundary flows, the vehicles in a road section dispose themselves according to well defined equilibrium conditions which are dependent on the traveling speed in the free-flow part...

  10. Travel Time Estimation and Prediction using Mobile Phones: A Cost Effective Method for Developing Countries

    Directory of Open Access Journals (Sweden)

    Satyakumar, M.

    2014-01-01

    Full Text Available Conventional data collection methods lack real time information and involve excessive cost of installation and maintenance. A real-time, low cost travel time data collection system can be developed using mobile phones. This project examines the use of mobile phones for travel time prediction of public transit vehicles and develops a dynamic travel time prediction model. Personnel were employed in public transit vehicles with mobile phones and these mobile phones were tracked continuously. Space information of the mobile phones represents the position of the buses and movement pattern of these mobile phones in turn represents the movement pattern of the public buses. The starting and arrival time at sections obtained from the cellular database were used to get the travel time and speed. Results obtained were statistically significant and it shows that use of mobile phone for travel time data collection is a low cost data collection technique for Indian cities.

  11. 28 CFR 2.93 - Travel approval.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Travel approval. 2.93 Section 2.93... Travel approval. (a) A parolee's Supervision Officer may approve travel outside the district of... possibilities. (3) Recurring travel across a district boundary, not to exceed fifty miles outside the...

  12. A relational approach to analysing leisure travel

    NARCIS (Netherlands)

    Ettema, D.F.; Schwanen, T.

    2012-01-01

    Leisure travel makes up a very significant part of daily travel and therefore needs to be considered in any travel demand management or general land use and transportation policy. Yet, research into leisure mobility has tended to ignore important aspects of leisure travel, such as its joint characte

  13. Advising pregnant women on miminising travel risks.

    Science.gov (United States)

    Tucker, Rosemary

    Pregnant women may face additional risks when travelling overseas, which must be considered with assessment and travel health advice before they decide to travel. A careful risk assessment should be completed to identify the key risks and strategies for staying safe while travelling. PMID:24772798

  14. 8 CFR 1244.15 - Travel abroad.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Travel abroad. 1244.15 Section 1244.15... REGULATIONS TEMPORARY PROTECTED STATUS FOR NATIONALS OF DESIGNATED STATES § 1244.15 Travel abroad. (a) After... Status shall not constitute permission to travel abroad. Permission to travel may be granted by...

  15. 49 CFR 230.76 - Piston travel.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Piston travel. 230.76 Section 230.76... Tenders Brake and Signal Equipment § 230.76 Piston travel. (a) Minimum piston travel. The minimum piston travel shall be sufficient to provide proper brake shoe clearance when the brakes are released....

  16. 8 CFR 244.15 - Travel abroad.

    Science.gov (United States)

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Travel abroad. 244.15 Section 244.15 Aliens... NATIONALS OF DESIGNATED STATES § 244.15 Travel abroad. (a) After the grant of Temporary Protected Status... to travel abroad. Permission to travel may be granted by the director pursuant to the...

  17. 38 CFR 21.7103 - Travel expenses.

    Science.gov (United States)

    2010-07-01

    ... Bill-Active Duty) Counseling § 21.7103 Travel expenses. (a) Travel for veterans and servicemembers. (1... 38 Pensions, Bonuses, and Veterans' Relief 2 2010-07-01 2010-07-01 false Travel expenses. 21.7103... travel to and from the place of counseling for individuals who are required to receive counseling if—...

  18. McKean caricature of the FitzHugh-Nagumo model: Traveling pulses in a discrete diffusive medium

    Science.gov (United States)

    Tonnelier, Arnaud

    2003-03-01

    This paper investigates traveling wave solutions of the spatially discrete reaction-diffusion systems whose kinetics are modeled by the McKean caricature of the FitzHugh-Nagumo model. In the limit of a weak coupling strength, we construct the traveling wave solutions and obtain the critical coupling constant below which propagation failure occurs. We report the existence of two different pulse traveling waves with different propagation speeds. Analytical results on the wave speed are obtained. Earlier results on propagation in the bistable medium are found as a limiting regime of our analysis.

  19. The value of travel time variance

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Engelson, Leonid

    2011-01-01

    This paper considers the value of travel time variability under scheduling preferences that are defined in terms of linearly time varying utility rates associated with being at the origin and at the destination. The main result is a simple expression for the value of travel time variability...... that does not depend on the shape of the travel time distribution. The related measure of travel time variability is the variance of travel time. These conclusions apply equally to travellers who can freely choose departure time and to travellers who use a scheduled service with fixed headway. Depending...... on parameters, travellers may be risk averse or risk seeking and the value of travel time may increase or decrease in the mean travel time....

  20. Snakes mimic earthworms: propulsion using rectilinear travelling waves.

    Science.gov (United States)

    Marvi, Hamidreza; Bridges, Jacob; Hu, David L

    2013-07-01

    In rectilinear locomotion, snakes propel themselves using unidirectional travelling waves of muscular contraction, in a style similar to earthworms. In this combined experimental and theoretical study, we film rectilinear locomotion of three species of snakes, including red-tailed boa constrictors, Dumeril's boas and Gaboon vipers. The kinematics of a snake's extension-contraction travelling wave are characterized by wave frequency, amplitude and speed. We find wave frequency increases with increasing body size, an opposite trend than that for legged animals. We predict body speed with 73-97% accuracy using a mathematical model of a one-dimensional n-linked crawler that uses friction as the dominant propulsive force. We apply our model to show snakes have optimal wave frequencies: higher values increase Froude number causing the snake to slip; smaller values decrease thrust and so body speed. Other choices of kinematic variables, such as wave amplitude, are suboptimal and appear to be limited by anatomical constraints. Our model also shows that local body lifting increases a snake's speed by 31 per cent, demonstrating that rectilinear locomotion benefits from vertical motion similar to walking. PMID:23635494

  1. Despeckling vs averaging of retinal UHROCT tomograms: advantages and limitations

    Science.gov (United States)

    Eichel, Justin A.; Lee, Donghyun D.; Wong, Alexander; Fieguth, Paul W.; Clausi, David A.; Bizheva, Kostadinka K.

    2011-03-01

    Imaging time can be reduced using despeckled tomograms, which have similar image metrics to those obtained by averaging several low speed tomograms or many high speed tomograms. Quantitative analysis was used to compare the performance of two speckle denoising approaches, algorithmic despeckling and frame averaging, as applied to retinal OCT images. Human retinal tomograms were acquired from healthy subjects with a research grade 1060nm spectral domain UHROCT system with 5μm axial resolution in the retina. Single cross-sectional retinal tomograms were processed with a novel speckle denoising algorithm and compared with frame averaged retinal images acquired at the same location. Image quality metrics such as the image SNR and contrast-to-noise ratio (CNR) were evaluated for both cases.

  2. Backpacker motivations: a travel career approach

    OpenAIRE

    Paris, Cody Morris; Teye, Victor

    2010-01-01

    The main purpose of this study was to conceptualize backpacker motivation within the framework of the Travel Career Pattern (TCP) theory of travel motivation. An online survey was administered to backpackers targeted in backpacker-specific online communities in order to obtain a diverse sample. First, underlying dimensions of backpacker motivation were identified. Second, backpackers were clustered into two groups based on travel experience and age: ‘high travel experience’ and ‘low travel ex...

  3. Travel related diseases and optimizing preventive strategies

    OpenAIRE

    R.W. Wieten

    2016-01-01

    With the figure of 1 billion annual travellers continuously increasing, travel is becoming more and more common. The binding element of this thesis is the aim to contribute to the improvement of pre-travel healthcare. The diseases studied either carry a high mortality (rabies, malaria, yellow fever) or morbidity (hepatitis A) rate. At the Academic Medical Center’s travel clinic, pre-travel guidelines were well adhered to. At Schiphol Airport (Amsterdam), we found that just over half of the VF...

  4. Network Structure and Travel Time Perception

    OpenAIRE

    Pavithra Parthasarathi; David Levinson; Hartwig Hochmair

    2013-01-01

    The purpose of this research is to test the systematic variation in the perception of travel time among travelers and relate the variation to the underlying street network structure. Travel survey data from the Twin Cities metropolitan area (which includes the cities of Minneapolis and St. Paul) is used for the analysis. Travelers are classified into two groups based on the ratio of perceived and estimated commute travel time. The measures of network structure are estimated using the street n...

  5. Additive measures of travel time variability

    OpenAIRE

    Engelson, Leonid; Fosgerau, Mogens

    2011-01-01

    This paper derives a measure of travel time variability for travellers equipped with scheduling preferences defined in terms of time-varying utility rates, and who choose departure time optimally. The corresponding value of travel time variability is a constant that depends only on preference parameters. The measure is unique in being additive with respect to independent parts of a trip. It has the variance of travel time as a special case. Extension is provided to the case of travellers who ...

  6. Observational Study of Travelers' Diarrhea.

    Science.gov (United States)

    Meuris

    1995-03-01

    Background: European air travelers returning from Algeria, Egypt, Mexico, Morocco, and Tunisia were interviewed about their experience of travelers' diseases upon arrival in Brussels. Diarrhea was mentioned by 37% of the adults and 27% of the children. These subjects were questioned about the types of measures taken, type and duration of drug treatment (if any), and about duration of diarrhea and side effects experienced. Methods: Final analysis was performed based on 2160 interviews. The largest proportion of diarrhea was reported in the age group 15-24 years (46%). Results: The majority of the 2160 subjects had opted for drug treatment (81%): 927 subjects for loperamide alone, 235 for loperamide in combination with nifuroxazide, and 178 for nifuroxazide alone. Other drugs had been used less frequently. The median time to recovery was 2.4 days with loperamide compared to 3.2 days with nifuroxazide and to 3.4 days for the no-treatment group. Conclusions: A stratification of the results by severity of the diarrhea suggests a rank of antidiarrheal potency as follows: loperamide > nifuroxazide > no-drug treatment. The side effect with the highest incidence was constipation (2.4% with loperamide). (J Travel Med 2:11-15, 1995) Travelers' diarrhea is usually defined as the passage of at least three unformed stools per day or any number of such stools when accompanied by fever, abdominal cramping, or vomiting. The definition may be broadened to include more trivial bowel disturbance.1,2 The duration of this self-limited disease generally is 3 to 5 days. Medical intervention aims at shortening the duration of disease, thus allowing the sufferer to resume his or her usual activities at an early stage. A shortened period of recovery to physical well-being has obvious favorable economic implications if the traveler is on business and may help the maintenance of a desired level of quality of life while a traveler is on holiday. An observational study of various medical

  7. Observational Study of Travelers' Diarrhea.

    Science.gov (United States)

    Meuris

    1995-03-01

    Background: European air travelers returning from Algeria, Egypt, Mexico, Morocco, and Tunisia were interviewed about their experience of travelers' diseases upon arrival in Brussels. Diarrhea was mentioned by 37% of the adults and 27% of the children. These subjects were questioned about the types of measures taken, type and duration of drug treatment (if any), and about duration of diarrhea and side effects experienced. Methods: Final analysis was performed based on 2160 interviews. The largest proportion of diarrhea was reported in the age group 15-24 years (46%). Results: The majority of the 2160 subjects had opted for drug treatment (81%): 927 subjects for loperamide alone, 235 for loperamide in combination with nifuroxazide, and 178 for nifuroxazide alone. Other drugs had been used less frequently. The median time to recovery was 2.4 days with loperamide compared to 3.2 days with nifuroxazide and to 3.4 days for the no-treatment group. Conclusions: A stratification of the results by severity of the diarrhea suggests a rank of antidiarrheal potency as follows: loperamide > nifuroxazide > no-drug treatment. The side effect with the highest incidence was constipation (2.4% with loperamide). (J Travel Med 2:11-15, 1995) Travelers' diarrhea is usually defined as the passage of at least three unformed stools per day or any number of such stools when accompanied by fever, abdominal cramping, or vomiting. The definition may be broadened to include more trivial bowel disturbance.1,2 The duration of this self-limited disease generally is 3 to 5 days. Medical intervention aims at shortening the duration of disease, thus allowing the sufferer to resume his or her usual activities at an early stage. A shortened period of recovery to physical well-being has obvious favorable economic implications if the traveler is on business and may help the maintenance of a desired level of quality of life while a traveler is on holiday. An observational study of various medical

  8. Improved road traffic emission inventories by adding mean speed distributions

    NARCIS (Netherlands)

    Smit, R.; Poelman, M.; Schrijver, J.

    2008-01-01

    Does consideration of average speed distributions on roads-as compared to single mean speed-lead to different results in emission modelling of large road networks? To address this question, a post-processing method is developed to predict mean speed distributions using available traffic data from a

  9. Poliomyelitis--prevention in travellers.

    Science.gov (United States)

    Mayer, Cora A; Neilson, Amy A

    2010-03-01

    This article is the second in a series providing a summary of prevention strategies and vaccination for infections that may be acquired by travellers. The series aims to provide practical strategies to assist general practitioners in giving travel advice, as a synthesis of multiple information sources which must otherwise be consulted. Poliomyelitis is a potentially fatal viral illness, which may cause acute flaccid paralysis and permanent central nervous system damage. Ongoing global efforts to eradicate poliomyelitis have been under way since 1988. Travellers are at risk of infection in countries with endemic wild poliomyelitis virus or imported cases, and can spread the infection to areas where poliomyelitis has been eradicated. While all adults should be immune to poliomyelitis, it is important that at-risk travellers are vaccinated appropriately. Vaccine options and regions currently reporting poliomyelitis are presented from a number of sources, which may facilitate the process of giving travel advice in a general practice setting, although it is also important to seek up-to-date epidemiological information.

  10. Health, sustainability and student travel.

    Science.gov (United States)

    Green, Gill; Morris, Jenny; Wade, Margaret

    2012-01-01

    A survey of 246 pre-registration nursing students in a University in the South West of England was carried out to explore the impact of course related travel on the student experience. Results from the survey indicated that students' main mode of transport to practice placements was by car which reflects the rural nature of the South West and the relative paucity of public transport. Long distances that many students travel to their study centre and to placements, and the concurrent financial strain that this creates, impacted negatively on the student experience. Students recognised the need to travel to a place of study and clinical placements and suggestions of minimising the negative impact of travel were offered. These included the increased use of electronic delivery of lectures, attendance at local university premises, the provision of shared transport to placements and placements closer to the student's home. Few students, however, considered the environmental impact of travel. Higher Education Institutions need to address issues of sustainability through promoting student wellbeing and taking steps to reduce greenhouse gas emissions. It is therefore important that student awareness of sustainability related issues is increased as well as focusing on reducing the environmental impact through organisational change. PMID:21664188

  11. Dependability in Aggregation by Averaging

    CERN Document Server

    Jesus, Paulo; Almeida, Paulo Sérgio

    2010-01-01

    Aggregation is an important building block of modern distributed applications, allowing the determination of meaningful properties (e.g. network size, total storage capacity, average load, majorities, etc.) that are used to direct the execution of the system. However, the majority of the existing aggregation algorithms exhibit relevant dependability issues, when prospecting their use in real application environments. In this paper, we reveal some dependability issues of aggregation algorithms based on iterative averaging techniques, giving some directions to solve them. This class of algorithms is considered robust (when compared to common tree-based approaches), being independent from the used routing topology and providing an aggregation result at all nodes. However, their robustness is strongly challenged and their correctness often compromised, when changing the assumptions of their working environment to more realistic ones. The correctness of this class of algorithms relies on the maintenance of a funda...

  12. Stochastic Approximation with Averaging Innovation

    CERN Document Server

    Laruelle, Sophie

    2010-01-01

    The aim of the paper is to establish a convergence theorem for multi-dimensional stochastic approximation in a setting with innovations satisfying some averaging properties and to study some applications. The averaging assumptions allow us to unify the framework where the innovations are generated (to solve problems from Numerical Probability) and the one with exogenous innovations (market data, output of "device" $e.g.$ an Euler scheme) with stationary or ergodic properties. We propose several fields of applications with random innovations or quasi-random numbers. In particular we provide in both setting a rule to tune the step of the algorithm. At last we illustrate our results on five examples notably in Finance.

  13. High average power supercontinuum sources

    Indian Academy of Sciences (India)

    J C Travers

    2010-11-01

    The physical mechanisms and basic experimental techniques for the creation of high average spectral power supercontinuum sources is briefly reviewed. We focus on the use of high-power ytterbium-doped fibre lasers as pump sources, and the use of highly nonlinear photonic crystal fibres as the nonlinear medium. The most common experimental arrangements are described, including both continuous wave fibre laser systems with over 100 W pump power, and picosecond mode-locked, master oscillator power fibre amplifier systems, with over 10 kW peak pump power. These systems can produce broadband supercontinua with over 50 and 1 mW/nm average spectral power, respectively. Techniques for numerical modelling of the supercontinuum sources are presented and used to illustrate some supercontinuum dynamics. Some recent experimental results are presented.

  14. Future Trends in Business Travel Decision Making

    Science.gov (United States)

    Mason, Keith J.

    2002-01-01

    This research surveys twenty large companies and their travellers to identify and evaluate the effects of pressures on the business travel market in the future. The influence of the following areas on the decision making process are addressed: (1) Corporate travel policies and increasing professionalism in corporate purchasing; (2) The development of global strategic airline alliances; (3) The emergence of low cost airlines on short haul markets; and (4) The development of internet based booking tools and travel agency IT. The survey shows differences in views between travel managers, and travellers with regard to corporate travel policies. While travel managers see policy rules, travellers interpret these as guidelines, indicating travel managers will need to take further actions to exercise true control of travel budgets. The data shows that companies are more likely to prescribe a class of airline ticket, than the choice of airline itself. Corporate hierarchical bias in travel policies is still common both for short and particularly long haul flying. Other findings show that while travel managers believe that their companies are likely to sign global deals with strategic airline groups within a five year period in a bid to consolidating spending, they also believe that nearly a third of short haul flying will be taken with low cost carriers, indicating further penetration in this business travel market by these carriers. The paper also provides other predictions about the business travel market, based on the survey findings.

  15. Existence and qualitative properties of travelling waves for an epidemiological model with mutations

    Science.gov (United States)

    Griette, Quentin; Raoul, Gaël

    2016-05-01

    In this article, we are interested in a non-monotonic system of logistic reaction-diffusion equations. This system of equations models an epidemic where two types of pathogens are competing, and a mutation can change one type into the other with a certain rate. We show the existence of travelling waves with minimal speed, which are usually non-monotonic. Then we provide a description of the shape of those constructed travelling waves, and relate them to some Fisher-KPP fronts with non-minimal speed.

  16. Measurement of the Speed of Sound in a Metal Rod.

    Science.gov (United States)

    Mak, Se-yuen; Ng, Yee-kong; Wu, Kam-wah

    2000-01-01

    Suggests two improved methods to measure the speed of sound in a metal rod. One employs a fast timer to measure the time required for a compression pulse to travel along the rod from end to end, and a second uses a microphone to measure the frequency of the fundamental mode of a freely suspending singing rod. (Author/ASK)

  17. Travelling wave analysis of a mathematical model of glioblastoma growth.

    Science.gov (United States)

    Gerlee, Philip; Nelander, Sven

    2016-06-01

    In this paper we analyse a previously proposed cell-based model of glioblastoma (brain tumour) growth, which is based on the assumption that the cancer cells switch phenotypes between a proliferative and motile state (Gerlee and Nelander, 2012). The dynamics of this model can be described by a system of partial differential equations, which exhibits travelling wave solutions whose wave speed depends crucially on the rates of phenotypic switching. We show that under certain conditions on the model parameters, a closed form expression of the wave speed can be obtained, and using singular perturbation methods we also derive an approximate expression of the wave front shape. These new analytical results agree with simulations of the cell-based model, and importantly show that the inverse relationship between wave front steepness and speed observed for the Fisher equation no longer holds when phenotypic switching is considered. PMID:27021919

  18. Travelling wave analysis of a mathematical model of glioblastoma growth.

    Science.gov (United States)

    Gerlee, Philip; Nelander, Sven

    2016-06-01

    In this paper we analyse a previously proposed cell-based model of glioblastoma (brain tumour) growth, which is based on the assumption that the cancer cells switch phenotypes between a proliferative and motile state (Gerlee and Nelander, 2012). The dynamics of this model can be described by a system of partial differential equations, which exhibits travelling wave solutions whose wave speed depends crucially on the rates of phenotypic switching. We show that under certain conditions on the model parameters, a closed form expression of the wave speed can be obtained, and using singular perturbation methods we also derive an approximate expression of the wave front shape. These new analytical results agree with simulations of the cell-based model, and importantly show that the inverse relationship between wave front steepness and speed observed for the Fisher equation no longer holds when phenotypic switching is considered.

  19. Fundamental Travel Demand Model Example

    Science.gov (United States)

    Hanssen, Joel

    2010-01-01

    Instances of transportation models are abundant and detailed "how to" instruction is available in the form of transportation software help documentation. The purpose of this paper is to look at the fundamental inputs required to build a transportation model by developing an example passenger travel demand model. The example model reduces the scale to a manageable size for the purpose of illustrating the data collection and analysis required before the first step of the model begins. This aspect of the model development would not reasonably be discussed in software help documentation (it is assumed the model developer comes prepared). Recommendations are derived from the example passenger travel demand model to suggest future work regarding the data collection and analysis required for a freight travel demand model.

  20. Travel epidemiology: the Saudi perspective.

    Science.gov (United States)

    Memish, Ziad A; Venkatesh, S; Ahmed, Qanta A

    2003-02-01

    The Kingdom of Saudi Arabia occupies four-fifths of the Arabian Peninsula, with a land area of 2 million square kilometres. Saudi Arabia holds a unique position in the Islamic world, as the custodian of the two holiest places of Islam, in Mecca and Medina. Annually, some 2 million Muslims from over 140 countries embark on Hajj. This extraordinary en masse migration is a unique forum for the study of travel epidemiology since the Hajj carries various health risks, both communicable and non-communicable, often on a colossal scale. Non-communicable hazards of the Hajj include stampede and motor vehicle trauma, fire-related burn injuries and accidental hand injury during animal slaughter. Communicable hazards in the form of outbreaks of multiple infectious diseases have been reported repeatedly, during and following the Hajj. Meningococcal meningitis, gastroenteritis, hepatitis A, B and C, and various zoonotic diseases comprise some of the possible infectious hazards at the Hajj. Many of these infectious and non-infectious hazards can be avoided or averted by adopting appropriate prophylactic measures. Physicians and health personnel must be aware of these risks to appropriately educate, immunize and prepare these travellers facing the unique epidemiological challenges of Hajj in an effort to minimize untoward effects. Travel epidemiology related to the Hajj is a new and exciting area, which offers valuable insights to the travel specialist. The sheer scale of numbers affords a rare view of migration medicine in action. As data is continually gathered and both national and international policy making is tailored to vital insights gained through travel epidemiology, the Hajj will be continually safeguarded. Practitioners will gain from findings of travel related epidemiological changes in evolution at the Hajj: the impact of vaccinating policies, infection control policies and public health are afforded a real-world laboratory setting at each annual Hajj, allowing us to

  1. 城市快速路可变限速策略%Variable Speed Limits Strategy of Urban Expressway

    Institute of Scientific and Technical Information of China (English)

    孙静怡; 沈俊江; 刘拥华; 陈蜀乔

    2012-01-01

    对城市快速路可变限速控制策略的理论基础进行了研究.在对快速路上的主线车速、进出口匝道车速、分流点合流点车速的特性及速度分布特性进行深入分析的基础上,建立了快速路主线车速-密度动态关系模型,提出考虑出口匝道、不良天气以及道路线形因素下基于安全性的3种主线车速的约束条件.利用积分调节器建立了入口匝道控制模型;提出了基于道路服务流量、行程时间、入口匝道平均等待时间以及行程时间延误4种可变限速的目标函数,利用4种目标函数的线性组合建立了3种系统最优问题,即:低密度状态下路段通行能力最大,行程时间最短;中密度状态下路段通行能力最大,入口匝道平均等待时间最短;以及高密度状态下入口匝道平均等待时间最短,主线车流行程时间延误最短.利用VISSIM仿真模拟手段对可变限速控制模型进行分析,得到可变限速控制策略下与未采取控制策略下的交通流参数结果,验证了可变限速控制策略的有效性.%The theory of variable speed limit control strategy for urban expressway was researched. Based on analysing different characteristics of speeds at mainline, entrance and exit ramps, diverge and merge of urban expressway, the model of dynamic relation between traffic speed and density of expressway mainline was set up, and the safety based constraint condition of mainline speed considering exit ramp, bad weather and road alignment was put forward. The entrance ramp control model was established by using integral regulator. Four variable speed limit target functions based on road service traffic volume, travel time, average waiting time at entrance ramp, and travel time delay were put forward. By using the linear combination of the four objective functions, three kinds of system optimal objective were established. The first is the largest capacity and the shortest travel time in low

  2. Short-Term Speed Prediction Using Remote Microwave Sensor Data: Machine Learning versus Statistical Model

    Directory of Open Access Journals (Sweden)

    Han Jiang

    2016-01-01

    Full Text Available Recently, a number of short-term speed prediction approaches have been developed, in which most algorithms are based on machine learning and statistical theory. This paper examined the multistep ahead prediction performance of eight different models using the 2-minute travel speed data collected from three Remote Traffic Microwave Sensors located on a southbound segment of 4th ring road in Beijing City. Specifically, we consider five machine learning methods: Back Propagation Neural Network (BPNN, nonlinear autoregressive model with exogenous inputs neural network (NARXNN, support vector machine with radial basis function as kernel function (SVM-RBF, Support Vector Machine with Linear Function (SVM-LIN, and Multilinear Regression (MLR as candidate. Three statistical models are also selected: Autoregressive Integrated Moving Average (ARIMA, Vector Autoregression (VAR, and Space-Time (ST model. From the prediction results, we find the following meaningful results: (1 the prediction accuracy of speed deteriorates as the prediction time steps increase for all models; (2 the BPNN, NARXNN, and SVM-RBF can clearly outperform two traditional statistical models: ARIMA and VAR; (3 the prediction performance of ANN is superior to that of SVM and MLR; (4 as time step increases, the ST model can consistently provide the lowest MAE comparing with ARIMA and VAR.

  3. Maximizing the spreading speed of KPP fronts in two-dimensional stratified media

    CERN Document Server

    Liang, Xing; Matano, Hiroshi

    2010-01-01

    We consider the equation $u_t=u_{xx}+u_{yy}+b(x)f(u)+g(u)$, $(x,y)\\in\\mathbb R^2$ with monostable nonliearity, where $b(x)$ is a nonnegative measure on $\\mathbb R$ that is periodic in $x.$ In the case where $b(x)$ is a smooth periodic function, there exists a pulsating travelling wave that propagates in the direction $(\\cos\\theta,\\sin\\theta)$ -- with average speed $c$ if and only if $c\\geq c^*(\\theta,b),$ where $c^*(\\theta,b)$ is a certain positive number depending on $b.$ Moreover, the quantity $w(\\theta;{b})=\\min_{|\\theta-\\phi|<\\frac{\\pi}{2}}c^*(\\phi;{b})/\\cos(\\theta-\\phi)$ is called the spreading speed. This theory can be extended by showing the existence of the minimal speed $c^*(\\theta,b)$ for any nonnegative measure $b$ with period $L.$ We then study the question of maximizing $c^*(\\theta,b)$ under the constraint $\\int_{[0,L)}b(x)dx=\\alpha L,$ where $\\alpha$ is an arbitrarily given positive constant. We prove that the maximum is attained by periodically arrayed Dirac's delta functions $h(x)=\\alpha L\\...

  4. Value of travel time savings

    DEFF Research Database (Denmark)

    Le Masurier, P.; Polak, J.; Pawlak, Janet;

    2015-01-01

    A team of specialist market researchers and Value of Time experts comprising members from SYSTRA, Imperial College London and the Technical University of Denmark has conducted a formal audit and peer review of research undertaken by Arup/ITS Leeds/Accent to derive Value of Travel Time Savings...... Preference (RP) models that were used to derive final Values of Travel Time (VTT). This report contains the findings of our audit and peer review of the procedures adopted by the research team during data collection of the three surveys (SP, RP and Employers Surveys); a peer review of the reported approach...

  5. [Pulmonary diseases among returning travelers].

    Science.gov (United States)

    Barras, G; Michel, Y; Wagner, N; Loutan, L

    2012-05-01

    Respiratory tract infections are a frequent cause of travelers' health problems. Tropical diseases are relatively rare compared to common respiratory infections. Nevertheless, due to their potential gravity, they must be systematically considered. The differential diagnosis of tropical pathogens is wide. A targeted travel history taking into account specific epidemiological, geographical and behavioral risk factors helps focusing biological exams to identify the causative diagnosis. The chest radiography remains very helpful in this context; however, more specific exams, such as serologies are often necessary to reach a final diagnosis. PMID:22662629

  6. Traveling-Wave Membrane Photomixers

    Science.gov (United States)

    Wyss, R. A.; Martin, S. C.; Nakamura, B. J.; Neto, A.; Pasqualini, D.; Siegel, P. H.; Kadow, C.; Gossard, A. C.

    2001-01-01

    Traveling-wave photomixers have superior performance when compared with lumped area photomixers in the 1 to 3 THz frequency range. Their large active area and distributed gain mechanism assure high thermal damage threshold and elimination of the capacitive frequency roll-off. However, the losses experienced by the radio frequency wave traveling along the coplanar strips waveguide (due to underlying semi-infinite GaAs substrate) were a serious drawback. In this paper we present device designs and an experimental setup that make possible the realization of photomixers on membranes which eliminate the losses.

  7. Rabies and Risk to Travelers

    Centers for Disease Control (CDC) Podcasts

    2007-10-01

    Each year over 55,000 people die because of rabies, mostly from being bitten by rabid dogs. Over half of all rabies infections occur in children under the age of 15 who live in developing countries, but travelers are not immune. This podcast discusses some of the activities that put travelers at risk for rabies and describes ways to prevent infection.  Created: 10/1/2007 by National Center for the Prevention, Detection and Control of Infectious Diseases (NCPDCID).   Date Released: 10/5/2007.

  8. Danish travel activities: do we travel more and longer – and to what extent?

    DEFF Research Database (Denmark)

    Knudsen, Mette Aagaard

    Two separate Danish National travel surveys are analysed to outline the amount and extent of national and international travelling during the latest 15-20 years; the national travel survey (TU) describes mainly national daily travel activities, whereas the holiday and business travel survey...... describes national and international travel activities including overnight stay(s). When sampling only respondents with trips above 100 kilometres, they only accounts for around 2% of all daily travel activities, however, this share appears to increase and suggest in general that we do travel longer...... holidays. The majority of international travel is within Europe, but increasing travelling outside Europe is furthermore emerging. In total these trends implies that Danes do travel more and longer, which is related to a general increase in travelling within the whole population, but also more holidays per...

  9. Diffusive behavior of a greedy traveling salesman

    Science.gov (United States)

    Lipowski, Adam; Lipowska, Dorota

    2011-06-01

    Using Monte Carlo simulations we examine the diffusive properties of the greedy algorithm in the d-dimensional traveling salesman problem. Our results show that for d=3 and 4 the average squared distance from the origin is proportional to the number of steps t. In the d=2 case such a scaling is modified with some logarithmic corrections, which might suggest that d=2 is the critical dimension of the problem. The distribution of lengths also shows marked differences between d=2 and d>2 versions. A simple strategy adopted by the salesman might resemble strategies chosen by some foraging and hunting animals, for which anomalous diffusive behavior has recently been reported and interpreted in terms of Lévy flights. Our results suggest that broad and Lévy-like distributions in such systems might appear due to dimension-dependent properties of a search space.

  10. Michel Parameters averages and interpretation

    International Nuclear Information System (INIS)

    The new measurements of Michel parameters in τ decays are combined to world averages. From these measurements model independent limits on non-standard model couplings are derived and interpretations in the framework of specific models are given. A lower limit of 2.5 tan β GeV on the mass of a charged Higgs boson in models with two Higgs doublets can be set and a 229 GeV limit on a right-handed W-boson in left-right symmetric models (95 % c.l.)

  11. Mind your travel ! Motivation, time use, and intent : Three factors of travel to be investigated

    OpenAIRE

    PAPON, Francis; Meissonnier, Joël

    2013-01-01

    The objective is to investigate the drivers of travel demand beyond the need to travel to destination; travellers may engage a trip for the sake of it, at least to some extent: travel includes a share of 'primary utility'. The paper focuses on two types of data and analysis: the primary utility of travel questions passed in the last French national travel survey, and eight dimensions of a trip proposed from a sociological analysis. The paper mixes these approaches and correlate survey answers...

  12. Preparing patients to travel abroad safely. Part 1: Taking a travel history and identifying special risks.

    OpenAIRE

    Thomas, R E

    2000-01-01

    OBJECTIVE: To present for family physicians without access to a travel clinic and the Internet the questions to ask about the medical history and itinerary of their patients traveling abroad. To suggest ways to identify and advise high-risk patients. QUALITY OF EVIDENCE: MEDLINE searches from 1990 to November 1998 located 51 articles on travel and diabetes, 37 on travel and chronic obstructive pulmonary disease (COPD), 63 on travel and heart disease, 192 on travel and pregnancy, and 298 on tr...

  13. Tradeoffs between time allocations to maintenance activities/travel and discretionary activities/travel

    OpenAIRE

    Chen, Cynthia Q; Mokhtarian, Patricia L

    2006-01-01

    This paper focuses on the tradeoff in time allocation between maintenance activities/travel and discretionary activities/travel. We recognize that people generally must travel a minimum amount of time in order to allocate one unit of time to the activity. This minimum amount of travel is represented by the travel time price, a ratio obtained by dividing the total amount of time traveling to maintenance or discretionary activities by the total amount of time spent on activities of the same typ...

  14. Effect of Rainfall on Travel Time and Accuracy of Travel Time prediction with rainfall

    OpenAIRE

    Chung, E; EL-FAOUZI, NE; Kuwahara, M

    2007-01-01

    Travel time is an important parameter to report to travelers. From the user's perspective, accurate predictions and an estimate of their precision are more beneficial than the current travel time since conditions may change significantly before a traveler completes the journey. Past researches have developed travel time prediction models without considering accidents and rain. Normally accident and Rain may cause to increase travel time. Therefore, it may be interesting to consider Rain and a...

  15. Contact Frequency, Travel Time, and Travel Costs for Patients with Rheumatoid Arthritis

    OpenAIRE

    Jan Sørensen; Louise Linde; Merete Lund Hetland

    2014-01-01

    Objectives. To investigate travel time, and travel cost related to contacts with health care providers for patients with rheumatoid arthritis (RA) during a three-month period. Methods. Patient-reported travel time and travel cost were obtained from 2847 patients with RA. Eleven outpatient clinics across Denmark recruited patients to the study. Data collected included frequency, travel time and travel costs for contacts at rheumatology outpatient clinics, other outpatient clinics, general prac...

  16. Time-distance helioseismology: A new averaging scheme for measuring flow vorticity

    CERN Document Server

    Langfellner, Jan; Birch, Aaron C

    2014-01-01

    Time-distance helioseismology provides information about vector flows in the near-surface layers of the Sun by measuring wave travel times between points on the solar surface. Specific spatial averages of travel times have been proposed for distinguishing between flows in the east-west and north-south directions and measuring the horizontal divergence of the flows. No specific measurement technique has, however, been developed to measure flow vorticity. Here we propose a new measurement technique tailored to measuring the vertical component of vorticity. Fluid vorticity is a fundamental property of solar convection zone dynamics and of rotating turbulent convection in particular. The method consists of measuring the travel time of waves along a closed contour on the solar surface in order to approximate the circulation of the flow along this contour. Vertical vorticity is related to the difference between clockwise and counter-clockwise travel times. We applied the method to characterize the vortical motions ...

  17. The cost-constrained traveling salesman problem

    Energy Technology Data Exchange (ETDEWEB)

    Sokkappa, P.R.

    1990-10-01

    The Cost-Constrained Traveling Salesman Problem (CCTSP) is a variant of the well-known Traveling Salesman Problem (TSP). In the TSP, the goal is to find a tour of a given set of cities such that the total cost of the tour is minimized. In the CCTSP, each city is given a value, and a fixed cost-constraint is specified. The objective is to find a subtour of the cities that achieves maximum value without exceeding the cost-constraint. Thus, unlike the TSP, the CCTSP requires both selection and sequencing. As a consequence, most results for the TSP cannot be extended to the CCTSP. We show that the CCTSP is NP-hard and that no K-approximation algorithm or fully polynomial approximation scheme exists, unless P = NP. We also show that several special cases are polynomially solvable. Algorithms for the CCTSP, which outperform previous methods, are developed in three areas: upper bounding methods, exact algorithms, and heuristics. We found that a bounding strategy based on the knapsack problem performs better, both in speed and in the quality of the bounds, than methods based on the assignment problem. Likewise, we found that a branch-and-bound approach using the knapsack bound was superior to a method based on a common branch-and-bound method for the TSP. In our study of heuristic algorithms, we found that, when selecting modes for inclusion in the subtour, it is important to consider the neighborhood'' of the nodes. A node with low value that brings the subtour near many other nodes may be more desirable than an isolated node of high value. We found two types of repetition to be desirable: repetitions based on randomization in the subtour buildings process, and repetitions encouraging the inclusion of different subsets of the nodes. By varying the number and type of repetitions, we can adjust the computation time required by our method to obtain algorithms that outperform previous methods.

  18. Supersonic stall flutter of high-speed fans

    Science.gov (United States)

    Adamczyk, J. J.; Stevans, W.; Jutras, R.

    1981-01-01

    An analytical model is proposed for predicting the onset of supersonic stall bending flutter in high-speed rotors. The analysis is based on a modified two-dimensional, compressible, unsteady actuator disk theory. The stability boundary predicted by the analysis is shown to be in good agreement with the measured boundary of a high speed fan. The prediction that the flutter mode would be a forward traveling wave sensitive to wheel speed and aerodynamic loading is confirmed by experimental measurements. In addition, the analysis shows that reduced frequency and dynamic head also play a significant role in establishing the supersonic stall bending flutter boundary of an unshrouded fan.

  19. The elite weightlifter's strength and speed qualities

    Directory of Open Access Journals (Sweden)

    Yukhno Y.O.

    2010-01-01

    Full Text Available The problems of estimation of power and speed possibilities of skilled weightlifter's are considered. In an experiment used complex REV 9000. The method of biomechanics control is developed. It allows in optimum terms to estimate the level of development of separate biolinks of body of sportsman. Speed power possibilities of right extensor higher on the average on 13%. Razgibatel' has large readiness to active reduction in the conditions of considerable tensions.

  20. The value of travel time variance

    OpenAIRE

    Fosgerau, Mogens; Engelson, Leonid

    2010-01-01

    This paper considers the value of travel time variability under scheduling preferences that are de�fined in terms of linearly time-varying utility rates associated with being at the origin and at the destination. The main result is a simple expression for the value of travel time variability that does not depend on the shape of the travel time distribution. The related measure of travel time variability is the variance of travel time. These conclusions apply equally to travellers who can free...

  1. Time Travel in the Library

    Science.gov (United States)

    Brown, Donna W.

    2005-01-01

    A Time Travel project in the library gives enthusiasm to students to connect with the past and reinforces their research skills while instilling respect for the past years. The librarian should choose one specific decade to highlight in the library and create an extravaganza that would allow memorabilia from that time period to be located without…

  2. Travel to the Rio Olympics

    Centers for Disease Control (CDC) Podcasts

    2016-07-21

    Learn how to stay healthy and safe when travelling to the 2016 Olympic Games in Rio de Janeiro.  Created: 7/21/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 7/21/2016.

  3. Statistical Complexity in Traveling Densities

    OpenAIRE

    Lopez-Ruiz, Ricardo; Sanudo, Jaime

    2009-01-01

    In this work, we analyze the behavior of statistical complexity in several systems where two identical densities that travel in opposite direction cross each other. The crossing between two Gaussian, rectangular and triangular densities is studied in detail. For these three cases, the shape of the total density presenting an extreme value in complexity is found.

  4. On Labeled Traveling Salesman Problems

    DEFF Research Database (Denmark)

    Couetoux, Basile; Gourves, Laurent; Monnot, Jerome;

    2008-01-01

    We consider labeled Traveling Salesman Problems, defined upon a complete graph of n vertices with colored edges. The objective is to find a tour of maximum (or minimum) number of colors. We derive results regarding hardness of approximation, and analyze approximation algorithms for both versions...

  5. Communication from Carlson Wagonlit Travel

    CERN Multimedia

    2009-01-01

    We are pleased to inform our customers that the range of tourist guides and roadmaps on sale in our offices has now been extended. We aim to help you prepare your upcoming holiday or business trip in any way we can. Please do not hesitate to contact us should you need any further information. The team at CARLSON WAGONLIT TRAVEL

  6. Economic Downturn Limits Conference Travel

    Science.gov (United States)

    Young, Jeffrey R.

    2009-01-01

    Attendance is down at many academic and professional conferences in higher education this year, and next year's numbers are expected to be far worse, as campus budgets take further beatings. With many colleges limiting travel to professors or administrators who are speaking at events they are attending, will anyone be left in the audience? A new…

  7. CITM: Asian's Largest Travel Show

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Jointly hosted by China National Tourism Administration, Yunnan Provincial People's Government and General Administration of Civil Aviation of China, China International Travel Mart (CITM) is a major step to develop inbound tourism, to increase tourism receipts in foreign exchanges, and to enhance the international status of China's tourism industry.

  8. Your Travel Dollar. Money Management.

    Science.gov (United States)

    Baran, Nancy H., Ed.

    This illustrated guide was designed to familiarize consumers with planning a vacation trip, whether domestic or abroad. The guide covers setting up a budget; package tours; cruises and charter flights; travel agencies and clubs; and arranging stays in hotels/motels, rental condominiums, bed-and-breakfasts, hostels, campsites, and private…

  9. The hazards of space travel

    OpenAIRE

    Setlow, Richard B.

    2003-01-01

    Before sending out astronauts on an interplanetary mission, we need to investigate how the conditions in space affect human health. The International Space Station is therefore of huge importance to ensure the health of a spaceship crew travelling to other planets

  10. Sooty Shearwater - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  11. Northern Fulmar - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  12. Wilson's Storm Petrel - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  13. Herring Gull - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  14. Common Tern - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  15. Leach's Storm Petrel - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  16. Pomarine Jaeger - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  17. Common Eider - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  18. Common Loon - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  19. Roseate Tern - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  20. Laughing Gull - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  1. Great Shearwater - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  2. Red Phalarope - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  3. Surf Scoter - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  4. Bonaparte's Gull - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  5. Northern Gannet - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  6. Cory's Shearwater - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  7. Black Scoter - Avian Average Annual Abundance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data represent predicted number of individuals of each listed seabird species per standardized survey segment (15 minute travel time at 10 knots = approx. 2.5...

  8. Radiation Risk Projections for Space Travel

    Science.gov (United States)

    Cucinotta, Francis

    2003-01-01

    Space travelers are exposed to solar and galactic cosmic rays comprised of protons and heavy ions moving with velocities close to the speed of light. Cosmic ray heavy ions are known to produce more severe types of biomolecular damage in comparison to terrestrial forms of radiation, however the relationship between such damage and disease has not been fully elucidated. On Earth, we are protected from cosmic rays by atmospheric and magnetic shielding, and only the remnants of cosmic rays in the form of ground level muons and other secondary radiations are present. Because human epidemiology data is lacking for cosmic rays, risk projection must rely on theoretical understanding and data from experimental models exposed to space radiation using charged particle accelerators to simulate space radiation. Although the risks of cancer and other late effects from cosmic rays are currently believed to present a severe challenge to space travel, this challenge is centered on our lack of confidence in risk projections methodologies. We review biophysics and radiobiology data on the effects of the cosmic ray heavy ions, and the current methods used to project radiation risks . Cancer risk projections are described as a product of many biological and physical factors, each of which has a differential range of uncertainty due to lack of data and knowledge. Risk projections for space travel are described using Monte-Carlo sampling from subjective error di stributions that represent the lack of knowledge in each factor that contributes to the projection model in order to quantify the overall uncertainty in risk projections. This analysis is applied to space mi ssion scenarios including lunar colony, deep space outpost, and a Mars mission. Results suggest that the number of days in space where cancer mortality risks can be assured at a 95% confidence level to be below the maximum acceptable risk for radi ation workers on Earth or the International Space Station is only on the order

  9. Danish long distance travel A study of Danish travel behaviour and the role of infrequent travel activities

    DEFF Research Database (Denmark)

    Knudsen, Mette Aagaard

    2014-01-01

    ), the TU overnight survey, and the Danish Tourism Statistics from the Business and Holiday Survey (HBS). This has enabled focus on infrequent travel activities segmented relative to travel purpose, distance threshold, or travelling with overnight stays. At an overall level the thesis has three main...... travel represents more than 60% of all travelled kilometres by individuals, and almost 25% alone stem from international holiday tourism even though international holiday travels represent only 0.1% of all travel activities. The study of holiday tourism has outlined some apparent trends that are of high...... in part II. The first paper outlines and exemplifies the presence and magnitude of different survey biases in the Danish National Travel Survey (TU). The study finds that response biases are heterogeneously distributed across the population and that the bias leads to significant overestimation of car...

  10. Flexible time domain averaging technique

    Science.gov (United States)

    Zhao, Ming; Lin, Jing; Lei, Yaguo; Wang, Xiufeng

    2013-09-01

    Time domain averaging(TDA) is essentially a comb filter, it cannot extract the specified harmonics which may be caused by some faults, such as gear eccentric. Meanwhile, TDA always suffers from period cutting error(PCE) to different extent. Several improved TDA methods have been proposed, however they cannot completely eliminate the waveform reconstruction error caused by PCE. In order to overcome the shortcomings of conventional methods, a flexible time domain averaging(FTDA) technique is established, which adapts to the analyzed signal through adjusting each harmonic of the comb filter. In this technique, the explicit form of FTDA is first constructed by frequency domain sampling. Subsequently, chirp Z-transform(CZT) is employed in the algorithm of FTDA, which can improve the calculating efficiency significantly. Since the signal is reconstructed in the continuous time domain, there is no PCE in the FTDA. To validate the effectiveness of FTDA in the signal de-noising, interpolation and harmonic reconstruction, a simulated multi-components periodic signal that corrupted by noise is processed by FTDA. The simulation results show that the FTDA is capable of recovering the periodic components from the background noise effectively. Moreover, it can improve the signal-to-noise ratio by 7.9 dB compared with conventional ones. Experiments are also carried out on gearbox test rigs with chipped tooth and eccentricity gear, respectively. It is shown that the FTDA can identify the direction and severity of the eccentricity gear, and further enhances the amplitudes of impulses by 35%. The proposed technique not only solves the problem of PCE, but also provides a useful tool for the fault symptom extraction of rotating machinery.

  11. Vehicle routing problem with time-varying speed

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-zhong

    2010-01-01

    Vehicle routing problem with time-varying speed(VRPTS)is a generalization of vehicle routing problem in which the travel speed between two locations depends on the passing areas and the time of a day.This paper proposes a simple model for estimating time-varying travel speeds in VRPTS that relieves much bur den to the data-related problems.The study further presents three heuristics(saving technique,proximity priority searching technique,and insertion technique)for VRPTS,developed by extending and modifying the existing heuristics for conventional VRP.The results of computational experiments demonstrate that the proposed estimation model performs well and the saving technique is the best among the three heuristics.

  12. Ways to Maximize Public Revenues from Travel Industry

    OpenAIRE

    Tetyana Tomnyuk

    2015-01-01

    The article is devoted to identification of the ways to increase public revenues from travel industry. The factors are defined which determine formation of national income from tourism. Individual trends of tourism in Ukraine are analyzed. The rating of Ukraine is set among European countries in number of foreign visitors. Average index of expenses is defined per one foreigner in the ten countries of Europe mostly visited by tourists. Availability of spare reserves is grounded for tourist pot...

  13. On the relationship between travel time and travel distance of commuters Reported versus network travel data in the Netherlands

    OpenAIRE

    Rietveld, P.; Zwart, B.; Wee, van der, N.J.A.; Hoorn, van, Hedde

    1999-01-01

    This paper gives a detailed empirical analysis of the relationships between different indicators of costs of commuting trips by car: difference as the crow flies, shortest travel time according to route planner, corresponding travel distance, and reported travel time. Reported travel times are usually rounded in multiples of five minutes. This calls for special statistical techniques. Ignoring the phenomenon of rounding leads to biased estimation results for shorter distances. Rather surprisi...

  14. Demographics, health and travel characteristics of international travellers at a pre-travel clinic in Marseille, France

    OpenAIRE

    Aubry, Camille; Gaudart, Jean; Gaillard, Catherine; Delmont, Jean; Parola, Philippe; Brouqui, Philippe; Gautret, Philippe

    2012-01-01

    International audience With the aim to identify at-risk individuals among a cohort of international travellers , 3442 individuals who sought advice at Marseille travel health centre in 2009 were prospectively included. Demographics, travel characteristics, chronic medical conditions, vaccinations and antimalarial chemoprophylaxis were documented. Chronic medical conditions were reported by 11% of individuals, including hypertension (39%), asthma (20%), thyroid disease (15%) and depression ...

  15. Application of the Expanded Theory of Planned Behavior in Intercity Travel Behavior

    Directory of Open Access Journals (Sweden)

    Jing Peng

    2014-01-01

    Full Text Available Congestion in intercity corridors of metropolitan area has been increasing steadily. To alleviate congestion, many major investment projects, such as the high speed railway projects, were proposed by agency. To evaluate the adequacy and efficiency of these projects, the intercity travel behavior should be analyzed in metropolitan area. The paper constructed a Multiple Indicators and Multiple Causes (MIMIC model according to an expanded theory of planned behavior (TPB to study the travel behavior of choosing from the choice set of the traditional train, the high speed railway and the coach by demographic and psychological factors. Through empirical data collection and analysis, we found that demographic factors of travelers indeed positively engender the latent variables in MIMIC, and descriptive norm and habit had direct or indirect significant effect on travel behavior and intention. On the basis of the effect of psychological constructors of the expanded TPB on the intercity travel behavior and differentiation of traveler's demographic characteristics, the agency can make reasonable policies and proper information for the intercity transportation. The results will support the basic theory of optimizing the transportation system in metropolitan area. Implications for researchers and suggestions for future research are also addressed in this study.

  16. Travelers' Health: Animal-Associated Hazards

    Science.gov (United States)

    ... Learn About Destination See a Doctor Pre-Travel Appointment Your Health Status How Diseases Spread Pack Smart ... or scratch from a bat anywhere in the world should be considered a risk, and the traveler ...

  17. Financial risks insurance in Russian travel industry

    Directory of Open Access Journals (Sweden)

    Elena A. Ivanova

    2011-03-01

    Full Text Available The article provides general characteristics of financial risks insurance in travel organizations activities, defines problem issues of legislation implementation, concerning tourist activities within travel cancellation insurance.

  18. Travel Recommendations for the Nursing Mother

    Science.gov (United States)

    ... Address What's this? Submit What's this? Submit Button Breastfeeding Information for Families Breastfeeding Hotline The HHS Office ... State and Local Programs Travel Recommendations for the Nursing Mother Recommend on Facebook Tweet Share Compartir Travel ...

  19. Travelers' Health: MERS in the Arabian Peninsula

    Science.gov (United States)

    ... Travelers’ Health website for more information on healthy travel. Health care workers People who are traveling to provide health care services in the Arabian Peninsula should review CDC’s recommendations for infection control of confirmed or ...

  20. Air travel, life-style, energy use and environmental impact

    Energy Technology Data Exchange (ETDEWEB)

    Krueger Nielsen, S.

    2001-09-01

    shown in this report, the current level of passenger air travel per capita in Europe may be considered within environmentally sustainable limits by the middle of this century provided that the current average greenhouse gas intensity of air travel is halved by then. Conversely, for exsample, an average American citizen today travels almost three times as much by air as an average European, thereby already exceeding the sustainabillity target for the World's citizens on average by the middle of this century that is proposed in this report. (EHS)