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Sample records for heavy-tailed inter-event time

  1. Analysis of Heavy-Tailed Time Series

    DEFF Research Database (Denmark)

    Xie, Xiaolei

    This thesis is about analysis of heavy-tailed time series. We discuss tail properties of real-world equity return series and investigate the possibility that a single tail index is shared by all return series of actively traded equities in a market. Conditions for this hypothesis to be true...... are identified. We study the eigenvalues and eigenvectors of sample covariance and sample auto-covariance matrices of multivariate heavy-tailed time series, and particularly for time series with very high dimensions. Asymptotic approximations of the eigenvalues and eigenvectors of such matrices are found...... and expressed in terms of the parameters of the dependence structure, among others. Furthermore, we study an importance sampling method for estimating rare-event probabilities of multivariate heavy-tailed time series generated by matrix recursion. We show that the proposed algorithm is efficient in the sense...

  2. Random matrix theory for heavy-tailed time series

    DEFF Research Database (Denmark)

    Heiny, Johannes

    2017-01-01

    This paper is a review of recent results for large random matrices with heavy-tailed entries. First, we outline the development of and some classical results in random matrix theory. We focus on large sample covariance matrices, their limiting spectral distributions, the asymptotic behavior...

  3. Direct Observation of Heavy-Tailed Storage Times of Bed Load Tracer Particles Causing Anomalous Superdiffusion

    Science.gov (United States)

    Bradley, D. Nathan

    2017-12-01

    A consensus has formed that the step length distribution of fluvial bed load is thin tailed and that the observed anomalous superdiffusion of bed load tracer particles must arise from heavy-tailed resting times. However, heavy-tailed resting times have never been directly observed in the field over multiple floods. Using 9 years of data from a large bed load tracer experiment, I show that the spatial variance of the tracer plume scales faster than linearly with integrated excess stream power, indicating anomalous superdiffusion. The superdiffusion is caused by a heavy-tailed distribution of observed storage times that is fit with a truncated Pareto distribution with a tail parameter that is predicted by anomalous diffusion theory. The heavy-tailed distribution of storage times causes the tracer virtual velocity to slow over time, indicated by a sublinear increase in the mean displacement that is predicted by the storage time distribution tail parameter.

  4. The M/G/1 queue with heavy-tailed service time distribution

    NARCIS (Netherlands)

    Boxma, O.J.; Cohen, J.W.

    1998-01-01

    In modern teletraffic applications of queueing theory, service time distributions B(t) with a heavy tail occur, i.e., 1-B(t)~Ct-v for t¿8 with v>1. For such service time distributions, not much explicit information is available concerning the tail probabilities of the corresponding waiting time

  5. From heavy-tailed to exponential distribution of interevent time in cellphone top-up behavior

    Science.gov (United States)

    Wang, Peng; Ma, Qiang

    2017-05-01

    Cellphone top-up is a kind of activities, to a great extent, driven by individual consumption rather than personal interest and this behavior should be stable in common sense. However, our researches find there are heavy-tails both in interevent time distribution and purchase frequency distribution at the global level. Moreover, we find both memories of interevent time and unit price series are negative, which is different from previous bursty activities. We divide individuals into five groups according to the purchase frequency and the average unit price respectively. Then, the group analysis shows some significant heterogeneity in this behavior. On one hand, we obtain only the individuals with high purchase frequency have the heavy-tailed nature in interevent time distribution. On the contrary, the negative memory is only caused by low purchase-frequency individuals without burstiness. On the other hand, the individuals with different preferential price also have different power-law exponents at the group level and there is no data collapse after rescaling between these distributions. Our findings produce the evidence for the significant heterogeneity of human activity in many aspects.

  6. Convolutions of Heavy Tailed Random Variables and Applications to Portfolio Diversification and MA(1) Time Series

    NARCIS (Netherlands)

    J.L. Geluk (Jaap); L. Peng (Liang); C.G. de Vries (Casper)

    1999-01-01

    textabstractThe paper characterizes first and second order tail behavior of convolutions of i.i.d. heavy tailed random variables with support on the real line. The result is applied to the problem of risk diversification in portfolio analysis and to the estimation of the parameter in a MA(1) model.

  7. Statistical Property and Model for the Inter-Event Time of Terrorism Attacks

    Science.gov (United States)

    Zhu, Jun-Fang; Han, Xiao-Pu; Wang, Bing-Hong

    2010-06-01

    The inter-event time of terrorism attack events is investigated by empirical data and model analysis. Empirical evidence shows that it follows a scale-free property. In order to understand the dynamic mechanism of such a statistical feature, an opinion dynamic model with a memory effect is proposed on a two-dimensional lattice network. The model mainly highlights the role of individual social conformity and self-affirmation psychology. An attack event occurs when the order parameter indicating the strength of public opposition opinion is smaller than a critical value. Ultimately, the model can reproduce the same statistical property as the empirical data and gives a good understanding for the possible dynamic mechanism of terrorism attacks.

  8. Sojourn time tails in the single server queue with heavy-tailed service times

    NARCIS (Netherlands)

    Boxma, O.J.; Denisov, D.E.

    2009-01-01

    We consider the GI/GI/1 queue with regularly varying service requirement distribution of index -a. It is well known that, in the M/G/1 FCFS queue, the sojourn time distribution is also regularly varying, of index 1 - a, whereas in the case of LCFS or Processor Sharing, the sojourn time distribution

  9. Sojourn time tails in the single server queue with heavy-tailed service times

    NARCIS (Netherlands)

    Boxma, O.J.; Denisov, D.E.

    2011-01-01

    We consider the GI/GI/1 queue with regularly varying service requirement distribution of index -a. It is well known that, in the M/G/1 FCFS queue, the sojourn time distribution is also regularly varying, of index 1-a, whereas in the case of LCFS or Processor Sharing, the sojourn time distribution is

  10. Inter-Event Time Definition Setting Procedure for Urban Drainage Systems

    Directory of Open Access Journals (Sweden)

    Jingul Joo

    2013-12-01

    Full Text Available Traditional inter-event time definition (IETD estimate methodologies generally take into account only rainfall characteristics and not drainage basin characteristics. Therefore, they may not succeed in providing an appropriate value of IETD for any sort of application to the design of urban drainage system devices. To overcome this limitation, this study presents a method of IETD determination that considers basin characteristics. The suggested definition of IETD is the time period from the end of a rainfall event to the end of a direct runoff. The suggested method can identify the independent events that are suitable for the statistical analysis of the recorded rainfall. Using the suggested IETD, the IETD of the Joong-Rang drainage system was determined and the area-IETD relation curve was drawn. The resulting regression curve can be used to determinate the IETD of ungauged urban drainage systems, with areas ranging between 40 and 4400 ha. Using the regression curve, the IETDs and time distribution of the design rainfall for four drainage systems in Korea were determined and rainfall-runoff simulations were performed with the Storm Water Management Model (SWMM. The results were compared with those from Huff's method which assumed a six-hour IETD. The peak flow rates obtained by the suggested method were 11%~15% greater than those obtained by Huff’s method. The suggested IETD determination method can identify independent events that are suitable for the statistical analysis of the recorded rainfall aimed at the design of urban drainage system devices.

  11. Second order corrections for the limits of normalized ruin times in the presence of heavy tails

    DEFF Research Database (Denmark)

    Asmussen, Søren; Kortschak, Dominik

    In this paper we consider a compound Poisson risk model with regularly varying claim sizes. For this model in [4] an asymptotic formula for the finite time ruin probability is provided when the time is scaled by the mean excess function. In this paper we derive the rate of convergence for this fi...

  12. Matrix diffusion: heavy-tailed residence time distributions and their influence on radionuclide retention

    International Nuclear Information System (INIS)

    Haggerty, R.

    2002-01-01

    Matrix diffusion in rocks is frequently assumed to be both Fickian and effectively homogeneous over space- and time-scales relevant to radionuclide retention. This paper discusses some cases of rocks where one or both of these assumptions may be invalid and what the consequences may be for modeling and performance assessment: a single pore diffusivity and matrix block size which is not representative of the diffusion process at all time- or space-scales, a scale-dependent diffusion rate coefficient which decreases with time- and space-scales, a retention capacity of host rocks that may be smaller than apparent in laboratory and field tests because all of the pore space is not accessible via diffusion over the performance assessment-scale transport time. (J.S.)

  13. Asymptotic theory for the sample covariance matrix of a heavy-tailed multivariate time series

    DEFF Research Database (Denmark)

    Davis, Richard A.; Mikosch, Thomas Valentin; Pfaffel, Olivier

    2016-01-01

    In this paper we give an asymptotic theory for the eigenvalues of the sample covariance matrix of a multivariate time series. The time series constitutes a linear process across time and between components. The input noise of the linear process has regularly varying tails with index α∈(0,4) in...... particular, the time series has infinite fourth moment. We derive the limiting behavior for the largest eigenvalues of the sample covariance matrix and show point process convergence of the normalized eigenvalues. The limiting process has an explicit form involving points of a Poisson process and eigenvalues...... of a non-negative definite matrix. Based on this convergence we derive limit theory for a host of other continuous functionals of the eigenvalues, including the joint convergence of the largest eigenvalues, the joint convergence of the largest eigenvalue and the trace of the sample covariance matrix...

  14. The ruin probability of a discrete time risk model under constant interest rate with heavy tails

    NARCIS (Netherlands)

    Tang, Q.

    2004-01-01

    This paper investigates the ultimate ruin probability of a discrete time risk model with a positive constant interest rate. Under the assumption that the gross loss of the company within one year is subexponentially distributed, a simple asymptotic relation for the ruin probability is derived and

  15. Prediction problem for target events based on the inter-event waiting time

    Science.gov (United States)

    Shapoval, A.

    2010-11-01

    In this paper we address the problem of forecasting the target events of a time series given the distribution ξ of time gaps between target events. Strong earthquakes and stock market crashes are the two types of such events that we are focusing on. In the series of earthquakes, as McCann et al. show [W.R. Mc Cann, S.P. Nishenko, L.R. Sykes, J. Krause, Seismic gaps and plate tectonics: seismic potential for major boundaries, Pure and Applied Geophysics 117 (1979) 1082-1147], there are well-defined gaps (called seismic gaps) between strong earthquakes. On the other hand, usually there are no regular gaps in the series of stock market crashes [M. Raberto, E. Scalas, F. Mainardi, Waiting-times and returns in high-frequency financial data: an empirical study, Physica A 314 (2002) 749-755]. For the case of seismic gaps, we analytically derive an upper bound of prediction efficiency given the coefficient of variation of the distribution ξ. For the case of stock market crashes, we develop an algorithm that predicts the next crash within a certain time interval after the previous one. We show that this algorithm outperforms random prediction. The efficiency of our algorithm sets up a lower bound of efficiency for effective prediction of stock market crashes.

  16. Spectral narrowing and spin echo for localized carriers with heavy-tailed L evy distribution of hopping times

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Z. [Univ. of Utah, Salt Lake City, UT (United States); Mkhitaryan, Vagharsh [Ames Lab. and Iowa State Univ., Ames, IA (United States); Raikh, M. E. [Univ. of Utah, Salt Lake City, UT (United States)

    2016-02-02

    We study analytically the free induction decay and the spin echo decay originating from the localized carriers moving between the sites which host random magnetic fields. Due to disorder in the site positions and energies, the on-site residence times, , are widely spread according to the L evy distribution. The power-law tail ∝ τ-1-∝ in the distribution of does not affect the conventional spectral narrowing for α > 2, but leads to a dramatic acceleration of the free induction decay in the domain 2 > α > 1. The next abrupt acceleration of the decay takes place as becomes smaller than 1. In the latter domain the decay does not follow a simple-exponent law. To capture the behavior of the average spin in this domain, we solve the evolution equation for the average spin using the approach different from the conventional approach based on the Laplace transform. Unlike the free induction decay, the tail in the distribution of the residence times leads to the slow decay of the spin echo. The echo is dominated by realizations of the carrier motion for which the number of sites, visited by the carrier, is minimal.

  17. Focal mechanisms and inter-event times of low-frequency earthquakes reveal quasi-continuous deformation and triggered slow slip on the deep Alpine Fault

    Science.gov (United States)

    Baratin, Laura-May; Chamberlain, Calum J.; Townend, John; Savage, Martha K.

    2018-02-01

    Characterising the seismicity associated with slow deformation in the vicinity of the Alpine Fault may provide constraints on the stresses acting on a major transpressive margin prior to an anticipated great (≥M8) earthquake. Here, we use recently detected tremor and low-frequency earthquakes (LFEs) to examine how slow tectonic deformation is loading the Alpine Fault late in its typical ∼300-yr seismic cycle. We analyse a continuous seismic dataset recorded between 2009 and 2016 using a network of 10-13 short-period seismometers, the Southern Alps Microearthquake Borehole Array. Fourteen primary LFE templates are used in an iterative matched-filter and stacking routine, allowing the detection of similar signals corresponding to LFE families sharing common locations. This yields an 8-yr catalogue containing 10,000 LFEs that are combined for each of the 14 LFE families using phase-weighted stacking to produce signals with the highest possible signal-to-noise ratios. We show that LFEs occur almost continuously during the 8-yr study period and highlight two types of LFE distributions: (1) discrete behaviour with an inter-event time exceeding 2 min; (2) burst-like behaviour with an inter-event time below 2 min. We interpret the discrete events as small-scale frequent deformation on the deep extent of the Alpine Fault and LFE bursts (corresponding in most cases to known episodes of tremor or large regional earthquakes) as brief periods of increased slip activity indicative of slow slip. We compute improved non-linear earthquake locations using a 3-D velocity model. LFEs occur below the seismogenic zone at depths of 17-42 km, on or near the hypothesised deep extent of the Alpine Fault. The first estimates of LFE focal mechanisms associated with continental faulting, in conjunction with recurrence intervals, are consistent with quasi-continuous shear faulting on the deep extent of the Alpine Fault.

  18. Heavy Tail Behavior of Rainfall Extremes across Germany

    Science.gov (United States)

    Castellarin, A.; Kreibich, H.; Vorogushyn, S.; Merz, B.

    2017-12-01

    Distributions are termed heavy-tailed if extreme values are more likely than would be predicted by probability distributions that have exponential asymptotic behavior. Heavy-tail behavior often leads to surprise, because historical observations can be a poor guide for the future. Heavy-tail behavior seems to be widespread for hydro-meteorological extremes, such as extreme rainfall and flood events. To date there have been only vague hints to explain under which conditions these extremes show heavy-tail behavior. We use an observational data set consisting of 11 climate variables at 1440 stations across Germany. This homogenized, gap-free data set covers 110 years (1901-2010) at daily resolution. We estimate the upper tail behavior, including its uncertainty interval, of daily precipitation extremes for the 1,440 stations at the annual and seasonal time scales. Different tail indicators are tested, including the shape parameter of the Generalized Extreme Value distribution, the upper tail ratio and the obesity index. In a further step, we explore to which extent the tail behavior can be explained by geographical and climate factors. A large number of characteristics is derived, such as station elevation, degree of continentality, aridity, measures for quantifying the variability of humidity and wind velocity, or event-triggering large-scale atmospheric situation. The link between the upper tail behavior and these characteristics is investigated via data mining methods capable of detecting non-linear relationships in large data sets. This exceptionally rich observational data set, in terms of number of stations, length of time series and number of explaining variables, allows insights into the upper tail behavior which is rarely possible given the typical observational data sets available.

  19. Understanding the heavy-tailed dynamics in human behavior

    Science.gov (United States)

    Ross, Gordon J.; Jones, Tim

    2015-06-01

    The recent availability of electronic data sets containing large volumes of communication data has made it possible to study human behavior on a larger scale than ever before. From this, it has been discovered that across a diverse range of data sets, the interevent times between consecutive communication events obey heavy-tailed power law dynamics. Explaining this has proved controversial, and two distinct hypotheses have emerged. The first holds that these power laws are fundamental, and arise from the mechanisms such as priority queuing that humans use to schedule tasks. The second holds that they are statistical artifacts which only occur in aggregated data when features such as circadian rhythms and burstiness are ignored. We use a large social media data set to test these hypotheses, and find that although models that incorporate circadian rhythms and burstiness do explain part of the observed heavy tails, there is residual unexplained heavy-tail behavior which suggests a more fundamental cause. Based on this, we develop a quantitative model of human behavior which improves on existing approaches and gives insight into the mechanisms underlying human interactions.

  20. Forecast Combination under Heavy-Tailed Errors

    Directory of Open Access Journals (Sweden)

    Gang Cheng

    2015-11-01

    Full Text Available Forecast combination has been proven to be a very important technique to obtain accurate predictions for various applications in economics, finance, marketing and many other areas. In many applications, forecast errors exhibit heavy-tailed behaviors for various reasons. Unfortunately, to our knowledge, little has been done to obtain reliable forecast combinations for such situations. The familiar forecast combination methods, such as simple average, least squares regression or those based on the variance-covariance of the forecasts, may perform very poorly due to the fact that outliers tend to occur, and they make these methods have unstable weights, leading to un-robust forecasts. To address this problem, in this paper, we propose two nonparametric forecast combination methods. One is specially proposed for the situations in which the forecast errors are strongly believed to have heavy tails that can be modeled by a scaled Student’s t-distribution; the other is designed for relatively more general situations when there is a lack of strong or consistent evidence on the tail behaviors of the forecast errors due to a shortage of data and/or an evolving data-generating process. Adaptive risk bounds of both methods are developed. They show that the resulting combined forecasts yield near optimal mean forecast errors relative to the candidate forecasts. Simulations and a real example demonstrate their superior performance in that they indeed tend to have significantly smaller prediction errors than the previous combination methods in the presence of forecast outliers.

  1. Optimal heavy tail estimation – Part 1: Order selection

    Directory of Open Access Journals (Sweden)

    M. Mudelsee

    2017-12-01

    Full Text Available The tail probability, P, of the distribution of a variable is important for risk analysis of extremes. Many variables in complex geophysical systems show heavy tails, where P decreases with the value, x, of a variable as a power law with a characteristic exponent, α. Accurate estimation of α on the basis of data is currently hindered by the problem of the selection of the order, that is, the number of largest x values to utilize for the estimation. This paper presents a new, widely applicable, data-adaptive order selector, which is based on computer simulations and brute force search. It is the first in a set of papers on optimal heavy tail estimation. The new selector outperforms competitors in a Monte Carlo experiment, where simulated data are generated from stable distributions and AR(1 serial dependence. We calculate error bars for the estimated α by means of simulations. We illustrate the method on an artificial time series. We apply it to an observed, hydrological time series from the River Elbe and find an estimated characteristic exponent of 1.48 ± 0.13. This result indicates finite mean but infinite variance of the statistical distribution of river runoff.

  2. Entropy-based heavy tailed distribution transformation and visual analytics for monitoring massive network traffic

    Science.gov (United States)

    Han, Keesook J.; Hodge, Matthew; Ross, Virginia W.

    2011-06-01

    For monitoring network traffic, there is an enormous cost in collecting, storing, and analyzing network traffic datasets. Data mining based network traffic analysis has a growing interest in the cyber security community, but is computationally expensive for finding correlations between attributes in massive network traffic datasets. To lower the cost and reduce computational complexity, it is desirable to perform feasible statistical processing on effective reduced datasets instead of on the original full datasets. Because of the dynamic behavior of network traffic, traffic traces exhibit mixtures of heavy tailed statistical distributions or overdispersion. Heavy tailed network traffic characterization and visualization are important and essential tasks to measure network performance for the Quality of Services. However, heavy tailed distributions are limited in their ability to characterize real-time network traffic due to the difficulty of parameter estimation. The Entropy-Based Heavy Tailed Distribution Transformation (EHTDT) was developed to convert the heavy tailed distribution into a transformed distribution to find the linear approximation. The EHTDT linearization has the advantage of being amenable to characterize and aggregate overdispersion of network traffic in realtime. Results of applying the EHTDT for innovative visual analytics to real network traffic data are presented.

  3. Approximation for the Finite-Time Ruin Probability of a General Risk Model with Constant Interest Rate and Extended Negatively Dependent Heavy-Tailed Claims

    Directory of Open Access Journals (Sweden)

    Yang Yang

    2011-01-01

    Full Text Available We propose a general continuous-time risk model with a constant interest rate. In this model, claims arrive according to an arbitrary counting process, while their sizes have dominantly varying tails and fulfill an extended negative dependence structure. We obtain an asymptotic formula for the finite-time ruin probability, which extends a corresponding result of Wang (2008.

  4. Comparing downside risk measures for heavy tailed distributions

    NARCIS (Netherlands)

    Daníelsson, J.; Jorgensen, B.N.; Sarma, M.; Vries, de C.G.

    2006-01-01

    Using regular variation to define heavy tailed distributions, we show that prominent downside risk measures produce similar and consistent ranking of heavy tailed risk. Thus, regardless of the particular risk measure being used, assets will be ranked in a similar and consistent manner for heavy

  5. Heavy-traffic analysis for the GI/G/1 queue with heavy-tailed distributions

    NARCIS (Netherlands)

    O.J. Boxma (Onno); J.W. Cohen

    1997-01-01

    textabstractWe consider a $GI/G/1$ queue in which the service time distribution and/or the interarrival time distribution has a heavy tail, i.e., a tail behaviour like $t^{-nu$ with $1

  6. Heavy-tailed distributions and robustness in economics and finance

    CERN Document Server

    Ibragimov, Marat; Walden, Johan

    2015-01-01

    This book focuses on general frameworks for modeling heavy-tailed distributions in economics, finance, econometrics, statistics, risk management and insurance. A central theme is that of (non-)robustness, i.e., the fact that the presence of heavy tails can either reinforce or reverse the implications of a number of models in these fields, depending on the degree of heavy-tailedness. These results motivate the development and applications of robust inference approaches under heavy tails, heterogeneity and dependence in observations. Several recently developed robust inference approaches are discussed and illustrated, together with applications.

  7. Goodness-of-fit tests for a heavy tailed distribution

    NARCIS (Netherlands)

    A.J. Koning (Alex); L. Peng (Liang)

    2005-01-01

    textabstractFor testing whether a distribution function is heavy tailed, we study the Kolmogorov test, Berk-Jones test, score test and their integrated versions. A comparison is conducted via Bahadur efficiency and simulations. The score test and the integrated score test show the best

  8. Power-law cross-correlations estimation under heavy tails

    Czech Academy of Sciences Publication Activity Database

    Krištoufek, Ladislav

    2016-01-01

    Roč. 40, č. 1 (2016), s. 163-172 ISSN 1007-5704 R&D Projects: GA ČR(CZ) GP14-11402P Institutional support: RVO:67985556 Keywords : Power-law cross-correlations * Heavy tails * Monte Carlo study Subject RIV: AH - Economics Impact factor: 2.784, year: 2016 http://library.utia.cas.cz/separaty/2016/E/kristoufek-0472030.pdf

  9. On Hurst exponent estimation under heavy-tailed distributions

    Czech Academy of Sciences Publication Activity Database

    Baruník, Jozef; Krištoufek, Ladislav

    2010-01-01

    Roč. 389, č. 18 (2010), s. 3844-3855 ISSN 0378-4371 R&D Projects: GA ČR GA402/09/0965 Grant - others:GA UK(CZ) 118310; GA UK(CZ) 46108 Institutional research plan: CEZ:AV0Z10750506 Keywords : high frequency data analysis * heavy tails * Hurst exponent Subject RIV: AH - Economics Impact factor: 1.521, year: 2010 http://library.utia.cas.cz/separaty/2010/E/barunik-0343525.pdf

  10. On the Favorable Estimation for Fitting Heavy Tailed Data

    Czech Academy of Sciences Publication Activity Database

    Stehlík, M.; Potocký, R.; Waldl, H.; Fabián, Zdeněk

    2010-01-01

    Roč. 25, č. 3 (2010), s. 485-503 ISSN 0943-4062 Grant - others:ASO(SK) SK-0607-BA-018; VEGA(SK) 1/0077/09; 50p14(CZ-AT) AKTION; AKTION(CZ-AT) 54p13 Institutional research plan: CEZ:AV0Z10300504 Keywords : heavy-tailed distribution * exact likelihood ratio test * T-score moment estimator * insurance * Basel II Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.500, year: 2010

  11. Top Incomes, Heavy Tails, and Rank-Size Regressions

    Directory of Open Access Journals (Sweden)

    Christian Schluter

    2018-03-01

    Full Text Available In economics, rank-size regressions provide popular estimators of tail exponents of heavy-tailed distributions. We discuss the properties of this approach when the tail of the distribution is regularly varying rather than strictly Pareto. The estimator then over-estimates the true value in the leading parametric income models (so the upper income tail is less heavy than estimated, which leads to test size distortions and undermines inference. For practical work, we propose a sensitivity analysis based on regression diagnostics in order to assess the likely impact of the distortion. The methods are illustrated using data on top incomes in the UK.

  12. Similarity of Symbol Frequency Distributions with Heavy Tails

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    Martin Gerlach

    2016-04-01

    Full Text Available Quantifying the similarity between symbolic sequences is a traditional problem in information theory which requires comparing the frequencies of symbols in different sequences. In numerous modern applications, ranging from DNA over music to texts, the distribution of symbol frequencies is characterized by heavy-tailed distributions (e.g., Zipf’s law. The large number of low-frequency symbols in these distributions poses major difficulties to the estimation of the similarity between sequences; e.g., they hinder an accurate finite-size estimation of entropies. Here, we show analytically how the systematic (bias and statistical (fluctuations errors in these estimations depend on the sample size N and on the exponent γ of the heavy-tailed distribution. Our results are valid for the Shannon entropy (α=1, its corresponding similarity measures (e.g., the Jensen-Shanon divergence, and also for measures based on the generalized entropy of order α. For small α’s, including α=1, the errors decay slower than the 1/N decay observed in short-tailed distributions. For α larger than a critical value α^{*}=1+1/γ≤2, the 1/N decay is recovered. We show the practical significance of our results by quantifying the evolution of the English language over the last two centuries using a complete α spectrum of measures. We find that frequent words change more slowly than less frequent words and that α=2 provides the most robust measure to quantify language change.

  13. Generalized randomly amplified linear system driven by Gaussian noises: Extreme heavy tail and algebraic correlation decay in plasma turbulence

    International Nuclear Information System (INIS)

    Steinbrecher, Gyoergy; Weyssow, B.

    2004-01-01

    The extreme heavy tail and the power-law decay of the turbulent flux correlation observed in hot magnetically confined plasmas are modeled by a system of coupled Langevin equations describing a continuous time linear randomly amplified stochastic process where the amplification factor is driven by a superposition of colored noises which, in a suitable limit, generate a fractional Brownian motion. An exact analytical formula for the power-law tail exponent β is derived. The extremely small value of the heavy tail exponent and the power-law distribution of laminar times also found experimentally are obtained, in a robust manner, for a wide range of input values, as a consequence of the (asymptotic) self-similarity property of the noise spectrum. As a by-product, a new representation of the persistent fractional Brownian motion is obtained

  14. Bursts and heavy tails in temporal and sequential dynamics of foraging decisions.

    Directory of Open Access Journals (Sweden)

    Kanghoon Jung

    2014-08-01

    Full Text Available A fundamental understanding of behavior requires predicting when and what an individual will choose. However, the actual temporal and sequential dynamics of successive choices made among multiple alternatives remain unclear. In the current study, we tested the hypothesis that there is a general bursting property in both the timing and sequential patterns of foraging decisions. We conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. Regarding when choices were made, we found bursts of rapidly occurring actions, separated by time-varying inactive periods, partially based on a circadian rhythm. Regarding what was chosen, we found sequential dynamics in affective choices characterized by two key features: (a a highly biased choice distribution; and (b preferential attachment, in which the animals were more likely to choose what they had previously chosen. To capture the temporal dynamics, we propose a dual-state model consisting of active and inactive states. We also introduce a satiation-attainment process for bursty activity, and a non-homogeneous Poisson process for longer inactivity between bursts. For the sequential dynamics, we propose a dual-control model consisting of goal-directed and habit systems, based on outcome valuation and choice history, respectively. This study provides insights into how the bursty nature of behavior emerges from the interaction of different underlying systems, leading to heavy tails in the distribution of behavior over time and choices.

  15. Bursts and Heavy Tails in Temporal and Sequential Dynamics of Foraging Decisions

    Science.gov (United States)

    Jung, Kanghoon; Jang, Hyeran; Kralik, Jerald D.; Jeong, Jaeseung

    2014-01-01

    A fundamental understanding of behavior requires predicting when and what an individual will choose. However, the actual temporal and sequential dynamics of successive choices made among multiple alternatives remain unclear. In the current study, we tested the hypothesis that there is a general bursting property in both the timing and sequential patterns of foraging decisions. We conducted a foraging experiment in which rats chose among four different foods over a continuous two-week time period. Regarding when choices were made, we found bursts of rapidly occurring actions, separated by time-varying inactive periods, partially based on a circadian rhythm. Regarding what was chosen, we found sequential dynamics in affective choices characterized by two key features: (a) a highly biased choice distribution; and (b) preferential attachment, in which the animals were more likely to choose what they had previously chosen. To capture the temporal dynamics, we propose a dual-state model consisting of active and inactive states. We also introduce a satiation-attainment process for bursty activity, and a non-homogeneous Poisson process for longer inactivity between bursts. For the sequential dynamics, we propose a dual-control model consisting of goal-directed and habit systems, based on outcome valuation and choice history, respectively. This study provides insights into how the bursty nature of behavior emerges from the interaction of different underlying systems, leading to heavy tails in the distribution of behavior over time and choices. PMID:25122498

  16. Empirical Estimates in Optimization Problems: Survey with Special Regard to Heavy Tails and Dependent Data

    Czech Academy of Sciences Publication Activity Database

    Kaňková, Vlasta

    2012-01-01

    Roč. 19, č. 30 (2012), s. 92-111 ISSN 1212-074X R&D Projects: GA ČR GAP402/10/0956; GA ČR GAP402/11/0150; GA ČR GAP402/10/1610 Institutional support: RVO:67985556 Keywords : Stochastic optimization * empirical estimates * thin and heavy tails * independent and weak dependent random samples Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2013/E/kankova-empirical estimates in optimization problems survey with special regard to heavy tails and dependent data.pdf

  17. Chapter two: Phenomenology of tsunamis II: scaling, event statistics, and inter-event triggering

    Science.gov (United States)

    Geist, Eric L.

    2012-01-01

    Observations related to tsunami catalogs are reviewed and described in a phenomenological framework. An examination of scaling relationships between earthquake size (as expressed by scalar seismic moment and mean slip) and tsunami size (as expressed by mean and maximum local run-up and maximum far-field amplitude) indicates that scaling is significant at the 95% confidence level, although there is uncertainty in how well earthquake size can predict tsunami size (R2 ~ 0.4-0.6). In examining tsunami event statistics, current methods used to estimate the size distribution of earthquakes and landslides and the inter-event time distribution of earthquakes are first reviewed. These methods are adapted to estimate the size and inter-event distribution of tsunamis at a particular recording station. Using a modified Pareto size distribution, the best-fit power-law exponents of tsunamis recorded at nine Pacific tide-gauge stations exhibit marked variation, in contrast to the approximately constant power-law exponent for inter-plate thrust earthquakes. With regard to the inter-event time distribution, significant temporal clustering of tsunami sources is demonstrated. For tsunami sources occurring in close proximity to other sources in both space and time, a physical triggering mechanism, such as static stress transfer, is a likely cause for the anomalous clustering. Mechanisms of earthquake-to-earthquake and earthquake-to-landslide triggering are reviewed. Finally, a modification of statistical branching models developed for earthquake triggering is introduced to describe triggering among tsunami sources.

  18. Understanding the distinctively skewed and heavy tailed character of atmospheric and oceanic probability distributions

    Energy Technology Data Exchange (ETDEWEB)

    Sardeshmukh, Prashant D., E-mail: Prashant.D.Sardeshmukh@noaa.gov [CIRES, University of Colorado, Boulder, Colorado 80309 (United States); NOAA/Earth System Research Laboratory, Boulder, Colorado 80305 (United States); Penland, Cécile [NOAA/Earth System Research Laboratory, Boulder, Colorado 80305 (United States)

    2015-03-15

    The probability distributions of large-scale atmospheric and oceanic variables are generally skewed and heavy-tailed. We argue that their distinctive departures from Gaussianity arise fundamentally from the fact that in a quadratically nonlinear system with a quadratic invariant, the coupling coefficients between system components are not constant but depend linearly on the system state in a distinctive way. In particular, the skewness arises from a tendency of the system trajectory to linger near states of weak coupling. We show that the salient features of the observed non-Gaussianity can be captured in the simplest such nonlinear 2-component system. If the system is stochastically forced and linearly damped, with one component damped much more strongly than the other, then the strongly damped fast component becomes effectively decoupled from the weakly damped slow component, and its impact on the slow component can be approximated as a stochastic noise forcing plus an augmented nonlinear damping. In the limit of large time-scale separation, the nonlinear augmentation of the damping becomes small, and the noise forcing can be approximated as an additive noise plus a correlated additive and multiplicative noise (CAM noise) forcing. Much of the diversity of observed large-scale atmospheric and oceanic probability distributions can be interpreted in this minimal framework.

  19. Tail Asymptotics for the Sum of two Heavy-tailed Dependent Risks

    DEFF Research Database (Denmark)

    Albrecher, H.; Asmussen, Søren

    Let X1,X2 denote positive exchangable heavy-tailed random variables with continuous marginal distribution function F. The asymptotic behavior of the tail of X1 + X2 is studied in a general copula framework and some bounds and extremal properties are provided. For more specific assumptions on F...

  20. Degree-degree correlations in directed networks with heavy-tailed degrees

    NARCIS (Netherlands)

    van der Hoorn, W.L.F.; Litvak, Nelli

    2013-01-01

    In network theory, Pearson's correlation coefficients are most commonly used to measure the degree assortativity of a network. We investigate the behavior of these coefficients in the setting of directed networks with heavy-tailed degree sequences. We prove that for graphs where the in- and

  1. Degree-degree dependencies in directed networks with heavy-tailed degrees

    NARCIS (Netherlands)

    van der Hoorn, W.L.F.; Litvak, Nelly

    2015-01-01

    In network theory, Pearson’s correlation coefficients are most commonly used to measure the degree assortativity of a network. We investigate the behavior of these coefficients in the setting of directed networks with heavy-tailed degree sequences. We prove that for graphs where the in- and

  2. Calculation of ruin probabilities for a dense class of heavy tailed distributions

    DEFF Research Database (Denmark)

    Bladt, Mogens; Nielsen, Bo Friis; Samorodnitsky, Gennady

    2015-01-01

    In this paper, we propose a class of infinite-dimensional phase-type distributions with finitely many parameters as models for heavy tailed distributions. The class of finite-dimensional phase-type distributions is dense in the class of distributions on the positive reals and may hence approximate...... any such distribution. We prove that formulas from renewal theory, and with a particular attention to ruin probabilities, which are true for common phase-type distributions also hold true for the infinite-dimensional case. We provide algorithms for calculating functionals of interest...... such as the renewal density and the ruin probability. It might be of interest to approximate a given heavy tailed distribution of some other type by a distribution from the class of infinite-dimensional phase-type distributions and to this end we provide a calibration procedure which works for the approximation...

  3. Heavy-tailed distribution of cyber-risks

    Science.gov (United States)

    Maillart, T.; Sornette, D.

    2010-06-01

    With the development of the Internet, new kinds of massive epidemics, distributed attacks, virtual conflicts and criminality have emerged. We present a study of some striking statistical properties of cyber-risks that quantify the distribution and time evolution of information risks on the Internet, to understand their mechanisms, and create opportunities to mitigate, control, predict and insure them at a global scale. First, we report an exceptionnaly stable power-law tail distribution of personal identity losses per event, Pr(ID loss ≥ V) ~ 1/Vb, with b = 0.7 ± 0.1. This result is robust against a surprising strong non-stationary growth of ID losses culminating in July 2006 followed by a more stationary phase. Moreover, this distribution is identical for different types and sizes of targeted organizations. Since b < 1, the cumulative number of all losses over all events up to time t increases faster-than-linear with time according to ≃ t1/b, suggesting that privacy, characterized by personal identities, is necessarily becoming more and more insecure. We also show the existence of a size effect, such that the largest possible ID losses per event grow faster-than-linearly as ~S1.3 with the organization size S. The small value b ≃ 0.7 of the power law distribution of ID losses is explained by the interplay between Zipf’s law and the size effect. We also infer that compromised entities exhibit basically the same probability to incur a small or large loss.

  4. An Estimator of Heavy Tail Index through the Generalized Jackknife Methodology

    Directory of Open Access Journals (Sweden)

    Weiqi Liu

    2014-01-01

    Full Text Available In practice, sometimes the data can be divided into several blocks but only a few of the largest observations within each block are available to estimate the heavy tail index. To address this problem, we propose a new class of estimators through the Generalized Jackknife methodology based on Qi’s estimator (2010. These estimators are proved to be asymptotically normal under suitable conditions. Compared to Hill’s estimator and Qi’s estimator, our new estimator has better asymptotic efficiency in terms of the minimum mean squared error, for a wide range of the second order shape parameters. For the finite samples, our new estimator still compares favorably to Hill’s estimator and Qi’s estimator, providing stable sample paths as a function of the number of dividing the sample into blocks, smaller estimation bias, and MSE.

  5. Coverage probability of bootstrap confidence intervals in heavy-tailed frequency models, with application to precipitation data

    Czech Academy of Sciences Publication Activity Database

    Kyselý, Jan

    2010-01-01

    Roč. 101, 3-4 (2010), s. 345-361 ISSN 0177-798X R&D Projects: GA AV ČR KJB300420801 Institutional research plan: CEZ:AV0Z30420517 Keywords : bootstrap * extreme value analysis * confidence intervals * heavy-tailed distributions * precipitation amounts Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.684, year: 2010

  6. Fate of phosphorus fractions in an adsorptive-filter subject to intra- and inter-event runoff phenomena.

    Science.gov (United States)

    Berretta, Christian; Sansalone, John

    2012-07-30

    In-situ filtration of phosphorus (P) and particulate matter (PM) transported in runoff is increasingly implemented for urban source areas. While monitoring of filter response is commonly based on an event mean of total phosphorus (TP), this study examines the fate of specific P fractions through intra- and inter-event phenomena. This continuous filter monitoring program includes 15 wet weather loadings and the dry weather periods between these events. Aqueous P adsorption and PM-bound P (suspended, settleable and sediment) filtration phenomena are examined for runoff events from a landscaped carpark with biogenic loads in Gainesville (GNV), FL. Filter response is compared to a similar aluminum oxide Al-Ox modified media filter subject to anthropogenic loads from an urban paved source area in Baton Rouge (BTR), LA. Results for the GNV filter indicate that while intra-event settleable, sediment and dissolved P fractions are controlled by the filter, the suspended P fraction remained relatively mobile compared to the other P fractions. P adsorption is primarily influenced by intra-event flow rates, contact times, runoff volume, pH and by the inter-event chemistry of runoff stored in the filter. P effluent partitioning is dominated by the suspended PM as a consequence of effective adsorption by the filter. Inter-event phenomena generate decreasing redox with commensurate increases in alkalinity, conductivity as well as dissolved P as a consequence of re-partitioning. Dissolved P fate suggests that filters should be designed and managed to remain aerobic between wet weather events. For effective separation of suspended P and PM fractions by passive filters with low driving head, sustainability of performance, including head loss {<3 kPa}, requires upstream volumetric attenuation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. A large deviations approach to limit theory for heavy-tailed time series

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; Wintenberger, Olivier

    2016-01-01

    and vanishing in some neighborhood of the origin. We study a variety of such functionals, including large deviations of random walks, their suprema, the ruin functional, and further derive weak limit theory for maxima, point processes, cluster functionals and the tail empirical process. One of the main results...

  8. Convolutions of Heavy Tailed Random Variables and Applications to Portfolio Diversification and MA(1) Time Series

    OpenAIRE

    Geluk, Jaap; Peng, Liang; de Vries, Casper G.

    1999-01-01

    Suppose X1,X2 are independent random variables satisfying a second-order regular variation condition on the tail-sum and a balance condition on the tails. In this paper we give a description of the asymptotic behaviour as t → ∞ for P(X1 + X2 > t). The result is applied to the problem of risk diversification in portfolio analysis and to the estimation of the parameter in a MA(1) model.

  9. Power laws for heavy-tailed distributions: modeling allele and haplotype diversity for the national marrow donor program.

    Directory of Open Access Journals (Sweden)

    Noa Slater

    2015-04-01

    Full Text Available Measures of allele and haplotype diversity, which are fundamental properties in population genetics, often follow heavy tailed distributions. These measures are of particular interest in the field of hematopoietic stem cell transplant (HSCT. Donor/Recipient suitability for HSCT is determined by Human Leukocyte Antigen (HLA similarity. Match predictions rely upon a precise description of HLA diversity, yet classical estimates are inaccurate given the heavy-tailed nature of the distribution. This directly affects HSCT matching and diversity measures in broader fields such as species richness. We, therefore, have developed a power-law based estimator to measure allele and haplotype diversity that accommodates heavy tails using the concepts of regular variation and occupancy distributions. Application of our estimator to 6.59 million donors in the Be The Match Registry revealed that haplotypes follow a heavy tail distribution across all ethnicities: for example, 44.65% of the European American haplotypes are represented by only 1 individual. Indeed, our discovery rate of all U.S. European American haplotypes is estimated at 23.45% based upon sampling 3.97% of the population, leaving a large number of unobserved haplotypes. Population coverage, however, is much higher at 99.4% given that 90% of European Americans carry one of the 4.5% most frequent haplotypes. Alleles were found to be less diverse suggesting the current registry represents most alleles in the population. Thus, for HSCT registries, haplotype discovery will remain high with continued recruitment to a very deep level of sampling, but population coverage will not. Finally, we compared the convergence of our power-law versus classical diversity estimators such as Capture recapture, Chao, ACE and Jackknife methods. When fit to the haplotype data, our estimator displayed favorable properties in terms of convergence (with respect to sampling depth and accuracy (with respect to diversity

  10. Heavy-tailed distribution of the SSH Brute-force attack duration in a multi-user environment

    Science.gov (United States)

    Lee, Jae-Kook; Kim, Sung-Jun; Park, Chan Yeol; Hong, Taeyoung; Chae, Huiseung

    2016-07-01

    Quite a number of cyber-attacks to be place against supercomputers that provide highperformance computing (HPC) services to public researcher. Particularly, although the secure shell protocol (SSH) brute-force attack is one of the traditional attack methods, it is still being used. Because stealth attacks that feign regular access may occur, they are even harder to detect. In this paper, we introduce methods to detect SSH brute-force attacks by analyzing the server's unsuccessful access logs and the firewall's drop events in a multi-user environment. Then, we analyze the durations of the SSH brute-force attacks that are detected by applying these methods. The results of an analysis of about 10 thousands attack source IP addresses show that the behaviors of abnormal users using SSH brute-force attacks are based on human dynamic characteristics of a typical heavy-tailed distribution.

  11. An EM Algorithm for Double-Pareto-Lognormal Generalized Linear Model Applied to Heavy-Tailed Insurance Claims

    Directory of Open Access Journals (Sweden)

    Enrique Calderín-Ojeda

    2017-11-01

    Full Text Available Generalized linear models might not be appropriate when the probability of extreme events is higher than that implied by the normal distribution. Extending the method for estimating the parameters of a double Pareto lognormal distribution (DPLN in Reed and Jorgensen (2004, we develop an EM algorithm for the heavy-tailed Double-Pareto-lognormal generalized linear model. The DPLN distribution is obtained as a mixture of a lognormal distribution with a double Pareto distribution. In this paper the associated generalized linear model has the location parameter equal to a linear predictor which is used to model insurance claim amounts for various data sets. The performance is compared with those of the generalized beta (of the second kind and lognorma distributions.

  12. Queueing systems with heavy tails (Summary of Ph.D. thesis on the occasion of receiving the Gijs de Leve prize)

    NARCIS (Netherlands)

    Zwart, A.P.

    2003-01-01

    This article gives a short summary of my PhD thesis Queueing Systems with Heavy-tails, winner of the Gijs De Leve prize for the best Dutch thesis in operations research in the period 2000-2002. Apart from the Gijs de Leve prize, this thesis also received the ASML prize, for best thesis in Ihe

  13. Quantification of deviations from rationality with heavy tails in human dynamics

    Science.gov (United States)

    Maillart, T.; Sornette, D.; Frei, S.; Duebendorfer, T.; Saichev, A.

    2011-05-01

    The dynamics of technological, economic and social phenomena is controlled by how humans organize their daily tasks in response to both endogenous and exogenous stimulations. Queueing theory is believed to provide a generic answer to account for the often observed power-law distributions of waiting times before a task is fulfilled. However, the general validity of the power law and the nature of other regimes remain unsettled. Using anonymized data collected by Google at the World Wide Web level, we identify the existence of several additional regimes characterizing the time required for a population of Internet users to execute a given task after receiving a message. Depending on the under- or over-utilization of time by the population of users and the strength of their response to perturbations, the pure power law is found to be coextensive with an exponential regime (tasks are performed without too much delay) and with a crossover to an asymptotic plateau (some tasks are never performed).

  14. Fine-Tuning Nonhomogeneous Regression for Probabilistic Precipitation Forecasts: Unanimous Predictions, Heavy Tails, and Link Functions

    DEFF Research Database (Denmark)

    Gebetsberger, Manuel; Messner, Jakob W.; Mayr, Georg J.

    2017-01-01

    functions for the optimization of regression coefficients for the scale parameter. These three refinements are tested for 10 stations in a small area of the European Alps for lead times from +24 to +144 h and accumulation periods of 24 and 6 h. Together, they improve probabilistic forecasts...... to obtain automatically corrected weather forecasts. This study applies the nonhomogenous regression framework as a state-of-the-art ensemble postprocessing technique to predict a full forecast distribution and improves its forecast performance with three statistical refinements. First of all, a novel split...... for precipitation amounts as well as the probability of precipitation events over the default postprocessing method. The improvements are largest for the shorter accumulation periods and shorter lead times, where the information of unanimous ensemble predictions is more important....

  15. Robust sequential learning of feedforward neural networks in the presence of heavy-tailed noise.

    Science.gov (United States)

    Vuković, Najdan; Miljković, Zoran

    2015-03-01

    Feedforward neural networks (FFNN) are among the most used neural networks for modeling of various nonlinear problems in engineering. In sequential and especially real time processing all neural networks models fail when faced with outliers. Outliers are found across a wide range of engineering problems. Recent research results in the field have shown that to avoid overfitting or divergence of the model, new approach is needed especially if FFNN is to run sequentially or in real time. To accommodate limitations of FFNN when training data contains a certain number of outliers, this paper presents new learning algorithm based on improvement of conventional extended Kalman filter (EKF). Extended Kalman filter robust to outliers (EKF-OR) is probabilistic generative model in which measurement noise covariance is not constant; the sequence of noise measurement covariance is modeled as stochastic process over the set of symmetric positive-definite matrices in which prior is modeled as inverse Wishart distribution. In each iteration EKF-OR simultaneously estimates noise estimates and current best estimate of FFNN parameters. Bayesian framework enables one to mathematically derive expressions, while analytical intractability of the Bayes' update step is solved by using structured variational approximation. All mathematical expressions in the paper are derived using the first principles. Extensive experimental study shows that FFNN trained with developed learning algorithm, achieves low prediction error and good generalization quality regardless of outliers' presence in training data. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Interconnected Risk Contributions: A Heavy-Tail Approach to Analyze U.S. Financial Sectors

    Directory of Open Access Journals (Sweden)

    Mauro Bernardi

    2015-04-01

    Full Text Available This paper investigates the dynamic evolution of tail risk interdependence among U.S. banks, financial services and insurance sectors. Life and non-life insurers have been considered separately to account for their different characteristics. The tail risk interdependence measurement framework relies on the multivariate Student-t Markov switching (MS model and the multiple-conditional value-at-risk (CoVaR (conditional expected shortfall (CoES risk measures introduced in Bernardi et al. (2013, accounting for both the stylized facts of financial data and the contemporaneous multiple joint distress events. The Shapley value methodology is then applied to compose the puzzle of individual risk attributions, providing a synthetic measure of tail interdependence. Our empirical investigation finds that banks appear to contribute more to the tail risk evolution of all of the remaining sectors, followed by the financial services and the insurance sectors, showing that the insurance sector significantly contributes as well to the overall risk. We also find that the role of each sector in contributing to other sectors’ distress evolves over time according to the current predominant financial condition, implying different interdependence strength.

  17. Heavy tails of OLS

    DEFF Research Database (Denmark)

    Mikosch, Thomas Valentin; de Vries, Casper

    2013-01-01

    Suppose the tails of the noise distribution in a regression exhibit power law behavior. Then the distribution of the OLS regression estimator inherits this tail behavior. This is relevant for regressions involving financial data. We derive explicit finite sample expressions for the tail probabili...

  18. A semiparametric negative binomial generalized linear model for modeling over-dispersed count data with a heavy tail: Characteristics and applications to crash data.

    Science.gov (United States)

    Shirazi, Mohammadali; Lord, Dominique; Dhavala, Soma Sekhar; Geedipally, Srinivas Reddy

    2016-06-01

    Crash data can often be characterized by over-dispersion, heavy (long) tail and many observations with the value zero. Over the last few years, a small number of researchers have started developing and applying novel and innovative multi-parameter models to analyze such data. These multi-parameter models have been proposed for overcoming the limitations of the traditional negative binomial (NB) model, which cannot handle this kind of data efficiently. The research documented in this paper continues the work related to multi-parameter models. The objective of this paper is to document the development and application of a flexible NB generalized linear model with randomly distributed mixed effects characterized by the Dirichlet process (NB-DP) to model crash data. The objective of the study was accomplished using two datasets. The new model was compared to the NB and the recently introduced model based on the mixture of the NB and Lindley (NB-L) distributions. Overall, the research study shows that the NB-DP model offers a better performance than the NB model once data are over-dispersed and have a heavy tail. The NB-DP performed better than the NB-L when the dataset has a heavy tail, but a smaller percentage of zeros. However, both models performed similarly when the dataset contained a large amount of zeros. In addition to a greater flexibility, the NB-DP provides a clustering by-product that allows the safety analyst to better understand the characteristics of the data, such as the identification of outliers and sources of dispersion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Efecto del uso de tiempos de atención heavy-tailed sobre el modelo básico de líneas de espera y sus medidas de desempeño

    Directory of Open Access Journals (Sweden)

    Lina M. Rangel Martínez

    2010-05-01

    Full Text Available La reciente aparición de modelos generatrices de líneas de espera con tiempos de atención heavy-tailed y su comprobación empírica implican la necesidad de conocer el comportamiento de las medidas clásicas de desempeño de una línea de espera bajo estas condiciones. El objetivo del estudio fue el de analizar el comportamiento de Lq (longitud promedio de la fila y Wq (tiempo promedio de espera en fila variando los parámetros capacidad del sistema, nivel de utilización promedio ( ρ y número de servidores para líneas de espera con tiempos de atención heavy-tailed, y contrastar dicho comportamiento con los resultados clásicos basados en procesos de Poisson, usando para ello la simulación de eventos discretos. Los resultados mostraron que la sensibilidad de los modelos con tiempos de atención heavy-tailed a variaciones en los parámetros es mayor que la de los modelos basados en procesos de Poisson. En particular, a partir de capacidades de sistema de 1.000 entidades ciertos procesos heay-tailed pueden considerarse infinitos, y la importancia del número de servidores es mayor en los procesos heavy-tailed analizados que en los procesos de Poisson. Por último, la utilización de Lq y Wq como medidas de desempeño es inadecuada para tiempos de atención heavy-tailed al generar resultados inestables y contraintuitivos.

  20. New Frontiers in Characterization of Sub-Catalog Microseismicity: Utilizing Inter-Event Waveform Cross Correlation for Estimating Precise Locations, Magnitudes, and Focal Mechanisms of Tiny Earthquakes

    Science.gov (United States)

    Ellsworth, W. L.; Shelly, D. R.; Hardebeck, J.; Hill, D. P.

    2017-12-01

    Microseismicity often conveys the most direct information about active processes in the earth's subsurface. However, routine network processing typically leaves most earthquakes uncharacterized. These "sub-catalog" events can provide critical clues to ongoing processes in the source region. To address this issue, we have developed waveform-based processing that leverages the existing routine catalog of earthquakes to detect and characterize "sub-catalog" events (those absent in routine catalogs). By correlating waveforms of cataloged events with the continuous data stream, we 1) identify events with similar waveform signatures in the continuous data across multiple stations, 2) precisely measure relative time lags across these stations for both P- and S-wave time windows, and 3) estimate the relative polarity between events by the sign of the peak absolute value correlations and its height above the secondary peak. When combined, these inter-event comparisons yield robust measurements, which enable sensitive event detection, relative relocation, and relative magnitude estimation. The most recent addition, focal mechanisms derived from correlation-based relative polarities, addresses a significant shortcoming in microseismicity analyses (see Shelly et al., JGR, 2016). Depending on the application, we can characterize 2-10 times as many events as included in the initial catalog. This technique is particularly well suited for compact zones of active seismicity such as seismic swarms. Application to a 2014 swarm in Long Valley Caldera, California, illuminates complex patterns of faulting that would have otherwise remained obscured. The prevalence of such features in other environments remains an important, as yet unresolved, question.

  1. Portfolio selection with heavy tails

    NARCIS (Netherlands)

    Hyung, N.; Vries, de C.G.

    2007-01-01

    Consider the portfolio problem of choosing the mix between stocks and bonds under a downside risk constraint. Typically stock returns exhibit fatter tails than bonds corresponding to their greater downside risk. Downside risk criteria like the safety first criterion therefore often select corner

  2. Portfolio Selection with Heavy Tails

    NARCIS (Netherlands)

    N. Hyung (Namwon); C.G. de Vries (Casper)

    2004-01-01

    textabstractConsider the portfolio problem of choosing the mix between stocks and bonds under a downside risk constraint. Typically stock returns exhibit fatter tails than bonds corresponding to their greater downside risk. Downside risk criteria like the safety first criterion therefore of ten

  3. Efecto del uso de tiempos de atención heavy-tailed sobre el modelo básico de líneas de espera y sus medidas de desempeño

    OpenAIRE

    Lina M. Rangel Martínez; Jorge A. Alvarado Valencia

    2010-01-01

    La reciente aparición de modelos generatrices de líneas de espera con tiempos de atención heavy-tailed y su comprobación empírica implican la necesidad de conocer el comportamiento de las medidas clásicas de desempeño de una línea de espera bajo estas condiciones. El objetivo del estudio fue el de analizar el comportamiento de Lq (longitud promedio de la fila) y Wq (tiempo promedio de espera en fila) variando los parámetros capacidad del sistema, nivel de utilización promedio ( ρ ) y número d...

  4. Thin and heavy tails in stochastic programming

    Czech Academy of Sciences Publication Activity Database

    Kaňková, Vlasta; Houda, Michal

    2015-01-01

    Roč. 51, č. 3 (2015), s. 433-456 ISSN 0023-5954 R&D Projects: GA ČR GA13-14445S Institutional support: RVO:67985556 Keywords : stochastic programming problems * stability * Wasserstein metric * L1 norm * Lipschitz property * empirical estimates * convergence rate * linear and nonlinear dependence * probability and risk constraints * stochastic dominance Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.628, year: 2015 http://library.utia.cas.cz/separaty/2015/E/kankova-0447994.pdf

  5. The heavy tail of the human brain

    NARCIS (Netherlands)

    Roberts, J.A.; Boonstra, T.W.; Breakspear, M.

    2015-01-01

    Fluctuating oscillations are a ubiquitous feature of neurophysiology. Are the amplitude fluctuations of neural oscillations chance excursions drawn randomly from a normal distribution, or do they tell us more? Recent empirical research suggests that the occurrence of 'anomalous' (high amplitude)

  6. Precise large deviations of aggregate claims in a size-dependent renewal risk model with stopping time claim-number process

    Directory of Open Access Journals (Sweden)

    Shuo Zhang

    2017-04-01

    Full Text Available Abstract In this paper, we consider a size-dependent renewal risk model with stopping time claim-number process. In this model, we do not make any assumption on the dependence structure of claim sizes and inter-arrival times. We study large deviations of the aggregate amount of claims. For the subexponential heavy-tailed case, we obtain a precise large-deviation formula; our method substantially relies on a martingale for the structure of our models.

  7. Univariate Lp and ɭ p Averaging, 0 < p < 1, in Polynomial Time by Utilization of Statistical Structure

    Directory of Open Access Journals (Sweden)

    John E. Lavery

    2012-10-01

    Full Text Available We present evidence that one can calculate generically combinatorially expensive Lp and lp averages, 0 < p < 1, in polynomial time by restricting the data to come from a wide class of statistical distributions. Our approach differs from the approaches in the previous literature, which are based on a priori sparsity requirements or on accepting a local minimum as a replacement for a global minimum. The functionals by which Lp averages are calculated are not convex but are radially monotonic and the functionals by which lp averages are calculated are nearly so, which are the keys to solvability in polynomial time. Analytical results for symmetric, radially monotonic univariate distributions are presented. An algorithm for univariate lp averaging is presented. Computational results for a Gaussian distribution, a class of symmetric heavy-tailed distributions and a class of asymmetric heavy-tailed distributions are presented. Many phenomena in human-based areas are increasingly known to be represented by data that have large numbers of outliers and belong to very heavy-tailed distributions. When tails of distributions are so heavy that even medians (L1 and l1 averages do not exist, one needs to consider using lp minimization principles with 0 < p < 1.

  8. Asymptotic behavior of total times For jobs that must start over if a failure occurs

    DEFF Research Database (Denmark)

    Asmussen, Søren; Fiorini, Pierre; Lipsky, Lester

    the ready queue, or it may restart the task. The behavior of systems under the first two scenarios is well documented, but the third (RESTART) has resisted detailed analysis. In this paper we derive tight asymptotic relations between the distribution of task times without failures to the total time when...... including failures, for any failure distribution. In particular, we show that if the task time distribution has an unbounded support then the total time distribution H is always heavy-tailed. Asymptotic expressions are given for the tail of H in various scenarios. The key ingredients of the analysis...

  9. Asymptotic behaviour of total times for jobs that must start over if a failure occurs

    DEFF Research Database (Denmark)

    Asmussen, Søren; Fiorini, Pierre; Lipsky, Lester

    2008-01-01

    the ready queue, or it may restart the task. The behavior of systems under the first two scenarios is well documented, but the third (RESTART) has resisted detailed analysis. In this paper we derive tight asymptotic relations between the distribution of task times without failures and the total time when...... including failures, for any failure distribution. In particular, we show that if the task-time distribution has an unbounded support, then the total-time distribution H is always heavy tailed. Asymptotic expressions are given for the tail of H in various scenarios. The key ingredients of the analysis...

  10. Hypothesis Testing Using Spatially Dependent Heavy Tailed Multisensor Data

    Science.gov (United States)

    2014-12-01

    has been unyielding, for which I shall be eternally grateful. v TABLE OF CONTENTS Acknowledgments v List of Tables ix List of Figures x 1 Introduction...2nd ed. New York, NY: Springer, 2009. 121 [8] M. J. Beal, N. Jojic, and H. Attias, “A graphical model for audiovisual object tracking,” IEEE

  11. On option pricing models in the presence of heavy tails

    NARCIS (Netherlands)

    Vellekoop, Michel; Nieuwenhuis, Hans

    2007-01-01

    We propose a modification of the option pricing framework derived by Borland which removes the possibilities for arbitrage within this framework. It turns out that such arbitrage possibilities arise due to an incorrect derivation of the martingale transformation in the non-Gaussian option models

  12. Importance sampling of heavy-tailed iterated random functions

    NARCIS (Netherlands)

    B. Chen (Bohan); C.H. Rhee (Chang-Han); A.P. Zwart (Bert)

    2016-01-01

    textabstractWe consider a stochastic recurrence equation of the form $Z_{n+1} = A_{n+1} Z_n+B_{n+1}$, where $\\mathbb{E}[\\log A_1]<0$, $\\mathbb{E}[\\log^+ B_1]<\\infty$ and $\\{(A_n,B_n)\\}_{n\\in\\mathbb{N}}$ is an i.i.d. sequence of positive random vectors. The stationary distribution of this Markov

  13. The Downside Risk of Heavy Tails induces Low Diversification

    NARCIS (Netherlands)

    N. Hyung (Namwon); C.G. de Vries (Casper)

    2010-01-01

    textabstractActual portfolios contain fewer stocks than are implied by standard financial analysis that balances the costs of diversification against the benefits in terms of the standard deviation of the returns. Suppose a safety first investor cares about downside risk and recognizes the heavy

  14. Extreme value theory and statistics for heavy tail data

    NARCIS (Netherlands)

    S. Caserta; C.G. de Vries (Casper)

    2003-01-01

    textabstractA scientific way of looking beyond the worst-case return is to employ statistical extreme value methods. Extreme Value Theory (EVT) shows that the probability on very large losses is eventually governed by a simple function, regardless the specific distribution that underlies the return

  15. Rainfall timing and runoff: The influence of the criterion for rain event separation

    OpenAIRE

    Molina-Sanchis, Isabel; Lázaro, Roberto; Arnau-Rosalén, Eva; Calvo-Cases, Adolfo

    2016-01-01

    Rain is not uniform in time and space in semiarid areas and its distribution is very important for the runoff process. Hydrological studies usually divide rainfall into events. However, defining rain events is complicated, and rain characteristics vary depending on how the events are delimited. Choosing a minimum inter-event time (MIT) is a commonly used criterion. Our hypothesis is that there will be an optimal MIT that explains the maximum part of the variance of the runoff, with time to ru...

  16. Effects of Network Structure, Competition and Memory Time on Social Spreading Phenomena

    Science.gov (United States)

    Gleeson, James P.; O'Sullivan, Kevin P.; Baños, Raquel A.; Moreno, Yamir

    2016-04-01

    Online social media has greatly affected the way in which we communicate with each other. However, little is known about what fundamental mechanisms drive dynamical information flow in online social systems. Here, we introduce a generative model for online sharing behavior that is analytically tractable and that can reproduce several characteristics of empirical micro-blogging data on hashtag usage, such as (time-dependent) heavy-tailed distributions of meme popularity. The presented framework constitutes a null model for social spreading phenomena that, in contrast to purely empirical studies or simulation-based models, clearly distinguishes the roles of two distinct factors affecting meme popularity: the memory time of users and the connectivity structure of the social network.

  17. Effects of Network Structure, Competition and Memory Time on Social Spreading Phenomena

    Directory of Open Access Journals (Sweden)

    James P. Gleeson

    2016-05-01

    Full Text Available Online social media has greatly affected the way in which we communicate with each other. However, little is known about what fundamental mechanisms drive dynamical information flow in online social systems. Here, we introduce a generative model for online sharing behavior that is analytically tractable and that can reproduce several characteristics of empirical micro-blogging data on hashtag usage, such as (time-dependent heavy-tailed distributions of meme popularity. The presented framework constitutes a null model for social spreading phenomena that, in contrast to purely empirical studies or simulation-based models, clearly distinguishes the roles of two distinct factors affecting meme popularity: the memory time of users and the connectivity structure of the social network.

  18. FARIMA MODELING OF SOLAR FLARE ACTIVITY FROM EMPIRICAL TIME SERIES OF SOFT X-RAY SOLAR EMISSION

    International Nuclear Information System (INIS)

    Stanislavsky, A. A.; Burnecki, K.; Magdziarz, M.; Weron, A.; Weron, K.

    2009-01-01

    A time series of soft X-ray emission observed by the Geostationary Operational Environment Satellites from 1974 to 2007 is analyzed. We show that in the solar-maximum periods the energy distribution of soft X-ray solar flares for C, M, and X classes is well described by a fractional autoregressive integrated moving average model with Pareto noise. The model incorporates two effects detected in our empirical studies. One effect is a long-term dependence (long-term memory), and another corresponds to heavy-tailed distributions. The parameters of the model: self-similarity exponent H, tail index α, and memory parameter d are statistically stable enough during the periods 1977-1981, 1988-1992, 1999-2003. However, when the solar activity tends to minimum, the parameters vary. We discuss the possible causes of this evolution and suggest a statistically justified model for predicting the solar flare activity.

  19. Continuous time random walk model with asymptotical probability density of waiting times via inverse Mittag-Leffler function

    Science.gov (United States)

    Liang, Yingjie; Chen, Wen

    2018-04-01

    The mean squared displacement (MSD) of the traditional ultraslow diffusion is a logarithmic function of time. Recently, the continuous time random walk model is employed to characterize this ultraslow diffusion dynamics by connecting the heavy-tailed logarithmic function and its variation as the asymptotical waiting time density. In this study we investigate the limiting waiting time density of a general ultraslow diffusion model via the inverse Mittag-Leffler function, whose special case includes the traditional logarithmic ultraslow diffusion model. The MSD of the general ultraslow diffusion model is analytically derived as an inverse Mittag-Leffler function, and is observed to increase even more slowly than that of the logarithmic function model. The occurrence of very long waiting time in the case of the inverse Mittag-Leffler function has the largest probability compared with the power law model and the logarithmic function model. The Monte Carlo simulations of one dimensional sample path of a single particle are also performed. The results show that the inverse Mittag-Leffler waiting time density is effective in depicting the general ultraslow random motion.

  20. Paradox-Proof Utility Functions for Heavy-Tailed Payoffs: Two Instructive Two-Envelope Problems

    Directory of Open Access Journals (Sweden)

    Michael R. Powers

    2015-01-01

    Full Text Available We identify restrictions on a decision maker’s utility function that are both necessary and sufficient to preserve dominance reasoning in each of two versions of the Two-Envelope Paradox (TEP. For the classical TEP, the utility function must satisfy a certain recurrence inequality. For the St. Petersburg TEP, the utility function must be bounded above asymptotically by a power function, which can be tightened to a constant. By determining the weakest conditions for dominance reasoning to hold, the article settles an open question in the research literature. Remarkably, neither constant-bounded utility nor finite expected utility is necessary for resolving the classical TEP; instead, finite expected utility is both necessary and sufficient for resolving the St. Petersburg TEP.

  1. Powerlaw: a Python package for analysis of heavy-tailed distributions.

    Science.gov (United States)

    Alstott, Jeff; Bullmore, Ed; Plenz, Dietmar

    2014-01-01

    Power laws are theoretically interesting probability distributions that are also frequently used to describe empirical data. In recent years, effective statistical methods for fitting power laws have been developed, but appropriate use of these techniques requires significant programming and statistical insight. In order to greatly decrease the barriers to using good statistical methods for fitting power law distributions, we developed the powerlaw Python package. This software package provides easy commands for basic fitting and statistical analysis of distributions. Notably, it also seeks to support a variety of user needs by being exhaustive in the options available to the user. The source code is publicly available and easily extensible.

  2. Robust Modeling of Complex Systems with Heavy Tails and Long Memory

    Science.gov (United States)

    2014-07-16

    cluster model, Scandinavian Actuarial Journal , (09 2011): 0. doi: Gennady Samorodnitsky, Sami Umut Can, Thomas Mikosch. Weak convergence of the...further studies in science , mathematics, engineering or technology fields: Student Metrics This section only applies to graduating undergraduates...0.00 0.00 0.00 0.00 The number of undergraduates funded by this agreement who graduated during this period with a degree in science , mathematics

  3. Degree-degree correlations in random graphs with heavy-tailed degrees

    NARCIS (Netherlands)

    Hofstad, van der R.W.; Litvak, N.

    2014-01-01

    Mixing patterns in large self-organizing networks, such as the Internet, the World Wide Web, social, and biological networks are often characterized by degree-degree dependencies between neighboring nodes. In assortative networks, the degree-degree dependencies are positive (nodes with similar

  4. Degree-Degree Dependencies in Random Graphs with Heavy-Tailed Degrees

    NARCIS (Netherlands)

    van der Hofstad, Remco; Litvak, Nelly

    2014-01-01

    Mixing patterns in large self-organizing networks, such as the Internet, the World Wide Web, social, and biological networks are often characterized by degree-degree dependencies between neighboring nodes. In assortative networks, the degree-degree dependencies are positive (nodes with similar

  5. Powerlaw: a Python package for analysis of heavy-tailed distributions.

    Directory of Open Access Journals (Sweden)

    Jeff Alstott

    Full Text Available Power laws are theoretically interesting probability distributions that are also frequently used to describe empirical data. In recent years, effective statistical methods for fitting power laws have been developed, but appropriate use of these techniques requires significant programming and statistical insight. In order to greatly decrease the barriers to using good statistical methods for fitting power law distributions, we developed the powerlaw Python package. This software package provides easy commands for basic fitting and statistical analysis of distributions. Notably, it also seeks to support a variety of user needs by being exhaustive in the options available to the user. The source code is publicly available and easily extensible.

  6. Large deviations of heavy-tailed random sums with applications in insurance and finance

    NARCIS (Netherlands)

    Kluppelberg, C; Mikosch, T

    We prove large deviation results for the random sum S(t)=Sigma(i=1)(N(t)) X-i, t greater than or equal to 0, where (N(t))(t greater than or equal to 0) are non-negative integer-valued random variables and (X-n)(n is an element of N) are i.i.d. non-negative random Variables with common distribution

  7. Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region.

    Science.gov (United States)

    Frankenberg, C.

    2016-12-01

    Methane (CH4) impacts climate as the second strongest anthropogenic greenhouse gas and air quality by influencing tropospheric ozone levels. Space-based observations have identified the Four Corners region in the Southwest United States as an area of large CH4 enhancements. We conducted an airborne campaign in Four Corners during April 2015 with the next-generation Airborne Visible/Infrared Imaging Spectrometer (near-infrared) and Hyperspectral Thermal Emission Spectrometer (thermal infrared) imaging spectrometers to better understand the source of methane by measuring methane plumes at 1- to 3-m spatial resolution. Our analysis detected more than 250 individual methane plumes from fossil fuel harvesting, processing, and distributing infrastructures, spanning an emission range from the detection limit ˜ 2 kg/h to 5 kg/h through ˜ 5,000 kg/h. Observed sources include gas processing facilities, storage tanks, pipeline leaks, natural seeps and well pads, as well as a coal mine venting shaft. Overall, plume enhancements and inferred fluxes follow a lognormal distribution, with the top 10% emitters contributing 49 to 66% to the inferred total point source flux of 0.23 Tg/y to 0.39 Tg/y. We will summarize the campaign results and provide an overview of how airborne remote sensing can be used to detect and infer methane fluxes over widespread geographic areas and how new instrumentation could be used to perform similar observations from space.

  8. The supremuim of a negative drift random walk with dependent heavy-tailed steps

    NARCIS (Netherlands)

    Mikosch, T; Smorodnitsky, G

    Many important probabilistic models in queuing theory, insurance and finance deal with partial sums of a negative mean stationary process (a negative drift random walk), and the law of the supremum of such a process is used to calculate, depending on the context, the ruin probability, the steady

  9. Portfolio optimization for heavy-tailed assets: Extreme Risk Index vs. Markowitz

    OpenAIRE

    Mainik, Georg; Mitov, Georgi; Rüschendorf, Ludger

    2015-01-01

    Using daily returns of the S&P 500 stocks from 2001 to 2011, we perform a backtesting study of the portfolio optimization strategy based on the extreme risk index (ERI). This method uses multivariate extreme value theory to minimize the probability of large portfolio losses. With more than 400 stocks to choose from, our study seems to be the first application of extreme value techniques in portfolio management on a large scale. The primary aim of our investigation is the potential of ERI in p...

  10. Timing Interactions in Social Simulations: The Voter Model

    Science.gov (United States)

    Fernández-Gracia, Juan; Eguíluz, Víctor M.; Miguel, Maxi San

    The recent availability of huge high resolution datasets on human activities has revealed the heavy-tailed nature of the interevent time distributions. In social simulations of interacting agents the standard approach has been to use Poisson processes to update the state of the agents, which gives rise to very homogeneous activity patterns with a well defined characteristic interevent time. As a paradigmatic opinion model we investigate the voter model and review the standard update rules and propose two new update rules which are able to account for heterogeneous activity patterns. For the new update rules each node gets updated with a probability that depends on the time since the last event of the node, where an event can be an update attempt (exogenous update) or a change of state (endogenous update). We find that both update rules can give rise to power law interevent time distributions, although the endogenous one more robustly. Apart from that for the exogenous update rule and the standard update rules the voter model does not reach consensus in the infinite size limit, while for the endogenous update there exist a coarsening process that drives the system toward consensus configurations.

  11. Investigation of market efficiency and Financial Stability between S&P 500 and London Stock Exchange: Monthly and yearly Forecasting of Time Series Stock Returns using ARMA model

    Science.gov (United States)

    Rounaghi, Mohammad Mahdi; Nassir Zadeh, Farzaneh

    2016-08-01

    We investigated the presence and changes in, long memory features in the returns and volatility dynamics of S&P 500 and London Stock Exchange using ARMA model. Recently, multifractal analysis has been evolved as an important way to explain the complexity of financial markets which can hardly be described by linear methods of efficient market theory. In financial markets, the weak form of the efficient market hypothesis implies that price returns are serially uncorrelated sequences. In other words, prices should follow a random walk behavior. The random walk hypothesis is evaluated against alternatives accommodating either unifractality or multifractality. Several studies find that the return volatility of stocks tends to exhibit long-range dependence, heavy tails, and clustering. Because stochastic processes with self-similarity possess long-range dependence and heavy tails, it has been suggested that self-similar processes be employed to capture these characteristics in return volatility modeling. The present study applies monthly and yearly forecasting of Time Series Stock Returns in S&P 500 and London Stock Exchange using ARMA model. The statistical analysis of S&P 500 shows that the ARMA model for S&P 500 outperforms the London stock exchange and it is capable for predicting medium or long horizons using real known values. The statistical analysis in London Stock Exchange shows that the ARMA model for monthly stock returns outperforms the yearly. ​A comparison between S&P 500 and London Stock Exchange shows that both markets are efficient and have Financial Stability during periods of boom and bust.

  12. Time-clustering behavior of sharp fluctuation sequences in Chinese stock markets

    International Nuclear Information System (INIS)

    Yuan Ying; Zhuang Xintian; Liu Zhiying; Huang Weiqiang

    2012-01-01

    Sharp fluctuations (in particular, extreme fluctuations) of asset prices have a great impact on financial markets and risk management. Therefore, investigating the time dynamics of sharp fluctuation is a challenge in the financial fields. Using two different representations of the sharp fluctuations (inter-event times and series of counts), the time clustering behavior in the sharp fluctuation sequences of stock markets in China is studied with several statistical tools, including coefficient of variation, Allan Factor, Fano Factor as well as R/S (rescaled range) analysis. All of the empirical results indicate that the time dynamics of the sharp fluctuation sequences can be considered as a fractal process with a high degree of time-clusterization of the events. It can help us to get a better understanding of the nature and dynamics of sharp fluctuation of stock price in stock markets.

  13. Fixed recurrence and slip models better predict earthquake behavior than the time- and slip-predictable models 1: repeating earthquakes

    Science.gov (United States)

    Rubinstein, Justin L.; Ellsworth, William L.; Chen, Kate Huihsuan; Uchida, Naoki

    2012-01-01

    The behavior of individual events in repeating earthquake sequences in California, Taiwan and Japan is better predicted by a model with fixed inter-event time or fixed slip than it is by the time- and slip-predictable models for earthquake occurrence. Given that repeating earthquakes are highly regular in both inter-event time and seismic moment, the time- and slip-predictable models seem ideally suited to explain their behavior. Taken together with evidence from the companion manuscript that shows similar results for laboratory experiments we conclude that the short-term predictions of the time- and slip-predictable models should be rejected in favor of earthquake models that assume either fixed slip or fixed recurrence interval. This implies that the elastic rebound model underlying the time- and slip-predictable models offers no additional value in describing earthquake behavior in an event-to-event sense, but its value in a long-term sense cannot be determined. These models likely fail because they rely on assumptions that oversimplify the earthquake cycle. We note that the time and slip of these events is predicted quite well by fixed slip and fixed recurrence models, so in some sense they are time- and slip-predictable. While fixed recurrence and slip models better predict repeating earthquake behavior than the time- and slip-predictable models, we observe a correlation between slip and the preceding recurrence time for many repeating earthquake sequences in Parkfield, California. This correlation is not found in other regions, and the sequences with the correlative slip-predictable behavior are not distinguishable from nearby earthquake sequences that do not exhibit this behavior.

  14. Multifractal Approach to Time Clustering of Earthquakes. Application to Mt. Vesuvio Seismicity

    Science.gov (United States)

    Codano, C.; Alonzo, M. L.; Vilardo, G.

    The clustering structure of the Vesuvian earthquakes occurring is investigated by means of statistical tools: the inter-event time distribution, the running mean and the multifractal analysis. The first cannot clearly distinguish between a Poissonian process and a clustered one due to the difficulties of clearly distinguishing between an exponential distribution and a power law one. The running mean test reveals the clustering of the earthquakes, but looses information about the structure of the distribution at global scales. The multifractal approach can enlighten the clustering at small scales, while the global behaviour remains Poissonian. Subsequently the clustering of the events is interpreted in terms of diffusive processes of the stress in the earth crust.

  15. Serial Spike Time Correlations Affect Probability Distribution of Joint Spike Events.

    Science.gov (United States)

    Shahi, Mina; van Vreeswijk, Carl; Pipa, Gordon

    2016-01-01

    Detecting the existence of temporally coordinated spiking activity, and its role in information processing in the cortex, has remained a major challenge for neuroscience research. Different methods and approaches have been suggested to test whether the observed synchronized events are significantly different from those expected by chance. To analyze the simultaneous spike trains for precise spike correlation, these methods typically model the spike trains as a Poisson process implying that the generation of each spike is independent of all the other spikes. However, studies have shown that neural spike trains exhibit dependence among spike sequences, such as the absolute and relative refractory periods which govern the spike probability of the oncoming action potential based on the time of the last spike, or the bursting behavior, which is characterized by short epochs of rapid action potentials, followed by longer episodes of silence. Here we investigate non-renewal processes with the inter-spike interval distribution model that incorporates spike-history dependence of individual neurons. For that, we use the Monte Carlo method to estimate the full shape of the coincidence count distribution and to generate false positives for coincidence detection. The results show that compared to the distributions based on homogeneous Poisson processes, and also non-Poisson processes, the width of the distribution of joint spike events changes. Non-renewal processes can lead to both heavy tailed or narrow coincidence distribution. We conclude that small differences in the exact autostructure of the point process can cause large differences in the width of a coincidence distribution. Therefore, manipulations of the autostructure for the estimation of significance of joint spike events seem to be inadequate.

  16. Estimation of the value-at-risk parameter: Econometric analysis and the extreme value theory approach

    Directory of Open Access Journals (Sweden)

    Mladenović Zorica

    2006-01-01

    Full Text Available In this paper different aspects of value-at-risk estimation are considered. Daily returns of CISCO, INTEL and NASDAQ stock indices are analyzed for period: September 1996 - September 2006. Methods that incorporate time varying variability and heavy tails of the empirical distributions of returns are implemented. The main finding of the paper is that standard econometric methods underestimate the value-at-risk parameter if heavy tails of the empirical distribution are not explicitly taken into account. .

  17. Interevent Time Distribution of Renewal Point Process, Case Study: Extreme Rainfall in South Sulawesi

    Science.gov (United States)

    Sunusi, Nurtiti

    2018-03-01

    The study of time distribution of occurrences of extreme rain phenomena plays a very important role in the analysis and weather forecast in an area. The timing of extreme rainfall is difficult to predict because its occurrence is random. This paper aims to determine the inter event time distribution of extreme rain events and minimum waiting time until the occurrence of next extreme event through a point process approach. The phenomenon of extreme rain events over a given period of time is following a renewal process in which the time for events is a random variable τ. The distribution of random variable τ is assumed to be a Pareto, Log Normal, and Gamma. To estimate model parameters, a moment method is used. Consider Rt as the time of the last extreme rain event at one location is the time difference since the last extreme rainfall event. if there are no extreme rain events up to t 0, there will be an opportunity for extreme rainfall events at (t 0, t 0 + δt 0). Furthermore from the three models reviewed, the minimum waiting time until the next extreme rainfall will be determined. The result shows that Log Nrmal model is better than Pareto and Gamma model for predicting the next extreme rainfall in South Sulawesi while the Pareto model can not be used.

  18. Power laws and self-organized criticality in theory and nature

    Energy Technology Data Exchange (ETDEWEB)

    Marković, Dimitrije, E-mail: markovic@cbs.mpg.de [Institute for Theoretical Physics, Goethe University Frankfurt (Germany); Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig (Germany); Biomagnetic Center, Hans Berger Clinic for Neurology, University Hospital Jena, Jena (Germany); Gros, Claudius, E-mail: gros@itp.uni-frankfurt.de [Institute for Theoretical Physics, Goethe University Frankfurt (Germany)

    2014-03-01

    Power laws and distributions with heavy tails are common features of many complex systems. Examples are the distribution of earthquake magnitudes, solar flare intensities and the sizes of neuronal avalanches. Previously, researchers surmised that a single general concept may act as an underlying generative mechanism, with the theory of self organized criticality being a weighty contender. The power-law scaling observed in the primary statistical analysis is an important, but by far not the only feature characterizing experimental data. The scaling function, the distribution of energy fluctuations, the distribution of inter-event waiting times, and other higher order spatial and temporal correlations, have seen increased consideration over the last years. Leading to realization that basic models, like the original sandpile model, are often insufficient to adequately describe the complexity of real-world systems with power-law distribution. Consequently, a substantial amount of effort has gone into developing new and extended models and, hitherto, three classes of models have emerged. The first line of models is based on a separation between the time scales of an external drive and an internal dissipation, and includes the original sandpile model and its extensions, like the dissipative earthquake model. Within this approach the steady state is close to criticality in terms of an absorbing phase transition. The second line of models is based on external drives and internal dynamics competing on similar time scales and includes the coherent noise model, which has a non-critical steady state characterized by heavy-tailed distributions. The third line of models proposes a non-critical self-organizing state, being guided by an optimization principle, such as the concept of highly optimized tolerance. We present a comparative overview regarding distinct modeling approaches together with a discussion of their potential relevance as underlying generative models for real

  19. Power laws and self-organized criticality in theory and nature

    International Nuclear Information System (INIS)

    Marković, Dimitrije; Gros, Claudius

    2014-01-01

    Power laws and distributions with heavy tails are common features of many complex systems. Examples are the distribution of earthquake magnitudes, solar flare intensities and the sizes of neuronal avalanches. Previously, researchers surmised that a single general concept may act as an underlying generative mechanism, with the theory of self organized criticality being a weighty contender. The power-law scaling observed in the primary statistical analysis is an important, but by far not the only feature characterizing experimental data. The scaling function, the distribution of energy fluctuations, the distribution of inter-event waiting times, and other higher order spatial and temporal correlations, have seen increased consideration over the last years. Leading to realization that basic models, like the original sandpile model, are often insufficient to adequately describe the complexity of real-world systems with power-law distribution. Consequently, a substantial amount of effort has gone into developing new and extended models and, hitherto, three classes of models have emerged. The first line of models is based on a separation between the time scales of an external drive and an internal dissipation, and includes the original sandpile model and its extensions, like the dissipative earthquake model. Within this approach the steady state is close to criticality in terms of an absorbing phase transition. The second line of models is based on external drives and internal dynamics competing on similar time scales and includes the coherent noise model, which has a non-critical steady state characterized by heavy-tailed distributions. The third line of models proposes a non-critical self-organizing state, being guided by an optimization principle, such as the concept of highly optimized tolerance. We present a comparative overview regarding distinct modeling approaches together with a discussion of their potential relevance as underlying generative models for real

  20. Analyzing time-ordered event data with missed observations.

    Science.gov (United States)

    Dokter, Adriaan M; van Loon, E Emiel; Fokkema, Wimke; Lameris, Thomas K; Nolet, Bart A; van der Jeugd, Henk P

    2017-09-01

    A common problem with observational datasets is that not all events of interest may be detected. For example, observing animals in the wild can difficult when animals move, hide, or cannot be closely approached. We consider time series of events recorded in conditions where events are occasionally missed by observers or observational devices. These time series are not restricted to behavioral protocols, but can be any cyclic or recurring process where discrete outcomes are observed. Undetected events cause biased inferences on the process of interest, and statistical analyses are needed that can identify and correct the compromised detection processes. Missed observations in time series lead to observed time intervals between events at multiples of the true inter-event time, which conveys information on their detection probability. We derive the theoretical probability density function for observed intervals between events that includes a probability of missed detection. Methodology and software tools are provided for analysis of event data with potential observation bias and its removal. The methodology was applied to simulation data and a case study of defecation rate estimation in geese, which is commonly used to estimate their digestive throughput and energetic uptake, or to calculate goose usage of a feeding site from dropping density. Simulations indicate that at a moderate chance to miss arrival events ( p  = 0.3), uncorrected arrival intervals were biased upward by up to a factor 3, while parameter values corrected for missed observations were within 1% of their true simulated value. A field case study shows that not accounting for missed observations leads to substantial underestimates of the true defecation rate in geese, and spurious rate differences between sites, which are introduced by differences in observational conditions. These results show that the derived methodology can be used to effectively remove observational biases in time-ordered event

  1. Transfer Entropy Estimation and Directional Coupling Change Detection in Biomedical Time Series

    Directory of Open Access Journals (Sweden)

    Lee Joon

    2012-04-01

    Full Text Available Abstract Background The detection of change in magnitude of directional coupling between two non-linear time series is a common subject of interest in the biomedical domain, including studies involving the respiratory chemoreflex system. Although transfer entropy is a useful tool in this avenue, no study to date has investigated how different transfer entropy estimation methods perform in typical biomedical applications featuring small sample size and presence of outliers. Methods With respect to detection of increased coupling strength, we compared three transfer entropy estimation techniques using both simulated time series and respiratory recordings from lambs. The following estimation methods were analyzed: fixed-binning with ranking, kernel density estimation (KDE, and the Darbellay-Vajda (D-V adaptive partitioning algorithm extended to three dimensions. In the simulated experiment, sample size was varied from 50 to 200, while coupling strength was increased. In order to introduce outliers, the heavy-tailed Laplace distribution was utilized. In the lamb experiment, the objective was to detect increased respiratory-related chemosensitivity to O2 and CO2 induced by a drug, domperidone. Specifically, the separate influence of end-tidal PO2 and PCO2 on minute ventilation (V˙E before and after administration of domperidone was analyzed. Results In the simulation, KDE detected increased coupling strength at the lowest SNR among the three methods. In the lamb experiment, D-V partitioning resulted in the statistically strongest increase in transfer entropy post-domperidone for PO2→V˙E. In addition, D-V partitioning was the only method that could detect an increase in transfer entropy for PCO2→V˙E, in agreement with experimental findings. Conclusions Transfer entropy is capable of detecting directional coupling changes in non-linear biomedical time series analysis featuring a small number of observations and presence of outliers. The results

  2. Bayesian deterministic decision making: A normative account of the operant matching law and heavy-tailed reward history dependency of choices

    Directory of Open Access Journals (Sweden)

    Hiroshi eSaito

    2014-03-01

    Full Text Available The decision making behaviors of humans and animals adapt and then satisfy an ``operant matching law'' in certain type of tasks. This was first pointed out by Herrnstein in his foraging experiments on pigeons. The matching law has been one landmark for elucidating the underlying processes of decision making and its learning in the brain. An interesting question is whether decisions are made deterministically or probabilistically. Conventional learning models of the matching law are based on the latter idea; they assume that subjects learn choice probabilities of respective alternatives and decide stochastically with the probabilities. However, it is unknown whether the matching law can be accounted for by a deterministic strategy or not. To answer this question, we propose several deterministic Bayesian decision making models that have certain incorrect beliefs about an environment. We claim that a simple model produces behavior satisfying the matching law in static settings of a foraging task but not in dynamic settings. We found that the model that has a belief that the environment is volatile works well in the dynamic foraging task and exhibits undermatching, which is a slight deviation from the matching law observed in many experiments. This model also demonstrates the double-exponential reward history dependency of a choice and a heavier-tailed run-length distribution, as has recently been reported in experiments on monkeys.

  3. A continuous time random walk model for Darcy-scale anomalous transport in heterogeneous porous media.

    Science.gov (United States)

    Comolli, Alessandro; Hakoun, Vivien; Dentz, Marco

    2017-04-01

    Achieving the understanding of the process of solute transport in heterogeneous porous media is of crucial importance for several environmental and social purposes, ranging from aquifers contamination and remediation, to risk assessment in nuclear waste repositories. The complexity of this aim is mainly ascribable to the heterogeneity of natural media, which can be observed at all the scales of interest, from pore scale to catchment scale. In fact, the intrinsic heterogeneity of porous media is responsible for the arising of the well-known non-Fickian footprints of transport, including heavy-tailed breakthrough curves, non-Gaussian spatial density profiles and the non-linear growth of the mean squared displacement. Several studies investigated the processes through which heterogeneity impacts the transport properties, which include local modifications to the advective-dispersive motion of solutes, mass exchanges between some mobile and immobile phases (e.g. sorption/desorption reactions or diffusion into solid matrix) and spatial correlation of the flow field. In the last decades, the continuous time random walk (CTRW) model has often been used to describe solute transport in heterogenous conditions and to quantify the impact of point heterogeneity, spatial correlation and mass transfer on the average transport properties [1]. Open issues regarding this approach are the possibility to relate measurable properties of the medium to the parameters of the model, as well as its capability to provide predictive information. In a recent work [2] the authors have shed new light on understanding the relationship between Lagrangian and Eulerian dynamics as well as on their evolution from arbitrary initial conditions. On the basis of these results, we derive a CTRW model for the description of Darcy-scale transport in d-dimensional media characterized by spatially random permeability fields. The CTRW approach models particle velocities as a spatial Markov process, which is

  4. Time over time

    Directory of Open Access Journals (Sweden)

    Vicente Navarro, Eduardo

    2006-05-01

    Full Text Available The present essay is designed to be a general introduction to the philosophical problem of time from its very different forms and ways of approaching. In this sense, the article covers the problem from different perspectives and gives a brief account of the plurality and diversity of the time found in the different philosophical definitions, in the different layers of knowledge, in different periods and cultures and also in the different instruments used to measure time itself

  5. Old times Old times

    Directory of Open Access Journals (Sweden)

    Ubiratan Paiva de Oliveira

    2008-04-01

    Full Text Available In Pinter: A Study of His Plays, Martin Esslin mentions three levels of possible interpretation for Old Times. According to him, Pinter's play could be interpreted on a realistic level, or either representing the male character's dream or a ritual game. He correctly remarks, though, that none of those levels excludes the others, because "... they must co-exist to create the atmosphere of poetic ambivalence on which the image of the play rests..1 In Pinter: A Study of His Plays, Martin Esslin mentions three levels of possible interpretation for Old Times. According to him, Pinter's play could be interpreted on a realistic level, or either representing the male character's dream or a ritual game. He correctly remarks, though, that none of those levels excludes the others, because "... they must co-exist to create the atmosphere of poetic ambivalence on which the image of the play rests..1

  6. Old times Old times

    OpenAIRE

    Ubiratan Paiva de Oliveira

    2008-01-01

    In Pinter: A Study of His Plays, Martin Esslin mentions three levels of possible interpretation for Old Times. According to him, Pinter's play could be interpreted on a realistic level, or either representing the male character's dream or a ritual game. He correctly remarks, though, that none of those levels excludes the others, because "... they must co-exist to create the atmosphere of poetic ambivalence on which the image of the play rests..1 In Pinter: A Study of His Plays, Martin Esslin ...

  7. Timing of Late Holocene surface rupture of the Wairau Fault, Marlborough, New Zealand

    International Nuclear Information System (INIS)

    Zachariasen, J.; Berryman, K.R.; Langridge, R.M.; Prentice, C.; Rymer, M.; Stirling, M.W.; Villamor, P.

    2006-01-01

    Three trenches excavated across the central portion of the right-lateral strike-slip Wairau Fault in South Island, New Zealand, exposed a complex set of fault strands that have displaced a sequence of late Holocene alluvial and colluvial deposits. Abundant charcoal fragments provide age control for various stratigraphic horizons dating back to c. 5610 yr ago. Faulting relations from the Wadsworth trench show that the most recent surface rupture event occurred at least 1290 yr and at most 2740 yr ago. Drowned trees in landslide-dammed Lake Chalice, in combination with charcoal from the base of an unfaulted colluvial wedge at Wadsworth trench, suggest a narrower time bracket for this event of 1811-2301 cal. yr BP. The penultimate faulting event occurred between c. 2370 and 3380 yr, and possibly near 2680 ± 60 cal. yr BP, when data from both the Wadsworth and Dillon trenches are combined. Two older events have been recognised from Dillon trench but remain poorly dated. A probable elapsed time of at least 1811 yr since the last surface rupture, and an average slip rate estimate for the Wairau Fault of 3-5 mm/yr, suggests that at least 5.4 m and up to 11.5 m of elastic shear strain has accumulated since the last rupture. This is near to or greater than the single-event displacement estimates of 5-7 m. The average recurrence interval for surface rupture of the fault determined from the trench data is 1150-1400 yr. Although the uncertainties in the timing of faulting events and variability in inter-event times remain high, the time elapsed since the last event is in the order of 1-2 times the average recurrence interval, implying that the Wairau Fault is near the end of its interseismic period. (author). 44 refs., 10 figs., 1 tab

  8. Studing Regional Wave Source Time Functions Using A Massive Automated EGF Deconvolution Procedure

    Science.gov (United States)

    Xie, J. "; Schaff, D. P.

    2010-12-01

    Reliably estimated source time functions (STF) from high-frequency regional waveforms, such as Lg, Pn and Pg, provide important input for seismic source studies, explosion detection, and minimization of parameter trade-off in attenuation studies. The empirical Green’s function (EGF) method can be used for estimating STF, but it requires a strict recording condition. Waveforms from pairs of events that are similar in focal mechanism, but different in magnitude must be on-scale recorded on the same stations for the method to work. Searching for such waveforms can be very time consuming, particularly for regional waves that contain complex path effects and have reduced S/N ratios due to attenuation. We have developed a massive, automated procedure to conduct inter-event waveform deconvolution calculations from many candidate event pairs. The procedure automatically evaluates the “spikiness” of the deconvolutions by calculating their “sdc”, which is defined as the peak divided by the background value. The background value is calculated as the mean absolute value of the deconvolution, excluding 10 s around the source time function. When the sdc values are about 10 or higher, the deconvolutions are found to be sufficiently spiky (pulse-like), indicating similar path Green’s functions and good estimates of the STF. We have applied this automated procedure to Lg waves and full regional wavetrains from 989 M ≥ 5 events in and around China, calculating about a million deconvolutions. Of these we found about 2700 deconvolutions with sdc greater than 9, which, if having a sufficiently broad frequency band, can be used to estimate the STF of the larger events. We are currently refining our procedure, as well as the estimated STFs. We will infer the source scaling using the STFs. We will also explore the possibility that the deconvolution procedure could complement cross-correlation in a real time event-screening process.

  9. Time outs

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000756.htm Time outs To use the sharing features on this ... children, 2 to 12 years old. Why Does Time out Work? When you put children in time ...

  10. Time Operators and Time Crystals

    OpenAIRE

    Nakatsugawa, K.; Fujii, T.; Saxena, A.; Tanda, S.

    2017-01-01

    We investigate time operators in the context of quantum time crystals in ring systems. We demonstrate that a self-adjoint time operator with a periodic time evolution can be derived for a free particle on a ring system: The conventional Aharonov-Bohm time operator is obtained by taking the infinite-radius limit. We also reveal the relationship between our time operator and a $\\mathcal PT$-symmetric time operator. We find that both time operators indeed describe the periodic time evolution of ...

  11. Time-out/Time-in

    DEFF Research Database (Denmark)

    Bødker, Mads; Gimpel, Gregory; Hedman, Jonas

    2014-01-01

    time-in and time-out use. Time-in technology use coincides and co-exists within the flow of ordinary life, while time-out use entails ‘taking time out’ of everyday life to accomplish a circumscribed task or engage reflectively in a particular experience. We apply a theoretically informed grounded...

  12. Amplitude and Recurrence Time of LP activity at Mt. Etna, Italy

    Science.gov (United States)

    Cauchie, Léna; Saccorotti, Gilberto; Bean, Christopher

    2013-04-01

    , similar for both families, differ instead significantly from the Gutenberg-Richter law, and the inter-event times distributions don't follow a typical Gamma-law. In order to compare these results with a catalogue for which the source mechanism is well-established, we applied the same analysis procedure to a dataset from Stromboli Volcano, where LP activity is closely related to VLP (Very-Long-Period) pulses, in turn associated with the summit explosions. Again, catalogues of thousands of LP events were achieved over one month of seismic records (July 2011). Our results indicate a similar behaviour in terms of both amplitude and inter-event time distributions, with respect to what observed at Mt. Etna. This suggests that the Etna's LP data are likely related with a degassing process occurring at depth. Nonetheless, further studies are needed in order to quantify the time recurrence and amplitude distribution of brittle failure in viscous, stressed magmas. Hopefully, these steps will lead to an improved understanding of LP activity in different volcanic contexts, in turn clarifying its significance in terms of eruption forecasting.

  13. Time change

    DEFF Research Database (Denmark)

    Veraart, Almut; Winkel, Matthias

    2010-01-01

    The mathematical operation of time-changing continuous-time stochastic processes can be regarded as a standard method for building financial models. We briefly review the theory on time-changed stochastic processes and relate them to stochastic volatility models in finance. Popular models......, including time-changed Lévy processes, where the time-change process is given by a subordinator or an absolutely continuous time change, are presented. Finally, we discuss the potential and the limitations of using such processes for constructing multivariate financial models....

  14. Urban Times

    DEFF Research Database (Denmark)

    Nielsen, Morten

    2017-01-01

    This is a proposed special issue with six thematic articles by different contributors on 'urban times' edited by me.......This is a proposed special issue with six thematic articles by different contributors on 'urban times' edited by me....

  15. Different Times?

    NARCIS (Netherlands)

    A. van den Broek; W.P. Knulst; K. Breedveld

    1999-01-01

    Original title: Naar andere tijden? The report Different times? Time use and time structuring in the Netherlands, 1975-1995 (Naar andere tijden? Tijdsbesteding en tijdsordening in Nederland, 1975-1995) paints a picture of the way in which the Dutch spend the 168 hours that are available each

  16. Geologic Time.

    Science.gov (United States)

    Newman, William L.

    One of a series of general interest publications on science topics, the booklet provides those interested in geologic time with an introduction to the subject. Separate sections discuss the relative time scale, major divisions in geologic time, index fossils used as guides for telling the age of rocks, the atomic scale, and the age of the earth.…

  17. Deconstructing time

    Science.gov (United States)

    Purcell, Conor

    2018-05-01

    Carlo Rovelli, best-selling author of Seven Brief Lessons on Physics, is back with a new book, The Order of Time. This latest venture offers insight into the notion of time, including narratives on how our understanding of the concept has changed from antiquity to the present, as well as a concise update on how time is understood today through the lens of quantum mechanics.

  18. Reading: Time

    NARCIS (Netherlands)

    Annemarie Wennekers; Frank Huysmans; Jos de Haan

    2018-01-01

    Original title: Lees:Tijd The amount of time that Dutch people spend reading has been declining steadily since the 1950s. This decline in reading time contrasts starkly with the positive personal and social benefits that can be derived from reading, according to lots of research. The Reading:

  19. Experiencing time

    CERN Document Server

    Prosser, Simon

    2018-01-01

    Our engagement with time is a ubiquitous feature of our lives. We are aware of time on many scales, from the briefest flicker of change to the way our lives unfold over many years. But to what extent does this encounter reveal the true nature of temporal reality? To the extent that temporal reality is as it seems, how do we come to be aware of it? And to the extent that temporal reality is not as it seems, why does it seem that way? These are the central questions addressed by Simon Prosser in Experiencing Time. These questions take on a particular importance in philosophy for two reasons. Firstly, there is a view concerning the metaphysics of time, known as the B-theory of time, according to which the apparently dynamic quality of change, the special status of the present, and even the passage of time are all illusions. Instead, the world is a four-dimensional space-time block, lacking any of the apparent dynamic features of time. If the B-theory is correct, as the book argues, then it must be explained why ...

  20. Time Management

    Science.gov (United States)

    Stoilov, Todor, Ed.

    2012-01-01

    The time management is worthy goal of many human activities. It concerns variety problems related to goals definition, assessment of available resources, control of management policies, scheduling of decisions. This book is an attempt to illustrate the decision making process in time management for different success stories, which can be used as…

  1. Spatializing Time

    DEFF Research Database (Denmark)

    Thomsen, Bodil Marie Stavning

    2011-01-01

    The article analyses some of artist Søren Lose's photographic installations in which time, history and narration is reflected in the creation of allegoric, spatial relations.......The article analyses some of artist Søren Lose's photographic installations in which time, history and narration is reflected in the creation of allegoric, spatial relations....

  2. Turnover Time

    Science.gov (United States)

    Ecosystems contain energy and materials such as carbon, nitrogen, phosphorus, and water, and are open to their flow-through. Turnover time refers to the amount of time required for replacement by flow-through of the energy or substance of interest contained in the system, and is ...

  3. Representing time

    Directory of Open Access Journals (Sweden)

    Luca Poncellini

    2010-06-01

    Full Text Available The analysis of natural phenomena applied to architectural planning and design is facing the most fascinating and elusive of the four dimensions through which man attempts to define life within the universe: time. We all know what time is, said St. Augustine, but nobody knows how to describe it. Within architectural projects and representations, time rarely appears in explicit form. This paper presents the results of a research conducted by students of NABA and of the Polytechnic of Milan with the purpose of representing time considered as a key element within architectural projects. Student investigated new approaches and methodologies to represent time using the two-dimensional support of a sheet of paper.

  4. About time

    CERN Document Server

    Frank, Adam

    2012-01-01

    From Stonehenge to beyond the Big Bang, an exhilarating scientific exploration of how we make time Time is the grandest conception of the universe that we humans have been able to imagine – and its most intimate, the very frame of human life. In About Time, astrophysicist and award-winning writer Adam Frank tells the scientific story of this wonderful and tyrannical invention. A Palaeolithic farmer moved through the sun-fuelled day and star-steered night in a radically different way than the Elizabethan merchants who set their pace to the clocks newly installed in their town squares. Since th

  5. Uniform asymptotics for compound Poisson processes with regularly varying jumps and vanishing drift

    NARCIS (Netherlands)

    Kamphorst, B.; Zwart, B.

    2015-01-01

    This paper addresses heavy-tailed asymptotics of functionals of a class of spectrally one-sided L\\'evy process that remain valid in a near-critical regime. This complements recent similar results that have been obtained for the all-time supremum of such processes. Specifically, we consider local

  6. Larmor time and proper time

    Energy Technology Data Exchange (ETDEWEB)

    Kudaka, Shoju [Department of Physics, University of the Ryukyus, Okinawa 903-0129 (Japan); Matsumoto, Shuichi, E-mail: shuichi@edu.u-ryukyu.ac.jp [Department of Mathematics, University of the Ryukyus, Okinawa 903-0129 (Japan)

    2012-10-01

    The idea of a Larmor clock is reexamined in the relativistic regime. We propose a concept of proper time for quantum theoretical particles. The Larmor clock can measure, under some relevant conditions, the proper time that passes while the particle stays in a space region. Our approach to Larmor clock is different than those of other researchers in the following two aspects: our concept of Larmor clock does not distinguish whether the particle is transmitted or reflected at the end of its stay, and pointer of our Larmor clock is not the spin but the total angular momentum. -- Highlights: ► The idea of a Larmor clock is reexamined in the relativistic regime. ► We propose a concept of proper time for quantum theoretical particles. ► The Larmor clock measures the passage of this quantum theoretical proper time.

  7. Telling time

    Directory of Open Access Journals (Sweden)

    Populizio Ivan

    2002-06-01

    Full Text Available According to Einstein’s renowned declaration, for those who believe in physics – or, more precisely, in its capability to offer a “scientific” representation of the world – the distinction between present, past and future is just “an illusion, though obstinate”. If we consider an effective analogy by Mauro Dorato, we can state that those who agree with the famous German scientist will recognize in the present, past and future a relationship very similar to that between “here” and “somewhere else” – in other words, the present is just a located moment and has no privileged status. In other conceptual universes, some of which are explored by philosophy, or imagined by art, as well as in other scientific disciplines like biology, the need for a strong distinction between “what has happened”, “what will happen” and “what is happening” seems to be unavoidable. At the macroscopic level of living beings there does not seem to be a way out of the “eternal present”, which cannot be escaped even by the desire of some well-developed mammals to understand reality or such an apparently primary experience as the “passing of time”. Even the “timeless” description of reality offered by physics is immersed in time and changes with it. This paradox seems to contain the core of the irreducibility between two cultural constructions which we will be calling “the time of the soul” and “the time of the world”, after Ricoeur. The main thesis of this essay is that there are two fundamentally different ways of facing the mystery of time, which have a precise relationship with the mentioned contrast between the subjective and the objective conception of time – mental, qualitative and experienced in the first case; physical, quantitative and measurable in the second. Considering Ricoeur’s research on time and stories, we can conclude that this dichotomy may give rise to another similarly radical difference between

  8. Timing matters

    DEFF Research Database (Denmark)

    Kothari, Ninad B.; Wohlgemuth, Melville J.; Hulgard, Katrine

    2014-01-01

    To successfully negotiate a cluttered environment, an echolocating bat must control the timing of motor behaviors in response to dynamic sensory information. Here we detail the big brown bat's adaptive temporal control over sonar call production for tracking prey, moving predictably or unpredicta...

  9. Time matters

    NARCIS (Netherlands)

    Gabbert, Silke; Hilber, Isabel

    2016-01-01

    A core aim of the European chemicals legislation REACH is to ensure that the risks caused by substances of very high concern (SVHC) are adequately controlled. Authorisation – i.e. the formal approval of certain uses of SVHC for a limited time - is a key regulatory instrument in order to achieve

  10. Timely Rubies

    DEFF Research Database (Denmark)

    Brichet, Nathalia Sofie

    2018-01-01

    Based on anthropological fieldwork in Greenland, I explore how rubies as a natural resource create and organise forms of temporality in order for the stones to appear as a valuable good. I suggest that a circular argument is at play with regard to the Greenlandic rubies, namely that time creates ...... embedded in and generated through social practices. Accordingly, time in relation to mining does not so much present a philosophical challenge, but is rather just a “thing” that happens to be good to think a Greenlandic resource landscape through – as are rubies.......Based on anthropological fieldwork in Greenland, I explore how rubies as a natural resource create and organise forms of temporality in order for the stones to appear as a valuable good. I suggest that a circular argument is at play with regard to the Greenlandic rubies, namely that time creates...... valuable rubies and rubies create time. I further argue that this interdependence is an important self-fulfilling driver in creating a viable mining industry for gemstones in Greenland. A focus on temporality enables me to engage in this circularity and thereby explore one component in the work of making...

  11. Time matters

    DEFF Research Database (Denmark)

    Andreasen, Karen Egedal; Rasmussen, Annette

    such as the PISA studies, and tendencies in educational politics and schoolsystems in Europe, USA, Australia and Asia. This spring (2011) all danish pupils in grade 6. has been tested nationally for the first time in reading skills and mathematics. The argumentation behind the initiative points to both economical...

  12. Time management

    OpenAIRE

    Hanus, Filip

    2016-01-01

    The diploma thesis applies to issues and methods of time management at work of ČSOB, a.s. managers in western area of the Czech Republic. The thesis is devided into two basic parts. First part is theoretical and methodological, second part contains of impractical research using questionnaires investigation and controlled conversation. First part of the thesis describes theoretical anchoring of the topic including methods of gathering data. Second part shortly introduces particular company and...

  13. Leisure time

    OpenAIRE

    Lušina, Barbara

    2011-01-01

    Leisure is an important part of our lives that we are left with after completing commitments - school, vocational, social, family. It is important because it gives us happiness, freedom, relaxation, helps us to feel better and allows personal growth and development. In the theoretical part well-defined leisure is presented, with its main functions, various activities, principles of exploitation and factors that affect leisure. The thesis also includes description of ranking free time in the ...

  14. Attacking Time

    Science.gov (United States)

    2015-06-01

    13 published papers , and 8 technical reports. All of these publications are available through password-protected access at: http...additional Ph.D. thesis on hardware hiding has been completed, together with an additional paper ; thesis preparation is in progress. In addition, this...employing microcontrollers and other real-time processors. These devices typically lack memory management and make little to no use of cache. • Dynamic

  15. Beijing Time

    OpenAIRE

    Dutton, Michael; Lo, Hsiu-ju Stacy; Wu, Dong Dong

    2010-01-01

    “Where is the market?” inquires the tourist one dark, chilly morning. “Follow the ghosts,” responds the taxi driver, indicating a shadowy parade of overloaded tricycles. “It’s not called the ghost market for nothing!” And indeed, Beijing is nothing if not haunted. Among the soaring skyscrapers, choking exhaust fumes, nonstop traffic jams, and towering monuments, one discovers old Beijing—newly styled, perhaps, but no less present and powerful than in its ancient incarnation. Beijing Time cond...

  16. Time Remains

    OpenAIRE

    Gryb, Sean; Thebault, Karim

    2014-01-01

    On one popular view, the general covariance of gravity implies that change is relational in a strong sense, such that all it is for a physical degree of freedom to change is for it to vary with regard to a second physical degree of freedom. At a quantum level, this view of change as relative variation leads to a fundamentally timeless formalism for quantum gravity. Here, we will show how one may avoid this acute 'problem of time'. Under our view, duration is still regarded as relative, but te...

  17. Timing collector

    CERN Document Server

    Schnell, J D

    2006-01-01

    L'unité a pour but de normaliser en signe, en largeur et en amplitude les signaux de timing destinés à être acquis par les DPRAM. Les signaux d'origine, reçus en format blocking (30V), ou TTL (logique positive ou négative) sont transmis en mode différentiel au DPRAM. En option, ils peuvent être transmis parallèlement sur un tiroir auxiliaire lequel redistribue ces signaux aux fins de tests sur son panneau avant.

  18. Cloud time

    CERN Document Server

    Lockwood, Dean

    2012-01-01

    The ‘Cloud’, hailed as a new digital commons, a utopia of collaborative expression and constant connection, actually constitutes a strategy of vitalist post-hegemonic power, which moves to dominate immanently and intensively, organizing our affective political involvements, instituting new modes of enclosure, and, crucially, colonizing the future through a new temporality of control. The virtual is often claimed as a realm of invention through which capitalism might be cracked, but it is precisely here that power now thrives. Cloud time, in service of security and profit, assumes all is knowable. We bear witness to the collapse of both past and future virtuals into a present dedicated to the exploitation of the spectres of both.

  19. Doing Time

    Science.gov (United States)

    Yang, Suzanne; Kadouri, Alane; Révah-Lévy, Anne; Mulvey, Edward P.; Falissard, Bruno

    2009-01-01

    Once convicted, the perpetrator of serious crime embarks upon a new journey: the challenge of adjusting to long-term imprisonment. Prisoners’ views of incarceration and the meaning of this experience may affect their later adjustment to life in the community. On the basis of brief narrative responses collected during an epidemiological survey of the psychological health of prisoners in France, this study examined the impact of incarceration on psychological state in a group of 59 inmates serving long sentences. Qualitative content analysis and computer-assisted linguistic analysis (using ALCESTE software) were performed on the textual data of open responses to three standard questions. Using a combination of these two approaches, seven categories of the subjective experience of prisoners in the sample were identified: the Outside World, Others, Punishment, Time, Affects and Impulses, Self-Concept, and Speech. Further qualitative analyses were then performed to compare the responses of Severely Mentally Ill (SMI) subjects and subjects with no psychiatric disorder. These analyses revealed contrasting attitudes towards incarceration. SMI subjects spoke in more hostile and persecutory terms about their experience in prison, attributing suffering to external circumstances, while subjects with no psychiatric disorder evoked similar themes, but with an introspective attitude. The themes evoked by mentally ill individuals in our sample suggest that their reactions to the prison environment arise in part from aspects of their psychiatric symptoms, and this may have relevance to future mental health policy and practices in criminal corrections. PMID:19619895

  20. Process algebra with timing : real time and discrete time

    NARCIS (Netherlands)

    Baeten, J.C.M.; Middelburg, C.A.; Bergstra, J.A.; Ponse, A.J.; Smolka, S.A.

    2001-01-01

    We present real time and discrete time versions of ACP with absolute timing and relative timing. The starting-point is a new real time version with absolute timing, called ACPsat, featuring urgent actions and a delay operator. The discrete time versions are conservative extensions of the discrete

  1. Process algebra with timing: Real time and discrete time

    NARCIS (Netherlands)

    Baeten, J.C.M.; Middelburg, C.A.

    1999-01-01

    We present real time and discrete time versions of ACP with absolute timing and relative timing. The startingpoint is a new real time version with absolute timing, called ACPsat , featuring urgent actions and a delay operator. The discrete time versions are conservative extensions of the discrete

  2. Time in contemporary cosmology

    International Nuclear Information System (INIS)

    Mavrides, Stamatia

    1980-01-01

    Cosmological time is defined, as is coordinated universal time against local times of special relativity. The problems of time and matter, age of the universe, Goedel models, arrow of time, are also discussed [fr

  3. Babies Need Tummy Time

    Science.gov (United States)

    ... sharing on social media links Babies Need Tummy Time! Page Content Tummy Time is not only an ... of your baby’s normal growth. What Is Tummy Time? Tummy Time describes the times when you place ...

  4. 'Stutter timing' for charge decay time measurement

    International Nuclear Information System (INIS)

    Chubb, John; Harbour, John; Pavey, Ian

    2011-01-01

    The paper describes the approach of 'stutter timing' that has been developed to improve the accuracy of measuring charge decay times in the presence of noise in compact and portable charge decay test instrumentation. The approach involves starting and stopping the timing clock as the noisy signal rises above and falls below the target threshold voltage level.

  5. Scheduling with time-dependent execution times

    NARCIS (Netherlands)

    Woeginger, G.J.

    1995-01-01

    We consider systems of tasks where the task execution times are time-dependent and where all tasks have some common deadline. We describe how to compute in polynomial time a schedule that minimizes the number of late tasks. This answers a question raised in a recent paper by Ho, Leung and Wei.

  6. Multiplexing real-time timed events

    NARCIS (Netherlands)

    Holenderski, M.J.; Cools, W.A.; Bril, R.J.; Lukkien, J.J.

    2009-01-01

    This paper presents the design and implementation of RELTEQ, a timed event management algorithm based on relative event times, supporting long event interarrival time, long lifetime of the event queue, no drift and low overhead. It is targeted at embedded operating systems. RELTEQ has been conceived

  7. Anomalous stress diffusion, Omori's law and Continuous Time Random Walk in the 2010 Efpalion aftershock sequence (Corinth rift, Greece)

    Science.gov (United States)

    Michas, Georgios; Vallianatos, Filippos; Karakostas, Vassilios; Papadimitriou, Eleftheria; Sammonds, Peter

    2014-05-01

    Efpalion aftershock sequence occurred in January 2010, when an M=5.5 earthquake was followed four days later by another strong event (M=5.4) and numerous aftershocks (Karakostas et al., 2012). This activity interrupted a 15 years period of low to moderate earthquake occurrence in Corinth rift, where the last major event was the 1995 Aigion earthquake (M=6.2). Coulomb stress analysis performed in previous studies (Karakostas et al., 2012; Sokos et al., 2012; Ganas et al., 2013) indicated that the second major event and most of the aftershocks were triggered due to stress transfer. The aftershocks production rate decays as a power-law with time according to the modified Omori law (Utsu et al., 1995) with an exponent larger than one for the first four days, while after the occurrence of the second strong event the exponent turns to unity. We consider the earthquake sequence as a point process in time and space and study its spatiotemporal evolution considering a Continuous Time Random Walk (CTRW) model with a joint probability density function of inter-event times and jumps between the successive earthquakes (Metzler and Klafter, 2000). Jump length distribution exhibits finite variance, whereas inter-event times scale as a q-generalized gamma distribution (Michas et al., 2013) with a long power-law tail. These properties are indicative of a subdiffusive process in terms of CTRW. Additionally, the mean square displacement of aftershocks is constant with time after the occurrence of the first event, while it changes to a power-law with exponent close to 0.15 after the second major event, illustrating a slow diffusive process. During the first four days aftershocks cluster around the epicentral area of the second major event, while after that and taking as a reference the second event, the aftershock zone is migrating slowly with time to the west near the epicentral area of the first event. This process is much slower from what would be expected from normal diffusion, a

  8. Prothrombin time (PT)

    Science.gov (United States)

    PT; Pro-time; Anticoagulant-prothrombin time; Clotting time: protime; INR; International normalized ratio ... PT is measured in seconds. Most of the time, results are given as what is called INR ( ...

  9. Real-time systems

    OpenAIRE

    Badr, Salah M.; Bruztman, Donald P.; Nelson, Michael L.; Byrnes, Ronald Benton

    1992-01-01

    This paper presents an introduction to the basic issues involved in real-time systems. Both real-time operating sys and real-time programming languages are explored. Concurrent programming and process synchronization and communication are also discussed. The real-time requirements of the Naval Postgraduate School Autonomous Under Vehicle (AUV) are then examined. Autonomous underwater vehicle (AUV), hard real-time system, real-time operating system, real-time programming language, real-time sy...

  10. Evaluating Distributed Timing Constraints

    DEFF Research Database (Denmark)

    Kristensen, C.H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems.......In this paper we describe a solution to the problem of implementing time-optimal evaluation of timing constraints in distributed real-time systems....

  11. The scaling of wild events in stochastic models: The Fisher limit, the Mandelbrot limit, and FARIMA as a model of the intermediate cases

    Science.gov (United States)

    Watkins, Nicholas

    2013-04-01

    Stochastic modelling is of increasing importance, both specifically in climate science and more broadly across the whole of nonlinear geophysics. Traditionally, the noise components of such models would be spectrally white (delta-correlated) and Gaussian in amplitude, and their variance (first named by Fisher in 1918) would well characterise the likely size of fluctuations. Integration, for example in autoregressive models like AR(1), would redden a noise spectrum, while multiplication in turbulent cascades could greatly increase the range of fluctuation amplitudes, but such processes would still inherit aspects of their finite variance building blocks. In the 60s and 70s, however, Mandelbrot and others [see e.g. Watkins, GRL Frontiers, 2013] began to present evidence in nature for much stronger departures from Gaussianity (via very heavy tailed, infinite variance, distributions) and from white noise (through long range dependence (LRD) in time). He also observed intermittency, defined here as correlations between absolute magnitudes in some time series, in, for example, finance and turbulence. He proposed various models, including self-similar ones for heavy tails and LRD, and multifractal cascades for intermittency. In this presentation we compare contrasting types of model by looking at the "wild" events that they produce. The notion of a "wild" event can be made more precise in many ways, including by its duration in time, peak amplitude, and spatial extent. Our chosen measure will be the "burst", defined as the area of a time series above a fixed threshold. We will compare burst scaling in a self-similar, LRD, heavy tailed model (LFSM, e.g. Watkins et al, PRE, 2009] with our newer results for multifractal random walks [with M. Rypdal and O. Lovsletten], and for the heavy tailed extended version of the FARIMA (1,d,0) process, which combines long range dependence with the high frequency structure familiar from AR(1). We will also discuss the physical meaning of

  12. Photonic time crystals.

    Science.gov (United States)

    Zeng, Lunwu; Xu, Jin; Wang, Chengen; Zhang, Jianhua; Zhao, Yuting; Zeng, Jing; Song, Runxia

    2017-12-07

    When space (time) translation symmetry is spontaneously broken, the space crystal (time crystal) forms; when permittivity and permeability periodically vary with space (time), the photonic crystal (photonic time crystal) forms. We proposed the concept of photonic time crystal and rewritten the Maxwell's equations. Utilizing Finite Difference Time Domain (FDTD) method, we simulated electromagnetic wave propagation in photonic time crystal and photonic space-time crystal, the simulation results show that more intensive scatter fields can obtained in photonic time crystal and photonic space-time crystal.

  13. Gap timing and the spectral timing model.

    Science.gov (United States)

    Hopson, J W

    1999-04-01

    A hypothesized mechanism underlying gap timing was implemented in the Spectral Timing Model [Grossberg, S., Schmajuk, N., 1989. Neural dynamics of adaptive timing and temporal discrimination during associative learning. Neural Netw. 2, 79-102] , a neural network timing model. The activation of the network nodes was made to decay in the absence of the timed signal, causing the model to shift its peak response time in a fashion similar to that shown in animal subjects. The model was then able to accurately simulate a parametric study of gap timing [Cabeza de Vaca, S., Brown, B., Hemmes, N., 1994. Internal clock and memory processes in aminal timing. J. Exp. Psychol.: Anim. Behav. Process. 20 (2), 184-198]. The addition of a memory decay process appears to produce the correct pattern of results in both Scalar Expectancy Theory models and in the Spectral Timing Model, and the fact that the same process should be effective in two such disparate models argues strongly that process reflects a true aspect of animal cognition.

  14. Real-Time River Channel-Bed Monitoring at the Chariton and Mississippi Rivers in Missouri, 2007-09

    Science.gov (United States)

    Rydlund, Jr., Paul H.

    2009-01-01

    Scour and depositional responses to hydrologic events have been important to the scientific community studying sediment transport as well as potential effects on bridges and other hydraulic structures within riverine systems. A river channel-bed monitor composed of a single-beam transducer was installed on a bridge crossing the Chariton River near Prairie Hill, Missouri (structure L-344) as a pilot study to evaluate channel-bed change in response to the hydrologic condition disseminated from an existing streamgage. Initial results at this location led to additional installations in cooperation with the Missouri Department of Transportation at an upstream Chariton River streamgage location at Novinger, Missouri (structure L-534) and a Mississippi River streamgage location near Mehlville, Missouri (structures A-1850 and A-4936). In addition to stage, channel-bed elevation was collected at all locations every 15 minutes and transmitted hourly to a U.S. Geological Survey database. Bed elevation data for the Chariton River location at Novinger and the Mississippi River location near Mehlville were provided to the World Wide Web for real-time monitoring. Channel-bed data from the three locations indicated responses to hydrologic events depicted in the stage record; however, notable bedforms apparent during inter-event flows also may have affected the relation of scour and deposition to known hydrologic events. Throughout data collection periods, Chariton River locations near Prairie Hill and Novinger reflected bed changes as much as 13 feet and 5 feet. Nearly all of the bed changes correlated well with the hydrographic record at these locations. The location at the Mississippi River near Mehlville indicated a much more stable channel bed throughout the data collection period. Despite missing data resulting from damage to one of the river channel-bed monitors from ice accumulation at the upstream nose of the bridge pier early in the record, the record from the downstream

  15. Shackle in time - time in Shackle

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2015-01-01

    GLS Shackle got much and the crucial inspiration from John Maynard Keynes. But that's not all. He took a number of further consequences of Keynes’ thoughts. This implies for example ideal claims to economists - having to deal with both mechanical time and expectational time. In consequence the idea...

  16. Intelligence, Inspection Time, and Decision Time.

    Science.gov (United States)

    Bates, Timothy C.; Eysenck, Hans J.

    1993-01-01

    Relationships among Multidimensional Aptitude Battery scores, inspection time, choice reaction time, and the odd-man procedure were investigated for 63 female and 25 male adults. No significant relationships were found for these mental speed measures and the Eysenck Personality Questionnaire-Revised dimensions of extraversion, neuroticism, and…

  17. Choosing between his time and her time?

    DEFF Research Database (Denmark)

    Deding, Mette; Lausten, Mette

    When adding up market work and non-market work, Danish men and women work about the same number of hours per day. While men do the major share of the market work, women do the major share of the non-market work. In this paper, we investigate the interaction between the different time use activities...... spouses. This is especially the case for market work and housework, while childcare is different. Thus, when considering labour supply the total workload must be taken into account. Furthermore, the interdependence between the spouses’ working hours suggests that bargaining is taking place...... for Danish working couples. The analysis is based on the Danish Time Use Survey from 2001, which contains detailed time use information for both spouses. We analyse the time used by each spouse on market work and non-market work, taking the endogeneity of time regressors into account. Non-market work...

  18. Time crystals: a review

    Science.gov (United States)

    Sacha, Krzysztof; Zakrzewski, Jakub

    2018-01-01

    Time crystals are time-periodic self-organized structures postulated by Frank Wilczek in 2012. While the original concept was strongly criticized, it stimulated at the same time an intensive research leading to propositions and experimental verifications of discrete (or Floquet) time crystals—the structures that appear in the time domain due to spontaneous breaking of discrete time translation symmetry. The struggle to observe discrete time crystals is reviewed here together with propositions that generalize this concept introducing condensed matter like physics in the time domain. We shall also revisit the original Wilczek’s idea and review strategies aimed at spontaneous breaking of continuous time translation symmetry.

  19. Screen time and children

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/patientinstructions/000355.htm Screen time and children To use the sharing features on ... videos is considered unhealthy screen time. Current Screen Time Guidelines Children under age 2 should have no ...

  20. Is Time Predictability Quantifiable?

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2012-01-01

    Computer architects and researchers in the realtime domain start to investigate processors and architectures optimized for real-time systems. Optimized for real-time systems means time predictable, i.e., architectures where it is possible to statically derive a tight bound of the worst......-case execution time. To compare different approaches we would like to quantify time predictability. That means we need to measure time predictability. In this paper we discuss the different approaches for these measurements and conclude that time predictability is practically not quantifiable. We can only...... compare the worst-case execution time bounds of different architectures....

  1. On Time-II: Newton's Time.

    Science.gov (United States)

    Raju, C. K.

    1991-01-01

    A study of time in Newtonian physics is presented. Newton's laws of motion, falsifiability and physical theories, laws of motion and law of gravitation, and Laplace's demon are discussed. Short bibliographic sketches of Laplace and Karl Popper are included. (KR)

  2. Time flies faster under time pressure.

    Science.gov (United States)

    Rattat, Anne-Claire; Matha, Pauline; Cegarra, Julien

    2018-04-01

    We examined the effects of time pressure on duration estimation in a verbal estimation task and a production task. In both temporal tasks, participants had to solve mazes in two conditions of time pressure (with or without), and with three different target durations (30 s, 60 s, and 90 s). In each trial of the verbal estimation task, participants had to estimate in conventional time units (minutes and seconds) the amount of time that had elapsed since they started to solve the maze. In the production task, they had to press a key while solving the maze when they thought that the trial's duration had reached a target value. Results showed that in both tasks, durations were judged longer with time pressure than without it. However, this temporal overestimation under time pressure did not increase with the length of the target duration. These results are discussed within the framework of scalar expectancy theory. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Frontiers of time

    International Nuclear Information System (INIS)

    Wheeler, J.A.

    1979-01-01

    The author discusses the double-slit experiment and the problem of whether one can choose whether the photon shall have come through both of the slits, or only one of them, after it has already transversed the screen. A proper quantum concept of correlation is formalised as it depends on time. It takes the existence of the dynamic entity under study and the concept of time for granted, and does not transcend the concept of time. Time is absolute and universal in Newtonian physics and in special relativity successive times correspond to successive slices through space-time. Many fingured time is discussed in this context. The concepts of transcending time, causal order without causal order, asymmetry in time and the expansion of the universe, memory and the arrow of time, and the gates of time are all considered. (Auth./C.F.)

  4. Talk of time

    Directory of Open Access Journals (Sweden)

    Johann-Albrecht Meylahn

    2015-06-01

    Full Text Available Maybe, before we speak of time, or maybe whilst we are speaking of time, or maybe after we have spoken of time, in the various modes of time’s insistence to exist, one should give time to the talk of time. There are various different modes of time’s insistence to exist, such as quantum physics in conversation with relativity theory where time is constructed as a fourth dimension of space. Or there are the modes of time in history, religion, psychology and philosophy, and each of these modes is composed, and composes its own specific object called time, and a particular subject who understands and interprets time in that particular mode. Yet, before, whilst or after these modes of time’s insistence to exist, one should maybe give time to time’s time. Give time for the various times to articulate themselves in the various modes of existence, thereby creating both a whole plurality of differing subjects, as well as plurality of differing objects, all called ‘time’. Once time has been given time to talk its talk, to articulate itself within the various modes, it will be interrupted by the articulations of time in various modes of time still to come. These disruptions of time by time always still to come opens the door for a theological narrative – a narrative on time, but created by the coming of messianic times, interpreted in the mode of hope but also in the mode of a promise from the past.

  5. Time and Teaching

    Science.gov (United States)

    McEwan, Anna E.

    2012-01-01

    This essay invites reflection on the phenomena of time as it impacts the day-to-day life of teachers. It also explores assumptions about time and teaching in three areas: first, beliefs about the force of time and the teacher's struggle to control it; second, beliefs about the potential of time and the benefits of its passing for teachers and…

  6. Perceptions of Time and Long Time Intervals

    Energy Technology Data Exchange (ETDEWEB)

    Drottz-Sjoeberg, Britt-Marie [Norwegian Univ. of Science and Technology, Trondheim (Norway). Dept. of Psychology

    2006-09-15

    There are certainly many perspectives presented in the literature on time and time perception. This contribution has focused on perceptions of the time frames related to risk and danger of radiation from a planned Swedish repository for spent nuclear fuel. Respondents from two municipalities judged SSI's reviews of the entrepreneur's plans and work of high importance, and more important the closer to our time the estimate was given. Similarly were the consequences of potential leakage from a repository perceived as more serious the closer it would be to our time. Judgements of risks related to the storage of spent nuclear fuel were moderately large on the used measurement scales. Experts are experts because they have more knowledge, and in this context they underlined e.g. the importance of reviews of the radiation situation of time periods up to 100,000 years. It was of interest to note that 55% of the respondents from the municipalities did not believe that the future repository would leak radioactivity. They were much more pessimistic with respect to world politics, i.e. a new world war. However, with respect to the seriousness of the consequences given a leakage from the repository, the public group consistently gave high risk estimates, often significantly higher than those of the expert group. The underestimations of time estimates, as seen in the tasks of pinpointing historic events, provide examples of the difficulty of making estimations involving long times. Similar results showed that thinking of 'the future' most often involved about 30 years. On average, people reported memories of about 2.5 generations back in time, and emotional relationships stretching approximately 2.5 generations into the future; 94% of the responses, with respect to how many future generations one had an emotional relationship, were given in the range of 1-5 generations. Similarly, Svenson and Nilsson found the opinion that the current generations

  7. Perceptions of Time and Long Time Intervals

    International Nuclear Information System (INIS)

    Drottz-Sjoeberg, Britt-Marie

    2006-01-01

    There are certainly many perspectives presented in the literature on time and time perception. This contribution has focused on perceptions of the time frames related to risk and danger of radiation from a planned Swedish repository for spent nuclear fuel. Respondents from two municipalities judged SSI's reviews of the entrepreneur's plans and work of high importance, and more important the closer to our time the estimate was given. Similarly were the consequences of potential leakage from a repository perceived as more serious the closer it would be to our time. Judgements of risks related to the storage of spent nuclear fuel were moderately large on the used measurement scales. Experts are experts because they have more knowledge, and in this context they underlined e.g. the importance of reviews of the radiation situation of time periods up to 100,000 years. It was of interest to note that 55% of the respondents from the municipalities did not believe that the future repository would leak radioactivity. They were much more pessimistic with respect to world politics, i.e. a new world war. However, with respect to the seriousness of the consequences given a leakage from the repository, the public group consistently gave high risk estimates, often significantly higher than those of the expert group. The underestimations of time estimates, as seen in the tasks of pinpointing historic events, provide examples of the difficulty of making estimations involving long times. Similar results showed that thinking of 'the future' most often involved about 30 years. On average, people reported memories of about 2.5 generations back in time, and emotional relationships stretching approximately 2.5 generations into the future; 94% of the responses, with respect to how many future generations one had an emotional relationship, were given in the range of 1-5 generations. Similarly, Svenson and Nilsson found the opinion that the current generations' general responsibility for

  8. Time in quantum mechanics

    CERN Document Server

    Mayato, R; Egusquiza, I

    2002-01-01

    The treatment of time in quantum mechanics is still an important and challenging open question in the foundation of the theory. This book describes the problems, and the attempts and achievements in defining, formalizing and measuring different time quantities in quantum theory, such as the parametric (clock) time, tunneling times, decay times, dwell times, delay times, arrival times or jump times. This multiauthored book, written as an introductory guide for the non-initiated as well as a useful source of information for the expert, covers many of the open questions. A brief historical overview is to be found in the introduction. It is followed by 12 chapters devoted to conceptual and theoretical investigations as well as experimental issues in quantum-mechanical time measurements. This unique monograph should attract physicists as well as philosophers of science working in the foundations of quantum physics.

  9. Cosmology and time

    Directory of Open Access Journals (Sweden)

    Balbi Amedeo

    2013-09-01

    Full Text Available Time has always played a crucial role in cosmology. I review some of the aspects of the present cosmological model which are more directly related to time, such as: the definition of a cosmic time; the existence of typical timescales and epochs in an expanding universe; the problem of the initial singularity and the origin of time; the cosmological arrow of time.

  10. ITC FOR TIME MANAGEMENT

    OpenAIRE

    MARES VALERICA; MARES MARIUS DANIEL

    2014-01-01

    The efficient management of time is essential in any profession and in any activity domain. Anybody can increase his capacity to organize his time and get important benefits from it. The way in which one organizes his time will always have a direct impact on the objects of his work (resources and activities), so that it is worth allocating time for developing some instruments and techniques that could help planning and organizing time efficiently and attaining the objectives while meeting the...

  11. Time and timing in vehicle routing problems

    NARCIS (Netherlands)

    Jabali, O.

    2010-01-01

    The distribution of goods to a set of geographically dispersed customers is a common problem faced by carrier companies, well-known as the Vehicle Routing Problem (VRP). The VRP consists of finding an optimal set of routes that minimizes total travel times for a given number of vehicles with a fixed

  12. A Student’s t Mixture Probability Hypothesis Density Filter for Multi-Target Tracking with Outliers

    Science.gov (United States)

    Liu, Zhuowei; Chen, Shuxin; Wu, Hao; He, Renke; Hao, Lin

    2018-01-01

    In multi-target tracking, the outliers-corrupted process and measurement noises can reduce the performance of the probability hypothesis density (PHD) filter severely. To solve the problem, this paper proposed a novel PHD filter, called Student’s t mixture PHD (STM-PHD) filter. The proposed filter models the heavy-tailed process noise and measurement noise as a Student’s t distribution as well as approximates the multi-target intensity as a mixture of Student’s t components to be propagated in time. Then, a closed PHD recursion is obtained based on Student’s t approximation. Our approach can make full use of the heavy-tailed characteristic of a Student’s t distribution to handle the situations with heavy-tailed process and the measurement noises. The simulation results verify that the proposed filter can overcome the negative effect generated by outliers and maintain a good tracking accuracy in the simultaneous presence of process and measurement outliers. PMID:29617348

  13. The direction of time

    CERN Document Server

    Reichenbach, Hans

    1999-01-01

    Ever a source of philosophical conjecture and debate, the concept of time represents the beating heart of physics. This final work by the distinguished physicist Hans Reichenbach represents the culmination and integration of a lifetime's philosophical contributions and inquiries into the analysis of time. The result is an outstanding overview of such qualitative, or topological, attributes of time as order and direction.Beginning with a discussion of the emotive significance of time, Reichenbach turns to an examination of the time order of mechanics, the time direction of thermodynamics and m

  14. Children, Time, and Play

    DEFF Research Database (Denmark)

    Elkind, David; Rinaldi, Carla; Flemmert Jensen, Anne

    Proceedings from the conference "Children, Time, and Play". Danish University of Education, January 30th 2003.......Proceedings from the conference "Children, Time, and Play". Danish University of Education, January 30th 2003....

  15. Time Discretization Techniques

    KAUST Repository

    Gottlieb, S.; Ketcheson, David I.

    2016-01-01

    The time discretization of hyperbolic partial differential equations is typically the evolution of a system of ordinary differential equations obtained by spatial discretization of the original problem. Methods for this time evolution include

  16. Timing system observations

    International Nuclear Information System (INIS)

    Winans, J.

    1994-01-01

    The purpose of this document is to augment Synchronized Time Stamp Support authored by Jim Kowalkowski. This document provides additional documentation to clarify and explain software involved in timing operations of the accelerator

  17. Quantum tunneling time

    International Nuclear Information System (INIS)

    Wang, Z.S.; Lai, C.H.; Oh, C.H.; Kwek, L.C.

    2004-01-01

    We present a calculation of quantum tunneling time based on the transition duration of wave peak from one side of a barrier to the other. In our formulation, the tunneling time comprises a real and an imaginary part. The real part is an extension of the phase tunneling time with quantum corrections whereas the imaginary time is associated with energy derivatives of the probability amplitudes

  18. Successful time management

    CERN Document Server

    Forsyth, Patrick

    2016-01-01

    Packed with tips and techniques, Successful Time Management serves as a guide to reviewing and assessing new work practices to improve time management. It includes great time-saving ideas, practical solutions, checklists, and advice on controlling paperwork, delegating and working with others, prioritizing to focus on key issues, and getting and staying organized. This new third edition contains new practical tips on using email in a time effective manner and dealing with other internet-based tools and apps to help productivity.

  19. Time management and procrastination

    OpenAIRE

    van Eerde, W.; Mumford, M.D.; Frese, M.

    2015-01-01

    This chapter combines the topics time management and procrastination. Time management is an overarching term derived from popular notions on how to be effective at work. Procrastination has been mainly researched from a personality perspective, addressing the emotional and psychological issues of the phenomenon in more detail. First, I describe time management and procrastination, and next I address interventions that may help people in overcoming procrastination. Studies on time management s...

  20. Measuring Business Cycle Time.

    OpenAIRE

    Stock, James H

    1987-01-01

    The business cycle analysis of Arthur F. Burns and Wesley C. Mitchell and the National Bureau of Economic Research presumed that aggregate economic variables evolve on a time scale defined by business cycle turning points rather than by months or quarters. Do macroeconomic variables appear to evolve on an economic rather than a calendar time scale? Evidence presented here suggests that they do. However, the estimated economic time scales are only weakly related to business cycle time scales, ...

  1. Buying time promotes happiness

    NARCIS (Netherlands)

    Whillans, Ashley; Dunn, Elizabeth; Smeets, Paul M.; Bekkers, R.H.F.P.; Norton, M.I.

    2017-01-01

    Around the world, increases in wealth have produced an unintended consequence: a rising sense of time scarcity. We provide evidence that using money to buy time can provide a buffer against this time famine, thereby promoting happiness. Using large, diverse samples from the United States, Canada,

  2. Pushing for Part Time.

    Science.gov (United States)

    Geber, Beverly

    1987-01-01

    More employees are choosing to work part time. Although this trend started because of working women, some men are choosing part-time positions. Part-time employees forfeit salary and promotion potential, yet most feel the trade is fair and that they are more productive during their working hours. (CH)

  3. Value of travel time.

    Science.gov (United States)

    2016-08-01

    Knowingly or not, people generally place economic value on their time. Wage workers are paid a rate per hour, and service providers may charge per hour of their time. In the transportation realm, travelers place a value on their travel time and have ...

  4. Construction time of PWRs

    International Nuclear Information System (INIS)

    Moreira, João M.L.; Gallinaro, Bruno; Carajilescov, Pedro

    2013-01-01

    The construction time of PWRs is studied considering published data about nuclear power plants in the world. For the 268 PWRs in operation in 2010, the mode of the construction time distribution is around 5–6 years, and 80% of the plants were built in less than 120 months. To circumvent the problem of comparing plants with different size we normalized the construction time to plants with 1 GW. We restricted the analysis to 201 PWRs which suffered less from external factors that were beyond the control of the management from 1965 to 2010. The results showed that the normalized construction time did not increase over the years and nor with the plants’ gross power level. The learning rate of the industry regarding normalized construction times showed a reduction with 95% confidence level of about 0.56±0.07 months for each 10 GW of installed capacity. Over the years the normalized construction time decreased and became more predictable. The data showed that countries with more centralized regulatory, construction and operation environments were able to build PWRs in shorter times. Countries less experienced with the nuclear technology built PWRs in longer times. - Highlights: ► The construction time of PWRs is analyzed based on historical data. ► Different factors affecting construction time are considered in the analyses. ► The normalized construction time of PWRs decreased with time and gross power level. ► Countries with more centralized institutions built PWRs more quickly

  5. Time Management for Educators.

    Science.gov (United States)

    Burden, Paul R.

    Time management principles can help teachers become more aware of ways in which time can be used to the greatest advantage. An exploration of personal time perspectives is a step toward establishing effective patterns of behavior. Productivity may be high in the morning and low in the late afternoon, for example, and organizing some activities to…

  6. 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

  7. Thomas precession in time

    International Nuclear Information System (INIS)

    Strnad, J.

    1983-01-01

    A Thomas precession mechanism is described which would become effective in a symmetric six-dimensional space-time if the time vector of a particle would rotate uniformly. For the effect a discrepancy of the decay time of particles in flight, proportional to their kinetic energy would be characteristic

  8. ITC FOR TIME MANAGEMENT

    Directory of Open Access Journals (Sweden)

    MARES VALERICA

    2014-12-01

    Full Text Available The efficient management of time is essential in any profession and in any activity domain. Anybody can increase his capacity to organize his time and get important benefits from it. The way in which one organizes his time will always have a direct impact on the objects of his work (resources and activities, so that it is worth allocating time for developing some instruments and techniques that could help planning and organizing time efficiently and attaining the objectives while meeting the deadlines.

  9. Time and man

    CERN Document Server

    Elton, L. R. B

    1978-01-01

    Time and Man focuses on the endeavors of humans to probe the mysteries of time and to elucidate its properties. The discussions are both philosophical and factual in nature and encompass science as well as the physical sciences, biology and related disciplines (for example, evolution), and the humanities (for example, religion). Factual information is presented to help the reader gain a better understanding of the concepts associated with time.Comprised of nine chapters, this volume first considers the passage of time and the experiences which humans associate with the concept of time before r

  10. Real Time Revisited

    Science.gov (United States)

    Allen, Phillip G.

    1985-12-01

    The call for abolishing photo reconnaissance in favor of real time is once more being heard. Ten years ago the same cries were being heard with the introduction of the Charge Coupled Device (CCD). The real time system problems that existed then and stopped real time proliferation have not been solved. The lack of an organized program by either DoD or industry has hampered any efforts to solve the problems, and as such, very little has happened in real time in the last ten years. Real time is not a replacement for photo, just as photo is not a replacement for infra-red or radar. Operational real time sensors can be designed only after their role has been defined and improvements made to the weak links in the system. Plodding ahead on a real time reconnaissance suite without benefit of evaluation of utility will allow this same paper to be used ten years from now.

  11. Buying time promotes happiness.

    Science.gov (United States)

    Whillans, Ashley V; Dunn, Elizabeth W; Smeets, Paul; Bekkers, Rene; Norton, Michael I

    2017-08-08

    Around the world, increases in wealth have produced an unintended consequence: a rising sense of time scarcity. We provide evidence that using money to buy time can provide a buffer against this time famine, thereby promoting happiness. Using large, diverse samples from the United States, Canada, Denmark, and The Netherlands ( n = 6,271), we show that individuals who spend money on time-saving services report greater life satisfaction. A field experiment provides causal evidence that working adults report greater happiness after spending money on a time-saving purchase than on a material purchase. Together, these results suggest that using money to buy time can protect people from the detrimental effects of time pressure on life satisfaction.

  12. Simulating detectors dead time

    International Nuclear Information System (INIS)

    Rustom, Ibrahim Farog Ibrahim

    2015-06-01

    Nuclear detectors are used in all aspects of nuclear measurements. All nuclear detectors are characterized by their dead time i.e. the time needed by a detector to recover from a previous incident. A detector dead time influences measurements taken by a detector and specially when measuring high decay rate (>) where is the detector dead time. Two models are usually used to correct for the dead time effect: the paralayzable and the non-paralayzable models. In the current work we use Monte Carlo simulation techniques to simulate radioactivity and the effect of dead time and the count rate of a detector with a dead time =5x10 - 5s assuming the non-paralayzable model. The simulation indicates that assuming a non -paralayzable model could be used to correct for decay rate measured by a detector. The reliability of the non-paralayzable model to correct the measured decay rate could be gauged using the Monte Carlo simulation. (Author)

  13. Where Times Meet

    Directory of Open Access Journals (Sweden)

    Theodore R. Schatzki

    2005-01-01

    Full Text Available This essay pursues two goals: (1 to argue that two fundamental types of time—the time of objective reality and “the time of the soul”—meet in human activity and history and (2 to defend the legitimacy of calling a particular version of the second type a kind of time. The essay begins by criticizing Paul Ricoeur’s version of the claim that times of these two sorts meet in history. It then presents an account of human activity based on Heidegger’s Being and Time, according to which certain times of the two types—existential temporality and succession—meet in human activity. The legitimacy of calling existential temporality a kind of time is then defended via an expanded analysis of activity that examines where the two times meet there. The concluding section briefly considers a conception of historical time due to David Carr before showing why history is a broader domain encompassing human activity where the two times meet.

  14. On Time Performance Pressure

    Science.gov (United States)

    Connell, Linda; Wichner, David; Jakey, Abegael

    2013-01-01

    Within many operations, the pressures for on-time performance are high. Each month, on-time statistics are reported to the Department of Transportation and made public. There is a natural tendency for employees under pressure to do their best to meet these objectives. As a result, pressure to get the job done within the allotted time may cause personnel to deviate from procedures and policies. Additionally, inadequate or unavailable resources may drive employees to work around standard processes that are seen as barriers. However, bypassing practices to enable on-time performance may affect more than the statistics. ASRS reports often highlight on-time performance pressures which may result in impact across all workgroups in an attempt to achieve on-time performance. Reporters often provide in-depth insights into their experiences which can be used by industry to identify and focus on the implementation of systemic fixes.

  15. Peircean diagrams of time

    DEFF Research Database (Denmark)

    Øhrstrøm, Peter

    2011-01-01

    Some very good arguments can be given in favor of the Augustinean wisdom, according to which it is impossible to provide a satisfactory definition of the concept of time. However, even in the absence of a proper definition, it is possible to deal with conceptual problems regarding time. It can...... be done in terms of analogies and metaphors. In particular, it is attractive to make use of Peirce's diagrams by means of which various kinds of conceptual experimentation can be carried out. This paper investigates how Peircean diagrams can be used within the study of time. In particular, we discuss 1......) the topological properties of time, 2) the implicative structure in tense logic, 3) the notions of open future and branching time models, and finally 4) tenselogical alternatives to branching time models....

  16. When time matters.

    Science.gov (United States)

    Theadore, Jason C

    2011-01-01

    The most important organizational resource is energy. The most important resource in time management is energy. Managing energy, not time, can help create encouraging time management skills and appropriate work life balance. Once a leader understands that time should be spent on things that are important instead of everything that is urgent, you can begin to develop a balance that will support your values, your family, and your organization. When leaders find meaningful ways to add a sense of purpose to their work they can personally improve themselves and their organizations. If your personal values do not align with the values of your organization you will never work with a true sense of purpose. Make the time to manage your energy. You will be surprised how much free time you find.

  17. Intrinsic Time Quantum Geometrodynamics

    OpenAIRE

    Ita III, Eyo Eyo; Soo, Chopin; Yu, Hoi-Lai

    2015-01-01

    Quantum Geometrodynamics with intrinsic time development and momentric variables is presented. An underlying SU(3) group structure at each spatial point regulates the theory. The intrinsic time behavior of the theory is analyzed, together with its ground state and primordial quantum fluctuations. Cotton-York potential dominates at early times when the universe was small; the ground state naturally resolves Penrose's Weyl Curvature Hypothesis, and thermodynamic and gravitational `arrows of tim...

  18. Time functions revisited

    Science.gov (United States)

    Fathi, Albert

    2015-07-01

    In this paper we revisit our joint work with Antonio Siconolfi on time functions. We will give a brief introduction to the subject. We will then show how to construct a Lipschitz time function in a simplified setting. We will end with a new result showing that the Aubry set is not an artifact of our proof of existence of time functions for stably causal manifolds.

  19. Time Dependent Quantum Mechanics

    OpenAIRE

    Morrison, Peter G.

    2012-01-01

    We present a systematic method for dealing with time dependent quantum dynamics, based on the quantum brachistochrone and matrix mechanics. We derive the explicit time dependence of the Hamiltonian operator for a number of constrained finite systems from this formalism. Once this has been achieved we go on to calculate the wavevector as a function of time, in order to demonstrate the use of matrix methods with respect to several concrete examples. Interesting results are derived for elliptic ...

  20. Wait times in Canada.

    Science.gov (United States)

    MacKinnon, Janice Christine

    2017-07-01

    A significant barrier to accessing healthcare in Canada is long waiting lists, which can be linked to the way that Medicare was structured. After significant pressure, provincial governments began to address wait times. An example of a successful strategy to reduce wait times for elective surgery is the Saskatchewan Surgical Initiative, which saw wait times in the province change from being among the longest in Canada to the shortest.

  1. TIME MANAGEMENT FOR ACCOUNTANTS

    Directory of Open Access Journals (Sweden)

    Cristina Elena BIGIOI

    2016-06-01

    Full Text Available Time is money. Every accountant knows that. In our country, the taxes are changing frequently. The accountants have to update their fiscal knowledge. The purpose of the article is to find how the accountants manage their time, taking into consideration the number of fiscal declarations and the fiscal changes. In this article we present some ways to improve time management for accountants.

  2. The TRISTAN timing system

    International Nuclear Information System (INIS)

    Urakawa, Junji; Ishii, Kazuhiro; Kadokura, Eiichi; Kawamoto, Takashi; Kikuchi, Mitsuo; Kikutani, Eiji

    1990-01-01

    The TRISTAN accelerator complex comprises four accelerators: a 200 MeV electron linac for positron production, a 2.5 GeV linac, an 8 GeV accumulation ring (AR) and a 30 GeV main ring (MR). The TRISTAN timing system is divided into fast and slow timing systems. The fast timing system supplies timing signals (fast timing) for devices whose operation is synchronized with bunched beams from either the linac or the AR. These signals are also used in various beam monitors and beam feedback systems. The slow timing system generates trigger signals (slow timing) in order to achieve synchronization between the magnetic field and the rf accelerating voltage of the AR or MR. These triggers are also used for the automatic operation of machines. The TRISTAN timing system fulfills the following features with the required flexibility and extensibility while in the operation mode: (1) the linac gun trigger signals and the AR revolution clock are synchronized within ≅ 100 ps in timing accuracy, and a short pulse (≅ 1.5 ns) from the linac is injected and accumulated into an arbitrarily selected bucket of AR for a long time; (2) bucket matching between the AR and MR is achieved within ±6 ps in timing accuracy and a single bunched beam from the AR is injected into an arbitrarily selected bucket of the MR; (3) the slow timing system manages the operation mode of the AR and MR with both flexibility and extensibility; (4) the synchronization signals are transmitted through coaxial cables over a circumference of 3 km from the main control room. (orig.)

  3. Time-varying BRDFs.

    Science.gov (United States)

    Sun, Bo; Sunkavalli, Kalyan; Ramamoorthi, Ravi; Belhumeur, Peter N; Nayar, Shree K

    2007-01-01

    The properties of virtually all real-world materials change with time, causing their bidirectional reflectance distribution functions (BRDFs) to be time varying. However, none of the existing BRDF models and databases take time variation into consideration; they represent the appearance of a material at a single time instance. In this paper, we address the acquisition, analysis, modeling, and rendering of a wide range of time-varying BRDFs (TVBRDFs). We have developed an acquisition system that is capable of sampling a material's BRDF at multiple time instances, with each time sample acquired within 36 sec. We have used this acquisition system to measure the BRDFs of a wide range of time-varying phenomena, which include the drying of various types of paints (watercolor, spray, and oil), the drying of wet rough surfaces (cement, plaster, and fabrics), the accumulation of dusts (household and joint compound) on surfaces, and the melting of materials (chocolate). Analytic BRDF functions are fit to these measurements and the model parameters' variations with time are analyzed. Each category exhibits interesting and sometimes nonintuitive parameter trends. These parameter trends are then used to develop analytic TVBRDF models. The analytic TVBRDF models enable us to apply effects such as paint drying and dust accumulation to arbitrary surfaces and novel materials.

  4. eTime

    OpenAIRE

    Singh J P

    2000-01-01

    The paper examines various measures of time and argues that none of the measures meet the needs of commerce and law for transactions carried out in the cyberspace. It therefore suggests that a new measure of the time and epoch, called eTime be introduced. The paper further suggests that the assumed zero of eTime should be the epoch of signing ‘A Declaration of Independence of Cyberspace’, i.e. Fri, Feb 9, 1996 17:16:35 +0100 at Davos, Switzerland.

  5. Time Functions as Utilities

    Science.gov (United States)

    Minguzzi, E.

    2010-09-01

    Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have an analog in the field of microeconomics known as utility theory. In a chronological spacetime the semi-time functions correspond to the utilities for the chronological relation, while in a K-causal (stably causal) spacetime the time functions correspond to the utilities for the K + relation (Seifert’s relation). By exploiting this analogy, we are able to import some mathematical results, most notably Peleg’s and Levin’s theorems, to the spacetime framework. As a consequence, we prove that a K-causal (i.e. stably causal) spacetime admits a time function and that the time or temporal functions can be used to recover the K + (or Seifert) relation which indeed turns out to be the intersection of the time or temporal orderings. This result tells us in which circumstances it is possible to recover the chronological or causal relation starting from the set of time or temporal functions allowed by the spacetime. Moreover, it is proved that a chronological spacetime in which the closure of the causal relation is transitive (for instance a reflective spacetime) admits a semi-time function. Along the way a new proof avoiding smoothing techniques is given that the existence of a time function implies stable causality, and a new short proof of the equivalence between K-causality and stable causality is given which takes advantage of Levin’s theorem and smoothing techniques.

  6. Time Here, Time There, Time Everywhere: Teaching Young Children Time through Daily Routine

    Science.gov (United States)

    Lee, Joohi; Lee, Joo Ok; Fox, Jill

    2009-01-01

    According to Piaget, 5- or 6-year-old children gradually acquire the concept of time based on events (Piaget, 1969). In his experiment of investigating children's time concepts, Piaget found that children of these ages were able to place pictures based on sequential events with some errors; the younger children made more errors. The National…

  7. Validating Timed Component Contracts

    DEFF Research Database (Denmark)

    Le Guilly, Thibaut; Liu, Shaoying; Olsen, Petur

    2015-01-01

    This paper presents a technique for testing software components with contracts that specify functional behavior, synchronization, as well as timing behavior. The approach combines elements from unit testing with model-based testing techniques for timed automata. The technique is implemented...... in an online testing tool, and we demonstrate its use on a concrete use case....

  8. 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.

  9. Shackle in Time

    DEFF Research Database (Denmark)

    Madsen, Mogens Ove

    2016-01-01

    GLS Shackle got much and the crucial inspiration from John Maynard Keynes. But that’s not all. He took a number of further consequences of Keynes’ thoughts. This implies for example ideal claims to economists — having to deal with both mechanical time and expectational time. In consequence the idea...

  10. Time Will Tell

    DEFF Research Database (Denmark)

    Dalsgård, Anne Line

    2017-01-01

    in the neighbourhood, as credit credit cards are locked in a punctuated time, where dates are crucial. Using an episode that I happened to be part of as point of departure, I argue that decepção is the estrangement experienced, when a moment of trust is thrown back upon you, distorted by the process of time....

  11. The metrology of time.

    Science.gov (United States)

    Arias, Elisa Felicitas

    2005-09-15

    Measuring time is a continuous activity, an international and restless enterprise hidden in time laboratories spread all over the planet. The Bureau International des Poids et Mesures is charged with coordinating activities for international timekeeping and it makes use of the world's capacity to produce a remarkably stable and accurate reference time-scale. Commercial atomic clocks beating the second in national laboratories can reach a stability of one part in 10(14) over a 5 day averaging time, compelling us to research the most highly performing methods of remote clock comparison. The unit of the international time-scale is the second of the International System of Units, realized with an uncertainty of the order 10(-15) by caesium fountains. Physicists in a few time laboratories are making efforts to gain one order of magnitude in the uncertainty of the realization of the second, and more refined techniques of time and frequency transfer are in development to accompany this progress. Femtosecond comb technology will most probably contribute in the near future to enhance the definition of the second with the incorporation of optical clocks. We will explain the evolution of the measuring of time, current state-of-the-art measures and future challenges.

  12. Real Time Systems

    DEFF Research Database (Denmark)

    Christensen, Knud Smed

    2000-01-01

    Describes fundamentals of parallel programming and a kernel for that. Describes methods for modelling and checking parallel problems. Real time problems.......Describes fundamentals of parallel programming and a kernel for that. Describes methods for modelling and checking parallel problems. Real time problems....

  13. Time and Teaching

    Science.gov (United States)

    Zielinski, Theresa Julia; Brooks, David W.; Crippen, Kent J.; March, Joe L.

    2001-06-01

    Time management is an important issue for teachers and students. This article discusses teachers' use of time from the perspective of curriculum and instruction. Average high school students spend fewer than 5 hours per week in outside-of-class study; average college students spend about 20 hours. Procrastination, often viewed in a negative light by teachers, usually pays off so well for college students that seniors become better at it than freshmen. Three suggestions for designing instruction are: test early and often; do not waste the best students' time in an effort to improve overall performance; and use engaging activities that motivate students to give of their time. The impact of computers on curricula is a double-edged sword. Time must be devoted to teaching the use of applications, but the programs reduce busywork. Will this turn out to be a simple tradeoff, or will the programs make us much more efficient so that less time is required? Will computer programs ultimately lead to an expanded criterion for expertise, thus demanding even more time to become an expert? These issues are described and suggestions for controlling time during instruction are provided.

  14. Time management and procrastination

    NARCIS (Netherlands)

    van Eerde, W.; Mumford, M.D.; Frese, M.

    2015-01-01

    This chapter combines the topics time management and procrastination. Time management is an overarching term derived from popular notions on how to be effective at work. Procrastination has been mainly researched from a personality perspective, addressing the emotional and psychological issues of

  15. Time-interpolator

    International Nuclear Information System (INIS)

    Blok, M. de; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

    1990-01-01

    This report describes a time-interpolator with which time differences can be measured using digital and analog techniques. It concerns a maximum measuring time of 6.4 μs with a resolution of 100 ps. Use is made of Emitter Coupled Logic (ECL) and analogues of high-frequency techniques. The difficulty which accompanies the use of ECL-logic is keeping as short as possible the mutual connections and closing properly the outputs in order to avoid reflections. The digital part of the time-interpolator consists of a continuous running clock and logic which converts an input signal into a start- and stop signal. The analog part consists of a Time to Amplitude Converter (TAC) and an analog to digital converter. (author). 3 refs.; 30 figs

  16. Leisure Time Invention

    DEFF Research Database (Denmark)

    Davis, Lee N.; Davis, Jerome D.; Hoisl, Karin

    2013-01-01

    the employee is away from the workplace. We build on existing theory in the fields of organizational creativity and knowledge recombination, especially work relating context to creativity. The paper’s main theoretical contribution is to extend our understanding of the boundaries of employee creativity......This paper studies the contextual factors that influence whether invention occurs during work time or leisure time. Leisure time invention, a potentially important but thus far largely unexplored source of employee creativity, refers to invention where the main underlying idea occurs while...... by adding to the discussion of how access to and exploitation of different types of resources—during work hours or during leisure time — may affect creativity. Based on survey data from more than 3,000 inventions from German employee inventors, we find that leisure time inventions are more frequently...

  17. Fast timing discriminator

    International Nuclear Information System (INIS)

    Lo, C.C.

    1977-01-01

    The processing of pulses with very fast risetimes for timing purposes involves many problems because of the large equivalent bandwidths involved. For pulses with risetimes in the 150 ps range (and full widths at half maximum (FWHM) of 400 ps) bandwidths in excess of 1GHz are required. Furthermore, these very narrow pulses with current amplitudes as small as 1 mA carry very small charges ( -12 coulomb), therefore, requiring very sensitive trigger circuits. The difficulty increases when timing characteristics in the picosecond range are sought especially when a wide input signal amplitude range causes a time-walk problem. The fast timing discriminator described has a time-walk of approximately +-75 ps over the input signal range from 80 mV to 3V. A schematic of the discriminator is included, and operation and performance are discussed

  18. Time, money, and morality.

    Science.gov (United States)

    Gino, Francesca; Mogilner, Cassie

    2014-02-01

    Money, a resource that absorbs much daily attention, seems to be involved in much unethical behavior, which suggests that money itself may corrupt. This research examined a way to offset such potentially deleterious effects-by focusing on time, a resource that tends to receive less attention than money but is equally ubiquitous in daily life. Across four experiments, we examined whether shifting focus onto time can salvage individuals' ethicality. We found that implicitly activating the construct of time, rather than money, leads individuals to behave more ethically by cheating less. We further found that priming time reduces cheating by making people reflect on who they are. Implications for the use of time primes in discouraging dishonesty are discussed.

  19. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos

    2013-01-01

    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  20. Forbidden time travel

    DEFF Research Database (Denmark)

    Nøjgaard, Nikolai; Geiß, Manuela; Merkle, Daniel

    2017-01-01

    tree T with a species trees S, relative to the reconciliation problem without prior knowledge of the event types. It is well-known that optimal reconciliations in the unlabeled case may violate time-consistency and thus are not biologically feasible. Here we investigate the mathematical structure...... of the event labeled reconciliation problem with horizontal transfer. Results: We investigate the issue of time-consistency for the event-labeled version of the reconciliation problem, provide a convenient axiomatic framework, and derive a complete characterization of time-consistent reconciliations....... This characterization depends on certain weak conditions on the event-labeled gene trees that reflect conditions under which evolutionary events are observable at least in principle. We give an O(|V (T)| log(|V (S)|))-time algorithm to decide whether a time-consistent reconciliation map exists. It does not require...

  1. Time in Quantum Mechanics

    International Nuclear Information System (INIS)

    Reznik, B.

    1999-01-01

    Time plays an unusual role in quantum theory, and the measurement of time is very different from the measurement of other physical qualities associated with a particle. As an example, the measurability of when something occurred is conceptually fraught with difficulties within the theory. Time must be measured by clocks, and one must somehow cause the occurrence of the event of interest to interact with a clock to record when that event occurred. But that interaction carries with it an inevitable perturbation of the event itself. I will argue that in addition to the usual ΔtΔE > ℎ associated with the accuracy of any clock, there is an additional ΔtE > ℎ uncertainty in the measurement of the time of arrival of a particle. Furthermore this constraint arises because the timing device can itself prevent the event from ever occurring at all. I will compare time measurements involving physical clocks, with attempts to construct a time operator and describe new difficulties associated with the latter approach

  2. Real time expert systems

    International Nuclear Information System (INIS)

    Asami, Tohru; Hashimoto, Kazuo; Yamamoto, Seiichi

    1992-01-01

    Recently, aiming at the application to the plant control for nuclear reactors and traffic and communication control, the research and the practical use of the expert system suitable to real time processing have become conspicuous. In this report, the condition for the required function to control the object that dynamically changes within a limited time is presented, and the technical difference between the real time expert system developed so as to satisfy it and the expert system of conventional type is explained with the actual examples and from theoretical aspect. The expert system of conventional type has the technical base in the problem-solving equipment originating in STRIPS. The real time expert system is applied to the fields accompanied by surveillance and control, to which conventional expert system is hard to be applied. The requirement for the real time expert system, the example of the real time expert system, and as the techniques of realizing real time processing, the realization of interruption processing, dispersion processing, and the mechanism of maintaining the consistency of knowledge are explained. (K.I.)

  3. Time Asymmetric Quantum Mechanics

    Directory of Open Access Journals (Sweden)

    Arno R. Bohm

    2011-09-01

    Full Text Available The meaning of time asymmetry in quantum physics is discussed. On the basis of a mathematical theorem, the Stone-von Neumann theorem, the solutions of the dynamical equations, the Schrödinger equation (1 for states or the Heisenberg equation (6a for observables are given by a unitary group. Dirac kets require the concept of a RHS (rigged Hilbert space of Schwartz functions; for this kind of RHS a mathematical theorem also leads to time symmetric group evolution. Scattering theory suggests to distinguish mathematically between states (defined by a preparation apparatus and observables (defined by a registration apparatus (detector. If one requires that scattering resonances of width Γ and exponentially decaying states of lifetime τ=h/Γ should be the same physical entities (for which there is sufficient evidence one is led to a pair of RHS's of Hardy functions and connected with it, to a semigroup time evolution t_0≤t<∞, with the puzzling result that there is a quantum mechanical beginning of time, just like the big bang time for the universe, when it was a quantum system. The decay of quasi-stable particles is used to illustrate this quantum mechanical time asymmetry. From the analysis of these processes, we show that the properties of rigged Hilbert spaces of Hardy functions are suitable for a formulation of time asymmetry in quantum mechanics.

  4. Construction time of PWRs

    Energy Technology Data Exchange (ETDEWEB)

    Carajilescov, Pedro; Moreira, Joao M.L., E-mail: pedro.carajilescov@ufabc.edu.b, E-mail: joao.moreira@ufabc.edu.b [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Center of Engineering, Modeling and Applied Social Sciences

    2011-07-01

    The cost of electricity generated by nuclear power is greatly affected by the capital cost, which is dependent on the construction time of the plant. This work analyses the construction time of PWRs in several countries with different market structure and licensing experience. Countries which succeeded to establish a more collaborative environment among utilities, constructors, regulators, and energy planners through effective partnerships were able to build PWRs in shorter times. The construction time in Germany, France and Russia was around 80 months and in Japan, about 60 months. The envelope of 95% of the cases includes a range between 50 and 250 months of construction time. The evaluations show that construction time of PWRs has been longer for countries that did not hold the technology to build their own reactors, and depended on contracts with foreign suppliers. The nominal power of the reactors was considered a measure of plant size, technology complexity and standardization. Countries with standardized reactor designs (France, Japan and Russia) were able to build plants in shorter times. (author)

  5. Values in Time Discounting.

    Science.gov (United States)

    Heilmann, Conrad

    2017-10-01

    Controversies about time discounting loom large in decisions about climate change. Prominently, a particularly controversial debate about time discounting in climate change decision-making has been conducted within climate economics, between the authors of Stern et al. (Stern review on the economics of climate change, 2006) and their critics (most prominently Dasgupta in Comments on the Stern review's economics of climate change, 2006; Tol in Energy Environ 17(6):977-981, 2006; Weitzman in J Econ Lit XLV:703-724, 2007; Nordhaus in J Econ Lit XLV:686-702, 2007). The article examines the role of values in this debate. Firstly, it is shown that time discounting is a case in which values are key because it is at heart an ethical problem. Secondly, it is argued that time discounting in climate economics is a case of economists making frequent and routine references to ethical values and indeed conduct ethical debates with each other. Thirdly, it is argued that there is evidence for deep and pervasive entanglement between facts and values in the prevalent methodologies for time discounting. Finally, it is argued that this means that economists have given up the 'value-free ideal' concerning time discounting, and discussed how the current methodology of time discounting in economics can be improved.

  6. Construction time of PWRs

    International Nuclear Information System (INIS)

    Carajilescov, Pedro; Moreira, Joao M.L.

    2011-01-01

    The cost of electricity generated by nuclear power is greatly affected by the capital cost, which is dependent on the construction time of the plant. This work analyses the construction time of PWRs in several countries with different market structure and licensing experience. Countries which succeeded to establish a more collaborative environment among utilities, constructors, regulators, and energy planners through effective partnerships were able to build PWRs in shorter times. The construction time in Germany, France and Russia was around 80 months and in Japan, about 60 months. The envelope of 95% of the cases includes a range between 50 and 250 months of construction time. The evaluations show that construction time of PWRs has been longer for countries that did not hold the technology to build their own reactors, and depended on contracts with foreign suppliers. The nominal power of the reactors was considered a measure of plant size, technology complexity and standardization. Countries with standardized reactor designs (France, Japan and Russia) were able to build plants in shorter times. (author)

  7. Josephson comparator switching time

    Energy Technology Data Exchange (ETDEWEB)

    Herr, Quentin P; Miller, Donald L; Przybysz, John X [Northrop Grumman, Baltimore, MD (United States)

    2006-05-15

    Comparator performance can be characterized in terms of both sensitivity and decision time. Delta-sigma analogue-to-digital converters are tolerant of sensitivity errors but require short decision time due to feedback. We have analysed the Josephson comparator using the numerical solution of the Fokker-Planck equation, which describes the time evolution of the ensemble probability distribution. At balance, the result is essentially independent of temperature in the range 5-20 K. There is a very small probability, 1 x 10{sup -14}, that the decision time will be longer than seven single-flux-quantum pulse widths, defined as Phi{sub 0}/(I{sub c}R{sub n}). For junctions with a critical current density of 4.5 kA, this decision time is only 20 ps. Decision time error probability decreases rapidly with lengthening time interval, at a rate of two orders of magnitude per pulse width. We conclude that Josephson comparator performance is quite favourable for analogue-to-digital converter applications.

  8. Real-time shadows

    CERN Document Server

    Eisemann, Elmar; Assarsson, Ulf; Wimmer, Michael

    2011-01-01

    Important elements of games, movies, and other computer-generated content, shadows are crucial for enhancing realism and providing important visual cues. In recent years, there have been notable improvements in visual quality and speed, making high-quality realistic real-time shadows a reachable goal. Real-Time Shadows is a comprehensive guide to the theory and practice of real-time shadow techniques. It covers a large variety of different effects, including hard, soft, volumetric, and semi-transparent shadows.The book explains the basics as well as many advanced aspects related to the domain

  9. Real-time specifications

    DEFF Research Database (Denmark)

    David, A.; Larsen, K.G.; Legay, A.

    2015-01-01

    A specification theory combines notions of specifications and implementations with a satisfaction relation, a refinement relation, and a set of operators supporting stepwise design. We develop a specification framework for real-time systems using Timed I/O Automata as the specification formalism......, with the semantics expressed in terms of Timed I/O Transition Systems. We provide constructs for refinement, consistency checking, logical and structural composition, and quotient of specifications-all indispensable ingredients of a compositional design methodology. The theory is implemented in the new tool Ecdar...

  10. Evolution of Time Scales

    Science.gov (United States)

    2006-12-01

    as the fundamental unit of time in the International System of Units. It was defined as ( Metrologia , 1968) “the duration of 9 192 631 770 periods of...atomic time equivalent to the second of ET in principle. The Comité Consultatif pour la Définition de la Seconde (CCDS) of the CIPM recommended...with the definition of the second, the unit of time of the Inter- national System of Units” ( Metrologia , 1971). The CCDS (BIPM Com. Cons. Déf. Seconde

  11. Time-dependent embedding

    OpenAIRE

    Inglesfield, J. E.

    2007-01-01

    A method of solving the time-dependent Schr\\"odinger equation is presented, in which a finite region of space is treated explicitly, with the boundary conditions for matching the wave-functions on to the rest of the system replaced by an embedding term added on to the Hamiltonian. This time-dependent embedding term is derived from the Fourier transform of the energy-dependent embedding potential, which embeds the time-independent Schr\\"odinger equation. Results are presented for a one-dimensi...

  12. Identity/Time

    Directory of Open Access Journals (Sweden)

    Nancy J. Knauer

    2013-09-01

    Full Text Available This paper engages the unspoken fourth dimension of intersectionality—time. Using the construction of lesbian, gay, bisexual, and transgender (LGBT identities as an example, it establishes that identity, as it is lived and experienced, is not only multivalent, but also historically contingent. It then raises a number of points regarding the temporal locality of identity—the influence of time on issues of identity and understanding, its implications for legal interventions, social movement building, and paradigms of progressive change. As the title suggests, the paper asks us to consider the frame of identity over time.

  13. The relaxation time approximation

    International Nuclear Information System (INIS)

    Gairola, R.P.; Indu, B.D.

    1991-01-01

    A plausible approximation has been made to estimate the relaxation time from a knowledge of the transition probability of phonons from one state (r vector, q vector) to other state (r' vector, q' vector), as a result of collision. The relaxation time, thus obtained, shows a strong dependence on temperature and weak dependence on the wave vector. In view of this dependence, relaxation time has been expressed in terms of a temperature Taylor's series in the first Brillouin zone. Consequently, a simple model for estimating the thermal conductivity is suggested. the calculations become much easier than the Callaway model. (author). 14 refs

  14. Time in physics

    CERN Document Server

    Stupar, Sandra

    2017-01-01

    One of the most important questions concerning the foundations of physics, especially since the discovery of relativity and quantum theory, is the nature and role of time. In this book we bring together researchers from different areas of physics, mathematics, computer science and philosophy to discuss the role time plays in physics. There have been few books on this topic to date, and two of the key aims of the workshop and this book are to encourage more researchers to explore this area, and to pique students’ interest in the different roles time plays in physics.

  15. Time and frequency applications.

    Science.gov (United States)

    Hellwig, H

    1993-01-01

    An overview is given of the capabilities of atomic clocks and quartz crystal oscillators in terms of available precision of time and frequency signals. The generation, comparison, and dissemination of time and frequency is then discussed. The principal focus is to survey uses of time and frequency in navigation, communication, and science. The examples given include the Global Positioning System, a satellite-based global navigation system, and general and dedicated communication networks, as well as experiments in general relativity and radioastronomy. The number of atomic clocks and crystal oscillators that are in actual use worldwide is estimated.

  16. Priced Timed Automata

    DEFF Research Database (Denmark)

    Behrmann, Gerd; Larsen, Kim Guldstrand; Rasmussen, Jacob Illum

    2004-01-01

    This contribution reports on the considerable effort made recently towards extending and applying well-established timed automata technology to optimal scheduling and planning problems. The effort of the authors in this direction has to a large extent been carried out as part of the European...... projects VHS [22] and AMETIST [17] and are available in the recently released UPPAAL CORA [12], a variant of the real-time verification tool UPPAAL [20,5] specialized for cost-optimal reachability for the extended model of priced timed automata....

  17. Accelerating time to benefit

    DEFF Research Database (Denmark)

    Svejvig, Per; Geraldi, Joana; Grex, Sara

    Despite the ubiquitous pressure for speed, our approaches to accelerate projects remain constrained to the old-fashioned understanding of the project as a vehicle to deliver products and services, not value. This article explores an attempt to accelerate time to benefit. We describe and deconstruct...... of the time. Although all cases valued speed and speed to benefit, and implemented most practices proposed by the methodology, only three of the five projects were more successful in decreasing time to speed. Based on a multi-case study comparison between these five different projects and their respective...

  18. Optimising Lecture Time

    DEFF Research Database (Denmark)

    Holst-Christensen, Bo

    interest in getting a degree, they prefer the educators to do the work for them. The focus of my experiments have therefore been to develop teaching techniques that ensures that the students study efficiently and at the same time moves the task of identifying which parts of the subjects that are giving...... the students problems from the educator to the students. By using techniques that put more weight on student participation, cooperation and preparation, I have been able to cut significantly down on the time used for lecturing, allowing more time for student work and reflection. As an example by getting...... the students to identify the parts of the subjects that need further explanation, I get the students to take ownership of the learning task and at the same time give me a more direct feedback. By creating teaching materials and exercises that can be used in a number of different ways, it is possible to involve...

  19. Classical time machine

    International Nuclear Information System (INIS)

    Kapuscik, E.

    1992-02-01

    Generalizing concepts of the Einstein radiolocation method and, as a consequence, special relativity transformation rules we get that the time flow in the moving system depends on the direction of motion. 3 refs. (author)

  20. Analysing Stable Time Series

    National Research Council Canada - National Science Library

    Adler, Robert

    1997-01-01

    We describe how to take a stable, ARMA, time series through the various stages of model identification, parameter estimation, and diagnostic checking, and accompany the discussion with a goodly number...

  1. Drug Retention Times

    Energy Technology Data Exchange (ETDEWEB)

    Center for Human Reliability Studies

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user.

  2. How emotions change time

    Directory of Open Access Journals (Sweden)

    Annett eSchirmer

    2011-10-01

    Full Text Available Experimental evidence suggests that emotions can both speed-up and slow-down the internal clock. Speeding-up has been observed for to-be-timed emotional stimuli that have the capacity to sustain attention, whereas slowing-down has been observed for to-be-timed neutral stimuli that are presented in the context of emotional distractors. These effects have been explained by mechanisms that involve changes in bodily arousal, attention or sentience. A review of these mechanisms suggests both merits and difficulties in the explanation of the emotion-timing link. Therefore, a hybrid mechanism involving stimulus-specific sentient representations is proposed as a candidate for mediating emotional influences on time. According to this proposal, emotional events enhance sentient representations, which in turn support temporal estimates. Emotional stimuli with a larger share in ones sentience are then perceived as longer than neutral stimuli with a smaller share.

  3. Finding Time for Fitness

    Science.gov (United States)

    ... with friends. Get social. Try a dance club, hiking group or golf league. Encouragement from others can ... quickly alternating activity produces many of the same benefits of continuous moderate-intensity exercise in less time. ...

  4. Multivariate Time Series Search

    Data.gov (United States)

    National Aeronautics and Space Administration — Multivariate Time-Series (MTS) are ubiquitous, and are generated in areas as disparate as sensor recordings in aerospace systems, music and video streams, medical...

  5. A Dialogue on Time

    DEFF Research Database (Denmark)

    Kofod, Julie Lundbak

    This master thesis examines the distinction between tense logic and first order logic concerning time. In particular it studies whether this distinction exists in physics or not. Firstly a general test is made: translating sentences concern- ing time from physics into the two logics. The results...... here are inconclusive, as it is possible for both logics to represent the sen- tences, so this experiment does not reveal a similar distinction in physics. However this test also reveals some properties of the logics: tense logic holds a local view on time while first order logic holds a global view...... logic and reversibility in physics and tense logic and irreversibility in physics. Through this study it is concluded that it is not possible to see this correspondence with the tested property; time symmetry, since symmetry seems to concern the underlying structures, not the logic itself. It is...

  6. Accelerator-timing system

    International Nuclear Information System (INIS)

    Timmer, E.; Heine, E.

    1985-01-01

    Along the NIKHEF accelerator in Amsterdam (Netherlands), at several places a signal is needed for the sychronisation of all devices with the acceleration process. In this report, basic principles and arrangements of this timing system are described

  7. ALICE Time Projection Chamber

    CERN Multimedia

    Lippmann, C

    2013-01-01

    The Time Projection Chamber (TPC) is the main device in the ALICE 'central barrel' for the tracking and identification (PID) of charged particles. It has to cope with unprecedented densities of charges particles.

  8. Time versus money.

    Science.gov (United States)

    Monga, Ashwani; Zor, Ozum

    2018-04-21

    Consumers are known to spend both time and money. These two resources are often seen as economically comparable because the value of one's time can be equated to a monetary amount, such as one's wage rate. Recent research suggests that even when time and money are economically equivalent, they are psychologically different. We discuss how time (versus money) leads to decision making that is more heuristic rather than systematic, to an orientation that is more emotional rather than value-maximizing, to a thinking process that is more holistic rather than analytic, and to a mindset that is more abstract rather than concrete. Implications arise for a variety of domains such as consumer search, happiness, product evaluation, and charitable giving. Copyright © 2018 Elsevier Ltd. All rights reserved.

  9. Time-predictable architectures

    CERN Document Server

    Rochange, Christine; Uhrig , Sascha

    2014-01-01

    Building computers that can be used to design embedded real-time systems is the subject of this title. Real-time embedded software requires increasingly higher performances. The authors therefore consider processors that implement advanced mechanisms such as pipelining, out-of-order execution, branch prediction, cache memories, multi-threading, multicorearchitectures, etc. The authors of this book investigate the timepredictability of such schemes.

  10. LEADERSHIP AND TIME MANAGEMENT

    OpenAIRE

    NIKEZIC Srdan; BATAVELJIC Dragan; NIKEZIC Stefan; BATAVELJIC Branka

    2014-01-01

    When it comes to resources, it is primarily referred to material and financial and rarely human. It is assumed that human resources are used in the right way that their involvement, measured in time and intensity, is properly set to goals and tasks. Practice, unfortunately disproves this assumption. Employees spend too much time for unnecessary and low-priority activities, not realizing that the implementation of certain, key activities the requirement for achieving the ...

  11. Timing system for PLS

    International Nuclear Information System (INIS)

    Chang, S.S.; Kim, M.S.; Won, S.C.; Choi, S.J.

    1991-01-01

    The PLS timing system consists of a master oscillator, a repetition rate pulse generator, a storage ring rf synchronizing system, and a rf driver and kicker trigger system composed of a fixed delay module and variable delay modules. All the timing modules are installed in the VME crates and controlled by the 32 bit microprocessors, and communicating with the Host computer via Ethernet. This paper describes the architectural design of this system as well as the requirements of performance

  12. Long time series

    DEFF Research Database (Denmark)

    Hisdal, H.; Holmqvist, E.; Hyvärinen, V.

    Awareness that emission of greenhouse gases will raise the global temperature and change the climate has led to studies trying to identify such changes in long-term climate and hydrologic time series. This report, written by the......Awareness that emission of greenhouse gases will raise the global temperature and change the climate has led to studies trying to identify such changes in long-term climate and hydrologic time series. This report, written by the...

  13. Time management a prokrastinace

    OpenAIRE

    Šarmandžijeva, Cagan

    2017-01-01

    The theoretical part of this thesis is focused on time management, its history and importance of the goals and tools, which allow us to organize our time. It will also focus on the issue of procrastination, its origin and occurrence in the history, definition of analysis paralysis and people's attitude towards motivation and self-confrontation. It will also introduce us to several tools used in fight against procrastination. The methodological and practical parts will elaborate on a qualitati...

  14. Hygiene habits through time

    OpenAIRE

    Kalan, Petra

    2013-01-01

    In this work I did a research about hygiene habits of people and their home environment. The work presents how the hygiene habits changed in people home environment through time. The work presents changes of the body hygiene standards adopted by people from the middle ages onward. Todays customs are quite different from the ones we had some time ago. Moreover, hygiene of living environment has also changes which resulted into lower death rate and death illness related to bad hygiene among pop...

  15. BIPM Time Activities Update

    Science.gov (United States)

    2009-11-01

    VNIIFTRI and the PTB [7]. GPS time transfer represents today about 85% of the time links for TAI; in this technique, we make use of different types...campaign visited the PTB, the VNIIFTRI , and the AOS [8]. Already in 1996, the use of GLONASS in standard CGGTTS Common-View mode was proposed, but...are compared on regular basis to GPS and TWSTFT methods [16]. Also, with the agreement of the CCTF (2009), the link between the PTB and VNIIFTRI

  16. Spectral Eclipse Timing

    Science.gov (United States)

    Dobbs-Dixon, Ian; Agol, Eric; Deming, Drake

    2015-12-01

    We utilize multi-dimensional simulations of varying equatorial jet strength to predict wavelength-dependent variations in the eclipse times of gas-giant planets. A displaced hot spot introduces an asymmetry in the secondary eclipse light curve that manifests itself as a measured offset in the timing of the center of eclipse. A multi-wavelength observation of secondary eclipse, one probing the timing of barycentric eclipse at short wavelengths and another probing at longer wavelengths, will reveal the longitudinal displacement of the hot spot and break the degeneracy between this effect and that associated with the asymmetry due to an eccentric orbit. The effect of time offsets was first explored in the IRAC wavebands by Williams et al. Here we improve upon their methodology, extend to a broad range of wavelengths, and demonstrate our technique on a series of multi-dimensional radiative-hydrodynamical simulations of HD 209458b with varying equatorial jet strength and hot-spot displacement. Simulations with the largest hot-spot displacement result in timing offsets of up to 100 s in the infrared. Though we utilize a particular radiative hydrodynamical model to demonstrate this effect, the technique is model independent. This technique should allow a much larger survey of hot-spot displacements with the James Webb Space Telescope than currently accessible with time-intensive phase curves, hopefully shedding light on the physical mechanisms associated with thermal energy advection in irradiated gas giants.

  17. SPECTRAL ECLIPSE TIMING

    International Nuclear Information System (INIS)

    Dobbs-Dixon, Ian; Agol, Eric; Deming, Drake

    2015-01-01

    We utilize multi-dimensional simulations of varying equatorial jet strength to predict wavelength-dependent variations in the eclipse times of gas-giant planets. A displaced hot spot introduces an asymmetry in the secondary eclipse light curve that manifests itself as a measured offset in the timing of the center of eclipse. A multi-wavelength observation of secondary eclipse, one probing the timing of barycentric eclipse at short wavelengths and another probing at longer wavelengths, will reveal the longitudinal displacement of the hot spot and break the degeneracy between this effect and that associated with the asymmetry due to an eccentric orbit. The effect of time offsets was first explored in the IRAC wavebands by Williams et al. Here we improve upon their methodology, extend to a broad range of wavelengths, and demonstrate our technique on a series of multi-dimensional radiative-hydrodynamical simulations of HD 209458b with varying equatorial jet strength and hot-spot displacement. Simulations with the largest hot-spot displacement result in timing offsets of up to 100 s in the infrared. Though we utilize a particular radiative hydrodynamical model to demonstrate this effect, the technique is model independent. This technique should allow a much larger survey of hot-spot displacements with the James Webb Space Telescope than currently accessible with time-intensive phase curves, hopefully shedding light on the physical mechanisms associated with thermal energy advection in irradiated gas giants

  18. SPECTRAL ECLIPSE TIMING

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs-Dixon, Ian [Department of Physics, NYU Abu Dhabi P.O. Box 129188 Abu Dhabi (United Arab Emirates); Agol, Eric [Department of Astronomy, University of Washington, Seattle WA 98195 (United States); Deming, Drake [NASA Astrobiology Institute Virtual Planet Laboratory (United States)

    2015-12-10

    We utilize multi-dimensional simulations of varying equatorial jet strength to predict wavelength-dependent variations in the eclipse times of gas-giant planets. A displaced hot spot introduces an asymmetry in the secondary eclipse light curve that manifests itself as a measured offset in the timing of the center of eclipse. A multi-wavelength observation of secondary eclipse, one probing the timing of barycentric eclipse at short wavelengths and another probing at longer wavelengths, will reveal the longitudinal displacement of the hot spot and break the degeneracy between this effect and that associated with the asymmetry due to an eccentric orbit. The effect of time offsets was first explored in the IRAC wavebands by Williams et al. Here we improve upon their methodology, extend to a broad range of wavelengths, and demonstrate our technique on a series of multi-dimensional radiative-hydrodynamical simulations of HD 209458b with varying equatorial jet strength and hot-spot displacement. Simulations with the largest hot-spot displacement result in timing offsets of up to 100 s in the infrared. Though we utilize a particular radiative hydrodynamical model to demonstrate this effect, the technique is model independent. This technique should allow a much larger survey of hot-spot displacements with the James Webb Space Telescope than currently accessible with time-intensive phase curves, hopefully shedding light on the physical mechanisms associated with thermal energy advection in irradiated gas giants.

  19. Time-resolved studies

    International Nuclear Information System (INIS)

    Mills, D.M.

    1992-01-01

    When new or more powerful probes become available that offer both shorter data-collection times and the opportunity to apply innovative approaches to established techniques, it is natural that investigators consider the feasibility of exploring the kinetics of time-evolving systems. This stimulating area of research not only can lead to insights into the metastable or excited states that a system may populate on its way to a ground state, but can also lead to a better understanding of that final state. Synchrotron radiation, with its unique properties, offers just such a tool to extend X-ray measurements from the static to the time-resolved regime. The most straight-forward application of synchrotron radiation to the study of transient phenomena is directly through the possibility of decreased data-collection times via the enormous increase in flux over that of a laboratory X-ray system. Even further increases in intensity can be obtained through the use of novel X-ray optical devices. Widebandpass monochromators, e.g., that utilize the continuous spectral distribution of synchrotron radiation, can increase flux on the sample several orders of magnitude over conventional X-ray optical systems thereby allowing a further shortening of the data-collection time. Another approach that uses the continuous spectral nature of synchrotron radiation to decrease data-collection times is the open-quote parallel data collectionclose quotes method. Using this technique, intensities as a function of X-ray energy are recorded simultaneously for all energies rather than sequentially recording data at each energy, allowing for a dramatic decrease in the data-collection time

  20. Time to audit.

    Science.gov (United States)

    Smyth, L G; Martin, Z; Hall, B; Collins, D; Mealy, K

    2012-09-01

    Public and political pressures are increasing on doctors and in particular surgeons to demonstrate competence assurance. While surgical audit is an integral part of surgical practice, its implementation and delivery at a national level in Ireland is poorly developed. Limits to successful audit systems relate to lack of funding and administrative support. In Wexford General Hospital, we have a comprehensive audit system which is based on the Lothian Surgical Audit system. We wished to analyse the amount of time required by the Consultant, NCHDs and clerical staff on one surgical team to run a successful audit system. Data were collected over a calendar month. This included time spent coding and typing endoscopy procedures, coding and typing operative procedures, and typing and signing discharge letters. The total amount of time spent to run the audit system for one Consultant surgeon for one calendar month was 5,168 min or 86.1 h. Greater than 50% of this time related to work performed by administrative staff. Only the intern and administrative staff spent more than 5% of their working week attending to work related to the audit. An integrated comprehensive audit system requires a very little time input by Consultant surgeons. Greater than 90% of the workload in running the audit was performed by the junior house doctors and administrative staff. The main financial implications for national audit implementation would relate to software and administrative staff recruitment. Implementation of the European Working Time Directive in Ireland may limit the time available for NCHD's to participate in clinical audit.

  1. The Time of Materiality

    Directory of Open Access Journals (Sweden)

    Estrid Sørensen

    2007-01-01

    Full Text Available While time and space form a classic duality in social science, this article demonstrates a perspective on time, space and materiality as a core trinity. As a prominent figure in contemporary discussions on materiality in the social sciences Science and Technology Studies (STS emphasizes relational approaches. STS however lacks a clear relational definition of materiality and tends instead to focus on the agency of entities, on for instance material agency. The article suggests a relational definition of materiality and notes that this move implies turning the question of the time of materiality into an empirical question. It is argued that relational materiality must be studied spatially, and thus a spatial approach describing patterns of relations is presented. Based on field work in a primary school classroom and computer lab, three materials are analyzed: the blackboard, a bed-loft and an online 3D virtual environment. The empirical descriptions depict three different materialities, and it is shown how time is formed differently in each of them. Time, it is argued, is an emergent and characterizing aspect of materialities as spatial formations. URN: urn:nbn:de:0114-fqs070122

  2. Time travel a history

    CERN Document Server

    Gleick, James

    2016-01-01

    From the acclaimed author of The Information and Chaos, here is a mind-bending exploration of time travel: its subversive origins, its evolution in literature and science, and its influence on our understanding of time itself. The story begins at the turn of the previous century, with the young H. G. Wells writing and rewriting the fantastic tale that became his first book and an international sensation: The Time Machine. It was an era when a host of forces was converging to transmute the human understanding of time, some philosophical and some technological: the electric telegraph, the steam railroad, the discovery of buried civilizations, and the perfection of clocks. James Gleick tracks the evolution of time travel as an idea that becomes part of contemporary culture—from Marcel Proust to Doctor Who, from Jorge Luis Borges to Woody Allen. He investigates the inevitable looping paradoxes and examines the porous boundary between pulp fiction and modern physics. Finally, he delves into a temporal shift that...

  3. SNS Diagnostics Timing Integration

    CERN Document Server

    Long, Cary D; Murphy, Darryl J; Pogge, James; Purcell, John D; Sundaram, Madhan

    2005-01-01

    The Spallation Neutron Source (SNS) accelerator systems will deliver a 1.0 GeV, 1.4 MW proton beam to a liquid mercury target for neutron scattering research. The accelerator complex consists of a 1 GeV linear accelerator, an accumulator ring and associated transport lines. The SNS diagnostics platform is PC-based running Windows XP Embedded for its OS and LabVIEW as its programming language. Coordinating timing among the various diagnostics instruments with the generation of the beam pulse is a challenging task that we have chosen to divide into three phases. First, timing was derived from VME based systems. In the second phase, described in this paper, timing pulses are generated by an in house designed PCI timing card installed in ten diagnostics PCs. Using fan-out modules, enough triggers were generated for all instruments. This paper describes how the Timing NAD (Network Attached Device) was rapidly developed using our NAD template, LabVIEW's PCI driver wizard, and LabVIEW Channel Access library. The NAD...

  4. Modelling bursty time series

    International Nuclear Information System (INIS)

    Vajna, Szabolcs; Kertész, János; Tóth, Bálint

    2013-01-01

    Many human-related activities show power-law decaying interevent time distribution with exponents usually varying between 1 and 2. We study a simple task-queuing model, which produces bursty time series due to the non-trivial dynamics of the task list. The model is characterized by a priority distribution as an input parameter, which describes the choice procedure from the list. We give exact results on the asymptotic behaviour of the model and we show that the interevent time distribution is power-law decaying for any kind of input distributions that remain normalizable in the infinite list limit, with exponents tunable between 1 and 2. The model satisfies a scaling law between the exponents of interevent time distribution (β) and autocorrelation function (α): α + β = 2. This law is general for renewal processes with power-law decaying interevent time distribution. We conclude that slowly decaying autocorrelation function indicates long-range dependence only if the scaling law is violated. (paper)

  5. Timing in a FLASH

    Science.gov (United States)

    Hoek, M.; Cardinali, M.; Corell, O.; Dickescheid, M.; Ferretti B., M. I.; Lauth, W.; Schlimme, B. S.; Sfienti, C.; Thiel, M.

    2017-12-01

    A prototype detector, called FLASH (Fast Light Acquiring Start Hodoscope), was built to provide precise Time-of-Flight (TOF) measurements and reference timestamps for detector setups at external beam lines. Radiator bars, made of synthetic fused silica, were coupled to a fast MCP-PMT with 64 channels and read out with custom electronics using Time-over-Threshold (TOT) for signal characterization. The TRB3 system, a high-precision TDC implemented in an FPGA, was used as data acquisition system. The performance of a system consisting of two FLASH units was investigated at a dedicated test experiment at the Mainz Microtron (MAMI) accelerator using its 855 MeV electron beam. The TOT measurement enabled time walk corrections and an overall TOF resolution of ∼70 ps could be achieved which translates into a resolution of ∼50 ps per FLASH unit. The intrinsic resolution of the frontend electronics including the TDC was measured to be less than 25 ps.

  6. Real-time radiography

    International Nuclear Information System (INIS)

    Bossi, R.H.; Oien, C.T.

    1981-01-01

    Real-time radiography is used for imaging both dynamic events and static objects. Fluorescent screens play an important role in converting radiation to light, which is then observed directly or intensified and detected. The radiographic parameters for real-time radiography are similar to conventional film radiography with special emphasis on statistics and magnification. Direct-viewing fluoroscopy uses the human eye as a detector of fluorescent screen light or the light from an intensifier. Remote-viewing systems replace the human observer with a television camera. The remote-viewing systems have many advantages over the direct-viewing conditions such as safety, image enhancement, and the capability to produce permanent records. This report reviews real-time imaging system parameters and components

  7. Time for memory

    DEFF Research Database (Denmark)

    Murakami, Kyoko

    2012-01-01

    This article is a continuous dialogue on memory triggered by Brockmeier’s (2010) article. I drift away from the conventionalization of the archive as a spatial metaphor for memory in order to consider the greater possibility of “time” for conceptualizing memory. The concept of time is central...... in terms of autobiographical memory. The second category of time is discussed, drawing on Augustine and Bergson amongst others. Bergson’s notion of duration has been considered as a promising concept for a better understanding of autobiographical memory. Psychological phenomena such as autobiographical...... memory should embrace not only spatial dimension, but also a temporal dimension, in which a constant flow of irreversible time, where multiplicity, momentarily, dynamic stability and becoming and emergence of novelty can be observed....

  8. Drug Retention Times

    Energy Technology Data Exchange (ETDEWEB)

    None, None

    2007-05-01

    The purpose of this monograph is to provide information on drug retention times in the human body. The information provided is based on plausible illegal drug use activities that might be engaged in by a recreational drug user. Based on anecdotal evidence, most people “party” during extended time away from the work environment. Therefore, the following scenarios were envisioned: (1) a person uses an illicit drug at a party on Saturday night (infrequent user); (2) a person uses a drug one time on Friday night and once again on Saturday night (infrequent user); and (3) a person uses a drug on Friday night, uses a drug twice on Saturday night, and once again on Sunday (frequent user).

  9. Agency, time and causality

    Directory of Open Access Journals (Sweden)

    Thomas eWidlok

    2014-11-01

    Full Text Available Cognitive Scientists interested in causal cognition increasingly search for evidence from non-WEIRD people but find only very few cross-cultural studies that specifically target causal cognition. This article suggests how information about causality can be retrieved from ethnographic monographs, specifically from ethnographies that discuss agency and concepts of time. Many apparent cultural differences with regard to causal cognition dissolve when cultural extensions of agency and personhood to non-humans are taken into account. At the same time considerable variability remains when we include notions of time, linearity and sequence. The article focuses on ethnographic case studies from Africa but provides a more general perspective on the role of ethnography in research on the diversity and universality of causal cognition.

  10. Visual time series analysis

    DEFF Research Database (Denmark)

    Fischer, Paul; Hilbert, Astrid

    2012-01-01

    We introduce a platform which supplies an easy-to-handle, interactive, extendable, and fast analysis tool for time series analysis. In contrast to other software suits like Maple, Matlab, or R, which use a command-line-like interface and where the user has to memorize/look-up the appropriate...... commands, our application is select-and-click-driven. It allows to derive many different sequences of deviations for a given time series and to visualize them in different ways in order to judge their expressive power and to reuse the procedure found. For many transformations or model-ts, the user may...... choose between manual and automated parameter selection. The user can dene new transformations and add them to the system. The application contains efficient implementations of advanced and recent techniques for time series analysis including techniques related to extreme value analysis and filtering...

  11. Into the Wild Time

    DEFF Research Database (Denmark)

    Berg Johansen, Christina

    2018-01-01

    I want to feel the temporalities I am theorizing and writing about. To feel, explore, be moved through, tugged under by my research subject, to not know where my explorations will take me. How does time appear when I take responsibility for it instead of placing it as and with the Other? Can my...... temporal research emerge in symbiotic play with other human and non-human entities? In this essay, I will share how a methodological breakdown opened to me a net of (auto-)ethnographic wo/anderings, dialogical interviews and performative time-laboratories. I do not know where I am headed, but every...... sensuous memory lies in store, waiting for its time....

  12. Time Domain Induced Polarization

    DEFF Research Database (Denmark)

    Fiandaca, Gianluca; Auken, Esben; Christiansen, Anders Vest

    2012-01-01

    Time-domain-induced polarization has significantly broadened its field of reference during the last decade, from mineral exploration to environmental geophysics, e.g., for clay and peat identification and landfill characterization. Though, insufficient modeling tools have hitherto limited the use...... of time-domaininduced polarization for wider purposes. For these reasons, a new forward code and inversion algorithm have been developed using the full-time decay of the induced polarization response, together with an accurate description of the transmitter waveform and of the receiver transfer function......, to reconstruct the distribution of the Cole-Cole parameters of the earth. The accurate modeling of the transmitter waveform had a strong influence on the forward response, and we showed that the difference between a solution using a step response and a solution using the accurate modeling often is above 100...

  13. Creating Space and Time

    DEFF Research Database (Denmark)

    Sandvik, Kjetil; Refslund Christensen, Dorthe

    referred to through accounts of ‘how death occurred’; second, a present time constituted by emotional and social stress and, thirdly, a wishful time or subjunctive mode articulating relational potentialities of these children and inventing memories with them (“I wish you would have lived to….”). We analyze......This paper explores relations between ritualized spatiality and the conceptions of time reflected in memorial websites such as the Danish site Mindet.dk, a narrowly framed, socially protective online community in which individuals can perform their grief through design of individual entries...... (‘memories’) for their deceased loved ones and get personal, social support in their mourning processes through communication with other mourners, through mutual appreciation of each other’s postings and through emotional labor reflected on the individual sites. The main focus in this paper is how online...

  14. Time Discretization Techniques

    KAUST Repository

    Gottlieb, S.

    2016-10-12

    The time discretization of hyperbolic partial differential equations is typically the evolution of a system of ordinary differential equations obtained by spatial discretization of the original problem. Methods for this time evolution include multistep, multistage, or multiderivative methods, as well as a combination of these approaches. The time step constraint is mainly a result of the absolute stability requirement, as well as additional conditions that mimic physical properties of the solution, such as positivity or total variation stability. These conditions may be required for stability when the solution develops shocks or sharp gradients. This chapter contains a review of some of the methods historically used for the evolution of hyperbolic PDEs, as well as cutting edge methods that are now commonly used.

  15. Fragments of Time

    DEFF Research Database (Denmark)

    Christiansen, Steen Ledet

    Time travel films necessarily fragment linear narratives, as scenes are revisited with differences from the first time we saw it. Popular films such as Back to the Future mine comedy from these visitations, but there are many different approaches. One extreme is Chris Marker's La Jetée - a film...... made almost completely of still images, recounting the end of the world. These stills can be viewed as fragments that have survived the end of the world and now provide the only access to the events that occured. Shane Carruth's Primer has a different approach to time travel, the narrative diegesis...... that is presented; how do we understand such films and to what extent is it even possible to make sense of a film that has no real beginning, middle or end?...

  16. Relational time in physics

    International Nuclear Information System (INIS)

    Assis, A.K.T.

    2011-01-01

    Full text: Isaac Newton (1642-1727) defended in his book Mathematical Principles of Natural Philosophy, also know as Principia, published in 1687, the utilization of absolute time in physics. According to him 'absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external'. Leibniz (1646-1716), on the other hand, was against this concept and proposed relative time to replace it: 'As for my opinion, I have said more than once, that I hold space to be something merely relative, as time is; that I hold it to be an order of coexistence, as time is an order of successions'. Leibniz ideas were accepted and developed by Ernst Mach (1838-1916) in his book The Science of Mechanics, published in 1883. In this work we consider the implementation of relational time, as proposed by Leibniz and Mach, and the consequences this implementation will mean for physics as a whole. We consider some specific examples related to mechanics (Newton's bucket experiment, the flattening of the Earth, Foucault's pendulum experiment) and to electromagnetism (Ampere's force between current carrying wires, an electric charge describing a Larmor radius due to a nearby large magnet, two charges orbiting around one another). We generalize these ideas considering the principle of physical proportions (PPP), according to which no absolute magnitudes should appear in the laws of physics. We present some laws satisfying this principle and others which do not comply with it. The laws which do not satisfy the PPP should be based upon incomplete theories. We present the consequences of complete theories complying with this fundamental principle of nature. (author)

  17. Relational time in physics

    Energy Technology Data Exchange (ETDEWEB)

    Assis, A.K.T. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil)

    2011-07-01

    Full text: Isaac Newton (1642-1727) defended in his book Mathematical Principles of Natural Philosophy, also know as Principia, published in 1687, the utilization of absolute time in physics. According to him 'absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external'. Leibniz (1646-1716), on the other hand, was against this concept and proposed relative time to replace it: 'As for my opinion, I have said more than once, that I hold space to be something merely relative, as time is; that I hold it to be an order of coexistence, as time is an order of successions'. Leibniz ideas were accepted and developed by Ernst Mach (1838-1916) in his book The Science of Mechanics, published in 1883. In this work we consider the implementation of relational time, as proposed by Leibniz and Mach, and the consequences this implementation will mean for physics as a whole. We consider some specific examples related to mechanics (Newton's bucket experiment, the flattening of the Earth, Foucault's pendulum experiment) and to electromagnetism (Ampere's force between current carrying wires, an electric charge describing a Larmor radius due to a nearby large magnet, two charges orbiting around one another). We generalize these ideas considering the principle of physical proportions (PPP), according to which no absolute magnitudes should appear in the laws of physics. We present some laws satisfying this principle and others which do not comply with it. The laws which do not satisfy the PPP should be based upon incomplete theories. We present the consequences of complete theories complying with this fundamental principle of nature. (author)

  18. Time and language.

    Science.gov (United States)

    Scharf, J H

    1982-01-01

    It is very interesting question whether time if a priori in mankind's thinking or whether it is a category which results from experience. Each human being has a memory so that he is able to distinguish between the past and the present, but not every language has a word expressing the common idea of time. In hunting and gathering populations such as Bushmen and Yumbri no one can state his own age. In chronobiology, the most important zeitgebers are the sun and the moon. Certain peasant peoples, such as the Santals and Mundas in India, even today use the same word to express sun, Sun-God, daylight, day, day-time, and hour. The first generalized idea of "time" seems to have arisen in the civilization of Old Mesopotamia. While the general meaning was still unknown to Sumerian, Accadian priest-astronomers presumably created the conception by generalization of the (Sumerian) foreign word itu(d) "mouth" and its mingling with the Accadian ittu(m) "sign (as an eclipse, monstrous birth, etc.), term, moment". We find the same root in the Etruscan itus "ides" from which it came as a loan-word into Latin (idus "ides"). Newton's term duratio can be found in earliest Iranian as yav- "yoke" and Vedic Indian as yugam "yoke" (i.e., a "bound" time). Some remarks are made concerning mankind's earliest chronobiological thinking where menstruation serves as a model. West African Kwa languages (predominantly Ewe), Old Indian, and early-classical chinese are evaluated. A brief survey is given of prehistoric peoples' migrations in terms of languages. The presentation concludes with an attempt to define time as an abstraction of abstractions, a fussy set (of ideas and definitions) in terms of post-classical set theory.

  19. Science of Time

    Science.gov (United States)

    Vedavyas

    A Multi-disciplinary Research into the Chronologies of Ancient Nations -- like the Vedas of India Rishies, the Chaldeans, Babylonians, Egyptians and the Chinese. Which traces how the "Measurement of Time" -- which began with the observations of sunrise and Sunset, Full-Moons, eclipses, the movement of stars and the Discovery of the Zodiac that starry pathway of sun in his annual Cycle of the 12-Zodiacal months, the Measurement of Time by planetary Cycles the Discovery of Astronomy and Symbolic or Kabalistic Astrology of the Bible's Old Testament; the Epics of Babylonians and 'Cosmic Cycles' of Chaldeans and Egyptians also the Ancient "Four Yugas" or Hindu Vedic Cycles.

  20. Time Series Momentum

    DEFF Research Database (Denmark)

    Moskowitz, Tobias J.; Ooi, Yao Hua; Heje Pedersen, Lasse

    2012-01-01

    We document significant “time series momentum” in equity index, currency, commodity, and bond futures for each of the 58 liquid instruments we consider. We find persistence in returns for one to 12 months that partially reverses over longer horizons, consistent with sentiment theories of initial...... under-reaction and delayed over-reaction. A diversified portfolio of time series momentum strategies across all asset classes delivers substantial abnormal returns with little exposure to standard asset pricing factors and performs best during extreme markets. Examining the trading activities...

  1. Applied time series analysis

    CERN Document Server

    Woodward, Wayne A; Elliott, Alan C

    2011-01-01

    ""There is scarcely a standard technique that the reader will find left out … this book is highly recommended for those requiring a ready introduction to applicable methods in time series and serves as a useful resource for pedagogical purposes.""-International Statistical Review (2014), 82""Current time series theory for practice is well summarized in this book.""-Emmanuel Parzen, Texas A&M University""What an extraordinary range of topics covered, all very insightfully. I like [the authors'] innovations very much, such as the AR factor table.""-David Findley, U.S. Census Bureau (retired)""…

  2. Predicting chaotic time series

    International Nuclear Information System (INIS)

    Farmer, J.D.; Sidorowich, J.J.

    1987-01-01

    We present a forecasting technique for chaotic data. After embedding a time series in a state space using delay coordinates, we ''learn'' the induced nonlinear mapping using local approximation. This allows us to make short-term predictions of the future behavior of a time series, using information based only on past values. We present an error estimate for this technique, and demonstrate its effectiveness by applying it to several examples, including data from the Mackey-Glass delay differential equation, Rayleigh-Benard convection, and Taylor-Couette flow

  3. Competitive Moves over Time

    DEFF Research Database (Denmark)

    Antero, Michelle; Hedman, Jonas; Henningsson, Stefan

    2014-01-01

    its viability to survive in the marketplace. The study begins with a review of sourcing literature to position the Red Queen theory within the sourcing literature. It subsequently applies the framework to a case study of SAP AG to illustrate how sourcing strategies changed over time in response...... the firm; (c) organizations are reflexive and over time develop competitive hysteresis which allows them to become stronger competitors. In the case of SAP AG, various sourcing arrangements were selected over its 40-year history to respond to technological and market changes....

  4. Discounting in Time

    DEFF Research Database (Denmark)

    Fahrenberg, Uli; Larsen, Kim Guldstrand

    2009-01-01

    This paper deals with the issue of discounting in weighted timed transition systems. Discounting provides a way to model optimal-cost problems for infinite runs and has applications in optimal scheduling and other areas. We show that when postulating a certain natural additivity property for the ......This paper deals with the issue of discounting in weighted timed transition systems. Discounting provides a way to model optimal-cost problems for infinite runs and has applications in optimal scheduling and other areas. We show that when postulating a certain natural additivity property...

  5. Discrete-Time Systems

    Indian Academy of Sciences (India)

    We also describe discrete-time systems in terms of difference ... A more modern alternative, especially for larger systems, is to convert ... In other words, ..... picture?) State-variable equations are also called state-space equations because the ...

  6. Time-Darts

    DEFF Research Database (Denmark)

    Jørgensen, Kenneth Yrke; Larsen, Kim Guldstrand; Srba, Jiri

    2012-01-01

    Symbolic data structures for model checking timed systems have been subject to a significant research, with Difference Bound Matrices (DBMs) still being the preferred data structure in several mature verification tools. In comparison, discretization offers an easy alternative, with all operations...

  7. Time and Logic

    DEFF Research Database (Denmark)

    Øhrstrøm, Peter

    2009-01-01

    's notion of branching time is analysed. It is argued that Prior can be criticized for identifying 'plain future'. Finally, Prior's four grades of tense-logical involvement are introduced and discussed. It is argued that the third grade is the most attractive form a philosophical point of view....

  8. Time in the Making

    DEFF Research Database (Denmark)

    Dirckinck-Holmfeld, Katrine Remmen

    ? These are research questions Katrine Dirckinck - Holmfeld explores in the artistic research project Time in the Making: Rehearsing Reparative Critical Practices. Through the development of video installations Leap into Colour (20 12 - 2015) and movement (2012) and in dialogue with the work of artists Rania & Raed...

  9. Space-time structure

    CERN Document Server

    Schrödinger, Erwin

    1985-01-01

    In response to repeated requests this classic book on space-time structure by Professor Erwin Schrödinger is now available in the Cambridge Science Classics series. First published in 1950, and reprinted in 1954 and 1960, this lucid and profound exposition of Einstein's 1915 theory of gravitation still provides valuable reading for students and research workers in the field.

  10. Hard times; Schwere Zeiten

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, Markus

    2012-10-02

    The prices of silicon and solar wafers keep dropping. According to market research specialist IMS research, this is the result of weak traditional solar markets and global overcapacities. While many manufacturers are facing hard times, big producers of silicon are continuing to expand.

  11. Time reversal communication system

    Science.gov (United States)

    Candy, James V.; Meyer, Alan W.

    2008-12-02

    A system of transmitting a signal through a channel medium comprises digitizing the signal, time-reversing the digitized signal, and transmitting the signal through the channel medium. The channel medium may be air, earth, water, tissue, metal, and/or non-metal.

  12. Smartphones and Time Zones

    Science.gov (United States)

    Baird, William; Secrest, Jeffery; Padgett, Clifford; Johnson, Wayne; Hagrelius, Claire

    2016-01-01

    Using the Sun to tell time is an ancient idea, but we can take advantage of modern technology to bring it into the 21st century for students in astronomy, physics, or physical science classes. We have employed smartphones, Google Earth, and 3D printing to find the moment of local noon at two widely separated locations. By reviewing GPS…

  13. Biophase equilibration times.

    Science.gov (United States)

    Veng-Pedersen, P; Mandema, J W; Danhof, M

    1991-09-01

    Various methods for describing how quickly a drug equilibrates at the biophase are proposed. The biophase equilibration time (BET) is the time it takes the biophase drug level to reach a given percentage (p) of its predicted steady state in a drug administration that leads to a steady-state condition. The time to reach biophase equilibrium may be defined as the BET value for p = 95, and the 50% biophase equilibration time is obtained when p = 50. Biophase equilibration profiles (BEPs), obtained by plotting p versus BET, give a dynamic representation of the approach to equilibrium and may serve as an indicator of the rate of drug delivery to the biophase. A pharmacodynamic system analysis method is proposed to determine BETs and BEPs from the biophase conduction function. The approach is demonstrated using pharmacodynamic data from the CNS effect of amobarbital evaluated by an aperiodic analysis of EEG recordings. The relevance of the BET and/or BEP principles in optimal computer-controlled drug infusion, drug design, and evaluation of targeted drug delivery is discussed. Both vascular and extravascular drug administrations are considered in the analysis.

  14. Czechs and Leisure Time

    Czech Academy of Sciences Publication Activity Database

    Šamanová, Gabriela; Červenka, Jan

    2011-01-01

    Roč. 9, 7-8 (2011), s. 1-3 ISSN 1214-1720 Institutional research plan: CEZ:AV0Z70280505 Keywords : public opinion * leisure time Subject RIV: AO - Sociology, Demography http://www.socioweb.cz/upl/editorial/download/192_SOCIOWEB_07_08_2011.pdf

  15. Aid Supplies Over Time

    DEFF Research Database (Denmark)

    Jones, Edward Samuel

    2015-01-01

    of data spanning nearly 50 years, this paper uses panel cointegration techniques to consider these issues. The analysis provides clear evidence for heterogeneity both between donors and over time, bandwagon effects, and a growing influence of security considerations in aid provision. Domestic...... macroeconomic shocks have a moderate but delayed effect on aid disbursements....

  16. Sedentary Time in Children

    DEFF Research Database (Denmark)

    Atkin, Andrew J; Ekelund, Ulf; Møller, Niels Christian

    2013-01-01

    PURPOSE: Accelerometry is increasingly being used to assess sedentary time in epidemiological studies, yet the most appropriate means of processing this data remains uncertain. This cross-sectional study examined the influence of selected accelerometer cutpoints and non-wear criteria on associati...

  17. The dance of time

    CERN Document Server

    Aparici, Irene; Brokenbrow, Jon

    2014-01-01

    Winner at the 2014 Living Now Book Awards The Dance of Time is a book full of imagination and information, which will be useful for parents and teachers looking to accompany children on a different kind of journey through our solar system. Guided Reading Level: P, Lexile Level: 830L.

  18. Scheduling with Time Lags

    NARCIS (Netherlands)

    X. Zhang (Xiandong)

    2010-01-01

    textabstractScheduling is essential when activities need to be allocated to scarce resources over time. Motivated by the problem of scheduling barges along container terminals in the Port of Rotterdam, this thesis designs and analyzes algorithms for various on-line and off-line scheduling problems

  19. Keeping time - Performing Place

    DEFF Research Database (Denmark)

    Dvinge, Anne Christine

    2012-01-01

    Candace Allen’s novel Valaida (2004) illustrates the migratory patterns of early 20th century jazz music and musicians, positing the art form and its performers as “heterotopians”; simultaneously in and outside of the power relations of hegemonic time-space compression, travelling in an alternate...

  20. In Time of War.

    Science.gov (United States)

    Becker, Patti Clayton

    2003-01-01

    Examines the role of libraries, particularly public libraries, in times of war. Discusses similarities between responses after World War Two and the September 11, 2001 attacks; government restrictions on information; American Library Association responses, including propaganda and libraries; and the library and the community. (LRW)

  1. Make time to move

    Science.gov (United States)

    ... or after work. Schedule your exercise. Make getting exercise just as important as your other appointments. Set aside time in ... update 04-02-18. Related MedlinePlus Health Topics ... among the first to achieve this important distinction for online health information and services. Learn ...

  2. DELPHI time projection chamber

    CERN Multimedia

    1989-01-01

    The time projection chamber is inserted inside the central detector of the DELPHI experiment. Gas is ionised in the chamber as a charged particle passes through, producing an electric signal from which the path of the particle can be found. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  3. On Space and Time

    Science.gov (United States)

    Majid, Shahn; Polkinghorne, With contributions by John; Penrose, Roger; Taylor, Andrew; Connes, Alain; Heller, Michael

    2012-03-01

    Preface; 1. The dark universe A. N. Taylor; 2. Quantum spacetime and physical reality S. Majid; 3. Causality, quantum theory and cosmology R. Penrose; 4. On the fine structure of spacetime A. Connes; 5. Where physics meets metaphysics M. Heller; 6. The nature of time J. C. Polkinghorne; Index.

  4. Travel time reliability modeling.

    Science.gov (United States)

    2011-07-01

    This report includes three papers as follows: : 1. Guo F., Rakha H., and Park S. (2010), "A Multi-state Travel Time Reliability Model," : Transportation Research Record: Journal of the Transportation Research Board, n 2188, : pp. 46-54. : 2. Park S.,...

  5. Time processing in dyscalculia

    Directory of Open Access Journals (Sweden)

    marinella eCappelletti

    2011-12-01

    Full Text Available To test whether atypical number development may affect other types of quantity processing, we investigated temporal discrimination in adults with developmental dyscalculia (DD. This also allowed us to test whether (1 number and time may be sub-served by a common quantity system or decision mechanisms –in which case they may both be impaired, or (2 whether number and time are distinct –and therefore they may dissociate. Participants judged which of two successively presented horizontal lines was longer in duration, the first line being preceded by either a small or a large number prime (‘1’ or ‘9’ or by a neutral symbol (‘#’, or in third task decide which of two Arabic numbers (either ‘1’, ‘5’, ’9’ lasted longer. Results showed that (i DD’s temporal discriminability was normal as long as numbers were not part of the experimental design even as task-irrelevant stimuli; however (ii task-irrelevant numbers dramatically disrupted DD’s temporal discriminability, the more their salience increased, though the actual magnitude of the numbers had no effect; and in contrast (iii controls’ time perception was robust to the presence of numbers but modulated by numerical quantity such that small number primes or numerical stimuli made durations appear shorter than veridical and the opposite for larger numerical prime or numerical stimuli. This study is the first to investigate continuous quantity as time in a population with a congenital number impairment and to show that atypical development of numerical competence leaves continuous quantity processing spared. Our data support the idea of a partially shared quantity system across numerical and temporal dimensions, which allows dissociations and interactions among dimensions; furthermore, they suggest that impaired number in DD is unlikely to originate from systems initially dedicated to continuous quantity processing like time.

  6. Stop wasting valuable time.

    Science.gov (United States)

    Mankins, Michael C

    2004-09-01

    Companies routinely squander their most precious resource--the time of their top executives. In the typical company, senior executives meet to discuss strategy for only three hours a month. And that time is poorly spent in diffuse discussions never even meant to result in any decision. The price of misused executive time is high. Delayed strategic decisions lead to overlooked waste and high costs, harmful cost reductions, missed new product and business development opportunities, and poor long-term investments. But a few deceptively simple changes in the way top management teams set agendas and structure team meetings can make an enormous difference in their effectiveness. Efficient companies use seven techniques to make the most of the time their top executives spend together. They keep strategy meetings separate from meetings focused on operations. They explore issues through written communications before they meet, so that meeting time is used solely for reaching decisions. In setting agendas, they rank the importance of each item according to its potential to create value for the company. They seek to get issues not only on, but also off, the agenda quickly, keeping to a clear implementation timetable. They make sure they have considered all viable alternatives before deciding a course of action. They use a common language and methodology for reaching decisions. And they insist that, once a decision is made, they stick to it--that there be no more debate or mere grudging compliance. Once leadership teams get the basics right, they can make more fundamental changes in the way they work together. Strategy making can be transformed from a series of fragmented and unproductive events into a streamlined, effective, and continuing management dialogue. In companies that have done this, management meetings aren't a necessary evil; they're a source of real competitive advantage.

  7. Tracking change over time

    Science.gov (United States)

    ,

    2011-01-01

    Landsat satellites capture images of Earth from space-and have since 1972! These images provide a long-term record of natural and human-induced changes on the global landscape. Comparing images from multiple years reveals slow and subtle changes as well as rapid and devastating ones. Landsat images are available over the Internet at no charge. Using the free software MultiSpec, students can track changes to the landscape over time-just like remote sensing scientists do! The objective of the Tracking Change Over Time lesson plan is to get students excited about studying the changing Earth. Intended for students in grades 5-8, the lesson plan is flexible and may be used as a student self-guided tutorial or as a teacher-led class lesson. Enhance students' learning of geography, map reading, earth science, and problem solving by seeing landscape changes from space.

  8. Route around real time

    International Nuclear Information System (INIS)

    Terrier, Francois

    1996-01-01

    The greater and greater autonomy and complexity asked to the control and command systems lead to work on introducing techniques such as Artificial Intelligence or concurrent object programming in industrial applications. However, while the critical feature of these systems impose to control the dynamics of the proposed solutions, their complexity often imposes a high adaptability to a partially modelled environment. The studies presented start from low level control and command systems to more complex applications at higher levels, such as 'supervision systems'. Techniques such as temporal reasoning and uncertainty management are proposed for the first studies, while the second are tackled with programming techniques based on the real time object paradigm. The outcomes of this itinerary crystallize on the ACCORD project which targets to manage - on the whole life cycle of a real time application - these two problematics, sometimes antagonistic: control of the dynamics and adaptivity. (author) [fr

  9. Time Use on Trains

    DEFF Research Database (Denmark)

    Bjørner, Thomas

    2016-01-01

    . The passengers create a travel space in which they make dynamic shifts in different kinds of activities: media use, media non-use, social interactions and non-social interactions. Passengers expect the train operator to provide the travel space for different activities (including the possibility of mobile......This study explores how travel time is used and how passengers conceptualise travel time in Danish intercity trains and intercity fast trains. The new contribution to the literature this study can offer is in the inclusion of all kinds of passengers in the different compartments to understand train...... travel as a dynamic act of moving with shifts in activities. A mixed-method approach is used with self-completed questionnaires, frequency observations, shadowing observations and interviews. The findings reveal that the train passengers’ acts on the move are framed by both macro- and microstructures...

  10. This time it's different

    International Nuclear Information System (INIS)

    Leder, Frederic; Shapiro, Judith N.

    2008-01-01

    There is virtual agreement among geologists that world production of conventional oil will peak at some point in the future. Oil, after all, is a finite resource, while demand will only grow over time. Geologists disagree, however, exactly when the peak will occur. Using data from the International Energy Agency, the US Department of Energy, the Association for the Study of Peak Oil and Gas, and petroleum industry sources, we argue that conventional oil production will reach a worldwide maximum within the next 5-10 years, earlier than generally estimated, thus leaving a very short time frame within which to plan for conversion to alternative sources of energy. Unless planning is initiated immediately, the United States and other Western democracies will see their positions in the global economy undercut as military conflicts over limited energy resources increase, and wealth and power are shifted to authoritarian regimes in Russia, Venezuela, Africa and the Middle East

  11. JKJ accelerator timing system

    International Nuclear Information System (INIS)

    Ohmori, C.; Mori, Y.; Yoshii, M.; Yamamoto, M.

    2001-01-01

    The JKJ (JAERl-KEK Joint Project) accelerator complex consists of the linear accelerator, 3 GeV and 50 GeV synchrotrons. To minimize the beam loss during the beam transfer from the 3 GeV synchrotron to the 50 GeV one, the synchronization of the two RF system of the rings is very important. To reduce the background from the high and low momentum neutron, the neutron beam chopper will be employed. The 3 GeV RF will be also synchronized to the chopper timing when the beam goes to the neutron facility. The whole timing control system of these accelerators and chopper will be described. (author)

  12. No sliding in time

    International Nuclear Information System (INIS)

    Shtengel, Kirill; Nayak, Chetan; Bishara, Waheb; Chamon, Claudio

    2005-01-01

    In this letter, we analyse the following apparent paradox: as has been recently proved by Hastings (2004 Phys. Rev. 69 104431), under a general set of conditions, if a local Hamiltonian has a spectral gap above its (unique) ground state (GS), all connected equal-time correlation functions of local operators decay exponentially with distance. On the other hand, statistical mechanics provides us with examples of 3D models displaying so-called sliding phases (O'Hern et al 1999 Phys. Rev. Lett. 83 2745) which are characterized by the algebraic decay of correlations within 2D layers and exponential decay in the third direction. Interpreting this third direction as time would imply a gap in the corresponding (2+1)D quantum Hamiltonian which would seemingly contradict Hastings' theorem. The resolution of this paradox lies in the non-locality of such a quantum Hamiltonian. (letter to the editor)

  13. Multiple time scale dynamics

    CERN Document Server

    Kuehn, Christian

    2015-01-01

    This book provides an introduction to dynamical systems with multiple time scales. The approach it takes is to provide an overview of key areas, particularly topics that are less available in the introductory form.  The broad range of topics included makes it accessible for students and researchers new to the field to gain a quick and thorough overview. The first of its kind, this book merges a wide variety of different mathematical techniques into a more unified framework. The book is highly illustrated with many examples and exercises and an extensive bibliography. The target audience of this  book are senior undergraduates, graduate students as well as researchers interested in using the multiple time scale dynamics theory in nonlinear science, either from a theoretical or a mathematical modeling perspective. 

  14. The Best of Times.

    Science.gov (United States)

    Dwyer, Johanna T

    2017-08-21

    I came of age as a nutrition scientist during the best of times-years that spanned a rapidly changing world of food and nutrition science, politics, and policy that greatly broadened the specialty and its influence on public affairs. I followed the conventional route in academe, working my way up the academic ladder in Boston from a base first in a school of public health and later in a teaching hospital and medical school, interspersed with stints in Washington, DC. Thus I tell a tale of two cities. Those were the best of times because nutrition science and policy converged and led to important policies and programs that shaped the field for the next 50 years.

  15. Real time production optimization

    Energy Technology Data Exchange (ETDEWEB)

    Saputelli, Luigi; Otavio, Joao; Araujo, Turiassu; Escorcia, Alvaro [Halliburton, Houston, TX (United States). Landmark Division

    2004-07-01

    Production optimization encompasses various activities of measuring, analyzing, modeling, prioritizing and implementing actions to enhance productivity of a field. We present a state-of-the-art framework for optimizing production on a continuous basis as new sensor data is acquired in real time. Permanently acquired data is modeled and analyzed in order to create predictive models. A model based control strategy is used to regulate well and field instrumentation. The optimum field operating point, which changes with time, satisfies the maximum economic return. This work is a starting point for further development in automatic, intelligent reservoir technologies which get the most out of the abilities of permanent, instrumented wells and remotely activated downhole completions. The strategy, tested with history-matched data from a compartmentalised giant field, proved to reduce operating costs while increasing oil recovery by 27% in this field. (author)

  16. [Time, cultures, and coexistence].

    Science.gov (United States)

    Elchardus, M; Glorieux, I; Scheys, M

    1987-06-01

    "In this essay, the authors try to illustrate the relevance of the sociology of time for the study of migration and inter-cultural relations. It is argued that by taking the time-dimension more explicitly into account, our insights in the dynamics of these relations can be [improved].... In connection with international migration processes, this relationship appears to be influenced by at least six different factors: 1) the sudden transition from a rural to an urban, industrial environment; 2) the perspective of the return to the homeland; 3) the confrontation with the culture of the host country and with other migrants' cultures; 4) the religious, ideological and political developments in the homeland; 5) the reactions of the host country and the problems these create; 6) the minority position of the migrants." (SUMMARY IN ENG) excerpt

  17. Real time urbanism

    Directory of Open Access Journals (Sweden)

    Ana Ruiz Varona

    2012-12-01

    Full Text Available Nowadays, given the technological revolution of the society of information, the administrative management of the cities faces a new problem not as related to the projection of the urban space as to the capacity of controlling and measuring the process of direct and centralized production of the cities by part of some non-homogeneous social multitudes, in a hyper-accelerated time towards instantaneity. Against libertarian apologies of the new “participative urbanisms”, the article puts forward a discourse that shows the lost associated to the new problem of temporal instantaneity. In this regard we claim new process of mediation that allow administrations and urbanist monitoring the production of the city. To that end, a previous and necessary step will be the redefinition of the role of a new real time urbanist.

  18. Gravity, Time, and Lagrangians

    Science.gov (United States)

    Huggins, Elisha

    2010-01-01

    Feynman mentioned to us that he understood a topic in physics if he could explain it to a college freshman, a high school student, or a dinner guest. Here we will discuss two topics that took us a while to get to that level. One is the relationship between gravity and time. The other is the minus sign that appears in the Lagrangian. (Why would one…

  19. Real time falling leaves

    OpenAIRE

    Vázquez Alcocer, Pere Pau; Balsa, Marcos

    2007-01-01

    There is a growing interest in simulating natural phenomena in computer graphics applications. Animating natural scenes in real time is one of the most challenging problems due to the inherent complexity of their structure, formed by millions of geometric entities, and the interactions that happen within. An example of natural scenario that is needed for games or simulation programs are forests. Forests are difficult to render because the huge amount of geometric entities and the large amount...

  20. Uniqueness in time measurement

    International Nuclear Information System (INIS)

    Lorenzen, P.

    1981-01-01

    According to P. Janich a clock is defined as an apparatus in which a point ( hand ) is moving uniformly on a straight line ( path ). For the definition of uniformly first the scaling (as a constant ratio of velocities) is defined without clocks. Thereafter the uniqueness of the time measurement can be proved using the prove of scaling of all clocks. But the uniqueness can be defined without scaling, as it is pointed out here. (orig.) [de

  1. Time dependent accessibility

    OpenAIRE

    Kaza, Nikhil

    2015-01-01

    Many place based accessibility studies ignore the time component. Relying on theoretical frameworks that treat distance between two fixed points as constant, these methods ignore the diurnal and seasonal changes in accessibility. Network distances between two nodes are dependent on the network structure and weight distribution on the edges. These weights can change quite frequently and the network structure itself is subject to modification because of availability and unavailability of links ...

  2. Time to move on?

    CERN Document Server

    Ellis, John

    2017-01-01

    Cosmology and particle physics have long been dominated by theoretical paradigms: Einstein's general theory of relativity in cosmology and the Standard Model of particle physics. The time may have come for paradigm shifts. Does cosmological inflation require a modification of Einstein's gravity? Have experiments at the LHC discovered a new particle beyond the Standard Model? It is premature to answer these questions, but we theorists can dream about the possibilities.

  3. Galileo Timing Applications

    Science.gov (United States)

    2007-11-01

    public bodies like university and research institutes. The user community analysis also includes a market analysis performed by a specialized company to... companies and public institutions (e.g., universities, research laboratories) that work in several different application domains in order to virtually...Summary of application domains for the use of time in cryptography. B2G B2B B2C Applications Military waypoints, judicial reports, construction

  4. Making time to talk.

    Science.gov (United States)

    2016-09-01

    NHS Employers has updated its people performance management toolkit, which now includes links to new guidance and resources. The toolkit encourages managers to 'make time to talk' about performance with staff, provides practical support, increases managers' knowledge about what good performance management is, and aims to increase their confidence in dealing with associated challenges, such as what to do if a team member is underperforming and how to give constructive feedback.

  5. Real Time Strategy Language

    OpenAIRE

    Hayes, Roy; Beling, Peter; Scherer, William

    2014-01-01

    Real Time Strategy (RTS) games provide complex domain to test the latest artificial intelligence (AI) research. In much of the literature, AI systems have been limited to playing one game. Although, this specialization has resulted in stronger AI gaming systems it does not address the key concerns of AI researcher. AI researchers seek the development of AI agents that can autonomously interpret learn, and apply new knowledge. To achieve human level performance, current AI systems rely on game...

  6. Real Time Baseball Database

    Science.gov (United States)

    Fukue, Yasuhiro

    The author describes the system outline, features and operations of "Nikkan Sports Realtime Basaball Database" which was developed and operated by Nikkan Sports Shimbun, K. K. The system enables to input numerical data of professional baseball games as they proceed simultaneously, and execute data updating at realtime, just-in-time. Other than serving as supporting tool for prepareing newspapers it is also available for broadcasting media, general users through NTT dial Q2 and others.

  7. Real Time Processing

    CERN Multimedia

    CERN. Geneva; ANDERSON, Dustin James; DOGLIONI, Caterina

    2015-01-01

    The LHC provides experiments with an unprecedented amount of data. Experimental collaborations need to meet storage and computing requirements for the analysis of this data: this is often a limiting factor in the physics program that would be achievable if the whole dataset could be analysed. In this talk, I will describe the strategies adopted by the LHCb, CMS and ATLAS collaborations to overcome these limitations and make the most of LHC data: data parking, data scouting, and real-time analysis.

  8. Strange science takes time

    CERN Multimedia

    2008-01-01

    The late astronomer Carl Sagan popularized the saying that "extraordinary claims require extraordinary evidence," in reference to reports of alien visitations. Generating low-cost commercial fusion power, isolating antimatter and tracing reverse-time causality aren't as far out there as UFOs, but a similar rule might well apply: Extraordinary science requires extraordinary effort. With that in mind, here's a progress report on three extraordinary science projects that have popped up in the news...

  9. Space, time and causality

    International Nuclear Information System (INIS)

    Lucas, J.R.

    1984-01-01

    Originating from lectures given to first year undergraduates reading physics and philosophy or mathematics and philosophy, formal logic is applied to issues and the elucidation of problems in space, time and causality. No special knowledge of relativity theory or quantum mechanics is needed. The text is interspersed with exercises and each chapter is preceded by a suggested 'preliminary reading' and followed by 'further reading' references. (U.K.)

  10. Time processing in dyscalculia.

    Science.gov (United States)

    Cappelletti, Marinella; Freeman, Elliot D; Butterworth, Brian L

    2011-01-01

    To test whether atypical number development may affect other types of quantity processing, we investigated temporal discrimination in adults with developmental dyscalculia (DD). This also allowed us to test whether number and time may be sub-served by a common quantity system or decision mechanisms: if they do, both should be impaired in dyscalculia, but if number and time are distinct they should dissociate. Participants judged which of two successively presented horizontal lines was longer in duration, the first line being preceded by either a small or a large number prime ("1" or "9") or by a neutral symbol ("#"), or in a third task participants decided which of two Arabic numbers (either "1," "5," "9") lasted longer. Results showed that (i) DD's temporal discriminability was normal as long as numbers were not part of the experimental design, even as task-irrelevant stimuli; however (ii) task-irrelevant numbers dramatically disrupted DD's temporal discriminability the more their salience increased, though the actual magnitude of the numbers had no effect; in contrast (iii) controls' time perception was robust to the presence of numbers but modulated by numerical quantity: therefore small number primes or numerical stimuli seemed to make durations appear shorter than veridical, but longer for larger numerical prime or numerical stimuli. This study is the first to show spared temporal discrimination - a dimension of continuous quantity - in a population with a congenital number impairment. Our data reinforce the idea of a partially shared quantity system across numerical and temporal dimensions, which supports both dissociations and interactions among dimensions; however, they suggest that impaired number in DD is unlikely to originate from systems initially dedicated to continuous quantity processing like time.

  11. About tunnelling times

    International Nuclear Information System (INIS)

    Olkhovsky, V.S.; Recami, E.

    1991-08-01

    In this paper, first we critically analyse the main theoretical definitions and calculations of the sub-barrier tunnelling and reflection times. Secondly, we propose a new, physically sensible definition of such durations, on the basis of a recent general formalism (already tested for other types of quantum collisions). At last, we discuss some results regarding temporal evolution of the tunnelling processes, and in particular the ''particle'' speed during tunnelling. (author). 36 refs, 1 fig

  12. Timing Foreign Exchange Markets

    Directory of Open Access Journals (Sweden)

    Samuel W. Malone

    2016-03-01

    Full Text Available To improve short-horizon exchange rate forecasts, we employ foreign exchange market risk factors as fundamentals, and Bayesian treed Gaussian process (BTGP models to handle non-linear, time-varying relationships between these fundamentals and exchange rates. Forecasts from the BTGP model conditional on the carry and dollar factors dominate random walk forecasts on accuracy and economic criteria in the Meese-Rogoff setting. Superior market timing ability for large moves, more than directional accuracy, drives the BTGP’s success. We explain how, through a model averaging Monte Carlo scheme, the BTGP is able to simultaneously exploit smoothness and rough breaks in between-variable dynamics. Either feature in isolation is unable to consistently outperform benchmarks throughout the full span of time in our forecasting exercises. Trading strategies based on ex ante BTGP forecasts deliver the highest out-of-sample risk-adjusted returns for the median currency, as well as for both predictable, traded risk factors.

  13. Digital time-interpolator

    International Nuclear Information System (INIS)

    Schuller, S.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

    1990-01-01

    This report presents a description of the design of a digital time meter. This time meter should be able to measure, by means of interpolation, times of 100 ns with an accuracy of 50 ps. In order to determine the best principle for interpolation, three methods were simulated at the computer with a Pascal code. On the basis of this the best method was chosen and used in the design. In order to test the principal operation of the circuit a part of the circuit was constructed with which the interpolation could be tested. The remainder of the circuit was simulated with a computer. So there are no data available about the operation of the complete circuit in practice. The interpolation part however is the most critical part, the remainder of the circuit is more or less simple logic. Besides this report also gives a description of the principle of interpolation and the design of the circuit. The measurement results at the prototype are presented finally. (author). 3 refs.; 37 figs.; 2 tabs

  14. The sun in time

    International Nuclear Information System (INIS)

    Sonett, C.P.; Giampapa, M.S.; Matthews, M.S.

    1991-01-01

    Various papers on solar science are presented. The topics considered include: variability of solar irradiance, sunspot number, solar diameter, and solar wind properties; theory of luminosity and radius variations; standard solar models; the sun and the IMF; variations of cosmic-ray flux with time; accelerated particles in solar flares; solar cosmic ray fluxes during the last 10 million yrs; solar neutrinos and solar history; time variations of Be-10 and solar activity; solar and terrestrial components of the atmospheric C-14 variation spectrum; solar flare heavy-ion tracks in extraterrestrial objects. Also addressed are: the faint young sun problem; atmospheric responses to solar irradiation; quaternary glaciations; solar-terrestrial relationships in recent sea sediments; magnetic history of the sun; pre- and main-sequence evolution of solar activity; magnetic activity in pre-main-sequence stars; classical T Tauri stars; relict magnetism of meteorites; luminosity variability of solar-type stars; evolution of angular momentum in solar-mass stars; time evolution of magnetic fields on solarlike stars

  15. Extending over time

    DEFF Research Database (Denmark)

    Christensen, Tanya Karoli; Jensen, Torben Juel; Christensen, Marie Herget

    recorded twice (in the 1980s and again in the 2000s). This allows us to study language change in three ways: in apparent time and in real time as both panel and trend studies. The study is based on a 1,3 M word corpus of spoken Danish, comprising 125 recordings with 84 Co-penhagen speakers, born 1942......-speakers’ treatment of the utterance with respect to conversational turn taking. This coding allows us to follow grammaticalization processes of the different GE types based on distribu-tional and mixed models analyses. A marked difference between Danish and English is the fact that very few variants are headed...... that variants with sådan noget, though prevalent across the board, may be stigmatized, since they are produced mainly by young WC males, and exhibit an overall drop in frequency over time. In our paper, we will use GEs in Danish as a case study for evaluating prevailing assumptions about the relationship...

  16. Generalized Canonical Time Warping.

    Science.gov (United States)

    Zhou, Feng; De la Torre, Fernando

    2016-02-01

    Temporal alignment of human motion has been of recent interest due to its applications in animation, tele-rehabilitation and activity recognition. This paper presents generalized canonical time warping (GCTW), an extension of dynamic time warping (DTW) and canonical correlation analysis (CCA) for temporally aligning multi-modal sequences from multiple subjects performing similar activities. GCTW extends previous work on DTW and CCA in several ways: (1) it combines CCA with DTW to align multi-modal data (e.g., video and motion capture data); (2) it extends DTW by using a linear combination of monotonic functions to represent the warping path, providing a more flexible temporal warp. Unlike exact DTW, which has quadratic complexity, we propose a linear time algorithm to minimize GCTW. (3) GCTW allows simultaneous alignment of multiple sequences. Experimental results on aligning multi-modal data, facial expressions, motion capture data and video illustrate the benefits of GCTW. The code is available at http://humansensing.cs.cmu.edu/ctw.

  17. Use of TIME: Time perspective intervention of motivation enhancement.

    NARCIS (Netherlands)

    Peetsma, T.; Van der Veen, I.; Schuitema, J.; Kostić, A.; Chadee, D.

    2017-01-01

    Considering the association between time perspective and motivated learning, the authors draw on time perspective theory in the development of an intervention to increase adolescent students’ motivation for school: TIME (Time perspective Intervention of Motivation Enhancement). Four studies centered

  18. Commission 31: Time

    Science.gov (United States)

    Matsakis, Demetrios; Defraigne, Pascale; Hosokawa, M.; Leschiutta, S.; Petit, G.; Zhai, Z.-C.

    2007-03-01

    The most intensely discussed and controversial issue in time keeping has been the proposal before the International Telecommunications Union (ITU) to redefine Coordinated Universal Time (UTC) so as to replace leap seconds by leap hours. Should this proposal be adopted, the practice of inserting leap seconds would cease after a specific date. Should the Earth's rotation continue to de-accelerate at its historical rate, the next discontinuity in UTC would be an hour inserted several centuries from now. Advocates of this proposal cite the need to synchronize satellite and other systems, such as GPS, Galileo, and GLONASS, which did not exist and were not envisioned when the current system was adopted. They note that leap second insertions can be and have been incorrectly implemented or accounted for. Such errors have to date had localized impact, but they could cause serious mishaps involving loss of life. For example, some GPS receivers have been known to fail simply because there was no leap second after a long enough interval, other GPS receivers failed because the leap second information was broadcast more than three months in advance, and some commercial software used for internet time-transfer Network Time Protocol (NTP) could either discard all data received after a leap second or interpret it as a frequency change. The ambiguity associated with the extra second could also disrupt financial accounting and certain forms of encryption. Those opposed to the proposal question the need for a change, and also point out the costs of adjusting to the proposed change and its inconvenience to amateur astronomers and others who rely upon astronomical calculations published in advance. Reports have been circulated that the cost of checking and correcting software to accommodate the new definition of UTC would be many millions of dollars for some systems. In October 2005 American Astronomical Society asked the ITU for a year's time to study the issue. This commission has

  19. Memory effect in M ≥ 6 earthquakes of South-North Seismic Belt, Mainland China

    Science.gov (United States)

    Wang, Jeen-Hwa

    2013-07-01

    The M ≥ 6 earthquakes occurred in the South-North Seismic Belt, Mainland China, during 1901-2008 are taken to study the possible existence of memory effect in large earthquakes. The fluctuation analysis technique is applied to analyze the sequences of earthquake magnitude and inter-event time represented in the natural time domain. Calculated results show that the exponents of scaling law of fluctuation versus window length are less than 0.5 for the sequences of earthquake magnitude and inter-event time. The migration of earthquakes in study is taken to discuss the possible correlation between events. The phase portraits of two sequent magnitudes and two sequent inter-event times are also applied to explore if large (or small) earthquakes are followed by large (or small) events. Together with all kinds of given information, we conclude that the earthquakes in study is short-term correlated and thus the short-term memory effect would be operative.

  20. Falling out of time

    DEFF Research Database (Denmark)

    Oldrup, Helene

    2017-01-01

    Using a temporal lens, the article shows how fathers’ incarceration leads to a loss of attunement to the temporal rhythms of their children's everyday lives. This lack of synchrony has implications for both the being and the becoming of the child. Through in-depth interviews, the article draws...... on data from a Danish study of mothers and children, aged 5–27, whose father/stepfather was incarcerated. Findings show the significance of a multifaceted understanding of time showing the implications of fathers’ imprisonment for children, suggesting that policy initiatives would be enriched by a focus...

  1. Multichannel time selector

    International Nuclear Information System (INIS)

    Momcilovic, M.; Jovanovic, S.

    1961-01-01

    Selector described is designed for spectrograph y of slow neutrons based on measuring the narration time-of flight along a certain trajectory. The analyser has 10 channels with variable widths from 5 - 640 μsec. detector unit contains a decadron counter for each channel as well as a mechanical counter to enable detection of one pulse per channel. Five channels are reserved for detecting background radiation twice as wide as the measuring channel. Neutron beam from the reactor is released or interrupted by a chopper. The angular speed of the chopper is from 200 - 1200 rotations/min. The instrument was designed in the Electronics Laboratory if the Boris Kidric Institute

  2. Time and Thermodynamics

    CERN Document Server

    Kirkland, Kyle

    2007-01-01

    Temperature is vital to the health and welfare of all living beings, and Earth's temperature varies considerably from place to place. Early humans could only live in warm areas such as the tropics. Although modern humans have the technology to keep their houses and offices warm even in cold environments, the growth and development of civilization has created unintentional effects. Cities are warmer than their surrounding regions, and on a global scale, Earth is experiencing rising temperatures. Thus, the science of thermodynamics offers an important tool to study these effects. "Time and

  3. Timing of Seasonal Sales.

    OpenAIRE

    Courty, Pascal; Li, Hao

    1999-01-01

    We present a model of timing of seasonal sales where stores choose several designs at the beginning of the season without knowing wich one, if any, will be fashionable. Fashionable designs have a chance to fetch high prices in fashion markets while non-fashionable ones must be sold in a discount market. In the beginning of the season, stores charge high prices in the hope of capturing their fashion market. As the end of the season approaches with goods still on the shelves, stores adjust down...

  4. Knowledge and time

    CERN Document Server

    2017-01-01

    This is a unique volume by a unique scientist, which combines conceptual, formal, and engineering approaches in a way that is rarely seen. Its core is the relation between ways of learning and knowing on the one hand and different modes of time on the other. Partial Boolean logic and the associated notion of complementarity are used to express this relation, and mathematical tools of fundamental physics are used to formalize it. Along the way many central philosophical problems are touched and addressed, above all the mind-body problem. Completed only shortly before the death of the author, the text has been edited and annotated by the author's close collaborator Harald Atmanspacher.

  5. Real Time Text Analysis

    Science.gov (United States)

    Senthilkumar, K.; Ruchika Mehra Vijayan, E.

    2017-11-01

    This paper aims to illustrate real time analysis of large scale data. For practical implementation we are performing sentiment analysis on live Twitter feeds for each individual tweet. To analyze sentiments we will train our data model on sentiWordNet, a polarity assigned wordNet sample by Princeton University. Our main objective will be to efficiency analyze large scale data on the fly using distributed computation. Apache Spark and Apache Hadoop eco system is used as distributed computation platform with Java as development language

  6. Time to experiment…

    Directory of Open Access Journals (Sweden)

    Gráinne Conole

    2002-12-01

    Full Text Available In the last edition of ALT-J, the editorial team decided to try an experiment by creating a more interactive and critical debate on a particular article with the journal. Readers were invited to submit comments on an article by Davis and Denning entitled: 'Almost as helpful as good theory: some conceptual possibilities for the online classroom' (Davis and Denning, 2000. Summarized below are some of the key comments raised about the paper. Many thanks to everyone who took the time to send in these comments; individual acknowledgements have not been included for reasons of confidentiality.

  7. Real time Faraday spectrometer

    Science.gov (United States)

    Smith, Jr., Tommy E.; Struve, Kenneth W.; Colella, Nicholas J.

    1991-01-01

    This invention uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements.

  8. Real time Faraday spectrometer

    International Nuclear Information System (INIS)

    Smith, T.E.; Struve, K.W.; Colella, N.J.

    1991-01-01

    This patent describes an invention which uses a dipole magnet to bend the path of a charged particle beam. As the deflected particles exit the magnet, they are spatially dispersed in the bend-plane of the magnet according to their respective momenta and pass to a plurality of chambers having Faraday probes positioned therein. Both the current and energy distribution of the particles is then determined by the non-intersecting Faraday probes located along the chambers. The Faraday probes are magnetically isolated from each other by thin metal walls of the chambers, effectively providing real time current-versus-energy particle measurements

  9. Timing divided attention.

    Science.gov (United States)

    Hogendoorn, Hinze; Carlson, Thomas A; VanRullen, Rufin; Verstraten, Frans A J

    2010-11-01

    Visual attention can be divided over multiple objects or locations. However, there is no single theoretical framework within which the effects of dividing attention can be interpreted. In order to develop such a model, here we manipulated the stage of visual processing at which attention was divided, while simultaneously probing the costs of dividing attention on two dimensions. We show that dividing attention incurs dissociable time and precision costs, which depend on whether attention is divided during monitoring or during access. Dividing attention during monitoring resulted in progressively delayed access to attended locations as additional locations were monitored, as well as a one-off precision cost. When dividing attention during access, time costs were systematically lower at one of the accessed locations than at the other, indicating that divided attention during access, in fact, involves rapid sequential allocation of undivided attention. We propose a model in which divided attention is understood as the simultaneous parallel preparation and subsequent sequential execution of multiple shifts of undivided attention. This interpretation has the potential to bring together diverse findings from both the divided-attention and saccade preparation literature and provides a framework within which to integrate the broad spectrum of divided-attention methodologies.

  10. The Sun in Time

    Science.gov (United States)

    Adams, Mitzi L.; Bero, Elizabeth; Sever, Thomas L.

    1999-01-01

    Leveraging funds from NASA's Initiative to Develop Education through Astronomy and Space Science (IDEAS) program, we combined the expertise of an archaeoastronomer, a solar scientist, and a teacher to trace humankind's view of the Sun and how that has changed, from the time of Stonehenge in about 1800 B.C.E., to the time of the Maya in 700 C.E., up to the modem era. Our program was aimed at middle-school students in an attempt to explain not only how science is done today, but how science has evolved from the observations of ancient societies. From these varied cultures, we touched on methods of observing the Sun, ideas of the composition of the Sun, and the relationship of the Sun to everyday life. Further, using the von Braun Astronomical Society's Planetarium in Huntsville, Alabama as a test-bed for the program, we illustrated concepts such as solstices, equinoxes, and local noon with approximately 800 eighth grade students from the local area. Our presentation to SEPA will include a description of NASA's IDEAS program and how to go about partnering with a NASA astronomer, some slides from our planetarium program and web-site, and some hands-on activities.

  11. Protophysics of time

    International Nuclear Information System (INIS)

    Janich, P.

    1985-01-01

    Protophysics stands for the program of a normative operational foundation of physics. Any scientific experience in physics hinges on the use of instruments, the relevant properties of which cannot be exhaustively defined. Therefore, a system of norms containing the purposes of measurement, as well as instructions on how to fulfil these norms in the production of measuring tools, defines basic physical magnitudes. This book is devoted to time measurement. It represents a substantial improvement relative to analytical and empiristic approaches to the same subject and provides, on the one hand, an avenue for the critical discussion of the presuppositions of relativistic physics. On the other hand, it represents a modern fulfilment of the Kantian a priori, namely the condition of the possibility of experience in physics. The work also contains a critical history of time measurement and of related philosophical theories. Audience: The book is of interest to philosophers, philosophers of science, physicists, historians of science, and historians of philosophy. It is suitable for textbook use and supplementary reading in courses on the general philosophy of science, and in special introductory courses to the philosophy of physics. (orig.)

  12. Time-dose modifications

    International Nuclear Information System (INIS)

    Kian Ang, K.

    1987-01-01

    Changes in fractionation schedule can be made by various approaches. However, from the first principle, it is anticipated that strategies of hyperfractionation and/or accelerated fractionation offer the most promised in improving the therapeutic ratio. Hyperfractionation is defined as a treatment schedule in which a large number of significantly reduced dose fractions (--1.2 Gy/fraction) is used to give a greater total dose in a conventional overall time period. The results of the pilot studies testing the efficacy of hyperfractionation have been encouraging. The most valid clinical trial of pure hyperfractionation, however, is that conducted by the EORTC. This study compared 70 Gy in 35 fractions or 80.5 Gy in 70 fractions over 7 weeks in the treatment of patients with oropharyngeal carcinomas. The local tumor control was significantly improved in the hyperfractionated arm without increasing the morbidity. Accelerated fractionation is defined as a schedule in which the overall time of treatment is reduced without significant changes in the total dose and fraction size. The strategy has been used to treat patients with malignant gliomas, melanomas and Head and Neck cancers. The data in Head and Neck Cancers seem to be promising

  13. Moments in time

    Directory of Open Access Journals (Sweden)

    Marc eWittmann

    2011-10-01

    Full Text Available It has been suggested that perception and action can be understood as evolving in temporal epochs or sequential processing units. Successive events are fused into units forming a unitary experience or ‘psychological present’. Studies have identified several temporal integration levels on different time scales which are fundamental for our understanding of behaviour and subjective experience. In recent literature concerning the philosophy and neuroscience of consciousness these separate temporal processing levels are not always precisely distinguished. Therefore, empirical evidence from psychophysics and neuropsychology on these distinct temporal processing levels is presented and discussed within philosophical conceptualizations of time experience. On an elementary level, one can identify a functional moment, a basic temporal building block of perception in the range of milliseconds that defines simultaneity and succession. Below a certain threshold temporal order is not perceived, individual events are processed as co-temporal. On a second level, an experienced moment, which is based on temporal integration of up to a few seconds, has been reported in many qualitatively different experiments in perception and action. It has been suggested that this segmental processing mechanism creates temporal windows that provide a logistical basis for conscious representation and the experience of nowness. On a third level of integration, continuity of experience is enabled by working-memory in the range of multiple seconds allowing the maintenance of cognitive operations and emotional feelings, leading to mental presence, a temporal window of an individual’s experienced presence.

  14. A time relay

    Energy Technology Data Exchange (ETDEWEB)

    Yosimura, K.; Sudzuki, Y.

    1981-06-18

    The synchronous micromotor of the time relay by means of a two staged cylindrical gear drive drives the gear wheel and the shaft of an actuating mechanism. The shaped drum of a cam mechanism, equipped with a vertical groove, which interacts in its upper part with a lever for driving the first commutating subassembly and in the lower, with a bent sector of a spring and plate movable contact of the second commutating subassembly, is attached to the lower end of the mechanism's shaft (V). The L-shaped lever of the second commutating subassembly's drive rests on a vertical rocking axle, located parallel to the shaft. Both pairs of spring and plate contacts are bracketed in two dielectric brackets which provide for a plane parallel disposition of the cited contacts. The operational time setting for the unit is a function of the initial angular position of the shaft, which is provided for by the attachment of a handle on its upper end.

  15. Prime time sexual harassment.

    Science.gov (United States)

    Grauerholz, E; King, A

    1997-04-01

    This study explores the explicit and implicit messages of sexual harassment that viewers receive when viewing prime-time television in the US. A content analysis of 48 hours of prime-time television reveals that sexual harassment on television is both highly visible and invisible. Sexual harassment is rendered visible simply by its prominence in these programs. Incidents involving quid-pro-quo harassment and environmental harassment occur with regularity on television. Furthermore, about 84% of the shows studied contained at least one incident of sexual harassment; yet these acts of sexual harassment remained largely invisible because none of the behaviors were labeled as sexual harassment. These incidents are presented in humorous ways, and victims are generally unharmed and very effective at ending the harassment. Although such programs may actually reflect the reality of many women's lives in terms of prevalence of sexual harassment, they perpetuate several myths about sexual harassment, such as that sexual harassment is not serious and that victims should be able to handle the situations themselves.

  16. Time-Delay Interferometry

    Directory of Open Access Journals (Sweden)

    Massimo Tinto

    2014-08-01

    Full Text Available Equal-arm detectors of gravitational radiation allow phase measurements many orders of magnitude below the intrinsic phase stability of the laser injecting light into their arms. This is because the noise in the laser light is common to both arms, experiencing exactly the same delay, and thus cancels when it is differenced at the photo detector. In this situation, much lower level secondary noises then set the overall performance. If, however, the two arms have different lengths (as will necessarily be the case with space-borne interferometers, the laser noise experiences different delays in the two arms and will hence not directly cancel at the detector. In order to solve this problem, a technique involving heterodyne interferometry with unequal arm lengths and independent phase-difference readouts has been proposed. It relies on properly time-shifting and linearly combining independent Doppler measurements, and for this reason it has been called time-delay interferometry (TDI. This article provides an overview of the theory, mathematical foundations, and experimental aspects associated with the implementation of TDI. Although emphasis on the application of TDI to the Laser Interferometer Space Antenna (LISA mission appears throughout this article, TDI can be incorporated into the design of any future space-based mission aiming to search for gravitational waves via interferometric measurements. We have purposely left out all theoretical aspects that data analysts will need to account for when analyzing the TDI data combinations.

  17. Timing of cyber conflict.

    Science.gov (United States)

    Axelrod, Robert; Iliev, Rumen

    2014-01-28

    Nations are accumulating cyber resources in the form of stockpiles of zero-day exploits as well as other novel methods of engaging in future cyber conflict against selected targets. This paper analyzes the optimal timing for the use of such cyber resources. A simple mathematical model is offered to clarify how the timing of such a choice can depend on the stakes involved in the present situation, as well as the characteristics of the resource for exploitation. The model deals with the question of when the resource should be used given that its use today may well prevent it from being available for use later. The analysis provides concepts, theory, applications, and distinctions to promote the understanding strategy aspects of cyber conflict. Case studies include the Stuxnet attack on Iran's nuclear program, the Iranian cyber attack on the energy firm Saudi Aramco, the persistent cyber espionage carried out by the Chinese military, and an analogous case of economic coercion by China in a dispute with Japan. The effects of the rapidly expanding market for zero-day exploits are also analyzed. The goal of the paper is to promote the understanding of this domain of cyber conflict to mitigate the harm it can do, and harness the capabilities it can provide.

  18. Copies, Concepts and Time

    Directory of Open Access Journals (Sweden)

    Anne Eriksen

    2017-09-01

    Full Text Available Copies are defined by their relation to an original. The understanding and evaluation of this relationship has been changing over time. A main argument of this article is that originals and copies are phenomena with no "natural" or essential meaning outside of their specific historical settings. The idea to be explored is how changing historicity regimes have transformed notions of originals and copies over time and how these differences also are reflected in the intrinsically temporal relation between the two concepts. The discussion will be framed by two theory sets. The first is Alexander Nagel and Christopher Woods investigation of two kinds of temporality that vied for dominance in works of art in the late Middle Ages and the Renaissance. The second is Walter Benjamins discussion of artwork in the "age of mechanical reproduction", i.e. the twentieth century. The second half of the article seeks to add to the historical complexity described by both theory sets by introducing a concept of tradition and discussing the early modern ideals of exemplarity, emulation and copiousness.

  19. The little book of time

    CERN Document Server

    Mainzer, Klaus

    2002-01-01

    chapter 1 Time in the Classical and Medieval Worldviews From the Beginnings to the Pre-Socratic School Zeno's Time Arrow and Aristotle's Continuum 6 Time and Creation According to Saint Augustine 15 Time and Medieval Astronomy 18 20 Calendars and Clocks chapter 2 Time in the Worldview of Classical Physics 25 Absolute Time According to Newton 26 Relational Time According to Leibniz 30 Time in Classical Mechanics 31 Time in Kant's Epistemology 35 chapter 3 Relativistic Spacetime 43 Time in Special Relativity Theory 44 Time in General Relativity Theory 50 Time in Relativistic Cosmology 54 chapter 4 Time and the Quantum World 61 Time in Quantum Mechanics 62 Time in Quantum Field Theories 70 Time, Black Holes, and the Anthropic Principle 78 Time and Thermodynamics chapter 5 83 Time in Equilibrium Thermodynamics 84 Time in Nonequilibrium Thermodynamics 2 9 Time, Irreversibility, and Self-Organization 100 chapter 6 Time and Life 107 Time in Darwin's Theory of Evolution 108 Time in Molecular Evolution 111 Time Hierar...

  20. Learning Time and Educational Effectiveness.

    Science.gov (United States)

    Anderson, Lorin W.

    1980-01-01

    To explore the relationship between time and school learning, this paper defines the three kinds of learning time identified by researchers--allocated time, time-on-task, and academic learning time--and relates them to curriculum development. The author cites evidence that time-on-task is related to student achievement and describes two…

  1. Timing is everything :

    Energy Technology Data Exchange (ETDEWEB)

    Kobos, Peter Holmes; Walker, La Tonya Nicole; Malczynski, Leonard A.

    2013-10-01

    People save for retirement throughout their career because it is virtually impossible to save all youll need in retirement the year before you retire. Similarly, without installing incremental amounts of clean fossil, renewable or transformative energy technologies throughout the coming decades, a radical and immediate change will be near impossible the year before a policy goal is set to be in place. Therefore, our research question is, To meet our desired technical and policy goals, what are the factors that affect the rate we must install technology to achieve these goals in the coming decades? Existing models do not include full regulatory constraints due to their often complex, and inflexible approaches to solve for optimal engineering instead of robust and multidisciplinary solutions. This project outlines the theory and then develops an applied software tool to model the laboratory-to-market transition using the traditional technology readiness level (TRL) framework, but develops subsequent and a novel regulatory readiness level (RRL) and market readiness level (MRL). This tool uses the ideally-suited system dynamics framework to incorporate feedbacks and time delays. Future energy-economic-environment models, regardless of their programming platform, may adapt this software model component framework or module to further vet the likelihood of new or innovative technology moving through the laboratory, regulatory and market space. The prototype analytical framework and tool, called the Technology, Regulatory and Market Readiness Level simulation model (TRMsim) illustrates the interaction between technology research, application, policy and market dynamics as they relate to a new or innovative technology moving from the theoretical stage to full market deployment. The initial results that illustrate the models capabilities indicate for a hypothetical technology, that increasing the

  2. High Time Resolution Astrophysics

    CERN Document Server

    Phelan, Don; Shearer, Andrew

    2008-01-01

    High Time Resolution Astrophysics (HTRA) is an important new window to the universe and a vital tool in understanding a range of phenomena from diverse objects and radiative processes. This importance is demonstrated in this volume with the description of a number of topics in astrophysics, including quantum optics, cataclysmic variables, pulsars, X-ray binaries and stellar pulsations to name a few. Underlining this science foundation, technological developments in both instrumentation and detectors are described. These instruments and detectors combined cover a wide range of timescales and can measure fluxes, spectra and polarisation. These advances make it possible for HTRA to make a big contribution to our understanding of the Universe in the next decade.

  3. Real time spectrum analysis

    International Nuclear Information System (INIS)

    Blunden, A.; O'Prey, D.G.; Tait, W.H.

    1983-01-01

    A method is described for the separation of a composite pulse-height spectrum into its unresolved component parts, which belong to a set of measured library spectra. The method allows real-time estimation giving running estimates during acquisition of the spectrum, minimises computation space, especially for a number of parallel calculations, estimates in advance the rms errors, and produces a significance measure for the hypothesis that the composite contains only the library spectra. Least squares curve-fitting, and other methods, can be compared, with the formalism developed, allowing analytical comparison of the effect of detector energy resolution and detection efficiency. A rational basis for the choice between the various methods of spectrum analysis follows from the theory, minimising rms estimation errors. The method described is applicable for very low numbers of counts and poor resolution. (orig.)

  4. Time dependent drift Hamiltonian

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1982-04-01

    The motion of individual charged particles in a given magnetic and an electric fields is discussed. An idea of a guiding center distribution function f is introduced. The guiding center distribution function is connected to the asymptotic Hamiltonian through the drift kinetic equation. The general non-stochastic magnetic field can be written in a contravariant and a covariant forms. The drift Hamiltonian is proposed, and the canonical gyroradius is presented. The proposed drift Hamiltonian agrees with Alfven's drift velocity to lowest non-vanishing order in the gyroradius. The relation between the exact, time dependent equations of motion and the guiding center equation is clarified by a Lagrangian analysis. The deduced Lagrangian represents the drift motion. (Kato, T.)

  5. Learning During Stressful Times

    Science.gov (United States)

    Shors, Tracey J.

    2012-01-01

    Stressful life events can have profound effects on our cognitive and motor abilities, from those that could be construed as adaptive to those not so. In this review, I discuss the general notion that acute stressful experience necessarily impairs our abilities to learn and remember. The effects of stress on operant conditioning, that is, learned helplessness, as well as those on classical conditioning procedures are discussed in the context of performance and adaptation. Studies indicating sex differences in learning during stressful times are discussed, as are those attributing different responses to the existence of multiple memory systems and nonlinear relationships. The intent of this review is to highlight the apparent plasticity of the stress response, how it might have evolved to affect both performance and learning processes, and the potential problems with interpreting stress effects on learning as either good or bad. An appreciation for its plasticity may provide new avenues for investigating its underlying neuronal mechanisms. PMID:15054128

  6. Ideologies of Time

    DEFF Research Database (Denmark)

    Berg Johansen, Christina; De Cock, Christian

    2018-01-01

    Our article deals with how elite corporate actors in a Western capitalist-democratic society conceive of and prepare for the future. Paying attention to how senior officers of 10 important Danish companies make sense of the future will help us to identify how particular temporal narratives...... their organization’s future and make plans for organizational action in a space where ‘business as usual’ reigns, and there is little engagement with the future as fundamentally open – as a time-yet-to-come. In using a conceptual lens inspired by the work of Fredric Jameson, we first explore the details...... of this presentism and a particular colonization of the future and then linger over small disruptions in the narratives of our interviewees which point to what escapes or jars their common sense frame, explore the implicit meanings they assign to their agency and also find clues and traces of temporal actions...

  7. BITOR's bad timing

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

    The setbacks suffered on two fronts recently by BITOR, which extracts and manufactures Orimulsion for Venezuela's state owned oil and gas company PDVSA, are discussed. The first is rejection of Orimulsion on environmental grounds by the respective governments for power generation plants in Florida and the United Kingdom. Both were perceived as showcase plants demonstrating the benefits of Orimulsion for the US and European markets. Secondly, BITOR, has been unfortunate in the timing of its promotion of Orimulsion which coincided with the 'dash for gas' in Europe and the start of the economic collapse in Asia. BITOR is now planning to buy foreign utilities to secure outlets for its product. Experience over the past decade suggests, however, that the promotion of Orimulsion is likely to be confined to those countries which have few indigenous energy resources and are therefore more likely to welcome a foreign fuel. (UK)

  8. Time, rate, and conditioning.

    Science.gov (United States)

    Gallistel, C R; Gibbon, J

    2000-04-01

    The authors draw together and develop previous timing models for a broad range of conditioning phenomena to reveal their common conceptual foundations: First, conditioning depends on the learning of the temporal intervals between events and the reciprocals of these intervals, the rates of event occurrence. Second, remembered intervals and rates translate into observed behavior through decision processes whose structure is adapted to noise in the decision variables. The noise and the uncertainties consequent on it have both subjective and objective origins. A third feature of these models is their timescale invariance, which the authors argue is a very important property evident in the available experimental data. This conceptual framework is similar to the psychophysical conceptual framework in which contemporary models of sensory processing are rooted. The authors contrast it with the associative conceptual framework.

  9. Technology Time Machine 2012

    DEFF Research Database (Denmark)

    Lehner, Wolfgang; Fettweis, Gerhard; Fitzek, Frank

    2013-01-01

    The IEEE Technology Time Machine (TTM) is a unique event for industry leaders, academics, and decision making government officials who direct R&D activities, plan research programs or manage portfolios of research activities. This report covers the main topics of the 2nd Symposium of future...... technologies. The Symposium brought together world renowned experts to discuss the evolutionary and revolutionary advances in technology landscapes as we look towards 2020 and beyond. TTM facilitated informal discussions among the participants and speakers thus providing an excellent opportunity for informal...... interaction between attendees, senior business leaders, world-renowned innovators, and the press. The goal of the Symposium is to discover key critical innovations across technologies which will alter the research and application space of the future. Topics covered the future of Wireless Technology, Smart...

  10. Cosmic time and chaos

    International Nuclear Information System (INIS)

    Heller, M.; Szydlowski, M.; Woszczyna, A.

    1986-01-01

    It is shown that the Friedman cosmological models with bulk viscosity dissipation, with Weyssenhoff fluid (perfect fluid with macroscopic spin), with a phase transition in a very early stage of the evolution, all possessing negative space-curvature, after being compactified, exhibit chaotic behaviour in asymptotic states. Geodesic flows in such models are characterized by an exponential instability; they are mixing ergodic and have non-zero metric entropy. In fact these world models are special cases of a ''chaotic evolution'' described by Lockhart, Misra and Prigogine. In particular, Prigogine's ''internal time'' may be defined in them. Some remarks, concerning a predictability in cosmological models with the geodesic instability, are made. 36 refs. (author)

  11. Changing times, similar challenges.

    Science.gov (United States)

    Baillie, Jonathan

    2013-11-01

    With IHEEM celebrating its 70th Anniversary this month, HEJ editor, Jonathan Baillie, recently met the Institute's oldest surviving Past-President, Lawrence Turner OBE, who, having in 1964 established a small engineering business producing some of the NHS's earliest nurse call systems from the basement of his three-storey West Midlands home, has since seen the company, Static Systems Group, grow to become one of the U.K. market-leaders in its field. The Institute's President from 1979-1981, he looked back, during a fascinating two-hour discussion, at his time in the role, talked through some of the key technological and other changes he has seen in the past five decades, reflected on an interesting and varied career, and considered some of the very different current-day challenges that today's IHEEM President, and the Institute as a whole, face.

  12. Non-Gaussian Autoregressive Processes with Tukey g-and-h Transformations

    KAUST Repository

    Yan, Yuan

    2017-11-20

    When performing a time series analysis of continuous data, for example from climate or environmental problems, the assumption that the process is Gaussian is often violated. Therefore, we introduce two non-Gaussian autoregressive time series models that are able to fit skewed and heavy-tailed time series data. Our two models are based on the Tukey g-and-h transformation. We discuss parameter estimation, order selection, and forecasting procedures for our models and examine their performances in a simulation study. We demonstrate the usefulness of our models by applying them to two sets of wind speed data.

  13. Non-Gaussian Autoregressive Processes with Tukey g-and-h Transformations

    KAUST Repository

    Yan, Yuan; Genton, Marc G.

    2017-01-01

    When performing a time series analysis of continuous data, for example from climate or environmental problems, the assumption that the process is Gaussian is often violated. Therefore, we introduce two non-Gaussian autoregressive time series models that are able to fit skewed and heavy-tailed time series data. Our two models are based on the Tukey g-and-h transformation. We discuss parameter estimation, order selection, and forecasting procedures for our models and examine their performances in a simulation study. We demonstrate the usefulness of our models by applying them to two sets of wind speed data.

  14. Implementing Run-Time Evaluation of Distributed Timing Constraints in a Real-Time Environment

    DEFF Research Database (Denmark)

    Kristensen, C. H.; Drejer, N.

    1994-01-01

    In this paper we describe a solution to the problem of implementing run-time evaluation of timing constraints in distributed real-time environments......In this paper we describe a solution to the problem of implementing run-time evaluation of timing constraints in distributed real-time environments...

  15. Free time, play and game

    OpenAIRE

    Božović Ratko R.

    2008-01-01

    Free time and play are mutually dependent categories that are always realized together. We either play because we have free time or we have free time because we play (E. Fink). Play, no matter whether it is children's or artistic play or a spontaneous sports game (excluding professional sports) most fully complements human existence and thereby realizes free time as a time in freedom and freedom of time. Therefore, free time exists and is most prominent in play. Moreover, one game releases it...

  16. Reorganising space and time:

    Directory of Open Access Journals (Sweden)

    Nicolas Senil

    2011-07-01

    Full Text Available The multiplication of objects, actors and underlying rationales of heritage development, or patrimonialisation, is increasingly blurring the strength and meaning of our relationship with the past. The aim of this article is to reflect on the processes involved in the emergence of new heritage objects and on the consequences of these developments. The article is based on a comparative analysis of two symmetric objects, both of which have been the subject of heritage development processes: the Chauvet cave and the Millau viaduct in Southern France. By showing that each object is projected in the spatial or temporal dimension from which it was a priori excluded at the time of its discovery, the analysis demonstrates the necessity of integrating a heritage approach to our understanding of territorial dynamics. The analysis suggests that the interplay of territorialisation and heritage development processes represents a reconstruction of a controlled time-space, a prerequisite for addressing a recurring problem in our society, that of its sustainability.La multiplication des objets, des acteurs et des logiques de la patrimonialisation génère un brouillage de plus en plus important sur la force et le sens de nos rapports au passé. Dans ce contexte, cet article se propose de réfléchir aux processus d’émergence de nouveaux objets patrimoniaux et aux conséquences de ces mobilisations. Il s’appuie sur l’analyse comparée de deux objets symétriques et tous deux patrimonialisés : la grotte Chauvet et le viaduc de Millau. En montrant que chaque objet est projeté dans la dimension spatiale ou temporelle dont il se trouve a priori exclu lors de son invention, l’analyse rappelle la nécessité d’intégrer une approche patrimoniale à notre lecture des dynamiques territoriales. Elle propose alors l’idée que ces mouvements croisés représentent une reconstruction d’un espace-temps maitrisé, nécessaire pour répondre au probl

  17. Auroral electron time dispersion

    International Nuclear Information System (INIS)

    Kletzing, C.A.

    1989-01-01

    A sounding rocket flight was launched from Greenland in 1985 to study high latitude, early morning auroral physics. The payload was instrumented with electron and ion detectors, AC and DC electric field experiments, a plasma density experiment, and a magnetometer to measure the ambient field. The rocket was launched during disturbed conditions, when the polar cap was in a contracted state with visible aurora overhead. The electron data contained numerous signatures indicative of time-of-flight energy dispersion characterized by a coherent structure in which lower energy electrons arrived at the rocket after higher energy electrons. A model was constructed to explain this phenomena by the sudden application of a region of parallel electric field along a length of magnetic field line above the rocket. The model incorporates detector response and uses an altitudinal density profile based on auroral zone measurements. Three types of potential structures were tried: linear, quadratic and cubic. Of the three it was found that the cubic (electric field growing in a quadratic manner moving up the field line) produced the best fit to the data. The potential region was found to be approximately 1-2 R e in extent with the lower edge 3000-4000 km away from the rocket. The background electron temperature in the model which produced the best fit to the data was of the order of 15 eV

  18. Time, Quantum and Information

    Energy Technology Data Exchange (ETDEWEB)

    Turner, Leaf [Los Alamos, New Mexico (United States)

    2004-04-09

    Time, Quantum and Information, a paean to Professor Carl Friedrich von Weizsaecker, commemorates his 90th birthday. The range of Professor Weizsaecker's endeavours is an exhilarating example of what can be accomplished by one freely-soaring human spirit, who is at the same time a physicist, a philosopher, and a humanitarian. The editors, Lutz Castell and Otfried Ischebeck, have assembled an admirable collection of essays and articles written by Weizsaecker?s past students, collaborators, colleagues and acquaintances. Time, Quantum and Information offers the reader a panoply of unique insights into twentieth century science and history. Entangled with the stories about Weizsaecker?s influence on the lives of some of the contributors are discussions of the activities of German scientists during and following World War II, emphasizing their reluctance to work on atomic weapons following the war. By outlining Weizsaecker?s role in the early development of numerous tributaries of physical science, the book gives us a new glimpse into the origins of some of its disparate domains, such as nuclear physics, the physics of stellar nucleosynthesis, cosmic ray physics, fluid turbulence, and the formation of the solar system. We physicists have all studied Weizsaecker?s semi-empirical mass formula describing the binding energy of nuclei. We are aware too that both he and Hans Bethe independently discovered the nuclear cycles that provide stars with their enduring energy output. We have studied the Weizsaecker--Williams technique of calculating the bremsstrahlung of relativistic electrons. But how many of us know of Weizsaecker's work in fluid turbulence that he, like Werner Heisenberg under whom he had earned his doctorate, pursued while holed up in Farm Hall? And how many of us are aware of his introduction of turbulent viscosity to account for the origin of planetary orbits, involving the migration of mass inwards and angular momentum outwards? Moreover, before

  19. The time slice system

    International Nuclear Information System (INIS)

    DeWitt, J.

    1990-01-01

    We have designed a fast readout system for silicon microstrip detectors which could be used at HERA, LHC, and SSC. The system consists of an analog amplifier-comparator chip (AACC) and a digital time slice chip (DTSC). The analog ship is designed in dielectric isolated bipolar technology for low noise and potential radiation hardness. The DTSC is built in CMOS for low power use and high circuit density. The main implementation aims are low power consumption and compactness. The architectural goal is automatic data reduction, and ease of external interface. The pipelining of event information is done digitally in the DTSC. It has a 64 word deep level 1 buffer acting as a FIFO, and a 16 word deep level 2 buffer acting as a dequeue. The DTSC also includes an asynchronous bus interface. We are first building a scaled up (100 μm instead of 25 μm pitch) and slower (10 MHz instead of 60 MHz) version in 2 μm CMOS and plan to test the principle of operation of this system in the Leading Proton Spectrometer (LPS) of the ZEUS detector at HERA. Another very important development will be tested there: the radiation hardening of the chips. We have started a collaboration with a rad-hard foundry and with Los Alamos National Laboratories to test and evaluate rad-hard processes and the final rad-hard product. Initial data are very promising, because radiation resistance of up to many Mrad have been achieved. (orig.)

  20. Roe in Turbulent Time

    Directory of Open Access Journals (Sweden)

    Patrizia Gazzola

    2014-01-01

    Full Text Available The aim of the paper is to compare the utility of the net income (NI and of the comprehensive income for the evaluation of financial performance of the company and to verify whether the total comprehensive income (TCI is more value relevant than the net income especially in times of crisis (IAS 1, par. 5.The Financial Accounting Standards Board (FASB has continued to emphasize a financial measure called other comprehensive income (OCI as a valuable financial analysis tool. The FASB’s goal is to issue guidance to improve the comparability, the consistency and the transparency of financial reporting. Especially in the period of financial crises, OCI measure is also quite helpful to understand the company’s situation. The methodology in the elaboration of this article comes from the author’s previous research, which formed the main part of the overall research. The new research was based on the previous one but we have increased the number of financial statements analyzed by including companies of the free market for the year 2011. In the last part of the paper we show the results of empirical research on the income statement of the Czech companies, which adopted IAS/IFRS principles.

  1. Time, Quantum and Information

    International Nuclear Information System (INIS)

    Turner, Leaf

    2004-01-01

    Time, Quantum and Information, a paean to Professor Carl Friedrich von Weizsaecker, commemorates his 90th birthday. The range of Professor Weizsaecker's endeavours is an exhilarating example of what can be accomplished by one freely-soaring human spirit, who is at the same time a physicist, a philosopher, and a humanitarian. The editors, Lutz Castell and Otfried Ischebeck, have assembled an admirable collection of essays and articles written by Weizsaecker?s past students, collaborators, colleagues and acquaintances. Time, Quantum and Information offers the reader a panoply of unique insights into twentieth century science and history. Entangled with the stories about Weizsaecker?s influence on the lives of some of the contributors are discussions of the activities of German scientists during and following World War II, emphasizing their reluctance to work on atomic weapons following the war. By outlining Weizsaecker?s role in the early development of numerous tributaries of physical science, the book gives us a new glimpse into the origins of some of its disparate domains, such as nuclear physics, the physics of stellar nucleosynthesis, cosmic ray physics, fluid turbulence, and the formation of the solar system. We physicists have all studied Weizsaecker?s semi-empirical mass formula describing the binding energy of nuclei. We are aware too that both he and Hans Bethe independently discovered the nuclear cycles that provide stars with their enduring energy output. We have studied the Weizsaecker--Williams technique of calculating the bremsstrahlung of relativistic electrons. But how many of us know of Weizsaecker's work in fluid turbulence that he, like Werner Heisenberg under whom he had earned his doctorate, pursued while holed up in Farm Hall? And how many of us are aware of his introduction of turbulent viscosity to account for the origin of planetary orbits, involving the migration of mass inwards and angular momentum outwards? Moreover, before finally

  2. Time-independent wormholes

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Zicao; Marolf, Donald; Mefford, Eric [Department of Physics, University of California,Santa Barbara, CA 93106 (United States)

    2016-12-06

    We study two-sided static wormholes with an exact Killing symmetry that translates both mouths of the wormhole toward the future. This differs from the familiar Kruskal wormhole whose time translation is future-directed only in one asymptotic region and is instead past-directed in the other. Our spacetimes are solutions to Einstein-Hilbert gravity sourced by scalar domain walls. Explicit examples are found in the thin wall approimation. More generally, we show that such spacetimes can arise in the presence of scalar fields with potentials that are C{sup 1} but not C{sup 2} and find examples numerically. However, solutions with an exact such Killing symmetry are forbidden when the scalar potential is smooth. Finally, we consider the mutual information of boundary regions associated with such wormholes in AdS/CFT. Although the interior of our solutions are unstable, we find that even mutual informations between opposite boundaries are already thermalized at any finite t in the sense that they agree with the t→∞ limit of results from the familiar AdS-Kruskal solution.

  3. The law of times

    International Nuclear Information System (INIS)

    Knizia, K.

    1986-01-01

    The implicit confidence in technology of former decades has long since given way to an equally doubtful hostility towards technology. Criticism is focusing on energy economy and the 'hard technologies' it advocates. The publication for the first time gives public access to a number of papers and essays discussing this criticism in a most detailed and competent way. Based on different aspects and theories maintained by natural science, philosophy, ethics and world economy the author concludes that it is not cuts but a consistent technological extension leading to long-term living conditions worthy of a human being and to the benefit of the major part of the population. The publication deals with the following subjects: pros and cons of a nuclear phaseout; technology as a prior condition of modern humanity, energy for our world; energy - order - humanity; responsibility and technology; engineers - mediators between energy technology and society, future energy supply and technological changes; innovation and the interaction between technology and science; energy supply and pollution abatement; nuclear technology and long-term energy supplies; from mechanics to energy technology - 200 years of German steam engineering; the implications of the second law of thermodynamics for human life; arguments in favour of a general energy system. (orig./HP) [de

  4. Time to gather stones…

    Directory of Open Access Journals (Sweden)

    Elena Lyudvigovna Yakovleva

    2015-03-01

    Full Text Available Objective to search for ways of further development of modern Russia affected by sanctions. Methods dialectical method of cognition of the solitude phenomenon metaphorically transferred from personality to the image of Russia phenomenological method establishing a positive diversity solitude states futurological forecasting method by which the Russia development trends are visualized. Results the situation of the Russian society which appeared in solitude is not a reason for pessimism. This is positive time for reflection on the situation and correcting the errors there is a possibility to recover the Russian identity to form the image of Motherland and inclusive existence based on the culture of partnership and solidarity. Scientific novelty the analysis of the solitude state allows to detect its positive potential associated with correction of errors restoration of the image of Motherland and formation of identity. So that their effectiveness had a lasting effect it is necessary to pay attention to the inclusive education system which brings up a personality included into existence. Practical value the main provisions and conclusions of the article can be used in scientific educational and practical activities in the review and analysis of the state of modern Russian society under sanctions. nbsp

  5. Christian reckoning of time

    Directory of Open Access Journals (Sweden)

    Ks. Tomasz Stempa

    2014-12-01

    Full Text Available The issue of the liturgical calendar of the Orthodox Church is one of the topics currently being discussed. Using thejulian or neojulian liturgical calendar raises in faithful not only dilemmas or doubts, but also confusion, as shown by discussionson some social networking sites.The author of this text wants to bring closer reader to the problems of this issue and clarify the liturgical and calendarduality. This paper also develops such topics as the history of the christian calendar, reckoning of years, creation of calendars:julian, gregorian and neojulian, as well as problems arising from using two calendars within one local Church.This work shows that the use of one kind or another calendar is not a violation of dogma, but may lead to a breach ofa rule, established at the time of the Ecumenical Councils. You should be aware that the julian calendar was not strictlya calendar set up for the liturgical aims, but it was adapted for formulating the liturgical order.Experience of the liturgical life shows that, even though type of calendar is not a dogma, entering neojulian calendarpermanently divided some local Orthodox communities. Introduction of neojulian calendar was not necessary, and theevents at the beginning of the twentieth century is warning to refrain from taking radical action to reform liturgical life.Certainly this is a difficult issue that requires common action under the providence of Grace of the Holy Spirit.

  6. Time Error Analysis of SOE System Using Network Time Protocol

    International Nuclear Information System (INIS)

    Keum, Jong Yong; Park, Geun Ok; Park, Heui Youn

    2005-01-01

    To find the accuracy of time in the fully digitalized SOE (Sequence of Events) system, we used a formal specification of the Network Time Protocol (NTP) Version 3, which is used to synchronize time keeping among a set of distributed computers. Through constructing a simple experimental environments and experimenting internet time synchronization, we analyzed the time errors of local clocks of SOE system synchronized with a time server via computer networks

  7. Timing organization of a real-time multicore processor

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Sparsø, Jens

    2017-01-01

    Real-time systems need a time-predictable computing platform. Computation, communication, and access to shared resources needs to be time-predictable. We use time division multiplexing to statically schedule all computation and communication resources, such as access to main memory or message...... passing over a network-on-chip. We use time-driven communication over an asynchronous network-on-chip to enable time division multiplexing even in a globally asynchronous, locally synchronous multicore architecture. Using time division multiplexing at all levels of the architecture yields in a time...

  8. Dense time discretization technique for verification of real time systems

    International Nuclear Information System (INIS)

    Makackas, Dalius; Miseviciene, Regina

    2016-01-01

    Verifying the real-time system there are two different models to control the time: discrete and dense time based models. This paper argues a novel verification technique, which calculates discrete time intervals from dense time in order to create all the system states that can be reached from the initial system state. The technique is designed for real-time systems specified by a piece-linear aggregate approach. Key words: real-time system, dense time, verification, model checking, piece-linear aggregate

  9. SLH Timing Belt Powertrain

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, Abe

    2014-04-09

    The main goal of this proposal was to develop and test a novel powertrain solution for the SLH hydroEngine, a low-cost, efficient low-head hydropower technology. Nearly two-thirds of U.S. renewable electricity is produced by hydropower (EIA 2010). According to the U.S. Department of Energy; this amount could be increased by 50% with small hydropower plants, often using already-existing dams (Hall 2004). There are more than 80,000 existing dams, and of these, less than 4% generate power (Blankinship 2009). In addition, there are over 800 irrigation districts in the U.S., many with multiple, non-power, low-head drops. These existing, non-power dams and irrigation drops could be retrofitted to produce distributed, baseload, renewable energy with appropriate technology. The problem is that most existing dams are low-head, or less than 30 feet in height (Ragon 2009). Only about 2% of the available low-head hydropower resource in the U.S. has been developed, leaving more than 70 GW of annual mean potential low-head capacity untapped (Hall 2004). Natel Energy, Inc. is developing a low-head hydropower turbine that operates efficiently at heads less than 6 meters and is cost-effective for deployment across multiple low-head structures. Because of the unique racetrack-like path taken by the prime-movers in the SLH, a flexible powertrain is required. Historically, the only viable technological solution was roller chain. Despite the having the ability to easily attach blades, roller chain is characterized by significant drawbacks, including high cost, wear, and vibration from chordal action. Advanced carbon- fiber-reinforced timing belts have been recently developed which, coupled with a novel belt attachment system developed by Natel Energy, result in a large reduction in moving parts, reduced mass and cost, and elimination of chordal action for increased fatigue life. The work done in this project affirmatively addressed each of the following 3 major uncertainties concerning

  10. Medulloblastoma: progress over time

    International Nuclear Information System (INIS)

    Smee, Robert I.; Williams, Janet R.; De-loyde, Katie J.; Meagher, Nicola S.; Cohn, Richard

    2012-01-01

    Medulloblastoma is the most common central nervous system tumour in children aged 0–4 years, with 75% of cases occurring in patients <16 years, and rare in adults. The intent of this audit is to review a single centre's experience and to compare outcomes with other centres' outcomes. This Ethics approved retrospective audit evaluates the paediatric population aged <16 years who received radiotherapy as their initial or salvage treatment at the Prince of Wales Hospital Cancer Centre between 1972 and 2007. The primary and secondary end-points were progression-free survival (PFS) and cancer-specific survival (CSS), with comparisons made between patients treated before and after 1990, and the impact of high- and low-risk disease. There were 80 eligible patients, 78 who had radiotherapy at initial presentation, and 2 at the time of recurrence. Median age was 6.5 years, 52 were boys and 28 were girls. Seventy-eight patients had a surgical procedure and ultimately received craniospinal radiotherapy. Of these 78 patients, 32 (40%) had a macroscopically complete resection. The 5-year PFS was 69.7%. The 5-year PFS for patients treated pre and post 1990 was 66.1% and 71.8%, respectively. The 5-year CSS for high- and low-risk patients was 61.1% and 78.4%, respectively. Ultimately, 33% of patients were dead due to disease. This audit demonstrates those children referred to this facility for treatment have comparable survival to that of other major centres.

  11. Time to talk condoms.

    Science.gov (United States)

    Piotrow, P T; Rinehart, W

    1991-09-01

    A great deal of avoided if political and religious leaders, educators, health care providers and the mass media would band together in an effort to promote condom use. Condoms use protects against unwanted pregnancies, STDs and AIDS. Yet, public discussions on condom use are rate. In the US, political leaders avoid mentioning the topic, and television networks severely restrict the airing of public service announcements for condoms. Worldwide, an estimated 100 billion acts of sexual intercourse take place every year. A recent report indicates that it would take a modest 13 billion condoms a year to protect everyone who is at risk of contracting AIDS and other STDs, and risk of having an unwanted pregnancy. Currently, worldwide production of condoms stands at about 6 billion a year. Furthermore, condom makers have the capacity to increase production by some 2 billion, and could add new capacity in about 2 years. Many believe that marketing condoms is a difficult enterprise, since men often report that condoms reduce pleasure, cause embarrassment, or are not available when needed. The challenge for markets, then, is to create demand. This is especially true in the US, where prime-time advertising and the use of popular entertainment, such as soap operas, could promote condoms as both safe and satisfying. In the developing world, the challenge is to make condoms widely available and affordable. Some changes have taken place since 1981, when AIDS first came into the spotlight. In the US, people now discuss the topic of STDs more openly. But an all-out effort to promote condom use has not yet begun.

  12. Management Styles and Techniques: Time.

    Science.gov (United States)

    Matthews, Priscilla J.

    1987-01-01

    Discusses strategies to improve individuals' use of time and personal satisfaction through time management. The 126-item bibliography includes citations for time management in general and special sections for career development, family and parenting, women, and home management. (CLB)

  13. Time functions function best as functions of multiple times

    NARCIS (Netherlands)

    Desain, P.; Honing, H.

    1992-01-01

    This article presents an elegant way of representing control functions at an abstractlevel. It introduces time functions that have multiple times as arguments. In this waythe generalized concept of a time function can support absolute and relative kinds of time behavior. Furthermore the

  14. Recapturing time: a practical approach to time management for physicians.

    Science.gov (United States)

    Gordon, Craig E; Borkan, Steven C

    2014-05-01

    Increasing pressures on physicians demand effective time management and jeopardise professional satisfaction. Effective time management potentially increases productivity, promotes advancement, limits burnout and improves both professional and personal satisfaction. However, strategies for improving time management are lacking in the current medical literature. Adapting time management techniques from the medical and non-medical literature may improve physician time management habits. These techniques can be divided into four categories: (1) setting short and long-term goals; (2) setting priorities among competing responsibilities; (3) planning and organising activities; and (4) minimising 'time wasters'. Efforts to improve time management can increase physician productivity and enhance career satisfaction.

  15. Fractional Diffusion Limit for Collisional Kinetic Equations

    KAUST Repository

    Mellet, Antoine

    2010-08-20

    This paper is devoted to diffusion limits of linear Boltzmann equations. When the equilibrium distribution function is a Maxwellian distribution, it is well known that for an appropriate time scale, the small mean free path limit gives rise to a diffusion equation. In this paper, we consider situations in which the equilibrium distribution function is a heavy-tailed distribution with infinite variance. We then show that for an appropriate time scale, the small mean free path limit gives rise to a fractional diffusion equation. © 2010 Springer-Verlag.

  16. Tuberculosis in ancient times

    Directory of Open Access Journals (Sweden)

    Louise Cilliers

    2008-09-01

    Full Text Available In spite of an array of effective antibiotics, tuberculosis is still very common in developing countries where overcrowding, malnutrition and poor hygienic conditions prevail. Over the past 30 years associated HIV infection has worsened the situation by increasing the infection rate and mortality of tuberculosis. Of those diseases caused by a single organism only HIV causes more deaths internationally than tuberculosis. The tubercle bacillus probably first infected man in Neolithic times, and then via infected cattle, but the causative Mycobacteriacea have been in existence for 300 million years. Droplet infection is the most common way of acquiring tuberculosis, although ingestion (e.g. of infected cows’ milk may occur. Tuberculosis probably originated in Africa. The earliest path gnomonic evidence of human tuberculosis in man was found in osteo-archaeological findings of bone tuberculosis (Pott’s disease of the spine in the skeleton of anEgyptian priest from the 21st Dynasty (approximately 1 000 BC. Suggestive but not conclusiveevidence of tuberculotic lesions had been found in even earlier skeletons from Egypt and Europe. Medical hieroglyphics from ancient Egypt are silent on the disease, which could be tuberculosis,as do early Indian and Chinese writings. The Old Testament refers to the disease schachapeth, translated as phthisis in the Greek Septuagint. Although the Bible is not specific about this condition, tuberculosis is still called schachapeth in modern Hebrew. In pre-Hippocratic Greece Homer did not mention phthisis, a word meaning non-specific wasting of the body. However. Alexander of Tralles (6th century BC seemed to narrow the concept down to a specific disease, and in the Hippocratic Corpus (5th-4th centuries BC phthisis can be recognised as tuberculosis. It was predominantly a respiratory disease commonly seen and considered to be caused by an imbalance of bodily humours. It was commonest in autumn, winter and spring

  17. EDITORIAL: Interesting times

    Science.gov (United States)

    Dobson Honorary Editor, Ken

    1996-01-01

    `May you live in interesting times' - old Chinese curse. First, many thanks to John Avison, the retiring Honorary Editor, for his hard work over the last five years, and the steady development in style and content under his stewardship. I can only hope to live up to the standards that he set. The next five years will take us into a new millenium, an event preceded - in England and Wales at least - by a period of stability, reflection and consolidation in education. Or so we are told - but whether such a self-denying ordinance will actually be maintained by the Government both before and after an election in 1997 remains to be seen. Nevertheless, we shall be thankful for any mercies, however small, that permit forward thinking rather than instant response. One of the things that readers of a journal called Physics Education should be thinking about is the continued decline in the numbers of students studying physics post-16. This is not a purely local phenomenon; most European countries are finding a similar decline. There are exceptions, of course: in Scotland numbers studying physics for Highers are increasing. Is such a decline a good thing or a bad thing? Only a minority of post-16 physics students go on to use the bulk of what they have learned in further studies or vocations. Does a knowledge and understanding of physics contribute to the mental well-being and cultural level - let alone material comfort - of any except those who use physics professionally? Is physics defensible as a contribution to the mental armoury of the educated citizen - compared with chemistry, biology - or Latin, say? Or should one rephrase that last question as `Is physics as we teach it today defensible...?' Such questions, and many others no doubt, may well be in the mind of the new Curriculum Officer appointed by the Institute of Physics `to engage in a wide-ranging consultation throughout the entire physics community on the nature and style of post-16 physics programmes, with a

  18. Time Optimal Run-time Evaluation of Distributed Timing Constraints in Process Control Software

    DEFF Research Database (Denmark)

    Drejer, N.; Kristensen, C.H.

    1993-01-01

    This paper considers run-time evaluation of an important class of constraints; Timing constraints. These appear extensively in process control systems. Timing constraints are considered in distributed systems, i.e. systems consisting of multiple autonomous nodes......

  19. Time averaging, ageing and delay analysis of financial time series

    Science.gov (United States)

    Cherstvy, Andrey G.; Vinod, Deepak; Aghion, Erez; Chechkin, Aleksei V.; Metzler, Ralf

    2017-06-01

    We introduce three strategies for the analysis of financial time series based on time averaged observables. These comprise the time averaged mean squared displacement (MSD) as well as the ageing and delay time methods for varying fractions of the financial time series. We explore these concepts via statistical analysis of historic time series for several Dow Jones Industrial indices for the period from the 1960s to 2015. Remarkably, we discover a simple universal law for the delay time averaged MSD. The observed features of the financial time series dynamics agree well with our analytical results for the time averaged measurables for geometric Brownian motion, underlying the famed Black-Scholes-Merton model. The concepts we promote here are shown to be useful for financial data analysis and enable one to unveil new universal features of stock market dynamics.

  20. Scheduling with target start times

    NARCIS (Netherlands)

    Hoogeveen, J.A.; Velde, van de S.L.; Klein Haneveld, W.K.; Vrieze, O.J.; Kallenberg, L.C.M.

    1997-01-01

    We address the single-machine problem of scheduling n independent jobs subject to target start times. Target start times are essentially release times that may be violated at a certain cost. The goal is to minimize an objective function that is composed of total completion time and maximum

  1. [Psychological time, definition and challenges].

    Science.gov (United States)

    Droit-Volet, Sylvie

    2012-10-01

    Psychological time comprises different forms of time. Each form of time corresponds to different psychological mechanisms. The human being is subject to distortions of time under the effect of emotions. The effectiveness of social interaction depends on our aptitude to synchronise ourselves with others.

  2. Time perception and time perspective differences between adolescents and adults.

    Science.gov (United States)

    Siu, Nicolson Y F; Lam, Heidi H Y; Le, Jacqueline J Y; Przepiorka, Aneta M

    2014-09-01

    The present experiment aimed to investigate the differences in time perception and time perspective between subjects representing two developmental stages, namely adolescence and middle adulthood. Twenty Chinese adolescents aged 15-25 and twenty Chinese adults aged 35-55 participated in the study. A time discrimination task and a time reproduction task were implemented to measure the accuracy of their time perception. The Zimbardo Time Perspective Inventory (Short-Form) was adopted to assess their time orientation. It was found that adolescents performed better than adults in both the time discrimination task and the time reproduction task. Adolescents were able to differentiate different time intervals with greater accuracy and reproduce the target duration more precisely. For the time reproduction task, it was also found that adults tended to overestimate the duration of the target stimuli while adolescents were more likely to underestimate it. As regards time perspective, adults were more future-oriented than adolescents, whereas adolescents were more present-oriented than adults. No significant relationship was found between time perspective and time perception. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Introducing time a graphic guide

    CERN Document Server

    Callender, Craig

    2010-01-01

    What is time? The 5th-century philosopher St Augustine famously said that he knew what time was, so long as no one asked him. Is time a fourth dimension similar to space or does it flow in some sense? And if it flows, does it make sense to say how fast? Does the future exist? Is time travel possible? Why does time seem to pass in only one direction?These questions and others are among the deepest and most subtle that one can ask, but "Introducing Time" presents them - many for the first time - in an easily accessible, lucid and engaging manner, wittily illustrated by Ralph Edney.

  4. Playing Games with Timed Games

    DEFF Research Database (Denmark)

    David, Alexandre; Larsen, Kim Guldstrand; Chatain, Thomas

    2009-01-01

    In this paper we focus on property-preserving preorders between timed game automata and their application to control of partially observable systems. Following the example of timed simulation between timed automata, we define timed alternating simulation as a preorder between timed game automata......, which preserves controllability. We define a method to reduce the timed alternating simulation problem to a safety game. We show how timed alternating simulation can be used to control efficiently a partially observable system. This method is illustrated by a generic case study....

  5. Timing properties of a time-of-flight detector

    International Nuclear Information System (INIS)

    Nakagawa, Takahide; Yuasa-Nakagawa, Keiko.

    1989-01-01

    The time resolution of a time-of-flight (T.O.F.) detector which consists of a channel plate detector (CPD) with a central hole and a surface barrier detector (SBD) was measured. A time resolution of 80 psec fwhm was obtained for 8.78 MeV alpha particles. The influence on fast timing of the SBD of alpha particles was carefully studied. The plasma delay time and time resolution of the SBD were found to strongly depend on the electric field strength and properties of the SBD. (author)

  6. Computer network time synchronization the network time protocol

    CERN Document Server

    Mills, David L

    2006-01-01

    What started with the sundial has, thus far, been refined to a level of precision based on atomic resonance: Time. Our obsession with time is evident in this continued scaling down to nanosecond resolution and beyond. But this obsession is not without warrant. Precision and time synchronization are critical in many applications, such as air traffic control and stock trading, and pose complex and important challenges in modern information networks.Penned by David L. Mills, the original developer of the Network Time Protocol (NTP), Computer Network Time Synchronization: The Network Time Protocol

  7. Perception, time of perception, perception of the time

    OpenAIRE

    Barata, André

    2009-01-01

    From a conceptual point of view, time is independent of its experience. That is: it can be given a conceptual description of time without any reference to terms related to the subjective consciousness of time. But concerning a phenomenology of that subjective experience of time, it can it be showed that such experience of time is, in itself, temporal. The very same terms employed in a conceptual description of time – terms like “change” and “duration”– are implied in the phenomenological desc...

  8. Timed arrays wideband and time varying antenna arrays

    CERN Document Server

    Haupt, Randy L

    2015-01-01

    Introduces timed arrays and design approaches to meet the new high performance standards The author concentrates on any aspect of an antenna array that must be viewed from a time perspective. The first chapters briefly introduce antenna arrays and explain the difference between phased and timed arrays. Since timed arrays are designed for realistic time-varying signals and scenarios, the book also reviews wideband signals, baseband and passband RF signals, polarization and signal bandwidth. Other topics covered include time domain, mutual coupling, wideband elements, and dispersion. The auth

  9. Beyond time management: time use, performance and well-being

    OpenAIRE

    Ilona BONIWELL; Evgeny OSIN

    2015-01-01

    In this review questions such as “What is a good use of time?”, “How can one achieve satisfaction with their time?” and “How can one’s relationship with time contribute to their well-being?” are raised and discussed with regard to empirical research on various aspects of positive psychology of time. This paper differs from traditional approach to thinking about time in organisations in three substantial ways. Firstly, it reviews the existing empirical research on time use, focusin...

  10. 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...

  11. Thinking aloud influences perceived time.

    Science.gov (United States)

    Hertzum, Morten; Holmegaard, Kristin Due

    2015-02-01

    We investigate whether thinking aloud influences perceived time. Thinking aloud is widely used in usability evaluation, yet it is debated whether thinking aloud influences thought and behavior. If thinking aloud is restricted to the verbalization of information to which a person is already attending, there is evidence that thinking aloud does not influence thought and behavior. In an experiment, 16 thinking-aloud participants and 16 control participants solved a code-breaking task 24 times each. Participants estimated task duration. The 24 trials involved two levels of time constraint (timed, untimed) and resulted in two levels of success (solved, unsolved). The ratio of perceived time to clock time was lower for thinking-aloud than control participants. Participants overestimated time by an average of 47% (thinking aloud) and 94% (control). The effect of thinking aloud on time perception also held separately for timed, untimed, solved, and unsolved trials. Thinking aloud (verbalization at Levels 1 and 2) influences perceived time. Possible explanations of this effect include that thinking aloud may require attention, cause a processing shift that overshadows the perception of time, or increase mental workload. For usability evaluation, this study implies that time estimates made while thinking aloud cannot be compared with time estimates made while not thinking aloud, that ratings of systems experienced while thinking aloud may be inaccurate (because the experience of time influences other experiences), and that it may therefore be considered to replace concurrent thinking aloud with retrospective thinking aloud when evaluations involve time estimation.

  12. A real-time architecture for time-aware agents.

    Science.gov (United States)

    Prouskas, Konstantinos-Vassileios; Pitt, Jeremy V

    2004-06-01

    This paper describes the specification and implementation of a new three-layer time-aware agent architecture. This architecture is designed for applications and environments where societies of humans and agents play equally active roles, but interact and operate in completely different time frames. The architecture consists of three layers: the April real-time run-time (ART) layer, the time aware layer (TAL), and the application agents layer (AAL). The ART layer forms the underlying real-time agent platform. An original online, real-time, dynamic priority-based scheduling algorithm is described for scheduling the computation time of agent processes, and it is shown that the algorithm's O(n) complexity and scalable performance are sufficient for application in real-time domains. The TAL layer forms an abstraction layer through which human and agent interactions are temporally unified, that is, handled in a common way irrespective of their temporal representation and scale. A novel O(n2) interaction scheduling algorithm is described for predicting and guaranteeing interactions' initiation and completion times. The time-aware predicting component of a workflow management system is also presented as an instance of the AAL layer. The described time-aware architecture addresses two key challenges in enabling agents to be effectively configured and applied in environments where humans and agents play equally active roles. It provides flexibility and adaptability in its real-time mechanisms while placing them under direct agent control, and it temporally unifies human and agent interactions.

  13. Timing intervals using population synchrony and spike timing dependent plasticity

    Directory of Open Access Journals (Sweden)

    Wei Xu

    2016-12-01

    Full Text Available We present a computational model by which ensembles of regularly spiking neurons can encode different time intervals through synchronous firing. We show that a neuron responding to a large population of convergent inputs has the potential to learn to produce an appropriately-timed output via spike-time dependent plasticity. We explain why temporal variability of this population synchrony increases with increasing time intervals. We also show that the scalar property of timing and its violation at short intervals can be explained by the spike-wise accumulation of jitter in the inter-spike intervals of timing neurons. We explore how the challenge of encoding longer time intervals can be overcome and conclude that this may involve a switch to a different population of neurons with lower firing rate, with the added effect of producing an earlier bias in response. Experimental data on human timing performance show features in agreement with the model’s output.

  14. The Cherenkov correlated timing detector: materials, geometry and timing constraints

    International Nuclear Information System (INIS)

    Aronstein, D.; Bergfeld, T.; Horton, D.; Palmer, M.; Selen, M.; Thayer, G.; Boyer, V.; Honscheid, K.; Kichimi, H.; Sugaya, Y.; Yamaguchi, H.; Yoshimura, Y.; Kanda, S.; Olsen, S.; Ueno, K.; Tamura, N.; Yoshimura, K.; Lu, C.; Marlow, D.; Mindas, C.; Prebys, E.; Pomianowski, P.

    1996-01-01

    The key parameters of Cherenkov correlated timing (CCT) detectors are discussed. Measurements of radiator geometry, optical properties of radiator and coupling materials, and photon detector timing performance are presented. (orig.)

  15. Picture Memory Improves with Longer On Time and Off Time

    Science.gov (United States)

    Tversky, Barbara; Sherman, Tracy

    1975-01-01

    Both recognition and recall of pictures improve as picture presentation time increases and as time between picture increases. This experiment was compared with an earlier one by Shaffer and Shiffrin (1972). (Editor/RK)

  16. Time coder for slow neutron time-of-flight spectrometer

    International Nuclear Information System (INIS)

    Grashilin, V.A.; Ofengenden, R.G.

    1988-01-01

    Time coder for slow neutron time-of-flight spectrometer is described. The time coder is of modular structure, is performed in the CAMAC standard and operates on line with DVK-2 computer. The main coder units include supporting generator, timers, time-to-digital converter, memory unit and crate controller. Method for measuring background symmetrically to the effect is proposed for a more correct background accounting. 4 refs.; 1 fig

  17. Time concurrency/phase-time synchronization in digital communications networks

    Science.gov (United States)

    Kihara, Masami; Imaoka, Atsushi

    1990-01-01

    Digital communications networks have the intrinsic capability of time synchronization which makes it possible for networks to supply time signals to some applications and services. A practical estimation method for the time concurrency on terrestrial networks is presented. By using this method, time concurrency capability of the Nippon Telegraph and Telephone Corporation (NTT) digital communications network is estimated to be better than 300 ns rms at an advanced level, and 20 ns rms at final level.

  18. The personal experience of time

    CERN Document Server

    Wessman, Alden

    1977-01-01

    The fundamental nature of human time experience has concerned artists, poets, philosophers, and scientists throughout the ages. Any consideration of human action requires awareness of its temporal aspects. However, simply to view time in the same units and dimensions as the physicist employs in describing events robs personal time of its "lived" quality. The use of physical time concepts in the description of human events is often artificial and misleading. It fails to account for the facts that human time estimates rarely match clock and calendar time; that societies and individuals demonstrate vast differences in their constructions and uses of time; and that temporal perceptions and attitudes change within an individual both during a single day and throughout his life span. The present volume does not view time as something that is sensed in the same way that one would sense or perceive spatial or sensory stimuli. Rather, it views time as a complex set of personally experienced cognitive constructs used by...

  19. Unit-time scheduling problems with time dependent resources

    NARCIS (Netherlands)

    Tautenhahn, T.; Woeginger, G.

    1997-01-01

    We investigate the computational complexity of scheduling problems, where the operations consume certain amounts of renewable resources which are available in time-dependent quantities. In particular, we consider unit-time open shop problems and unit-time scheduling problems with identical parallel

  20. Space-Time Crystal and Space-Time Group.

    Science.gov (United States)

    Xu, Shenglong; Wu, Congjun

    2018-03-02

    Crystal structures and the Bloch theorem play a fundamental role in condensed matter physics. We extend the static crystal to the dynamic "space-time" crystal characterized by the general intertwined space-time periodicities in D+1 dimensions, which include both the static crystal and the Floquet crystal as special cases. A new group structure dubbed a "space-time" group is constructed to describe the discrete symmetries of a space-time crystal. Compared to space and magnetic groups, the space-time group is augmented by "time-screw" rotations and "time-glide" reflections involving fractional translations along the time direction. A complete classification of the 13 space-time groups in one-plus-one dimensions (1+1D) is performed. The Kramers-type degeneracy can arise from the glide time-reversal symmetry without the half-integer spinor structure, which constrains the winding number patterns of spectral dispersions. In 2+1D, nonsymmorphic space-time symmetries enforce spectral degeneracies, leading to protected Floquet semimetal states. We provide a general framework for further studying topological properties of the (D+1)-dimensional space-time crystal.

  1. The clock that times us : Electromagnetic signatures of time estimation

    NARCIS (Netherlands)

    Kononowicz, Tadeusz Władysław

    2015-01-01

    As time is a fundamental dimension of our existence, perceiving the flow of time is an ubiquitous experience of our everyday life. This so-called sense of time is utilized in our everyday activities, for example, when we expect some events to happen, but it also prevents us from taking a morning

  2. Real time process algebra with time-dependent conditions

    NARCIS (Netherlands)

    Baeten, J.C.M.; Middelburg, C.A.

    We extend the main real time version of ACP presented in [6] with conditionals in which the condition depends on time. This extension facilitates flexible dependence of proccess behaviour on initialization time. We show that the conditions concerned generalize the conditions introduced earlier

  3. Introduction to Time Series Modeling

    CERN Document Server

    Kitagawa, Genshiro

    2010-01-01

    In time series modeling, the behavior of a certain phenomenon is expressed in relation to the past values of itself and other covariates. Since many important phenomena in statistical analysis are actually time series and the identification of conditional distribution of the phenomenon is an essential part of the statistical modeling, it is very important and useful to learn fundamental methods of time series modeling. Illustrating how to build models for time series using basic methods, "Introduction to Time Series Modeling" covers numerous time series models and the various tools f

  4. The soundscape dynamics of human agglomeration

    International Nuclear Information System (INIS)

    Ribeiro, Haroldo V; De Souza, Rodolfo T; Lenzi, Ervin K; Mendes, Renio S; Evangelista, Luiz R

    2011-01-01

    We report on a statistical analysis of the people agglomeration soundscape. Specifically, we investigate the normalized sound amplitudes and intensities that emerge from human collective meetings. Our findings support the existence of non-trivial dynamics characterized by heavy tail distributions in the sound amplitudes, long-range correlations in the sound intensity and non-exponential distributions in the return interval distributions. Additionally, motivated by the time-dependent behavior present in the volatility/variance series, we compare the observational data with those obtained from a minimalist autoregressive stochastic model, namely the generalized autoregressive conditional heteroskedastic process (the GARCH process), and find that there is good agreement.

  5. On Modelling Long Term Stock Returns with Ergodic Diffusion Processes: Arbitrage and Arbitrage-Free Specifications

    Directory of Open Access Journals (Sweden)

    Bernard Wong

    2009-01-01

    martingale component is based on an ergodic diffusion with a specified stationary distribution. These models are particularly useful for long horizon asset-liability management as they allow the modelling of long term stock returns with heavy tail ergodic diffusions, with tractable, time homogeneous dynamics, and which moreover admit a complete financial market, leading to unique pricing and hedging strategies. Unfortunately the standard specifications of these models in literature admit arbitrage opportunities. We investigate in detail the features of the existing model specifications which create these arbitrage opportunities and consequently construct a modification that is arbitrage free.

  6. Lectures on insurance models

    CERN Document Server

    Ramasubramanian, S

    2009-01-01

    Insurance has become a necessary aspect of modern society. The mathematical basis of insurance modeling is best expressed in terms of continuous time stochastic processes. This introductory text on actuarial risk theory deals with the Cramer-Lundberg model and the renewal risk model. Their basic structure and properties, including the renewal theorems as well as the corresponding ruin problems, are studied. There is a detailed discussion of heavy tailed distributions, which have become increasingly relevant. The Lundberg risk process with investment in risky asset is also considered. This book will be useful to practitioners in the field and to graduate students interested in this important branch of applied probability.

  7. Hippocampal “Time Cells”: Time versus Path Integration

    Science.gov (United States)

    Kraus, Benjamin J.; Robinson, Robert J.; White, John A.; Eichenbaum, Howard; Hasselmo, Michael E.

    2014-01-01

    SUMMARY Recent studies have reported the existence of hippocampal “time cells,” neurons that fire at particular moments during periods when behavior and location are relatively constant. However, an alternative explanation of apparent time coding is that hippocampal neurons “path integrate” to encode the distance an animal has traveled. Here, we examined hippocampal neuronal firing patterns as rats ran in place on a treadmill, thus “clamping” behavior and location, while we varied the treadmill speed to distinguish time elapsed from distance traveled. Hippocampal neurons were strongly influenced by time and distance, and less so by minor variations in location. Furthermore, the activity of different neurons reflected integration over time and distance to varying extents, with most neurons strongly influenced by both factors and some significantly influenced by only time or distance. Thus, hippocampal neuronal networks captured both the organization of time and distance in a situation where these dimensions dominated an ongoing experience. PMID:23707613

  8. Underwater Time Service and Synchronization Based on Time Reversal Technique

    Science.gov (United States)

    Lu, Hao; Wang, Hai-bin; Aissa-El-Bey, Abdeldjalil; Pyndiah, Ramesh

    2010-09-01

    Real time service and synchronization are very important to many underwater systems. But the time service and synchronization in existence cannot work well due to the multi-path propagation and random phase fluctuation of signals in the ocean channel. The time reversal mirror technique can realize energy concentration through self-matching of the ocean channel and has very good spatial and temporal focusing properties. Based on the TRM technique, we present the Time Reversal Mirror Real Time service and synchronization (TRMRT) method which can bypass the processing of multi-path on the server side and reduce multi-path contamination on the client side. So TRMRT can improve the accuracy of time service. Furthermore, as an efficient and precise method of time service, TRMRT could be widely used in underwater exploration activities and underwater navigation and positioning systems.

  9. Time and Standards - An Overview

    National Research Council Canada - National Science Library

    Guinot, Bernard

    2000-01-01

    ...? This paper attempts to answer this question. After recalling current performances of time and frequency standards and their use in establishing time scales, the author considers their limitations in astronomical observations and studies...

  10. GPS Position Time Series @ JPL

    Science.gov (United States)

    Owen, Susan; Moore, Angelyn; Kedar, Sharon; Liu, Zhen; Webb, Frank; Heflin, Mike; Desai, Shailen

    2013-01-01

    Different flavors of GPS time series analysis at JPL - Use same GPS Precise Point Positioning Analysis raw time series - Variations in time series analysis/post-processing driven by different users. center dot JPL Global Time Series/Velocities - researchers studying reference frame, combining with VLBI/SLR/DORIS center dot JPL/SOPAC Combined Time Series/Velocities - crustal deformation for tectonic, volcanic, ground water studies center dot ARIA Time Series/Coseismic Data Products - Hazard monitoring and response focused center dot ARIA data system designed to integrate GPS and InSAR - GPS tropospheric delay used for correcting InSAR - Caltech's GIANT time series analysis uses GPS to correct orbital errors in InSAR - Zhen Liu's talking tomorrow on InSAR Time Series analysis

  11. Systems, Shocks and Time Bombs

    Science.gov (United States)

    Winder, Nick

    The following sections are included: * Introduction * Modelling strategies * Are time-bomb phenomena important? * Heuristic approaches to time-bomb phenomena * Three rational approaches to TBP * Two irrational approaches * Conclusions * References

  12. Status of time reversal invariance

    International Nuclear Information System (INIS)

    Henley, E.M.

    1989-01-01

    Time Reversal Invariance is introduced, and theories for its violation are reviewed. The present experimental and theoretical status of Time Reversal Invariance and tests thereof will be presented. Possible future tests will be discussed. 30 refs., 2 figs., 1 tab

  13. Time Warp Operating System (TWOS)

    Science.gov (United States)

    Bellenot, Steven F.

    1993-01-01

    Designed to support parallel discrete-event simulation, TWOS is complete implementation of Time Warp mechanism - distributed protocol for virtual time synchronization based on process rollback and message annihilation.

  14. Ovation Prime Real-Time

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ovation Prime Real-Time (OPRT) product is a real-time forecast and nowcast model of auroral power and is an operational implementation of the work by Newell et...

  15. Time-adjusted variable resistor

    Science.gov (United States)

    Heyser, R. C.

    1972-01-01

    Timing mechanism was developed effecting extremely precisioned highly resistant fixed resistor. Switches shunt all or portion of resistor; effective resistance is varied over time interval by adjusting switch closure rate.

  16. Introduction to time reversal theory

    International Nuclear Information System (INIS)

    Henley, E.M.

    1987-01-01

    Theory and reaction mechanisms relevant to time reversal invariance are reviewed. Consequences of time reversal invariance are presented under the headings of CP tests, electromagnetic moments, weak emissions or absorptions, and scattering reactions. 8 refs., 4 figs

  17. Time: the enigma of space

    Science.gov (United States)

    Yu, Francis T. S.

    2017-08-01

    In this article we have based on the laws of physics to illustrate the enigma time as creating our physical space (i.e., the universe). We have shown that without time there would be no physical substances, no space and no life. In reference to Einstein's energy equation, we see that energy and mass can be traded, and every mass can be treated as an Energy Reservoir. We have further shown that physical space cannot be embedded in absolute empty space and cannot have any absolute empty subspace in it. Since all physical substances existed with time, our cosmos is created by time and every substance including our universe is coexisted with time. Although time initiates the creation, it is the physical substances which presented to us the existence of time. We are not alone with almost absolute certainty. Someday we may find a right planet, once upon a time, had harbored a civilization for a short period of light years.

  18. Travel time data collection handbook

    Science.gov (United States)

    1998-03-01

    This Travel Time Data Collection Handbook provides guidance to transportation : professionals and practitioners for the collection, reduction, and presentation : of travel time data. The handbook should be a useful reference for designing : travel ti...

  19. Time travel in Goedel's space

    International Nuclear Information System (INIS)

    Pfarr, J.

    1981-01-01

    An analysis is presented of the motion of test particles in Goedel's universe. Both geodesical and nongeodesical motions are considered; the accelerations for nongeodesical motions are given. Examples for closed timelike world lines are shown and the dynamical conditions for time travel in Goedel's space-time are discussed. It is shown that these conditions alone do not suffice to exclude time travel in Goedel's space-time. (author)

  20. Time-Space Topology Optimization

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    2008-01-01

    A method for space-time topology optimization is outlined. The space-time optimization strategy produces structures with optimized material distributions that vary in space and in time. The method is demonstrated for one-dimensional wave propagation in an elastic bar that has a time-dependent Young......’s modulus and is subjected to a transient load. In the example an optimized dynamic structure is demonstrated that compresses a propagating Gauss pulse....

  1. Timing analysis of safety properties using fault trees with time dependencies and timed state-charts

    International Nuclear Information System (INIS)

    Magott, Jan; Skrobanek, Pawel

    2012-01-01

    Behavior in time domain is often crucial for safety critical systems. Standard fault trees cannot express time-dependent behavior. In the paper, timing analysis of safety properties using fault trees with time dependencies (FTTDs) and timed state-charts is presented. A new version of timed state-charts (TSCs) is also proposed. These state-charts can model the dynamics of technical systems, e.g. controllers, controlled objects, and people. In TSCs, activity and communication times are represented by time intervals. In the proposed approach the structure of FTTD is fixed by a human. Time properties of events and gates of FTTD are expressed by time intervals, and are calculated using TSCs. The minimal and maximal values of these time intervals of FTTD can be calculated by finding paths with minimal and maximal time lengths in TSCs, which is an NP-hard problem. In order to reduce the practical complexity of computing the FTTD time parameters, some reductions of TSCs are defined in the paper, such as sequential, alternative, loop (iteration), and parallel. Some of the reductions are intuitive, in case of others—theorems are required. Computational complexity of each reduction is not greater than linear in the size of reduced TSC. Therefore, the obtained results enable decreasing of the costs of FTTD time parameters calculation when system dynamics is expressed by TSCs. Case study of a railroad crossing with a controller that controls semaphores, gate, light-audio signal close to the gate will be analyzed.

  2. Time resolved techniques: An overview

    International Nuclear Information System (INIS)

    Larson, B.C.; Tischler, J.Z.

    1990-06-01

    Synchrotron sources provide exceptional opportunities for carrying out time-resolved x-ray diffraction investigations. The high intensity, high angular resolution, and continuously tunable energy spectrum of synchrotron x-ray beams lend themselves directly to carrying out sophisticated time-resolved x-ray scattering measurements on a wide range of materials and phenomena. When these attributes are coupled with the pulsed time-structure of synchrotron sources, entirely new time-resolved scattering possibilities are opened. Synchrotron beams typically consist of sub-nanosecond pulses of x-rays separated in time by a few tens of nanoseconds to a few hundred nanoseconds so that these beams appear as continuous x-ray sources for investigations of phenomena on time scales ranging from hours down to microseconds. Studies requiring time-resolution ranging from microseconds to fractions of a nanosecond can be carried out in a triggering mode by stimulating the phenomena under investigation in coincidence with the x-ray pulses. Time resolution on the picosecond scale can, in principle, be achieved through the use of streak camera techniques in which the time structure of the individual x-ray pulses are viewed as quasi-continuous sources with ∼100--200 picoseconds duration. Techniques for carrying out time-resolved scattering measurements on time scales varying from picoseconds to kiloseconds at present and proposed synchrotron sources are discussed and examples of time-resolved studies are cited. 17 refs., 8 figs

  3. Establishing Time for Professional Learning

    Science.gov (United States)

    Journal of Staff Development, 2013

    2013-01-01

    Time for collaborative learning is an essential resource for educators working to implement college- and career-ready standards. The pages in this article include tools from the workbook "Establishing Time for Professional Learning." The tools support a complete process to help educators effectively find and use time. The following…

  4. Time tunnels meet warped passages

    CERN Multimedia

    Kushner, David

    2006-01-01

    "Just in time for its 40th anniversary, the classic sci-fi television show "The time tunnel" is out on DVD. The conceit is something every engineer can relate to: a pulled plug. Scientists in an underground lab are working on a secret government experiment in time travel. (1 page)

  5. Growth with Time Zone Differences

    OpenAIRE

    Toru Kikuchi; Sugata Marjit

    2010-01-01

    We propose a two-country growth model of intermediate business-services trade that captures the role of time zone differences. It is shown that a time-saving improvement in intermediate business-services trade involving production in different time zones can have a permanent impact on productivity.

  6. Time management: a realistic approach.

    Science.gov (United States)

    Jackson, Valerie P

    2009-06-01

    Realistic time management and organization plans can improve productivity and the quality of life. However, these skills can be difficult to develop and maintain. The key elements of time management are goals, organization, delegation, and relaxation. The author addresses each of these components and provides suggestions for successful time management.

  7. Time Management of Educational Inspectors

    Science.gov (United States)

    Göksoy, Süleyman

    2015-01-01

    The aim of the research is to determine the fields that Educational Inspectors have to spare time for and the fields that Educational Inspectors demand to make time for. The data collected by review form was analyzed by content analysis method. According to research results: Educational Inspectors want to make time mostly for counselling and…

  8. Mixed Hitting-Time Models

    NARCIS (Netherlands)

    Abbring, J.H.

    2009-01-01

    We study mixed hitting-time models, which specify durations as the first time a Levy process (a continuous-time process with stationary and independent increments) crosses a heterogeneous threshold. Such models of substantial interest because they can be reduced from optimal-stopping models with

  9. From Networks to Time Series

    Science.gov (United States)

    Shimada, Yutaka; Ikeguchi, Tohru; Shigehara, Takaomi

    2012-10-01

    In this Letter, we propose a framework to transform a complex network to a time series. The transformation from complex networks to time series is realized by the classical multidimensional scaling. Applying the transformation method to a model proposed by Watts and Strogatz [Nature (London) 393, 440 (1998)], we show that ring lattices are transformed to periodic time series, small-world networks to noisy periodic time series, and random networks to random time series. We also show that these relationships are analytically held by using the circulant-matrix theory and the perturbation theory of linear operators. The results are generalized to several high-dimensional lattices.

  10. The LCLS Timing Event System

    Energy Technology Data Exchange (ETDEWEB)

    Dusatko, John; Allison, S.; Browne, M.; Krejcik, P.; /SLAC

    2012-07-23

    The Linac Coherent Light Source requires precision timing trigger signals for various accelerator diagnostics and controls at SLAC-NAL. A new timing system has been developed that meets these requirements. This system is based on COTS hardware with a mixture of custom-designed units. An added challenge has been the requirement that the LCLS Timing System must co-exist and 'know' about the existing SLC Timing System. This paper describes the architecture, construction and performance of the LCLS timing event system.

  11. Reforming "Time" in Danish Schools?

    DEFF Research Database (Denmark)

    Vaaben, Nana Katrine

    with "time", to paying them for "time". This implied a shift from a notion of time similar to a currency (teachers were paid for specific tasks/responsibilities with "hours"), to a notion of time as an abstract and empty category which (following a Marxian approach) anything can be put. The article...... into a better and more productive future by getting rid of old-fashioned working time systems constituting barriers to efficient and flexible use of resources (Udvalget om analyse af folkeskolelærernes arbejdstid et al. 2006; Udvalget om analyse af folkeskolelærernes arbejdstid et al. 2007). In stead...

  12. Sensory adaptation for timing perception.

    Science.gov (United States)

    Roseboom, Warrick; Linares, Daniel; Nishida, Shin'ya

    2015-04-22

    Recent sensory experience modifies subjective timing perception. For example, when visual events repeatedly lead auditory events, such as when the sound and video tracks of a movie are out of sync, subsequent vision-leads-audio presentations are reported as more simultaneous. This phenomenon could provide insights into the fundamental problem of how timing is represented in the brain, but the underlying mechanisms are poorly understood. Here, we show that the effect of recent experience on timing perception is not just subjective; recent sensory experience also modifies relative timing discrimination. This result indicates that recent sensory history alters the encoding of relative timing in sensory areas, excluding explanations of the subjective phenomenon based only on decision-level changes. The pattern of changes in timing discrimination suggests the existence of two sensory components, similar to those previously reported for visual spatial attributes: a lateral shift in the nonlinear transducer that maps relative timing into perceptual relative timing and an increase in transducer slope around the exposed timing. The existence of these components would suggest that previous explanations of how recent experience may change the sensory encoding of timing, such as changes in sensory latencies or simple implementations of neural population codes, cannot account for the effect of sensory adaptation on timing perception.

  13. Master timing and TOF module

    International Nuclear Information System (INIS)

    Mazaheri, G.

    1991-11-01

    In conjunction with the development of a Beam Size Monitor (BSM) for the Final Focus Test Beam (FFTB) at SLAC, we have built a general purpose timing device with capabilities useful for many different applications. The Time Master consists of a fast clock, a large memory loaded via a PC, and a time vernier (analog) with 8-bit resolution. The Time Master generates an arbitrary pattern of pulses on 16 different channels (up to 256), with a resolution of 1/2 8 times the clock period. The clock content is stored in another memory to measure the time of up to 16 channels, with a resolution of 1/2 8 times the clock period (frequency is set at 50 Mhz), using a time-to-amplitude vernier. The data stored in the memory is accessed via a PC. The depth of the memory for pattern generation is 15 bits (32767), equal to the depth of the time measuring part. The device is self-calibrating, simply by prescribing a pattern on the output channels, and reading it into the time measuring section. The total clock length is 24 bits, equivalent to 334 ms of time at 50 Mhz frequency. Therefore, the resolution is of the order of 32 bits (i.e., 24 bits of clock plus 8 bits of vernier). 2 refs., 2 figs

  14. Timed-Arc Petri Nets vs. Networks of Timed Automata

    DEFF Research Database (Denmark)

    Srba, Jiri

    We establish mutual translations between the classes of 1-safe timed-arc Petri nets (and its extension with testing arcs) and networks of timed automata (and its subclass where every clock used in the guard has to be reset). The presented translations are very tight (up to isomorphism of labelled...... transition systems with time). This provides a convenient characterization from the theoretical point of view but is not always satisfactory from the practical point of view because of the possible non-polynomial blow up in the size (in the direction from automata to nets). Hence we relax the isomorphism...... requirement and provide efficient (polynomial time) reductions between networks of timed automata and 1-safe timed-arc Petri nets preserving the answer to the reachability question. This makes our techniques suitable for automatic translation into a format required by tools like UPPAAL and KRONOS. A direct...

  15. Language Emptiness of Continuous-Time Parametric Timed Automata

    DEFF Research Database (Denmark)

    Benes, Nikola; Bezdek, Peter; Larsen, Kim Guldstrand

    2015-01-01

    Parametric timed automata extend the standard timed automata with the possibility to use parameters in the clock guards. In general, if the parameters are real-valued, the problem of language emptiness of such automata is undecidable even for various restricted subclasses. We thus focus on the case...... where parameters are assumed to be integer-valued, while the time still remains continuous. On the one hand, we show that the problem remains undecidable for parametric timed automata with three clocks and one parameter. On the other hand, for the case with arbitrary many clocks where only one......-time semantics only. To the best of our knowledge, this is the first positive result in the case of continuous-time and unbounded integer parameters, except for the rather simple case of single-clock automata....

  16. NavyTime: Event and Time Ordering from Raw Text

    Science.gov (United States)

    2013-06-01

    time-time, and event-DCT (DCT is the doc- ument creation time). 74 Event Extraction F1 ATT-1 81.05 NavyTime 80.30 KUL 79.32 cleartk -4 & cleartk -3...71.88 KUL 70.17 cleartk 67.87 NavyTime 67.48 Temp:ESA 54.55 JU-CSE 52.69 Temp:WNet 50.00 FSS-TimEx 42.94 Tense and Aspect Attributes System Tense F1...Aspect F1 cleartk 62.18 70.40 NavyTime 61.67 72.43 ATT 59.47 73.50 JU-CSE 58.62 72.14 KUL 49.70 63.20 not all systems participated Figure 1: Complete

  17. Commentary: the right time to rethink part-time careers.

    Science.gov (United States)

    Palda, Valerie A; Levinson, Wendy

    2009-01-01

    The demand for part-time academic positions is bound to increase because of the changing demographics of medicine and the needs of both women and men faculty. One of the main benefits of working part-time is the freedom to shape a career that is tailored to one's individualized life needs. Studies indicate that part-time faculty may enhance quality of care, patient satisfaction, resource utilization, and productivity. Division chiefs and department chairs who have flexible hiring policies to meet the needs of part-time faculty are likely to be more successful in recruitment and retention. The authors describe some of the benefits and drawbacks of part-time work, and they offer advice for faculty members seeking part-time careers and for leaders seeking to employ them.

  18. Customizable Time-Oriented Visualizations

    DEFF Research Database (Denmark)

    Kuhail, Mohammad Amin; Pantazos, Kostas; Lauesen, Søren

    2012-01-01

    Most commercial visualization tools support an easy and quick creation of conventional time-oriented visualizations such as line charts, but customization is limited. In contrast, some academic visualization tools and programming languages support the creation of some customizable time......-oriented visualizations but it is time consuming and hard. To combine efficiency, the effort required to develop a visualization, and customizability, the ability to tailor a visualization, we developed time-oriented building blocks that address the specifics of time (e.g. linear vs. cyclic or point-based vs. interval......-based) and consist of inner customizable parts (e.g. ticks). A combination of the time-oriented and other primitive graphical building blocks allowed the creation of several customizable advanced time-oriented visualizations. The appearance and behavior of the blocks are specified using spreadsheet-like formulas. We...

  19. Division A Commission 31: Time

    Science.gov (United States)

    Hosokawa, Mizuhiko; Arias, Elisa Felicitas; Manchester, Richard; Tuckey, Philip; Matsakis, Demetrios; Zhang, Shougang; Zharov, Vladimir

    2016-04-01

    Time is an essential element of fundamental astronomy. In recent years there have been many time-related issues, in scientific and technological aspects as well as in conventions and definitions. At the Commission 31 (Time) business meeting at the XXIX General Assembly, recent progress and many topics, including Pulsar Time Scales WG and Future UTC WG activities, were reviewed and discussed. In this report, we will review the progress of these topics in the past three years. There are many remarkable topics, such as Time scales, Atomic clock development, Time transfer, Future UTC and future redefinition of the second. Among them, scientific highlights are the progress of pulsar time scales and the optical frequency standards. On the other hand, as the social convention, change in the definition of UTC and the second is important.

  20. Worker's perceptions of time, time-use-attitudes and productivity

    OpenAIRE

    E. Ben-Baruch; C. P. H. Myburgh; E. C. Anderssen

    1991-01-01

    Decreasing productivity and increasing wage demands are singled out as being crucial problems facing the economy of South Africa. Changes in the time perceptions and time-use-attitudes of workers could play a decisive role in increasing productivity. The relationships between time perception, needs, motivation and productivity are analysed. Culture, tradition, economy, and environment lend a specific significance to these variables. Workers in a technological society should be guided to adapt...

  1. Perception, time of perception, perception of the time

    Directory of Open Access Journals (Sweden)

    Barata, André

    2009-04-01

    Full Text Available From a conceptual point of view, time is independent of its experience. That is: it can be given a conceptual description of time without any reference to terms related to the subjective consciousness of time. But concerning a phenomenology of that subjective experience of time, it can it be showed that such experience of time is, in itself, temporal. The very same terms employed in a conceptual description of time – terms like “change” and “duration”– are implied in the phenomenological description of every perception, including perception of time. This authorizes a characterization of subjective time experience as subjective time. At last, based on temporal nature of perception of time, I will suggest an explanation for our common experience of asymmetries subjective time and objective time.Desde un punto de vista conceptual, el tiempo es independiente respecto de la experiencia del tiempo. Es decir: puede darse una descripción conceptual del tiempo sin referencia ninguna a términos relacionados con la conciencia subjetiva del tiempo. Pero en lo concerniente a una fenomenología de esa experiencia subjetiva del tiempo, puede revelarse que tal experiencia de tiempo es, ella en sí misma, temporal? Los mismísimos términos empleados en una descripción conceptual del tiempo, como “cambio” y “duración”, están implicados en la descripción fenomenológica de toda percepción, incluida la percepción del tiempo. Esto autoriza una caracterización de la experiencia subjetiva del tiempo como tiempo subjetivo. Finalmente, sobre la base de la naturaleza temporal de la percepción del tiempo, sugeriré una explicación racional de nuestra experiencia común de asimetrías entre el tiempo subjetivo y el tiempo objetivo.

  2. Time-dependent friction and solvation time correlation function

    International Nuclear Information System (INIS)

    Samanta, Alok; Ali, Sk Musharaf; Ghosh, Swapan K

    2005-01-01

    We have derived a new relation between the time-dependent friction and solvation time correlation function (STCF) for non-polar fluids. The friction values calculated using this relation and simulation results on STCF for a Lennard-Jones fluid are shown to have excellent agreement with the same obtained through mode-coupling theory. Also derived is a relation between the time-dependent dielectric friction and STCF for polar fluids. Routes are thus provided to obtain the time-dependent friction (non-polar as well as dielectric) from an experimentally measured quantity like STCF, even if the interparticle interaction potential is not known

  3. Time recording unit for a neutron time of flight spectrometer

    International Nuclear Information System (INIS)

    Puranik, Praful; Ajit Kiran, S.; Chandak, R.M.; Poudel, S.K.; Mukhopadhyay, R.

    2011-01-01

    Here the architecture and design of Time Recording Unit for a Neutron Time of Flight Spectrometer have been described. The Spectrometer would have an array of 50 Nos. of one meter long linear Position Sensitive Detector (PSD) placed vertically around the sample at a distance of 2000 mm. The sample receives periodic pulsed neutron beam coming through a Fermi chopper. The time and zone of detection of a scattered neutron in a PSD gives information of its flight time and path length, which will be used to calculate its energy. A neutron event zone (position) and time detection module for each PSD provides a 2 bit position/zone code and an event timing pulse. The path length assigned to a neutron detected in a zone (Z1, Z2 etc) in the PSD is the mean path length seen by the neutrons detected in that zone of the PSD. A Time recording unit described here receives event zone code and timing pulse for all the 50 detectors, tags a proper time window code to it, before streaming it to computer for calculation of the energy distribution of neutrons scattered from the sample

  4. Time Investment and Time Management: An Analysis of Time Students Spend Working at Home for School

    Science.gov (United States)

    Wagner, Petra; Schober, Barbara; Spiel, Christiane

    2008-01-01

    This paper deals with the time students spend working at home for school. In Study 1, we investigated amount and regulation of time. Study 2 serves to validate the results of Study 1 and, in addition, investigates the duration of the time units students used and their relation to scholastic success. In Study 1, the participants were 332 students…

  5. Time allocation of disabled individuals.

    Science.gov (United States)

    Pagán, Ricardo

    2013-05-01

    Although some studies have analysed the disability phenomenon and its effect on, for example, labour force participation, wages, job satisfaction, or the use of disability pension, the empirical evidence on how disability steals time (e.g. hours of work) from individuals is very scarce. This article examines how disabled individuals allocate their time to daily activities as compared to their non-disabled counterparts. Using time diary information from the Spanish Time Use Survey (last quarter of 2002 and the first three quarters of 2003), we estimate the determinants of time (minutes per day) spent on four aggregate categories (market work, household production, tertiary activities and leisure) for a sample of 27,687 non-disabled and 5250 disabled individuals and decompose the observed time differential by using the Oaxaca-Blinder methodology. The results show that disabled individuals devote less time to market work (especially females), and more time to household production (e.g. cooking, cleaning, child care), tertiary activities (e.g., sleeping, personal care, medical treatment) and leisure activities. We also find a significant effect of age on the time spent on daily activities and important differences by gender and disability status. The results are consistent with the hypothesis that disability steals time, and reiterate the fact that more public policies are needed to balance working life and health concerns among disabled individuals. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. The Advanced LIGO timing system

    International Nuclear Information System (INIS)

    Bartos, Imre; Factourovich, Maxim; Marka, Szabolcs; Marka, Zsuzsa; Raics, Zoltan; Bork, Rolf; Heefner, Jay; Schwinberg, Paul; Sigg, Daniel

    2010-01-01

    Gravitational wave detection using a network of detectors relies upon the precise time stamping of gravitational wave signals. The relative arrival times between detectors are crucial, e.g. in recovering the source direction, an essential step in using gravitational waves for multi-messenger astronomy. Due to the large size of gravitational wave detectors, timing at different parts of a given detector also needs to be highly synchronized. In general, the requirement toward the precision of timing is determined such that, upon detection, the deduced (astro-) physical results should not be limited by the precision of timing. The Advanced LIGO optical timing distribution system is designed to provide UTC-synchronized timing information for the Advanced LIGO detectors that satisfies the above criterium. The Advanced LIGO timing system has modular structure, enabling quick and easy adaptation to the detector frame as well as possible changes or additions of components. It also includes a self-diagnostics system that enables the remote monitoring of the status of timing. After the description of the Advanced LIGO timing system, several tests are presented that demonstrate its precision and robustness.

  7. Time-resolved photoelectron spectroscopy using synchrotron radiation time structure

    International Nuclear Information System (INIS)

    Bergeard, N.; Silly, M.G.; Chauvet, C.; Guzzo, M.; Ricaud, J.P.; Izquierdo, M.; Sirotti, F.; Krizmancic, D.; Guzzo, M.; Stebel, L.; Pittana, P.; Sergo, R.; Cautero, G.; Dufour, G.; Rochet, F.

    2011-01-01

    Synchrotron radiation time structure is becoming a common tool for studying dynamic properties of materials. The main limitation is often the wide time domain the user would like to access with pump-probe experiments. In order to perform photoelectron spectroscopy experiments over time scales from milliseconds to picoseconds it is mandatory to measure the time at which each measured photoelectron was created. For this reason the usual CCD camera based two-dimensional detection of electron energy analyzers has been replaced by a new delay-line detector adapted to the time structure of the SOLEIL synchrotron radiation source. The new two-dimensional delay-line detector has a time resolution of 5 ns and was installed on a Scienta SES 2002 electron energy analyzer. The first application has been to characterize the time of flight of the photo emitted electrons as a function of their kinetic energy and the selected pass energy. By repeating the experiment as a function of the available pass energy and of the kinetic energy, a complete characterization of the analyzer behaviour in the time domain has been obtained. Even for kinetic energies as low as 10 eV at 2 eV pass energy, the time spread of the detected electrons is lower than 140 ns. These results and the time structure of the SOLEIL filling modes assure the possibility of performing pump-probe photoelectron spectroscopy experiments with the time resolution given by the SOLEIL pulse width, the best performance of the beamline and of the experimental station. (authors)

  8. Timed Online Tests: Do Students Perform Better with More Time?

    Science.gov (United States)

    Portolese, Laura; Krause, Jackie; Bonner, Julie

    2016-01-01

    This article focuses on timed tests and specifically on whether increased time enhances test performance. Three courses during the Winter 2015 term (quizzes n = 573) and three courses over the Spring 2015 term (quizzes n = 600) comprised this sample. Students were given the same tests, but the experimental group (Spring 2015) was given 50% more…

  9. Absenteeism of part-time and full-time employees

    NARCIS (Netherlands)

    Smulders, P.G.W.

    1993-01-01

    Absence of part-time employees in comparison with that of full-time employees has not received much attention in organisational research up to now. Personnel departments of three industrial firms in the Netherlands made information available with respect to personal/demographic characteristics (age,

  10. Exponential time paradigms through the polynomial time lens

    NARCIS (Netherlands)

    Drucker, A.; Nederlof, J.; Santhanam, R.; Sankowski, P.; Zaroliagis, C.

    2016-01-01

    We propose a general approach to modelling algorithmic paradigms for the exact solution of NP-hard problems. Our approach is based on polynomial time reductions to succinct versions of problems solvable in polynomial time. We use this viewpoint to explore and compare the power of paradigms such as

  11. Long-time data storage: relevant time scales

    NARCIS (Netherlands)

    Elwenspoek, Michael Curt

    2011-01-01

    Dynamic processes relevant for long-time storage of information about human kind are discussed, ranging from biological and geological processes to the lifecycle of stars and the expansion of the universe. Major results are that life will end ultimately and the remaining time that the earth is

  12. 76 FR 61947 - Timely Mailing Treated as Timely Filing

    Science.gov (United States)

    2011-10-06

    ... regulations affect taxpayers who mail Federal tax documents to the Internal Revenue Service or the United... DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR Part 301 [TD 9543] RIN 1545-BA99 Timely Mailing Treated as Timely Filing AGENCY: Internal Revenue Service, Treasury. ACTION: Correcting amendment...

  13. 76 FR 62607 - Timely Mailing Treated as Timely Filing

    Science.gov (United States)

    2011-10-11

    ... affect taxpayers who mail Federal tax documents to the Internal Revenue service or the United States Tax... DEPARTMENT OF THE TREASURY Internal Revenue Service 26 CFR Part 301 [TD 9543] RIN 1545-BA99 Timely Mailing Treated as Timely Filing AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Correction to...

  14. Modern Times: The Industrial Revolution and the Concept of Time.

    Science.gov (United States)

    Doppen, Frans H.

    1999-01-01

    Discusses the role the Industrial Revolution had in changing humankind's perception of time and recommends using the flashback approach in order to encourage students to think about how the process of industrialization still affects their lives. Provides activities that address the concept of time caused by the Industrial Revolution. (CMK)

  15. Timing calibration and spectral cleaning of LOFAR time series data

    NARCIS (Netherlands)

    Corstanje, A.; Buitink, S.; Enriquez, J. E.; Falcke, H.; Horandel, J. R.; Krause, M.; Nelles, A.; Rachen, J. P.; Schellart, P.; Scholten, O.; ter Veen, S.; Thoudam, S.; Trinh, T. N. G.

    We describe a method for spectral cleaning and timing calibration of short time series data of the voltage in individual radio interferometer receivers. It makes use of phase differences in fast Fourier transform (FFT) spectra across antenna pairs. For strong, localized terrestrial sources these are

  16. Time-Predictable Virtual Memory

    DEFF Research Database (Denmark)

    Puffitsch, Wolfgang; Schoeberl, Martin

    2016-01-01

    Virtual memory is an important feature of modern computer architectures. For hard real-time systems, memory protection is a particularly interesting feature of virtual memory. However, current memory management units are not designed for time-predictability and therefore cannot be used...... in such systems. This paper investigates the requirements on virtual memory from the perspective of hard real-time systems and presents the design of a time-predictable memory management unit. Our evaluation shows that the proposed design can be implemented efficiently. The design allows address translation...... and address range checking in constant time of two clock cycles on a cache miss. This constant time is in strong contrast to the possible cost of a miss in a translation look-aside buffer in traditional virtual memory organizations. Compared to a platform without a memory management unit, these two additional...

  17. Machine-Checkable Timed CSP

    Science.gov (United States)

    Goethel, Thomas; Glesner, Sabine

    2009-01-01

    The correctness of safety-critical embedded software is crucial, whereas non-functional properties like deadlock-freedom and real-time constraints are particularly important. The real-time calculus Timed Communicating Sequential Processes (CSP) is capable of expressing such properties and can therefore be used to verify embedded software. In this paper, we present our formalization of Timed CSP in the Isabelle/HOL theorem prover, which we have formulated as an operational coalgebraic semantics together with bisimulation equivalences and coalgebraic invariants. Furthermore, we apply these techniques in an abstract specification with real-time constraints, which is the basis for current work in which we verify the components of a simple real-time operating system deployed on a satellite.

  18. Concurrent systems and time synchronization

    Science.gov (United States)

    Burgin, Mark; Grathoff, Annette

    2018-05-01

    In the majority of scientific fields, system dynamics is described assuming existence of unique time for the whole system. However, it is established theoretically, for example, in relativity theory or in the system theory of time, and validated experimentally that there are different times and time scales in a variety of real systems - physical, chemical, biological, social, etc. In spite of this, there are no wide-ranging scientific approaches to exploration of such systems. Therefore, the goal of this paper is to study systems with this property. We call them concurrent systems because processes in them can go, events can happen and actions can be performed in different time scales. The problem of time synchronization is specifically explored.

  19. Time Breath of Psychological Theories

    DEFF Research Database (Denmark)

    Tateo, Luca; Valsiner, Jaan

    2015-01-01

    Psychology as a self-aspiring, ambitious, developmental science faces the crucial limit of time—both theoretically and practically. The issue of time in constructing psychology’s theories is a major unresolved metatheoretical task. This raises several questions about generalization of knowledge...... of time—or fail to do that? How can they generalize with respect to time? The different conceptions of time often remain implicit, while shaping the concepts used in understanding psychological processes. Any preconception about time in human development will foster the generalizability of theory, as well......: which is the time length of breath of psychological theories? Which is the temporal dimension of psychological processes? In this article we discuss the role of different axiomatic assumptions about time in the construction of psychological theories. How could different theories include a concept...

  20. Approaches to groundwater travel time

    International Nuclear Information System (INIS)

    Kaplan, P.; Klavetter, E.; Peters, R.

    1989-01-01

    One of the objectives of performance assessment for the Yucca Mountain Project is to estimate the groundwater travel time at Yucca Mountain, Nevada, to determine whether the site complies with the criteria specified in the Code of Federal Regulations, Title 10 CFR 60.113 (a). The numerical standard for performance in these criteria is based on the groundwater travel time along the fastest path of likely radionuclide transport from the disturbed zone to the accessible environment. The concept of groundwater travel time as proposed in the regulations, does not have a unique mathematical statement. The purpose of this paper is to discuss the ambiguities associated with the regulatory specification of groundwater travel time, two different interpretations of groundwater travel time, and the effect of the two interpretations on estimates of the groundwater travel time

  1. Versatile timing system for MFTF

    International Nuclear Information System (INIS)

    Lau, N.H.C.

    1981-01-01

    This System consists of the Master Timing Transmitter and the Local Timing Receivers. The Master Timing Transmitter located in the control room initiates timing messages, abort messages and precise delay messages. A sync message is sent when one of the other three is not being sent. The Local Timing Receiver, located in the equipment area, decodes the incoming messages and generates 6 MHz, 3MHz and 1 MHz continuous clocks. A 250 KHz sync clock is derived from the sync messages, to which all pulse outputs are synchronized. The Local Timing Receiver also provides two ON-OFF delay counters of 64 bits each, and one OFF delay counter of 32 bits. Detection of abort messages and an out-of-sync signal will automatically disable all outputs

  2. Absence of Quantum Time Crystals.

    Science.gov (United States)

    Watanabe, Haruki; Oshikawa, Masaki

    2015-06-26

    In analogy with crystalline solids around us, Wilczek recently proposed the idea of "time crystals" as phases that spontaneously break the continuous time translation into a discrete subgroup. The proposal stimulated further studies and vigorous debates whether it can be realized in a physical system. However, a precise definition of the time crystal is needed to resolve the issue. Here we first present a definition of time crystals based on the time-dependent correlation functions of the order parameter. We then prove a no-go theorem that rules out the possibility of time crystals defined as such, in the ground state or in the canonical ensemble of a general Hamiltonian, which consists of not-too-long-range interactions.

  3. Towards Real-Time Argumentation

    Directory of Open Access Journals (Sweden)

    Vicente JULIÁN

    2016-07-01

    Full Text Available In this paper, we deal with the problem of real-time coordination with the more general approach of reaching real-time agreements in MAS. Concretely, this work proposes a real-time argumentation framework in an attempt to provide agents with the ability of engaging in argumentative dialogues and come with a solution for their underlying agreement process within a bounded period of time. The framework has been implemented and evaluated in the domain of a customer support application. Concretely, we consider a society of agents that act on behalf of a group of technicians that must solve problems in a Technology Management Centre (TMC within a bounded time. This centre controls every process implicated in the provision of technological and customer support services to private or public organisations by means of a call centre. The contract signed between the TCM and the customer establishes penalties if the specified time is exceeded.

  4. Expiration Times for Data Management

    DEFF Research Database (Denmark)

    Schmidt, Albrecht; Jensen, Christian Søndergaard; Saltenis, Simonas

    2006-01-01

    This paper describes an approach to incorporating the notion of expiration time into data management based on the relational model. Expiration times indicate when tuples cease to be current in a database. The paper presents a formal data model and a query algebra that handle expiration times...... transparently and declaratively. In particular, expiration times are exposed to users only on insertion and update, and when triggers fire due to the expiration of a tuple; for queries, they are handled behind the scenes and do not concern the user. Notably, tuples are removed automatically from (materialised......) query results as they expire in the (base) relations. For application developers, the benefits of using expiration times are (1) leaner application code, (2) lower transaction volume, (3) smaller databases, and, (4) higher consistency for replicated data with lower overhead. Expiration times turn out...

  5. VULNERABILITY OF PART TIME EMPLOYEES

    Directory of Open Access Journals (Sweden)

    Raluca Dimitriu

    2015-11-01

    Full Text Available The employee who concluded a part-time contract is the employee whose normal working hours, calculated weekly or as monthly average, is lower than the number of normal working hours of a comparable full-time employee. Part-time workers generally have the same legal status as full time workers. In fact, the vulnerability of this category of workers is not necessarily legal but rather economic: income - in proportion to the work performed, may be insufficient to cover the needs of living. However, such vulnerability may also have a certain cultural component: in some societies, professional identity is determined by the length of working hours. Also, part time work may hide many types of indirect discrimination.As a result, the part-time contract requires more than a protective legislation: it requires a strategy. This paper proposes a number of milestones of such a strategy, as well as some concrete de lege ferenda proposals.

  6. Approaches to groundwater travel time

    International Nuclear Information System (INIS)

    Kaplan, P.; Klavetter, E.; Peters, R.

    1989-01-01

    One of the objectives of performance assessment for the Yucca Mountain Project is to estimate the groundwater travel time at Yucca Mountain, Nevada, to determine whether the site complies with the criteria specified in the Code of Federal Regulations. The numerical standard for performance in these criteria is based on the groundwater travel time along the fastest path of likely radionuclide transport from the disturbed zone to the accessible environment. The concept of groundwater travel time, as proposed in the regulations, does not have a unique mathematical statement. The purpose of this paper is to discuss (1) the ambiguities associated with the regulatory specification of groundwater travel time, (2) two different interpretations of groundwater travel time, and (3) the effect of the two interpretations on estimates of the groundwater travel time. 3 refs., 2 figs., 2 tabs

  7. Build your own time machine

    CERN Document Server

    Clegg, Brian

    2012-01-01

    There is no physical law to prevent time travel nothing in physics to say it is impossible. So who is to say it can't be done? In Build Your Own Time Machine, acclaimed science writer Brian Clegg takes inspiration from his childhood heroes, Doctor Who and H. G. Wells, to explain the nature of time. How do we understand it and why measure it the way we do? How did the theories of one man change the way time was perceived by the world? Why wouldn't H. G. Wells's time machine have worked? And what would we need to do to make a real one? Build Your Own Time Machine explores the amazing possib

  8. Time management training and perceived control of time at work.

    Science.gov (United States)

    Häfner, Alexander; Stock, Armin

    2010-01-01

    The purpose of the present study was to examine the effects of time management training, which was based on psychological theory and research, on perceived control of time, perceived stress, and performance at work. The authors randomly assigned 71 employees to a training group (n = 35) or a waiting-list control group (n = 36). As hypothesized, time management training led to an increase in perceived control of time and a decrease in perceived stress. Time management training had no impact on different performance indicators. In particular, the authors explored the use and the perceived usefulness of the techniques taught. Participants judged the taught techniques as useful, but there were large differences concerning the actual use of the various techniques.

  9. Time scarcity: another health inequality?

    OpenAIRE

    Lyndall Strazdins; Amy L Griffin; Dorothy H Broom; Cathy Banwell; Rosemary Korda; Jane Dixon; Francesco Paolucci; John Glover

    2011-01-01

    Considerable policy action has focused on the social patterning of health, especially the health risks associated with low income. More recent attention has turned to transport, food systems, workplaces, and location, and the way their intersections with social position and income create health inequalities. Time is another dimension that structures what people do; yet the way in which time contours health has been neglected. This paper explores (a) how time might influence health, and (b) th...

  10. Development of TIME2 code

    International Nuclear Information System (INIS)

    1986-02-01

    The paper reviews the progress on the development of a computer model TIME2, for modelling the long term evolution of shallow burial site environments for low- and intermediate-level radioactive waste disposal. The subject is discussed under the five topic headings: 1) background studies, including geomorphology, climate, human-induced effects, and seismicity, 2) development of the TIME2 code, 3) verification and testing, 4) documentation, and, 5) role of TIME2 in radiological risk assessment. (U.K.)

  11. Noisy time-dependent spectra

    International Nuclear Information System (INIS)

    Shore, B.W.; Eberly, J.H.

    1983-01-01

    The definition of a time-dependent spectrum registered by an idealized spectrometer responding to a time-varying electromagnetic field as proposed by Eberly and Wodkiewicz and subsequently applied to the spectrum of laser-induced fluorescence by Eberly, Kunasz, and Wodkiewicz is here extended to allow a stochastically fluctuating (interruption model) environment: we provide an algorithm for numerical determination of the time-dependent fluorescence spectrum of an atom subject to excitation by an intense noisy laser and interruptive relaxation

  12. FDTD Stability: Critical Time Increment

    OpenAIRE

    Z. Skvor; L. Pauk

    2003-01-01

    A new approach suitable for determination of the maximal stable time increment for the Finite-Difference Time-Domain (FDTD) algorithm in common curvilinear coordinates, for general mesh shapes and certain types of boundaries is presented. The maximal time increment corresponds to a characteristic value of a Helmholz equation that is solved by a finite-difference (FD) method. If this method uses exactly the same discretization as the given FDTD method (same mesh, boundary conditions, order of ...

  13. Time Series with Long Memory

    OpenAIRE

    西埜, 晴久

    2004-01-01

    The paper investigates an application of long-memory processes to economic time series. We show properties of long-memory processes, which are motivated to model a long-memory phenomenon in economic time series. An FARIMA model is described as an example of long-memory model in statistical terms. The paper explains basic limit theorems and estimation methods for long-memory processes in order to apply long-memory models to economic time series.

  14. Real-time holographic endoscopy

    Science.gov (United States)

    Smigielski, Paul; Albe, Felix; Dischli, Bernard

    1992-08-01

    Some new experiments concerning holographic endoscopy are presented. The quantitative measurements of deformations of objects are obtained by the double-exposure and double- reference beam method, using either a cw-laser or a pulsed laser. Qualitative experiments using an argon laser with time-average holographic endoscopy are also presented. A video film on real-time endoscopic holographic interferometry was recorded with the help of a frequency-doubled YAG-laser working at 25 Hz for the first time.

  15. Principles of discrete time mechanics

    CERN Document Server

    Jaroszkiewicz, George

    2014-01-01

    Could time be discrete on some unimaginably small scale? Exploring the idea in depth, this unique introduction to discrete time mechanics systematically builds the theory up from scratch, beginning with the historical, physical and mathematical background to the chronon hypothesis. Covering classical and quantum discrete time mechanics, this book presents all the tools needed to formulate and develop applications of discrete time mechanics in a number of areas, including spreadsheet mechanics, classical and quantum register mechanics, and classical and quantum mechanics and field theories. A consistent emphasis on contextuality and the observer-system relationship is maintained throughout.

  16. Chemical control of flowering time

    DEFF Research Database (Denmark)

    Ionescu, Irina Alexandra; Møller, Birger Lindberg; Sánchez Pérez, Raquel

    2017-01-01

    Flowering at the right time is of great importance; it secures seed production and therefore species survival and crop yield. In addition to the genetic network controlling flowering time, there are a number of much less studied metabolites and exogenously applied chemicals that may influence...... on the genetic aspects of flowering time regulation in annuals, but less so in perennials. An alternative to plant breeding approaches is to engineer flowering time chemically via the external application of flower-inducing compounds. This review discusses a variety of exogenously applied compounds used in fruit...

  17. Time Perception and Psychiatric Disorders

    Directory of Open Access Journals (Sweden)

    Hatice Ceviz

    2013-09-01

    Full Text Available Time perception is an ability which we use in every moment of daily life, that guides the formation and continuation of our behaviors and from an evolutionary perspective ensures survival. Internal clock models help us to understand time perception. Time perception is known to vary between individuals and particular situations. This variability is explained with the mechanisms which is associated with the processes related to attention, the speed of the internal clock and the memory unit. It is suggested that time perception is mainly associated with the activities of dopamine and acetylcholine. Some dopaminergic psychoactive substances like cocaine and amphetamine have all been shown to change time perception by increasing the speed of internal clock while on the other hand some antipsychotic drugs make an opposite change in time perception by descreasing the speed of the clock. Similarly, time perception is affected in some psychiatric disorders and an ethiopathological relationship between time perception disturbances and psychiatric disorders is suggested. In this article time perception changes in schizophrenia, attention deficit/hyperactivity syndrome, depression, anxiety disorders and personality disorders are briefly reviewed.

  18. Timed bisimulation and open maps

    DEFF Research Database (Denmark)

    Hune, Thomas; Nielsen, Mogens

    1998-01-01

    of timed bisimulation. Thus the abstract results from the theory of open maps apply, e.g. the existence of canonical models and characteristic logics. Here, we provide an alternative proof of decidability of bisimulation for finite timed transition systems in terms of open maps, and illustrate the use......Open maps have been used for defining bisimulations for a range of models, but none of these have modelled real-time. We define a category of timed transition systems, and use the general framework of open maps to obtain a notion of bisimulation. We show this to be equivalent to the standard notion...... of open maps in presenting bisimulations....

  19. Dependable Real-Time Systems

    Science.gov (United States)

    1991-09-30

    0196 or 413 545-0720 PI E-mail Address: krithi@nirvan.cs.umass.edu, stankovic(ocs.umass.edu Grant or Contract Title: Dependable Real - Time Systems Grant...Dependable Real - Time Systems " Grant or Contract Number: N00014-85-k-0398 L " Reporting Period: 1 Oct 87 - 30 Sep 91 , 2. Summary of Accomplishments ’ 2.1 Our...in developing a sound approach to scheduling tasks in complex real - time systems , (2) developed a real-time operating system kernel, a preliminary

  20. CBP Time and Attendance Management

    Data.gov (United States)

    Department of Homeland Security — The TAMS, supports time and attendance (payroll), overtime cap monitoring, overtime scheduling functions, budget reporting, staffing level reporting, and a variety...