WorldWideScience

Sample records for integration time intervals

  1. A model of interval timing by neural integration.

    Science.gov (United States)

    Simen, Patrick; Balci, Fuat; de Souza, Laura; Cohen, Jonathan D; Holmes, Philip

    2011-06-22

    We show that simple assumptions about neural processing lead to a model of interval timing as a temporal integration process, in which a noisy firing-rate representation of time rises linearly on average toward a response threshold over the course of an interval. Our assumptions include: that neural spike trains are approximately independent Poisson processes, that correlations among them can be largely cancelled by balancing excitation and inhibition, that neural populations can act as integrators, and that the objective of timed behavior is maximal accuracy and minimal variance. The model accounts for a variety of physiological and behavioral findings in rodents, monkeys, and humans, including ramping firing rates between the onset of reward-predicting cues and the receipt of delayed rewards, and universally scale-invariant response time distributions in interval timing tasks. It furthermore makes specific, well-supported predictions about the skewness of these distributions, a feature of timing data that is usually ignored. The model also incorporates a rapid (potentially one-shot) duration-learning procedure. Human behavioral data support the learning rule's predictions regarding learning speed in sequences of timed responses. These results suggest that simple, integration-based models should play as prominent a role in interval timing theory as they do in theories of perceptual decision making, and that a common neural mechanism may underlie both types of behavior.

  2. Hybrid integrated circuit for charge-to-time interval conversion

    Energy Technology Data Exchange (ETDEWEB)

    Basiladze, S.G.; Dotsenko, Yu.Yu.; Man' yakov, P.K.; Fedorchenko, S.N. (Joint Inst. for Nuclear Research, Dubna (USSR))

    The hybrid integrated circuit for charge-to time interval conversion with nanosecond input fast response is described. The circuit can be used in energy measuring channels, time-to-digital converters and in the modified variant in amplitude-to-digital converters. The converter described consists of a buffer amplifier, a linear transmission circuit, a direct current source and a unit of time interval separation. The buffer amplifier represents a current follower providing low input and high output resistances by the current feedback. It is concluded that the described converter excelled the QT100B circuit analogous to it in a number of parameters especially, in thermostability.

  3. An integrated theory of prospective time interval estimation : The role of cognition, attention, and learning

    NARCIS (Netherlands)

    Taatgen, Niels A.; van Rijn, Hedderik; Anderson, John

    A theory of prospective time perception is introduced and incorporated as a module in an integrated theory of cognition, thereby extending existing theories and allowing predictions about attention and learning. First, a time perception module is established by fitting existing datasets (interval

  4. An Integrated Theory of Prospective Time Interval Estimation: The Role of Cognition, Attention, and Learning

    Science.gov (United States)

    Taatgen, Niels A.; van Rijn, Hedderik; Anderson, John

    2007-01-01

    A theory of prospective time perception is introduced and incorporated as a module in an integrated theory of cognition, thereby extending existing theories and allowing predictions about attention and learning. First, a time perception module is established by fitting existing datasets (interval estimation and bisection and impact of secondary…

  5. Time-interval for integration of stabilizing haptic and visual information in subjects balancing under static and dynamic conditions

    Directory of Open Access Journals (Sweden)

    Jean-Louis eHoneine

    2014-10-01

    Full Text Available Maintaining equilibrium is basically a sensorimotor integration task. The central nervous system continually and selectively weights and rapidly integrates sensory inputs from multiple sources, and coordinates multiple outputs. The weighting process is based on the availability and accuracy of afferent signals at a given instant, on the time-period required to process each input, and possibly on the plasticity of the relevant pathways. The likelihood that sensory inflow changes while balancing under static or dynamic conditions is high, because subjects can pass from a dark to a well-lit environment or from a tactile-guided stabilization to loss of haptic inflow. This review article presents recent data on the temporal events accompanying sensory transition, on which basic information is fragmentary. The processing time from sensory shift to reaching a new steady state includes the time to (a subtract or integrate sensory inputs, (b move from allocentric to egocentric reference or vice versa, and (c adjust the calibration of motor activity in time and amplitude to the new sensory set. We present examples of processes of integration of posture-stabilizing information, and of the respective sensorimotor time-intervals while allowing or occluding vision or adding or subtracting tactile information. These intervals are short, in the order of 1-2 s for different postural conditions, modalities and deliberate or passive shift. They are just longer for haptic than visual shift, just shorter on withdrawal than on addition of stabilizing input, and on deliberate than unexpected mode. The delays are the shortest (for haptic shift in blind subjects. Since automatic balance stabilization may be vulnerable to sensory-integration delays and to interference from concurrent cognitive tasks in patients with sensorimotor problems, insight into the processing time for balance control represents a critical step in the design of new balance- and locomotion training

  6. Time-interval for integration of stabilizing haptic and visual information in subjects balancing under static and dynamic conditions

    Science.gov (United States)

    Honeine, Jean-Louis; Schieppati, Marco

    2014-01-01

    Maintaining equilibrium is basically a sensorimotor integration task. The central nervous system (CNS) continually and selectively weights and rapidly integrates sensory inputs from multiple sources, and coordinates multiple outputs. The weighting process is based on the availability and accuracy of afferent signals at a given instant, on the time-period required to process each input, and possibly on the plasticity of the relevant pathways. The likelihood that sensory inflow changes while balancing under static or dynamic conditions is high, because subjects can pass from a dark to a well-lit environment or from a tactile-guided stabilization to loss of haptic inflow. This review article presents recent data on the temporal events accompanying sensory transition, on which basic information is fragmentary. The processing time from sensory shift to reaching a new steady state includes the time to (a) subtract or integrate sensory inputs; (b) move from allocentric to egocentric reference or vice versa; and (c) adjust the calibration of motor activity in time and amplitude to the new sensory set. We present examples of processes of integration of posture-stabilizing information, and of the respective sensorimotor time-intervals while allowing or occluding vision or adding or subtracting tactile information. These intervals are short, in the order of 1–2 s for different postural conditions, modalities and deliberate or passive shift. They are just longer for haptic than visual shift, just shorter on withdrawal than on addition of stabilizing input, and on deliberate than unexpected mode. The delays are the shortest (for haptic shift) in blind subjects. Since automatic balance stabilization may be vulnerable to sensory-integration delays and to interference from concurrent cognitive tasks in patients with sensorimotor problems, insight into the processing time for balance control represents a critical step in the design of new balance- and locomotion training devices

  7. Finite-Time Stability of Large-Scale Systems with Interval Time-Varying Delay in Interconnection

    Directory of Open Access Journals (Sweden)

    T. La-inchua

    2017-01-01

    Full Text Available We investigate finite-time stability of a class of nonlinear large-scale systems with interval time-varying delays in interconnection. Time-delay functions are continuous but not necessarily differentiable. Based on Lyapunov stability theory and new integral bounding technique, finite-time stability of large-scale systems with interval time-varying delays in interconnection is derived. The finite-time stability criteria are delays-dependent and are given in terms of linear matrix inequalities which can be solved by various available algorithms. Numerical examples are given to illustrate effectiveness of the proposed method.

  8. Symbol lock detection implemented with nonoverlapping integration intervals

    Science.gov (United States)

    Shihabi, Mazen M. (Inventor); Hinedi, Sami M. (Inventor); Shah, Biren N. (Inventor)

    1995-01-01

    A symbol lock detector is introduced for an incoming coherent digital communication signal which utilizes a subcarrier modulated with binary symbol data, d(sub k), and known symbol interval T by integrating binary values of the signal over nonoverlapping first and second intervals selected to be T/2, delaying the first integral an interval T/2, and either summing or multiplying the second integral with the first one that preceded it to form a value X(sub k). That value is then averaged over a number M of symbol intervals to produce a static value Y. A symbol lock decision can then be made when the static value Y exceeds a threshold level delta.

  9. New precession expressions, valid for long time intervals

    Science.gov (United States)

    Vondrák, J.; Capitaine, N.; Wallace, P.

    2011-10-01

    Context. The present IAU model of precession, like its predecessors, is given as a set of polynomial approximations of various precession parameters intended for high-accuracy applications over a limited time span. Earlier comparisons with numerical integrations have shown that this model is valid only for a few centuries around the basic epoch, J2000.0, while for more distant epochs it rapidly diverges from the numerical solution. In our preceding studies we also obtained preliminary developments for the precessional contribution to the motion of the equator: coordinates X,Y of the precessing pole and precession parameters ψA,ωA, suitable for use over long time intervals. Aims: The goal of the present paper is to obtain upgraded developments for various sets of precession angles that would fit modern observations near J2000.0 and at the same time fit numerical integration of the motions of solar system bodies on scales of several thousand centuries. Methods: We used the IAU 2006 solutions to represent the precession of the ecliptic and of the equator close to J2000.0 and, for more distant epochs, a numerical integration using the Mercury 6 package and solutions by Laskar et al. (1993, A&A, 270, 522) with upgraded initial conditions and constants to represent the ecliptic, and general precession and obliquity, respectively. From them, different precession parameters were calculated in the interval ± 200 millennia from J2000.0, and analytical expressions are found that provide a good fit for the whole interval. Results: Series for the various precessional parameters, comprising a cubic polynomial plus from 8 to 14 periodic terms, are derived that allow precession to be computed with an accuracy comparable to IAU 2006 around the central epoch J2000.0, a few arcseconds throughout the historical period, and a few tenths of a degree at the ends of the ± 200 millennia time span. Computer algorithms are provided that compute the ecliptic and mean equator poles and the

  10. 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.

  11. Internal representations of temporal statistics and feedback calibrate motor-sensory interval timing.

    Directory of Open Access Journals (Sweden)

    Luigi Acerbi

    Full Text Available Humans have been shown to adapt to the temporal statistics of timing tasks so as to optimize the accuracy of their responses, in agreement with the predictions of Bayesian integration. This suggests that they build an internal representation of both the experimentally imposed distribution of time intervals (the prior and of the error (the loss function. The responses of a Bayesian ideal observer depend crucially on these internal representations, which have only been previously studied for simple distributions. To study the nature of these representations we asked subjects to reproduce time intervals drawn from underlying temporal distributions of varying complexity, from uniform to highly skewed or bimodal while also varying the error mapping that determined the performance feedback. Interval reproduction times were affected by both the distribution and feedback, in good agreement with a performance-optimizing Bayesian observer and actor model. Bayesian model comparison highlighted that subjects were integrating the provided feedback and represented the experimental distribution with a smoothed approximation. A nonparametric reconstruction of the subjective priors from the data shows that they are generally in agreement with the true distributions up to third-order moments, but with systematically heavier tails. In particular, higher-order statistical features (kurtosis, multimodality seem much harder to acquire. Our findings suggest that humans have only minor constraints on learning lower-order statistical properties of unimodal (including peaked and skewed distributions of time intervals under the guidance of corrective feedback, and that their behavior is well explained by Bayesian decision theory.

  12. Intact interval timing in circadian CLOCK mutants.

    Science.gov (United States)

    Cordes, Sara; Gallistel, C R

    2008-08-28

    While progress has been made in determining the molecular basis for the circadian clock, the mechanism by which mammalian brains time intervals measured in seconds to minutes remains a mystery. An obvious question is whether the interval-timing mechanism shares molecular machinery with the circadian timing mechanism. In the current study, we trained circadian CLOCK +/- and -/- mutant male mice in a peak-interval procedure with 10 and 20-s criteria. The mutant mice were more active than their wild-type littermates, but there were no reliable deficits in the accuracy or precision of their timing as compared with wild-type littermates. This suggests that expression of the CLOCK protein is not necessary for normal interval timing.

  13. Department of Defense Precise Time and Time Interval program improvement plan

    Science.gov (United States)

    Bowser, J. R.

    1981-01-01

    The United States Naval Observatory is responsible for ensuring uniformity in precise time and time interval operations including measurements, the establishment of overall DOD requirements for time and time interval, and the accomplishment of objectives requiring precise time and time interval with minimum cost. An overview of the objectives, the approach to the problem, the schedule, and a status report, including significant findings relative to organizational relationships, current directives, principal PTTI users, and future requirements as currently identified by the users are presented.

  14. Time-to-code converter with selection of time intervals on duration

    International Nuclear Information System (INIS)

    Atanasov, I.Kh.; Rusanov, I.R.; )

    2001-01-01

    Identification of elementary particles on the basis of time-of-flight represents the important approach of the preliminary selection procedure. Paper describes a time-to-code converter with preliminary selection of the measured time intervals as to duration. It consists of a time-to-amplitude converter, an analog-to-digital converter, a unit of selection of time intervals as to duration, a unit of total reset and CAMAC command decoder. The time-to-code converter enables to measure time intervals with 100 ns accuracy within 0-100 ns range. Output code capacity is of 10. Selection time constitutes 50 ns [ru

  15. H∞ state estimation of generalised neural networks with interval time-varying delays

    Science.gov (United States)

    Saravanakumar, R.; Syed Ali, M.; Cao, Jinde; Huang, He

    2016-12-01

    This paper focuses on studying the H∞ state estimation of generalised neural networks with interval time-varying delays. The integral terms in the time derivative of the Lyapunov-Krasovskii functional are handled by the Jensen's inequality, reciprocally convex combination approach and a new Wirtinger-based double integral inequality. A delay-dependent criterion is derived under which the estimation error system is globally asymptotically stable with H∞ performance. The proposed conditions are represented by linear matrix inequalities. Optimal H∞ norm bounds are obtained easily by solving convex problems in terms of linear matrix inequalities. The advantage of employing the proposed inequalities is illustrated by numerical examples.

  16. Continuous time modelling with individually varying time intervals for oscillating and non-oscillating processes.

    Science.gov (United States)

    Voelkle, Manuel C; Oud, Johan H L

    2013-02-01

    When designing longitudinal studies, researchers often aim at equal intervals. In practice, however, this goal is hardly ever met, with different time intervals between assessment waves and different time intervals between individuals being more the rule than the exception. One of the reasons for the introduction of continuous time models by means of structural equation modelling has been to deal with irregularly spaced assessment waves (e.g., Oud & Delsing, 2010). In the present paper we extend the approach to individually varying time intervals for oscillating and non-oscillating processes. In addition, we show not only that equal intervals are unnecessary but also that it can be advantageous to use unequal sampling intervals, in particular when the sampling rate is low. Two examples are provided to support our arguments. In the first example we compare a continuous time model of a bivariate coupled process with varying time intervals to a standard discrete time model to illustrate the importance of accounting for the exact time intervals. In the second example the effect of different sampling intervals on estimating a damped linear oscillator is investigated by means of a Monte Carlo simulation. We conclude that it is important to account for individually varying time intervals, and encourage researchers to conceive of longitudinal studies with different time intervals within and between individuals as an opportunity rather than a problem. © 2012 The British Psychological Society.

  17. Note on the Choquet Integral as an Interval-Valued Aggregation Operators and Their Applications

    Directory of Open Access Journals (Sweden)

    Lee-Chae Jang

    2012-01-01

    Full Text Available The concept of an interval-valued capacity is motivated by the goal to generalize a capacity, and it can be used for representing an uncertain capacity. In this paper, we define the discrete interval-valued capacities, a measure of the entropy of a discrete interval-valued capacity, and, Choquet integral with respect to a discrete interval-valued capacity. In particular, we discuss the Choquet integral as an interval-valued aggregation operator and discuss an application of them.

  18. Integral equations with difference kernels on finite intervals

    CERN Document Server

    Sakhnovich, Lev A

    2015-01-01

    This book focuses on solving integral equations with difference kernels on finite intervals. The corresponding problem on the semiaxis was previously solved by N. Wiener–E. Hopf and by M.G. Krein. The problem on finite intervals, though significantly more difficult, may be solved using our method of operator identities. This method is also actively employed in inverse spectral problems, operator factorization and nonlinear integral equations. Applications of the obtained results to optimal synthesis, light scattering, diffraction, and hydrodynamics problems are discussed in this book, which also describes how the theory of operators with difference kernels is applied to stable processes and used to solve the famous M. Kac problems on stable processes. In this second edition these results are extensively generalized and include the case of all Levy processes. We present the convolution expression for the well-known Ito formula of the generator operator, a convolution expression that has proven to be fruitful...

  19. A New Approach to Interval-Valued Choquet Integrals and the Problem of Ordering in Interval-Valued Fuzzy Set Applications

    Czech Academy of Sciences Publication Activity Database

    Bustince, H.; Galar, M.; Bedregal, B.; Kolesárová, A.; Mesiar, Radko

    2013-01-01

    Roč. 21, č. 6 (2013), s. 1150-1162 ISSN 1063-6706 R&D Projects: GA ČR GAP402/11/0378 Institutional support: RVO:67985556 Keywords : Interval- value d Choquet integral * Shapley value * interval- value d ordered weighted aggregation (OWA) operators * interval- value d decision making Subject RIV: BA - General Mathematics Impact factor: 6.306, year: 2013 http://library.utia.cas.cz/separaty/2013/E/mesiar-0399771.pdf

  20. Delay-Dependent Guaranteed Cost Control of an Interval System with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Xiao Min

    2009-01-01

    Full Text Available This paper concerns the problem of the delay-dependent robust stability and guaranteed cost control for an interval system with time-varying delay. The interval system with matrix factorization is provided and leads to less conservative conclusions than solving a square root. The time-varying delay is assumed to belong to an interval and the derivative of the interval time-varying delay is not a restriction, which allows a fast time-varying delay; also its applicability is broad. Based on the Lyapunov-Ktasovskii approach, a delay-dependent criterion for the existence of a state feedback controller, which guarantees the closed-loop system stability, the upper bound of cost function, and disturbance attenuation lever for all admissible uncertainties as well as out perturbation, is proposed in terms of linear matrix inequalities (LMIs. The criterion is derived by free weighting matrices that can reduce the conservatism. The effectiveness has been verified in a number example and the compute results are presented to validate the proposed design method.

  1. Reviewing interval cancers: Time well spent?

    International Nuclear Information System (INIS)

    Gower-Thomas, Kate; Fielder, Hilary M.P.; Branston, Lucy; Greening, Sarah; Beer, Helen; Rogers, Cerilan

    2002-01-01

    OBJECTIVES: To categorize interval cancers, and thus identify false-negatives, following prevalent and incident screens in the Welsh breast screening programme. SETTING: Breast Test Wales (BTW) Llandudno, Cardiff and Swansea breast screening units. METHODS: Five hundred and sixty interval breast cancers identified following negative mammographic screening between 1989 and 1997 were reviewed by eight screening radiologists. The blind review was achieved by mixing the screening films of women who subsequently developed an interval cancer with screen negative films of women who did not develop cancer, in a ratio of 4:1. Another radiologist used patients' symptomatic films to record a reference against which the reviewers' reports of the screening films were compared. Interval cancers were categorized as 'true', 'occult', 'false-negative' or 'unclassified' interval cancers or interval cancers with minimal signs, based on the National Health Service breast screening programme (NHSBSP) guidelines. RESULTS: Of the classifiable interval films, 32% were false-negatives, 55% were true intervals and 12% occult. The proportion of false-negatives following incident screens was half that following prevalent screens (P = 0.004). Forty percent of the seed films were recalled by the panel. CONCLUSIONS: Low false-negative interval cancer rates following incident screens (18%) versus prevalent screens (36%) suggest that lower cancer detection rates at incident screens may have resulted from fewer cancers than expected being present, rather than from a failure to detect tumours. The panel method for categorizing interval cancers has significant flaws as the results vary markedly with different protocol and is no more accurate than other, quicker and more timely methods. Gower-Thomas, K. et al. (2002)

  2. Robust stability analysis for Markovian jumping interval neural networks with discrete and distributed time-varying delays

    International Nuclear Information System (INIS)

    Balasubramaniam, P.; Lakshmanan, S.; Manivannan, A.

    2012-01-01

    Highlights: ► Robust stability analysis for Markovian jumping interval neural networks is considered. ► Both linear fractional and interval uncertainties are considered. ► A new LKF is constructed with triple integral terms. ► MATLAB LMI control toolbox is used to validate theoretical results. ► Numerical examples are given to illustrate the effectiveness of the proposed method. - Abstract: This paper investigates robust stability analysis for Markovian jumping interval neural networks with discrete and distributed time-varying delays. The parameter uncertainties are assumed to be bounded in given compact sets. The delay is assumed to be time-varying and belong to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. Based on the new Lyapunov–Krasovskii functional (LKF), some inequality techniques and stochastic stability theory, new delay-dependent stability criteria have been obtained in terms of linear matrix inequalities (LMIs). Finally, two numerical examples are given to illustrate the less conservative and effectiveness of our theoretical results.

  3. Interval timing in genetically modified mice: a simple paradigm

    OpenAIRE

    Balci, F.; Papachristos, E. B.; Gallistel, C. R.; Brunner, D.; Gibson, J.; Shumyatsky, G. P.

    2007-01-01

    We describe a behavioral screen for the quantitative study of interval timing and interval memory in mice. Mice learn to switch from a short-latency feeding station to a long-latency station when the short latency has passed without a feeding. The psychometric function is the cumulative distribution of switch latencies. Its median measures timing accuracy and its interquartile interval measures timing precision. Next, using this behavioral paradigm, we have examined mice with a gene knockout ...

  4. Time interval approach to the pulsed neutron logging method

    International Nuclear Information System (INIS)

    Zhao Jingwu; Su Weining

    1994-01-01

    The time interval of neighbouring neutrons emitted from a steady state neutron source can be treated as that from a time-dependent neutron source. In the rock space, the neutron flux is given by the neutron diffusion equation and is composed of an infinite terms. Each term s composed of two die-away curves. The delay action is discussed and used to measure the time interval with only one detector in the experiment. Nuclear reactions with the time distribution due to different types of radiations observed in the neutron well-logging methods are presented with a view to getting the rock nuclear parameters from the time interval technique

  5. Delay-Dependent Guaranteed Cost H∞ Control of an Interval System with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Zhongke Shi

    2009-01-01

    Full Text Available This paper concerns the problem of the delay-dependent robust stability and guaranteed cost H∞ control for an interval system with time-varying delay. The interval system with matrix factorization is provided and leads to less conservative conclusions than solving a square root. The time-varying delay is assumed to belong to an interval and the derivative of the interval time-varying delay is not a restriction, which allows a fast time-varying delay; also its applicability is broad. Based on the Lyapunov-Ktasovskii approach, a delay-dependent criterion for the existence of a state feedback controller, which guarantees the closed-loop system stability, the upper bound of cost function, and disturbance attenuation lever for all admissible uncertainties as well as out perturbation, is proposed in terms of linear matrix inequalities (LMIs. The criterion is derived by free weighting matrices that can reduce the conservatism. The effectiveness has been verified in a number example and the compute results are presented to validate the proposed design method.

  6. An integral equation approach to the interval reliability of systems modelled by finite semi-Markov processes

    International Nuclear Information System (INIS)

    Csenki, A.

    1995-01-01

    The interval reliability for a repairable system which alternates between working and repair periods is defined as the probability of the system being functional throughout a given time interval. In this paper, a set of integral equations is derived for this dependability measure, under the assumption that the system is modelled by an irreducible finite semi-Markov process. The result is applied to the semi-Markov model of a two-unit system with sequential preventive maintenance. The method used for the numerical solution of the resulting system of integral equations is a two-point trapezoidal rule. The system of implementation is the matrix computation package MATLAB on the Apple Macintosh SE/30. The numerical results are discussed and compared with those from simulation

  7. Discrete-time optimal control and games on large intervals

    CERN Document Server

    Zaslavski, Alexander J

    2017-01-01

    Devoted to the structure of approximate solutions of discrete-time optimal control problems and approximate solutions of dynamic discrete-time two-player zero-sum games, this book presents results on properties of approximate solutions in an interval that is independent lengthwise, for all sufficiently large intervals. Results concerning the so-called turnpike property of optimal control problems and zero-sum games in the regions close to the endpoints of the time intervals are the main focus of this book. The description of the structure of approximate solutions on sufficiently large intervals and its stability will interest graduate students and mathematicians in optimal control and game theory, engineering, and economics. This book begins with a brief overview and moves on to analyze the structure of approximate solutions of autonomous nonconcave discrete-time optimal control Lagrange problems.Next the structures of approximate solutions of autonomous discrete-time optimal control problems that are discret...

  8. Specifying real-time systems with interval logic

    Science.gov (United States)

    Rushby, John

    1988-01-01

    Pure temporal logic makes no reference to time. An interval temporal logic and an extension to that logic which includes real time constraints are described. The application of this logic by giving a specification for the well-known lift (elevator) example is demonstrated. It is shown how interval logic can be extended to include a notion of process. How the specification language and verification environment of EHDM could be enhanced to support this logic is described. A specification of the alternating bit protocol in this extended version of the specification language of EHDM is given.

  9. Impact of Vestibular Lesions on Allocentric Navigation and Interval Timing: The Role of Self-Initiated Motion in Spatial-Temporal Integration

    Czech Academy of Sciences Publication Activity Database

    Dallal, N. L.; Yin, B.; Nekovářová, Tereza; Stuchlík, Aleš; Meck, W. H.

    2015-01-01

    Roč. 3, 3-4 (2015), s. 269-305 ISSN 2213-445X R&D Projects: GA MŠk(CZ) LH14053 Institutional support: RVO:67985823 Keywords : peak-interval procedure * interval timing * radial-arm maze * magnitude representation * dorsolateral striatum * self-initiated movement * hippocampus * cerebellum * time perception * allocentric navigation Subject RIV: FH - Neurology

  10. Unpacking a time interval lengthens its perceived temporal distance

    Directory of Open Access Journals (Sweden)

    Yang eLiu

    2014-11-01

    Full Text Available In quantity estimation, people often perceive that the whole is less than the sum of its parts. The current study investigated such an unpacking effect in temporal distance judgment. Our results showed that participants in the unpacked condition judged a given time interval longer than those in the packed condition, even the time interval was kept constant between the two conditions. Furthermore, this unpacking effect persists regardless of the unpacking ways we employed. Results suggest that unpacking a time interval may be a good strategy for lengthening its perceived temporal distance.

  11. Effects of integration time on in-water radiometric profiles.

    Science.gov (United States)

    D'Alimonte, Davide; Zibordi, Giuseppe; Kajiyama, Tamito

    2018-03-05

    This work investigates the effects of integration time on in-water downward irradiance E d , upward irradiance E u and upwelling radiance L u profile data acquired with free-fall hyperspectral systems. Analyzed quantities are the subsurface value and the diffuse attenuation coefficient derived by applying linear and non-linear regression schemes. Case studies include oligotrophic waters (Case-1), as well as waters dominated by Colored Dissolved Organic Matter (CDOM) and Non-Algal Particles (NAP). Assuming a 24-bit digitization, measurements resulting from the accumulation of photons over integration times varying between 8 and 2048ms are evaluated at depths corresponding to: 1) the beginning of each integration interval (Fst); 2) the end of each integration interval (Lst); 3) the averages of Fst and Lst values (Avg); and finally 4) the values weighted accounting for the diffuse attenuation coefficient of water (Wgt). Statistical figures show that the effects of integration time can bias results well above 5% as a function of the depth definition. Results indicate the validity of the Wgt depth definition and the fair applicability of the Avg one. Instead, both the Fst and Lst depths should not be adopted since they may introduce pronounced biases in E u and L u regression products for highly absorbing waters. Finally, the study reconfirms the relevance of combining multiple radiometric casts into a single profile to increase precision of regression products.

  12. Traces of times past : Representations of temporal intervals in memory

    NARCIS (Netherlands)

    Taatgen, Niels; van Rijn, Hedderik

    2011-01-01

    Theories of time perception typically assume that some sort of memory represents time intervals. This memory component is typically underdeveloped in theories of time perception. Following earlier work that suggested that representations of different time intervals contaminate each other (Grondin,

  13. Learned Interval Time Facilitates Associate Memory Retrieval

    Science.gov (United States)

    van de Ven, Vincent; Kochs, Sarah; Smulders, Fren; De Weerd, Peter

    2017-01-01

    The extent to which time is represented in memory remains underinvestigated. We designed a time paired associate task (TPAT) in which participants implicitly learned cue-time-target associations between cue-target pairs and specific cue-target intervals. During subsequent memory testing, participants showed increased accuracy of identifying…

  14. Interval-Censored Time-to-Event Data Methods and Applications

    CERN Document Server

    Chen, Ding-Geng

    2012-01-01

    Interval-Censored Time-to-Event Data: Methods and Applications collects the most recent techniques, models, and computational tools for interval-censored time-to-event data. Top biostatisticians from academia, biopharmaceutical industries, and government agencies discuss how these advances are impacting clinical trials and biomedical research. Divided into three parts, the book begins with an overview of interval-censored data modeling, including nonparametric estimation, survival functions, regression analysis, multivariate data analysis, competing risks analysis, and other models for interva

  15. Early diastolic time intervals during hypertensive pregnancy.

    Science.gov (United States)

    Spinelli, L; Ferro, G; Nappi, C; Farace, M J; Talarico, G; Cinquegrana, G; Condorelli, M

    1987-10-01

    Early diastolic time intervals have been assessed by means of the echopolycardiographic method in 17 pregnant women who developed hypertension during pregnancy (HP) and in 14 normal pregnant women (N). Systolic time intervals (STI), stroke volume (SV), ejection fraction (EF), and mean velocity of myocardial fiber shortening (VCF) were also evaluated. Recordings were performed in the left lateral decubitus (LLD) and then in the supine decubitus (SD). In LLD, isovolumic relaxation period (IRP) was prolonged in the hypertensive pregnant women compared with normal pregnant women (HP 51 +/- 12.5 ms, N 32.4 +/- 15 ms p less than 0.05), whereas time of the mitral valve maximum opening (DE) was not different in the groups. There was no difference in SV, EF, and mean VCF, whereas STI showed only a significant (p less than 0.05) lengthening of pre-ejection period (PEP) in HP. When the subjects shifted from the left lateral to the supine decubitus position, left ventricular ejection time index (LVETi) and SV decreased significantly (p less than 0.05) in both normotensive hypertensive pregnant women. IRP and PEP lengthened significantly (p less than 0.05) only in normals, whereas they were unchanged in HP. DE time did not vary in either group. In conclusion, hypertension superimposed on pregnancy induces lengthening of IRP, as well as of PEP, and minimizes the effects of the postural changes in preload on the above-mentioned time intervals.

  16. Individual Case Analysis of Postmortem Interval Time on Brain Tissue Preservation.

    Directory of Open Access Journals (Sweden)

    Jeffrey A Blair

    Full Text Available At autopsy, the time that has elapsed since the time of death is routinely documented and noted as the postmortem interval (PMI. The PMI of human tissue samples is a parameter often reported in research studies and comparable PMI is preferred when comparing different populations, i.e., disease versus control patients. In theory, a short PMI may alleviate non-experimental protein denaturation, enzyme activity, and other chemical changes such as the pH, which could affect protein and nucleic acid integrity. Previous studies have compared PMI en masse by looking at many different individual cases each with one unique PMI, which may be affected by individual variance. To overcome this obstacle, in this study human hippocampal segments from the same individuals were sampled at different time points after autopsy creating a series of PMIs for each case. Frozen and fixed tissue was then examined by Western blot, RT-PCR, and immunohistochemistry to evaluate the effect of extended PMI on proteins, nucleic acids, and tissue morphology. In our results, immunostaining profiles for most proteins remained unchanged even after PMI of over 50 h, yet by Western blot distinctive degradation patterns were observed in different protein species. Finally, RNA integrity was lower after extended PMI; however, RNA preservation was variable among cases suggesting antemortem factors may play a larger role than PMI in protein and nucleic acid integrity.

  17. Timing of multiple overlapping intervals : How many clocks do we have?

    NARCIS (Netherlands)

    van Rijn, Hedderik; Taatgen, Niels A.

    2008-01-01

    Humans perceive and reproduce short intervals of time (e.g. 1-60 s) relatively accurately, and are capable of timing multiple overlapping intervals if these intervals are presented in different modalities [e.g., Rousseau, L., & Rousseau, RL (1996). Stop-reaction time and the internal clock.

  18. The Time Is Up: Compression of Visual Time Interval Estimations of Bimodal Aperiodic Patterns

    Science.gov (United States)

    Duarte, Fabiola; Lemus, Luis

    2017-01-01

    The ability to estimate time intervals subserves many of our behaviors and perceptual experiences. However, it is not clear how aperiodic (AP) stimuli affect our perception of time intervals across sensory modalities. To address this question, we evaluated the human capacity to discriminate between two acoustic (A), visual (V) or audiovisual (AV) time intervals of trains of scattered pulses. We first measured the periodicity of those stimuli and then sought for correlations with the accuracy and reaction times (RTs) of the subjects. We found that, for all time intervals tested in our experiment, the visual system consistently perceived AP stimuli as being shorter than the periodic (P) ones. In contrast, such a compression phenomenon was not apparent during auditory trials. Our conclusions are: first, the subjects exposed to P stimuli are more likely to measure their durations accurately. Second, perceptual time compression occurs for AP visual stimuli. Lastly, AV discriminations are determined by A dominance rather than by AV enhancement. PMID:28848406

  19. Monitoring molecular interactions using photon arrival-time interval distribution analysis

    Science.gov (United States)

    Laurence, Ted A [Livermore, CA; Weiss, Shimon [Los Angels, CA

    2009-10-06

    A method for analyzing/monitoring the properties of species that are labeled with fluorophores. A detector is used to detect photons emitted from species that are labeled with one or more fluorophores and located in a confocal detection volume. The arrival time of each of the photons is determined. The interval of time between various photon pairs is then determined to provide photon pair intervals. The number of photons that have arrival times within the photon pair intervals is also determined. The photon pair intervals are then used in combination with the corresponding counts of intervening photons to analyze properties and interactions of the molecules including brightness, concentration, coincidence and transit time. The method can be used for analyzing single photon streams and multiple photon streams.

  20. Interval timing in genetically modified mice: a simple paradigm.

    Science.gov (United States)

    Balci, F; Papachristos, E B; Gallistel, C R; Brunner, D; Gibson, J; Shumyatsky, G P

    2008-04-01

    We describe a behavioral screen for the quantitative study of interval timing and interval memory in mice. Mice learn to switch from a short-latency feeding station to a long-latency station when the short latency has passed without a feeding. The psychometric function is the cumulative distribution of switch latencies. Its median measures timing accuracy and its interquartile interval measures timing precision. Next, using this behavioral paradigm, we have examined mice with a gene knockout of the receptor for gastrin-releasing peptide that show enhanced (i.e. prolonged) freezing in fear conditioning. We have tested the hypothesis that the mutants freeze longer because they are more uncertain than wild types about when to expect the electric shock. The knockouts however show normal accuracy and precision in timing, so we have rejected this alternative hypothesis. Last, we conduct the pharmacological validation of our behavioral screen using d-amphetamine and methamphetamine. We suggest including the analysis of interval timing and temporal memory in tests of genetically modified mice for learning and memory and argue that our paradigm allows this to be done simply and efficiently.

  1. Ratio-based lengths of intervals to improve fuzzy time series forecasting.

    Science.gov (United States)

    Huarng, Kunhuang; Yu, Tiffany Hui-Kuang

    2006-04-01

    The objective of this study is to explore ways of determining the useful lengths of intervals in fuzzy time series. It is suggested that ratios, instead of equal lengths of intervals, can more properly represent the intervals among observations. Ratio-based lengths of intervals are, therefore, proposed to improve fuzzy time series forecasting. Algebraic growth data, such as enrollments and the stock index, and exponential growth data, such as inventory demand, are chosen as the forecasting targets, before forecasting based on the various lengths of intervals is performed. Furthermore, sensitivity analyses are also carried out for various percentiles. The ratio-based lengths of intervals are found to outperform the effective lengths of intervals, as well as the arbitrary ones in regard to the different statistical measures. The empirical analysis suggests that the ratio-based lengths of intervals can also be used to improve fuzzy time series forecasting.

  2. Terminal current interpolation for multirate time integration of hierarchical IC models

    NARCIS (Netherlands)

    Verhoeven, A.; Maten, ter E.J.W.; Dohmen, J.J.; Tasic, B.; Mattheij, R.M.M.; Fitt, A.D.; Norbury, J.; Ockendon, H.; Wilson, E.

    2010-01-01

    Multirate time-integration methods [3–5] appear to be attractive for initial value problems for DAEs with latency or multirate behaviour. Latency means that parts of the circuit are constant or slowly time-varying during a certain time interval, while multirate behaviour means that some variables

  3. CMOS direct time interval measurement of long-lived luminescence lifetimes.

    Science.gov (United States)

    Yao, Lei; Yung, Ka Yi; Cheung, Maurice C; Chodavarapu, Vamsy P; Bright, Frank V

    2011-01-01

    We describe a Complementary Metal-Oxide Semiconductor (CMOS) Direct Time Interval Measurement (DTIM) Integrated Circuit (IC) to detect the decay (fall) time of the luminescence emission when analyte-sensitive luminophores are excited with an optical pulse. The CMOS DTIM IC includes 14 × 14 phototransistor array, transimpedance amplifier, regulated gain amplifier, fall time detector, and time-to-digital convertor. We examined the DTIM system to measure the emission lifetime of oxygen-sensitive luminophores tris(4,7-diphenyl-1, 10-phenanthroline) ruthenium(II) ([Ru(dpp)(3)](2+)) encapsulated in sol-gel derived xerogel thin-films. The DTIM system fabricated using TSMC 0.35 μm process functions to detect lifetimes from 4 μs to 14.4 μs but can be tuned to detect longer lifetimes. The system provides 8-bit digital output proportional to lifetimes and consumes 4.5 mW of power with 3.3 V DC supply. The CMOS system provides a useful platform for the development of reliable, robust, and miniaturized optical chemical sensors.

  4. Time interval measurement between to emission: a systematics

    International Nuclear Information System (INIS)

    Bizard, G.; Bougault, R.; Brou, R.; Colin, J.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lopez, O.; Louvel, M.; Mahi, M.; Meslin, C.; Steckmeyer, J.C.; Tamain, B.; Wieloch, A.

    1998-01-01

    A systematic study of the evolution of intervals of fragment emission times as a function of the energy deposited in the compound system was performed. Several measurements, Ne at 60 MeV/u, Ar at 30 and 60 MeV/u and two measurements for Kr at 60 MeV/u (central and semi-peripheral collisions) are presented. In all the experiments the target was Au and the mass of the compounds system was around A = 200. The excitation energies per nucleon reached in the case of these heavy systems cover the range of 3 to 5.5 MeV/u. The method used to determine the emission time intervals is based on the correlation functions associated to the relative angle distributions. The gaps between the data and simulations allow to evaluate the emission times. A rapid decrease of these time intervals was observed when the excitation energy increased. This variation starts at 500 fm/c which corresponds to a sequential emission. This relatively long time which indicates a weak interaction between fragments, corresponds practically to the measurement threshold. The shortest intervals (about 50 fm/c) are associated to a spontaneous multifragmentation and were observed in the case of central collisions at Ar+Au and Kr+Au at 60 MeV/u. Two interpretations are possible. The multifragmentation process might be viewed as a sequential process of very short time-separation or else, one can separate two zones heaving in mind that the multifragmentation is predominant from 4,5 MeV/u excitation energy upwards. This question is still open and its study is under way at LPC. An answer could come from the study of the rupture process of an excited nucleus, notably by the determination of its life-time

  5. An Integrated Method for Interval Multi-Objective Planning of a Water Resource System in the Eastern Part of Handan

    Directory of Open Access Journals (Sweden)

    Meiqin Suo

    2017-07-01

    Full Text Available In this study, an integrated solving method is proposed for interval multi-objective planning. The proposed method is based on fuzzy linear programming and an interactive two-step method. It cannot only provide objectively optimal values for multiple objectives at the same time, but also effectively offer a globally optimal interval solution. Meanwhile, the degree of satisfaction related to different objective functions would be obtained. Then, the integrated solving method for interval multi-objective planning is applied to a case study of planning multi-water resources joint scheduling under uncertainty in the eastern part of Handan, China. The solutions obtained are useful for decision makers in easing the contradiction between supply of multi-water resources and demand from different water users. Moreover, it can provide the optimal comprehensive benefits of economy, society, and the environment.

  6. Time interval measurement between two emissions: Ar + Au

    International Nuclear Information System (INIS)

    Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Durand, D.; Genoux-Lubain, A.; Hamdani, T.; Horn, D.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Louvel, M.; Peter, J.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.

    1998-01-01

    The Ar + Au system was studied at two bombarding energies, 30 and 60 A.MeV. The comparison of the distributions of fragment emission angles in central collisions was carried out by means of a simulation allowing the emission time interval variation. It was found that this interval depends on the bombarding energy (i.e. deposed excitation energy).For 30 A.MeV this interval is 500 fm/c (0.33 · 10 -23 s), while for 60 A.MeV it is so short that the multifragmentation concept can be used

  7. Nonparametric Estimation of Interval Reliability for Discrete-Time Semi-Markov Systems

    DEFF Research Database (Denmark)

    Georgiadis, Stylianos; Limnios, Nikolaos

    2016-01-01

    In this article, we consider a repairable discrete-time semi-Markov system with finite state space. The measure of the interval reliability is given as the probability of the system being operational over a given finite-length time interval. A nonparametric estimator is proposed for the interval...

  8. Foundation for a Time Interval Access Control Model

    National Research Council Canada - National Science Library

    Afinidad, Francis B; Levin, Timothy E; Irvine, Cynthia E; Nguyen, Thuy D

    2005-01-01

    A new model for representing temporal access control policies is introduced. In this model, temporal authorizations are represented by time attributes associated with both subjects and objects, and a time interval access graph...

  9. The duration of uncertain times: audiovisual information about intervals is integrated in a statistically optimal fashion.

    Directory of Open Access Journals (Sweden)

    Jess Hartcher-O'Brien

    Full Text Available Often multisensory information is integrated in a statistically optimal fashion where each sensory source is weighted according to its precision. This integration scheme isstatistically optimal because it theoretically results in unbiased perceptual estimates with the highest precisionpossible.There is a current lack of consensus about how the nervous system processes multiple sensory cues to elapsed time.In order to shed light upon this, we adopt a computational approach to pinpoint the integration strategy underlying duration estimationof audio/visual stimuli. One of the assumptions of our computational approach is that the multisensory signals redundantly specify the same stimulus property. Our results clearly show that despite claims to the contrary, perceived duration is the result of an optimal weighting process, similar to that adopted for estimates of space. That is, participants weight the audio and visual information to arrive at the most precise, single duration estimate possible. The work also disentangles how different integration strategies - i.e. consideringthe time of onset/offset ofsignals - might alter the final estimate. As such we provide the first concrete evidence of an optimal integration strategy in human duration estimates.

  10. Interval-Valued Intuitionistic Fuzzy Multicriteria Group Decision Making Based on VIKOR and Choquet Integral

    Directory of Open Access Journals (Sweden)

    Chunqiao Tan

    2013-01-01

    Full Text Available An effective decision making approach based on VIKOR and Choquet integral is developed to solve multicriteria group decision making problem with conflicting criteria and interdependent subjective preference of decision makers in a fuzzy environment where preferences of decision makers with respect to criteria are represented by interval-valued intuitionistic fuzzy sets. First, an interval-valued intuitionistic fuzzy Choquet integral operator is given. Some of its properties are investigated in detail. The extended VIKOR decision procedure based on the proposed operator is developed for solving the multicriteria group decision making problem where the interactive criteria weight is measured by Shapley value. An illustrative example is given for demonstrating the applicability of the proposed decision procedure for solving the multi-criteria group decision making problem in interval-valued intuitionistic fuzzy environment.

  11. Inactivation of the Medial-Prefrontal Cortex Impairs Interval Timing Precision, but Not Timing Accuracy or Scalar Timing in a Peak-Interval Procedure in Rats

    Directory of Open Access Journals (Sweden)

    Catalin V. Buhusi

    2018-06-01

    Full Text Available Motor sequence learning, planning and execution of goal-directed behaviors, and decision making rely on accurate time estimation and production of durations in the seconds-to-minutes range. The pathways involved in planning and execution of goal-directed behaviors include cortico-striato-thalamo-cortical circuitry modulated by dopaminergic inputs. A critical feature of interval timing is its scalar property, by which the precision of timing is proportional to the timed duration. We examined the role of medial prefrontal cortex (mPFC in timing by evaluating the effect of its reversible inactivation on timing accuracy, timing precision and scalar timing. Rats were trained to time two durations in a peak-interval (PI procedure. Reversible mPFC inactivation using GABA agonist muscimol resulted in decreased timing precision, with no effect on timing accuracy and scalar timing. These results are partly at odds with studies suggesting that ramping prefrontal activity is crucial to timing but closely match simulations with the Striatal Beat Frequency (SBF model proposing that timing is coded by the coincidental activation of striatal neurons by cortical inputs. Computer simulations indicate that in SBF, gradual inactivation of cortical inputs results in a gradual decrease in timing precision with preservation of timing accuracy and scalar timing. Further studies are needed to differentiate between timing models based on coincidence detection and timing models based on ramping mPFC activity, and clarify whether mPFC is specifically involved in timing, or more generally involved in attention, working memory, or response selection/inhibition.

  12. A novel interval type-2 fractional order fuzzy PID controller: Design, performance evaluation, and its optimal time domain tuning.

    Science.gov (United States)

    Kumar, Anupam; Kumar, Vijay

    2017-05-01

    In this paper, a novel concept of an interval type-2 fractional order fuzzy PID (IT2FO-FPID) controller, which requires fractional order integrator and fractional order differentiator, is proposed. The incorporation of Takagi-Sugeno-Kang (TSK) type interval type-2 fuzzy logic controller (IT2FLC) with fractional controller of PID-type is investigated for time response measure due to both unit step response and unit load disturbance. The resulting IT2FO-FPID controller is examined on different delayed linear and nonlinear benchmark plants followed by robustness analysis. In order to design this controller, fractional order integrator-differentiator operators are considered as design variables including input-output scaling factors. A new hybridized algorithm named as artificial bee colony-genetic algorithm (ABC-GA) is used to optimize the parameters of the controller while minimizing weighted sum of integral of time absolute error (ITAE) and integral of square of control output (ISCO). To assess the comparative performance of the IT2FO-FPID, authors compared it against existing controllers, i.e., interval type-2 fuzzy PID (IT2-FPID), type-1 fractional order fuzzy PID (T1FO-FPID), type-1 fuzzy PID (T1-FPID), and conventional PID controllers. Furthermore, to show the effectiveness of the proposed controller, the perturbed processes along with the larger dead time are tested. Moreover, the proposed controllers are also implemented on multi input multi output (MIMO), coupled, and highly complex nonlinear two-link robot manipulator system in presence of un-modeled dynamics. Finally, the simulation results explicitly indicate that the performance of the proposed IT2FO-FPID controller is superior to its conventional counterparts in most of the cases. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  13. Perception of short time scale intervals in a hypnotic virtuoso

    NARCIS (Netherlands)

    Noreika, Valdas; Falter, Christine M.; Arstila, Valtteri; Wearden, John H.; Kallio, Sakari

    2012-01-01

    Previous studies showed that hypnotized individuals underestimate temporal intervals in the range of several seconds to tens of minutes. However, no previous work has investigated whether duration perception is equally disorderly when shorter time intervals are probed. In this study, duration

  14. Cardiac time intervals by tissue Doppler imaging M-mode echocardiography

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor

    2016-01-01

    for myocardial myocytes to achieve an LV pressure equal to that of aorta increases, resulting in a prolongation of the isovolumic contraction time (IVCT). Furthermore, the ability of myocardial myocytes to maintain the LV pressure decreases, resulting in reduction in the ejection time (ET). As LV diastolic...... of whether the LV is suffering from impaired systolic or diastolic function. A novel method of evaluating the cardiac time intervals has recently evolved. Using tissue Doppler imaging (TDI) M-mode through the mitral valve (MV) to estimate the cardiac time intervals may be an improved method reflecting global...

  15. Across-province standardization and comparative analysis of time-to-care intervals for cancer

    Directory of Open Access Journals (Sweden)

    Nugent Zoann

    2007-10-01

    Full Text Available Abstract Background A set of consistent, standardized definitions of intervals and populations on which to report across provinces is needed to inform the Provincial/Territorial Deputy Ministries of Health on progress of the Ten-Year Plan to Strengthen Health Care. The objectives of this project were to: 1 identify a set of criteria and variables needed to create comparable measures of important time-to-cancer-care intervals that could be applied across provinces and 2 use the measures to compare time-to-care across participating provinces for lung and colorectal cancer patients diagnosed in 2004. Methods A broad-based group of stakeholders from each of the three participating cancer agencies was assembled to identify criteria for time-to-care intervals to standardize, evaluate possible intervals and their corresponding start and end time points, and finalize the selection of intervals to pursue. Inclusion/exclusion criteria were identified for the patient population and the selected time points to reduce potential selection bias. The provincial 2004 colorectal and lung cancer data were used to illustrate across-province comparisons for the selected time-to-care intervals. Results Criteria identified as critical for time-to-care intervals and corresponding start and end points were: 1 relevant to patients, 2 relevant to clinical care, 3 unequivocally defined, and 4 currently captured consistently across cancer agencies. Time from diagnosis to first radiation or chemotherapy treatment and the smaller components, time from diagnosis to first consult with an oncologist and time from first consult to first radiation or chemotherapy treatment, were the only intervals that met all four criteria. Timeliness of care for the intervals evaluated was similar between the provinces for lung cancer patients but significant differences were found for colorectal cancer patients. Conclusion We identified criteria important for selecting time-to-care intervals

  16. Interval timing under a behavioral microscope: Dissociating motivational and timing processes in fixed-interval performance.

    Science.gov (United States)

    Daniels, Carter W; Sanabria, Federico

    2017-03-01

    The distribution of latencies and interresponse times (IRTs) of rats was compared between two fixed-interval (FI) schedules of food reinforcement (FI 30 s and FI 90 s), and between two levels of food deprivation. Computational modeling revealed that latencies and IRTs were well described by mixture probability distributions embodying two-state Markov chains. Analysis of these models revealed that only a subset of latencies is sensitive to the periodicity of reinforcement, and prefeeding only reduces the size of this subset. The distribution of IRTs suggests that behavior in FI schedules is organized in bouts that lengthen and ramp up in frequency with proximity to reinforcement. Prefeeding slowed down the lengthening of bouts and increased the time between bouts. When concatenated, latency and IRT models adequately reproduced sigmoidal FI response functions. These findings suggest that behavior in FI schedules fluctuates in and out of schedule control; an account of such fluctuation suggests that timing and motivation are dissociable components of FI performance. These mixture-distribution models also provide novel insights on the motivational, associative, and timing processes expressed in FI performance. These processes may be obscured, however, when performance in timing tasks is analyzed in terms of mean response rates.

  17. Optimal time interval for induction of immunologic adaptive response

    International Nuclear Information System (INIS)

    Ju Guizhi; Song Chunhua; Liu Shuzheng

    1994-01-01

    The optimal time interval between prior dose (D1) and challenge dose (D2) for the induction of immunologic adaptive response was investigated. Kunming mice were exposed to 75 mGy X-rays at a dose rate of 12.5 mGy/min. 3, 6, 12, 24 or 60 h after the prior irradiation the mice were challenged with a dose of 1.5 Gy at a dose rate of 0.33 Gy/min. 18h after D2, the mice were sacrificed for examination of immunological parameters. The results showed that with an interval of 6 h between D1 and D2, the adaptive response of the reaction of splenocytes to LPS was induced, and with an interval of 12 h the adaptive responses of spontaneous incorporation of 3 H-TdR into thymocytes and the reaction of splenocytes to Con A and LPS were induced with 75 mGy prior irradiation. The data suggested that the optimal time intervals between D1 and D2 for the induction of immunologic adaptive response were 6 h and 12 h with a D1 of 75 mGy and a D2 of 1.5 Gy. The mechanism of immunologic adaptation following low dose radiation is discussed

  18. Measurement of the ecological flow of the Acaponeta river, Nayarit, comparing different time intervals

    Directory of Open Access Journals (Sweden)

    Guadalupe de la Lanza Espino

    2012-07-01

    Full Text Available The diverse management of river water in Mexico has been unequal due to the different anthropological activities, and it is associated with inter-annual changes in the climate and runoff patterns, leading to a loss of the ecosystem integrity. However, nowadays there are different methods to assess the water volume that is necessary to conserve the environment, among which are hydrological methods, such as those applied here, that are based on information on water volumes recorded over decades, which are not always available in the country. For this reason, this study compares runoff records for different time ranges: minimum of 10 years, medium of 20 years, and more than 50 years, to quantify the environmental flow. These time intervals provided similar results, which mean that not only for the Acaponeta river, but possibly for others lotic systems as well, a 10-year interval may be used satisfactorily. In this river, the runoff water that must be kept for environmental purposes is: for 10 years 70.1%, for 20 years 78.1% and for >50 years 68.8%, with an average of 72.3% of the total water volume or of the average annual runoff.

  19. Formulation of an explicit-multiple-time-step time integration method for use in a global primitive equation grid model

    Science.gov (United States)

    Chao, W. C.

    1982-01-01

    With appropriate modifications, a recently proposed explicit-multiple-time-step scheme (EMTSS) is incorporated into the UCLA model. In this scheme, the linearized terms in the governing equations that generate the gravity waves are split into different vertical modes. Each mode is integrated with an optimal time step, and at periodic intervals these modes are recombined. The other terms are integrated with a time step dictated by the CFL condition for low-frequency waves. This large time step requires a special modification of the advective terms in the polar region to maintain stability. Test runs for 72 h show that EMTSS is a stable, efficient and accurate scheme.

  20. Detection of surface electromyography recording time interval without muscle fatigue effect for biceps brachii muscle during maximum voluntary contraction.

    Science.gov (United States)

    Soylu, Abdullah Ruhi; Arpinar-Avsar, Pinar

    2010-08-01

    The effects of fatigue on maximum voluntary contraction (MVC) parameters were examined by using force and surface electromyography (sEMG) signals of the biceps brachii muscles (BBM) of 12 subjects. The purpose of the study was to find the sEMG time interval of the MVC recordings which is not affected by the muscle fatigue. At least 10s of force and sEMG signals of BBM were recorded simultaneously during MVC. The subjects reached the maximum force level within 2s by slightly increasing the force, and then contracted the BBM maximally. The time index of each sEMG and force signal were labeled with respect to the time index of the maximum force (i.e. after the time normalization, each sEMG or force signal's 0s time index corresponds to maximum force point). Then, the first 8s of sEMG and force signals were divided into 0.5s intervals. Mean force, median frequency (MF) and integrated EMG (iEMG) values were calculated for each interval. Amplitude normalization was performed by dividing the force signals to their mean values of 0s time intervals (i.e. -0.25 to 0.25s). A similar amplitude normalization procedure was repeated for the iEMG and MF signals. Statistical analysis (Friedman test with Dunn's post hoc test) was performed on the time and amplitude normalized signals (MF, iEMG). Although the ANOVA results did not give statistically significant information about the onset of the muscle fatigue, linear regression (mean force vs. time) showed a decreasing slope (Pearson-r=0.9462, pfatigue starts after the 0s time interval as the muscles cannot attain their peak force levels. This implies that the most reliable interval for MVC calculation which is not affected by the muscle fatigue is from the onset of the EMG activity to the peak force time. Mean, SD, and range of this interval (excluding 2s gradual increase time) for 12 subjects were 2353, 1258ms and 536-4186ms, respectively. Exceeding this interval introduces estimation errors in the maximum amplitude calculations

  1. Cerebellar Roles in Self-Timing for Sub- and Supra-Second Intervals.

    Science.gov (United States)

    Ohmae, Shogo; Kunimatsu, Jun; Tanaka, Masaki

    2017-03-29

    Previous studies suggest that the cerebellum and basal ganglia are involved in sub-second and supra-second timing, respectively. To test this hypothesis at the cellular level, we examined the activity of single neurons in the cerebellar dentate nucleus in monkeys performing the oculomotor version of the self-timing task. Animals were trained to report the passage of time of 400, 600, 1200, or 2400 ms following a visual cue by making self-initiated memory-guided saccades. We found a sizeable preparatory neuronal activity before self-timed saccades across delay intervals, while the time course of activity correlated with the trial-by-trial variation of saccade latency in different ways depending on the length of the delay intervals. For the shorter delay intervals, the ramping up of neuronal firing rate started just after the visual cue and the rate of rise of neuronal activity correlated with saccade timing. In contrast, for the longest delay (2400 ms), the preparatory activity started late during the delay period, and its onset time correlated with self-timed saccade latency. Because electrical microstimulation applied to the recording sites during saccade preparation advanced self-timed but not reactive saccades, regardless of their directions, the signals in the cerebellum may have a causal role in self-timing. We suggest that the cerebellum may regulate timing in both sub-second and supra-second ranges, although its relative contribution might be greater for sub-second than for supra-second time intervals. SIGNIFICANCE STATEMENT How we decide the timing of self-initiated movement is a fundamental question. According to the prevailing hypothesis, the cerebellum plays a role in monitoring sub-second timing, whereas the basal ganglia are important for supra-second timing. To verify this, we explored neuronal signals in the monkey cerebellum while animals reported the passage of time in the range 400-2400 ms by making eye movements. Contrary to our expectations, we

  2. Optimizing some 3-stage W-methods for the time integration of PDEs

    Science.gov (United States)

    Gonzalez-Pinto, S.; Hernandez-Abreu, D.; Perez-Rodriguez, S.

    2017-07-01

    The optimization of some W-methods for the time integration of time-dependent PDEs in several spatial variables is considered. In [2, Theorem 1] several three-parametric families of three-stage W-methods for the integration of IVPs in ODEs were studied. Besides, the optimization of several specific methods for PDEs when the Approximate Matrix Factorization Splitting (AMF) is used to define the approximate Jacobian matrix (W ≈ fy(yn)) was carried out. Also, some convergence and stability properties were presented [2]. The derived methods were optimized on the base that the underlying explicit Runge-Kutta method is the one having the largest Monotonicity interval among the thee-stage order three Runge-Kutta methods [1]. Here, we propose an optimization of the methods by imposing some additional order condition [7] to keep order three for parabolic PDE problems [6] but at the price of reducing substantially the length of the nonlinear Monotonicity interval of the underlying explicit Runge-Kutta method.

  3. Entrained rhythmic activities of neuronal ensembles as perceptual memory of time interval.

    Science.gov (United States)

    Sumbre, Germán; Muto, Akira; Baier, Herwig; Poo, Mu-ming

    2008-11-06

    The ability to process temporal information is fundamental to sensory perception, cognitive processing and motor behaviour of all living organisms, from amoebae to humans. Neural circuit mechanisms based on neuronal and synaptic properties have been shown to process temporal information over the range of tens of microseconds to hundreds of milliseconds. How neural circuits process temporal information in the range of seconds to minutes is much less understood. Studies of working memory in monkeys and rats have shown that neurons in the prefrontal cortex, the parietal cortex and the thalamus exhibit ramping activities that linearly correlate with the lapse of time until the end of a specific time interval of several seconds that the animal is trained to memorize. Many organisms can also memorize the time interval of rhythmic sensory stimuli in the timescale of seconds and can coordinate motor behaviour accordingly, for example, by keeping the rhythm after exposure to the beat of music. Here we report a form of rhythmic activity among specific neuronal ensembles in the zebrafish optic tectum, which retains the memory of the time interval (in the order of seconds) of repetitive sensory stimuli for a duration of up to approximately 20 s. After repetitive visual conditioning stimulation (CS) of zebrafish larvae, we observed rhythmic post-CS activities among specific tectal neuronal ensembles, with a regular interval that closely matched the CS. Visuomotor behaviour of the zebrafish larvae also showed regular post-CS repetitions at the entrained time interval that correlated with rhythmic neuronal ensemble activities in the tectum. Thus, rhythmic activities among specific neuronal ensembles may act as an adjustable 'metronome' for time intervals in the order of seconds, and serve as a mechanism for the short-term perceptual memory of rhythmic sensory experience.

  4. Long Pulse Integrator of Variable Integral Time Constant

    International Nuclear Information System (INIS)

    Wang Yong; Ji Zhenshan; Du Xiaoying; Wu Yichun; Li Shi; Luo Jiarong

    2010-01-01

    A kind of new long pulse integrator was designed based on the method of variable integral time constant and deducting integral drift by drift slope. The integral time constant can be changed by choosing different integral resistors, in order to improve the signal-to-noise ratio, and avoid output saturation; the slope of integral drift of a certain period of time can be calculated by digital signal processing, which can be used to deduct the drift of original integral signal in real time to reduce the integral drift. The tests show that this kind of long pulse integrator is good at reducing integral drift, which also can eliminate the effects of changing integral time constant. According to experiments, the integral time constant can be changed by remote control and manual adjustment of integral drift is avoided, which can improve the experiment efficiency greatly and can be used for electromagnetic measurement in Tokamak experiment. (authors)

  5. Optimal unit sizing for small-scale integrated energy systems using multi-objective interval optimization and evidential reasoning approach

    International Nuclear Information System (INIS)

    Wei, F.; Wu, Q.H.; Jing, Z.X.; Chen, J.J.; Zhou, X.X.

    2016-01-01

    This paper proposes a comprehensive framework including a multi-objective interval optimization model and evidential reasoning (ER) approach to solve the unit sizing problem of small-scale integrated energy systems, with uncertain wind and solar energies integrated. In the multi-objective interval optimization model, interval variables are introduced to tackle the uncertainties of the optimization problem. Aiming at simultaneously considering the cost and risk of a business investment, the average and deviation of life cycle cost (LCC) of the integrated energy system are formulated. In order to solve the problem, a novel multi-objective optimization algorithm, MGSOACC (multi-objective group search optimizer with adaptive covariance matrix and chaotic search), is developed, employing adaptive covariance matrix to make the search strategy adaptive and applying chaotic search to maintain the diversity of group. Furthermore, ER approach is applied to deal with multiple interests of an investor at the business decision making stage and to determine the final unit sizing solution from the Pareto-optimal solutions. This paper reports on the simulation results obtained using a small-scale direct district heating system (DH) and a small-scale district heating and cooling system (DHC) optimized by the proposed framework. The results demonstrate the superiority of the multi-objective interval optimization model and ER approach in tackling the unit sizing problem of integrated energy systems considering the integration of uncertian wind and solar energies. - Highlights: • Cost and risk of investment in small-scale integrated energy systems are considered. • A multi-objective interval optimization model is presented. • A novel multi-objective optimization algorithm (MGSOACC) is proposed. • The evidential reasoning (ER) approach is used to obtain the final optimal solution. • The MGSOACC and ER can tackle the unit sizing problem efficiently.

  6. Working time intervals and total work time on nursing positions in Poland

    Directory of Open Access Journals (Sweden)

    Danuta Kunecka

    2015-06-01

    Full Text Available Background: For the last few years a topic of overwork on nursing posts has given rise to strong discussions. The author has set herself a goal of answering the question if it is a result of real overwork of this particular profession or rather commonly assumed frustration of this professional group. The aim of this paper is to conduct the analysis of working time on chosen nursing positions in relation to measures of time being used as intervals in the course of conducting standard professional activities during one working day. Material and Methods: Research material consisted of documentation of work time on chosen nursing workplaces, compiled between 2007–2012 within the framework of a nursing course at the Pomeranian Medical University in Szczecin. As a method of measurement a photograph of a working day has been used. Measurements were performed in institutions located in 6 voivodeships in Poland. Results: Results suggest that only 6.5% of total of surveyed representatives of nurse profession spends proper amount of time (meaning: a time set by the applicable standards on work intervals during a working day. Conclusions: The scale of the phenomenon indicates excessive workload for nursing positions, which along with a longer period of time, longer working hours may cause decrease in efficiency of work and cause a drop in quality of provided services. Med Pr 2015;66,(2:165–172

  7. Time-variant random interval natural frequency analysis of structures

    Science.gov (United States)

    Wu, Binhua; Wu, Di; Gao, Wei; Song, Chongmin

    2018-02-01

    This paper presents a new robust method namely, unified interval Chebyshev-based random perturbation method, to tackle hybrid random interval structural natural frequency problem. In the proposed approach, random perturbation method is implemented to furnish the statistical features (i.e., mean and standard deviation) and Chebyshev surrogate model strategy is incorporated to formulate the statistical information of natural frequency with regards to the interval inputs. The comprehensive analysis framework combines the superiority of both methods in a way that computational cost is dramatically reduced. This presented method is thus capable of investigating the day-to-day based time-variant natural frequency of structures accurately and efficiently under concrete intrinsic creep effect with probabilistic and interval uncertain variables. The extreme bounds of the mean and standard deviation of natural frequency are captured through the embedded optimization strategy within the analysis procedure. Three particularly motivated numerical examples with progressive relationship in perspective of both structure type and uncertainty variables are demonstrated to justify the computational applicability, accuracy and efficiency of the proposed method.

  8. Precision Interval Estimation of the Response Surface by Means of an Integrated Algorithm of Neural Network and Linear Regression

    Science.gov (United States)

    Lo, Ching F.

    1999-01-01

    The integration of Radial Basis Function Networks and Back Propagation Neural Networks with the Multiple Linear Regression has been accomplished to map nonlinear response surfaces over a wide range of independent variables in the process of the Modem Design of Experiments. The integrated method is capable to estimate the precision intervals including confidence and predicted intervals. The power of the innovative method has been demonstrated by applying to a set of wind tunnel test data in construction of response surface and estimation of precision interval.

  9. Brain response during the M170 time interval is sensitive to socially relevant information.

    Science.gov (United States)

    Arviv, Oshrit; Goldstein, Abraham; Weeting, Janine C; Becker, Eni S; Lange, Wolf-Gero; Gilboa-Schechtman, Eva

    2015-11-01

    Deciphering the social meaning of facial displays is a highly complex neurological process. The M170, an event related field component of MEG recording, like its EEG counterpart N170, was repeatedly shown to be associated with structural encoding of faces. However, the scope of information encoded during the M170 time window is still being debated. We investigated the neuronal origin of facial processing of integrated social rank cues (SRCs) and emotional facial expressions (EFEs) during the M170 time interval. Participants viewed integrated facial displays of emotion (happy, angry, neutral) and SRCs (indicated by upward, downward, or straight head tilts). We found that the activity during the M170 time window is sensitive to both EFEs and SRCs. Specifically, highly prominent activation was observed in response to SRC connoting dominance as compared to submissive or egalitarian head cues. Interestingly, the processing of EFEs and SRCs appeared to rely on different circuitry. Our findings suggest that vertical head tilts are processed not only for their sheer structural variance, but as social information. Exploring the temporal unfolding and brain localization of non-verbal cues processing may assist in understanding the functioning of the social rank biobehavioral system. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Interval Timing Deficits Assessed by Time Reproduction Dual Tasks as Cognitive Endophenotypes for Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Hwang-Gu, Shoou-Lian; Gau, Susan Shur-Fen

    2015-01-01

    The literature has suggested timing processing as a potential endophenotype for attention deficit/hyperactivity disorder (ADHD); however, whether the subjective internal clock speed presented by verbal estimation and limited attention capacity presented by time reproduction could be endophenotypes for ADHD is still unknown. We assessed 223 youths with DSM-IV ADHD (age range: 10-17 years), 105 unaffected siblings, and 84 typically developing (TD) youths using psychiatric interviews, intelligence tests, verbal estimation and time reproduction tasks (single task and simple and difficult dual tasks) at 5-second, 12-second, and 17-second intervals. We found that youths with ADHD tended to overestimate time in verbal estimation more than their unaffected siblings and TD youths, implying that fast subjective internal clock speed might be a characteristic of ADHD, rather than an endophenotype for ADHD. Youths with ADHD and their unaffected siblings were less precise in time reproduction dual tasks than TD youths. The magnitude of estimated errors in time reproduction was greater in youths with ADHD and their unaffected siblings than in TD youths, with an increased time interval at the 17-second interval and with increased task demands on both simple and difficult dual tasks versus the single task. Increased impaired time reproduction in dual tasks with increased intervals and task demands were shown in youths with ADHD and their unaffected siblings, suggesting that time reproduction deficits explained by limited attention capacity might be a useful endophenotype of ADHD. PMID:25992899

  11. Investigations of timing during the schedule and reinforcement intervals with wheel-running reinforcement.

    Science.gov (United States)

    Belke, Terry W; Christie-Fougere, Melissa M

    2006-11-01

    Across two experiments, a peak procedure was used to assess the timing of the onset and offset of an opportunity to run as a reinforcer. The first experiment investigated the effect of reinforcer duration on temporal discrimination of the onset of the reinforcement interval. Three male Wistar rats were exposed to fixed-interval (FI) 30-s schedules of wheel-running reinforcement and the duration of the opportunity to run was varied across values of 15, 30, and 60s. Each session consisted of 50 reinforcers and 10 probe trials. Results showed that as reinforcer duration increased, the percentage of postreinforcement pauses longer than the 30-s schedule interval increased. On probe trials, peak response rates occurred near the time of reinforcer delivery and peak times varied with reinforcer duration. In a second experiment, seven female Long-Evans rats were exposed to FI 30-s schedules leading to 30-s opportunities to run. Timing of the onset and offset of the reinforcement period was assessed by probe trials during the schedule interval and during the reinforcement interval in separate conditions. The results provided evidence of timing of the onset, but not the offset of the wheel-running reinforcement period. Further research is required to assess if timing occurs during a wheel-running reinforcement period.

  12. Infinite time interval backward stochastic differential equations with continuous coefficients.

    Science.gov (United States)

    Zong, Zhaojun; Hu, Feng

    2016-01-01

    In this paper, we study the existence theorem for [Formula: see text] [Formula: see text] solutions to a class of 1-dimensional infinite time interval backward stochastic differential equations (BSDEs) under the conditions that the coefficients are continuous and have linear growths. We also obtain the existence of a minimal solution. Furthermore, we study the existence and uniqueness theorem for [Formula: see text] [Formula: see text] solutions of infinite time interval BSDEs with non-uniformly Lipschitz coefficients. It should be pointed out that the assumptions of this result is weaker than that of Theorem 3.1 in Zong (Turkish J Math 37:704-718, 2013).

  13. Evaluating Protocol Lifecycle Time Intervals in HIV/AIDS Clinical Trials

    Science.gov (United States)

    Schouten, Jeffrey T.; Dixon, Dennis; Varghese, Suresh; Cope, Marie T.; Marci, Joe; Kagan, Jonathan M.

    2014-01-01

    Background Identifying efficacious interventions for the prevention and treatment of human diseases depends on the efficient development and implementation of controlled clinical trials. Essential to reducing the time and burden of completing the clinical trial lifecycle is determining which aspects take the longest, delay other stages, and may lead to better resource utilization without diminishing scientific quality, safety, or the protection of human subjects. Purpose In this study we modeled time-to-event data to explore relationships between clinical trial protocol development and implementation times, as well as identify potential correlates of prolonged development and implementation. Methods We obtained time interval and participant accrual data from 111 interventional clinical trials initiated between 2006 and 2011 by NIH’s HIV/AIDS Clinical Trials Networks. We determined the time (in days) required to complete defined phases of clinical trial protocol development and implementation. Kaplan-Meier estimates were used to assess the rates at which protocols reached specified terminal events, stratified by study purpose (therapeutic, prevention) and phase group (pilot/phase I, phase II, and phase III/ IV). We also examined several potential correlates to prolonged development and implementation intervals. Results Even though phase grouping did not determine development or implementation times of either therapeutic or prevention studies, overall we observed wide variation in protocol development times. Moreover, we detected a trend toward phase III/IV therapeutic protocols exhibiting longer developmental (median 2 ½ years) and implementation times (>3years). We also found that protocols exceeding the median number of days for completing the development interval had significantly longer implementation. Limitations The use of a relatively small set of protocols may have limited our ability to detect differences across phase groupings. Some timing effects

  14. A Comparative Risk Assessment of Extended Integrated Leak Rate Testing Intervals

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Ji Yong; Hwang, Seok Won; Lee, Byung Sik [Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2009-10-15

    This paper presents the risk impacts of extending the Integrated Leak Rate Testing (ILRT) intervals (from five years to ten years) of Yonggwang (YGN) Unit 1 and 2. These risk impacts depended on the annual variances of meteorological data and resident population. Main comparisons were performed between the initial risk assessment (2005) for the purpose of extending ILRT interval and risk reassessment (2009) where the changed plant internal configurations (core inventory and radioisotope release fraction) and plant external alterations (wind directions, rainfall and population distributions) were monitored. The reassessment showed that there was imperceptible risk increase when the ILRT interval was extended compared to the initial risk assessment. In addition, the increased value of the Large Early Release Frequency (LERF) also satisfied the acceptance guideline proposed on Reg. Guide 1.174. The MACCS II code was used for evaluating the offsite consequence analysis. The primary risk index were used as the Probabilistic Population Dose (PPD) by considering the early effects within 80 km. The Probabilistic Safety Assessment (PSA) of YGN 1 and 2 was applied to evaluate the accident frequency of each source term category and the used PSA scope was limited to internal event.

  15. Reconstruction of dynamical systems from interspike intervals

    International Nuclear Information System (INIS)

    Sauer, T.

    1994-01-01

    Attractor reconstruction from interspike interval (ISI) data is described, in rough analogy with Taken's theorem for attractor reconstruction from time series. Assuming a generic integrate-and-fire model coupling the dynamical system to the spike train, there is a one-to-one correspondence between the system states and interspike interval vectors of sufficiently large dimension. The correspondence has an important implication: interspike intervals can be forecast from past history. We show that deterministically driven ISI series can be distinguished from stochastically driven ISI series on the basis of prediction error

  16. [Estimation of the atrioventricular time interval by pulse Doppler in the normal fetal heart].

    Science.gov (United States)

    Hamela-Olkowska, Anita; Dangel, Joanna

    2009-08-01

    To assess normative values of the fetal atrioventricular (AV) time interval by pulse-wave Doppler methods on 5-chamber view. Fetal echocardiography exams were performed using Acuson Sequoia 512 in 140 singleton fetuses at 18 to 40 weeks of gestation with sinus rhythm and normal cardiac and extracardiac anatomy. Pulsed Doppler derived AV intervals were measured from left ventricular inflow/outflow view using transabdominal convex 3.5-6 MHz probe. The values of AV time interval ranged from 100 to 150 ms (mean 123 +/- 11.2). The AV interval was negatively correlated with the heart rhythm (page of gestation (p=0.007). However, in the same subgroup of the fetal heart rate there was no relation between AV intervals and gestational age. Therefore, the AV intervals showed only the heart rate dependence. The 95th percentiles of AV intervals according to FHR ranged from 135 to 148 ms. 1. The AV interval duration was negatively correlated with the heart rhythm. 2. Measurement of AV time interval is easy to perform and has a good reproducibility. It may be used for the fetal heart block screening in anti-Ro and anti-La positive pregnancies. 3. Normative values established in the study may help obstetricians in assessing fetal abnormalities of the AV conduction.

  17. Optimizing Time Intervals of Meteorological Data Used with Atmospheric Dose Modeling at SRS

    International Nuclear Information System (INIS)

    Simpkins, A.A.

    1999-01-01

    Measured tritium oxide concentrations in air have been compared with calculated values using routine release Gaussian plume models for different time intervals of meteorological data. These comparisons determined an optimum time interval of meteorological data used with atmospheric dose models at the Savannah River Site (SRS). Meteorological data of varying time intervals (1-yr to 10-yr) were used for the comparison. Insignificant differences are seen in using a one-year database as opposed to a five-year database. Use of a ten-year database results in slightly more conservative results. For meteorological databases of length one to five years the mean ratio of predicted to measured tritium oxide concentrations is approximately 1.25 whereas for the ten-year meteorological database the ration is closer to 1.35. Currently at the Savannah River Site a meteorological database of five years duration is used for all dose models. This study suggests no substantially improved accuracy using meteorological files of shorter or longer time intervals

  18. Cardiac Time Intervals Measured by Tissue Doppler Imaging M-mode

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Møgelvang, Rasmus; Schnohr, Peter

    2016-01-01

    function was evaluated in 1915 participants by using both conventional echocardiography and tissue Doppler imaging (TDI). The cardiac time intervals, including the isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), and ejection time (ET), were obtained by TDI M-mode through the mitral......). Additionally, they displayed a significant dose-response relationship, between increasing severity of elevated blood pressure and increasing left ventricular mass index (P

  19. The synaptic properties of cells define the hallmarks of interval timing in a recurrent neural network.

    Science.gov (United States)

    Pérez, Oswaldo; Merchant, Hugo

    2018-04-03

    Extensive research has described two key features of interval timing. The bias property is associated with accuracy and implies that time is overestimated for short intervals and underestimated for long intervals. The scalar property is linked to precision and states that the variability of interval estimates increases as a function of interval duration. The neural mechanisms behind these properties are not well understood. Here we implemented a recurrent neural network that mimics a cortical ensemble and includes cells that show paired-pulse facilitation and slow inhibitory synaptic currents. The network produces interval selective responses and reproduces both bias and scalar properties when a Bayesian decoder reads its activity. Notably, the interval-selectivity, timing accuracy, and precision of the network showed complex changes as a function of the decay time constants of the modeled synaptic properties and the level of background activity of the cells. These findings suggest that physiological values of the time constants for paired-pulse facilitation and GABAb, as well as the internal state of the network, determine the bias and scalar properties of interval timing. Significant Statement Timing is a fundamental element of complex behavior, including music and language. Temporal processing in a wide variety of contexts shows two primary features: time estimates exhibit a shift towards the mean (the bias property) and are more variable for longer intervals (the scalar property). We implemented a recurrent neural network that includes long-lasting synaptic currents, which can not only produce interval selective responses but also follow the bias and scalar properties. Interestingly, only physiological values of the time constants for paired-pulse facilitation and GABAb, as well as intermediate background activity within the network can reproduce the two key features of interval timing. Copyright © 2018 the authors.

  20. Mean Square Exponential Stability of Stochastic Switched System with Interval Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    Manlika Rajchakit

    2012-01-01

    Full Text Available This paper is concerned with mean square exponential stability of switched stochastic system with interval time-varying delays. The time delay is any continuous function belonging to a given interval, but not necessary to be differentiable. By constructing a suitable augmented Lyapunov-Krasovskii functional combined with Leibniz-Newton’s formula, a switching rule for the mean square exponential stability of switched stochastic system with interval time-varying delays and new delay-dependent sufficient conditions for the mean square exponential stability of the switched stochastic system are first established in terms of LMIs. Numerical example is given to show the effectiveness of the obtained result.

  1. Fault detection for discrete-time LPV systems using interval observers

    Science.gov (United States)

    Zhang, Zhi-Hui; Yang, Guang-Hong

    2017-10-01

    This paper is concerned with the fault detection (FD) problem for discrete-time linear parameter-varying systems subject to bounded disturbances. A parameter-dependent FD interval observer is designed based on parameter-dependent Lyapunov and slack matrices. The design method is presented by translating the parameter-dependent linear matrix inequalities (LMIs) into finite ones. In contrast to the existing results based on parameter-independent and diagonal Lyapunov matrices, the derived disturbance attenuation, fault sensitivity and nonnegative conditions lead to less conservative LMI characterisations. Furthermore, without the need to design the residual evaluation functions and thresholds, the residual intervals generated by the interval observers are used directly for FD decision. Finally, simulation results are presented for showing the effectiveness and superiority of the proposed method.

  2. Parameters affecting temporal resolution of Time Resolved Integrative Optical Neutron Detector (TRION)

    International Nuclear Information System (INIS)

    Mor, I; Vartsky, D; Bar, D; Feldman, G; Goldberg, M B; Brandis, M; Dangendorf, V; Tittelmeier, K; Bromberger, B; Weierganz, M

    2013-01-01

    The Time-Resolved Integrative Optical Neutron (TRION) detector was developed for Fast Neutron Resonance Radiography (FNRR), a fast-neutron transmission imaging method that exploits characteristic energy-variations of the total scattering cross-section in the E n = 1–10 MeV range to detect specific elements within a radiographed object. As opposed to classical event-counting time of flight (ECTOF), it integrates the detector signal during a well-defined neutron Time of Flight window corresponding to a pre-selected energy bin, e.g., the energy-interval spanning a cross-section resonance of an element such as C, O and N. The integrative characteristic of the detector permits loss-free operation at very intense, pulsed neutron fluxes, at a cost however, of recorded temporal resolution degradation This work presents a theoretical and experimental evaluation of detector related parameters which affect temporal resolution of the TRION system

  3. Cardiac Time Intervals by Tissue Doppler Imaging M-Mode

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Mogelvang, Rasmus; de Knegt, Martina Chantal

    2016-01-01

    PURPOSE: To define normal values of the cardiac time intervals obtained by tissue Doppler imaging (TDI) M-mode through the mitral valve (MV). Furthermore, to evaluate the association of the myocardial performance index (MPI) obtained by TDI M-mode (MPITDI) and the conventional method of obtaining...

  4. Discriminator/time interval meter system evaluation report

    Energy Technology Data Exchange (ETDEWEB)

    Condreva, K. J.

    1976-04-12

    The purpose of this report is to discuss the evaluation of a modular prototype Discriminator/Time Interval Meter data acquisition unit as a useful tool in a digital diagnostics system. The characteristics, operation and calibration of each of the hardware components are discussed in some detail. A discussion of the system calibration, operation, and data ingestion and reduction is also given. System test results to date are given and discussed. Finally, recommendations and conclusions concerning the capabilities of the Discriminator/T.I.M. system based on test and calibration results to date are given.

  5. Discriminator/time interval meter system evaluation report

    International Nuclear Information System (INIS)

    Condreva, K.J.

    1976-01-01

    The purpose of this report is to discuss the evaluation of a modular prototype Discriminator/Time Interval Meter data acquisition unit as a useful tool in a digital diagnostics system. The characteristics, operation and calibration of each of the hardware components are discussed in some detail. A discussion of the system calibration, operation, and data ingestion and reduction is also given. System test results to date are given and discussed. Finally, recommendations and conclusions concerning the capabilities of the Discriminator/T.I.M. system based on test and calibration results to date are given

  6. The 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting

    International Nuclear Information System (INIS)

    Sydnor, R.L.

    1990-05-01

    Papers presented at the 22nd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting are compiled. The following subject areas are covered: Rb, Cs, and H-based frequency standards and cryogenic and trapped-ion technology; satellite laser tracking networks, GLONASS timing, intercomparison of national time scales and international telecommunications; telecommunications, power distribution, platform positioning, and geophysical survey industries; military communications and navigation systems; and dissemination of precise time and frequency by means of GPS, GLONASS, MIL STAR, LORAN, and synchronous communication satellites

  7. Probing interval timing with scalp-recorded electroencephalography (EEG).

    Science.gov (United States)

    Ng, Kwun Kei; Penney, Trevor B

    2014-01-01

    Humans, and other animals, are able to easily learn the durations of events and the temporal relationships among them in spite of the absence of a dedicated sensory organ for time. This chapter summarizes the investigation of timing and time perception using scalp-recorded electroencephalography (EEG), a non-invasive technique that measures brain electrical potentials on a millisecond time scale. Over the past several decades, much has been learned about interval timing through the examination of the characteristic features of averaged EEG signals (i.e., event-related potentials, ERPs) elicited in timing paradigms. For example, the mismatch negativity (MMN) and omission potential (OP) have been used to study implicit and explicit timing, respectively, the P300 has been used to investigate temporal memory updating, and the contingent negative variation (CNV) has been used as an index of temporal decision making. In sum, EEG measures provide biomarkers of temporal processing that allow researchers to probe the cognitive and neural substrates underlying time perception.

  8. Frequency interval balanced truncation of discrete-time bilinear systems

    DEFF Research Database (Denmark)

    Jazlan, Ahmad; Sreeram, Victor; Shaker, Hamid Reza

    2016-01-01

    This paper presents the development of a new model reduction method for discrete-time bilinear systems based on the balanced truncation framework. In many model reduction applications, it is advantageous to analyze the characteristics of the system with emphasis on particular frequency intervals...... are the solution to a pair of new generalized Lyapunov equations. The conditions for solvability of these new generalized Lyapunov equations are derived and a numerical solution method for solving these generalized Lyapunov equations is presented. Numerical examples which illustrate the usage of the new...... generalized frequency interval controllability and observability gramians as part of the balanced truncation framework are provided to demonstrate the performance of the proposed method....

  9. Count-to-count time interval distribution analysis in a fast reactor

    International Nuclear Information System (INIS)

    Perez-Navarro Gomez, A.

    1973-01-01

    The most important kinetic parameters have been measured at the zero power fast reactor CORAL-I by means of the reactor noise analysis in the time domain, using measurements of the count-to-count time intervals. (Author) 69 refs

  10. More consistent, yet less sensitive : Interval timing in autism spectrum disorders

    NARCIS (Netherlands)

    Falter, Christine M.; Noreika, Valdas; Wearden, John H.; Bailey, Anthony J.

    2012-01-01

    Even though phenomenological observations and anecdotal reports suggest atypical time processing in individuals with an autism spectrum disorder (ASD), very few psychophysical studies have investigated interval timing, and the obtained results are contradictory. The present study aimed to clarify

  11. Semiparametric regression analysis of failure time data with dependent interval censoring.

    Science.gov (United States)

    Chen, Chyong-Mei; Shen, Pao-Sheng

    2017-09-20

    Interval-censored failure-time data arise when subjects are examined or observed periodically such that the failure time of interest is not examined exactly but only known to be bracketed between two adjacent observation times. The commonly used approaches assume that the examination times and the failure time are independent or conditionally independent given covariates. In many practical applications, patients who are already in poor health or have a weak immune system before treatment usually tend to visit physicians more often after treatment than those with better health or immune system. In this situation, the visiting rate is positively correlated with the risk of failure due to the health status, which results in dependent interval-censored data. While some measurable factors affecting health status such as age, gender, and physical symptom can be included in the covariates, some health-related latent variables cannot be observed or measured. To deal with dependent interval censoring involving unobserved latent variable, we characterize the visiting/examination process as recurrent event process and propose a joint frailty model to account for the association of the failure time and visiting process. A shared gamma frailty is incorporated into the Cox model and proportional intensity model for the failure time and visiting process, respectively, in a multiplicative way. We propose a semiparametric maximum likelihood approach for estimating model parameters and show the asymptotic properties, including consistency and weak convergence. Extensive simulation studies are conducted and a data set of bladder cancer is analyzed for illustrative purposes. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  12. Robust stability analysis of uncertain stochastic neural networks with interval time-varying delay

    International Nuclear Information System (INIS)

    Feng Wei; Yang, Simon X.; Fu Wei; Wu Haixia

    2009-01-01

    This paper addresses the stability analysis problem for uncertain stochastic neural networks with interval time-varying delays. The parameter uncertainties are assumed to be norm bounded, and the delay factor is assumed to be time-varying and belong to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. A sufficient condition is derived such that for all admissible uncertainties, the considered neural network is robustly, globally, asymptotically stable in the mean square. Some stability criteria are formulated by means of the feasibility of a linear matrix inequality (LMI), which can be effectively solved by some standard numerical packages. Finally, numerical examples are provided to demonstrate the usefulness of the proposed criteria.

  13. Study on risk insight for additional ILRT interval extension

    International Nuclear Information System (INIS)

    Seo, M. R.; Hong, S. Y.; Kim, M. K.; Chung, B. S.; Oh, H. C.

    2005-01-01

    In U.S., the containment Integrated Leakage Rate Test (ILRT) interval was extended from 3 times per 10 years to once per 10 years based on NUREG-1493 'Performance-Based Containment Leak-Test Program' in 1995. In September, 2001, ILRT interval was extended up to once per 15 years based on Nuclear Energy Industry (NEI) provisional guidance 'Interim Guidance for Performing Risk Impact Assessments In Support of One-Time Extensions for Containment Integrated Leakage Rate Test Surveillance Intervals'. In Korea, the containment ILRT was performed with 5 year interval. But, in MOST(Ministry of Science and Technology) Notice 2004-15 'Standard for the Leak- Rate Test of the Nuclear Reactor Containment', the extension of the ILRT interval to once per 10 year can be allowed if some conditions are met. So, the safety analysis for the extension of Yonggwang Nuclear (YGN) Unit 1 and 2 ILRT interval extension to once per 10 years was completed based on the methodology in NUREG-1493. But, during review process by regulatory body, KINS, it was required that some various risk insight or index for risk analysis should be developed. So, we began to study NEI interim report for 15 year ILRT interval extension. As previous analysis based on NUREG-1493, MACCS II (MELCOR Accident Consequence Code System) computer code was used for the risk analysis of the population, and the population dose was selected as a reference index for the risk evaluation

  14. The importance of time interval to development of second tumor in metachronous bilateral wilms' tumor

    International Nuclear Information System (INIS)

    Paulino, Arnold C.; Thakkar, Bharat; Henderson, William G.

    1997-01-01

    Purpose: To determine whether the time interval to development of second tumor is a prognostic factor for overall survival in children with metachronous bilateral Wilms' tumor and to give a recommendation regarding screening of the contralateral kidney in patients with Wilms' tumor. Materials and Management: A literature search using MEDLINE was performed of manuscripts in the English language from 1950-1996 and identified 108 children with metachronous bilateral Wilms' tumor. Children were classified according to time interval to development of a contralateral Wilms' tumor ( 78 mos (2), 78 - < 84 mos (1), 84 - < 90 mos (0), 90 - < 96 mos (1), ≥ 96 mos (0). Analysis of overall survival in patients with a time interval of < 18 months and ≥ 18 months showed a 10 year survival of 39.6% and 55.2%, respectively (p = 0.024, log-rank test). Conclusions: Children with metachronous bilateral Wilms' tumor who develop a contralateral tumor at a time interval of ≥ 18 months from the initial Wilms' tumor had a better overall survival than children with a time interval of < 18 months. Screening by abdominal ultrasound of the contralateral kidney for more than 5 years after initial diagnosis of Wilms' tumor may not be necessary since 102/106 (96.2%) of children had a time interval to second tumor of < 60 months

  15. Procedure prediction from symbolic Electronic Health Records via time intervals analytics.

    Science.gov (United States)

    Moskovitch, Robert; Polubriaginof, Fernanda; Weiss, Aviram; Ryan, Patrick; Tatonetti, Nicholas

    2017-11-01

    Prediction of medical events, such as clinical procedures, is essential for preventing disease, understanding disease mechanism, and increasing patient quality of care. Although longitudinal clinical data from Electronic Health Records provides opportunities to develop predictive models, the use of these data faces significant challenges. Primarily, while the data are longitudinal and represent thousands of conceptual events having duration, they are also sparse, complicating the application of traditional analysis approaches. Furthermore, the framework presented here takes advantage of the events duration and gaps. International standards for electronic healthcare data represent data elements, such as procedures, conditions, and drug exposures, using eras, or time intervals. Such eras contain both an event and a duration and enable the application of time intervals mining - a relatively new subfield of data mining. In this study, we present Maitreya, a framework for time intervals analytics in longitudinal clinical data. Maitreya discovers frequent time intervals related patterns (TIRPs), which we use as prognostic markers for modelling clinical events. We introduce three novel TIRP metrics that are normalized versions of the horizontal-support, that represents the number of TIRP instances per patient. We evaluate Maitreya on 28 frequent and clinically important procedures, using the three novel TIRP representation metrics in comparison to no temporal representation and previous TIRPs metrics. We also evaluate the epsilon value that makes Allen's relations more flexible with several settings of 30, 60, 90 and 180days in comparison to the default zero. For twenty-two of these procedures, the use of temporal patterns as predictors was superior to non-temporal features, and the use of the vertically normalized horizontal support metric to represent TIRPs as features was most effective. The use of the epsilon value with thirty days was slightly better than the zero

  16. Opposite Distortions in Interval Timing Perception for Visual and Auditory Stimuli with Temporal Modulations.

    Science.gov (United States)

    Yuasa, Kenichi; Yotsumoto, Yuko

    2015-01-01

    When an object is presented visually and moves or flickers, the perception of its duration tends to be overestimated. Such an overestimation is called time dilation. Perceived time can also be distorted when a stimulus is presented aurally as an auditory flutter, but the mechanisms and their relationship to visual processing remains unclear. In the present study, we measured interval timing perception while modulating the temporal characteristics of visual and auditory stimuli, and investigated whether the interval times of visually and aurally presented objects shared a common mechanism. In these experiments, participants compared the durations of flickering or fluttering stimuli to standard stimuli, which were presented continuously. Perceived durations for auditory flutters were underestimated, while perceived durations of visual flickers were overestimated. When auditory flutters and visual flickers were presented simultaneously, these distortion effects were cancelled out. When auditory flutters were presented with a constantly presented visual stimulus, the interval timing perception of the visual stimulus was affected by the auditory flutters. These results indicate that interval timing perception is governed by independent mechanisms for visual and auditory processing, and that there are some interactions between the two processing systems.

  17. Changes in crash risk following re-timing of traffic signal change intervals.

    Science.gov (United States)

    Retting, Richard A; Chapline, Janella F; Williams, Allan F

    2002-03-01

    More than I million motor vehicle crashes occur annually at signalized intersections in the USA. The principal method used to prevent crashes associated with routine changes in signal indications is employment of a traffic signal change interval--a brief yellow and all-red period that follows the green indication. No universal practice exists for selecting the duration of change intervals, and little is known about the influence of the duration of the change interval on crash risk. The purpose of this study was to estimate potential crash effects of modifying the duration of traffic signal change intervals to conform with values associated with a proposed recommended practice published by the Institute of Transportation Engineers. A sample of 122 intersections was identified and randomly assigned to experimental and control groups. Of 51 eligible experimental sites, 40 (78%) needed signal timing changes. For the 3-year period following implementation of signal timing changes, there was an 8% reduction in reportable crashes at experimental sites relative to those occurring at control sites (P = 0.08). For injury crashes, a 12% reduction at experimental sites relative to those occurring at control sites was found (P = 0.03). Pedestrian and bicycle crashes at experimental sites decreased 37% (P = 0.03) relative to controls. Given these results and the relatively low cost of re-timing traffic signals, modifying the duration of traffic signal change intervals to conform with values associated with the Institute of Transportation Engineers' proposed recommended practice should be strongly considered by transportation agencies to reduce the frequency of urban motor vehicle crashes.

  18. Quantification of transuranic elements by time interval correlation spectroscopy of the detected neutrons

    Science.gov (United States)

    Baeten; Bruggeman; Paepen; Carchon

    2000-03-01

    The non-destructive quantification of transuranic elements in nuclear waste management or in safeguards verifications is commonly performed by passive neutron assay techniques. To minimise the number of unknown sample-dependent parameters, Neutron Multiplicity Counting (NMC) is applied. We developed a new NMC-technique, called Time Interval Correlation Spectroscopy (TICS), which is based on the measurement of Rossi-alpha time interval distributions. Compared to other NMC-techniques, TICS offers several advantages.

  19. Embodiment and the origin of interval timing: kinematic and electromyographic data.

    Science.gov (United States)

    Addyman, Caspar; Rocha, Sinead; Fautrelle, Lilian; French, Robert M; Thomas, Elizabeth; Mareschal, Denis

    2017-03-01

    Recent evidence suggests that interval timing (the judgment of durations lasting from approximately 500 ms. to a few minutes) is closely coupled to the action control system. We used surface electromyography (EMG) and motion capture technology to explore the emergence of this coupling in 4-, 6-, and 8-month-olds. We engaged infants in an active and socially relevant arm-raising task with seven cycles and response period. In one condition, cycles were slow (every 4 s); in another, they were fast (every 2 s). In the slow condition, we found evidence of time-locked sub-threshold EMG activity even in the absence of any observed overt motor responses at all three ages. This study shows that EMGs can be a more sensitive measure of interval timing in early development than overt behavior.

  20. Beat-to-beat systolic time-interval measurement from heart sounds and ECG

    International Nuclear Information System (INIS)

    Paiva, R P; Carvalho, P; Couceiro, R; Henriques, J; Antunes, M; Quintal, I; Muehlsteff, J

    2012-01-01

    Systolic time intervals are highly correlated to fundamental cardiac functions. Several studies have shown that these measurements have significant diagnostic and prognostic value in heart failure condition and are adequate for long-term patient follow-up and disease management. In this paper, we investigate the feasibility of using heart sound (HS) to accurately measure the opening and closing moments of the aortic heart valve. These moments are crucial to define the main systolic timings of the heart cycle, i.e. pre-ejection period (PEP) and left ventricular ejection time (LVET). We introduce an algorithm for automatic extraction of PEP and LVET using HS and electrocardiogram. PEP is estimated with a Bayesian approach using the signal's instantaneous amplitude and patient-specific time intervals between atrio-ventricular valve closure and aortic valve opening. As for LVET, since the aortic valve closure corresponds to the start of the S2 HS component, we base LVET estimation on the detection of the S2 onset. A comparative assessment of the main systolic time intervals is performed using synchronous signal acquisitions of the current gold standard in cardiac time-interval measurement, i.e. echocardiography, and HS. The algorithms were evaluated on a healthy population, as well as on a group of subjects with different cardiovascular diseases (CVD). In the healthy group, from a set of 942 heartbeats, the proposed algorithm achieved 7.66 ± 5.92 ms absolute PEP estimation error. For LVET, the absolute estimation error was 11.39 ± 8.98 ms. For the CVD population, 404 beats were used, leading to 11.86 ± 8.30 and 17.51 ± 17.21 ms absolute PEP and LVET errors, respectively. The results achieved in this study suggest that HS can be used to accurately estimate LVET and PEP. (paper)

  1. Time-symmetric integration in astrophysics

    Science.gov (United States)

    Hernandez, David M.; Bertschinger, Edmund

    2018-04-01

    Calculating the long-term solution of ordinary differential equations, such as those of the N-body problem, is central to understanding a wide range of dynamics in astrophysics, from galaxy formation to planetary chaos. Because generally no analytic solution exists to these equations, researchers rely on numerical methods that are prone to various errors. In an effort to mitigate these errors, powerful symplectic integrators have been employed. But symplectic integrators can be severely limited because they are not compatible with adaptive stepping and thus they have difficulty in accommodating changing time and length scales. A promising alternative is time-reversible integration, which can handle adaptive time-stepping, but the errors due to time-reversible integration in astrophysics are less understood. The goal of this work is to study analytically and numerically the errors caused by time-reversible integration, with and without adaptive stepping. We derive the modified differential equations of these integrators to perform the error analysis. As an example, we consider the trapezoidal rule, a reversible non-symplectic integrator, and show that it gives secular energy error increase for a pendulum problem and for a Hénon-Heiles orbit. We conclude that using reversible integration does not guarantee good energy conservation and that, when possible, use of symplectic integrators is favoured. We also show that time-symmetry and time-reversibility are properties that are distinct for an integrator.

  2. Time interval measurement between two emissions: Kr + Au

    International Nuclear Information System (INIS)

    Aboufirassi, M; Bougault, R.; Brou, R.; Colin, J.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Mahi, M.; Steckmeyer, J.C.; Tamain, B.

    1998-01-01

    To indicate the method allowing the determination of the emission intervals, the results obtained with the Kr + Au system at 43 and 60 A.MeV are presented. The experiments were performed with the NAUTILUS exclusive detectors. Central collisions were selected by means of a relative velocity criterion to reject the events containing a forward emitted fragment. For the two bombardment energies the data analysis shows that the formation of a compound of mass around A = 200. By comparing the fragment dynamical variables with simulations one can conclude about the simultaneity of the compound deexcitation processes. It was found that a 5 MeV/A is able to reproduce the characteristics of the detected fragments. Also, it was found that to reproduce the dynamical characteristics of the fragments issued from central collisions it was not necessary to superimpose a radial collective energy upon the Coulomb and thermal motion. The distribution of the relative angles between detected fragments is used here as a chronometer. For simultaneous ruptures the small relative angles are forbidden by the Coulomb repulsion, while for sequential processes this interdiction is the more lifted the longer the interval between the two emissions is. For the system discussed here the comparison between simulation and data has been carried out for the extreme cases, i.e. for a vanishing and infinite time interval between the two emissions, respectively. More sophisticated simulations to describe angular distributions between the emitted fragments were also developed

  3. Systolic time intervals vs invasive predictors of fluid responsiveness after coronary artery bypass surgery(dagger)

    NARCIS (Netherlands)

    Smorenberg, A.; Lust, E.J.; Beishuizen, A.; Meijer, J.H.; Verdaasdonk, R.M.; Groeneveld, A.B.J.

    2013-01-01

    OBJECTIVES: Haemodynamic parameters for predicting fluid responsiveness in intensive care patients are invasive, technically challenging or not universally applicable. We compared the initial systolic time interval (ISTI), a non-invasive measure of the time interval between the electrical and

  4. Characterization of Cardiac Time Intervals in Healthy Bonnet Macaques (Macaca radiata) by Using an Electronic Stethoscope

    Science.gov (United States)

    Kamran, Haroon; Salciccioli, Louis; Pushilin, Sergei; Kumar, Paraag; Carter, John; Kuo, John; Novotney, Carol; Lazar, Jason M

    2011-01-01

    Nonhuman primates are used frequently in cardiovascular research. Cardiac time intervals derived by phonocardiography have long been used to assess left ventricular function. Electronic stethoscopes are simple low-cost systems that display heart sound signals. We assessed the use of an electronic stethoscope to measure cardiac time intervals in 48 healthy bonnet macaques (age, 8 ± 5 y) based on recorded heart sounds. Technically adequate recordings were obtained from all animals and required 1.5 ± 1.3 min. The following cardiac time intervals were determined by simultaneously recording acoustic and single-lead electrocardiographic data: electromechanical activation time (QS1), electromechanical systole (QS2), the time interval between the first and second heart sounds (S1S2), and the time interval between the second and first sounds (S2S1). QS2 was correlated with heart rate, mean arterial pressure, diastolic blood pressure, and left ventricular ejection time determined by using echocardiography. S1S2 correlated with heart rate, mean arterial pressure, diastolic blood pressure, left ventricular ejection time, and age. S2S1 correlated with heart rate, mean arterial pressure, diastolic blood pressure, systolic blood pressure, and left ventricular ejection time. QS1 did not correlate with any anthropometric or echocardiographic parameter. The relation S1S2/S2S1 correlated with systolic blood pressure. On multivariate analyses, heart rate was the only independent predictor of QS2, S1S2, and S2S1. In conclusion, determination of cardiac time intervals is feasible and reproducible by using an electrical stethoscope in nonhuman primates. Heart rate is a major determinant of QS2, S1S2, and S2S1 but not QS1; regression equations for reference values for cardiac time intervals in bonnet macaques are provided. PMID:21439218

  5. Unified integration intervals for the structural characterization of oil, coal or fractions there of by 1h NMR and 13c NMR

    International Nuclear Information System (INIS)

    Avella, Eliseo; Fierro, Ricardo

    2010-01-01

    Based on an analysis of publications reported between 1972 and 2006, it became clear that there are inaccuracies in the limits of the ranges of integration that the authors assigned to signals in nuclear magnetic resonance (NMR) to the structural characterization of petroleum, coals and their derived fractions, from their hydrogen (1H NMR) and carbon (13C NMR) spectra. Consequently, consolidated limits were determined for the integration of 1H NMR spectra and 13C NMR of these samples using a statistical treatment applied to the limits of integration intervals already published. With these unified limits, correlation NMR charts were developed that are useful for the allocation of the integral at such intervals, and at smaller intervals defined in terms of the intersection between different assignments. Also raised equations needed to establish the integral attributable to specific fragments in an attempt to make a more accurate structural characterization from NMR spectra of oil, coal or fractions derived.

  6. An interval-valued 2-tuple linguistic group decision-making model based on the Choquet integral operator

    Science.gov (United States)

    Liu, Bingsheng; Fu, Meiqing; Zhang, Shuibo; Xue, Bin; Zhou, Qi; Zhang, Shiruo

    2018-01-01

    The Choquet integral (IL) operator is an effective approach for handling interdependence among decision attributes in complex decision-making problems. However, the fuzzy measures of attributes and attribute sets required by IL are difficult to achieve directly, which limits the application of IL. This paper proposes a new method for determining fuzzy measures of attributes by extending Marichal's concept of entropy for fuzzy measure. To well represent the assessment information, interval-valued 2-tuple linguistic context is utilised to represent information. Then, we propose a Choquet integral operator in an interval-valued 2-tuple linguistic environment, which can effectively handle the correlation between attributes. In addition, we apply these methods to solve multi-attribute group decision-making problems. The feasibility and validity of the proposed operator is demonstrated by comparisons with other models in illustrative example part.

  7. The time interval distribution of sand–dust storms in theory: testing with observational data for Yanchi, China

    International Nuclear Information System (INIS)

    Liu, Guoliang; Zhang, Feng; Hao, Lizhen

    2012-01-01

    We previously introduced a time record model for use in studying the duration of sand–dust storms. In the model, X is the normalized wind speed and Xr is the normalized wind speed threshold for the sand–dust storm. X is represented by a random signal with a normal Gaussian distribution. The storms occur when X ≥ Xr. From this model, the time interval distribution of N = Aexp(−bt) can be deduced, wherein N is the number of time intervals with length greater than t, A and b are constants, and b is related to Xr. In this study, sand–dust storm data recorded in spring at the Yanchi meteorological station in China were analysed to verify whether the time interval distribution of the sand–dust storms agrees with the above time interval distribution. We found that the distribution of the time interval between successive sand–dust storms in April agrees well with the above exponential equation. However, the interval distribution for the sand–dust storm data for the entire spring period displayed a better fit to the Weibull equation and depended on the variation of the sand–dust storm threshold wind speed. (paper)

  8. Design of time interval generator based on hybrid counting method

    International Nuclear Information System (INIS)

    Yao, Yuan; Wang, Zhaoqi; Lu, Houbing; Chen, Lian; Jin, Ge

    2016-01-01

    Time Interval Generators (TIGs) are frequently used for the characterizations or timing operations of instruments in particle physics experiments. Though some “off-the-shelf” TIGs can be employed, the necessity of a custom test system or control system makes the TIGs, being implemented in a programmable device desirable. Nowadays, the feasibility of using Field Programmable Gate Arrays (FPGAs) to implement particle physics instrumentation has been validated in the design of Time-to-Digital Converters (TDCs) for precise time measurement. The FPGA-TDC technique is based on the architectures of Tapped Delay Line (TDL), whose delay cells are down to few tens of picosecond. In this case, FPGA-based TIGs with high delay step are preferable allowing the implementation of customized particle physics instrumentations and other utilities on the same FPGA device. A hybrid counting method for designing TIGs with both high resolution and wide range is presented in this paper. The combination of two different counting methods realizing an integratable TIG is described in detail. A specially designed multiplexer for tap selection is emphatically introduced. The special structure of the multiplexer is devised for minimizing the different additional delays caused by the unpredictable routings from different taps to the output. A Kintex-7 FPGA is used for the hybrid counting-based implementation of a TIG, providing a resolution up to 11 ps and an interval range up to 8 s.

  9. Design of time interval generator based on hybrid counting method

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Yuan [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Wang, Zhaoqi [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Lu, Houbing [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hefei Electronic Engineering Institute, Hefei 230037 (China); Chen, Lian [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China); Jin, Ge, E-mail: goldjin@ustc.edu.cn [State Key Laboratory of Particle Detection and Electronics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2016-10-01

    Time Interval Generators (TIGs) are frequently used for the characterizations or timing operations of instruments in particle physics experiments. Though some “off-the-shelf” TIGs can be employed, the necessity of a custom test system or control system makes the TIGs, being implemented in a programmable device desirable. Nowadays, the feasibility of using Field Programmable Gate Arrays (FPGAs) to implement particle physics instrumentation has been validated in the design of Time-to-Digital Converters (TDCs) for precise time measurement. The FPGA-TDC technique is based on the architectures of Tapped Delay Line (TDL), whose delay cells are down to few tens of picosecond. In this case, FPGA-based TIGs with high delay step are preferable allowing the implementation of customized particle physics instrumentations and other utilities on the same FPGA device. A hybrid counting method for designing TIGs with both high resolution and wide range is presented in this paper. The combination of two different counting methods realizing an integratable TIG is described in detail. A specially designed multiplexer for tap selection is emphatically introduced. The special structure of the multiplexer is devised for minimizing the different additional delays caused by the unpredictable routings from different taps to the output. A Kintex-7 FPGA is used for the hybrid counting-based implementation of a TIG, providing a resolution up to 11 ps and an interval range up to 8 s.

  10. Dimensional Stability of Two Polyvinyl Siloxane Impression Materials in Different Time Intervals

    Directory of Open Access Journals (Sweden)

    Aalaei Sh

    2015-12-01

    Full Text Available Statement of the Problem: Dental prosthesis is usually made indirectly; there- fore dimensional stability of the impression material is very important. Every few years, new impression materials with different manufacturers’ claims regarding their better properties are introduced to the dental markets which require more research to evaluate their true dimensional changes. Objectives: The aim of this study was to evaluate dimensional stability of additional silicone impression material (Panasil® and Affinis® in different time intervals. Materials and Methods: In this experimental study, using two additional silicones (Panasil® and Affinis®, we made sixty impressions of standard die in similar conditions of 23 °C and 59% relative humidity by a special tray. The die included three horizontal and two vertical lines that were parallel. The vertical line crossed the horizontal ones at a point that served as reference for measurement. All impressions were poured with high strength dental stone. The dimensions were measured by stereo-microscope by two examiners in three interval storage times (1, 24 and 168 hours.The data were statistically analyzed using t-test and ANOVA. Results: All of the stone casts were larger than the standard die. Dimensional changes of Panasil and Affinis were 0.07%, 0.24%, 0.27% and 0.02%, 0.07%, 0.16% after 1, 24 and 168 hours, respectively. Dimensional change for two impression materials wasn’t significant in the interval time, expect for Panasil after one week (p = 0.004. Conclusions: According to the limitations of this study, Affinis impressions were dimensionally more stable than Panasil ones, but it was not significant. Dimensional change of Panasil impression showed a statistically significant difference after one week. Dimensional changes of both impression materials were based on ADA standard limitation in all time intervals (< 0.5%; therefore, dimensional stability of this impression was accepted at least

  11. Automatic, time-interval traffic counts for recreation area management planning

    Science.gov (United States)

    D. L. Erickson; C. J. Liu; H. K. Cordell

    1980-01-01

    Automatic, time-interval recorders were used to count directional vehicular traffic on a multiple entry/exit road network in the Red River Gorge Geological Area, Daniel Boone National Forest. Hourly counts of entering and exiting traffic differed according to recorder location, but an aggregated distribution showed a delayed peak in exiting traffic thought to be...

  12. Estimation of sojourn time in chronic disease screening without data on interval cases.

    Science.gov (United States)

    Chen, T H; Kuo, H S; Yen, M F; Lai, M S; Tabar, L; Duffy, S W

    2000-03-01

    Estimation of the sojourn time on the preclinical detectable period in disease screening or transition rates for the natural history of chronic disease usually rely on interval cases (diagnosed between screens). However, to ascertain such cases might be difficult in developing countries due to incomplete registration systems and difficulties in follow-up. To overcome this problem, we propose three Markov models to estimate parameters without using interval cases. A three-state Markov model, a five-state Markov model related to regional lymph node spread, and a five-state Markov model pertaining to tumor size are applied to data on breast cancer screening in female relatives of breast cancer cases in Taiwan. Results based on a three-state Markov model give mean sojourn time (MST) 1.90 (95% CI: 1.18-4.86) years for this high-risk group. Validation of these models on the basis of data on breast cancer screening in the age groups 50-59 and 60-69 years from the Swedish Two-County Trial shows the estimates from a three-state Markov model that does not use interval cases are very close to those from previous Markov models taking interval cancers into account. For the five-state Markov model, a reparameterized procedure using auxiliary information on clinically detected cancers is performed to estimate relevant parameters. A good fit of internal and external validation demonstrates the feasibility of using these models to estimate parameters that have previously required interval cancers. This method can be applied to other screening data in which there are no data on interval cases.

  13. AN ACCURATE ORBITAL INTEGRATOR FOR THE RESTRICTED THREE-BODY PROBLEM AS A SPECIAL CASE OF THE DISCRETE-TIME GENERAL THREE-BODY PROBLEM

    International Nuclear Information System (INIS)

    Minesaki, Yukitaka

    2013-01-01

    For the restricted three-body problem, we propose an accurate orbital integration scheme that retains all conserved quantities of the two-body problem with two primaries and approximately preserves the Jacobi integral. The scheme is obtained by taking the limit as mass approaches zero in the discrete-time general three-body problem. For a long time interval, the proposed scheme precisely reproduces various periodic orbits that cannot be accurately computed by other generic integrators

  14. Infant rats can learn time intervals before the maturation of the striatum: evidence from odor fear conditioning

    Directory of Open Access Journals (Sweden)

    Julie eBoulanger Bertolus

    2014-05-01

    Full Text Available Interval timing refers to the ability to perceive, estimate and discriminate durations in the range of seconds to minutes. Very little is currently known about the ontogeny of interval timing throughout development. On the other hand, even though the neural circuit sustaining interval timing is a matter of debate, the striatum has been suggested to be an important component of the system and its maturation occurs around the third post-natal week in rats. The global aim of the present study was to investigate interval timing abilities at an age for which striatum is not yet mature. We used odor fear conditioning, as it can be applied to very young animals. In odor fear conditioning, an odor is presented to the animal and a mild footshock is delivered after a fixed interval. Adult rats have been shown to learn the temporal relationships between the odor and the shock after a few associations. The first aim of the present study was to assess the activity of the striatum during odor fear conditioning using 2-Deoxyglucose autoradiography during development in rats. The data showed that although fear learning was displayed at all tested ages, activation of the striatum was observed in adults but not in juvenile animals. Next, we assessed the presence of evidence of interval timing in ages before and after the inclusion of the striatum into the fear conditioning circuit. We used an experimental setup allowing the simultaneous recording of freezing and respiration that have been demonstrated to be sensitive to interval timing in adult rats. This enabled the detection of duration-related temporal patterns for freezing and/or respiration curves in infants as young as 12 days post-natal during odor-fear conditioning. This suggests that infants are able to encode time durations as well as and as quickly as adults while their striatum is not yet functional. Alternative networks possibly sustaining interval timing in infant rats are discussed.

  15. Dead-time corrections on long-interval measurements of short-lived activities

    International Nuclear Information System (INIS)

    Irfan, M.

    1977-01-01

    A method has been proposed to make correction for counting losses due to dead time where the counting interval is comparable to or larger than the half-life of the activity under investigation. Counts due to background and any long-lived activity present in the source have been taken into consideration. The method is, under certain circumstances, capable of providing a valuable check on the accuracy of the dead time of the counting system. (Auth.)

  16. Time-of-flight depth image enhancement using variable integration time

    Science.gov (United States)

    Kim, Sun Kwon; Choi, Ouk; Kang, Byongmin; Kim, James Dokyoon; Kim, Chang-Yeong

    2013-03-01

    Time-of-Flight (ToF) cameras are used for a variety of applications because it delivers depth information at a high frame rate. These cameras, however, suffer from challenging problems such as noise and motion artifacts. To increase signal-to-noise ratio (SNR), the camera should calculate a distance based on a large amount of infra-red light, which needs to be integrated over a long time. On the other hand, the integration time should be short enough to suppress motion artifacts. We propose a ToF depth imaging method to combine advantages of short and long integration times exploiting an imaging fusion scheme proposed for color imaging. To calibrate depth differences due to the change of integration times, a depth transfer function is estimated by analyzing the joint histogram of depths in the two images of different integration times. The depth images are then transformed into wavelet domains and fused into a depth image with suppressed noise and low motion artifacts. To evaluate the proposed method, we captured a moving bar of a metronome with different integration times. The experiment shows the proposed method could effectively remove the motion artifacts while preserving high SNR comparable to the depth images acquired during long integration time.

  17. A comparison of systolic time intervals measured by impedance cardiography and carotid pulse tracing

    DEFF Research Database (Denmark)

    Mehlsen, J; Bonde, J; Rehling, Michael

    1990-01-01

    The purpose of this study was to compare the systolic time intervals (STI) obtained by impedance cardiography and by the conventional carotid technique. This comparison was done with respect to: 1) correlations between variables obtained by the two methods, 2) ability to reflect drug-induced chan......The purpose of this study was to compare the systolic time intervals (STI) obtained by impedance cardiography and by the conventional carotid technique. This comparison was done with respect to: 1) correlations between variables obtained by the two methods, 2) ability to reflect drug...

  18. Regression analysis of case K interval-censored failure time data in the presence of informative censoring.

    Science.gov (United States)

    Wang, Peijie; Zhao, Hui; Sun, Jianguo

    2016-12-01

    Interval-censored failure time data occur in many fields such as demography, economics, medical research, and reliability and many inference procedures on them have been developed (Sun, 2006; Chen, Sun, and Peace, 2012). However, most of the existing approaches assume that the mechanism that yields interval censoring is independent of the failure time of interest and it is clear that this may not be true in practice (Zhang et al., 2007; Ma, Hu, and Sun, 2015). In this article, we consider regression analysis of case K interval-censored failure time data when the censoring mechanism may be related to the failure time of interest. For the problem, an estimated sieve maximum-likelihood approach is proposed for the data arising from the proportional hazards frailty model and for estimation, a two-step procedure is presented. In the addition, the asymptotic properties of the proposed estimators of regression parameters are established and an extensive simulation study suggests that the method works well. Finally, we apply the method to a set of real interval-censored data that motivated this study. © 2016, The International Biometric Society.

  19. Verified Interval Orbit Propagation in Satellite Collision Avoidance

    NARCIS (Netherlands)

    Römgens, B.A.; Mooij, E.; Naeije, M.C.

    2011-01-01

    Verified interval integration methods enclose a solution set corresponding to interval initial values and parameters, and bound integration and rounding errors. Verified methods suffer from overestimation of the solution, i.e., non-solutions are also included in the solution enclosure. Two verified

  20. Pre-hospital care time intervals among victims of road traffic injuries in Iran. A cross-sectional study

    Directory of Open Access Journals (Sweden)

    Bigdeli Maryam

    2010-07-01

    Full Text Available Abstract Background Road traffic injuries (RTIs are a major public health problem, requiring concerted efforts both for their prevention and a reduction of their consequences. Timely arrival of the Emergency Medical Service (EMS at the crash scene followed by speedy victim transportation by trained personnel may reduce the RTIs' consequences. The first 60 minutes after injury occurrence - referred to as the "golden hour"- are vital for the saving of lives. The present study was designed to estimate the average of various time intervals occurring during the pre-hospital care process and to examine the differences between these time intervals as regards RTIs on urban and interurban roads. Method A retrospective cross-sectional study was designed and various time intervals in relation to pre-hospital care of RTIs identified in the ambulance dispatch centre in Urmia, Iran from 20 March 2005 to 20 March 2007. All cases which resulted in ambulance dispatches were reviewed and those that had complete data on time intervals were analyzed. Results In total, the cases of 2027 RTI victims were analysed. Of these, 61.5 % of the subjects were injured in city areas. The mean response time for city locations was 5.0 minutes, compared with 10.6 minutes for interurban road locations. The mean on-scene time on the interurban roads was longer than on city roads (9.2 vs. 6.1 minutes, p Conclusion The response, transport and total time intervals among EMS responding to RTI incidents were longer for interurban roads, compared to the city areas. More research should take place on needs-to and access-for EMS on city and interurban roads. The notification interval seems to be a hidden part of the post-crash events and indirectly affects the "golden hour" for victim management and it needs to be measured through the establishment of the surveillance systems.

  1. [Processing acoustically presented time intervals of seconds duration: an expression of the phonological loop of the working memory?].

    Science.gov (United States)

    Grube, D

    1996-01-01

    Working memory has been proposed to contribute to the processing of time, rhythm and music; the question which component of working memory is involved is under discussion. The present study tests the hypothesis that the phonological loop component (Baddeley, 1986) is involved in the processing of auditorily presented time intervals of a few seconds' duration. Typical effects well known with short-term retention of verbal material could be replicated with short-term retention of temporal intervals: The immediate reproduction of time intervals was impaired under conditions of background music and articulatory suppression. Neither the accuracy nor the speed of responses in a (non-phonological) mental rotation task were diminished under these conditions. Processing of auditorily presented time intervals seems to be constrained by the capacity of the phonological loop: The immediate serial recall of sequences of time intervals was shown to be related to the immediate serial recall of words (memory span). The results confirm the notion that working memory resources, and especially the phonological loop component, underlie the processing of auditorily presented temporal information with a duration of a few seconds.

  2. Designing Yellow Intervals for Rainy and Wet Roadway Conditions

    Directory of Open Access Journals (Sweden)

    Huan Li

    2012-06-01

    Full Text Available The research presented in this paper quantifies and models the impact of wet pavement surface and rainy weather conditions on driver perception-reaction times (PRTs, deceleration levels, and traffic signal change interval durations. A total of 648 stop-run records were collected as part of the research effort for a 72 km/h (45 mi/h approach speed where participant drivers encountered a yellow indication initiation at different distances from the intersection. The participant drivers were randomly selected in different age groups (under 40 years old, 40 to 59 years old, and 60 years of age or older and genders (female and male. Using the gathered data, statistical models for driver PRT and deceleration levels were developed, considering roadway surface and environmental parameters, driver attributes (age and gender, roadway grade, approaching speed, and time and distance to the intersection at the onset of yellow. Inclement weather yellow timings were then developed and summarized in lookup tables as a function of different factors (driver age/gender, roadway grade, speed limit, precipitation level, and roadway surface condition to provide practical guidelines for the design of yellow signal timings in wet and rainy weather conditions. The results indicate that wet roadway surface conditions require a 5 percent increase in the change interval and that rainy conditions require a 10 percent or more increase in the duration of the change interval. These recommended change durations can also be integrated within the Vehicle Infrastructure Integration (VII initiative to provide customizable driver warnings prior to a transition to a red indication.

  3. A new variable interval schedule with constant hazard rate and finite time range.

    Science.gov (United States)

    Bugallo, Mehdi; Machado, Armando; Vasconcelos, Marco

    2018-05-27

    We propose a new variable interval (VI) schedule that achieves constant probability of reinforcement in time while using a bounded range of intervals. By sampling each trial duration from a uniform distribution ranging from 0 to 2 T seconds, and then applying a reinforcement rule that depends linearly on trial duration, the schedule alternates reinforced and unreinforced trials, each less than 2 T seconds, while preserving a constant hazard function. © 2018 Society for the Experimental Analysis of Behavior.

  4. Properties of Asymmetric Detrended Fluctuation Analysis in the time series of RR intervals

    Science.gov (United States)

    Piskorski, J.; Kosmider, M.; Mieszkowski, D.; Krauze, T.; Wykretowicz, A.; Guzik, P.

    2018-02-01

    Heart rate asymmetry is a phenomenon by which the accelerations and decelerations of heart rate behave differently, and this difference is consistent and unidirectional, i.e. in most of the analyzed recordings the inequalities have the same directions. So far, it has been established for variance and runs based types of descriptors of RR intervals time series. In this paper we apply the newly developed method of Asymmetric Detrended Fluctuation Analysis, which so far has mainly been used with economic time series, to the set of 420 stationary 30 min time series of RR intervals from young, healthy individuals aged between 20 and 40. This asymmetric approach introduces separate scaling exponents for rising and falling trends. We systematically study the presence of asymmetry in both global and local versions of this method. In this study global means "applying to the whole time series" and local means "applying to windows jumping along the recording". It is found that the correlation structure of the fluctuations left over after detrending in physiological time series shows strong asymmetric features in both magnitude, with α+ physiological data after shuffling or with a group of symmetric synthetic time series.

  5. Method to measure autonomic control of cardiac function using time interval parameters from impedance cardiography

    International Nuclear Information System (INIS)

    Meijer, Jan H; Boesveldt, Sanne; Elbertse, Eskeline; Berendse, H W

    2008-01-01

    The time difference between the electrocardiogram and impedance cardiogram can be considered as a measure for the time delay between the electrical and mechanical activities of the heart. This time interval, characterized by the pre-ejection period (PEP), is related to the sympathetic autonomous nervous control of cardiac activity. PEP, however, is difficult to measure in practice. Therefore, a novel parameter, the initial systolic time interval (ISTI), is introduced to provide a more practical measure. The use of ISTI instead of PEP was evaluated in three groups: young healthy subjects, patients with Parkinson's disease, and a group of elderly, healthy subjects of comparable age. PEP and ISTI were studied under two conditions: at rest and after an exercise stimulus. Under both conditions, PEP and ISTI behaved largely similarly in the three groups and were significantly correlated. It is concluded that ISTI can be used as a substitute for PEP and, therefore, to evaluate autonomic neuropathy both in clinical and extramural settings. Measurement of ISTI can also be used to non-invasively monitor the electromechanical cardiac time interval, and the associated autonomic activity, under physiological circumstances

  6. Corticostriatal field potentials are modulated at delta and theta frequencies during interval-timing task in rodents

    Directory of Open Access Journals (Sweden)

    Eric B Emmons

    2016-04-01

    Full Text Available Organizing movements in time is a critical and highly conserved feature of mammalian behavior. Temporal control of action requires corticostriatal networks. We investigate these networks in rodents using a two-interval timing task while recording local field potentials in medial frontal cortex or dorsomedial striatum. Consistent with prior work, we found cue-triggered delta (1-4 Hz and theta activity (4-8 Hz primarily in rodent medial frontal cortex. We observed delta activity across temporal intervals in medial frontal cortex and dorsomedial striatum. Rewarded responses were associated with increased delta activity in medial frontal cortex. Activity in theta bands in medial frontal cortex and delta bands in the striatum was linked with the timing of responses. These data suggest both delta and theta activity in frontostriatal networks are modulated during interval timing and that activity in these bands may be involved in the temporal control of action.

  7. Pre-hospital care time intervals among victims of road traffic injuries in Iran. A cross-sectional study.

    Science.gov (United States)

    Bigdeli, Maryam; Khorasani-Zavareh, Davoud; Mohammadi, Reza

    2010-07-09

    Road traffic injuries (RTIs) are a major public health problem, requiring concerted efforts both for their prevention and a reduction of their consequences. Timely arrival of the Emergency Medical Service (EMS) at the crash scene followed by speedy victim transportation by trained personnel may reduce the RTIs' consequences. The first 60 minutes after injury occurrence--referred to as the "golden hour"--are vital for the saving of lives. The present study was designed to estimate the average of various time intervals occurring during the pre-hospital care process and to examine the differences between these time intervals as regards RTIs on urban and interurban roads. A retrospective cross-sectional study was designed and various time intervals in relation to pre-hospital care of RTIs identified in the ambulance dispatch centre in Urmia, Iran from 20 March 2005 to 20 March 2007. All cases which resulted in ambulance dispatches were reviewed and those that had complete data on time intervals were analyzed. In total, the cases of 2027 RTI victims were analysed. Of these, 61.5% of the subjects were injured in city areas. The mean response time for city locations was 5.0 minutes, compared with 10.6 minutes for interurban road locations. The mean on-scene time on the interurban roads was longer than on city roads (9.2 vs. 6.1 minutes, p transport times from the scene to the hospital were also significantly longer for interurban incidents (17.1 vs. 6.3 minutes, p transport and total time intervals among EMS responding to RTI incidents were longer for interurban roads, compared to the city areas. More research should take place on needs-to and access-for EMS on city and interurban roads. The notification interval seems to be a hidden part of the post-crash events and indirectly affects the "golden hour" for victim management and it needs to be measured through the establishment of the surveillance systems.

  8. Robust stability of interval bidirectional associative memory neural network with time delays.

    Science.gov (United States)

    Liao, Xiaofeng; Wong, Kwok-wo

    2004-04-01

    In this paper, the conventional bidirectional associative memory (BAM) neural network with signal transmission delay is intervalized in order to study the bounded effect of deviations in network parameters and external perturbations. The resultant model is referred to as a novel interval dynamic BAM (IDBAM) model. By combining a number of different Lyapunov functionals with the Razumikhin technique, some sufficient conditions for the existence of unique equilibrium and robust stability are derived. These results are fairly general and can be verified easily. To go further, we extend our investigation to the time-varying delay case. Some robust stability criteria for BAM with perturbations of time-varying delays are derived. Besides, our approach for the analysis allows us to consider several different types of activation functions, including piecewise linear sigmoids with bounded activations as well as the usual C1-smooth sigmoids. We believe that the results obtained have leading significance in the design and application of BAM neural networks.

  9. An arbitrary-order staggered time integrator for the linear acoustic wave equation

    Science.gov (United States)

    Lee, Jaejoon; Park, Hyunseo; Park, Yoonseo; Shin, Changsoo

    2018-02-01

    We suggest a staggered time integrator whose order of accuracy can arbitrarily be extended to solve the linear acoustic wave equation. A strategy to select the appropriate order of accuracy is also proposed based on the error analysis that quantitatively predicts the truncation error of the numerical solution. This strategy not only reduces the computational cost several times, but also allows us to flexibly set the modelling parameters such as the time step length, grid interval and P-wave speed. It is demonstrated that the proposed method can almost eliminate temporal dispersive errors during long term simulations regardless of the heterogeneity of the media and time step lengths. The method can also be successfully applied to the source problem with an absorbing boundary condition, which is frequently encountered in the practical usage for the imaging algorithms or the inverse problems.

  10. Self-produced Time Intervals Are Perceived as More Variable and/or Shorter Depending on Temporal Context in Subsecond and Suprasecond Ranges

    Directory of Open Access Journals (Sweden)

    Keita eMitani

    2016-06-01

    Full Text Available The processing of time intervals is fundamental for sensorimotor and cognitive functions. Perceptual and motor timing are often performed concurrently (e.g., playing a musical instrument. Although previous studies have shown the influence of body movements on time perception, how we perceive self-produced time intervals has remained unclear. Furthermore, it has been suggested that the timing mechanisms are distinct for the sub- and suprasecond ranges. Here, we compared perceptual performances for self-produced and passively presented time intervals in random contexts (i.e., multiple target intervals presented in a session across the sub- and suprasecond ranges (Experiment 1 and within the sub- (Experiment 2 and suprasecond (Experiment 3 ranges, and in a constant context (i.e., a single target interval presented in a session in the sub- and suprasecond ranges (Experiment 4. We show that self-produced time intervals were perceived as shorter and more variable across the sub- and suprasecond ranges and within the suprasecond range but not within the subsecond range in a random context. In a constant context, the self-produced time intervals were perceived as more variable in the suprasecond range but not in the subsecond range. The impairing effects indicate that motor timing interferes with perceptual timing. The dependence of impairment on temporal contexts suggests multiple timing mechanisms for the subsecond and suprasecond ranges. In addition, violation of the scalar property (i.e., a constant variability to target interval ratio was observed between the sub- and suprasecond ranges. The violation was clearer for motor timing than for perceptual timing. This suggests that the multiple timing mechanisms for the sub- and suprasecond ranges overlap more for perception than for motor. Moreover, the central tendency effect (i.e., where shorter base intervals are overestimated and longer base intervals are underestimated disappeared with subsecond

  11. Discrete time interval measurement system: fundamentals, resolution and errors in the measurement of angular vibrations

    International Nuclear Information System (INIS)

    Gómez de León, F C; Meroño Pérez, P A

    2010-01-01

    The traditional method for measuring the velocity and the angular vibration in the shaft of rotating machines using incremental encoders is based on counting the pulses at given time intervals. This method is generically called the time interval measurement system (TIMS). A variant of this method that we have developed in this work consists of measuring the corresponding time of each pulse from the encoder and sampling the signal by means of an A/D converter as if it were an analog signal, that is to say, in discrete time. For this reason, we have denominated this method as the discrete time interval measurement system (DTIMS). This measurement system provides a substantial improvement in the precision and frequency resolution compared with the traditional method of counting pulses. In addition, this method permits modification of the width of some pulses in order to obtain a mark-phase on every lap. This paper explains the theoretical fundamentals of the DTIMS and its application for measuring the angular vibrations of rotating machines. It also displays the required relationship between the sampling rate of the signal, the number of pulses of the encoder and the rotating velocity in order to obtain the required resolution and to delimit the methodological errors in the measurement

  12. Tonic and Phasic Dopamine Fluctuations as Reflected in Beta-power Predict Interval Timing Behavior

    NARCIS (Netherlands)

    Kononowicz, Tadeusz; van Rijn, Hedderik

    It has been repeatedly shown that dopamine impacts interval timing in humans and animals (for a review, see Coull, Cheng, & Meck, 2012). Particularly, administration of dopamine agonists or antagonists speeds-up or slows down internal passage of time, respectively (Meck, 1996). This co-variations in

  13. Determination and identification of naturally occurring decay series using milli-second order pulse time interval analysis (TIA)

    International Nuclear Information System (INIS)

    Hashimoto, T.; Sanada, Y.; Uezu, Y.

    2003-01-01

    A delayed coincidence method, called a time interval analysis (TIA) method, has been successfully applied to selective determination of the correlated α-α decay events in millisecond order life-time. A main decay process applicable to TIA-treatment is 220 Rn → 216 Po(T 1/2 :145ms) → {Th-series}. The TIA is fundamentally based on the difference of time interval distribution between non-correlated decay events and other events such as background or random events when they were compiled the time interval data within a fixed time (for example, a tenth of concerned half lives). The sensitivity of the TIA-analysis due to correlated α-α decay events could be subsequently improved in respect of background elimination using the pulse shape discrimination technique (PSD with PERALS counter) to reject β/γ-pulses, purging of nitrogen gas into extra scintillator, and applying solvent extraction of Ra. (author)

  14. Usability of a new multiple high-speed pulse time data registration, processing and real-time display system for pulse time interval analysis

    International Nuclear Information System (INIS)

    Yawata, Takashi; Sakaue, Hisanobu; Hashimoto, Tetsuo; Itou, Shigeki

    2006-01-01

    A new high-speed multiple pulse time data registration, processing and real-time display system for time interval analysis (TIA) was developed for counting either β-α or α-α correlated decay-events. The TIA method has been so far limited to selective extraction of successive α-α decay events within the milli-second time scale owing to the use of original electronic hardware. In the present pulse-processing system, three different high-speed α/β(γ) pulses could be fed quickly to original 32 bit PCI board (ZN-HTS2) within 1 μs. This original PCI board is consisting of a timing-control IC (HTS-A) and 28 bit counting IC (HTS-B). All channel and pulse time data were stored to FIFO RAM, followed to transfer into temporary CPU RAM (32 MB) by DMA. Both data registration (into main RAM (200 MB)) and calculation of pulse time intervals together with real-time TIA-distribution display simultaneously processed using two sophisticate softwares. The present system has proven to succeed for the real-time display of TIA distribution spectrum even when 1.6x10 5 cps pulses from pulse generator were given to the system. By using this new system combined with liquid scintillation counting (LSC) apparatus, both a natural micro-second order β-α correlated decay-events and a milli-second order α-α correlated decay-event could be selectively extracted from the mixture of natural radionuclides. (author)

  15. Efficient Estimation for Diffusions Sampled at High Frequency Over a Fixed Time Interval

    DEFF Research Database (Denmark)

    Jakobsen, Nina Munkholt; Sørensen, Michael

    Parametric estimation for diffusion processes is considered for high frequency observations over a fixed time interval. The processes solve stochastic differential equations with an unknown parameter in the diffusion coefficient. We find easily verified conditions on approximate martingale...

  16. Optimization of Allowed Outage Time and Surveillance Test Intervals

    Energy Technology Data Exchange (ETDEWEB)

    Al-Dheeb, Mujahed; Kang, Sunkoo; Kim, Jonghyun [KEPCO international nuclear graduate school, Ulsan (Korea, Republic of)

    2015-10-15

    The primary purpose of surveillance testing is to assure that the components of standby safety systems will be operable when they are needed in an accident. By testing these components, failures can be detected that may have occurred since the last test or the time when the equipment was last known to be operational. The probability a system or system component performs a specified function or mission under given conditions at a prescribed time is called availability (A). Unavailability (U) as a risk measure is just the complementary probability to A(t). The increase of U means the risk is increased as well. D and T have an important impact on components, or systems, unavailability. The extension of D impacts the maintenance duration distributions for at-power operations, making them longer. This, in turn, increases the unavailability due to maintenance in the systems analysis. As for T, overly-frequent surveillances can result in high system unavailability. This is because the system may be taken out of service often due to the surveillance itself and due to the repair of test-caused failures of the component. The test-caused failures include those incurred by wear and tear of the component due to the surveillances. On the other hand, as the surveillance interval increases, the component's unavailability will grow because of increased occurrences of time-dependent random failures. In that situation, the component cannot be relied upon, and accordingly the system unavailability will increase. Thus, there should be an optimal component surveillance interval in terms of the corresponding system availability. This paper aims at finding the optimal T and D which result in minimum unavailability which in turn reduces the risk. Applying the methodology in section 2 to find the values of optimal T and D for two components, i.e., safety injection pump (SIP) and turbine driven aux feedwater pump (TDAFP). Section 4 is addressing interaction between D and T. In general

  17. Optimization of Allowed Outage Time and Surveillance Test Intervals

    International Nuclear Information System (INIS)

    Al-Dheeb, Mujahed; Kang, Sunkoo; Kim, Jonghyun

    2015-01-01

    The primary purpose of surveillance testing is to assure that the components of standby safety systems will be operable when they are needed in an accident. By testing these components, failures can be detected that may have occurred since the last test or the time when the equipment was last known to be operational. The probability a system or system component performs a specified function or mission under given conditions at a prescribed time is called availability (A). Unavailability (U) as a risk measure is just the complementary probability to A(t). The increase of U means the risk is increased as well. D and T have an important impact on components, or systems, unavailability. The extension of D impacts the maintenance duration distributions for at-power operations, making them longer. This, in turn, increases the unavailability due to maintenance in the systems analysis. As for T, overly-frequent surveillances can result in high system unavailability. This is because the system may be taken out of service often due to the surveillance itself and due to the repair of test-caused failures of the component. The test-caused failures include those incurred by wear and tear of the component due to the surveillances. On the other hand, as the surveillance interval increases, the component's unavailability will grow because of increased occurrences of time-dependent random failures. In that situation, the component cannot be relied upon, and accordingly the system unavailability will increase. Thus, there should be an optimal component surveillance interval in terms of the corresponding system availability. This paper aims at finding the optimal T and D which result in minimum unavailability which in turn reduces the risk. Applying the methodology in section 2 to find the values of optimal T and D for two components, i.e., safety injection pump (SIP) and turbine driven aux feedwater pump (TDAFP). Section 4 is addressing interaction between D and T. In general

  18. Electric power demand forecasting using interval time series. A comparison between VAR and iMLP

    International Nuclear Information System (INIS)

    Garcia-Ascanio, Carolina; Mate, Carlos

    2010-01-01

    Electric power demand forecasts play an essential role in the electric industry, as they provide the basis for making decisions in power system planning and operation. A great variety of mathematical methods have been used for demand forecasting. The development and improvement of appropriate mathematical tools will lead to more accurate demand forecasting techniques. In order to forecast the monthly electric power demand per hour in Spain for 2 years, this paper presents a comparison between a new forecasting approach considering vector autoregressive (VAR) forecasting models applied to interval time series (ITS) and the iMLP, the multi-layer perceptron model adapted to interval data. In the proposed comparison, for the VAR approach two models are fitted per every hour, one composed of the centre (mid-point) and radius (half-range), and another one of the lower and upper bounds according to the interval representation assumed by the ITS in the learning set. In the case of the iMLP, only the model composed of the centre and radius is fitted. The other interval representation composed of the lower and upper bounds is obtained from the linear combination of the two. This novel approach, obtaining two bivariate models each hour, makes possible to establish, for different periods in the day, which interval representation is more accurate. Furthermore, the comparison between two different techniques adapted to interval time series allows us to determine the efficiency of these models in forecasting electric power demand. It is important to note that the iMLP technique has been selected for the comparison, as it has shown its accuracy in forecasting daily electricity price intervals. This work shows the ITS forecasting methods as a potential tool that will lead to a reduction in risk when making power system planning and operational decisions. (author)

  19. Assessing cardiac preload by the Initial Systolic Time Interval obtained from impedance cardiography

    Directory of Open Access Journals (Sweden)

    Jan H Meijer

    2010-01-01

    Full Text Available The Initial Systolic Time Interval (ISTI, obtained from the electrocardiogram (ECG and impedance cardiogram (ICG, is considered to be a measure for the time delay between the electrical and mechanical activity of the heart and reflects an early active period of the cardiac cycle. The clinical relevance of this time interval is subject of study. This paper presents preliminary results of a pilot study investigating the use of ISTI in evaluating and predicting the circulatory response to fluid administration in patients after coronary artery bypass graft surgery, by comparing ISTI with cardiac output (CO responsiveness. Also the use of the pulse transit time (PTT, earlier recommended for this purpose, is investigated. The results show an inverse relationship between ISTI and CO at all moments of fluid administration and also an inverse relationship between the changes ΔISTI and ΔCO before and after full fluid administration. No relationships between PTT and CO or ΔPTT and ΔCO were found. It is concluded that ISTI is dependent upon preload, and that ISTI has the potential to be used as a clinical parameter assessing preload.

  20. Evaluation of downmotion time interval molten materials to core catcher during core disruptive accidents postulated in LMFR

    International Nuclear Information System (INIS)

    Voronov, S.A.; Kiryushin, A.I.; Kuzavkov, N.G.; Vlasichev, G.N.

    1994-01-01

    Hypothetical core disruptive accidents are postulated to clear potential of a reactor plant to withstand extreme conditions and to generate measures for management and mitigation of accidents consequence. In Russian advanced reactors there is a core catcher below the diagrid to prevent vessel bottom melting and to localize fuel debris. In this paper the calculation technique and estimation of relocation time of molten fuel and materials are presented in the case of core disruptive accidents postulated for LMFR reactor. To evaluate minimum interval of fuel relocation time the calculations for different initial data are provided. Large mass of materials between the core and the catcher in LMFR reactor hinders molten materials relocation toward the vessel bottom. That condition increases the time interval of reaching core catcher by molten fuel. Computations performed allowed to evaluate the minimum molten materials relocation time from the core to the core catcher. This time interval is in a range of 3.5-5.5 hours. (author)

  1. RISMA: A Rule-based Interval State Machine Algorithm for Alerts Generation, Performance Analysis and Monitoring Real-Time Data Processing

    Science.gov (United States)

    Laban, Shaban; El-Desouky, Aly

    2013-04-01

    The monitoring of real-time systems is a challenging and complicated process. So, there is a continuous need to improve the monitoring process through the use of new intelligent techniques and algorithms for detecting exceptions, anomalous behaviours and generating the necessary alerts during the workflow monitoring of such systems. The interval-based or period-based theorems have been discussed, analysed, and used by many researches in Artificial Intelligence (AI), philosophy, and linguistics. As explained by Allen, there are 13 relations between any two intervals. Also, there have also been many studies of interval-based temporal reasoning and logics over the past decades. Interval-based theorems can be used for monitoring real-time interval-based data processing. However, increasing the number of processed intervals makes the implementation of such theorems a complex and time consuming process as the relationships between such intervals are increasing exponentially. To overcome the previous problem, this paper presents a Rule-based Interval State Machine Algorithm (RISMA) for processing, monitoring, and analysing the behaviour of interval-based data, received from real-time sensors. The proposed intelligent algorithm uses the Interval State Machine (ISM) approach to model any number of interval-based data into well-defined states as well as inferring them. An interval-based state transition model and methodology are presented to identify the relationships between the different states of the proposed algorithm. By using such model, the unlimited number of relationships between similar large numbers of intervals can be reduced to only 18 direct relationships using the proposed well-defined states. For testing the proposed algorithm, necessary inference rules and code have been designed and applied to the continuous data received in near real-time from the stations of International Monitoring System (IMS) by the International Data Centre (IDC) of the Preparatory

  2. Robust L2-L∞ Filtering of Time-Delay Jump Systems with Respect to the Finite-Time Interval

    Directory of Open Access Journals (Sweden)

    Shuping He

    2011-01-01

    Full Text Available This paper studied the problem of stochastic finite-time boundedness and disturbance attenuation for a class of linear time-delayed systems with Markov jumping parameters. Sufficient conditions are provided to solve this problem. The L2-L∞ filters are, respectively, designed for time-delayed Markov jump linear systems with/without uncertain parameters such that the resulting filtering error dynamic system is stochastically finite-time bounded and has the finite-time interval disturbance attenuation γ for all admissible uncertainties, time delays, and unknown disturbances. By using stochastic Lyapunov-Krasovskii functional approach, it is shown that the filter designing problem is in terms of the solutions of a set of coupled linear matrix inequalities. Simulation examples are included to demonstrate the potential of the proposed results.

  3. Improved Criteria on Delay-Dependent Stability for Discrete-Time Neural Networks with Interval Time-Varying Delays

    Directory of Open Access Journals (Sweden)

    O. M. Kwon

    2012-01-01

    Full Text Available The purpose of this paper is to investigate the delay-dependent stability analysis for discrete-time neural networks with interval time-varying delays. Based on Lyapunov method, improved delay-dependent criteria for the stability of the networks are derived in terms of linear matrix inequalities (LMIs by constructing a suitable Lyapunov-Krasovskii functional and utilizing reciprocally convex approach. Also, a new activation condition which has not been considered in the literature is proposed and utilized for derivation of stability criteria. Two numerical examples are given to illustrate the effectiveness of the proposed method.

  4. Detection of abnormal item based on time intervals for recommender systems.

    Science.gov (United States)

    Gao, Min; Yuan, Quan; Ling, Bin; Xiong, Qingyu

    2014-01-01

    With the rapid development of e-business, personalized recommendation has become core competence for enterprises to gain profits and improve customer satisfaction. Although collaborative filtering is the most successful approach for building a recommender system, it suffers from "shilling" attacks. In recent years, the research on shilling attacks has been greatly improved. However, the approaches suffer from serious problem in attack model dependency and high computational cost. To solve the problem, an approach for the detection of abnormal item is proposed in this paper. In the paper, two common features of all attack models are analyzed at first. A revised bottom-up discretized approach is then proposed based on time intervals and the features for the detection. The distributions of ratings in different time intervals are compared to detect anomaly based on the calculation of chi square distribution (χ(2)). We evaluated our approach on four types of items which are defined according to the life cycles of these items. The experimental results show that the proposed approach achieves a high detection rate with low computational cost when the number of attack profiles is more than 15. It improves the efficiency in shilling attacks detection by narrowing down the suspicious users.

  5. Detection of Abnormal Item Based on Time Intervals for Recommender Systems

    Directory of Open Access Journals (Sweden)

    Min Gao

    2014-01-01

    Full Text Available With the rapid development of e-business, personalized recommendation has become core competence for enterprises to gain profits and improve customer satisfaction. Although collaborative filtering is the most successful approach for building a recommender system, it suffers from “shilling” attacks. In recent years, the research on shilling attacks has been greatly improved. However, the approaches suffer from serious problem in attack model dependency and high computational cost. To solve the problem, an approach for the detection of abnormal item is proposed in this paper. In the paper, two common features of all attack models are analyzed at first. A revised bottom-up discretized approach is then proposed based on time intervals and the features for the detection. The distributions of ratings in different time intervals are compared to detect anomaly based on the calculation of chi square distribution (χ2. We evaluated our approach on four types of items which are defined according to the life cycles of these items. The experimental results show that the proposed approach achieves a high detection rate with low computational cost when the number of attack profiles is more than 15. It improves the efficiency in shilling attacks detection by narrowing down the suspicious users.

  6. A new criterion for global robust stability of interval neural networks with discrete time delays

    International Nuclear Information System (INIS)

    Li Chuandong; Chen Jinyu; Huang Tingwen

    2007-01-01

    This paper further studies global robust stability of a class of interval neural networks with discrete time delays. By introducing an equivalent transformation of interval matrices, a new criterion on global robust stability is established. In comparison with the results reported in the literature, the proposed approach leads to results with less restrictive conditions. Numerical examples are also worked through to illustrate our results

  7. Steffensen's Integral Inequality on Time Scales

    Directory of Open Access Journals (Sweden)

    Ozkan Umut Mutlu

    2007-01-01

    Full Text Available We establish generalizations of Steffensen's integral inequality on time scales via the diamond- dynamic integral, which is defined as a linear combination of the delta and nabla integrals.

  8. The Perforation-Operation time Interval; An Important Mortality Indicator in Peptic Ulcer Perforation.

    Science.gov (United States)

    Surapaneni, Sushama; S, Rajkumar; Reddy A, Vijaya Bhaskar

    2013-05-01

    To find out the significance of the Perforation-Operation Interval (POI) with respect to an early prognosis, in patients with peritonitis which is caused by peptic ulcer perforation. Case series. Place and Duration of the Study: Department of General Surgery, Konaseema Institute of Medical Sciences and RF Amalapuram, Andhra Pradesh, India from 2008-2011. This study included 150 patients with generalized peritonitis, who were diagnosed to have Perforated Peptic Ulcers (PPUs). The diagnosis of the PPUs was established on the basis of the history , the clinical examination and the radiological findings. The perforation-operation interval was calculated from the time of onset of the symptoms like severe abdominal pain or vomiting till the time the patient was operated. Out of the 150 patients 134 were males and 16 were females, with a male : female ratio of 9:1. Their ages ranged between 25-70 years. Out of the 150 patients, 65 patients (43.3%) presented within 24 hours of the onset of severe abdominal pain (Group A), 27 patients (18%) presented between 24-48 hours of the onset of severe abdominal pain (Group B) and 58 patients (38.6%) presented after 48 hours. There was no mortality in Group A and the morbidity was more in Group B and Group C. There were 15 deaths in Group C. The problem of peptic ulcer perforation with its complication, can be decreased by decreasing the perforation -operation time interval, which as per our study, appeared to be the single most important mortality and morbidity indicator in peptic ulcer perforation.

  9. Nonparametric estimation in an "illness-death" model when all transition times are interval censored

    DEFF Research Database (Denmark)

    Frydman, Halina; Gerds, Thomas; Grøn, Randi

    2013-01-01

    We develop nonparametric maximum likelihood estimation for the parameters of an irreversible Markov chain on states {0,1,2} from the observations with interval censored times of 0 → 1, 0 → 2 and 1 → 2 transitions. The distinguishing aspect of the data is that, in addition to all transition times ...

  10. Comparison of equilibrium radionuclide and contrast angiographic measurements of left ventricular peak ejection and filling rates and their time intervals

    Energy Technology Data Exchange (ETDEWEB)

    Sugrue, D.D.; Dickie, S.; Newman, H.; Myers, M.J.; Lavender, J.P.; McKenna, W.J. (Royal Postgraduate Medical School, London (UK))

    1984-10-01

    A comparison has been made of the equilibrium radionuclide and contrast angiographic estimates of normalized peak rates of ejection (PER) and filling (PFR) and their time intervals in twenty-one patients with cardiac disorders. Contrast angiographic and radionuclide measurements of left ventricular ejection fraction (LVEF), PER and PFR correlated well but time intervals correlated poorly. Mean values for radionuclide LVEF, PER and PFR were significantly lower and radionuclide time intervals were significantly longer compared to contrast angiography measurements.

  11. Heuristic algorithms for the minmax regret flow-shop problem with interval processing times.

    Science.gov (United States)

    Ćwik, Michał; Józefczyk, Jerzy

    2018-01-01

    An uncertain version of the permutation flow-shop with unlimited buffers and the makespan as a criterion is considered. The investigated parametric uncertainty is represented by given interval-valued processing times. The maximum regret is used for the evaluation of uncertainty. Consequently, the minmax regret discrete optimization problem is solved. Due to its high complexity, two relaxations are applied to simplify the optimization procedure. First of all, a greedy procedure is used for calculating the criterion's value, as such calculation is NP-hard problem itself. Moreover, the lower bound is used instead of solving the internal deterministic flow-shop. The constructive heuristic algorithm is applied for the relaxed optimization problem. The algorithm is compared with previously elaborated other heuristic algorithms basing on the evolutionary and the middle interval approaches. The conducted computational experiments showed the advantage of the constructive heuristic algorithm with regards to both the criterion and the time of computations. The Wilcoxon paired-rank statistical test confirmed this conclusion.

  12. Online evolution reconstruction from a single measurement record with random time intervals for quantum communication

    Science.gov (United States)

    Zhou, Hua; Su, Yang; Wang, Rong; Zhu, Yong; Shen, Huiping; Pu, Tao; Wu, Chuanxin; Zhao, Jiyong; Zhang, Baofu; Xu, Zhiyong

    2017-10-01

    Online reconstruction of a time-variant quantum state from the encoding/decoding results of quantum communication is addressed by developing a method of evolution reconstruction from a single measurement record with random time intervals. A time-variant two-dimensional state is reconstructed on the basis of recovering its expectation value functions of three nonorthogonal projectors from a random single measurement record, which is composed from the discarded qubits of the six-state protocol. The simulated results prove that our method is robust to typical metro quantum channels. Our work extends the Fourier-based method of evolution reconstruction from the version for a regular single measurement record with equal time intervals to a unified one, which can be applied to arbitrary single measurement records. The proposed protocol of evolution reconstruction runs concurrently with the one of quantum communication, which can facilitate the online quantum tomography.

  13. Interspike interval correlation in a stochastic exponential integrate-and-fire model with subthreshold and spike-triggered adaptation.

    Science.gov (United States)

    Shiau, LieJune; Schwalger, Tilo; Lindner, Benjamin

    2015-06-01

    We study the spike statistics of an adaptive exponential integrate-and-fire neuron stimulated by white Gaussian current noise. We derive analytical approximations for the coefficient of variation and the serial correlation coefficient of the interspike interval assuming that the neuron operates in the mean-driven tonic firing regime and that the stochastic input is weak. Our result for the serial correlation coefficient has the form of a geometric sequence and is confirmed by the comparison to numerical simulations. The theory predicts various patterns of interval correlations (positive or negative at lag one, monotonically decreasing or oscillating) depending on the strength of the spike-triggered and subthreshold components of the adaptation current. In particular, for pure subthreshold adaptation we find strong positive ISI correlations that are usually ascribed to positive correlations in the input current. Our results i) provide an alternative explanation for interspike-interval correlations observed in vivo, ii) may be useful in fitting point neuron models to experimental data, and iii) may be instrumental in exploring the role of adaptation currents for signal detection and signal transmission in single neurons.

  14. Neutron generation time of the reactor 'crocus' by an interval distribution method for counts collected by two detectors

    International Nuclear Information System (INIS)

    Haldy, P.-A.; Chikouche, M.

    1975-01-01

    The distribution is considered of time intervals between a count in one neutron detector and the consequent event registered in a second one. A 'four interval' probability generating function was derived by means of which the expression for the distribution of the time intervals, lasting from triggering detection in the first detector to subsequent count in the second, one could be obtained. The experimental work was conducted in the zero thermal power reactor Crocus, using a neutron source provided by spontaneous fission, a BF 3 counter for the first detector and an He 3 detector for the second instrument. (U.K.)

  15. Multivariate interval-censored survival data

    DEFF Research Database (Denmark)

    Hougaard, Philip

    2014-01-01

    Interval censoring means that an event time is only known to lie in an interval (L,R], with L the last examination time before the event, and R the first after. In the univariate case, parametric models are easily fitted, whereas for non-parametric models, the mass is placed on some intervals, de...

  16. Integrable Time-Dependent Quantum Hamiltonians

    Science.gov (United States)

    Sinitsyn, Nikolai A.; Yuzbashyan, Emil A.; Chernyak, Vladimir Y.; Patra, Aniket; Sun, Chen

    2018-05-01

    We formulate a set of conditions under which the nonstationary Schrödinger equation with a time-dependent Hamiltonian is exactly solvable analytically. The main requirement is the existence of a non-Abelian gauge field with zero curvature in the space of system parameters. Known solvable multistate Landau-Zener models satisfy these conditions. Our method provides a strategy to incorporate time dependence into various quantum integrable models while maintaining their integrability. We also validate some prior conjectures, including the solution of the driven generalized Tavis-Cummings model.

  17. A time-to-amplitude converter with constant fraction timing discriminators for short time interval measurements

    International Nuclear Information System (INIS)

    Kostamovaara, J.; Myllylae, R.

    1985-01-01

    The construction and the performance of a time-to-amplitude converter equipped with constant fraction discriminators is described. The TAC consists of digital and analog parts which are constructed on two printed circuit boards, both of which are located in a single width NIM module. The dead time of the TAC for a start pulse which is not followed by a stop pulse within the time range of the device (proportional100 ns) is only proportional100 ns, which enables one to avoid counting rate saturation even with a high random input signal rate. The differential and integral nonlinearities of the TAC are better than +-1.5% and 0.05%, respectively. The resolution for input timing pulses of constant shape is 20 ps (fwhm), and less than 10 ps (fwhm) with a modification in the digital part. The walk error of the constant fraction timing discriminators is presented and various parameters affecting it are discussed. The effect of the various disturbances in linearity caused by the fast ECL logic and their minimization are also discussed. The time-to-amplitude converter has been used in positron lifetime studies and for laser range finding. (orig.)

  18. Theoretical implications of quantitative properties of interval timing and probability estimation in mouse and rat.

    Science.gov (United States)

    Kheifets, Aaron; Freestone, David; Gallistel, C R

    2017-07-01

    In three experiments with mice ( Mus musculus ) and rats (Rattus norvigicus), we used a switch paradigm to measure quantitative properties of the interval-timing mechanism. We found that: 1) Rodents adjusted the precision of their timed switches in response to changes in the interval between the short and long feed latencies (the temporal goalposts). 2) The variability in the timing of the switch response was reduced or unchanged in the face of large trial-to-trial random variability in the short and long feed latencies. 3) The adjustment in the distribution of switch latencies in response to changes in the relative frequency of short and long trials was sensitive to the asymmetry in the Kullback-Leibler divergence. The three results suggest that durations are represented with adjustable precision, that they are timed by multiple timers, and that there is a trial-by-trial (episodic) record of feed latencies in memory. © 2017 Society for the Experimental Analysis of Behavior.

  19. An analyzer for pulse-interval times to study high-order effects in the processing of nuclear detector signals

    International Nuclear Information System (INIS)

    Denecke, B.; Jonge, S. de

    1998-01-01

    An electronic device to measure interval time density distributions of subsequent pulses in nuclear detectors and their electronics is described. The device has a pair-pulse resolution of 10 ns and 25 ns for 3 subsequent input signals. The conversion range is 4096 channels and the lowest channel width is 10 ns. Counter dead times, single and in series were studied and compared with the statistical model. True count rates were obtained from an exponential fit through the interval-time distribution

  20. Interval stability for complex systems

    Science.gov (United States)

    Klinshov, Vladimir V.; Kirillov, Sergey; Kurths, Jürgen; Nekorkin, Vladimir I.

    2018-04-01

    Stability of dynamical systems against strong perturbations is an important problem of nonlinear dynamics relevant to many applications in various areas. Here, we develop a novel concept of interval stability, referring to the behavior of the perturbed system during a finite time interval. Based on this concept, we suggest new measures of stability, namely interval basin stability (IBS) and interval stability threshold (IST). IBS characterizes the likelihood that the perturbed system returns to the stable regime (attractor) in a given time. IST provides the minimal magnitude of the perturbation capable to disrupt the stable regime for a given interval of time. The suggested measures provide important information about the system susceptibility to external perturbations which may be useful for practical applications. Moreover, from a theoretical viewpoint the interval stability measures are shown to bridge the gap between linear and asymptotic stability. We also suggest numerical algorithms for quantification of the interval stability characteristics and demonstrate their potential for several dynamical systems of various nature, such as power grids and neural networks.

  1. Global Robust Stability of Switched Interval Neural Networks with Discrete and Distributed Time-Varying Delays of Neural Type

    Directory of Open Access Journals (Sweden)

    Huaiqin Wu

    2012-01-01

    Full Text Available By combing the theories of the switched systems and the interval neural networks, the mathematics model of the switched interval neural networks with discrete and distributed time-varying delays of neural type is presented. A set of the interval parameter uncertainty neural networks with discrete and distributed time-varying delays of neural type are used as the individual subsystem, and an arbitrary switching rule is assumed to coordinate the switching between these networks. By applying the augmented Lyapunov-Krasovskii functional approach and linear matrix inequality (LMI techniques, a delay-dependent criterion is achieved to ensure to such switched interval neural networks to be globally asymptotically robustly stable in terms of LMIs. The unknown gain matrix is determined by solving this delay-dependent LMIs. Finally, an illustrative example is given to demonstrate the validity of the theoretical results.

  2. Tuning for temporal interval in human apparent motion detection.

    Science.gov (United States)

    Bours, Roger J E; Stuur, Sanne; Lankheet, Martin J M

    2007-01-08

    Detection of apparent motion in random dot patterns requires correlation across time and space. It has been difficult to study the temporal requirements for the correlation step because motion detection also depends on temporal filtering preceding correlation and on integration at the next levels. To specifically study tuning for temporal interval in the correlation step, we performed an experiment in which prefiltering and postintegration were held constant and in which we used a motion stimulus containing coherent motion for a single interval value only. The stimulus consisted of a sparse random dot pattern in which each dot was presented in two frames only, separated by a specified interval. On each frame, half of the dots were refreshed and the other half was a displaced reincarnation of the pattern generated one or several frames earlier. Motion energy statistics in such a stimulus do not vary from frame to frame, and the directional bias in spatiotemporal correlations is similar for different interval settings. We measured coherence thresholds for left-right direction discrimination by varying motion coherence levels in a Quest staircase procedure, as a function of both step size and interval. Results show that highest sensitivity was found for an interval of 17-42 ms, irrespective of viewing distance. The falloff at longer intervals was much sharper than previously described. Tuning for temporal interval was largely, but not completely, independent of step size. The optimal temporal interval slightly decreased with increasing step size. Similarly, the optimal step size decreased with increasing temporal interval.

  3. SOCIAL INTEGRATION: TESTING ANTECEDENTS OF TIME SPENT ONLINE

    Directory of Open Access Journals (Sweden)

    Lily Suriani Mohd Arif

    2013-07-01

    Full Text Available The literature on the relationship of social integration and time spent onlineprovides conflicting evidence of the relationship of social integration with timespent online. The study identifies and highlightsthe controversy and attempts toclarify the relationship of social integration withtime spent online bydecomposing the construct social integration into its affective and behavioraldimensions . Thestudy tests antecedents and effects of time spent online in arandom sample of senior level undergraduate students at a public university inMalaysia. The findings indicated that while self-report measures of behavioralsocial integration did not predict time spent online, and, the affective socialintegration had an inverse relationship with time spent online.

  4. Two-sorted Point-Interval Temporal Logics

    DEFF Research Database (Denmark)

    Balbiani, Philippe; Goranko, Valentin; Sciavicco, Guido

    2011-01-01

    There are two natural and well-studied approaches to temporal ontology and reasoning: point-based and interval-based. Usually, interval-based temporal reasoning deals with points as particular, duration-less intervals. Here we develop explicitly two-sorted point-interval temporal logical framework...... whereby time instants (points) and time periods (intervals) are considered on a par, and the perspective can shift between them within the formal discourse. We focus on fragments involving only modal operators that correspond to the inter-sort relations between points and intervals. We analyze...

  5. Comparative evaluation of nickel discharge from brackets in artificial saliva at different time intervals.

    Science.gov (United States)

    Jithesh, C; Venkataramana, V; Penumatsa, Narendravarma; Reddy, S N; Poornima, K Y; Rajasigamani, K

    2015-08-01

    To determine and compare the potential difference of nickel release from three different orthodontic brackets, in different artificial pH, in different time intervals. Twenty-seven samples of three different orthodontic brackets were selected and grouped as 1, 2, and 3. Each group was divided into three subgroups depending on the type of orthodontic brackets, salivary pH and the time interval. The Nickel release from each subgroup were analyzed by using inductively coupled plasma-Atomic Emission Spectrophotometer (Perkin Elmer, Optima 2100 DV, USA) model. Quantitative analysis of nickel was performed three times, and the mean value was used as result. ANOVA (F-test) was used to test the significant difference among the groups at 0.05 level of significance (P brackets have the highest at all 4.2 pH except in 120 h. The study result shows that the nickel release from the recycled stainless steel brackets is highest. Metal slot ceramic bracket release significantly less nickel. So, recycled stainless steel brackets should not be used for nickel allergic patients. Metal slot ceramic brackets are advisable.

  6. A network of spiking neurons that can represent interval timing: mean field analysis.

    Science.gov (United States)

    Gavornik, Jeffrey P; Shouval, Harel Z

    2011-04-01

    Despite the vital importance of our ability to accurately process and encode temporal information, the underlying neural mechanisms are largely unknown. We have previously described a theoretical framework that explains how temporal representations, similar to those reported in the visual cortex, can form in locally recurrent cortical networks as a function of reward modulated synaptic plasticity. This framework allows networks of both linear and spiking neurons to learn the temporal interval between a stimulus and paired reward signal presented during training. Here we use a mean field approach to analyze the dynamics of non-linear stochastic spiking neurons in a network trained to encode specific time intervals. This analysis explains how recurrent excitatory feedback allows a network structure to encode temporal representations.

  7. Contrasting Perspectives of Anesthesiologists and Gastroenterologists on the Optimal Time Interval between Bowel Preparation and Endoscopic Sedation

    Directory of Open Access Journals (Sweden)

    Deepak Agrawal

    2015-01-01

    Full Text Available Background. The optimal time interval between the last ingestion of bowel prep and sedation for colonoscopy remains controversial, despite guidelines that sedation can be administered 2 hours after consumption of clear liquids. Objective. To determine current practice patterns among anesthesiologists and gastroenterologists regarding the optimal time interval for sedation after last ingestion of bowel prep and to understand the rationale underlying their beliefs. Design. Questionnaire survey of anesthesiologists and gastroenterologists in the USA. The questions were focused on the preferred time interval of endoscopy after a polyethylene glycol based preparation in routine cases and select conditions. Results. Responses were received from 109 anesthesiologists and 112 gastroenterologists. 96% of anesthesiologists recommended waiting longer than 2 hours until sedation, in contrast to only 26% of gastroenterologists. The main reason for waiting >2 hours was that PEG was not considered a clear liquid. Most anesthesiologists, but not gastroenterologists, waited longer in patients with history of diabetes or reflux. Conclusions. Anesthesiologists and gastroenterologists do not agree on the optimal interval for sedation after last drink of bowel prep. Most anesthesiologists prefer to wait longer than the recommended 2 hours for clear liquids. The data suggest a need for clearer guidelines on this issue.

  8. Two intervals Rényi entanglement entropy of compact free boson on torus

    International Nuclear Information System (INIS)

    Liu, Feihu; Liu, Xiao

    2016-01-01

    We compute the N=2 Rényi entanglement entropy of two intervals at equal time in a circle, for the theory of a 2D compact complex free scalar at finite temperature. This is carried out by performing functional integral on a genus 3 ramified cover of the torus, wherein the quantum part of the integral is captured by the four point function of twist fields on the worldsheet torus, and the classical piece is given by summing over winding modes of the genus 3 surface onto the target space torus. The final result is given in terms of a product of theta functions and certain multi-dimensional theta functions. We demonstrate the T-duality invariance of the result. We also study its low temperature limit. In the case in which the size of the intervals and of their separation are much smaller than the whole system, our result is in exact agreement with the known result for two intervals on an infinite system at zero temperature http://dx.doi.org/10.1088/1742-5468/2009/11/P11001. In the case in which the separation between the two intervals is much smaller than the interval length, the leading thermal corrections take the same universal form as proposed in http://dx.doi.org/10.1103/PhysRevLett.112.171603, http://dx.doi.org/10.1103/PhysRevD.91.105013 for Rényi entanglement entropy of a single interval.

  9. Prognostic value of cardiac time intervals measured by tissue Doppler imaging M-mode in the general population

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Mogelvang, Rasmus; Jensen, Jan Skov

    2015-01-01

    : In a large prospective community-based study, cardiac function was evaluated in 1915 participants by both conventional echocardiography and TDI. The cardiac time intervals, including the isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT) and ejection time (ET), were obtained by TDI M...

  10. The delayed reproduction of long time intervals defined by innocuous thermal sensation.

    Science.gov (United States)

    Khoshnejad, Mina; Martinu, Kristina; Grondin, Simon; Rainville, Pierre

    2016-04-01

    The presence of discrete events during an interval to be estimated generally causes a dilation of perceived duration (event-filling effect). Here, we investigated this phenomenon in the thermal modality using multi-seconds (19 s) innocuous cool stimuli that were either constant (continuous interval) or fluctuating to create three discrete sensory events (segmented interval). Moreover, we introduced a delay following stimulus offset, before the reproduction phase, to allow for a direct comparison with our recent study showing an underestimation of duration in a delayed reproduction task of heat pain sensations (Khoshnejad et al. in Pain 155:581-590, 2014. doi: 10.1016/j.pain.2013.12.015 ). The event-filling effect was tested by comparing the delayed reproduction of the segmented and the continuous stimuli in experimental conditions asking participants to (1) reproduce the dynamics of the sensation (i.e., changes in sensory intensity over time) or (2) reproduce only the interval duration (i.e., sensation onset-to-offset). A perceptual (control) condition required participants to report changes in sensation concurrently with the stimulus. Results of the dynamic task confirmed the underestimation of duration in the delayed reproduction task, but this effect was only found with the continuous and not with the segmented stimulus. This implies that the dilation of duration produced by segmentation might compensate for the underestimation of duration in this delayed reproduction task. However, this temporal dilation effect was only observed when participants were required to attend and reproduce the dynamics of sensation. These results suggest that the event-filling effect can be observed in the thermal sensory modality and that attention directed toward changes in sensory intensity might contribute to this effect.

  11. Blip decomposition of the path integral: exponential acceleration of real-time calculations on quantum dissipative systems.

    Science.gov (United States)

    Makri, Nancy

    2014-10-07

    The real-time path integral representation of the reduced density matrix for a discrete system in contact with a dissipative medium is rewritten in terms of the number of blips, i.e., elementary time intervals over which the forward and backward paths are not identical. For a given set of blips, it is shown that the path sum with respect to the coordinates of all remaining time points is isomorphic to that for the wavefunction of a system subject to an external driving term and thus can be summed by an inexpensive iterative procedure. This exact decomposition reduces the number of terms by a factor that increases exponentially with propagation time. Further, under conditions (moderately high temperature and/or dissipation strength) that lead primarily to incoherent dynamics, the "fully incoherent limit" zero-blip term of the series provides a reasonable approximation to the dynamics, and the blip series converges rapidly to the exact result. Retention of only the blips required for satisfactory convergence leads to speedup of full-memory path integral calculations by many orders of magnitude.

  12. Determining diabetic retinopathy screening interval based on time from no retinopathy to laser therapy.

    Science.gov (United States)

    Hughes, Daniel; Nair, Sunil; Harvey, John N

    2017-12-01

    Objectives To determine the necessary screening interval for retinopathy in diabetic patients with no retinopathy based on time to laser therapy and to assess long-term visual outcome following screening. Methods In a population-based community screening programme in North Wales, 2917 patients were followed until death or for approximately 12 years. At screening, 2493 had no retinopathy; 424 had mostly minor degrees of non-proliferative retinopathy. Data on timing of first laser therapy and visual outcome following screening were obtained from local hospitals and ophthalmology units. Results Survival analysis showed that very few of the no retinopathy at screening group required laser therapy in the early years compared with the non-proliferative retinopathy group ( p retinopathy at screening group required laser therapy, and at three years 0.2% (cumulative), lower rates of treatment than have been suggested by analyses of sight-threatening retinopathy determined photographically. At follow-up (mean 7.8 ± 4.6 years), mild to moderate visual impairment in one or both eyes due to diabetic retinopathy was more common in those with retinopathy at screening (26% vs. 5%, p diabetes occurred in only 1 in 1000. Conclusions Optimum screening intervals should be determined from time to active treatment. Based on requirement for laser therapy, the screening interval for diabetic patients with no retinopathy can be extended to two to three years. Patients who attend for retinal screening and treatment who have no or non-proliferative retinopathy now have a very low risk of eventual blindness from diabetes.

  13. Symplectic integrators with adaptive time steps

    Science.gov (United States)

    Richardson, A. S.; Finn, J. M.

    2012-01-01

    In recent decades, there have been many attempts to construct symplectic integrators with variable time steps, with rather disappointing results. In this paper, we identify the causes for this lack of performance, and find that they fall into two categories. In the first, the time step is considered a function of time alone, Δ = Δ(t). In this case, backward error analysis shows that while the algorithms remain symplectic, parametric instabilities may arise because of resonance between oscillations of Δ(t) and the orbital motion. In the second category the time step is a function of phase space variables Δ = Δ(q, p). In this case, the system of equations to be solved is analyzed by introducing a new time variable τ with dt = Δ(q, p) dτ. The transformed equations are no longer in Hamiltonian form, and thus do not benefit from integration methods which would be symplectic for Hamiltonian systems. We analyze two methods for integrating the transformed equations which do, however, preserve the structure of the original equations. The first is an extended phase space method, which has been successfully used in previous studies of adaptive time step symplectic integrators. The second, novel, method is based on a non-canonical mixed-variable generating function. Numerical trials for both of these methods show good results, without parametric instabilities or spurious growth or damping. It is then shown how to adapt the time step to an error estimate found by backward error analysis, in order to optimize the time-stepping scheme. Numerical results are obtained using this formulation and compared with other time-stepping schemes for the extended phase space symplectic method.

  14. Hospital process intervals, not EMS time intervals, are the most important predictors of rapid reperfusion in EMS Patients with ST-segment elevation myocardial infarction.

    Science.gov (United States)

    Clark, Carol Lynn; Berman, Aaron D; McHugh, Ann; Roe, Edward Jedd; Boura, Judith; Swor, Robert A

    2012-01-01

    To assess the relationship of emergency medical services (EMS) intervals and internal hospital intervals to the rapid reperfusion of patients with ST-segment elevation myocardial infarction (STEMI). We performed a secondary analysis of a prospectively collected database of STEMI patients transported to a large academic community hospital between January 1, 2004, and December 31, 2009. EMS and hospital data intervals included EMS scene time, transport time, hospital arrival to myocardial infarction (MI) team activation (D2Page), page to catheterization laboratory arrival (P2Lab), and catheterization laboratory arrival to reperfusion (L2B). We used two outcomes: EMS scene arrival to reperfusion (S2B) ≤90 minutes and hospital arrival to reperfusion (D2B) ≤90 minutes. Means and proportions are reported. Pearson chi-square and multivariate regression were used for analysis. During the study period, we included 313 EMS-transported STEMI patients with 298 (95.2%) MI team activations. Of these STEMI patients, 295 (94.2%) were taken to the cardiac catheterization laboratory and 244 (78.0%) underwent percutaneous coronary intervention (PCI). For the patients who underwent PCI, 127 (52.5%) had prehospital EMS activation, 202 (82.8%) had D2B ≤90 minutes, and 72 (39%) had S2B ≤90 minutes. In a multivariate analysis, hospital processes EMS activation (OR 7.1, 95% CI 2.7, 18.4], Page to Lab [6.7, 95% CI 2.3, 19.2] and Lab arrival to Reperfusion [18.5, 95% CI 6.1, 55.6]) were the most important predictors of Scene to Balloon ≤ 90 minutes. EMS scene and transport intervals also had a modest association with rapid reperfusion (OR 0.85, 95% CI 0.78, 0.93 and OR 0.89, 95% CI 0.83, 0.95, respectively). In a secondary analysis, Hospital processes (Door to Page [OR 44.8, 95% CI 8.6, 234.4], Page 2 Lab [OR 5.4, 95% CI 1.9, 15.3], and Lab arrival to Reperfusion [OR 14.6 95% CI 2.5, 84.3]), but not EMS scene and transport intervals were the most important predictors D2B ≤90

  15. Is the time interval between surgery and radiotherapy important in operable nonsmall cell lung cancer? A retrospective analysis of 340 cases

    International Nuclear Information System (INIS)

    Wuerschmidt, Florian; Buenemann, Henry; Ehnert, Michael; Heilmann, Hans-Peter

    1997-01-01

    Purpose: To evaluate the influence of prognostic factors in postoperative radiotherapy of NSCLC with special emphasis on the time interval between surgery and start of radiotherapy. Methods and Materials: Between January 1976 and December 1993, 340 cases were treated and retrospectively analyzed meeting the following criteria: complete follow-up; complete staging information including pathological confirmation of resection status; maximum interval between surgery (SX) and radiotherapy (RT) of 12 weeks (median 36 days, range 18 to 84 days); minimum dose of 50 Gy (R0), and maximum dose of 70 Gy (R2). Two hundred thirty patients (68%) had N2 disease; 228 patients were completely resected (R0). One hundred six (31%) had adenocarcinoma, 172 (51%) squamous cell carcinoma. Results: In univariate analysis, Karnofsky performance status (90+ > 60-80%; p = 0.019 log rank), resection status stratified for nodal disease (R+ < R0; p = 0.046), and the time interval between SX and RT were of significant importance. Patients with a long interval (37 to 84 days) had higher 5-year survival rates (26%) and a median survival time (MST: 21.9 months, 95% C.I. 17.2 to 28.6 months) than patients with a short interval (18 to 36 days: 15%; 14.9 months, 13 to 19.9 months; p = 0.013). A further subgroup analysis revealed significant higher survival rates in patients with a long interval in N0/1 disease (p = 0.011) and incompletely resected NSCLC (p = 0.012). In multivariate analysis, the time interval had a p-value of 0.009 (nodal disease: p = 0.0083; KPI: p = 0.0037; sex: p = 0.035). Conclusion: Shortening the time interval between surgery and postoperative radiotherapy to less than 6 weeks even in R+ cases is not necessary. Survival of patients with a long interval between surgery and start of radiotherapy was better in this retrospective analysis as compared to patients with a short interval

  16. Perceptual inequality between two neighboring time intervals defined by sound markers: correspondence between neurophysiological and psychological data

    Directory of Open Access Journals (Sweden)

    Takako eMitsudo

    2014-09-01

    Full Text Available Brain activity related to time estimation processes in humans was analyzed using a perceptual phenomenon called auditory temporal assimilation. In a typical stimulus condition, two neighboring time intervals (T1 and T2 in this order are perceived as equal even when the physical lengths of these time intervals are considerably different. Our previous event-related potential (ERP study demonstrated that a slow negative component (SNCt appears in the right-frontal brain area (around the F8 electrode after T2, which is associated with judgment of the equality/inequality of T1 and T2. In the present study, we conducted two ERP experiments to further confirm the robustness of the SNCt. The stimulus patterns consisted of two neighboring time intervals marked by three successive tone bursts. Thirteen participants only listened to the patterns in the first session, and judged the equality/inequality of T1 and T2 in the next session. Behavioral data showed typical temporal assimilation. The ERP data revealed that three components (N1; contingent negative variation, CNV; and SNCt emerged related to the temporal judgment. The N1 appeared in the central area, and its peak latencies corresponded to the physical timing of each marker onset. The CNV component appeared in the frontal area during T2 presentation, and its amplitude increased as a function of T1. The SNCt appeared in the right-frontal area after the presentation of T1 and T2, and its magnitude was larger for the temporal patterns causing perceptual inequality. The SNCt was also correlated with the perceptual equality/inequality of the same stimulus pattern, and continued up to about 400 ms after the end of T2. These results suggest that the SNCt can be a signature of equality/inequality judgment, which derives from the comparison of the two neighboring time intervals.

  17. Diagnostic Efficiency of MR Imaging of the Knee. Relationship to time Interval between MR and Arthroscopy

    International Nuclear Information System (INIS)

    Barrera, M. C.; Recondo, J. A.; Aperribay, M.; Gervas, C.; Fernandez, E.; Alustiza, J. M.

    2003-01-01

    To evaluate the efficiency of magnetic resonance (MR) in the diagnosis of knee lesions and how the results are influenced by the time interval between MR and arthroscopy. 248 knees studied by MR were retrospectively analyzed, as well as those which also underwent arthroscopy. Arthroscopy was considered to be the gold standard, MR diagnostic capacity was evaluated for both meniscal and cruciate ligament lesions. Sensitivity, specificity and Kappa index were calculated for the set of all knees included in the study (248), for those in which the time between MR and arthroscopy was less than or equal to three months (134) and for those in which the time between both procedures was less than or equal to one month. Sensitivity, specificity and Kappa index of the MR had global values of 96.5%, 70% and 71%, respectively. When the interval between MR and arthroscopy was less than or equal to three months, sensitivity, specificity and Kappa index were 95.5%, 75% and 72%, respectively. When it was less than or equal to one month, sensitivity was 100%, specificity was 87.5% and Kappa index was 91%. MR is an excellent tool for the diagnosis of knee lesions. Higher MR values of sensitivity, specificity and Kappa index are obtained when the time interval between both procedures is kept to a minimum. (Author) 11 refs

  18. Most probable dimension value and most flat interval methods for automatic estimation of dimension from time series

    International Nuclear Information System (INIS)

    Corana, A.; Bortolan, G.; Casaleggio, A.

    2004-01-01

    We present and compare two automatic methods for dimension estimation from time series. Both methods, based on conceptually different approaches, work on the derivative of the bi-logarithmic plot of the correlation integral versus the correlation length (log-log plot). The first method searches for the most probable dimension values (MPDV) and associates to each of them a possible scaling region. The second one searches for the most flat intervals (MFI) in the derivative of the log-log plot. The automatic procedures include the evaluation of the candidate scaling regions using two reliability indices. The data set used to test the methods consists of time series from known model attractors with and without the addition of noise, structured time series, and electrocardiographic signals from the MIT-BIH ECG database. Statistical analysis of results was carried out by means of paired t-test, and no statistically significant differences were found in the large majority of the trials. Consistent results are also obtained dealing with 'difficult' time series. In general for a more robust and reliable estimate, the use of both methods may represent a good solution when time series from complex systems are analyzed. Although we present results for the correlation dimension only, the procedures can also be used for the automatic estimation of generalized q-order dimensions and pointwise dimension. We think that the proposed methods, eliminating the need of operator intervention, allow a faster and more objective analysis, thus improving the usefulness of dimension analysis for the characterization of time series obtained from complex dynamical systems

  19. Correct Bayesian and frequentist intervals are similar

    International Nuclear Information System (INIS)

    Atwood, C.L.

    1986-01-01

    This paper argues that Bayesians and frequentists will normally reach numerically similar conclusions, when dealing with vague data or sparse data. It is shown that both statistical methodologies can deal reasonably with vague data. With sparse data, in many important practical cases Bayesian interval estimates and frequentist confidence intervals are approximately equal, although with discrete data the frequentist intervals are somewhat longer. This is not to say that the two methodologies are equally easy to use: The construction of a frequentist confidence interval may require new theoretical development. Bayesians methods typically require numerical integration, perhaps over many variables. Also, Bayesian can easily fall into the trap of over-optimism about their amount of prior knowledge. But in cases where both intervals are found correctly, the two intervals are usually not very different. (orig.)

  20. Chaotic dynamics from interspike intervals

    DEFF Research Database (Denmark)

    Pavlov, A N; Sosnovtseva, Olga; Mosekilde, Erik

    2001-01-01

    Considering two different mathematical models describing chaotic spiking phenomena, namely, an integrate-and-fire and a threshold-crossing model, we discuss the problem of extracting dynamics from interspike intervals (ISIs) and show that the possibilities of computing the largest Lyapunov expone...

  1. Time-dependent integral transport equation kernels, leakage rates and collision rates for plane and spherical geometry

    International Nuclear Information System (INIS)

    Henderson, D.L.

    1987-01-01

    Time-dependent integral transport equation flux and current kernels for plane and spherical geometry are derived for homogeneous media. Using the multiple collision formalism, isotropic sources that are delta distributions in time are considered for four different problems. The plane geometry flux kernel is applied to a uniformly distributed source within an infinite medium and to a surface source in a semi-infinite medium. The spherical flux kernel is applied to a point source in an infinite medium and to a point source at the origin of a finite sphere. The time-dependent first-flight leakage rates corresponding to the existing steady state first-flight escape probabilities are computed by the Laplace transform technique assuming a delta distribution source in time. The case of a constant source emitting neutrons over a time interval, Δt, for a spatially uniform source is obtained for a slab and a sphere. Time-dependent first-flight leakage rates are also determined for the general two region spherical medium problem for isotropic sources with a delta distribution in time uniformly distributed throughout both the inner and outer regions. The time-dependent collision rates due to the uncollided neutrons are computed for a slab and a sphere using the time-dependent first-flight leakage rates and the time-dependent continuity equation. The case of a constant source emitting neutrons over a time interval, Δt, is also considered

  2. Time Interval to Initiation of Contraceptive Methods Following ...

    African Journals Online (AJOL)

    2018-01-30

    Jan 30, 2018 ... interval between a woman's last childbirth and the initiation of contraception. Materials and ..... DF=Degree of freedom; χ2=Chi‑square test ..... practice of modern contraception among single women in a rural and urban ...

  3. Designing driver assistance systems with crossmodal signals: multisensory integration rules for saccadic reaction times apply.

    Directory of Open Access Journals (Sweden)

    Rike Steenken

    Full Text Available Modern driver assistance systems make increasing use of auditory and tactile signals in order to reduce the driver's visual information load. This entails potential crossmodal interaction effects that need to be taken into account in designing an optimal system. Here we show that saccadic reaction times to visual targets (cockpit or outside mirror, presented in a driving simulator environment and accompanied by auditory or tactile accessories, follow some well-known spatiotemporal rules of multisensory integration, usually found under confined laboratory conditions. Auditory nontargets speed up reaction time by about 80 ms. The effect tends to be maximal when the nontarget is presented 50 ms before the target and when target and nontarget are spatially coincident. The effect of a tactile nontarget (vibrating steering wheel was less pronounced and not spatially specific. It is shown that the average reaction times are well-described by the stochastic "time window of integration" model for multisensory integration developed by the authors. This two-stage model postulates that crossmodal interaction occurs only if the peripheral processes from the different sensory modalities terminate within a fixed temporal interval, and that the amount of crossmodal interaction manifests itself in an increase or decrease of second stage processing time. A qualitative test is consistent with the model prediction that the probability of interaction, but not the amount of crossmodal interaction, depends on target-nontarget onset asynchrony. A quantitative model fit yields estimates of individual participants' parameters, including the size of the time window. Some consequences for the design of driver assistance systems are discussed.

  4. An experimental evaluation of electrical skin conductivity changes in postmortem interval and its assessment for time of death estimation.

    Science.gov (United States)

    Cantürk, İsmail; Karabiber, Fethullah; Çelik, Safa; Şahin, M Feyzi; Yağmur, Fatih; Kara, Sadık

    2016-02-01

    In forensic medicine, estimation of the time of death (ToD) is one of the most important and challenging medico-legal problems. Despite the partial accomplishments in ToD estimations to date, the error margin of ToD estimation is still too large. In this study, electrical conductivity changes were experimentally investigated in the postmortem interval in human cases. Electrical conductivity measurements give some promising clues about the postmortem interval. A living human has a natural electrical conductivity; in the postmortem interval, intracellular fluids gradually leak out of cells. These leaked fluids combine with extra-cellular fluids in tissues and since both fluids are electrolytic, intracellular fluids help increase conductivity. Thus, the level of electrical conductivity is expected to increase with increased time after death. In this study, electrical conductivity tests were applied for six hours. The electrical conductivity of the cases exponentially increased during the tested time period, indicating a positive relationship between electrical conductivity and the postmortem interval. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Practical Implementation for the interval type-2 fuzzy PID controller using a low cost microcontroller

    Directory of Open Access Journals (Sweden)

    Ahmad M. El-Nagar

    2014-06-01

    Full Text Available In this study, we propose an embedded real-time interval type-2 fuzzy proportional – integral – derivative (IT2F-PID controller which is a parallel combination of the interval type-2 fuzzy proportional – integral (IT2F-PI controller and the interval type-2 fuzzy proportional – derivative (IT2F-PD controller. The proposed IT2F-PID controller is able to handle the effect of the system uncertainties due to the structure of the interval type-2 fuzzy logic controller. The proposed IT2F-PID controller is implemented practically using a low cost PIC microcontroller for controlling the uncertain nonlinear inverted pendulum to minimize the effect of the system uncertainties due to the uncertainty in the mass of the pendulum, the measurement error in the rotation angle of the pendulum and the structural uncertainty. The test is carried out using the hardware-in-the-loop (HIL simulation. The experimental results show that the performance of the IT2F-PID controller improves significantly the performance over a wide range of system uncertainties.

  6. Quantifying Effusion Rates at Active Volcanoes through Integrated Time-Lapse Laser Scanning and Photography

    Directory of Open Access Journals (Sweden)

    Neil Slatcher

    2015-11-01

    Full Text Available During volcanic eruptions, measurements of the rate at which magma is erupted underpin hazard assessments. For eruptions dominated by the effusion of lava, estimates are often made using satellite data; here, in a case study at Mount Etna (Sicily, we make the first measurements based on terrestrial laser scanning (TLS, and we also include explosive products. During the study period (17–21 July 2012, regular Strombolian explosions were occurring within the Bocca Nuova crater, producing a ~50 m-high scoria cone and a small lava flow field. TLS surveys over multi-day intervals determined a mean cone growth rate (effusive and explosive products of ~0.24 m3·s−1. Differences between 0.3-m resolution DEMs acquired at 10-minute intervals captured the evolution of a breakout lava flow lobe advancing at 0.01–0.03 m3·s−1. Partial occlusion within the crater prevented similar measurement of the main flow, but integrating TLS data with time-lapse imagery enabled lava viscosity (7.4 × 105 Pa·s to be derived from surface velocities and, hence, a flux of 0.11 m3·s−1 to be calculated. Total dense rock equivalent magma discharge estimates are ~0.1–0.2 m3·s−1 over the measurement period and suggest that simultaneous estimates from satellite data are somewhat overestimated. Our results support the use of integrated TLS and time-lapse photography for ground-truthing space-based measurements and highlight the value of interactive image analysis when automated approaches, such as particle image velocimetry (PIV, fail.

  7. Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness?

    Science.gov (United States)

    Gillen, Jenna B; Gibala, Martin J

    2014-03-01

    Growing research suggests that high-intensity interval training (HIIT) is a time-efficient exercise strategy to improve cardiorespiratory and metabolic health. "All out" HIIT models such as Wingate-type exercise are particularly effective, but this type of training may not be safe, tolerable or practical for many individuals. Recent studies, however, have revealed the potential for other models of HIIT, which may be more feasible but are still time-efficient, to stimulate adaptations similar to more demanding low-volume HIIT models and high-volume endurance-type training. As little as 3 HIIT sessions per week, involving ≤10 min of intense exercise within a time commitment of ≤30 min per session, including warm-up, recovery between intervals and cool down, has been shown to improve aerobic capacity, skeletal muscle oxidative capacity, exercise tolerance and markers of disease risk after only a few weeks in both healthy individuals and people with cardiometabolic disorders. Additional research is warranted, as studies conducted have been relatively short-term, with a limited number of measurements performed on small groups of subjects. However, given that "lack of time" remains one of the most commonly cited barriers to regular exercise participation, low-volume HIIT is a time-efficient exercise strategy that warrants consideration by health practitioners and fitness professionals.

  8. Simple estimation procedures for regression analysis of interval-censored failure time data under the proportional hazards model.

    Science.gov (United States)

    Sun, Jianguo; Feng, Yanqin; Zhao, Hui

    2015-01-01

    Interval-censored failure time data occur in many fields including epidemiological and medical studies as well as financial and sociological studies, and many authors have investigated their analysis (Sun, The statistical analysis of interval-censored failure time data, 2006; Zhang, Stat Modeling 9:321-343, 2009). In particular, a number of procedures have been developed for regression analysis of interval-censored data arising from the proportional hazards model (Finkelstein, Biometrics 42:845-854, 1986; Huang, Ann Stat 24:540-568, 1996; Pan, Biometrics 56:199-203, 2000). For most of these procedures, however, one drawback is that they involve estimation of both regression parameters and baseline cumulative hazard function. In this paper, we propose two simple estimation approaches that do not need estimation of the baseline cumulative hazard function. The asymptotic properties of the resulting estimates are given, and an extensive simulation study is conducted and indicates that they work well for practical situations.

  9. An Efficient Format for Nearly Constant-Time Access to Arbitrary Time Intervals in Large Trace Files

    Directory of Open Access Journals (Sweden)

    Anthony Chan

    2008-01-01

    Full Text Available A powerful method to aid in understanding the performance of parallel applications uses log or trace files containing time-stamped events and states (pairs of events. These trace files can be very large, often hundreds or even thousands of megabytes. Because of the cost of accessing and displaying such files, other methods are often used that reduce the size of the tracefiles at the cost of sacrificing detail or other information. This paper describes a hierarchical trace file format that provides for display of an arbitrary time window in a time independent of the total size of the file and roughly proportional to the number of events within the time window. This format eliminates the need to sacrifice data to achieve a smaller trace file size (since storage is inexpensive, it is necessary only to make efficient use of bandwidth to that storage. The format can be used to organize a trace file or to create a separate file of annotations that may be used with conventional trace files. We present an analysis of the time to access all of the events relevant to an interval of time and we describe experiments demonstrating the performance of this file format.

  10. Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance.

    Science.gov (United States)

    Molero-Chamizo, Andrés; Alameda Bailén, José R; Garrido Béjar, Tamara; García López, Macarena; Jaén Rodríguez, Inmaculada; Gutiérrez Lérida, Carolina; Pérez Panal, Silvia; González Ángel, Gloria; Lemus Corchero, Laura; Ruiz Vega, María J; Nitsche, Michael A; Rivera-Urbina, Guadalupe N

    2018-02-01

    Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS-namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.

  11. A higher order space-time Galerkin scheme for time domain integral equations

    KAUST Repository

    Pray, Andrew J.

    2014-12-01

    Stability of time domain integral equation (TDIE) solvers has remained an elusive goal formany years. Advancement of this research has largely progressed on four fronts: 1) Exact integration, 2) Lubich quadrature, 3) smooth temporal basis functions, and 4) space-time separation of convolutions with the retarded potential. The latter method\\'s efficacy in stabilizing solutions to the time domain electric field integral equation (TD-EFIE) was previously reported for first-order surface descriptions (flat elements) and zeroth-order functions as the temporal basis. In this work, we develop the methodology necessary to extend the scheme to higher order surface descriptions as well as to enable its use with higher order basis functions in both space and time. These basis functions are then used in a space-time Galerkin framework. A number of results are presented that demonstrate convergence in time. The viability of the space-time separation method in producing stable results is demonstrated experimentally for these examples.

  12. A higher order space-time Galerkin scheme for time domain integral equations

    KAUST Repository

    Pray, Andrew J.; Beghein, Yves; Nair, Naveen V.; Cools, Kristof; Bagci, Hakan; Shanker, Balasubramaniam

    2014-01-01

    Stability of time domain integral equation (TDIE) solvers has remained an elusive goal formany years. Advancement of this research has largely progressed on four fronts: 1) Exact integration, 2) Lubich quadrature, 3) smooth temporal basis functions, and 4) space-time separation of convolutions with the retarded potential. The latter method's efficacy in stabilizing solutions to the time domain electric field integral equation (TD-EFIE) was previously reported for first-order surface descriptions (flat elements) and zeroth-order functions as the temporal basis. In this work, we develop the methodology necessary to extend the scheme to higher order surface descriptions as well as to enable its use with higher order basis functions in both space and time. These basis functions are then used in a space-time Galerkin framework. A number of results are presented that demonstrate convergence in time. The viability of the space-time separation method in producing stable results is demonstrated experimentally for these examples.

  13. Improving Delay-Range-Dependent Stability Condition for Systems with Interval Time-Varying Delay

    Directory of Open Access Journals (Sweden)

    Wei Qian

    2013-01-01

    Full Text Available This paper discusses the delay-range-dependent stability for systems with interval time-varying delay. Through defining the new Lyapunov-Krasovskii functional and estimating the derivative of the LKF by introducing new vectors, using free matrices and reciprocally convex approach, the new delay-range-dependent stability conditions are obtained. Two well-known examples are given to illustrate the less conservatism of the proposed theoretical results.

  14. TL glow ratios at different temperature intervals of integration in thermoluminescence method. Comparison of Japanese standard (MHLW notified) method with CEN standard methods

    International Nuclear Information System (INIS)

    Todoriki, Setsuko; Saito, Kimie; Tsujimoto, Yuka

    2008-01-01

    The effect of the integration temperature intervals of TL intensities on the TL glow ratio was examined in comparison of the notified method of the Ministry of Health, Labour and Welfare (MHLW method) with EN1788. Two kinds of un-irradiated geological standard rock and three kinds of spices (black pepper, turmeric, and oregano) irradiated at 0.3 kGy or 1.0 kGy were subjected to TL analysis. Although the TL glow ratio exceeded 0.1 in the andesite according to the calculation of the MHLW notified method (integration interval; 70-490degC), the maximum of the first glow were observed at 300degC or more, attributed the influence of the natural radioactivity and distinguished from food irradiation. When the integration interval was set to 166-227degC according to EN1788, the TL glow ratios became remarkably smaller than 0.1, and the evaluation of the un-irradiated sample became more clear. For spices, the TL glow ratios by the MHLW notified method fell below 0.1 in un-irradiated samples and exceeded 0.1 in irradiated ones. Moreover, Glow1 maximum temperatures of the irradiated samples were observed at the range of 168-196degC, and those of un-irradiated samples were 258degC or more. Therefore, all samples were correctly judged by the criteria of the MHLW method. However, based on the temperature range of integration defined by EN1788, the TL glow ratio of un-irradiated samples remarkably became small compared with that of the MHLW method, and the discrimination of the irradiated sample from non-irradiation sample became clearer. (author)

  15. Association between prehospital time interval and short-term outcome in acute heart failure patients.

    Science.gov (United States)

    Takahashi, Masashi; Kohsaka, Shun; Miyata, Hiroaki; Yoshikawa, Tsutomu; Takagi, Atsutoshi; Harada, Kazumasa; Miyamoto, Takamichi; Sakai, Tetsuo; Nagao, Ken; Sato, Naoki; Takayama, Morimasa

    2011-09-01

    Acute heart failure (AHF) is one of the most frequently encountered cardiovascular conditions that can seriously affect the patient's prognosis. However, the importance of early triage and treatment initiation in the setting of AHF has not been recognized. The Tokyo Cardiac Care Unit Network Database prospectively collected information of emergency admissions to acute cardiac care facilities in 2005-2007 from 67 participating hospitals in the Tokyo metropolitan area. We analyzed records of 1,218 AHF patients transported to medical centers via emergency medical services (EMS). AHF was defined as rapid onset or change in the signs and symptoms of heart failure, resulting in the need for urgent therapy. Patients with acute coronary syndrome were excluded from this analysis. Logistic regression analysis was performed to calculate the risk-adjusted in-hospital mortality. A majority of the patients were elderly (76.1 ± 11.5 years old) and male (54.1%). The overall in-hospital mortality rate was 6.0%. The median time interval between symptom onset and EMS arrival (response time) was 64 minutes (interquartile range [IQR] 26-205 minutes), and that between EMS arrival and ER arrival (transportation time) was 27 minutes (IQR 9-78 minutes). The risk-adjusted mortality increased with transportation time, but did not correlate with the response time. Those who took >45 minutes to arrive at the medical centers were at a higher risk for in-hospital mortality (odds ratio 2.24, 95% confidence interval 1.17-4.31; P = .015). Transportation time correlated with risk-adjusted mortality, and steps should be taken to reduce the EMS transfer time to improve the outcome in AHF patients. Copyright © 2011 Elsevier Inc. All rights reserved.

  16. Time Interval to Initiation of Contraceptive Methods Following ...

    African Journals Online (AJOL)

    Objectives: The objectives of the study were to determine factors affecting the interval between a woman's last childbirth and the initiation of contraception. Materials and Methods: This was a retrospective study. Family planning clinic records of the Barau Dikko Teaching Hospital Kaduna from January 2000 to March 2014 ...

  17. Model for the respiratory modulation of the heart beat-to-beat time interval series

    Science.gov (United States)

    Capurro, Alberto; Diambra, Luis; Malta, C. P.

    2005-09-01

    In this study we present a model for the respiratory modulation of the heart beat-to-beat interval series. The model consists of a set of differential equations used to simulate the membrane potential of a single rabbit sinoatrial node cell, excited with a periodic input signal with added correlated noise. This signal, which simulates the input from the autonomous nervous system to the sinoatrial node, was included in the pacemaker equations as a modulation of the iNaK current pump and the potassium current iK. We focus at modeling the heart beat-to-beat time interval series from normal subjects during meditation of the Kundalini Yoga and Chi techniques. The analysis of the experimental data indicates that while the embedding of pre-meditation and control cases have a roughly circular shape, it acquires a polygonal shape during meditation, triangular for the Kundalini Yoga data and quadrangular in the case of Chi data. The model was used to assess the waveshape of the respiratory signals needed to reproduce the trajectory of the experimental data in the phase space. The embedding of the Chi data could be reproduced using a periodic signal obtained by smoothing a square wave. In the case of Kundalini Yoga data, the embedding was reproduced with a periodic signal obtained by smoothing a triangular wave having a rising branch of longer duration than the decreasing branch. Our study provides an estimation of the respiratory signal using only the heart beat-to-beat time interval series.

  18. Time interval between infective endocarditis first symptoms and diagnosis: relationship to infective endocarditis characteristics, microorganisms and prognosis.

    Science.gov (United States)

    N'Guyen, Yohan; Duval, Xavier; Revest, Matthieu; Saada, Matthieu; Erpelding, Marie-Line; Selton-Suty, Christine; Bouchiat, Coralie; Delahaye, François; Chirouze, Catherine; Alla, François; Strady, Christophe; Hoen, Bruno

    2017-03-01

    To analyze the characteristics and outcome of infective endocarditis (IE) according to the time interval between IE first symptoms and diagnosis. Among the IE cases of a French population-based epidemiological survey, patients having early-diagnosed IE (diagnosis of IE within 1 month of first symptoms) were compared with those having late-diagnosed IE (diagnosis of IE more than 1 month after first symptoms). Among the 486 definite-IE, 124 (25%) had late-diagnosed IE whereas others had early-diagnosed IE. Early-diagnosed IE were independently associated with female gender (OR = 1.8; 95% CI [1.0-3.0]), prosthetic valve (OR= 2.6; 95% CI [1.4-5.0]) and staphylococci as causative pathogen (OR = 3.7; 95% CI [2.2-6.2]). Cardiac surgery theoretical indication rates were not different between early and late-diagnosed IE (56.3% vs 58.9%), whereas valve surgery performance was lower in early-diagnosed IE (41% vs 53%; p = .03). In-hospital mortality rates were higher in early-diagnosed IE than in late-diagnosed IE (25.1% vs 16.1%; p endocarditis, which time interval between first symptoms and diagnosis was less than one month, were mainly due to Staphylococcus aureus in France. Staphylococcus aureus infective endocarditis were associated with septic shock, transient ischemic attack or stroke and higher mortality rates than infective endocarditis due to other bacteria or infective endocarditis, which time interval between first symptoms and diagnosis was more than one month. Infective endocarditis, which time interval between first symptoms and diagnosis was more than one month, were accounting for one quarter of all infective endocarditis in our study and were associated with vertebral osteomyelitis and a higher rate of cardiac surgery performed for hemodynamic indication than other infective endocarditis.

  19. Wide-range time-to-digital converters with a high resolution

    International Nuclear Information System (INIS)

    Aul'chenko, V.M.

    1977-01-01

    A combined time-number converter in which measurements of time intervals to within a period of clock frequency are made directly and those within a period are by a time-amplitude-code conversion is described. It allows time intervals up to 4 mcsec with a resolution of 100 psec to be measured. The differential nonlinearity of conversion is not greater than +-1.5%, and the integral error from measurements of time intervals is not greater than +-100 psec

  20. Integrated survival analysis using an event-time approach in a Bayesian framework.

    Science.gov (United States)

    Walsh, Daniel P; Dreitz, Victoria J; Heisey, Dennis M

    2015-02-01

    Event-time or continuous-time statistical approaches have been applied throughout the biostatistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times. This has limited application of these analyses, particularly, within the ecological field where fates of marked animals may be unknown. To address these limitations, we developed an integrated approach within a Bayesian framework to estimate hazard rates in the face of unknown fates. We combine failure/survival times from individuals whose fates are known and times of which are interval-censored with information from those whose fates are unknown, and model the process of detecting animals with unknown fates. This provides the foundation for our integrated model and permits necessary parameter estimation. We provide the Bayesian model, its derivation, and use simulation techniques to investigate the properties and performance of our approach under several scenarios. Lastly, we apply our estimation technique using a piece-wise constant hazard function to investigate the effects of year, age, chick size and sex, sex of the tending adult, and nesting habitat on mortality hazard rates of the endangered mountain plover (Charadrius montanus) chicks. Traditional models were inappropriate for this analysis because fates of some individual chicks were unknown due to failed radio transmitters. Simulations revealed biases of posterior mean estimates were minimal (≤ 4.95%), and posterior distributions behaved as expected with RMSE of the estimates decreasing as sample sizes, detection probability, and survival increased. We determined mortality hazard rates for plover chicks were highest at birth weights and/or whose nest was within agricultural habitats. Based on its performance, our approach greatly expands the range of problems for which event-time analyses can be used by eliminating the need for having completely known fate data.

  1. Integrated survival analysis using an event-time approach in a Bayesian framework

    Science.gov (United States)

    Walsh, Daniel P.; Dreitz, VJ; Heisey, Dennis M.

    2015-01-01

    Event-time or continuous-time statistical approaches have been applied throughout the biostatistical literature and have led to numerous scientific advances. However, these techniques have traditionally relied on knowing failure times. This has limited application of these analyses, particularly, within the ecological field where fates of marked animals may be unknown. To address these limitations, we developed an integrated approach within a Bayesian framework to estimate hazard rates in the face of unknown fates. We combine failure/survival times from individuals whose fates are known and times of which are interval-censored with information from those whose fates are unknown, and model the process of detecting animals with unknown fates. This provides the foundation for our integrated model and permits necessary parameter estimation. We provide the Bayesian model, its derivation, and use simulation techniques to investigate the properties and performance of our approach under several scenarios. Lastly, we apply our estimation technique using a piece-wise constant hazard function to investigate the effects of year, age, chick size and sex, sex of the tending adult, and nesting habitat on mortality hazard rates of the endangered mountain plover (Charadrius montanus) chicks. Traditional models were inappropriate for this analysis because fates of some individual chicks were unknown due to failed radio transmitters. Simulations revealed biases of posterior mean estimates were minimal (≤ 4.95%), and posterior distributions behaved as expected with RMSE of the estimates decreasing as sample sizes, detection probability, and survival increased. We determined mortality hazard rates for plover chicks were highest at birth weights and/or whose nest was within agricultural habitats. Based on its performance, our approach greatly expands the range of problems for which event-time analyses can be used by eliminating the need for having completely known fate data.

  2. Exponential integrators in time-dependent density-functional calculations

    Science.gov (United States)

    Kidd, Daniel; Covington, Cody; Varga, Kálmán

    2017-12-01

    The integrating factor and exponential time differencing methods are implemented and tested for solving the time-dependent Kohn-Sham equations. Popular time propagation methods used in physics, as well as other robust numerical approaches, are compared to these exponential integrator methods in order to judge the relative merit of the computational schemes. We determine an improvement in accuracy of multiple orders of magnitude when describing dynamics driven primarily by a nonlinear potential. For cases of dynamics driven by a time-dependent external potential, the accuracy of the exponential integrator methods are less enhanced but still match or outperform the best of the conventional methods tested.

  3. Effects of varied doses of psilocybin on time interval reproduction in human subjects.

    Science.gov (United States)

    Wackermann, Jirí; Wittmann, Marc; Hasler, Felix; Vollenweider, Franz X

    2008-04-11

    Action of a hallucinogenic substance, psilocybin, on internal time representation was investigated in two double-blind, placebo-controlled studies: Experiment 1 with 12 subjects and graded doses, and Experiment 2 with 9 subjects and a very low dose. The task consisted in repeated reproductions of time intervals in the range from 1.5 to 5s. The effects were assessed by parameter kappa of the 'dual klepsydra' model of internal time representation, fitted to individual response data and intra-individually normalized with respect to initial values. The estimates kappa were in the same order of magnitude as in earlier studies. In both experiments, kappa was significantly increased by psilocybin at 90 min from the drug intake, indicating a higher loss rate of the internal duration representation. These findings are tentatively linked to qualitative alterations of subjective time in altered states of consciousness.

  4. Real-time digital x-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.

    1982-01-01

    The invention provides a method of producing visible difference images derived from an X-ray image of an anatomical subject, comprising the steps of directing X-rays through the anatomical subject for producing an image, converting the image into television fields comprising trains of on-going video signals, digitally storing and integrating the on-going video signals over a time interval corresponding to several successive television fields and thereby producing stored and integrated video signals, recovering the video signals from storage and producing integrated video signals, producing video difference signals by performing a subtraction between the integrated video signals and the on-going video signals outside the time interval, and converting the difference signals into visible television difference images representing on-going changes in the X-ray image

  5. Postprandial oxidative losses of dietary leucine depend on the time interval between consecutive meals

    NARCIS (Netherlands)

    Myszkowska-Ryciak, J.; Keller, J.S.; Bujko, J.; Stankiewicz-Ciupa, J.; Koopmanschap, R.E.; Schreurs, V.V.A.M.

    2015-01-01

    Postprandial oxidative losses of egg white-bound [1-13C]-leucine were studied as 13C recovery in the breath of rats in relation to different time intervals between two meals. Male Wistar rats (n = 48; 68.3 ±5.9 g) divided into 4 groups (n = 12) were fed two meals a day (9:00

  6. Effect of a data buffer on the recorded distribution of time intervals for random events

    Energy Technology Data Exchange (ETDEWEB)

    Barton, J C [Polytechnic of North London (UK)

    1976-03-15

    The use of a data buffer enables the distribution of the time intervals between events to be studied for times less than the recording system dead-time but the usual negative exponential distribution for random events has to be modified. The theory for this effect is developed for an n-stage buffer followed by an asynchronous recorder. Results are evaluated for the values of n from 1 to 5. In the language of queueing theory the system studied is of type M/D/1/n+1, i.e. with constant service time and a finite number of places.

  7. Dominant Lid Tectonics behaviour of continental lithosphere in Precambrian times: Palaeomagnetism confirms prolonged quasi-integrity and absence of supercontinent cycles

    Directory of Open Access Journals (Sweden)

    J.D.A. Piper

    2018-01-01

    Full Text Available Although Plate Tectonics cannot be effectively tested by palaeomagnetism in the Precambrian aeon due to the paucity of high precision poles spanning such a long time period, the possibility of Lid Tectonics is eminently testable because it seeks accordance of the wider dataset over prolonged intervals of time; deficiencies and complexities in the data merely contribute to dispersion. Accordance of palaeomagnetic poles across a quasi-integral continental crust for time periods of up to thousands of millions of years, together with recognition of very long intervals characterised by minimal polar motions (∼2.6–2.0, ∼1.5–1.25 and ∼0.75–0.6 Ga has been used to demonstrate that Lid Tectonics dominated this aeon. The new PALEOMAGIA database is used to refine a model for the Precambrian lid incorporating a large quasi-integral crescentric core running from South-Central Africa through Laurentia to Siberia with peripheral cratons subject to reorganisation at ∼2.1, ∼1.6 and ∼1.1 Ga. The model explains low levels of tidal friction, reduced heat balance, unique petrologic and isotopic signatures, and the prolonged crustal stability of Earth's “Middle Age”, whilst density concentrations of the palaeomagnetic poles show that the centre of the continental lid was persistently focussed near Earth's rotation axis from ∼2.8 to 0.6 Ga. The exception was the ∼2.7–2.2 Ga interval defined by ∼90° polar movements which translated the periphery of the lid to the rotation pole for this quasi-static period, a time characterised by glaciation and low levels of magmatic activity; the ∼2.7 Ga shift correlates with key interval of mid-Archaean crustal growth to some 60–70% of the present volume and REE signatures whilst the ∼2.2 Ga shift correlates with the Lomagundi δ13 C and Great Oxygenation events. The palaeomagnetic signature of breakup of the lid at ∼0.6 Ga is recorded by the world-wide Ediacaran development of passive

  8. Effect of insertion method and postinsertion time interval prior to force application on the removal torque of orthodontic miniscrews.

    Science.gov (United States)

    Sharifi, Maryam; Ghassemi, Amirreza; Bayani, Shahin

    2015-01-01

    Success of orthodontic miniscrews in providing stable anchorage is dependent on their stability. The purpose of this study was to assess the effect of insertion method and postinsertion time interval on the removal torque of miniscrews as an indicator of their stability. Seventy-two miniscrews (Jeil Medical) were inserted into the femoral bones of three male German Shepherd dogs and assigned to nine groups of eight miniscrews. Three insertion methods, including hand-driven, motor-driven with 5.0-Ncm insertion torque, and motor-driven with 20.0-Ncm insertion torque, were tested. Three time intervals of 0, 2, and 6 weeks between miniscrew insertion and removal were tested as well. Removal torque values were measured in newton centimeters by a removal torque tester (IMADA). Data were analyzed by one-way analysis of variance (ANOVA) followed by the Bonferroni post hoc test at a .05 level of significance. A miniscrew survival rate of 93% was observed in this study. The highest mean value of removal torque among the three postinsertion intervals (2.4 ± 0.59 Ncm) was obtained immediately after miniscrew insertion with a statistically significant difference from the other two time intervals (P torque values were obtained immediately after insertion.

  9. Evaluation of the Trail Making Test and interval timing as measures of cognition in healthy adults: comparisons by age, education, and gender.

    Science.gov (United States)

    Płotek, Włodzimierz; Łyskawa, Wojciech; Kluzik, Anna; Grześkowiak, Małgorzata; Podlewski, Roland; Żaba, Zbigniew; Drobnik, Leon

    2014-02-03

    Human cognitive functioning can be assessed using different methods of testing. Age, level of education, and gender may influence the results of cognitive tests. The well-known Trail Making Test (TMT), which is often used to measure the frontal lobe function, and the experimental test of Interval Timing (IT) were compared. The methods used in IT included reproduction of auditory and visual stimuli, with the subsequent production of the time intervals of 1-, 2-, 5-, and 7-seconds durations with no pattern. Subjects included 64 healthy adult volunteers aged 18-63 (33 women, 31 men). Comparisons were made based on age, education, and gender. TMT was performed quickly and was influenced by age, education, and gender. All reproduced visual and produced intervals were shortened and the reproduction of auditory stimuli was more complex. Age, education, and gender have more pronounced impact on the cognitive test than on the interval timing test. The reproduction of the short auditory stimuli was more accurate in comparison to other modalities used in the IT test. The interval timing, when compared to the TMT, offers an interesting possibility of testing. Further studies are necessary to confirm the initial observation.

  10. A comparison between brachial and echocardiographic systolic time intervals.

    Directory of Open Access Journals (Sweden)

    Ho-Ming Su

    Full Text Available Systolic time interval (STI is an established noninvasive technique for the assessment of cardiac function. Brachial STIs can be automatically determined by an ankle-brachial index (ABI-form device. The aims of this study are to evaluate whether the STIs measured from ABI-form device can represent those measured from echocardiography and to compare the diagnostic values of brachial and echocardiographic STIs in the prediction of left ventricular ejection fraction (LVEF <50%. A total of 849 patients were included in the study. Brachial pre-ejection period (bPEP and brachial ejection time (bET were measured using an ABI-form device and pre-ejection period (PEP and ejection time (ET were measured from echocardiography. Agreement was assessed by correlation coefficient and Bland-Altman plot. Brachial STIs had a significant correlation with echocardiographic STIs (r = 0.644, P<0.001 for bPEP and PEP; r  = 0.850, P<0.001 for bET and ET; r = 0.708, P<0.001 for bPEP/bET and PEP/ET. The disagreement between brachial and echocardiographic STIs (brachial STIs minus echocardiographic STIs was 28.55 ms for bPEP and PEP, -4.15 ms for bET and ET and -0.11 for bPEP/bET and PEP/ET. The areas under the curve for bPEP/bET and PEP/ET in the prediction of LVEF <50% were 0.771 and 0.765, respectively. Brachial STIs were good alternatives to STIs obtained from echocardiography and also helpful in prediction of LVEF <50%. Brachial STIs automatically obtained from an ABI-form device may be helpful for evaluation of left ventricular systolic dysfunction.

  11. Time interval between stroke onset and hospital arrival in acute ischemic stroke patients in Shanghai, China.

    Science.gov (United States)

    Fang, Jing; Yan, Weihong; Jiang, Guo-Xin; Li, Wei; Cheng, Qi

    2011-02-01

    To observe the time interval between stroke onset and hospital arrival (time-to-hospital) in acute ischemic stroke patients and analyze its putatively associated factors. During the period from November 1, 2006 to August 31, 2008, patients with acute ischemic stroke admitted consecutively to the Department of Neurology, Ninth Hospital, Shanghai, were enrolled in the study. Information of the patients was registered including the time-to-hospital, demographic data, history of stroke, season at attack, neurological symptom at onset, etc. Characteristics of the patients were analyzed and logistic regression analyses were conducted to identify factors associated with the time-to-hospital. There were 536 patients in the study, 290 (54.1%) males and 246 (45.9%) females. The median time-to-hospital was 8h (ranged from 0.1 to 300 h) for all patients. Within 3h after the onset of stroke, 162 patients (30.2%) arrived at our hospital; and within 6h, 278 patients (51.9%). Patients with a history of stroke, unconsciousness at onset, or a high NIHSS score at admission had significantly less time-to-hospital. The time interval between stroke onset and hospital arrival was importance of seeking immediate medical help after stroke onset of patients and their relatives could significantly influence their actions. Copyright © 2010 Elsevier B.V. All rights reserved.

  12. Time interval measurement between to emission: a systematics; Mesure de l`intervalle de temps entre deux emissions: une systematique

    Energy Technology Data Exchange (ETDEWEB)

    Bizard, G.; Bougault, R.; Brou, R.; Colin, J.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Kerambrun, A.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lopez, O.; Louvel, M.; Mahi, M.; Meslin, C.; Steckmeyer, J.C.; Tamain, B.; Wieloch, A. [Lab. de Physique Corpusculaire, Caen Univ., 14 (France); LPC (Caen) - CRN (Strasbourg) Collaboration

    1998-04-01

    A systematic study of the evolution of intervals of fragment emission times as a function of the energy deposited in the compound system was performed. Several measurements, Ne at 60 MeV/u, Ar at 30 and 60 MeV/u and two measurements for Kr at 60 MeV/u (central and semi-peripheral collisions) are presented. In all the experiments the target was Au and the mass of the compounds system was around A = 200. The excitation energies per nucleon reached in the case of these heavy systems cover the range of 3 to 5.5 MeV/u. The method used to determine the emission time intervals is based on the correlation functions associated to the relative angle distributions. The gaps between the data and simulations allow to evaluate the emission times. A rapid decrease of these time intervals was observed when the excitation energy increased. This variation starts at 500 fm/c which corresponds to a sequential emission. This relatively long time which indicates a weak interaction between fragments, corresponds practically to the measurement threshold. The shortest intervals (about 50 fm/c) are associated to a spontaneous multifragmentation and were observed in the case of central collisions at Ar+Au and Kr+Au at 60 MeV/u. Two interpretations are possible. The multifragmentation process might be viewed as a sequential process of very short time-separation or else, one can separate two zones heaving in mind that the multifragmentation is predominant from 4,5 MeV/u excitation energy upwards. This question is still open and its study is under way at LPC. An answer could come from the study of the rupture process of an excited nucleus, notably by the determination of its life-time

  13. Impact of a PACS/RIS-integrated speech recognition system on radiology reporting time and report availability

    International Nuclear Information System (INIS)

    Trumm, C.G.; Glaser, C.; Paasche, V.; Kuettner, B.; Francke, M.; Nissen-Meyer, S.; Reiser, M.; Crispin, A.; Popp, P.

    2006-01-01

    Purpose: Quantification of the impact of a PACS/RIS-integrated speech recognition system (SRS) on the time expenditure for radiology reporting and on hospital-wide report availability (RA) in a university institution. Material and Methods: In a prospective pilot study, the following parameters were assessed for 669 radiographic examinations (CR): 1. time requirement per report dictation (TED: dictation time (s)/number of images [examination] x number of words [report]) with either a combination of PACS/tape-based dictation (TD: analog dictation device/minicassette/transcription) or PACS/RIS/speech recognition system (RR: remote recognition/transcription and OR: online recognition/self-correction by radiologist), respectively, and 2. the Report Turnaround Time (RTT) as the time interval from the entry of the first image into the PACS to the available RIS/HIS report. Two equal time periods were chosen retrospectively from the RIS database: 11/2002-2/2003 (only TD) and 11/2003-2/2004 (only RR or OR with speech recognition system [SRS]). The midterm (≥24 h, 24 h intervals) and short-term (< 24 h, 1 h intervals), RA after examination completion were calculated for all modalities and for Cr, CT, MR and XA/DS separately. The relative increase in the mid-term RA (RIMRA: related to total number of examinations in each time period) and increase in the short-term RA (ISRA: ratio of available reports during the 1st to 24th hour) were calculated. Results: Prospectively, there was a significant difference between TD/RR/OR (n=151/257/261) regarding mean TED (0.44/0.54/0.62 s [per word and image]) and mean RTT (10.47/6.65/1.27 h), respectively. Retrospectively, 37 898/39 680 reports were computed from the RIS database for the time periods of 11/2002-2/2003 and 11/2003-2/2004. For CR/CT there was a shift of the short-term RA to the first 6 hours after examination completion (mean cumulative RA 20% higher) with a more than three-fold increase in the total number of available

  14. Cardiac time intervals and the association with 2D-speckle-tracking, tissue Doppler and conventional echocardiography

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Jensen, Jan Skov; Andersen, Henrik Ullits

    2016-01-01

    Cardiac time intervals (CTI) are prognostic above and beyond conventional echocardiographic measures. The explanation may be that CTI contain information about both systolic and diastolic measures; this is, however, unknown. The relationship between the CTI and systolic and diastolic function...

  15. Using hemoglobin A1C as a predicting model for time interval from pre-diabetes progressing to diabetes.

    Directory of Open Access Journals (Sweden)

    Chen-Ling Huang

    Full Text Available The early identification of subjects at high risk for diabetes is essential, thus, random rather than fasting plasma glucose is more useful. We aim to evaluate the time interval between pre-diabetes to diabetes with anti-diabetic drugs by using HbA1C as a diagnostic tool, and predicting it using a mathematic model.We used the Taipei Medical University Affiliated Hospital Patient Profile Database (AHPPD from January-2007 to June-2011. The patients who progressed and were prescribed anti-diabetic drugs were selected from AHPPD. The mathematical model used to predict the time interval of HbA1C value ranged from 5.7% to 6.5% for diabetes progression.We predicted an average overall time interval for all participants in between 5.7% to 6.5% during a total of 907 days (standard error, 103 days. For each group found among 5.7% to 6.5% we determined 1169.3 days for the low risk group (i.e. 3.2 years, 1080.5 days (i.e. 2.96 years for the increased risk group and 729.4 days (i.e. 1.99 years for the diabetes group. This indicates the patients will take an average of 2.49 years to reach 6.5%.This prediction model is very useful to help prioritize the diagnosis at an early stage for targeting individuals with risk of diabetes. Using patients' HbA1C before anti-diabetes drugs are used we predicted the time interval from pre-diabetes progression to diabetes is 2.49 years without any influence of age and gender. Additional studies are needed to support this model for a long term prediction.

  16. FSILP: fuzzy-stochastic-interval linear programming for supporting municipal solid waste management.

    Science.gov (United States)

    Li, Pu; Chen, Bing

    2011-04-01

    Although many studies on municipal solid waste management (MSW management) were conducted under uncertain conditions of fuzzy, stochastic, and interval coexistence, the solution to the conventional linear programming problems of integrating fuzzy method with the other two was inefficient. In this study, a fuzzy-stochastic-interval linear programming (FSILP) method is developed by integrating Nguyen's method with conventional linear programming for supporting municipal solid waste management. The Nguyen's method was used to convert the fuzzy and fuzzy-stochastic linear programming problems into the conventional linear programs, by measuring the attainment values of fuzzy numbers and/or fuzzy random variables, as well as superiority and inferiority between triangular fuzzy numbers/triangular fuzzy-stochastic variables. The developed method can effectively tackle uncertainties described in terms of probability density functions, fuzzy membership functions, and discrete intervals. Moreover, the method can also improve upon the conventional interval fuzzy programming and two-stage stochastic programming approaches, with advantageous capabilities that are easily achieved with fewer constraints and significantly reduces consumption time. The developed model was applied to a case study of municipal solid waste management system in a city. The results indicated that reasonable solutions had been generated. The solution can help quantify the relationship between the change of system cost and the uncertainties, which could support further analysis of tradeoffs between the waste management cost and the system failure risk. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Integration of MDSplus in real-time systems

    International Nuclear Information System (INIS)

    Luchetta, A.; Manduchi, G.; Taliercio, C.

    2006-01-01

    RFX-mod makes extensive usage of real-time systems for feedback control and uses MDSplus to interface them to the main Data Acquisition system. For this purpose, the core of MDSplus has been ported to VxWorks, the operating system used for real-time control in RFX. Using this approach, it is possible to integrate real-time systems, but MDSplus is used only for non-real-time tasks, i.e. those tasks which are executed before and after the pulse and whose performance does not affect the system time constraints. More extensive use of MDSplus in real-time systems is foreseen, and a real-time layer for MDSplus is under development, which will provide access to memory-mapped pulse files, shared by the tasks running on the same CPU. Real-time communication will also be integrated in the MDSplus core to provide support for distributed memory-mapped pulse files

  18. Multi-channel time-division integrator in HL-2A

    International Nuclear Information System (INIS)

    Yan Ji

    2008-01-01

    HL-2A is China's first Tokamak device with divertor configuration (magnetic confinement controlled nuclear fusion device). To find out the details of on-going fusion reaction at different times is of important significance in achieving controlled nuclear fusion. We developed a new type multi-channel time-division integrator for HL-2A. It has functions of automatic cutting off negative pulse of the input signals, optional integrating time division spacing 0.2-1 ms, TTL starting trigger signal, automatic regularly work 20 s, and integrating 10 channel at the same time. (authors)

  19. 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

  20. Deficits in Interval Timing Measured by the Dual-Task Paradigm among Children and Adolescents with Attention-Deficit/Hyperactivity Disorder

    Science.gov (United States)

    Hwang, Shoou-Lian; Gau, Susan Shur-Fen; Hsu, Wen-Yau; Wu, Yu-Yu

    2010-01-01

    Background: The underlying mechanism of time perception deficit in long time intervals in attention-deficit/hyperactivity disorder (ADHD) is still unclear. This study used the time reproduction dual task to explore the role of the attentional resource in time perception deficits among children and adolescents with ADHD. Methods: Participants…

  1. Continuous-time interval model identification of blood glucose dynamics for type 1 diabetes

    Science.gov (United States)

    Kirchsteiger, Harald; Johansson, Rolf; Renard, Eric; del Re, Luigi

    2014-07-01

    While good physiological models of the glucose metabolism in type 1 diabetic patients are well known, their parameterisation is difficult. The high intra-patient variability observed is a further major obstacle. This holds for data-based models too, so that no good patient-specific models are available. Against this background, this paper proposes the use of interval models to cover the different metabolic conditions. The control-oriented models contain a carbohydrate and insulin sensitivity factor to be used for insulin bolus calculators directly. Available clinical measurements were sampled on an irregular schedule which prompts the use of continuous-time identification, also for the direct estimation of the clinically interpretable factors mentioned above. An identification method is derived and applied to real data from 28 diabetic patients. Model estimation was done on a clinical data-set, whereas validation results shown were done on an out-of-clinic, everyday life data-set. The results show that the interval model approach allows a much more regular estimation of the parameters and avoids physiologically incompatible parameter estimates.

  2. Proceedings of Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting (23rd) held in Pasadena, California on December 3-5, 1991

    Science.gov (United States)

    1991-12-05

    Between Two Western European Time Laboratories and VNIIFTRI ............. 341 P Daly, University of Leeds, N.B. Koshelyaevsky, VNIIFTRI , and W Lewandowski...equipped with GPS time receivers and contributing to TAI. The last GPS antenna position determined by the BIPM is installed near Moscow in the VNIIFTRI : it...Leeds and VNIIFTRI ", accepted in Proc. 23rd Annual Precise Time and Time Interval (PTTI) Applications and Planning Meeting, 1991. 15. W. Lewandowski and

  3. First results from the INTEGRAL galactic plane scans

    DEFF Research Database (Denmark)

    Winkler, C.; Gehrels, N.; Schonfelder, V.

    2003-01-01

    Scans of the Galactic plane performed at regular intervals constitute a key element of the guaranteed time observations of the INTEGRAL observing programme. These scans are done for two reasons: frequent monitoring of the Galactic plane in order to detect transient sources, and time resolved mapp...... mapping of the Galactic plane in continuum and diffuse line emission. This paper describes first results obtained from the Galactic plane scans executed so far during the early phase (Dec. 2002-May 2003) of the nominal mission.......Scans of the Galactic plane performed at regular intervals constitute a key element of the guaranteed time observations of the INTEGRAL observing programme. These scans are done for two reasons: frequent monitoring of the Galactic plane in order to detect transient sources, and time resolved...

  4. 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

  5. DNA methylation results depend on DNA integrity – role of post mortem interval

    Directory of Open Access Journals (Sweden)

    Mathias eRhein

    2015-05-01

    Full Text Available Major questions of neurological and psychiatric mechanisms involve the brain functions on a molecular level and cannot be easily addressed due to limitations in access to tissue samples. Post mortem studies are able to partly bridge the gap between brain tissue research retrieved from animal trials and the information derived from peripheral analysis (e.g. measurements in blood cells in patients. Here, we wanted to know how fast DNA degradation is progressing under controlled conditions in order to define thresholds for tissue quality to be used in respective trials. Our focus was on the applicability of partly degraded samples for bisulfite sequencing and the determination of simple means to define cut-off values.After opening the brain cavity, we kept two consecutive pig skulls at ambient temperature (19-21°C and removed cortex tissue up to a post mortem interval (PMI of 120h. We calculated the percentage of degradation on DNA gel electrophoresis of brain DNA to estimate quality and relate this estimation spectrum to the quality of human post-mortem control samples. Functional DNA quality was investigated by bisulfite sequencing of two functionally relevant genes for either the serotonin receptor 5 (SLC6A4 or aldehyde dehydrogenase 2 (ALDH2.Testing our approach in a heterogeneous collective of human blood and brain samples, we demonstrate integrity of measurement quality below the threshold of 72h PMI.While sequencing technically worked for all timepoints irrespective of conceivable DNA degradation, there is a good correlation between variance of methylation to degradation levels documented in the gel (R2=0.4311, p=0.0392 for advancing post mortem intervals (PMI. This otherwise elusive phenomenon is an important prerequisite for the interpretation and evaluation of samples prior to in-depth processing via an affordable and easy assay to estimate identical sample quality and thereby comparable methylation measurements.

  6. Rapid determination of long-lived artificial alpha radionuclides using time interval analysis

    International Nuclear Information System (INIS)

    Uezu, Yasuhiro; Koarashi, Jun; Sanada, Yukihisa; Hashimoto, Tetsuo

    2003-01-01

    It is important to monitor long lived alpha radionuclides as plutonium ( 238 Pu, 239+240 Pu) in the field of working area and environment of nuclear fuel cycle facilities, because it is well known that potential risks of cancer-causing from alpha radiation is higher than gamma radiations. Thus, these monitoring are required high sensitivity, high resolution and rapid determination in order to measure a very low-level concentration of plutonium isotopes. In such high sensitive monitoring, natural radionuclides, including radon ( 222 Rn or 220 Rn) and their progenies, should be eliminated as low as possible. In this situation, a sophisticated discrimination method between Pu and progenies of 222 Rn or 220 Rn using time interval analysis (TIA), which was able to subtract short-lived radionuclides using the time interval distributions calculation of successive alpha and beta decay events within millisecond or microsecond orders, was designed and developed. In this system, alpha rays from 214 Po, 216 Po and 212 Po are extractable. TIA measuring system composes of Silicon Surface Barrier Detector (SSD), an amplifier, an Analog to Digital Converter (ADC), a Multi-Channel Analyzer (MCA), a high-resolution timer (TIMER), a multi-parameter collector and a personal computer. In ADC, incidental alpha and beta pulses are sent to the MCA and the TIMER simultaneously. Pulses from them are synthesized by the multi-parameter collector. After measurement, natural radionuclides are subtracted. Airborne particles were collected on membrane filter for 60 minutes at 100 L/min. Small Pu particles were added on the surface of it. Alpha and beta rays were measured and natural radionuclides were subtracted within 5 times of 145 msec. by TIA. As a result of it, the hidden Pu in natural background could be recognized clearly. The lower limit of determination of 239 Pu is calculated as 6x10 -9 Bq/cm 3 . This level is satisfied with the derived air concentration (DAC) of 239 Pu (8x10 -9 Bq/cm 3

  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. Time interval between cover crop termination and planting influences corn seedling disease, plant growth, and yield

    Science.gov (United States)

    Experiments were established in controlled and field environment to evaluate the effect of time intervals between cereal rye cover crop termination and corn planting on corn seedling disease, corn growth, and grain yield in 2014 and 2015. Rye termination dates ranged from 25 days before planting (DB...

  9. On solving wave equations on fixed bounded intervals involving Robin boundary conditions with time-dependent coefficients

    Science.gov (United States)

    van Horssen, Wim T.; Wang, Yandong; Cao, Guohua

    2018-06-01

    In this paper, it is shown how characteristic coordinates, or equivalently how the well-known formula of d'Alembert, can be used to solve initial-boundary value problems for wave equations on fixed, bounded intervals involving Robin type of boundary conditions with time-dependent coefficients. A Robin boundary condition is a condition that specifies a linear combination of the dependent variable and its first order space-derivative on a boundary of the interval. Analytical methods, such as the method of separation of variables (SOV) or the Laplace transform method, are not applicable to those types of problems. The obtained analytical results by applying the proposed method, are in complete agreement with those obtained by using the numerical, finite difference method. For problems with time-independent coefficients in the Robin boundary condition(s), the results of the proposed method also completely agree with those as for instance obtained by the method of separation of variables, or by the finite difference method.

  10. Interval selection with machine-dependent intervals

    OpenAIRE

    Bohmova K.; Disser Y.; Mihalak M.; Widmayer P.

    2013-01-01

    We study an offline interval scheduling problem where every job has exactly one associated interval on every machine. To schedule a set of jobs, exactly one of the intervals associated with each job must be selected, and the intervals selected on the same machine must not intersect.We show that deciding whether all jobs can be scheduled is NP-complete already in various simple cases. In particular, by showing the NP-completeness for the case when all the intervals associated with the same job...

  11. Time integration of tensor trains

    OpenAIRE

    Lubich, Christian; Oseledets, Ivan; Vandereycken, Bart

    2014-01-01

    A robust and efficient time integrator for dynamical tensor approximation in the tensor train or matrix product state format is presented. The method is based on splitting the projector onto the tangent space of the tensor manifold. The algorithm can be used for updating time-dependent tensors in the given data-sparse tensor train / matrix product state format and for computing an approximate solution to high-dimensional tensor differential equations within this data-sparse format. The formul...

  12. GENERIC Integrators: Structure Preserving Time Integration for Thermodynamic Systems

    Science.gov (United States)

    Öttinger, Hans Christian

    2018-04-01

    Thermodynamically admissible evolution equations for non-equilibrium systems are known to possess a distinct mathematical structure. Within the GENERIC (general equation for the non-equilibrium reversible-irreversible coupling) framework of non-equilibrium thermodynamics, which is based on continuous time evolution, we investigate the possibility of preserving all the structural elements in time-discretized equations. Our approach, which follows Moser's [1] construction of symplectic integrators for Hamiltonian systems, is illustrated for the damped harmonic oscillator. Alternative approaches are sketched.

  13. Numerical time integration for air pollution models

    NARCIS (Netherlands)

    J.G. Verwer (Jan); W. Hundsdorfer (Willem); J.G. Blom (Joke)

    1998-01-01

    textabstractDue to the large number of chemical species and the three space dimensions, off-the-shelf stiff ODE integrators are not feasible for the numerical time integration of stiff systems of advection-diffusion-reaction equations [ fracpar{c{t + nabla cdot left( vu{u c right) = nabla cdot left(

  14. The effect of complete integration of HIV and TB services on time to initiation of antiretroviral therapy: a before-after study.

    Directory of Open Access Journals (Sweden)

    Bernhard Kerschberger

    Full Text Available Studies have shown that early ART initiation in TB/HIV co-infected patients lowers mortality. One way to implement earlier ART commencement could be through integration of TB and HIV services, a more efficient model of care than separate, vertical programs. We present a model of full TB/HIV integration and estimate its effect on time to initiation of ART.We retrospectively reviewed TB registers and clinical notes of 209 TB/HIV co-infected adults with a CD4 count <250 cells/µl and registered for TB treatment at one primary care clinic in a South African township between June 2008 and May 2009. Using Kaplan-Meier and Cox proportional hazard analysis, we compared time between initiation of TB treatment and ART for the periods before and after full, "one-stop shop" integration of TB and HIV services (in December 2009. Potential confounders were determined a priori through directed acyclic graphs. Robustness of assumptions was investigated by sensitivity analyses. The analysis included 188 patients (100 pre- and 88 post-integration, yielding 56 person-years of observation. Baseline characteristics of the two groups were similar. Median time to ART initiation decreased from 147 days (95% confidence interval [CI] 85-188 before integration of services to 75 days (95% CI 52-119 post-integration. In adjusted analyses, patients attending the clinic post-integration were 1.60 times (95% CI 1.11-2.29 more likely to have started ART relative to the pre-integration period. Sensitivity analyses supported these findings.Full TB/HIV care integration is feasible and led to a 60% increased chance of co-infected patients starting ART, while reducing time to ART initiation by an average of 72 days. Although these estimates should be confirmed through larger studies, they suggest that scale-up of full TB/HIV service integration in high TB/HIV prevalence settings may shorten time to ART initiation, which might reduce excess mortality and morbidity.

  15. Integration time for the perception of depth from motion parallax.

    Science.gov (United States)

    Nawrot, Mark; Stroyan, Keith

    2012-04-15

    The perception of depth from relative motion is believed to be a slow process that "builds-up" over a period of observation. However, in the case of motion parallax, the potential accuracy of the depth estimate suffers as the observer translates during the viewing period. Our recent quantitative model for the perception of depth from motion parallax proposes that relative object depth (d) can be determined from retinal image motion (dθ/dt), pursuit eye movement (dα/dt), and fixation distance (f) by the formula: d/f≈dθ/dα. Given the model's dynamics, it is important to know the integration time required by the visual system to recover dα and dθ, and then estimate d. Knowing the minimum integration time reveals the incumbent error in this process. A depth-phase discrimination task was used to determine the time necessary to perceive depth-sign from motion parallax. Observers remained stationary and viewed a briefly translating random-dot motion parallax stimulus. Stimulus duration varied between trials. Fixation on the translating stimulus was monitored and enforced with an eye-tracker. The study found that relative depth discrimination can be performed with presentations as brief as 16.6 ms, with only two stimulus frames providing both retinal image motion and the stimulus window motion for pursuit (mean range=16.6-33.2 ms). This was found for conditions in which, prior to stimulus presentation, the eye was engaged in ongoing pursuit or the eye was stationary. A large high-contrast masking stimulus disrupted depth-discrimination for stimulus presentations less than 70-75 ms in both pursuit and stationary conditions. This interval might be linked to ocular-following response eye-movement latencies. We conclude that neural mechanisms serving depth from motion parallax generate a depth estimate much more quickly than previously believed. We propose that additional sluggishness might be due to the visual system's attempt to determine the maximum dθ/dα ratio

  16. Time step rescaling recovers continuous-time dynamical properties for discrete-time Langevin integration of nonequilibrium systems.

    Science.gov (United States)

    Sivak, David A; Chodera, John D; Crooks, Gavin E

    2014-06-19

    When simulating molecular systems using deterministic equations of motion (e.g., Newtonian dynamics), such equations are generally numerically integrated according to a well-developed set of algorithms that share commonly agreed-upon desirable properties. However, for stochastic equations of motion (e.g., Langevin dynamics), there is still broad disagreement over which integration algorithms are most appropriate. While multiple desiderata have been proposed throughout the literature, consensus on which criteria are important is absent, and no published integration scheme satisfies all desiderata simultaneously. Additional nontrivial complications stem from simulating systems driven out of equilibrium using existing stochastic integration schemes in conjunction with recently developed nonequilibrium fluctuation theorems. Here, we examine a family of discrete time integration schemes for Langevin dynamics, assessing how each member satisfies a variety of desiderata that have been enumerated in prior efforts to construct suitable Langevin integrators. We show that the incorporation of a novel time step rescaling in the deterministic updates of position and velocity can correct a number of dynamical defects in these integrators. Finally, we identify a particular splitting (related to the velocity Verlet discretization) that has essentially universally appropriate properties for the simulation of Langevin dynamics for molecular systems in equilibrium, nonequilibrium, and path sampling contexts.

  17. Geometric integrators for stochastic rigid body dynamics

    KAUST Repository

    Tretyakov, Mikhail

    2016-01-05

    Geometric integrators play an important role in simulating dynamical systems on long time intervals with high accuracy. We will illustrate geometric integration ideas within the stochastic context, mostly on examples of stochastic thermostats for rigid body dynamics. The talk will be mainly based on joint recent work with Rusland Davidchak and Tom Ouldridge.

  18. Geometric integrators for stochastic rigid body dynamics

    KAUST Repository

    Tretyakov, Mikhail

    2016-01-01

    Geometric integrators play an important role in simulating dynamical systems on long time intervals with high accuracy. We will illustrate geometric integration ideas within the stochastic context, mostly on examples of stochastic thermostats for rigid body dynamics. The talk will be mainly based on joint recent work with Rusland Davidchak and Tom Ouldridge.

  19. Approximations to the Probability of Failure in Random Vibration by Integral Equation Methods

    DEFF Research Database (Denmark)

    Nielsen, Søren R.K.; Sørensen, John Dalsgaard

    Close approximations to the first passage probability of failure in random vibration can be obtained by integral equation methods. A simple relation exists between the first passage probability density function and the distribution function for the time interval spent below a barrier before...... passage probability density. The results of the theory agree well with simulation results for narrow banded processes dominated by a single frequency, as well as for bimodal processes with 2 dominating frequencies in the structural response....... outcrossing. An integral equation for the probability density function of the time interval is formulated, and adequate approximations for the kernel are suggested. The kernel approximation results in approximate solutions for the probability density function of the time interval, and hence for the first...

  20. Conservative fourth-order time integration of non-linear dynamic systems

    DEFF Research Database (Denmark)

    Krenk, Steen

    2015-01-01

    An energy conserving time integration algorithm with fourth-order accuracy is developed for dynamic systems with nonlinear stiffness. The discrete formulation is derived by integrating the differential state-space equations of motion over the integration time increment, and then evaluating...... the resulting time integrals of the inertia and stiffness terms via integration by parts. This process introduces the time derivatives of the state space variables, and these are then substituted from the original state-space differential equations. The resulting discrete form of the state-space equations...... is a direct fourth-order accurate representation of the original differential equations. This fourth-order form is energy conserving for systems with force potential in the form of a quartic polynomial in the displacement components. Energy conservation for a force potential of general form is obtained...

  1. System Integration for Real-Time Mobile Manipulation

    Directory of Open Access Journals (Sweden)

    Reza Oftadeh

    2014-03-01

    Full Text Available Mobile manipulators are one of the most complicated types of mechatronics systems. The performance of these robots in performing complex manipulation tasks is highly correlated with the synchronization and integration of their low-level components. This paper discusses in detail the mechatronics design of a four wheel steered mobile manipulator. It presents the manipulator's mechanical structure and electrical interfaces, designs low-level software architecture based on embedded PC-based controls, and proposes a systematic solution based on code generation products of MATLAB and Simulink. The remote development environment described here is used to develop real-time controller software and modules for the mobile manipulator under a POSIX-compliant, real-time Linux operating system. Our approach enables developers to reliably design controller modules that meet the hard real-time constraints of the entire low-level system architecture. Moreover, it provides a systematic framework for the development and integration of hardware devices with various communication mediums and protocols, which facilitates the development and integration process of the software controller.

  2. An Integrative Data Science Pipeline to Identify Novel Drug Interactions that Prolong the QT Interval.

    Science.gov (United States)

    Lorberbaum, Tal; Sampson, Kevin J; Woosley, Raymond L; Kass, Robert S; Tatonetti, Nicholas P

    2016-05-01

    Drug-induced prolongation of the QT interval on the electrocardiogram (long QT syndrome, LQTS) can lead to a potentially fatal ventricular arrhythmia known as torsades de pointes (TdP). Over 40 drugs with both cardiac and non-cardiac indications are associated with increased risk of TdP, but drug-drug interactions contributing to LQTS (QT-DDIs) remain poorly characterized. Traditional methods for mining observational healthcare data are poorly equipped to detect QT-DDI signals due to low reporting numbers and lack of direct evidence for LQTS. We hypothesized that LQTS could be identified latently using an adverse event (AE) fingerprint of more commonly reported AEs. We aimed to generate an integrated data science pipeline that addresses current limitations by identifying latent signals for QT-DDIs in the US FDA's Adverse Event Reporting System (FAERS) and retrospectively validating these predictions using electrocardiogram data in electronic health records (EHRs). We trained a model to identify an AE fingerprint for risk of TdP for single drugs and applied this model to drug pair data to predict novel DDIs. In the EHR at Columbia University Medical Center, we compared the QTc intervals of patients prescribed the flagged drug pairs with patients prescribed either drug individually. We created an AE fingerprint consisting of 13 latently detected side effects. This model significantly outperformed a direct evidence control model in the detection of established interactions (p = 1.62E-3) and significantly enriched for validated QT-DDIs in the EHR (p = 0.01). Of 889 pairs flagged in FAERS, eight novel QT-DDIs were significantly associated with prolonged QTc intervals in the EHR and were not due to co-prescribed medications. Latent signal detection in FAERS validated using the EHR presents an automated and data-driven approach for systematically identifying novel QT-DDIs. The high-confidence hypotheses flagged using this method warrant further investigation.

  3. 33 CFR 150.503 - What are the time interval requirements for maintenance on survival craft falls?

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false What are the time interval requirements for maintenance on survival craft falls? 150.503 Section 150.503 Navigation and Navigable Waters... maintenance on survival craft falls? (a) Each fall used in a launching device for survival craft or rescue...

  4. Space-time transformations in radial path integrals

    International Nuclear Information System (INIS)

    Steiner, F.

    1984-09-01

    Nonlinear space-time transformations in the radial path integral are discussed. A transformation formula is derived, which relates the original path integral to the Green's function of a new quantum system with an effective potential containing an observable quantum correction proportional(h/2π) 2 . As an example the formula is applied to spherical Brownian motion. (orig.)

  5. Improving Music Genre Classification by Short-Time Feature Integration

    DEFF Research Database (Denmark)

    Meng, Anders; Ahrendt, Peter; Larsen, Jan

    2005-01-01

    Many different short-time features, using time windows in the size of 10-30 ms, have been proposed for music segmentation, retrieval and genre classification. However, often the available time frame of the music to make the actual decision or comparison (the decision time horizon) is in the range...... of seconds instead of milliseconds. The problem of making new features on the larger time scale from the short-time features (feature integration) has only received little attention. This paper investigates different methods for feature integration and late information fusion for music genre classification...

  6. Multisensory integration: the case of a time window of gesture-speech integration.

    Science.gov (United States)

    Obermeier, Christian; Gunter, Thomas C

    2015-02-01

    This experiment investigates the integration of gesture and speech from a multisensory perspective. In a disambiguation paradigm, participants were presented with short videos of an actress uttering sentences like "She was impressed by the BALL, because the GAME/DANCE...." The ambiguous noun (BALL) was accompanied by an iconic gesture fragment containing information to disambiguate the noun toward its dominant or subordinate meaning. We used four different temporal alignments between noun and gesture fragment: the identification point (IP) of the noun was either prior to (+120 msec), synchronous with (0 msec), or lagging behind the end of the gesture fragment (-200 and -600 msec). ERPs triggered to the IP of the noun showed significant differences for the integration of dominant and subordinate gesture fragments in the -200, 0, and +120 msec conditions. The outcome of this integration was revealed at the target words. These data suggest a time window for direct semantic gesture-speech integration ranging from at least -200 up to +120 msec. Although the -600 msec condition did not show any signs of direct integration at the homonym, significant disambiguation was found at the target word. An explorative analysis suggested that gesture information was directly integrated at the verb, indicating that there are multiple positions in a sentence where direct gesture-speech integration takes place. Ultimately, this would implicate that in natural communication, where a gesture lasts for some time, several aspects of that gesture will have their specific and possibly distinct impact on different positions in an utterance.

  7. Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies

    Directory of Open Access Journals (Sweden)

    Geue Daniel

    2004-04-01

    Full Text Available Abstract Background Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. Methods A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. Results Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p r2 = 0.66, p r2 = 0.21, p r2 = 0.13, p st week onward (p Conclusion We conclude that 1 from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2 the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3 fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.

  8. Quantifying uncertainty on sediment loads using bootstrap confidence intervals

    Science.gov (United States)

    Slaets, Johanna I. F.; Piepho, Hans-Peter; Schmitter, Petra; Hilger, Thomas; Cadisch, Georg

    2017-01-01

    Load estimates are more informative than constituent concentrations alone, as they allow quantification of on- and off-site impacts of environmental processes concerning pollutants, nutrients and sediment, such as soil fertility loss, reservoir sedimentation and irrigation channel siltation. While statistical models used to predict constituent concentrations have been developed considerably over the last few years, measures of uncertainty on constituent loads are rarely reported. Loads are the product of two predictions, constituent concentration and discharge, integrated over a time period, which does not make it straightforward to produce a standard error or a confidence interval. In this paper, a linear mixed model is used to estimate sediment concentrations. A bootstrap method is then developed that accounts for the uncertainty in the concentration and discharge predictions, allowing temporal correlation in the constituent data, and can be used when data transformations are required. The method was tested for a small watershed in Northwest Vietnam for the period 2010-2011. The results showed that confidence intervals were asymmetric, with the highest uncertainty in the upper limit, and that a load of 6262 Mg year-1 had a 95 % confidence interval of (4331, 12 267) in 2010 and a load of 5543 Mg an interval of (3593, 8975) in 2011. Additionally, the approach demonstrated that direct estimates from the data were biased downwards compared to bootstrap median estimates. These results imply that constituent loads predicted from regression-type water quality models could frequently be underestimating sediment yields and their environmental impact.

  9. Synchronization of Markovian jumping stochastic complex networks with distributed time delays and probabilistic interval discrete time-varying delays

    International Nuclear Information System (INIS)

    Li Hongjie; Yue Dong

    2010-01-01

    The paper investigates the synchronization stability problem for a class of complex dynamical networks with Markovian jumping parameters and mixed time delays. The complex networks consist of m modes and the networks switch from one mode to another according to a Markovian chain with known transition probability. The mixed time delays are composed of discrete and distributed delays, the discrete time delay is assumed to be random and its probability distribution is known a priori. In terms of the probability distribution of the delays, the new type of system model with probability-distribution-dependent parameter matrices is proposed. Based on the stochastic analysis techniques and the properties of the Kronecker product, delay-dependent synchronization stability criteria in the mean square are derived in the form of linear matrix inequalities which can be readily solved by using the LMI toolbox in MATLAB, the solvability of derived conditions depends on not only the size of the delay, but also the probability of the delay-taking values in some intervals. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the proposed method.

  10. Forecasting overhaul or replacement intervals based on estimated system failure intensity

    Science.gov (United States)

    Gannon, James M.

    1994-12-01

    System reliability can be expressed in terms of the pattern of failure events over time. Assuming a nonhomogeneous Poisson process and Weibull intensity function for complex repairable system failures, the degree of system deterioration can be approximated. Maximum likelihood estimators (MLE's) for the system Rate of Occurrence of Failure (ROCOF) function are presented. Evaluating the integral of the ROCOF over annual usage intervals yields the expected number of annual system failures. By associating a cost of failure with the expected number of failures, budget and program policy decisions can be made based on expected future maintenance costs. Monte Carlo simulation is used to estimate the range and the distribution of the net present value and internal rate of return of alternative cash flows based on the distributions of the cost inputs and confidence intervals of the MLE's.

  11. Reasoning about real-time systems with temporal interval logic constraints on multi-state automata

    Science.gov (United States)

    Gabrielian, Armen

    1991-01-01

    Models of real-time systems using a single paradigm often turn out to be inadequate, whether the paradigm is based on states, rules, event sequences, or logic. A model-based approach to reasoning about real-time systems is presented in which a temporal interval logic called TIL is employed to define constraints on a new type of high level automata. The combination, called hierarchical multi-state (HMS) machines, can be used to model formally a real-time system, a dynamic set of requirements, the environment, heuristic knowledge about planning-related problem solving, and the computational states of the reasoning mechanism. In this framework, mathematical techniques were developed for: (1) proving the correctness of a representation; (2) planning of concurrent tasks to achieve goals; and (3) scheduling of plans to satisfy complex temporal constraints. HMS machines allow reasoning about a real-time system from a model of how truth arises instead of merely depending of what is true in a system.

  12. INTEGRAL EDUCATION, TIME AND SPACE: PROBLEMATIZING CONCEPTS

    Directory of Open Access Journals (Sweden)

    Ana Elisa Spaolonzi Queiroz Assis

    2018-03-01

    Full Text Available Integral Education, despite being the subject of public policy agenda for some decades, still carries disparities related to its concept. In this sense, this article aims to problematize not only the concepts of integral education but also the categories time and space contained in the magazines Em Aberto. They were organized and published by the National Institute of Educational Studies Anísio Teixeira (INEP, numbers 80 (2009 and 88 (2012, respectively entitled "Educação Integral e tempo integral" and " Políticas de educação integral em jornada ampliada". The methodology is based on Bardin’s content analysis, respecting the steps of pre-analysis (research corpus formed by the texts in the journals; material exploration (reading the texts encoding data choosing the registration units for categorization; and processing and interpretation of results, based on Saviani’s Historical-Critical Pedagogy. The work reveals convergent and divergent conceptual multiplicity, provoking a discussion about a critical conception of integral education. Keywords: Integral Education. Historical-Critical Pedagogy. Content Analysis.

  13. Integration of Attributes from Non-Linear Characterization of Cardiovascular Time-Series for Prediction of Defibrillation Outcomes.

    Directory of Open Access Journals (Sweden)

    Sharad Shandilya

    Full Text Available The timing of defibrillation is mostly at arbitrary intervals during cardio-pulmonary resuscitation (CPR, rather than during intervals when the out-of-hospital cardiac arrest (OOH-CA patient is physiologically primed for successful countershock. Interruptions to CPR may negatively impact defibrillation success. Multiple defibrillations can be associated with decreased post-resuscitation myocardial function. We hypothesize that a more complete picture of the cardiovascular system can be gained through non-linear dynamics and integration of multiple physiologic measures from biomedical signals.Retrospective analysis of 153 anonymized OOH-CA patients who received at least one defibrillation for ventricular fibrillation (VF was undertaken. A machine learning model, termed Multiple Domain Integrative (MDI model, was developed to predict defibrillation success. We explore the rationale for non-linear dynamics and statistically validate heuristics involved in feature extraction for model development. Performance of MDI is then compared to the amplitude spectrum area (AMSA technique.358 defibrillations were evaluated (218 unsuccessful and 140 successful. Non-linear properties (Lyapunov exponent > 0 of the ECG signals indicate a chaotic nature and validate the use of novel non-linear dynamic methods for feature extraction. Classification using MDI yielded ROC-AUC of 83.2% and accuracy of 78.8%, for the model built with ECG data only. Utilizing 10-fold cross-validation, at 80% specificity level, MDI (74% sensitivity outperformed AMSA (53.6% sensitivity. At 90% specificity level, MDI had 68.4% sensitivity while AMSA had 43.3% sensitivity. Integrating available end-tidal carbon dioxide features into MDI, for the available 48 defibrillations, boosted ROC-AUC to 93.8% and accuracy to 83.3% at 80% sensitivity.At clinically relevant sensitivity thresholds, the MDI provides improved performance as compared to AMSA, yielding fewer unsuccessful defibrillations

  14. Path integral solution for some time-dependent potential

    International Nuclear Information System (INIS)

    Storchak, S.N.

    1989-12-01

    The quantum-mechanical problem with a time-dependent potential is solved by the path integral method. The solution is obtained by the application of the previously derived general formula for rheonomic homogeneous point transformation and reparametrization in the path integral. (author). 4 refs

  15. Energy drift in reversible time integration

    International Nuclear Information System (INIS)

    McLachlan, R I; Perlmutter, M

    2004-01-01

    Energy drift is commonly observed in reversible integrations of systems of molecular dynamics. We show that this drift can be modelled as a diffusion and that the typical energy error after time T is O(√T). (letter to the editor)

  16. Time-Lapse Measurement of Wellbore Integrity

    Science.gov (United States)

    Duguid, A.

    2017-12-01

    Well integrity is becoming more important as wells are used longer or repurposed. For CO2, shale gas, and other projects it has become apparent that wells represent the most likely unintended migration pathway for fluids out of the reservoir. Comprehensive logging programs have been employed to determine the condition of legacy wells in North America. These studies provide examples of assessment technologies. Logging programs have included pulsed neutron logging, ultrasonic well mapping, and cement bond logging. While these studies provide examples of what can be measured, they have only conducted a single round of logging and cannot show if the well has changed over time. Recent experience with time-lapse logging of three monitoring wells at a US Department of Energy sponsored CO2 project has shown the full value of similar tools. Time-lapse logging has shown that well integrity changes over time can be identified. It has also shown that the inclusion of and location of monitoring technologies in the well and the choice of construction materials must be carefully considered. Two of the wells were approximately eight years old at the time of study; they were constructed with steel and fiberglass casing sections and had lines on the outside of the casing running to the surface. The third well was 68 years old when it was studied and was originally constructed as a production well. Repeat logs were collected six or eight years after initial logging. Time-lapse logging showed the evolution of the wells. The results identified locations where cement degraded over time and locations that showed little change. The ultrasonic well maps show clearly that the lines used to connect the monitoring technology to the surface are visible and have a local effect on cement isolation. Testing and sampling was conducted along with logging. It provided insight into changes identified in the time-lapse log results. Point permeability testing was used to provide an in-situ point

  17. A study on assessment methodology of surveillance test interval and allowed outage time

    International Nuclear Information System (INIS)

    Che, Moo Seong; Cheong, Chang Hyeon; Lee, Byeong Cheol

    1996-07-01

    The objectives of this study is the development of methodology by which assessing the optimizes Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korea nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches is performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method

  18. A study on assessment methodology of surveillance test interval and allowed outage time

    Energy Technology Data Exchange (ETDEWEB)

    Che, Moo Seong; Cheong, Chang Hyeon; Lee, Byeong Cheol [Seoul Nationl Univ., Seoul (Korea, Republic of)] (and others)

    1996-07-15

    The objectives of this study is the development of methodology by which assessing the optimizes Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korea nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches is performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method.

  19. Recall intervals and time used for examination and prevention by dentists in child dental care in Denmark, Iceland, Norway and Sweden in 1996 and 2014

    DEFF Research Database (Denmark)

    Wang, N J; Petersen, P E; Sveinsdóttir, E G

    2018-01-01

    OBJECTIVE: The purpose of the present study was to explore intervals between regular dental examination and the time dentists spent for examination and preventive dental care of children in 1996 and 2014. PARTICIPANTS AND METHODS: In Denmark, Norway and Sweden, random samples of dentists working...... examinations in three of the four countries in 2014 than in 1996. CONCLUSIONS: This study of trends in dental care delivered by dentists during recent decades showed moves towards extended recall intervals and preventive care individualized according to caries risk. In addition, extending intervals could...... dentists used ample time delivering preventive care to children. Dentists reported spending significantly more time providing preventive care for caries risk children than for other children both in 1996 and 2014. Concurrent with extended intervals, dentists reported spending longer performing routine...

  20. Multiple-step fault estimation for interval type-II T-S fuzzy system of hypersonic vehicle with time-varying elevator faults

    Directory of Open Access Journals (Sweden)

    Jin Wang

    2017-03-01

    Full Text Available This article proposes a multiple-step fault estimation algorithm for hypersonic flight vehicles that uses an interval type-II Takagi–Sugeno fuzzy model. An interval type-II Takagi–Sugeno fuzzy model is developed to approximate the nonlinear dynamic system and handle the parameter uncertainties of hypersonic firstly. Then, a multiple-step time-varying additive fault estimation algorithm is designed to estimate time-varying additive elevator fault of hypersonic flight vehicles. Finally, the simulation is conducted in both aspects of modeling and fault estimation; the validity and availability of such method are verified by a series of the comparison of numerical simulation results.

  1. Comparison between time-step-integration and probabilistic methods in seismic analysis of a linear structure

    International Nuclear Information System (INIS)

    Schneeberger, B.; Breuleux, R.

    1977-01-01

    Assuming that earthquake ground motion is a stationary time function, the seismic analysis of a linear structure can be done by probailistic methods using the 'power spectral density function' (PSD), instead of applying the more traditional time-step-integration using earthquake time histories (TH). A given structure was analysed both by PSD and TH methods computing and comparing 'floor response spectra'. The analysis using TH was performed for two different TH and different frequency intervals for the 'floor-response-spectra'. The analysis using PSD first produced PSD functions of the responses of the floors and these were then converted into 'foor-response-spectra'. Plots of the resulting 'floor-response-spectra' show: (1) The agreement of TH and PSD results is quite close. (2) The curves produced by PSD are much smoother than those produced by TH and mostly form an enelope of the latter. (3) The curves produced by TH are quite jagged with the location and magnitude of the peaks depending on the choice of frequencies at which the 'floor-response-spectra' were evaluated and on the choice of TH. (Auth.)

  2. Assessment of time interval between tramadol intake and seizure and second drug-induced attack

    Directory of Open Access Journals (Sweden)

    Bahareh Abbasi

    2015-11-01

    Full Text Available Background: Tramadol is a synthetic drug which is prescribed in moderate and severe pain. Tramadol overdose can induce severe complications such as consciousness impairment and convulsions. This study was done to determine the convulsions incidence after tramadol use until one week after hospital discharge. Methods: This prospective study was done in tramadol overdose patients without uncontrolled epilepsy and head injury history. All cases admitted in Loghman and Rasol Akram Hospitals, Tehran, Iran from 1, April 2011 to 1, April 2012 were included and observed for at least 12 hours. Time interval between tramadol intake and first seizure were record. Then, patients with second drug-induced seizure were recognized and log time between the first and second seizure was analyzed. The patients were transferred to the intensive care unit (ICU if clinical worsening status observed. One week after hospital discharge, telephone follow-up was conducted. Results: A total of 150 patients with a history of tramadol induced seizures (141 men, 9 women, age: 23.23±5.94 years were enrolled in this study. Convulsion was seen in 104 patients (69.3%. In 8 out of 104 patients (7.6% two or more convulsion was seen. Time interval between tramadol use and the onset of the first and second seizure were 0.93±0.17 and 2.5±0.75 hours, respectively. Tramadol induced seizures are more likely to occur in males and patients with a history of drug abuse. Finally, one hundred forty nine patients (99.3% were discharged with good condition and the only one patient died from tramadol overdose. Conclusion: The results of the study showed tramadol induced seizure most frequently occurred within the first 4 hours of tramadol intake. The chance of experiencing a second seizure exists in the susceptible population. Thus, 4 hours after drug intake is the best time for patients to be hospital discharged.

  3. Delay-Dependent Stability Criterion for Bidirectional Associative Memory Neural Networks with Interval Time-Varying Delays

    Science.gov (United States)

    Park, Ju H.; Kwon, O. M.

    In the letter, the global asymptotic stability of bidirectional associative memory (BAM) neural networks with delays is investigated. The delay is assumed to be time-varying and belongs to a given interval. A novel stability criterion for the stability is presented based on the Lyapunov method. The criterion is represented in terms of linear matrix inequality (LMI), which can be solved easily by various optimization algorithms. Two numerical examples are illustrated to show the effectiveness of our new result.

  4. Optimal Data Interval for Estimating Advertising Response

    OpenAIRE

    Gerard J. Tellis; Philip Hans Franses

    2006-01-01

    The abundance of highly disaggregate data (e.g., at five-second intervals) raises the question of the optimal data interval to estimate advertising carryover. The literature assumes that (1) the optimal data interval is the interpurchase time, (2) too disaggregate data causes a disaggregation bias, and (3) recovery of true parameters requires assumption of the underlying advertising process. In contrast, we show that (1) the optimal data interval is what we call , (2) too disaggregate data do...

  5. Time resolved spectroscopy of GRB 030501 using INTEGRAL

    DEFF Research Database (Denmark)

    Beckmann, V.; Borkowski, J.; Courvoisier, T.J.L.

    2003-01-01

    The gamma-ray instruments on-board INTEGRAL offer an unique opportunity to perform time resolved analysis on GRBs. The imager IBIS allows accurate positioning of GRBs and broad band spectral analysis, while SPI provides high resolution spectroscopy. GRB 030501 was discovered by the INTEGRAL Burst...... the Ulysses and RHESSI experiments....

  6. The Influence of Pretreatment Characteristics and Radiotherapy Parameters on Time Interval to Development of Radiation-Associated Meningioma

    International Nuclear Information System (INIS)

    Paulino, Arnold C.; Ahmed, Irfan M.; Mai, Wei Y.; Teh, Bin S.

    2009-01-01

    Purpose: To identify pretreatment characteristics and radiotherapy parameters which may influence time interval to development of radiation-associated meningioma (RAM). Methods and Materials: A Medline/PUBMED search of articles dealing with RAM yielded 66 studies between 1981 and 2006. Factors analyzed included patient age and gender, type of initial tumor treated, radiotherapy (RT) dose and volume, and time interval from RT to development of RAM. Results: A total of 143 patients with a median age at RT of 12 years form the basis of this report. The most common initial tumors or conditions treated with RT were medulloblastoma (n = 27), pituitary adenoma (n = 20), acute lymphoblastic leukemia (n = 20), low-grade astrocytoma (n = 19), and tinea capitis (n = 14). In the 116 patients whose RT fields were known, 55 (47.4%) had a portion of the brain treated, whereas 32 (27.6%) and 29 (25.0%) had craniospinal and whole-brain fields. The median time from RT to develop a RAM or latent time (LT) was 19 years (range, 1-63 years). Male gender (p = 0.001), initial diagnosis of leukemia (p = 0.001), and use of whole brain or craniospinal field (p ≤ 0.0001) were associated with a shorter LT, whereas patients who received lower doses of RT had a longer LT (p < 0.0001). Conclusions: The latent time to develop a RAM was related to gender, initial tumor type, radiotherapy volume, and radiotherapy dose.

  7. Effect of the time interval between fusion and activation on epigenetic reprogramming and development of bovine somatic cell nuclear transfer embryos.

    Science.gov (United States)

    Liu, Jun; Wang, Yongsheng; Su, Jianmin; Wang, Lijun; Li, Ruizhe; Li, Qian; Wu, Yongyan; Hua, Song; Quan, Fusheng; Guo, Zekun; Zhang, Yong

    2013-04-01

    Previous studies have shown that the time interval between fusion and activation (FA interval) play an important role in nuclear remodeling and in vitro development of somatic cell nuclear transfer (SCNT) embryos. However, the effects of FA interval on the epigenetic reprogramming and in vivo developmental competence of SCNT embryos remain unknown. In the present study, the effects of different FA intervals (0 h, 2 h, and 4 h) on the epigenetic reprogramming and developmental competence of bovine SCNT embryos were assessed. The results demonstrated that H3 lysine 9 (H3K9ac) levels decreased rapidly after fusion in all three groups. H3K9ac was practically undetectable 2 h after fusion in the 2-h and 4-h FA interval groups. However, H3K9ac was still evidently detectable in the 0-h FA interval group. The H3K9ac levels increased 10 h after fusion in all three groups, but were higher in the 2-h and 4-h FA interval groups than that in the 0-h FA interval group. The methylation levels of the satellite I region in day-7 blastocysts derived from the 2-h or 4-h FA interval groups was similar to that of in vitro fertilization blastocysts and is significantly lower than that of the 0-h FA interval group. SCNT embryos derived from 2-h FA interval group showed higher developmental competence than those from the 0-h and 4-h FA interval groups in terms of cleavage rate, blastocyst formation rate, apoptosis index, and pregnancy and calving rates. Hence, the FA interval is an important factor influencing the epigenetic reprogramming and developmental competence of bovine SCNT embryos.

  8. Time-specific measurements of energy deposition from radiation fields in simulated sub-micron tissue volumes

    International Nuclear Information System (INIS)

    Famiano, M.A.

    1997-01-01

    A tissue-equivalent spherical proportional counter is used with a modified amplifier system to measure specific energy deposited from a uniform radiation field for short periods of time (∼1 micros to seconds) in order to extrapolate to dose in sub-micron tissue volumes. The energy deposited during these time intervals is compared to biological repair processes occurring within the same intervals after the initial energy deposition. The signal is integrated over a variable collection time which is adjusted with a square-wave pulse. Charge from particle passages is collected on the anode during the period in which the integrator is triggered, and the signal decays quickly to zero after the integrator feedback switch resets; the process repeats for every triggering pulse. Measurements of energy deposited from x rays, 137 Cs gamma rays, and electrons from a 90 Sr/ 90 Y source for various time intervals are taken. Spectral characteristics as a function of charge collection time are observed and frequency plots of specific energy and collection time-interval are presented. In addition, a threshold energy flux is selected for each radiation type at which the formation of radicals (based on current measurements) in mammalian cells equals the rate at which radicals are repaired

  9. Adaptive Changes After 2 Weeks of 10-s Sprint Interval Training With Various Recovery Times

    Directory of Open Access Journals (Sweden)

    Robert A. Olek

    2018-04-01

    Full Text Available Purpose: The aim of this study was to compare the effect of applying two different rest recovery times in a 10-s sprint interval training session on aerobic and anaerobic capacities as well as skeletal muscle enzyme activities.Methods: Fourteen physically active but not highly trained male subjects (mean maximal oxygen uptake 50.5 ± 1.0 mlO2·kg−1·min−1 participated in the study. The training protocol involved a series of 10-s sprints separated by either 1-min (SIT10:1 or 4-min (SIT10:4 of recovery. The number of sprints progressed from four to six over six sessions separated by 1–2 days rest. Pre and post intervention anthropometric measurements, assessment of aerobic, anaerobic capacity and muscle biopsy were performed. In the muscle samples maximal activities of citrate synthase (CS, 3-hydroxyacylCoA dehydrogenase (HADH, carnitine palmitoyl-transferase (CPT, malate dehydrogenase (MDH, and its mitochondrial form (mMDH, as well as lactate dehydrogenase (LDH were determined. Analysis of variance was performed to determine changes between conditions.Results: Maximal oxygen uptake improved significantly in both training groups, by 13.6% in SIT10:1 and 11.9% in SIT10:4, with no difference between groups. Wingate anaerobic test results indicated main effect of time for total work, peak power output and mean power output, which increased significantly and similarly in both groups. Significant differences between training groups were observed for end power output, which increased by 10.8% in SIT10:1, but remained unchanged in SIT10:4. Both training protocols induced similar increase in CS activity (main effect of time p < 0.05, but no other enzymes.Conclusion: Sprint interval training protocols induce metabolic adaptation over a short period of time, and the reduced recovery between bouts may attenuate fatigue during maximal exercise.

  10. Real-time digital X-ray subtraction imaging

    International Nuclear Information System (INIS)

    Mistretta, C.A.; Kruger, R.A.; Houk, T.L.

    1979-01-01

    A diagnostic anatomical X-ray apparatus comprising a converter and a television camera for converting an X-ray image of a subject into a series of television fields of video signals is described in detail. A digital memory system stores and integrates the video signals over a time interval corresponding to a plurality of successive television fields. The integrated video signals are recovered from storage and fed to a digital or analogue subtractor, the resulting output being displayed on a television monitor. Thus the display represents on-going changes in the anatomical X-ray image. In a modification, successive groups of fields are stored and integrated in three memories, cyclically, and subtractions are performed between successive pieces of integrated signals to provide a display of successive alterations in the X-ray image. For investigations of the heart, the integrating interval should be of the order of one cardiac cycle. (author)

  11. Time interval between maternal electrocardiogram and venous Doppler waves in normal pregnancy and preeclampsia: a pilot study.

    Science.gov (United States)

    Tomsin, K; Mesens, T; Molenberghs, G; Peeters, L; Gyselaers, W

    2012-12-01

    To evaluate the time interval between maternal electrocardiogram (ECG) and venous Doppler waves at different stages of uncomplicated pregnancy (UP) and in preeclampsia (PE). Cross-sectional pilot study in 40 uncomplicated singleton pregnancies, categorized in four groups of ten according to gestational age: 10 - 14 weeks (UP1), 18 - 23 weeks (UP2), 28 - 33 weeks (UP3) and ≥ 37 weeks (UP4) of gestation. A fifth group of ten women with PE was also included. A Doppler flow examination at the level of renal interlobar veins (RIV) and hepatic veins (HV) was performed according to a standard protocol, in association with a maternal ECG. The time interval between the ECG P-wave and the corresponding A-deflection of the venous Doppler waves was measured (PA), and expressed relative to the duration of the cardiac cycle (RR), and labeled PA/RR. In hepatic veins, the PA/RR is longer in UP 4 than in UP 1 (0.48 ± 0.15 versus 0.29 ± 0.09, p ≤ 0.001). When all UP groups were compared, the PA/RR increased gradually with gestational age. In PE, the HV PA/RR is shorter than in UP 3 (0.25 ± 0.09 versus 0.42 ± 0.14, p advanced gestational stages are consistent with known features of maternal cardiovascular adaptation. Shorter values in preeclampsia are consistent with maternal cardiovascular maladaptation mechanisms. Our pilot study invites more research of the relevance of the time interval between maternal ECG and venous Doppler waves as a new parameter for studying the gestational cardiovascular (patho)physiology of the maternal venous compartment by duplex sonography. © Georg Thieme Verlag KG Stuttgart · New York.

  12. Global Format for Conservative Time Integration in Nonlinear Dynamics

    DEFF Research Database (Denmark)

    Krenk, Steen

    2014-01-01

    The widely used classic collocation-based time integration procedures like Newmark, Generalized-alpha etc. generally work well within a framework of linear problems, but typically may encounter problems, when used in connection with essentially nonlinear structures. These problems are overcome....... In the present paper a conservative time integration algorithm is developed in a format using only the internal forces and the associated tangent stiffness at the specific time integration points. Thus, the procedure is computationally very similar to a collocation method, consisting of a series of nonlinear...... equivalent static load steps, easily implemented in existing computer codes. The paper considers two aspects: representation of nonlinear internal forces in a form that implies energy conservation, and the option of an algorithmic damping with the purpose of extracting energy from undesirable high...

  13. Explicit solution of Calderon preconditioned time domain integral equations

    KAUST Repository

    Ulku, Huseyin Arda

    2013-07-01

    An explicit marching on-in-time (MOT) scheme for solving Calderon-preconditioned time domain integral equations is proposed. The scheme uses Rao-Wilton-Glisson and Buffa-Christiansen functions to discretize the domain and range of the integral operators and a PE(CE)m type linear multistep to march on in time. Unlike its implicit counterpart, the proposed explicit solver requires the solution of an MOT system with a Gram matrix that is sparse and well-conditioned independent of the time step size. Numerical results demonstrate that the explicit solver maintains its accuracy and stability even when the time step size is chosen as large as that typically used by an implicit solver. © 2013 IEEE.

  14. Arthroscopic repair of massive contracted rotator cuff tears: aggressive release with anterior and posterior interval slides do not improve cuff healing and integrity.

    Science.gov (United States)

    Kim, Sung-Jae; Kim, Sung-Hwan; Lee, Su-Keon; Seo, Jae-Wan; Chun, Yong-Min

    2013-08-21

    Few studies of large-to-massive contracted rotator cuff tears have examined the arthroscopic complete repair obtained by a posterior interval slide and whether the clinical outcomes or structural integrity achieved are better than those after partial repair without the posterior interval slide. The study included forty-one patients with large-to-massive contracted rotator cuff tears, not amenable to complete repair with margin convergence alone. The patients underwent either arthroscopic complete repair with a posterior interval slide and side-to-side repair of the interval slide edge (twenty-two patients; Group P) or partial repair with margin convergence (nineteen patients; Group M). The patient assignment was not randomized. The Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES) score, University of California at Los Angeles (UCLA) shoulder score, and range of motion were used to compare the functional outcomes. Preoperative and six-month postoperative magnetic resonance arthrography (MRA) images were compared within or between groups. At the two-year follow-up evaluation, the SST, ASES score, UCLA score, and range of motion had significantly improved (p repair group with an aggressive release had no better clinical or structural outcomes compared with the partial repair group with margin convergence alone for large-to-massive contracted rotator cuff tears. In addition, the complete repair group had a 91% retear rate and a greater defect on follow-up MRA images. Even though this study had a relatively short-term follow-up, a complete repair of large-to-massive contracted rotator cuff tears, with an aggressive release such as posterior interval slide, may not have an increased benefit compared with partial repair without posterior interval slide.

  15. Time-varying spatial data integration and visualization: 4 Dimensions Environmental Observations Platform (4-DEOS)

    Science.gov (United States)

    Paciello, Rossana; Coviello, Irina; Filizzola, Carolina; Genzano, Nicola; Lisi, Mariano; Mazzeo, Giuseppe; Pergola, Nicola; Sileo, Giancanio; Tramutoli, Valerio

    2014-05-01

    In environmental studies the integration of heterogeneous and time-varying data, is a very common requirement for investigating and possibly visualize correlations among physical parameters underlying the dynamics of complex phenomena. Datasets used in such kind of applications has often different spatial and temporal resolutions. In some case superimposition of asynchronous layers is required. Traditionally the platforms used to perform spatio-temporal visual data analyses allow to overlay spatial data, managing the time using 'snapshot' data model, each stack of layers being labeled with different time. But this kind of architecture does not incorporate the temporal indexing neither the third spatial dimension which is usually given as an independent additional layer. Conversely, the full representation of a generic environmental parameter P(x,y,z,t) in the 4D space-time domain could allow to handle asynchronous datasets as well as less traditional data-products (e.g. vertical sections, punctual time-series, etc.) . In this paper we present the 4 Dimensions Environmental Observation Platform (4-DEOS), a system based on a web services architecture Client-Broker-Server. This platform is a new open source solution for both a timely access and an easy integration and visualization of heterogeneous (maps, vertical profiles or sections, punctual time series, etc.) asynchronous, geospatial products. The innovative aspect of the 4-DEOS system is that users can analyze data/products individually moving through time, having also the possibility to stop the display of some data/products and focus on other parameters for better studying their temporal evolution. This platform gives the opportunity to choose between two distinct display modes for time interval or for single instant. Users can choose to visualize data/products in two ways: i) showing each parameter in a dedicated window or ii) visualize all parameters overlapped in a single window. A sliding time bar, allows

  16. A CMOS integrated timing discriminator circuit for fast scintillation counters

    International Nuclear Information System (INIS)

    Jochmann, M.W.

    1998-01-01

    Based on a zero-crossing discriminator using a CR differentiation network for pulse shaping, a new CMOS integrated timing discriminator circuit is proposed for fast (t r ≥ 2 ns) scintillation counters at the cooler synchrotron COSY-Juelich. By eliminating the input signal's amplitude information by means of an analog continuous-time divider, a normalized pulse shape at the zero-crossing point is gained over a wide dynamic input amplitude range. In combination with an arming comparator and a monostable multivibrator this yields in a highly precise timing discriminator circuit, that is expected to be useful in different time measurement applications. First measurement results of a CMOS integrated logarithmic amplifier, which is part of the analog continuous-time divider, agree well with the corresponding simulations. Moreover, SPICE simulations of the integrated discriminator circuit promise a time walk well below 200 ps (FWHM) over a 40 dB input amplitude dynamic range

  17. An integrated technique for developing real-time systems

    NARCIS (Netherlands)

    Hooman, J.J.M.; Vain, J.

    1995-01-01

    The integration of conceptual modeling techniques, formal specification, and compositional verification is considered for real time systems within the knowledge engineering context. We define constructive transformations from a conceptual meta model to a real time specification language and give

  18. Path integration on space times with symmetry

    International Nuclear Information System (INIS)

    Low, S.G.

    1985-01-01

    Path integration on space times with symmetry is investigated using a definition of path integration of Gaussian integrators. Gaussian integrators, systematically developed using the theory of projective distributions, may be defined in terms of a Jacobi operator Green function. This definition of the path integral yields a semiclassical expansion of the propagator which is valid on caustics. The semiclassical approximation to the free particle propagator on symmetric and reductive homogeneous spaces is computed in terms of the complete solution of the Jacobi equation. The results are used to test the validity of using the Schwinger-DeWitt transform to compute an approximation to the coincidence limit of a field theory Green function from a WKB propagator. The method is found not to be valid except for certain special cases. These cases include manifolds constructed from the direct product of flat space and group manifolds, on which the free particle WKB approximation is exact and two sphere. The multiple geodesic contribution to 2 > on Schwarzschild in the neighborhood of rho = 3M is computed using the transform

  19. Socioeconomic position and the primary care interval

    DEFF Research Database (Denmark)

    Vedsted, Anders

    2018-01-01

    to the easiness to interpret the symptoms of the underlying cancer. Methods. We conducted a population-based cohort study using survey data on time intervals linked at an individually level to routine collected data on demographics from Danish registries. Using logistic regression we estimated the odds......Introduction. Diagnostic delays affect cancer survival negatively. Thus, the time interval from symptomatic presentation to a GP until referral to secondary care (i.e. primary care interval (PCI)), should be as short as possible. Lower socioeconomic position seems associated with poorer cancer...... younger than 45 years of age and older than 54 years of age had longer primary care interval than patients aged ‘45-54’ years. No other associations for SEP characteristics were observed. The findings may imply that GPs are referring patients regardless of SEP, although some room for improvement prevails...

  20. A New time Integration Scheme for Cahn-hilliard Equations

    KAUST Repository

    Schaefer, R.

    2015-06-01

    In this paper we present a new integration scheme that can be applied to solving difficult non-stationary non-linear problems. It is obtained by a successive linearization of the Crank- Nicolson scheme, that is unconditionally stable, but requires solving non-linear equation at each time step. We applied our linearized scheme for the time integration of the challenging Cahn-Hilliard equation, modeling the phase separation in fluids. At each time step the resulting variational equation is solved using higher-order isogeometric finite element method, with B- spline basis functions. The method was implemented in the PETIGA framework interfaced via the PETSc toolkit. The GMRES iterative solver was utilized for the solution of a resulting linear system at every time step. We also apply a simple adaptivity rule, which increases the time step size when the number of GMRES iterations is lower than 30. We compared our method with a non-linear, two stage predictor-multicorrector scheme, utilizing a sophisticated step length adaptivity. We controlled the stability of our simulations by monitoring the Ginzburg-Landau free energy functional. The proposed integration scheme outperforms the two-stage competitor in terms of the execution time, at the same time having a similar evolution of the free energy functional.

  1. A New time Integration Scheme for Cahn-hilliard Equations

    KAUST Repository

    Schaefer, R.; Smol-ka, M.; Dalcin, L; Paszyn'ski, M.

    2015-01-01

    In this paper we present a new integration scheme that can be applied to solving difficult non-stationary non-linear problems. It is obtained by a successive linearization of the Crank- Nicolson scheme, that is unconditionally stable, but requires solving non-linear equation at each time step. We applied our linearized scheme for the time integration of the challenging Cahn-Hilliard equation, modeling the phase separation in fluids. At each time step the resulting variational equation is solved using higher-order isogeometric finite element method, with B- spline basis functions. The method was implemented in the PETIGA framework interfaced via the PETSc toolkit. The GMRES iterative solver was utilized for the solution of a resulting linear system at every time step. We also apply a simple adaptivity rule, which increases the time step size when the number of GMRES iterations is lower than 30. We compared our method with a non-linear, two stage predictor-multicorrector scheme, utilizing a sophisticated step length adaptivity. We controlled the stability of our simulations by monitoring the Ginzburg-Landau free energy functional. The proposed integration scheme outperforms the two-stage competitor in terms of the execution time, at the same time having a similar evolution of the free energy functional.

  2. Initial Systolic Time Interval (ISTI) as a Predictor of Intradialytic Hypotension (IDH)

    International Nuclear Information System (INIS)

    Biesheuvel, J D; Verdaasdonk, R M; Meijer, JH; Vervloet, M G

    2013-01-01

    In haemodialysis treatment the clearance and volume control by the kidneys of a patient are partially replaced by intermittent haemodialysis. Because this artificial process is performed on a limited time scale, unphysiological imbalances in the fluid compartments of the body occur, that can lead to intradialytic hypotensions (IDH). An IDH endangers the efficacy of the haemodialysis session and is associated with dismal clinical endpoints, including mortality. A diagnostic method that predicts the occurrence of these drops in blood pressure could facilitate timely measures for the prevention of IDH. The present study investigates whether the Initial Systolic Time Interval (ISTI) can provide such a diagnostic method. The ISTI is defined as the time difference between the R-peak in the electrocardiogram (ECG) and the C-wave in the impedance cardiogram (ICG) and is considered to be a non-invasive assessment of the time delay between the electrical and mechanical activity of the heart. This time delay has previously been found to depend on autonomic nervous function as well as preload of the heart. Therefore, it can be expected that ISTI may predict an imminent IDH caused by a low circulating blood volume. This ongoing observational clinical study investigates the relationship between changes in ISTI and subsequent drops in blood pressure during haemodialysis. A registration of a complicated dialysis showed a significant correlation between a drop in blood pressure, a decrease in relative blood volume and a substantial increase in ISTI. An uncomplicated dialysis, in which also a considerable amount of fluid was removed, showed no correlations. Both, blood pressure and ISTI remained stable. In conclusion, the preliminary results of the present study show a substantial response of ISTI to haemodynamic instability, indicating an application in optimization and individualisation of the dialysis process.

  3. Neural Network Ensemble Based Approach for 2D-Interval Prediction of Solar Photovoltaic Power

    Directory of Open Access Journals (Sweden)

    Mashud Rana

    2016-10-01

    Full Text Available Solar energy generated from PhotoVoltaic (PV systems is one of the most promising types of renewable energy. However, it is highly variable as it depends on the solar irradiance and other meteorological factors. This variability creates difficulties for the large-scale integration of PV power in the electricity grid and requires accurate forecasting of the electricity generated by PV systems. In this paper we consider 2D-interval forecasts, where the goal is to predict summary statistics for the distribution of the PV power values in a future time interval. 2D-interval forecasts have been recently introduced, and they are more suitable than point forecasts for applications where the predicted variable has a high variability. We propose a method called NNE2D that combines variable selection based on mutual information and an ensemble of neural networks, to compute 2D-interval forecasts, where the two interval boundaries are expressed in terms of percentiles. NNE2D was evaluated for univariate prediction of Australian solar PV power data for two years. The results show that it is a promising method, outperforming persistence baselines and other methods used for comparison in terms of accuracy and coverage probability.

  4. Decoupling of modeling and measuring interval in groundwater time series analysis based on response characteristics

    NARCIS (Netherlands)

    Berendrecht, W.L.; Heemink, A.W.; Geer, F.C. van; Gehrels, J.C.

    2003-01-01

    A state-space representation of the transfer function-noise (TFN) model allows the choice of a modeling (input) interval that is smaller than the measuring interval of the output variable. Since in geohydrological applications the interval of the available input series (precipitation excess) is

  5. A semi-Markov model for stroke with piecewise-constant hazards in the presence of left, right and interval censoring.

    Science.gov (United States)

    Kapetanakis, Venediktos; Matthews, Fiona E; van den Hout, Ardo

    2013-02-20

    This paper presents a parametric method of fitting semi-Markov models with piecewise-constant hazards in the presence of left, right and interval censoring. We investigate transition intensities in a three-state illness-death model with no recovery. We relax the Markov assumption by adjusting the intensity for the transition from state 2 (illness) to state 3 (death) for the time spent in state 2 through a time-varying covariate. This involves the exact time of the transition from state 1 (healthy) to state 2. When the data are subject to left or interval censoring, this time is unknown. In the estimation of the likelihood, we take into account interval censoring by integrating out all possible times for the transition from state 1 to state 2. For left censoring, we use an Expectation-Maximisation inspired algorithm. A simulation study reflects the performance of the method. The proposed combination of statistical procedures provides great flexibility. We illustrate the method in an application by using data on stroke onset for the older population from the UK Medical Research Council Cognitive Function and Ageing Study. Copyright © 2012 John Wiley & Sons, Ltd.

  6. BiGGEsTS: integrated environment for biclustering analysis of time series gene expression data

    Directory of Open Access Journals (Sweden)

    Madeira Sara C

    2009-07-01

    Full Text Available Abstract Background The ability to monitor changes in expression patterns over time, and to observe the emergence of coherent temporal responses using expression time series, is critical to advance our understanding of complex biological processes. Biclustering has been recognized as an effective method for discovering local temporal expression patterns and unraveling potential regulatory mechanisms. The general biclustering problem is NP-hard. In the case of time series this problem is tractable, and efficient algorithms can be used. However, there is still a need for specialized applications able to take advantage of the temporal properties inherent to expression time series, both from a computational and a biological perspective. Findings BiGGEsTS makes available state-of-the-art biclustering algorithms for analyzing expression time series. Gene Ontology (GO annotations are used to assess the biological relevance of the biclusters. Methods for preprocessing expression time series and post-processing results are also included. The analysis is additionally supported by a visualization module capable of displaying informative representations of the data, including heatmaps, dendrograms, expression charts and graphs of enriched GO terms. Conclusion BiGGEsTS is a free open source graphical software tool for revealing local coexpression of genes in specific intervals of time, while integrating meaningful information on gene annotations. It is freely available at: http://kdbio.inesc-id.pt/software/biggests. We present a case study on the discovery of transcriptional regulatory modules in the response of Saccharomyces cerevisiae to heat stress.

  7. Considerations about expected a posteriori estimation in adaptive testing: adaptive a priori, adaptive correction for bias, and adaptive integration interval.

    Science.gov (United States)

    Raiche, Gilles; Blais, Jean-Guy

    2009-01-01

    In a computerized adaptive test, we would like to obtain an acceptable precision of the proficiency level estimate using an optimal number of items. Unfortunately, decreasing the number of items is accompanied by a certain degree of bias when the true proficiency level differs significantly from the a priori estimate. The authors suggest that it is possible to reduced the bias, and even the standard error of the estimate, by applying to each provisional estimation one or a combination of the following strategies: adaptive correction for bias proposed by Bock and Mislevy (1982), adaptive a priori estimate, and adaptive integration interval.

  8. Evaluation of time integration methods for transient response analysis of nonlinear structures

    International Nuclear Information System (INIS)

    Park, K.C.

    1975-01-01

    Recent developments in the evaluation of direct time integration methods for the transient response analysis of nonlinear structures are presented. These developments, which are based on local stability considerations of an integrator, show that the interaction between temporal step size and nonlinearities of structural systems has a pronounced effect on both accuracy and stability of a given time integration method. The resulting evaluation technique is applied to a model nonlinear problem, in order to: 1) demonstrate that it eliminates the present costly process of evaluating time integrator for nonlinear structural systems via extensive numerical experiments; 2) identify the desirable characteristics of time integration methods for nonlinear structural problems; 3) develop improved stiffly-stable methods for application to nonlinear structures. Extension of the methodology for examination of the interaction between a time integrator and the approximate treatment of nonlinearities (such as due to pseudo-force or incremental solution procedures) is also discussed. (Auth.)

  9. Conversion rate of laparoscopic cholecystectomy after endoscopic retrograde cholangiography in the treatment of choledocholithiasis - Does the time interval matter?

    NARCIS (Netherlands)

    de Vries, A.; Donkervoort, S. C.; van Geloven, A. A. W.; Pierik, E. G. J. M.

    2005-01-01

    Background: Preceding endoscopic retrograde cholangiography (ERC) in patients with choledochocystolithiasis impedes laparoscopic cholecystectomy (LC) and increases risk of conversion. We studied the influence of time interval between ERC and LC on the course of LC. Methods: All patients treated for

  10. Asymptotics for the Fredholm determinant of the sine kernel on a union of intervals

    Science.gov (United States)

    Widom, Harold

    1995-07-01

    In the bulk scaling limit of the Gaussian Unitary Ensemble of hermitian matrices the probability that an interval of length s contains no eigenvalues is the Fredholm determinant of the sine kernel{sin (x - y)}/{π (x - y)} over this interval. A formal asymptotic expansion for the determinant as s tends to infinity was obtained by Dyson. In this paper we replace a single interval of length s by sJ, where J is a union of m intervals and present a proof of the asymptotics up to second order. The logarithmic derivative with respect to s of the determinant equals a constant (expressible in terms of hyperelliptic integrals) times s, plus a bounded oscillatory function of s (zero if m=1, periodic if m=2, and in general expressible in terms of the solution of a Jacobi inversion problem), plus o(1). Also determined are the asymptotics of the trace of the resolvent operator, which is the ratio in the same model of the probability that the set contains exactly one eigenvalue to the probability that it contains none. The proofs use ideas from orthogonal polynomial theory.

  11. Integrals over products of distributions and coordinate independence of zero-temperature path integrals

    International Nuclear Information System (INIS)

    Kleinert, H.; Chervyakov, A.

    2003-01-01

    In perturbative calculations of quantum-statistical zero-temperature path integrals in curvilinear coordinates one encounters Feynman diagrams involving multiple temporal integrals over products of distributions, which are mathematically undefined. In addition, there are terms proportional to powers of Dirac δ-functions at the origin coming from the measure of path integration. We give simple rules for integrating products of distributions in such a way that the results ensure coordinate independence of the path integrals. The rules are derived by using equations of motion and partial integration, while keeping track of certain minimal features originating in the unique definition of all singular integrals in 1-ε dimensions. Our rules yield the same results as the much more cumbersome calculations in 1-ε dimensions where the limit ε→0 is taken at the end. They also agree with the rules found in an independent treatment on a finite time interval

  12. An integration time adaptive control method for atmospheric composition detection of occultation

    Science.gov (United States)

    Ding, Lin; Hou, Shuai; Yu, Fei; Liu, Cheng; Li, Chao; Zhe, Lin

    2018-01-01

    When sun is used as the light source for atmospheric composition detection, it is necessary to image sun for accurate identification and stable tracking. In the course of 180 second of the occultation, the magnitude of sun light intensity through the atmosphere changes greatly. It is nearly 1100 times illumination change between the maximum atmospheric and the minimum atmospheric. And the process of light change is so severe that 2.9 times per second of light change can be reached. Therefore, it is difficult to control the integration time of sun image camera. In this paper, a novel adaptive integration time control method for occultation is presented. In this method, with the distribution of gray value in the image as the reference variable, and the concepts of speed integral PID control, the integration time adaptive control problem of high frequency imaging. The large dynamic range integration time automatic control in the occultation can be achieved.

  13. Concurrent variable-interval variable-ratio schedules in a dynamic choice environment.

    Science.gov (United States)

    Bell, Matthew C; Baum, William M

    2017-11-01

    Most studies of operant choice have focused on presenting subjects with a fixed pair of schedules across many experimental sessions. Using these methods, studies of concurrent variable- interval variable-ratio schedules helped to evaluate theories of choice. More recently, a growing literature has focused on dynamic choice behavior. Those dynamic choice studies have analyzed behavior on a number of different time scales using concurrent variable-interval schedules. Following the dynamic choice approach, the present experiment examined performance on concurrent variable-interval variable-ratio schedules in a rapidly changing environment. Our objectives were to compare performance on concurrent variable-interval variable-ratio schedules with extant data on concurrent variable-interval variable-interval schedules using a dynamic choice procedure and to extend earlier work on concurrent variable-interval variable-ratio schedules. We analyzed performances at different time scales, finding strong similarities between concurrent variable-interval variable-interval and concurrent variable-interval variable- ratio performance within dynamic choice procedures. Time-based measures revealed almost identical performance in the two procedures compared with response-based measures, supporting the view that choice is best understood as time allocation. Performance at the smaller time scale of visits accorded with the tendency seen in earlier research toward developing a pattern of strong preference for and long visits to the richer alternative paired with brief "samples" at the leaner alternative ("fix and sample"). © 2017 Society for the Experimental Analysis of Behavior.

  14. The effect of finite response–time in coupled dynamical systems

    Indian Academy of Sciences (India)

    The paper investigates synchronization in unidirectionally coupled dynamical systems wherein the influence of drive on response is cumulative: coupling signals are integrated over a time interval . A major consequence of integrative coupling is that the onset of the generalized and phase synchronization occurs at higher ...

  15. The effect of finite response–time in coupled dynamical systems

    Indian Academy of Sciences (India)

    Abstract. The paper investigates synchronization in unidirectionally coupled dynamical systems wherein the influence of drive on response is cumulative: coupling signals are integrated over a time interval τ. A major consequence of integrative coupling is that the onset of the generalized and phase synchronization occurs ...

  16. Mixed time slicing in path integral simulations

    International Nuclear Information System (INIS)

    Steele, Ryan P.; Zwickl, Jill; Shushkov, Philip; Tully, John C.

    2011-01-01

    A simple and efficient scheme is presented for using different time slices for different degrees of freedom in path integral calculations. This method bridges the gap between full quantization and the standard mixed quantum-classical (MQC) scheme and, therefore, still provides quantum mechanical effects in the less-quantized variables. Underlying the algorithm is the notion that time slices (beads) may be 'collapsed' in a manner that preserves quantization in the less quantum mechanical degrees of freedom. The method is shown to be analogous to multiple-time step integration techniques in classical molecular dynamics. The algorithm and its associated error are demonstrated on model systems containing coupled high- and low-frequency modes; results indicate that convergence of quantum mechanical observables can be achieved with disparate bead numbers in the different modes. Cost estimates indicate that this procedure, much like the MQC method, is most efficient for only a relatively few quantum mechanical degrees of freedom, such as proton transfer. In this regime, however, the cost of a fully quantum mechanical simulation is determined by the quantization of the least quantum mechanical degrees of freedom.

  17. Optimal Real-time Dispatch for Integrated Energy Systems

    DEFF Research Database (Denmark)

    Anvari-Moghaddam, Amjad; Guerrero, Josep M.; Rahimi-Kian, Ashkan

    2016-01-01

    With the emerging of small-scale integrated energy systems (IESs), there are significant potentials to increase the functionality of a typical demand-side management (DSM) strategy and typical implementation of building-level distributed energy resources (DERs). By integrating DSM and DERs...... into a cohesive, networked package that fully utilizes smart energy-efficient end-use devices, advanced building control/automation systems, and integrated communications architectures, it is possible to efficiently manage energy and comfort at the end-use location. In this paper, an ontology-driven multi......-agent control system with intelligent optimizers is proposed for optimal real-time dispatch of an integrated building and microgrid system considering coordinated demand response (DR) and DERs management. The optimal dispatch problem is formulated as a mixed integer nonlinear programing problem (MINLP...

  18. VALIDATION OF SPRING OPERATED PRESSURE RELIEF VALVE TIME TO FAILURE AND THE IMPORTANCE OF STATISTICALLY SUPPORTED MAINTENANCE INTERVALS

    Energy Technology Data Exchange (ETDEWEB)

    Gross, R; Stephen Harris, S

    2009-02-18

    The Savannah River Site operates a Relief Valve Repair Shop certified by the National Board of Pressure Vessel Inspectors to NB-23, The National Board Inspection Code. Local maintenance forces perform inspection, testing, and repair of approximately 1200 spring-operated relief valves (SORV) each year as the valves are cycled in from the field. The Site now has over 7000 certified test records in the Computerized Maintenance Management System (CMMS); a summary of that data is presented in this paper. In previous papers, several statistical techniques were used to investigate failure on demand and failure rates including a quantal response method for predicting the failure probability as a function of time in service. The non-conservative failure mode for SORV is commonly termed 'stuck shut'; industry defined as the valve opening at greater than or equal to 1.5 times the cold set pressure. Actual time to failure is typically not known, only that failure occurred some time since the last proof test (censored data). This paper attempts to validate the assumptions underlying the statistical lifetime prediction results using Monte Carlo simulation. It employs an aging model for lift pressure as a function of set pressure, valve manufacturer, and a time-related aging effect. This paper attempts to answer two questions: (1) what is the predicted failure rate over the chosen maintenance/ inspection interval; and do we understand aging sufficient enough to estimate risk when basing proof test intervals on proof test results?

  19. Multichannel interval timer

    International Nuclear Information System (INIS)

    Turko, B.T.

    1983-10-01

    A CAMAC based modular multichannel interval timer is described. The timer comprises twelve high resolution time digitizers with a common start enabling twelve independent stop inputs. Ten time ranges from 2.5 μs to 1.3 μs can be preset. Time can be read out in twelve 24-bit words either via CAMAC Crate Controller or an external FIFO register. LSB time calibration is 78.125 ps. An additional word reads out the operational status of twelve stop channels. The system consists of two modules. The analog module contains a reference clock and 13 analog time stretchers. The digital module contains counters, logic and interface circuits. The timer has an excellent differential linearity, thermal stability and crosstalk free performance

  20. The effect of chorionicity and twin-to-twin delivery time interval on short-term outcome of the second twin

    DEFF Research Database (Denmark)

    Hjortø, Sofie; Nickelsen, Carsten; Petersen, Janne

    2013-01-01

    Abstract Objectives: To investigate the effect of chorionicity and twin-to-twin delivery time interval on short-term outcome in the second twin. Additionally, to investigate predictors of adverse outcome in both twins. Methods: Data included vaginally delivered twins (≥ 36 weeks) from Copenhagen ...

  1. Integrated circuits with emitter coupling and their application in nanosecond nuclear electronics

    International Nuclear Information System (INIS)

    Basiladze, S.G.

    1976-01-01

    Principal static and dynamic characteristics are considered of integrated circuits with emitter coupling, as well as problems of signal transmission. Diagrams are given of amplifiers, discriminators, time interval drivers, generators, etc. Systems and units of nanosecond electronics employing integrated circuits with emitter coupling are briefly described

  2. INTERVAL OBSERVER FOR A BIOLOGICAL REACTOR MODEL

    Directory of Open Access Journals (Sweden)

    T. A. Kharkovskaia

    2014-05-01

    Full Text Available The method of an interval observer design for nonlinear systems with parametric uncertainties is considered. The interval observer synthesis problem for systems with varying parameters consists in the following. If there is the uncertainty restraint for the state values of the system, limiting the initial conditions of the system and the set of admissible values for the vector of unknown parameters and inputs, the interval existence condition for the estimations of the system state variables, containing the actual state at a given time, needs to be held valid over the whole considered time segment as well. Conditions of the interval observers design for the considered class of systems are shown. They are: limitation of the input and state, the existence of a majorizing function defining the uncertainty vector for the system, Lipschitz continuity or finiteness of this function, the existence of an observer gain with the suitable Lyapunov matrix. The main condition for design of such a device is cooperativity of the interval estimation error dynamics. An individual observer gain matrix selection problem is considered. In order to ensure the property of cooperativity for interval estimation error dynamics, a static transformation of coordinates is proposed. The proposed algorithm is demonstrated by computer modeling of the biological reactor. Possible applications of these interval estimation systems are the spheres of robust control, where the presence of various types of uncertainties in the system dynamics is assumed, biotechnology and environmental systems and processes, mechatronics and robotics, etc.

  3. A delay-dependent approach to robust control for neutral uncertain neural networks with mixed interval time-varying delays

    International Nuclear Information System (INIS)

    Lu, Chien-Yu

    2011-01-01

    This paper considers the problem of delay-dependent global robust stabilization for discrete, distributed and neutral interval time-varying delayed neural networks described by nonlinear delay differential equations of the neutral type. The parameter uncertainties are norm bounded. The activation functions are assumed to be bounded and globally Lipschitz continuous. Using a Lyapunov functional approach and linear matrix inequality (LMI) techniques, the stability criteria for the uncertain neutral neural networks with interval time-varying delays are established in the form of LMIs, which can be readily verified using the standard numerical software. An important feature of the result reported is that all the stability conditions are dependent on the upper and lower bounds of the delays. Another feature of the results lies in that it involves fewer free weighting matrix strategy, and upper bounds of the inner product between two vectors are not introduced to reduce the conservatism of the criteria. Two illustrative examples are provided to demonstrate the effectiveness and the reduced conservatism of the proposed method

  4. Monolitic integrated circuit for the strobed charge-to-time converter

    International Nuclear Information System (INIS)

    Bel'skij, V.I.; Bushnin, Yu.B.; Zimin, S.A.; Punzhin, Yu.N.; Sen'ko, V.A.; Soldatov, M.M.; Tokarchuk, V.P.

    1985-01-01

    The developed and comercially produced semiconducting circuit - gating charge-to-time converter KR1101PD1 is described. The considered integrated circuit is a short pulse charge-to-time converter with integration of input current. The circuit is designed for construction of time-to-pulse analog-to-digital converters utilized in multichannel detection systems when studying complex topology processes. Input resistance of the circuit is 0.1 Ω permissible input current is 50 mA, maximum measured charge is 300-1000 pC

  5. High-intensity interval training: Modulating interval duration in overweight/obese men.

    Science.gov (United States)

    Smith-Ryan, Abbie E; Melvin, Malia N; Wingfield, Hailee L

    2015-05-01

    High-intensity interval training (HIIT) is a time-efficient strategy shown to induce various cardiovascular and metabolic adaptations. Little is known about the optimal tolerable combination of intensity and volume necessary for adaptations, especially in clinical populations. In a randomized controlled pilot design, we evaluated the effects of two types of interval training protocols, varying in intensity and interval duration, on clinical outcomes in overweight/obese men. Twenty-five men [body mass index (BMI) > 25 kg · m(2)] completed baseline body composition measures: fat mass (FM), lean mass (LM) and percent body fat (%BF) and fasting blood glucose, lipids and insulin (IN). A graded exercise cycling test was completed for peak oxygen consumption (VO2peak) and power output (PO). Participants were randomly assigned to high-intensity short interval (1MIN-HIIT), high-intensity interval (2MIN-HIIT) or control groups. 1MIN-HIIT and 2MIN-HIIT completed 3 weeks of cycling interval training, 3 days/week, consisting of either 10 × 1 min bouts at 90% PO with 1 min rests (1MIN-HIIT) or 5 × 2 min bouts with 1 min rests at undulating intensities (80%-100%) (2MIN-HIIT). There were no significant training effects on FM (Δ1.06 ± 1.25 kg) or %BF (Δ1.13% ± 1.88%), compared to CON. Increases in LM were not significant but increased by 1.7 kg and 2.1 kg for 1MIN and 2MIN-HIIT groups, respectively. Increases in VO2peak were also not significant for 1MIN (3.4 ml·kg(-1) · min(-1)) or 2MIN groups (2.7 ml · kg(-1) · min(-1)). IN sensitivity (HOMA-IR) improved for both training groups (Δ-2.78 ± 3.48 units; p < 0.05) compared to CON. HIIT may be an effective short-term strategy to improve cardiorespiratory fitness and IN sensitivity in overweight males.

  6. A Fully Integrated Discrete-Time Superheterodyne Receiver

    NARCIS (Netherlands)

    Tohidian, M.; Madadi, I.; Staszewski, R.B.

    2017-01-01

    The zero/low intermediate frequency (IF) receiver (RX) architecture has enabled full CMOS integration. As the technology scales and wireless standards become ever more challenging, the issues related to time-varying dc offsets, the second-order nonlinearity, and flicker noise become more critical.

  7. Optimal distribution of integration time for intensity measurements in Stokes polarimetry.

    Science.gov (United States)

    Li, Xiaobo; Liu, Tiegen; Huang, Bingjing; Song, Zhanjie; Hu, Haofeng

    2015-10-19

    We consider the typical Stokes polarimetry system, which performs four intensity measurements to estimate a Stokes vector. We show that if the total integration time of intensity measurements is fixed, the variance of the Stokes vector estimator depends on the distribution of the integration time at four intensity measurements. Therefore, by optimizing the distribution of integration time, the variance of the Stokes vector estimator can be decreased. In this paper, we obtain the closed-form solution of the optimal distribution of integration time by employing Lagrange multiplier method. According to the theoretical analysis and real-world experiment, it is shown that the total variance of the Stokes vector estimator can be significantly decreased about 40% in the case discussed in this paper. The method proposed in this paper can effectively decrease the measurement variance and thus statistically improves the measurement accuracy of the polarimetric system.

  8. Optimal order and time-step criterion for Aarseth-type N-body integrators

    International Nuclear Information System (INIS)

    Makino, Junichiro

    1991-01-01

    How the selection of the time-step criterion and the order of the integrator change the efficiency of Aarseth-type N-body integrators is discussed. An alternative to Aarseth's scheme based on the direct calculation of the time derivative of the force using the Hermite interpolation is compared to Aarseth's scheme, which uses the Newton interpolation to construct the predictor and corrector. How the number of particles in the system changes the behavior of integrators is examined. The Hermite scheme allows a time step twice as large as that for the standard Aarseth scheme for the same accuracy. The calculation cost of the Hermite scheme per time step is roughly twice as much as that of the standard Aarseth scheme. The optimal order of the integrators depends on both the particle number and the accuracy required. The time-step criterion of the standard Aarseth scheme is found to be inapplicable to higher-order integrators, and a more uniformly reliable criterion is proposed. 18 refs

  9. Interconnect rise time in superconducting integrating circuits

    International Nuclear Information System (INIS)

    Preis, D.; Shlager, K.

    1988-01-01

    The influence of resistive losses on the voltage rise time of an integrated-circuit interconnection is reported. A distribution-circuit model is used to present the interconnect. Numerous parametric curves are presented based on numerical evaluation of the exact analytical expression for the model's transient response. For the superconducting case in which the series resistance of the interconnect approaches zero, the step-response rise time is longer but signal strength increases significantly

  10. Extension of a chaos control method to unstable trajectories on infinite- or finite-time intervals: Experimental verification

    International Nuclear Information System (INIS)

    Yagasaki, Kazuyuki

    2007-01-01

    In experiments for single and coupled pendula, we demonstrate the effectiveness of a new control method based on dynamical systems theory for stabilizing unstable aperiodic trajectories defined on infinite- or finite-time intervals. The basic idea of the method is similar to that of the OGY method, which is a well-known, chaos control method. Extended concepts of the stable and unstable manifolds of hyperbolic trajectories are used here

  11. Novel global robust stability criteria for interval neural networks with multiple time-varying delays

    International Nuclear Information System (INIS)

    Xu Shengyuan; Lam, James; Ho, Daniel W.C.

    2005-01-01

    This Letter is concerned with the problem of robust stability analysis for interval neural networks with multiple time-varying delays and parameter uncertainties. The parameter uncertainties are assumed to be bounded in given compact sets and the activation functions are supposed to be bounded and globally Lipschitz continuous. A sufficient condition is obtained by means of Lyapunov functionals, which guarantees the existence, uniqueness and global asymptotic stability of the delayed neural network for all admissible uncertainties. This condition is in terms of a linear matrix inequality (LMI), which can be easily checked by using recently developed algorithms in solving LMIs. Finally, a numerical example is provided to demonstrate the effectiveness of the proposed method

  12. Aspects for Run-time Component Integration

    DEFF Research Database (Denmark)

    Truyen, Eddy; Jørgensen, Bo Nørregaard; Joosen, Wouter

    2000-01-01

    Component framework technology has become the cornerstone of building a family of systems and applications. A component framework defines a generic architecture into which specialized components can be plugged. As such, the component framework leverages the glue that connects the different inserted...... to dynamically integrate into the architecture of middleware systems new services that support non-functional aspects such as security, transactions, real-time....

  13. Influence Of Inspection Intervals On Mechanical System Reliability

    International Nuclear Information System (INIS)

    Zilberman, B.

    1998-01-01

    In this paper a methodology of reliability analysis of mechanical systems with latent failures is described. Reliability analysis of such systems must include appropriate usage of check intervals for latent failure detection. The methodology suggests, that based on system logic the analyst decides at the beginning if a system can fail actively or latently and propagates this approach through all system levels. All inspections are assumed to be perfect (all failures are detected and repaired and no new failures are introduced as a result of the maintenance). Additional assumptions are that mission time is much smaller, than check intervals and all components have constant failure rates. Analytical expressions for reliability calculates are provided, based on fault tree and Markov modeling techniques (for two and three redundant systems with inspection intervals). The proposed methodology yields more accurate results than are obtained by not using check intervals or using half check interval times. The conventional analysis assuming that at the beginning of each mission system is as new, give an optimistic prediction of system reliability. Some examples of reliability calculations of mechanical systems with latent failures and establishing optimum check intervals are provided

  14. THE DEVELOPMENT OF THE REAL TIME INTEGRATED TRAFFIC INFORMATION SYSTEM (RITIS FOR INDONESIA

    Directory of Open Access Journals (Sweden)

    Ofyar Z. TAMIN

    2001-01-01

    One of the most important information is the best routes from each origin zone to each destination zone which have already considered the effect of congestion. This information will be the main data for the development of the Route Guidance System (RGS so that each driver can choose his best route through the road network. The best route information will be changed in a short-time-interval basis depending on the traffic condition. Moreover, this approach can also be extended to provide the short-time-interval environmental information. The system has been tested and validated in Bandung and it showed remarkably good results for Bandung condition.

  15. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    largely unchanged during pregnancy, delivery, and postpartum and were within non-pregnant reference intervals. However, levels of fibrinogen, D-dimer, and coagulation factors VII, VIII, and IX increased markedly. Protein S activity decreased substantially, while free protein S decreased slightly and total......Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S...

  16. On the initial condition problem of the time domain PMCHWT surface integral equation

    KAUST Repository

    Uysal, Ismail Enes

    2017-05-13

    Non-physical, linearly increasing and constant current components are induced in marching on-in-time solution of time domain surface integral equations when initial conditions on time derivatives of (unknown) equivalent currents are not enforced properly. This problem can be remedied by solving the time integral of the surface integral for auxiliary currents that are defined to be the time derivatives of the equivalent currents. Then the equivalent currents are obtained by numerically differentiating the auxiliary ones. In this work, this approach is applied to the marching on-in-time solution of the time domain Poggio-Miller-Chan-Harrington-Wu-Tsai surface integral equation enforced on dispersive/plasmonic scatterers. Accuracy of the proposed method is demonstrated by a numerical example.

  17. Dedicated clock/timing-circuit theories of time perception and timed performance.

    Science.gov (United States)

    van Rijn, Hedderik; Gu, Bon-Mi; Meck, Warren H

    2014-01-01

    Scalar Timing Theory (an information-processing version of Scalar Expectancy Theory) and its evolution into the neurobiologically plausible Striatal Beat-Frequency (SBF) theory of interval timing are reviewed. These pacemaker/accumulator or oscillation/coincidence detection models are then integrated with the Adaptive Control of Thought-Rational (ACT-R) cognitive architecture as dedicated timing modules that are able to make use of the memory and decision-making mechanisms contained in ACT-R. The different predictions made by the incorporation of these timing modules into ACT-R are discussed as well as the potential limitations. Novel implementations of the original SBF model that allow it to be incorporated into ACT-R in a more fundamental fashion than the earlier simulations of Scalar Timing Theory are also considered in conjunction with the proposed properties and neural correlates of the "internal clock".

  18. Interval sampling methods and measurement error: a computer simulation.

    Science.gov (United States)

    Wirth, Oliver; Slaven, James; Taylor, Matthew A

    2014-01-01

    A simulation study was conducted to provide a more thorough account of measurement error associated with interval sampling methods. A computer program simulated the application of momentary time sampling, partial-interval recording, and whole-interval recording methods on target events randomly distributed across an observation period. The simulation yielded measures of error for multiple combinations of observation period, interval duration, event duration, and cumulative event duration. The simulations were conducted up to 100 times to yield measures of error variability. Although the present simulation confirmed some previously reported characteristics of interval sampling methods, it also revealed many new findings that pertain to each method's inherent strengths and weaknesses. The analysis and resulting error tables can help guide the selection of the most appropriate sampling method for observation-based behavioral assessments. © Society for the Experimental Analysis of Behavior.

  19. The influence of the anesthesia-to-stimulation time interval on seizure quality parameters in electroconvulsive therapy

    DEFF Research Database (Denmark)

    Jorgensen, A; Christensen, S J; Jensen, A E K

    2018-01-01

    BACKGROUND: Electroconvulsive therapy (ECT) continues to be the most efficacious treatment for severe depression and other life-threatening acute psychiatric conditions. Treatment efficacy is dependent upon the induced seizure quality, which may be influenced by a range of treatment related factors....... Recently, the time interval from anesthesia to the electrical stimulation (ASTI) has been suggested to be an important determinant of seizure quality. METHODS: We measured ASTI in 73 ECT sessions given to 22 individual patients, and analyzed its influence on five seizure quality parameters (EEG seizure...

  20. The Crank Nicolson Time Integrator for EMPHASIS.

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Duncan Alisdair Odum; Love, Edward; Kramer, Richard Michael Jack

    2018-03-01

    We investigate the use of implicit time integrators for finite element time domain approxi- mations of Maxwell's equations in vacuum. We discretize Maxwell's equations in time using Crank-Nicolson and in 3D space using compatible finite elements. We solve the system by taking a single step of Newton's method and inverting the Eddy-Current Schur complement allowing for the use of standard preconditioning techniques. This approach also generalizes to more complex material models that can include the Unsplit PML. We present verification results and demonstrate performance at CFL numbers up to 1000.

  1. Haemostatic reference intervals in pregnancy

    DEFF Research Database (Denmark)

    Szecsi, Pal Bela; Jørgensen, Maja; Klajnbard, Anna

    2010-01-01

    Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age-specific refe......Haemostatic reference intervals are generally based on samples from non-pregnant women. Thus, they may not be relevant to pregnant women, a problem that may hinder accurate diagnosis and treatment of haemostatic disorders during pregnancy. In this study, we establish gestational age......-specific reference intervals for coagulation tests during normal pregnancy. Eight hundred one women with expected normal pregnancies were included in the study. Of these women, 391 had no complications during pregnancy, vaginal delivery, or postpartum period. Plasma samples were obtained at gestational weeks 13......-20, 21-28, 29-34, 35-42, at active labor, and on postpartum days 1 and 2. Reference intervals for each gestational period using only the uncomplicated pregnancies were calculated in all 391 women for activated partial thromboplastin time (aPTT), fibrinogen, fibrin D-dimer, antithrombin, free protein S...

  2. On the relationship between supplier integration and time-to-market

    NARCIS (Netherlands)

    Perols, J.; Zimmermann, C.; Kortmann, S.

    2013-01-01

    Recent operations management and innovation management research emphasizes the importance of supplier integration. However, the empirical results as to the relationship between supplier integration and time-to-market are ambivalent. To understand this important relationship, we incorporate two major

  3. Integrals of Motion for Discrete-Time Optimal Control Problems

    OpenAIRE

    Torres, Delfim F. M.

    2003-01-01

    We obtain a discrete time analog of E. Noether's theorem in Optimal Control, asserting that integrals of motion associated to the discrete time Pontryagin Maximum Principle can be computed from the quasi-invariance properties of the discrete time Lagrangian and discrete time control system. As corollaries, results for first-order and higher-order discrete problems of the calculus of variations are obtained.

  4. Time integration in the code Zgoubi and external usage of PTC's structures

    International Nuclear Information System (INIS)

    Forest, Etienne; Meot, F.

    2006-06-01

    The purpose of this note is to describe Zgoubi's integrator and to describe some pitfalls for time based integration when used in accelerators. We show why the convergence rate of an integrator can be affected by an improper treatment at the boundary when time is used as the integration variable. We also point out how the code PTC can be used as a container by other tracking engine. This work is not completed as far as incorporation of Zgoubi is concerned. (authors)

  5. The impact of the time interval on in-vitro fertilisation success after failure of the first attempt.

    Science.gov (United States)

    Bayoglu Tekin, Y; Ceyhan, S T; Kilic, S; Korkmaz, C

    2015-05-01

    The aim of this study was to identify the optimal time interval for in-vitro fertilisation that would increase treatment success after failure of the first attempt. This retrospective study evaluated 454 consecutive cycles of 227 infertile women who had two consecutive attempts within a 6-month period at an IVF centre. Data were collected on duration of stimulation, consumption of gonadotropin, numbers of retrieved oocytes, mature oocytes, fertilised eggs, good quality embryos on day 3/5 following oocyte retrieval and clinical and ongoing pregnancy. There were significant increases in clinical pregnancy rates at 2-, 3- and 4-month intervals. The maximum increase was after two menstrual cycles (p = 0.001). The highest rate of ongoing pregnancy was in women that had the second attempt after the next menstrual cycle following failure of IVF (27.2%). After IVF failure, initiating the next attempt within 2-4 months increases the clinical pregnancy rates.

  6. Non-integrability of time-dependent spherically symmetric Yang-Mills equations

    Energy Technology Data Exchange (ETDEWEB)

    Matinyan, S G; Prokhorenko, E B; Savvidy, G K

    1988-03-07

    The integrability of time-dependent spherically symmetric Yang-Mills equations is studied using the Fermi-Pasta-Ulam method. It is shown that the motion of this system is ergodic, while the system itself is non-integrable, i.e. manifests dynamical chaos.

  7. Semi-Markov models for interval censored transient cognitive states with back transitions and a competing risk.

    Science.gov (United States)

    Wei, Shaoceng; Kryscio, Richard J

    2016-12-01

    Continuous-time multi-state stochastic processes are useful for modeling the flow of subjects from intact cognition to dementia with mild cognitive impairment and global impairment as intervening transient cognitive states and death as a competing risk. Each subject's cognition is assessed periodically resulting in interval censoring for the cognitive states while death without dementia is not interval censored. Since back transitions among the transient states are possible, Markov chains are often applied to this type of panel data. In this manuscript, we apply a semi-Markov process in which we assume that the waiting times are Weibull distributed except for transitions from the baseline state, which are exponentially distributed and in which we assume no additional changes in cognition occur between two assessments. We implement a quasi-Monte Carlo (QMC) method to calculate the higher order integration needed for likelihood estimation. We apply our model to a real dataset, the Nun Study, a cohort of 461 participants. © The Author(s) 2014.

  8. Yield and quality of milk and udder health in Martina Franca ass: effects of daily interval and time of machine milking

    Directory of Open Access Journals (Sweden)

    Giovanni Martemucci

    2010-01-01

    Full Text Available Twenty asses of Martina Franca breed, machine milked twice a day, were used to assess the influence of milking interval (3-h, 5-h, and 8-h; N=5 and time (700, 1200 and 1900 on milk yield and udder health. Individual milk samples were taken to determine fat, protein and lactose con- tent. Sensory analysis profile was also assessed. Milk’s total bacterial count (TBC, somatic cell con- tent (SCC and udder’s skin temperature were considered to assess udder health. Milk yield increases by 28.4% (P<0.01 with a milking interval from 3-h to 8-h and is higher (P<0.01 at morning milking. The maximum milk yield per milking corresponds to 700 milking (1416.9 mL thus indicating a circa- dian rhythm in milk secretion processes. Milking intervals of 5 and 8 hours cause a decrease (P<0.01 in milk fat and lactose content. The 8-h interval leads to an increase (P<0.01 in SCC but without any significance for the health udder. No alterations about CBT, clinical evaluation and temperature of ud- der were observed. Milk organoleptic characteristics were better in the 3-h interval milking.

  9. Parareal algorithms with local time-integrators for time fractional differential equations

    Science.gov (United States)

    Wu, Shu-Lin; Zhou, Tao

    2018-04-01

    It is challenge work to design parareal algorithms for time-fractional differential equations due to the historical effect of the fractional operator. A direct extension of the classical parareal method to such equations will lead to unbalance computational time in each process. In this work, we present an efficient parareal iteration scheme to overcome this issue, by adopting two recently developed local time-integrators for time fractional operators. In both approaches, one introduces auxiliary variables to localized the fractional operator. To this end, we propose a new strategy to perform the coarse grid correction so that the auxiliary variables and the solution variable are corrected separately in a mixed pattern. It is shown that the proposed parareal algorithm admits robust rate of convergence. Numerical examples are presented to support our conclusions.

  10. A Novel Multiple-Time Scale Integrator for the Hybrid Monte Carlo Algorithm

    International Nuclear Information System (INIS)

    Kamleh, Waseem

    2011-01-01

    Hybrid Monte Carlo simulations that implement the fermion action using multiple terms are commonly used. By the nature of their formulation they involve multiple integration time scales in the evolution of the system through simulation time. These different scales are usually dealt with by the Sexton-Weingarten nested leapfrog integrator. In this scheme the choice of time scales is somewhat restricted as each time step must be an exact multiple of the next smallest scale in the sequence. A novel generalisation of the nested leapfrog integrator is introduced which allows for far greater flexibility in the choice of time scales, as each scale now must only be an exact multiple of the smallest step size.

  11. Numerical counting ratemeter with variable time constant and integrated circuits

    International Nuclear Information System (INIS)

    Kaiser, J.; Fuan, J.

    1967-01-01

    We present here the prototype of a numerical counting ratemeter which is a special version of variable time-constant frequency meter (1). The originality of this work lies in the fact that the change in the time constant is carried out automatically. Since the criterion for this change is the accuracy in the annunciated result, the integration time is varied as a function of the frequency. For the prototype described in this report, the time constant varies from 1 sec to 1 millisec. for frequencies in the range 10 Hz to 10 MHz. This prototype is built entirely of MECL-type integrated circuits from Motorola and is thus contained in two relatively small boxes. (authors) [fr

  12. Precise digital integration in wide time range: theory and realization

    International Nuclear Information System (INIS)

    Batrakov, A.M.; Pavlenko, A.V.

    2017-01-01

    The digital integration method based on using high-speed precision analog-to-digital converters (ADC) has become widely used over the recent years. The paper analyzes the limitations of this method that are caused by the signal properties, ADC sampling rate and noise spectral density of the ADC signal path. This analysis allowed creating digital integrators with accurate synchronization and achieving an integration error of less than 10 −5 in the time range from microseconds to tens of seconds. The structure of the integrator is described and its basic parameters are presented. The possibilities of different ADC chips in terms of their applicability to digital integrators are discussed. A comparison with other integrating devices is presented.

  13. OPTIMASI OLSR ROUTING PROTOCOL PADA JARINGAN WIRELESS MESH DENGAN ADAPTIVE REFRESHING TIME INTERVAL DAN ENHANCE MULTI POINT RELAY SELECTING ALGORITHM

    Directory of Open Access Journals (Sweden)

    Faosan Mapa

    2014-01-01

    Full Text Available Normal 0 false false false IN X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Wireless Mesh Network (WMN adalah suatu konektivitas jaringan yang self-organized, self-configured dan multi-hop. Tujuan dari WMN adalah menawarkan pengguna suatu bentuk jaringan nirkabel yang dapat dengan mudah berkomunikasi dengan jaringan konvensional dengan kecepatan tinggi dan dengan cakupan yang lebih luas serta biaya awal yang minimal. Diperlukan suatu desain protokol routing yang efisien untuk WMN yang secara adaptif dapat mendukung mesh routers dan mesh clients. Dalam tulisan ini, diusulkan untuk mengoptimalkan protokol OLSR, yang merupakan protokol routing proaktif. Digunakan heuristik yang meningkatkan protokol OLSR melalui adaptive refreshing time interval dan memperbaiki metode MPR selecting algorithm. Suatu analisa dalam meningkatkan protokol OLSR melalui adaptive refreshing time interval dan memperbaiki algoritma pemilihan MPR menunjukkan kinerja yang signifikan dalam hal throughput jika dibandingkan dengan protokol OLSR yang asli. Akan tetapi, terdapat kenaikan dalam hal delay. Pada simulasi yang dilakukan dapat disimpulkan bahwa OLSR dapat dioptimalkan dengan memodifikasi pemilihan node MPR berdasarkan cost effective dan penyesuaian waktu interval refreshing hello message sesuai dengan keadaan

  14. Numerical Time Integration Methods for a Point Absorber Wave Energy Converter

    DEFF Research Database (Denmark)

    Zurkinden, Andrew Stephen; Kramer, Morten

    2012-01-01

    on a discretization of the convolution integral. The calculation of the convolution integral is performed at each time step regardless of the chosen numerical scheme. In the second model the convolution integral is replaced by a system of linear ordinary differential equations. The formulation of the state...

  15. Right Propositional Neighborhood Logic over Natural Numbers with Integer Constraints for Interval Lengths

    DEFF Research Database (Denmark)

    Bresolin, Davide; Goranko, Valentin; Montanari, Angelo

    2009-01-01

    Interval temporal logics are based on interval structures over linearly (or partially) ordered domains, where time intervals, rather than time instants, are the primitive ontological entities. In this paper we introduce and study Right Propositional Neighborhood Logic over natural numbers...... with integer constraints for interval lengths, which is a propositional interval temporal logic featuring a modality for the 'right neighborhood' relation between intervals and explicit integer constraints for interval lengths. We prove that it has the bounded model property with respect to ultimately periodic...

  16. Feasibility of real-time calculation of correlation integral derived statistics applied to EGG time series

    NARCIS (Netherlands)

    van den Broek, PLC; van Egmond, J; van Rijn, CM; Takens, F; Coenen, AML; Booij, LHDJ

    2005-01-01

    Background: This study assessed the feasibility of online calculation of the correlation integral (C(r)) aiming to apply C(r)derived statistics. For real-time application it is important to reduce calculation time. It is shown how our method works for EEG time series. Methods: To achieve online

  17. Feasibility of real-time calculation of correlation integral derived statistics applied to EEG time series

    NARCIS (Netherlands)

    Broek, P.L.C. van den; Egmond, J. van; Rijn, C.M. van; Takens, F.; Coenen, A.M.L.; Booij, L.H.D.J.

    2005-01-01

    This study assessed the feasibility of online calculation of the correlation integral (C(r)) aiming to apply C(r)-derived statistics. For real-time application it is important to reduce calculation time. It is shown how our method works for EEG time series. Methods: To achieve online calculation of

  18. Explicit Time Integrators for Nonlinear Dynamics Derived from the Midpoint Rule

    Directory of Open Access Journals (Sweden)

    P. Krysl

    2004-01-01

    Full Text Available We address the design of time integrators for mechanical systems that are explicit in the forcing evaluations. Our starting point is the midpoint rule, either in the classical form for the vector space setting, or in the Lie form for the rotation group. By introducing discrete, concentrated impulses we can approximate the forcing impressed upon the system over the time step, and thus arrive at first-order integrators. These can then be composed to yield a second order integrator with very desirable properties: symplecticity and momentum conservation. 

  19. Energy conservation in Newmark based time integration algorithms

    DEFF Research Database (Denmark)

    Krenk, Steen

    2006-01-01

    Energy balance equations are established for the Newmark time integration algorithm, and for the derived algorithms with algorithmic damping introduced via averaging, the so-called a-methods. The energy balance equations form a sequence applicable to: Newmark integration of the undamped equations...... of motion, an extended form including structural damping, and finally the generalized form including structural as well as algorithmic damping. In all three cases the expression for energy, appearing in the balance equation, is the mechanical energy plus some additional terms generated by the discretization...

  20. The imaginary-time path integral and non-time-reversal-invariant saddle points of the Euclidean action

    International Nuclear Information System (INIS)

    Dasgupta, I.

    1998-01-01

    We discuss new bounce-like (but non-time-reversal-invariant) solutions to Euclidean equations of motion, which we dub boomerons. In the Euclidean path integral approach to quantum theories, boomerons make an imaginary contribution to the vacuum energy. The fake vacuum instability can be removed by cancelling boomeron contributions against contributions from time reversed boomerons (anti-boomerons). The cancellation rests on a sign choice whose significance is not completely understood in the path integral method. (orig.)

  1. Discounting Models for Outcomes over Continuous Time

    DEFF Research Database (Denmark)

    Harvey, Charles M.; Østerdal, Lars Peter

    Events that occur over a period of time can be described either as sequences of outcomes at discrete times or as functions of outcomes in an interval of time. This paper presents discounting models for events of the latter type. Conditions on preferences are shown to be satisfied if and only if t...... if the preferences are represented by a function that is an integral of a discounting function times a scale defined on outcomes at instants of time....

  2. A grey-forecasting interval-parameter mixed-integer programming approach for integrated electric-environmental management–A case study of Beijing

    International Nuclear Information System (INIS)

    Wang, Xingwei; Cai, Yanpeng; Chen, Jiajun; Dai, Chao

    2013-01-01

    In this study, a GFIPMIP (grey-forecasting interval-parameter mixed-integer programming) approach was developed for supporting IEEM (integrated electric-environmental management) in Beijing. It was an attempt to incorporate an energy-forecasting model within a general modeling framework at the municipal level. The developed GFIPMIP model can not only forecast electric demands, but also reflect dynamic, interactive, and uncertain characteristics of the IEEM system in Beijing. Moreover, it can address issues regarding power supply, and emission reduction of atmospheric pollutants and GHG (greenhouse gas). Optimal solutions were obtained related to power generation patterns and facility capacity expansion schemes under a series of system constraints. Two scenarios were analyzed based on multiple environmental policies. The results were useful for helping decision makers identify desired management strategies to guarantee the city's power supply and mitigate emissions of GHG and atmospheric pollutants. The results also suggested that the developed GFIPMIP model be applicable to similar engineering problems. - Highlights: • A grey-forecasting interval-parameter mixed integer programming (GFIPMIP) approach was developed. • It could reflect dynamic, interactive, and uncertain characteristics of an IEEM system. • The developed GFIPMIP approach was used for supporting IEEM system planning in Beijing. • Two scenarios were established based on different environmental policies and management targets. • Optimal schemes for power generation, energy supply, and environmental protection were identified

  3. The use of a DNA stabilizer in human dental tissues stored under different temperature conditions and time intervals

    Science.gov (United States)

    TERADA, Andrea Sayuri Silveira Dias; da SILVA, Luiz Antonio Ferreira; GALO, Rodrigo; de AZEVEDO, Aline; GERLACH, Raquel Fernanda; da SILVA, Ricardo Henrique Alves

    2014-01-01

    Objective The present study evaluated the use of a reagent to stabilize the DNA extracted from human dental tissues stored under different temperature conditions and time intervals. Material and Methods A total of 161 teeth were divided into two distinct groups: intact teeth and isolated dental pulp tissue. The samples were stored with or without the product at different time intervals and temperature. After storage, DNA extraction and genomic DNA quantification were performed using real-time PCR; the fragments of the 32 samples that represented each possible condition were analyzed to find the four pre-selected markers in STR analysis. Results The results of the quantification showed values ranging from 0.01 to 10,246.88 ng/μL of DNA. The statistical difference in the quantity of DNA was observed when the factors related to the time and temperature of storage were analyzed. In relation to the use of the specific reagent, its use was relevant in the group of intact teeth when they were at room temperature for 30 and 180 days. The analysis of the fragments in the 32 selected samples was possible irrespective of the amount of DNA, confirming that the STR analysis using an automated method yields good results. Conclusions The use of a specific reagent showed a significant difference in stabilizing DNA in samples of intact human teeth stored at room temperature for 30 and 180 days, while the results showed no justification for using the product under the other conditions tested. PMID:25141206

  4. Rigorous time slicing approach to Feynman path integrals

    CERN Document Server

    Fujiwara, Daisuke

    2017-01-01

    This book proves that Feynman's original definition of the path integral actually converges to the fundamental solution of the Schrödinger equation at least in the short term if the potential is differentiable sufficiently many times and its derivatives of order equal to or higher than two are bounded. The semi-classical asymptotic formula up to the second term of the fundamental solution is also proved by a method different from that of Birkhoff. A bound of the remainder term is also proved. The Feynman path integral is a method of quantization using the Lagrangian function, whereas Schrödinger's quantization uses the Hamiltonian function. These two methods are believed to be equivalent. But equivalence is not fully proved mathematically, because, compared with Schrödinger's method, there is still much to be done concerning rigorous mathematical treatment of Feynman's method. Feynman himself defined a path integral as the limit of a sequence of integrals over finite-dimensional spaces which is obtained by...

  5. Method of high precision interval measurement in pulse laser ranging system

    Science.gov (United States)

    Wang, Zhen; Lv, Xin-yuan; Mao, Jin-jin; Liu, Wei; Yang, Dong

    2013-09-01

    Laser ranging is suitable for laser system, for it has the advantage of high measuring precision, fast measuring speed,no cooperative targets and strong resistance to electromagnetic interference,the measuremen of laser ranging is the key paremeters affecting the performance of the whole system.The precision of the pulsed laser ranging system was decided by the precision of the time interval measurement, the principle structure of laser ranging system was introduced, and a method of high precision time interval measurement in pulse laser ranging system was established in this paper.Based on the analysis of the factors which affected the precision of range measure,the pulse rising edges discriminator was adopted to produce timing mark for the start-stop time discrimination,and the TDC-GP2 high precision interval measurement system based on TMS320F2812 DSP was designed to improve the measurement precision.Experimental results indicate that the time interval measurement method in this paper can obtain higher range accuracy. Compared with the traditional time interval measurement system,the method simplifies the system design and reduce the influence of bad weather conditions,furthermore,it satisfies the requirements of low costs and miniaturization.

  6. New design for photonic temporal integration with combined high processing speed and long operation time window.

    Science.gov (United States)

    Asghari, Mohammad H; Park, Yongwoo; Azaña, José

    2011-01-17

    We propose and experimentally prove a novel design for implementing photonic temporal integrators simultaneously offering a high processing bandwidth and a long operation time window, namely a large time-bandwidth product. The proposed scheme is based on concatenating in series a time-limited ultrafast photonic temporal integrator, e.g. implemented using a fiber Bragg grating (FBG), with a discrete-time (bandwidth limited) optical integrator, e.g. implemented using an optical resonant cavity. This design combines the advantages of these two previously demonstrated photonic integrator solutions, providing a processing speed as high as that of the time-limited ultrafast integrator and an operation time window fixed by the discrete-time integrator. Proof-of-concept experiments are reported using a uniform fiber Bragg grating (as the original time-limited integrator) connected in series with a bulk-optics coherent interferometers' system (as a passive 4-points discrete-time photonic temporal integrator). Using this setup, we demonstrate accurate temporal integration of complex-field optical signals with time-features as fast as ~6 ps, only limited by the processing bandwidth of the FBG integrator, over time durations as long as ~200 ps, which represents a 4-fold improvement over the operation time window (~50 ps) of the original FBG integrator.

  7. An open-chain imaginary-time path-integral sampling approach to the calculation of approximate symmetrized quantum time correlation functions

    Science.gov (United States)

    Cendagorta, Joseph R.; Bačić, Zlatko; Tuckerman, Mark E.

    2018-03-01

    We introduce a scheme for approximating quantum time correlation functions numerically within the Feynman path integral formulation. Starting with the symmetrized version of the correlation function expressed as a discretized path integral, we introduce a change of integration variables often used in the derivation of trajectory-based semiclassical methods. In particular, we transform to sum and difference variables between forward and backward complex-time propagation paths. Once the transformation is performed, the potential energy is expanded in powers of the difference variables, which allows us to perform the integrals over these variables analytically. The manner in which this procedure is carried out results in an open-chain path integral (in the remaining sum variables) with a modified potential that is evaluated using imaginary-time path-integral sampling rather than requiring the generation of a large ensemble of trajectories. Consequently, any number of path integral sampling schemes can be employed to compute the remaining path integral, including Monte Carlo, path-integral molecular dynamics, or enhanced path-integral molecular dynamics. We believe that this approach constitutes a different perspective in semiclassical-type approximations to quantum time correlation functions. Importantly, we argue that our approximation can be systematically improved within a cumulant expansion formalism. We test this approximation on a set of one-dimensional problems that are commonly used to benchmark approximate quantum dynamical schemes. We show that the method is at least as accurate as the popular ring-polymer molecular dynamics technique and linearized semiclassical initial value representation for correlation functions of linear operators in most of these examples and improves the accuracy of correlation functions of nonlinear operators.

  8. An open-chain imaginary-time path-integral sampling approach to the calculation of approximate symmetrized quantum time correlation functions.

    Science.gov (United States)

    Cendagorta, Joseph R; Bačić, Zlatko; Tuckerman, Mark E

    2018-03-14

    We introduce a scheme for approximating quantum time correlation functions numerically within the Feynman path integral formulation. Starting with the symmetrized version of the correlation function expressed as a discretized path integral, we introduce a change of integration variables often used in the derivation of trajectory-based semiclassical methods. In particular, we transform to sum and difference variables between forward and backward complex-time propagation paths. Once the transformation is performed, the potential energy is expanded in powers of the difference variables, which allows us to perform the integrals over these variables analytically. The manner in which this procedure is carried out results in an open-chain path integral (in the remaining sum variables) with a modified potential that is evaluated using imaginary-time path-integral sampling rather than requiring the generation of a large ensemble of trajectories. Consequently, any number of path integral sampling schemes can be employed to compute the remaining path integral, including Monte Carlo, path-integral molecular dynamics, or enhanced path-integral molecular dynamics. We believe that this approach constitutes a different perspective in semiclassical-type approximations to quantum time correlation functions. Importantly, we argue that our approximation can be systematically improved within a cumulant expansion formalism. We test this approximation on a set of one-dimensional problems that are commonly used to benchmark approximate quantum dynamical schemes. We show that the method is at least as accurate as the popular ring-polymer molecular dynamics technique and linearized semiclassical initial value representation for correlation functions of linear operators in most of these examples and improves the accuracy of correlation functions of nonlinear operators.

  9. Convex Interval Games

    NARCIS (Netherlands)

    Alparslan-Gok, S.Z.; Brânzei, R.; Tijs, S.H.

    2008-01-01

    In this paper, convex interval games are introduced and some characterizations are given. Some economic situations leading to convex interval games are discussed. The Weber set and the Shapley value are defined for a suitable class of interval games and their relations with the interval core for

  10. Orientation, Evaluation, and Integration of Part-Time Nursing Faculty.

    Science.gov (United States)

    Carlson, Joanne S

    2015-07-10

    This study helps to quantify and describe orientation, evaluation, and integration practices pertaining to part-time clinical nursing faculty teaching in prelicensure nursing education programs. A researcher designed Web-based survey was used to collect information from a convenience sample of part-time clinical nursing faculty teaching in prelicensure nursing programs. Survey questions focused on the amount and type of orientation, evaluation, and integration practices. Descriptive statistics were used to analyze results. Respondents reported on average four hours of orientation, with close to half reporting no more than two hours. Evaluative feedback was received much more often from students than from full-time faculty. Most respondents reported receiving some degree of mentoring and that it was easy to get help from full-time faculty. Respondents reported being most informed about student evaluation procedures, grading, and the steps to take when students are not meeting course objectives, and less informed about changes to ongoing curriculum and policy.

  11. An energy-stable time-integrator for phase-field models

    KAUST Repository

    Vignal, Philippe

    2016-12-27

    We introduce a provably energy-stable time-integration method for general classes of phase-field models with polynomial potentials. We demonstrate how Taylor series expansions of the nonlinear terms present in the partial differential equations of these models can lead to expressions that guarantee energy-stability implicitly, which are second-order accurate in time. The spatial discretization relies on a mixed finite element formulation and isogeometric analysis. We also propose an adaptive time-stepping discretization that relies on a first-order backward approximation to give an error-estimator. This error estimator is accurate, robust, and does not require the computation of extra solutions to estimate the error. This methodology can be applied to any second-order accurate time-integration scheme. We present numerical examples in two and three spatial dimensions, which confirm the stability and robustness of the method. The implementation of the numerical schemes is done in PetIGA, a high-performance isogeometric analysis framework.

  12. An energy-stable time-integrator for phase-field models

    KAUST Repository

    Vignal, Philippe; Collier, N.; Dalcin, Lisandro; Brown, D.L.; Calo, V.M.

    2016-01-01

    We introduce a provably energy-stable time-integration method for general classes of phase-field models with polynomial potentials. We demonstrate how Taylor series expansions of the nonlinear terms present in the partial differential equations of these models can lead to expressions that guarantee energy-stability implicitly, which are second-order accurate in time. The spatial discretization relies on a mixed finite element formulation and isogeometric analysis. We also propose an adaptive time-stepping discretization that relies on a first-order backward approximation to give an error-estimator. This error estimator is accurate, robust, and does not require the computation of extra solutions to estimate the error. This methodology can be applied to any second-order accurate time-integration scheme. We present numerical examples in two and three spatial dimensions, which confirm the stability and robustness of the method. The implementation of the numerical schemes is done in PetIGA, a high-performance isogeometric analysis framework.

  13. Spectral of electrocardiographic RR intervals to indicate atrial fibrillation

    Science.gov (United States)

    Nuryani, Nuryani; Satrio Nugroho, Anto

    2017-11-01

    Atrial fibrillation is a serious heart diseases, which is associated on the risk of death, and thus an early detection of atrial fibrillation is necessary. We have investigated spectral pattern of electrocardiogram in relation to atrial fibrillation. The utilized feature of electrocardiogram is RR interval. RR interval is the time interval between a two-consecutive R peaks. A series of RR intervals in a time segment is converted to a signal with a frequency domain. The frequency components are investigated to find the components which significantly associate to atrial fibrillation. A segment is defined as atrial fibrillation or normal segments by considering a defined number of atrial fibrillation RR in the segment. Using clinical data of 23 patients with atrial fibrillation, we find that the frequency components could be used to indicate atrial fibrillation.

  14. A space-time mixed galerkin marching-on-in-time scheme for the time-domain combined field integral equation

    KAUST Repository

    Beghein, Yves

    2013-03-01

    The time domain combined field integral equation (TD-CFIE), which is constructed from a weighted sum of the time domain electric and magnetic field integral equations (TD-EFIE and TD-MFIE) for analyzing transient scattering from closed perfect electrically conducting bodies, is free from spurious resonances. The standard marching-on-in-time technique for discretizing the TD-CFIE uses Galerkin and collocation schemes in space and time, respectively. Unfortunately, the standard scheme is theoretically not well understood: stability and convergence have been proven for only one class of space-time Galerkin discretizations. Moreover, existing discretization schemes are nonconforming, i.e., the TD-MFIE contribution is tested with divergence conforming functions instead of curl conforming functions. We therefore introduce a novel space-time mixed Galerkin discretization for the TD-CFIE. A family of temporal basis and testing functions with arbitrary order is introduced. It is explained how the corresponding interactions can be computed efficiently by existing collocation-in-time codes. The spatial mixed discretization is made fully conforming and consistent by leveraging both Rao-Wilton-Glisson and Buffa-Christiansen basis functions and by applying the appropriate bi-orthogonalization procedures. The combination of both techniques is essential when high accuracy over a broad frequency band is required. © 2012 IEEE.

  15. Overconfidence in Interval Estimates

    Science.gov (United States)

    Soll, Jack B.; Klayman, Joshua

    2004-01-01

    Judges were asked to make numerical estimates (e.g., "In what year was the first flight of a hot air balloon?"). Judges provided high and low estimates such that they were X% sure that the correct answer lay between them. They exhibited substantial overconfidence: The correct answer fell inside their intervals much less than X% of the time. This…

  16. Nonlinear dynamic systems identification using recurrent interval type-2 TSK fuzzy neural network - A novel structure.

    Science.gov (United States)

    El-Nagar, Ahmad M

    2018-01-01

    In this study, a novel structure of a recurrent interval type-2 Takagi-Sugeno-Kang (TSK) fuzzy neural network (FNN) is introduced for nonlinear dynamic and time-varying systems identification. It combines the type-2 fuzzy sets (T2FSs) and a recurrent FNN to avoid the data uncertainties. The fuzzy firing strengths in the proposed structure are returned to the network input as internal variables. The interval type-2 fuzzy sets (IT2FSs) is used to describe the antecedent part for each rule while the consequent part is a TSK-type, which is a linear function of the internal variables and the external inputs with interval weights. All the type-2 fuzzy rules for the proposed RIT2TSKFNN are learned on-line based on structure and parameter learning, which are performed using the type-2 fuzzy clustering. The antecedent and consequent parameters of the proposed RIT2TSKFNN are updated based on the Lyapunov function to achieve network stability. The obtained results indicate that our proposed network has a small root mean square error (RMSE) and a small integral of square error (ISE) with a small number of rules and a small computation time compared with other type-2 FNNs. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  17. Detection of anatomical changes in lung cancer patients with 2D time-integrated, 2D time-resolved and 3D time-integrated portal dosimetry: a simulation study

    Science.gov (United States)

    Wolfs, Cecile J. A.; Brás, Mariana G.; Schyns, Lotte E. J. R.; Nijsten, Sebastiaan M. J. J. G.; van Elmpt, Wouter; Scheib, Stefan G.; Baltes, Christof; Podesta, Mark; Verhaegen, Frank

    2017-08-01

    The aim of this work is to assess the performance of 2D time-integrated (2D-TI), 2D time-resolved (2D-TR) and 3D time-integrated (3D-TI) portal dosimetry in detecting dose discrepancies between the planned and (simulated) delivered dose caused by simulated changes in the anatomy of lung cancer patients. For six lung cancer patients, tumor shift, tumor regression and pleural effusion are simulated by modifying their CT images. Based on the modified CT images, time-integrated (TI) and time-resolved (TR) portal dose images (PDIs) are simulated and 3D-TI doses are calculated. The modified and original PDIs and 3D doses are compared by a gamma analysis with various gamma criteria. Furthermore, the difference in the D 95% (ΔD 95%) of the GTV is calculated and used as a gold standard. The correlation between the gamma fail rate and the ΔD 95% is investigated, as well the sensitivity and specificity of all combinations of portal dosimetry method, gamma criteria and gamma fail rate threshold. On the individual patient level, there is a correlation between the gamma fail rate and the ΔD 95%, which cannot be found at the group level. The sensitivity and specificity analysis showed that there is not one combination of portal dosimetry method, gamma criteria and gamma fail rate threshold that can detect all simulated anatomical changes. This work shows that it will be more beneficial to relate portal dosimetry and DVH analysis on the patient level, rather than trying to quantify a relationship for a group of patients. With regards to optimizing sensitivity and specificity, different combinations of portal dosimetry method, gamma criteria and gamma fail rate should be used to optimally detect certain types of anatomical changes.

  18. Detection of anatomical changes in lung cancer patients with 2D time-integrated, 2D time-resolved and 3D time-integrated portal dosimetry: a simulation study.

    Science.gov (United States)

    Wolfs, Cecile J A; Brás, Mariana G; Schyns, Lotte E J R; Nijsten, Sebastiaan M J J G; van Elmpt, Wouter; Scheib, Stefan G; Baltes, Christof; Podesta, Mark; Verhaegen, Frank

    2017-07-12

    The aim of this work is to assess the performance of 2D time-integrated (2D-TI), 2D time-resolved (2D-TR) and 3D time-integrated (3D-TI) portal dosimetry in detecting dose discrepancies between the planned and (simulated) delivered dose caused by simulated changes in the anatomy of lung cancer patients. For six lung cancer patients, tumor shift, tumor regression and pleural effusion are simulated by modifying their CT images. Based on the modified CT images, time-integrated (TI) and time-resolved (TR) portal dose images (PDIs) are simulated and 3D-TI doses are calculated. The modified and original PDIs and 3D doses are compared by a gamma analysis with various gamma criteria. Furthermore, the difference in the D 95% (ΔD 95% ) of the GTV is calculated and used as a gold standard. The correlation between the gamma fail rate and the ΔD 95% is investigated, as well the sensitivity and specificity of all combinations of portal dosimetry method, gamma criteria and gamma fail rate threshold. On the individual patient level, there is a correlation between the gamma fail rate and the ΔD 95% , which cannot be found at the group level. The sensitivity and specificity analysis showed that there is not one combination of portal dosimetry method, gamma criteria and gamma fail rate threshold that can detect all simulated anatomical changes. This work shows that it will be more beneficial to relate portal dosimetry and DVH analysis on the patient level, rather than trying to quantify a relationship for a group of patients. With regards to optimizing sensitivity and specificity, different combinations of portal dosimetry method, gamma criteria and gamma fail rate should be used to optimally detect certain types of anatomical changes.

  19. Effect of time interval between capecitabine intake and radiotherapy on local recurrence-free survival in preoperative chemoradiation for locally advanced rectal cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yeon Joo; Kim, Jong Hoon; Yu, Chang Sik; Kim, Tae Won; Jang, Se Jin; Choi, Eun Kyung; Kim, Jin Cheon [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of); Choi, Won Sik [University of Ulsan College of Medicine, Gangneung (Korea, Republic of)

    2017-06-15

    The concentration of capecitabine peaks at 1–2 hours after administration. We therefore assumed that proper timing of capecitabine administration and radiotherapy would maximize radiosensitization and influence survival among patients with locally advanced rectal cancer. We retrospectively reviewed 223 patients with locally advanced rectal cancer who underwent preoperative chemoradiation, followed by surgery from January 2002 to May 2006. All patients underwent pelvic radiotherapy (50 Gy/25 fractions) and received capecitabine twice daily at 12-hour intervals (1,650 mg/m2/day). Patients were divided into two groups according to the time interval between capecitabine intake and radiotherapy. Patients who took capecitabine 1 hour before radiotherapy were classified as Group A (n = 109); all others were classified as Group B (n = 114). The median follow-up period was 72 months (range, 7 to 149 months). Although Group A had a significantly higher rate of good responses (44% vs. 25%; p = 0.005), the 5-year local recurrence-free survival rates of 93% in Group A and 97% in Group B did not differ significantly (p = 0.519). The 5-year disease-free survival and overall survival rates were also comparable between the groups. Despite the better pathological response in Group A, the time interval between capecitabine and radiotherapy administration did not have a significant effect on survivals. Further evaluations are needed to clarify the interaction of these treatment modalities.

  20. A parallel optimization method for product configuration and supplier selection based on interval

    Science.gov (United States)

    Zheng, Jian; Zhang, Meng; Li, Guoxi

    2017-06-01

    In the process of design and manufacturing, product configuration is an important way of product development, and supplier selection is an essential component of supply chain management. To reduce the risk of procurement and maximize the profits of enterprises, this study proposes to combine the product configuration and supplier selection, and express the multiple uncertainties as interval numbers. An integrated optimization model of interval product configuration and supplier selection was established, and NSGA-II was put forward to locate the Pareto-optimal solutions to the interval multiobjective optimization model.

  1. Using the Initial Systolic Time Interval to assess cardiac autonomic function in Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Jan H. Meijer

    2011-12-01

    Full Text Available The Initial Systolic Time Interval (ISTI has been defined as the time difference between the peak electrical and peak mechanical activity of the heart. ISTI is obtained from the electro-cardiogram and the impedance cardiogram. The response of ISTI while breathing at rest and to a deep breathing stimulus was studied in a group of patients suffering from Parkinson's disease (PD and a group of healthy control subjects. ISTI showed substantial variability during these manoeuvres. The tests showed that the variability of RR and ISTI was substantially different between PD patients and controls. It is hypothesized that in PD patients the sympathetic system compensates for the loss of regulatory control function of the blood-pressure by the parasympathetic system. It is concluded that ISTI is a practical, additional and independent parameter that can be used to assist other tests in evaluating autonomic control of the heart in PD patients.doi:10.5617/jeb.216 J Electr Bioimp, vol. 2, pp. 98-101, 2011

  2. Real-time hybrid simulation using the convolution integral method

    International Nuclear Information System (INIS)

    Kim, Sung Jig; Christenson, Richard E; Wojtkiewicz, Steven F; Johnson, Erik A

    2011-01-01

    This paper proposes a real-time hybrid simulation method that will allow complex systems to be tested within the hybrid test framework by employing the convolution integral (CI) method. The proposed CI method is potentially transformative for real-time hybrid simulation. The CI method can allow real-time hybrid simulation to be conducted regardless of the size and complexity of the numerical model and for numerical stability to be ensured in the presence of high frequency responses in the simulation. This paper presents the general theory behind the proposed CI method and provides experimental verification of the proposed method by comparing the CI method to the current integration time-stepping (ITS) method. Real-time hybrid simulation is conducted in the Advanced Hazard Mitigation Laboratory at the University of Connecticut. A seismically excited two-story shear frame building with a magneto-rheological (MR) fluid damper is selected as the test structure to experimentally validate the proposed method. The building structure is numerically modeled and simulated, while the MR damper is physically tested. Real-time hybrid simulation using the proposed CI method is shown to provide accurate results

  3. Restricted Interval Valued Neutrosophic Sets and Restricted Interval Valued Neutrosophic Topological Spaces

    Directory of Open Access Journals (Sweden)

    Anjan Mukherjee

    2016-08-01

    Full Text Available In this paper we introduce the concept of restricted interval valued neutrosophic sets (RIVNS in short. Some basic operations and properties of RIVNS are discussed. The concept of restricted interval valued neutrosophic topology is also introduced together with restricted interval valued neutrosophic finer and restricted interval valued neutrosophic coarser topology. We also define restricted interval valued neutrosophic interior and closer of a restricted interval valued neutrosophic set. Some theorems and examples are cites. Restricted interval valued neutrosophic subspace topology is also studied.

  4. A study on assessment methodology of surveillance test interval and Allowed Outage Time

    Energy Technology Data Exchange (ETDEWEB)

    Che, Moo Seong; Cheong, Chang Hyeon; Ryu, Yeong Woo; Cho, Jae Seon; Heo, Chang Wook; Kim, Do Hyeong; Kim, Joo Yeol; Kim, Yun Ik; Yang, Hei Chang [Seoul National Univ., Seoul (Korea, Republic of)

    1997-07-15

    Objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. In the second year of this study, the sensitivity analyses about the failure factors of the components are performed in the bases of the assessment methodologies of the first study, the interaction modeling of the STI and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code.

  5. A study on assessment methodology of surveillance test interval and Allowed Outage Time

    International Nuclear Information System (INIS)

    Che, Moo Seong; Cheong, Chang Hyeon; Ryu, Yeong Woo; Cho, Jae Seon; Heo, Chang Wook; Kim, Do Hyeong; Kim, Joo Yeol; Kim, Yun Ik; Yang, Hei Chang

    1997-07-01

    Objectives of this study is the development of methodology by which assesses the optimization of Surveillance Test Interval(STI) and Allowed Outage Time(AOT) using PSA method that can supplement the current deterministic methods and the improvement of Korean nuclear power plants safety. In the first year of this study, the survey about the assessment methodologies, modeling and results performed by domestic and international researches are performed as the basic step before developing the assessment methodology of this study. The assessment methodology that supplement the revealed problems in many other studies is presented and the application of new methodology into the example system assures the feasibility of this method. In the second year of this study, the sensitivity analyses about the failure factors of the components are performed in the bases of the assessment methodologies of the first study, the interaction modeling of the STI and AOT is quantified. And the reliability assessment methodology about the diesel generator is reviewed and applied to the PSA code

  6. Clinical and Biological Features of Interval Colorectal Cancer

    Directory of Open Access Journals (Sweden)

    Yu Mi Lee

    2017-05-01

    Full Text Available Interval colorectal cancer (I-CRC is defined as a CRC diagnosed within 60 months after a negative colonoscopy, taking into account that 5 years is the “mean sojourn time.” It is important to prevent the development of interval cancer. The development of interval colon cancer is associated with female sex, old age, family history of CRC, comorbidities, diverticulosis, and the skill of the endoscopist. During carcinogenesis, sessile serrated adenomas/polyps (SSA/Ps share many genomic and colonic site characteristics with I-CRCs. The clinical and biological features of I-CRC should be elucidated to prevent the development of interval colon cancer.

  7. Response-rate differences in variable-interval and variable-ratio schedules: An old problem revisited

    OpenAIRE

    Cole, Mark R.

    1994-01-01

    In Experiment 1, a variable-ratio 10 schedule became, successively, a variable-interval schedule with only the minimum interreinforcement intervals yoked to the variable ratio, or a variable-interval schedule with both interreinforcement intervals and reinforced interresponse times yoked to the variable ratio. Response rates in the variable-interval schedule with both interreinforcement interval and reinforced interresponse time yoking fell between the higher rates maintained by the variable-...

  8. Closeness-Centrality-Based Synchronization Criteria for Complex Dynamical Networks With Interval Time-Varying Coupling Delays.

    Science.gov (United States)

    Park, Myeongjin; Lee, Seung-Hoon; Kwon, Oh-Min; Seuret, Alexandre

    2017-09-06

    This paper investigates synchronization in complex dynamical networks (CDNs) with interval time-varying delays. The CDNs are representative of systems composed of a large number of interconnected dynamical units, and for the purpose of the mathematical analysis, the leading work is to model them as graphs whose nodes represent the dynamical units. At this time, we take note of the importance of each node in networks. One way, in this paper, is that the closeness-centrality mentioned in the field of social science is grafted onto the CDNs. By constructing a suitable Lyapunov-Krasovskii functional, and utilizing some mathematical techniques, the sufficient and closeness-centrality-based conditions for synchronization stability of the networks are established in terms of linear matrix inequalities. Ultimately, the use of the closeness-centrality can be weighted with regard to not only the interconnection relation among the nodes, which was utilized in the existing works but also more information about nodes. Here, the centrality will be added as the concerned information. Moreover, to avoid the computational burden causing the nonconvex term including the square of the time-varying delay, how to deal with it is applied by estimating it to the convex term including time-varying delay. Finally, two illustrative examples are given to show the advantage of the closeness-centrality in point of the robustness on time-delay.

  9. A point implicit time integration technique for slow transient flow problems

    Energy Technology Data Exchange (ETDEWEB)

    Kadioglu, Samet Y., E-mail: kadioglu@yildiz.edu.tr [Department of Mathematical Engineering, Yildiz Technical University, 34210 Davutpasa-Esenler, Istanbul (Turkey); Berry, Ray A., E-mail: ray.berry@inl.gov [Idaho National Laboratory, P.O. Box 1625, MS 3840, Idaho Falls, ID 83415 (United States); Martineau, Richard C. [Idaho National Laboratory, P.O. Box 1625, MS 3840, Idaho Falls, ID 83415 (United States)

    2015-05-15

    Highlights: • This new method does not require implicit iteration; instead it time advances the solutions in a similar spirit to explicit methods. • It is unconditionally stable, as a fully implicit method would be. • It exhibits the simplicity of implementation of an explicit method. • It is specifically designed for slow transient flow problems of long duration such as can occur inside nuclear reactor coolant systems. • Our findings indicate the new method can integrate slow transient problems very efficiently; and its implementation is very robust. - Abstract: We introduce a point implicit time integration technique for slow transient flow problems. The method treats the solution variables of interest (that can be located at cell centers, cell edges, or cell nodes) implicitly and the rest of the information related to same or other variables are handled explicitly. The method does not require implicit iteration; instead it time advances the solutions in a similar spirit to explicit methods, except it involves a few additional function(s) evaluation steps. Moreover, the method is unconditionally stable, as a fully implicit method would be. This new approach exhibits the simplicity of implementation of explicit methods and the stability of implicit methods. It is specifically designed for slow transient flow problems of long duration wherein one would like to perform time integrations with very large time steps. Because the method can be time inaccurate for fast transient problems, particularly with larger time steps, an appropriate solution strategy for a problem that evolves from a fast to a slow transient would be to integrate the fast transient with an explicit or semi-implicit technique and then switch to this point implicit method as soon as the time variation slows sufficiently. We have solved several test problems that result from scalar or systems of flow equations. Our findings indicate the new method can integrate slow transient problems very

  10. A point implicit time integration technique for slow transient flow problems

    International Nuclear Information System (INIS)

    Kadioglu, Samet Y.; Berry, Ray A.; Martineau, Richard C.

    2015-01-01

    Highlights: • This new method does not require implicit iteration; instead it time advances the solutions in a similar spirit to explicit methods. • It is unconditionally stable, as a fully implicit method would be. • It exhibits the simplicity of implementation of an explicit method. • It is specifically designed for slow transient flow problems of long duration such as can occur inside nuclear reactor coolant systems. • Our findings indicate the new method can integrate slow transient problems very efficiently; and its implementation is very robust. - Abstract: We introduce a point implicit time integration technique for slow transient flow problems. The method treats the solution variables of interest (that can be located at cell centers, cell edges, or cell nodes) implicitly and the rest of the information related to same or other variables are handled explicitly. The method does not require implicit iteration; instead it time advances the solutions in a similar spirit to explicit methods, except it involves a few additional function(s) evaluation steps. Moreover, the method is unconditionally stable, as a fully implicit method would be. This new approach exhibits the simplicity of implementation of explicit methods and the stability of implicit methods. It is specifically designed for slow transient flow problems of long duration wherein one would like to perform time integrations with very large time steps. Because the method can be time inaccurate for fast transient problems, particularly with larger time steps, an appropriate solution strategy for a problem that evolves from a fast to a slow transient would be to integrate the fast transient with an explicit or semi-implicit technique and then switch to this point implicit method as soon as the time variation slows sufficiently. We have solved several test problems that result from scalar or systems of flow equations. Our findings indicate the new method can integrate slow transient problems very

  11. RR-Interval variance of electrocardiogram for atrial fibrillation detection

    Science.gov (United States)

    Nuryani, N.; Solikhah, M.; Nugoho, A. S.; Afdala, A.; Anzihory, E.

    2016-11-01

    Atrial fibrillation is a serious heart problem originated from the upper chamber of the heart. The common indication of atrial fibrillation is irregularity of R peak-to-R-peak time interval, which is shortly called RR interval. The irregularity could be represented using variance or spread of RR interval. This article presents a system to detect atrial fibrillation using variances. Using clinical data of patients with atrial fibrillation attack, it is shown that the variance of electrocardiographic RR interval are higher during atrial fibrillation, compared to the normal one. Utilizing a simple detection technique and variances of RR intervals, we find a good performance of atrial fibrillation detection.

  12. Design of time-pulse coded optoelectronic neuronal elements for nonlinear transformation and integration

    Science.gov (United States)

    Krasilenko, Vladimir G.; Nikolsky, Alexander I.; Lazarev, Alexander A.; Lazareva, Maria V.

    2008-03-01

    In the paper the actuality of neurophysiologically motivated neuron arrays with flexibly programmable functions and operations with possibility to select required accuracy and type of nonlinear transformation and learning are shown. We consider neurons design and simulation results of multichannel spatio-time algebraic accumulation - integration of optical signals. Advantages for nonlinear transformation and summation - integration are shown. The offered circuits are simple and can have intellectual properties such as learning and adaptation. The integrator-neuron is based on CMOS current mirrors and comparators. The performance: consumable power - 100...500 μW, signal period- 0.1...1ms, input optical signals power - 0.2...20 μW time delays - less 1μs, the number of optical signals - 2...10, integration time - 10...100 of signal periods, accuracy or integration error - about 1%. Various modifications of the neuron-integrators with improved performance and for different applications are considered in the paper.

  13. MK-801 and memantine act differently on short-term memory tested with different time-intervals in the Morris water maze test.

    Science.gov (United States)

    Duda, Weronika; Wesierska, Malgorzata; Ostaszewski, Pawel; Vales, Karel; Nekovarova, Tereza; Stuchlik, Ales

    2016-09-15

    N-methyl-d-aspartate receptors (NMDARs) play a crucial role in spatial memory formation. In neuropharmacological studies their functioning strongly depends on testing conditions and the dosage of NMDAR antagonists. The aim of this study was to assess the immediate effects of NMDAR block by (+)MK-801 or memantine on short-term allothetic memory. Memory was tested in a working memory version of the Morris water maze test. In our version of the test, rats underwent one day of training with 8 trials, and then three experimental days when rats were injected intraperitoneally with low- 5 (MeL), high - 20 (MeH) mg/kg memantine, 0.1mg/kg MK-801 or 1ml/kg saline (SAL) 30min before testing, for three consecutive days. On each experimental day there was just one acquisition and one test trial, with an inter-trial interval of 5 or 15min. During training the hidden platform was relocated after each trial and during the experiment after each day. The follow-up effect was assessed on day 9. Intact rats improved their spatial memory across the one training day. With a 5min interval MeH rats had longer latency then all rats during retrieval. With a 15min interval the MeH rats presented worse working memory measured as retrieval minus acquisition trial for path than SAL and MeL and for latency than MeL rats. MK-801 rats had longer latency than SAL during retrieval. Thus, the high dose of memantine, contrary to low dose of MK-801 disrupts short-term memory independent on the time interval between acquisition and retrieval. This shows that short-term memory tested in a working memory version of water maze is sensitive to several parameters: i.e., NMDA receptor antagonist type, dosage and the time interval between learning and testing. Copyright © 2016. Published by Elsevier B.V.

  14. Time series analysis of the developed financial markets' integration using visibility graphs

    Science.gov (United States)

    Zhuang, Enyu; Small, Michael; Feng, Gang

    2014-09-01

    A time series representing the developed financial markets' segmentation from 1973 to 2012 is studied. The time series reveals an obvious market integration trend. To further uncover the features of this time series, we divide it into seven windows and generate seven visibility graphs. The measuring capabilities of the visibility graphs provide means to quantitatively analyze the original time series. It is found that the important historical incidents that influenced market integration coincide with variations in the measured graphical node degree. Through the measure of neighborhood span, the frequencies of the historical incidents are disclosed. Moreover, it is also found that large "cycles" and significant noise in the time series are linked to large and small communities in the generated visibility graphs. For large cycles, how historical incidents significantly affected market integration is distinguished by density and compactness of the corresponding communities.

  15. General new time formalism in the path integral

    International Nuclear Information System (INIS)

    Pak, N.K.; Sokmen, I.

    1983-08-01

    We describe a general method of applying point canonical transformations to the path integral followed by the corresponding new time transformations aimed at reducing an arbitrary one-dimensional problem into an exactly solvable form. Our result is independent of operator ordering ambiguities by construction. (author)

  16. Optimization of Spacecraft Rendezvous and Docking using Interval Analysis

    NARCIS (Netherlands)

    Van Kampen, E.; Chu, Q.P.; Mulder, J.A.

    2010-01-01

    This paper applies interval optimization to the fixed-time multiple impulse rendezvous and docking problem. Current methods for solving this type of optimization problem include for example genetic algorithms and gradient based optimization. Unlike these methods, interval methods can guarantee that

  17. The in vitro antibacterial effect of iodine-potassium iodide and calcium hydroxide in infected dentinal tubules at different time intervals.

    Science.gov (United States)

    Lin, Shaul; Kfir, Anda; Laviv, Amir; Sela, Galit; Fuss, Zvi

    2009-03-01

    The aim of this study was to evaluate the antibacterial effect of iodine-potassium iodide (IKI) and calcium hydroxide (CH) on dentinal tubules infected with Enterococcus faecalis (E. faecalis) at different time intervals. Hollow cylinders of bovine root dentin (n=45) were infected and divided into three equal groups filled with either IKI or CH and a positive control. After placing each medicament in the infected cylinders for time periods of 10 minutes, 48 hours and 7 days, microbiological samples were analyzed. At the end of each period, four 100 microm thick inner dentin layers (400 microm thick from each specimen) were removed using dental burs of increasing diameters. Dentin powder was cultured on agar plates to quantitatively assess their infection, expressed in colony forming units (cfu). In all layers of the positive control group, heavy bacterial infection was observed. After 10 minutes, IKI reduced the amount of viable bacteria more efficiently than CH, whereas at later time intervals CH showed the best results. For short periods of exposure, IKI has a more efficient antibacterial effect in the dentinal tubules than CH but CH performs better after longer durations of exposure. This research indicates the use of IKI is a better choice for disinfecting the root canal than CH if only a short duration of exposure is used because of its more efficient antibacterial effect. However, if a longer exposure time is used, then CH is a better choice because of its better disinfecting effect over time.

  18. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    NARCIS (Netherlands)

    de Jong, F.C.J.M.; de Roon, F.A.

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value

  19. Persistent fluctuations in stride intervals under fractal auditory stimulation.

    Science.gov (United States)

    Marmelat, Vivien; Torre, Kjerstin; Beek, Peter J; Daffertshofer, Andreas

    2014-01-01

    Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.

  20. Muscle Adaptations Following Short-Duration Bed Rest with Integrated Resistance, Interval, and Aerobic Exercise

    Science.gov (United States)

    Hackney, Kyle J.; Scott, Jessica M.; Buxton, Roxanne; Redd-Goetchius, Elizabeth; Crowell, J. Brent; Everett, Meghan E.; Wickwire, Jason; Ryder, Jeffrey W.; Bloomberg, Jacob J.; Ploutz-Snyder, Lori L.

    2011-01-01

    Unloading of the musculoskeletal system during space flight results in deconditioning that may impair mission-related task performance in astronauts. Exercise countermeasures have been frequently tested during bed rest (BR) and limb suspension; however, high-intensity, short-duration exercise prescriptions have not been fully explored. PURPOSE: To determine if a high intensity resistance, interval, and aerobic exercise program could protect against muscle atrophy and dysfunction when performed during short duration BR. METHODS: Nine subjects (1 female, 8 male) performed a combination of supine exercises during 2 weeks of horizontal BR. Resistance exercise (3 d / wk) consisted of squat, leg press, hamstring curl, and heel raise exercises (3 sets, 12 repetitions). Aerobic (6 d / wk) sessions alternated continuous (75% VO2 peak) and interval exercise (30 s, 2 min, and 4 min) and were completed on a supine cycle ergometer and vertical treadmill, respectively. Muscle volumes of the upper leg were calculated pre, mid, and post-BR using magnetic resonance imaging. Maximal isometric force (MIF), rate of force development (RFD), and peak power of the lower body extensors were measured twice before BR (averaged to represent pre) and once post BR. ANOVA with repeated measures and a priori planned contrasts were used to test for differences. RESULTS: There were no changes to quadriceps, hamstring, and adductor muscle volumes at mid and post BR time points compared to pre BR (Table 1). Peak power increased significantly from 1614 +/- 372 W to 1739 +/- 359 W post BR (+7.7%, p = 0.035). Neither MIF (pre: 1676 +/- 320 N vs. post: 1711 +/- 250 N, +2.1%, p = 0.333) nor RFD (pre: 7534 +/- 1265 N/ms vs. post: 6951 +/- 1241 N/ms, -7.7%, p = 0.136) were significantly impaired post BR.

  1. Distributed finite-time containment control for double-integrator multiagent systems.

    Science.gov (United States)

    Wang, Xiangyu; Li, Shihua; Shi, Peng

    2014-09-01

    In this paper, the distributed finite-time containment control problem for double-integrator multiagent systems with multiple leaders and external disturbances is discussed. In the presence of multiple dynamic leaders, by utilizing the homogeneous control technique, a distributed finite-time observer is developed for the followers to estimate the weighted average of the leaders' velocities at first. Then, based on the estimates and the generalized adding a power integrator approach, distributed finite-time containment control algorithms are designed to guarantee that the states of the followers converge to the dynamic convex hull spanned by those of the leaders in finite time. Moreover, as a special case of multiple dynamic leaders with zero velocities, the proposed containment control algorithms also work for the case of multiple stationary leaders without using the distributed observer. Simulations demonstrate the effectiveness of the proposed control algorithms.

  2. Integrated optical delay lines for time-division multiplexers

    NARCIS (Netherlands)

    Stopinski, S.T.; Malinowski, M.; Piramidowicz, R.; Kleijn, E.; Smit, M.K.; Leijtens, X.J.M.

    2013-01-01

    In this paper, we present a study of integrated optical delay lines (DLs) for application in optical time-division multiplexers. The investigated DLs are formed by spirally folded waveguides. The components were designed in a generic approach and fabricated in multi-project wafer runs on an

  3. Non-integrability of time-dependent spherically symmetric Yang-Mills equations

    International Nuclear Information System (INIS)

    Matinyan, S.G.; Prokhorenko, E.V.; Savvidy, G.K.

    1986-01-01

    The integrability of time-dependent spherically symmetric Yang-Mills equations is studied using the Fermi-Pasta-Ulam method. The phase space of this system is shown to have no quasi-periodic motion specific for integrable systems. In particular, the well-known Wu-Yang static solution is unstable, so its vicinity in phase is the stochasticity region

  4. Optimal time interval between capecitabine intake and radiotherapy in preoperative chemoradiation for locally advanced rectal cancer

    International Nuclear Information System (INIS)

    Yu, Chang Sik; Kim, Tae Won; Kim, Jong Hoon; Choi, Won Sik; Kim, Hee Cheol; Chang, Heung Moon; Ryu, Min Hee; Jang, Se Jin; Ahn, Seung Do; Lee, Sang-wook; Shin, Seong Soo; Choi, Eun Kyung; Kim, Jin Cheon

    2007-01-01

    Purpose: Capecitabine and its metabolites reach peak plasma concentrations 1 to 2 hours after a single oral administration, and concentrations rapidly decrease thereafter. We performed a retrospective analysis to find the optimal time interval between capecitabine administration and radiotherapy for rectal cancer. Methods and Materials: The time interval between capecitabine intake and radiotherapy was measured in patients who were treated with preoperative radiotherapy and concurrent capecitabine for rectal cancer. Patients were classified into the following groups. Group A1 included patients who took capecitabine 1 hour before radiotherapy, and Group B1 included all other patients. Group B1 was then subdivided into Group A2 (patients who took capecitabine 2 hours before radiotherapy) and Group B2. Group B2 was further divided into Group A3 and Group B3 with the same method. Total mesorectal excision was performed 6 weeks after completion of chemoradiation and the pathologic response was evaluated. Results: A total of 200 patients were enrolled in this study. Pathologic examination showed that Group A1 had higher rates of complete regression of primary tumors in the rectum (23.5% vs. 9.6%, p = 0.01), good response (44.7% vs. 25.2%, p = 0.006), and lower T stages (p = 0.021) compared with Group B1; however, Groups A2 and A3 did not show any improvement compared with Groups B2 and B3. Multivariate analysis showed that increases in primary tumors in the rectum and good response were only significant when capecitabine was administered 1 hour before radiotherapy. Conclusion: In preoperative chemoradiotherapy for rectal cancer, the pathologic response could be improved by administering capecitabine 1 hour before radiotherapy

  5. Integration and timing of basic and clinical sciences education.

    Science.gov (United States)

    Bandiera, Glen; Boucher, Andree; Neville, Alan; Kuper, Ayelet; Hodges, Brian

    2013-05-01

    Medical education has traditionally been compartmentalized into basic and clinical sciences, with the latter being viewed as the skillful application of the former. Over time, the relevance of basic sciences has become defined by their role in supporting clinical problem solving rather than being, of themselves, a defining knowledge base of physicians. As part of the national Future of Medical Education in Canada (FMEC MD) project, a comprehensive empirical environmental scan identified the timing and integration of basic sciences as a key pressing issue for medical education. Using the literature review, key informant interviews, stakeholder meetings, and subsequent consultation forums from the FMEC project, this paper details the empirical basis for focusing on the role of basic science, the evidentiary foundations for current practices, and the implications for medical education. Despite a dearth of definitive relevant studies, opinions about how best to integrate the sciences remain strong. Resource allocation, political power, educational philosophy, and the shift from a knowledge-based to a problem-solving profession all influence the debate. There was little disagreement that both sciences are important, that many traditional models emphasized deep understanding of limited basic science disciplines at the expense of other relevant content such as social sciences, or that teaching the sciences contemporaneously rather than sequentially has theoretical and practical merit. Innovations in integrated curriculum design have occurred internationally. Less clear are the appropriate balance of the sciences, the best integration model, and solutions to the political and practical challenges of integrated curricula. New curricula tend to emphasize integration, development of more diverse physician competencies, and preparation of physicians to adapt to evolving technology and patients' expectations. Refocusing the basic/clinical dichotomy to a foundational

  6. New four-dimensional integrals by Mellin-Barnes transform

    International Nuclear Information System (INIS)

    Allendes, Pedro; Guerrero, Natanael; Kondrashuk, Igor; Notte Cuello, Eduardo A.

    2010-01-01

    This paper is devoted to the calculation of a special class of integrals by Mellin-Barnes transform. It contains double integrals in the position space in d=4-2ε dimensions, where ε is parameter of dimensional regularization. These integrals contribute to the effective action of the N=4 supersymmetric Yang-Mills theory. The integrand is a fraction in which the numerator is the logarithm of the ratio of space-time intervals, and the denominator is the product of powers of space-time intervals. According to the method developed in the previous papers, in order to make use of the uniqueness technique for one of two integrations, we shift exponents in powers in the denominator of integrands by some multiples of ε. As the next step, the second integration in the position space is done by Mellin-Barnes transform. For normalizing procedure, we reproduce first the known result obtained earlier by Gegenbauer polynomial technique. Then, we make another shift of exponents in powers in the denominator to create the logarithm in the numerator as the derivative with respect to the shift parameter δ. We show that the technique of work with the contour of the integral modified in this way by using Mellin-Barnes transform repeats the technique of work with the contour of the integral without such a modification. In particular, all the operations with a shift of contour of integration over complex variables of twofold Mellin-Barnes transform are the same as before the δ modification of indices, and even the poles of residues coincide. This confirms the observation made in the previous papers that in the position space all the Green's function of N=4 supersymmetric Yang-Mills theory can be expressed in terms of Usyukina-Davydychev functions.

  7. QT interval correction for drug-induced changes in body temperature during integrated cardiovascular safety assessment in regulatory toxicology studies in dogs: A case study.

    Science.gov (United States)

    El Amrani, Abdel-Ilah; El Amrani-Callens, Francine; Loriot, Stéphane; Singh, Pramila; Forster, Roy

    2016-01-01

    Cardiovascular safety assessment requires accurate evaluation of QT interval, which depends on the length of the cardiac cycle and also on core body temperature (BT). Increases in QT interval duration have been shown to be associated with decreases in BT in dogs. An example of altered QT interval duration associated with changes in body temperature observed during a 4-week regulatory toxicology study in dogs is presented. Four groups of Beagle dogs received the vehicle or test item once on Day 1, followed by a 4-week observation period. Electrocardiogram (ECG) parameters were continuously recorded on Days 1 and 26 by jacketed external telemetry (JET). Core body temperature (BT) was measured with a conventional rectal thermometer at appropriate time-points during the Day 1 recording period. Decreased BT was observed approximately 2h after treatment on Day 1, along with increased QT interval duration corrected according to the Van de Water formula (QTcV), but the effect was no longer observed after correction for changes in BT [QTcVcT=QTcV-14(37.5-BT)] according to the Van der Linde formula. No significant changes in QTcV were reported at the end of the observation period, on Day 26. The present study demonstrates that core body (rectal) temperature can easily be monitored at appropriate time-points during JET recording in regulatory toxicology studies in dogs, in order to correct QT interval duration values for treatment-related changes in BT. The successful application of the Van der Linde formula to correct QTc prolongation for changes in BT was demonstrated. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  8. A Digitally Programmable Differential Integrator with Enlarged Time Constant

    Directory of Open Access Journals (Sweden)

    S. K. Debroy

    1994-12-01

    Full Text Available A new Operational Amplifier (OA-RC integrator network is described. The novelties of the design are used of single grounded capacitor, ideal integration function realization with dual-input capability and design flexibility for extremely large time constant involving an enlargement factor (K using product of resistor ratios. The aspect of the digital control of K through a programmable resistor array (PRA controlled by a microprocessor has also been implemented. The effect of the OA-poles has been analyzed which indicates degradation of the integrator-Q at higher frequencies. An appropriate Q-compensation design scheme exhibiting 1 : |A|2 order of Q-improvement has been proposed with supporting experimental observations.

  9. The incidence and clinical associated factors of interval colorectal cancers in Southern Taiwan

    Directory of Open Access Journals (Sweden)

    Cheng-En Tsai

    2018-03-01

    Conclusion: The prevalence of interval CRC in the present study is 3.28%. Comorbidity with ESRD and shorter ascending colon withdrawal time could be factors associated with interval CRC. Good colon preparation for the patients with ESRD and more ascending colon withdrawal time could reduce the interval CRC.

  10. Foster home integration as a temporal indicator of relational well-being.

    Science.gov (United States)

    Waid, Jeffrey; Kothari, Brianne H; McBeath, Bowen M; Bank, Lew

    2017-12-01

    This study sought to identify factors that contribute to the relational well-being of youth in substitute care. Using data from the [BLIND] study, youth responded to a 9-item measure of positive home integration, a scale designed to assess the relational experiences of youth to their caregivers and their integration into the foster home. Data were collected from youth in six month intervals, for an 18-month period of time. Latent growth curve modeling procedures were employed to determine if child, family, and case characteristics influenced youth's home integration trajectories. Results suggest stability in youth reports of home integration over time; however, children who were older at the time of study enrollment and youth who experienced placement changes during the period of observation experienced decreased home integration during the 18-month period. Results suggest youth's perspectives of home integration may in part be a function of the child's developmental stage and their experiences with foster care placement instability. Implications for practice and future research are discussed.

  11. Integrated vendor-buyer inventory models with inflation and time value of money in controllable lead time

    Directory of Open Access Journals (Sweden)

    Prashant Jindal

    2016-01-01

    Full Text Available In the global critical economic scenario, inflation plays a vital role in deciding optimal pricing of goods in any business entity. This article presents two single-vendor single-buyer integrated supply chain inventory models with inflation and time value of money. Shortage is allowed during the lead-time and it is partially backlogged. Lead time is controllable and can be reduced using crashing cost. In the first model, we consider the demand of lead time follows a normal distribution, and in the second model, it is considered distribution-free. For both cases, our objective is to minimize the integrated system cost by simultaneously optimizing the order quantity, safety factor, lead time and number of lots. The discounted cash flow and classical optimization technique are used to derive the optimal solution for both cases. Numerical examples including the sensitivity analysis of system parameters is provided to validate the results of the supply chain models.

  12. Distortion of time interval reproduction in an epileptic patient with a focal lesion in the right anterior insular/inferior frontal cortices.

    Science.gov (United States)

    Monfort, Vincent; Pfeuty, Micha; Klein, Madelyne; Collé, Steffie; Brissart, Hélène; Jonas, Jacques; Maillard, Louis

    2014-11-01

    This case report on an epileptic patient suffering from a focal lesion at the junction of the right anterior insular cortex (AIC) and the adjacent inferior frontal cortex (IFC) provides the first evidence that damage to this brain region impairs temporal performance in a visual time reproduction task in which participants had to reproduce the presentation duration (3, 5 and 7s) of emotionally-neutral and -negative pictures. Strikingly, as compared to a group of healthy subjects, the AIC/IFC case considerably overestimated reproduction times despite normal variability. The effect was obtained in all duration and emotion conditions. Such a distortion in time reproduction was not observed in four other epileptic patients without insular or inferior frontal damage. Importantly, the absolute extent of temporal over-reproduction increased in proportion to the magnitude of the target durations, which concurs with the scalar property of interval timing, and points to an impairment of time-specific rather than of non temporal (such as motor) mechanisms. Our data suggest that the disability in temporal reproduction of the AIC/IFC case would result from a distorted memory representation of the encoded duration, occurring during the process of storage and/or of recovery from memory and leading to a deviation of the temporal judgment during the reproduction task. These findings support the recent proposal that the anterior insular/inferior frontal cortices would be involved in time interval representation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. FLRW cosmology in Weyl-integrable space-time

    Energy Technology Data Exchange (ETDEWEB)

    Gannouji, Radouane [Department of Physics, Faculty of Science, Tokyo University of Science, 1–3, Kagurazaka, Shinjuku-ku, Tokyo 162-8601 (Japan); Nandan, Hemwati [Department of Physics, Gurukula Kangri Vishwavidayalaya, Haridwar 249404 (India); Dadhich, Naresh, E-mail: gannouji@rs.kagu.tus.ac.jp, E-mail: hntheory@yahoo.co.in, E-mail: nkd@iucaa.ernet.in [IUCAA, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

    2011-11-01

    We investigate the Weyl space-time extension of general relativity (GR) for studying the FLRW cosmology through focusing and defocusing of the geodesic congruences. We have derived the equations of evolution for expansion, shear and rotation in the Weyl space-time. In particular, we consider the Starobinsky modification, f(R) = R+βR{sup 2}−2Λ, of gravity in the Einstein-Palatini formalism, which turns out to reduce to the Weyl integrable space-time (WIST) with the Weyl vector being a gradient. The modified Raychaudhuri equation takes the form of the Hill-type equation which is then analysed to study the formation of the caustics. In this model, it is possible to have a Big Bang singularity free cyclic Universe but unfortunately the periodicity turns out to be extremely short.

  14. A general theory of intertemporal decision-making and the perception of time.

    Science.gov (United States)

    Namboodiri, Vijay M K; Mihalas, Stefan; Marton, Tanya M; Hussain Shuler, Marshall G

    2014-01-01

    Animals and humans make decisions based on their expected outcomes. Since relevant outcomes are often delayed, perceiving delays and choosing between earlier vs. later rewards (intertemporal decision-making) is an essential component of animal behavior. The myriad observations made in experiments studying intertemporal decision-making and time perception have not yet been rationalized within a single theory. Here we present a theory-Training-Integrated Maximized Estimation of Reinforcement Rate (TIMERR)-that explains a wide variety of behavioral observations made in intertemporal decision-making and the perception of time. Our theory postulates that animals make intertemporal choices to optimize expected reward rates over a limited temporal window which includes a past integration interval-over which experienced reward rate is estimated-as well as the expected delay to future reward. Using this theory, we derive mathematical expressions for both the subjective value of a delayed reward and the subjective representation of the delay. A unique contribution of our work is in finding that the past integration interval directly determines the steepness of temporal discounting and the non-linearity of time perception. In so doing, our theory provides a single framework to understand both intertemporal decision-making and time perception.

  15. National Ignition Facility sub-system design requirements integrated timing system SSDR 1.5.3

    International Nuclear Information System (INIS)

    Wiedwald, J.; Van Aersau, P.; Bliss, E.

    1996-01-01

    This System Design Requirement document establishes the performance, design, development, and test requirements for the Integrated Timing System, WBS 1.5.3 which is part of the NIF Integrated Computer Control System (ICCS). The Integrated Timing System provides all temporally-critical hardware triggers to components and equipment in other NIF systems

  16. A revised method to calculate the concentration time integral of atmospheric pollutants

    International Nuclear Information System (INIS)

    Voelz, E.; Schultz, H.

    1980-01-01

    It is possible to calculate the spreading of a plume in the atmosphere under nonstationary and nonhomogeneous conditions by introducing the ''particle-in-cell'' method (PIC). This is a numerical method by which the transport of and the diffusion in the plume is reproduced in such a way, that particles representing the concentration are moved time step-wise in restricted regions (cells) and separately with the advection velocity and the diffusion velocity. This has a systematical advantage over the steady state Gaussian plume model usually used. The fixed-point concentration time integral is calculated directly instead of being substituted by the locally integrated concentration at a constant time as is done in the Gaussian model. In this way inaccuracies due to the above mentioned computational techniques may be avoided for short-time emissions, as may be seen by the fact that both integrals do not lead to the same results. Also the PIC method enables one to consider the height-dependent wind speed and its variations while the Gaussian model can be used only with averaged wind data. The concentration time integral calculated by the PIC method results in higher maximum values in shorter distances to the source. This is an effect often observed in measurements. (author)

  17. Programming with Intervals

    Science.gov (United States)

    Matsakis, Nicholas D.; Gross, Thomas R.

    Intervals are a new, higher-level primitive for parallel programming with which programmers directly construct the program schedule. Programs using intervals can be statically analyzed to ensure that they do not deadlock or contain data races. In this paper, we demonstrate the flexibility of intervals by showing how to use them to emulate common parallel control-flow constructs like barriers and signals, as well as higher-level patterns such as bounded-buffer producer-consumer. We have implemented intervals as a publicly available library for Java and Scala.

  18. Persistent fluctuations in stride intervals under fractal auditory stimulation.

    Directory of Open Access Journals (Sweden)

    Vivien Marmelat

    Full Text Available Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.

  19. Simultaneous determination of radionuclides separable into natural decay series by use of time-interval analysis

    International Nuclear Information System (INIS)

    Hashimoto, Tetsuo; Sanada, Yukihisa; Uezu, Yasuhiro

    2004-01-01

    A delayed coincidence method, time-interval analysis (TIA), has been applied to successive α-α decay events on the millisecond time-scale. Such decay events are part of the 220 Rn→ 216 Po (T 1/2 145 ms) (Th-series) and 219 Rn→ 215 Po (T 1/2 1.78 ms) (Ac-series). By using TIA in addition to measurement of 226 Ra (U-series) from α-spectrometry by liquid scintillation counting (LSC), two natural decay series could be identified and separated. The TIA detection efficiency was improved by using the pulse-shape discrimination technique (PSD) to reject β-pulses, by solvent extraction of Ra combined with simple chemical separation, and by purging the scintillation solution with dry N 2 gas. The U- and Th-series together with the Ac-series were determined, respectively, from alpha spectra and TIA carried out immediately after Ra-extraction. Using the 221 Fr→ 217 At (T 1/2 32.3 ms) decay process as a tracer, overall yields were estimated from application of TIA to the 225 Ra (Np-decay series) at the time of maximum growth. The present method has proven useful for simultaneous determination of three radioactive decay series in environmental samples. (orig.)

  20. Timing of Formal Phase Safety Reviews for Large-Scale Integrated Hazard Analysis

    Science.gov (United States)

    Massie, Michael J.; Morris, A. Terry

    2010-01-01

    Integrated hazard analysis (IHA) is a process used to identify and control unacceptable risk. As such, it does not occur in a vacuum. IHA approaches must be tailored to fit the system being analyzed. Physical, resource, organizational and temporal constraints on large-scale integrated systems impose additional direct or derived requirements on the IHA. The timing and interaction between engineering and safety organizations can provide either benefits or hindrances to the overall end product. The traditional approach for formal phase safety review timing and content, which generally works well for small- to moderate-scale systems, does not work well for very large-scale integrated systems. This paper proposes a modified approach to timing and content of formal phase safety reviews for IHA. Details of the tailoring process for IHA will describe how to avoid temporary disconnects in major milestone reviews and how to maintain a cohesive end-to-end integration story particularly for systems where the integrator inherently has little to no insight into lower level systems. The proposal has the advantage of allowing the hazard analysis development process to occur as technical data normally matures.

  1. Leaky Integrate-and-Fire Neuron Circuit Based on Floating-Gate Integrator

    Science.gov (United States)

    Kornijcuk, Vladimir; Lim, Hyungkwang; Seok, Jun Yeong; Kim, Guhyun; Kim, Seong Keun; Kim, Inho; Choi, Byung Joon; Jeong, Doo Seok

    2016-01-01

    The artificial spiking neural network (SNN) is promising and has been brought to the notice of the theoretical neuroscience and neuromorphic engineering research communities. In this light, we propose a new type of artificial spiking neuron based on leaky integrate-and-fire (LIF) behavior. A distinctive feature of the proposed FG-LIF neuron is the use of a floating-gate (FG) integrator rather than a capacitor-based one. The relaxation time of the charge on the FG relies mainly on the tunnel barrier profile, e.g., barrier height and thickness (rather than the area). This opens up the possibility of large-scale integration of neurons. The circuit simulation results offered biologically plausible spiking activity (circuit was subject to possible types of noise, e.g., thermal noise and burst noise. The simulation results indicated remarkable distributional features of interspike intervals that are fitted to Gamma distribution functions, similar to biological neurons in the neocortex. PMID:27242416

  2. Efficient Simulation of Compressible, Viscous Fluids using Multi-rate Time Integration

    Science.gov (United States)

    Mikida, Cory; Kloeckner, Andreas; Bodony, Daniel

    2017-11-01

    In the numerical simulation of problems of compressible, viscous fluids with single-rate time integrators, the global timestep used is limited to that of the finest mesh point or fastest physical process. This talk discusses the application of multi-rate Adams-Bashforth (MRAB) integrators to an overset mesh framework to solve compressible viscous fluid problems of varying scale with improved efficiency, with emphasis on the strategy of timescale separation and the application of the resulting numerical method to two sample problems: subsonic viscous flow over a cylinder and a viscous jet in crossflow. The results presented indicate the numerical efficacy of MRAB integrators, outline a number of outstanding code challenges, demonstrate the expected reduction in time enabled by MRAB, and emphasize the need for proper load balancing through spatial decomposition in order for parallel runs to achieve the predicted time-saving benefit. This material is based in part upon work supported by the Department of Energy, National Nuclear Security Administration, under Award Number DE-NA0002374.

  3. The Interval Slope Method for Long-Term Forecasting of Stock Price Trends

    Directory of Open Access Journals (Sweden)

    Chun-xue Nie

    2016-01-01

    Full Text Available A stock price is a typical but complex type of time series data. We used the effective prediction of long-term time series data to schedule an investment strategy and obtain higher profit. Due to economic, environmental, and other factors, it is very difficult to obtain a precise long-term stock price prediction. The exponentially segmented pattern (ESP is introduced here and used to predict the fluctuation of different stock data over five future prediction intervals. The new feature of stock pricing during the subinterval, named the interval slope, can characterize fluctuations in stock price over specific periods. The cumulative distribution function (CDF of MSE was compared to those of MMSE-BC and SVR. We concluded that the interval slope developed here can capture more complex dynamics of stock price trends. The mean stock price can then be predicted over specific time intervals relatively accurately, in which multiple mean values over time intervals are used to express the time series in the long term. In this way, the prediction of long-term stock price can be more precise and prevent the development of cumulative errors.

  4. Event- and interval-based measurement of stuttering: a review.

    Science.gov (United States)

    Valente, Ana Rita S; Jesus, Luis M T; Hall, Andreia; Leahy, Margaret

    2015-01-01

    Event- and interval-based measurements are two different ways of computing frequency of stuttering. Interval-based methodology emerged as an alternative measure to overcome problems associated with reproducibility in the event-based methodology. No review has been made to study the effect of methodological factors in interval-based absolute reliability data or to compute the agreement between the two methodologies in terms of inter-judge, intra-judge and accuracy (i.e., correspondence between raters' scores and an established criterion). To provide a review related to reproducibility of event-based and time-interval measurement, and to verify the effect of methodological factors (training, experience, interval duration, sample presentation order and judgment conditions) on agreement of time-interval measurement; in addition, to determine if it is possible to quantify the agreement between the two methodologies The first two authors searched for articles on ERIC, MEDLINE, PubMed, B-on, CENTRAL and Dissertation Abstracts during January-February 2013 and retrieved 495 articles. Forty-eight articles were selected for review. Content tables were constructed with the main findings. Articles related to event-based measurements revealed values of inter- and intra-judge greater than 0.70 and agreement percentages beyond 80%. The articles related to time-interval measures revealed that, in general, judges with more experience with stuttering presented significantly higher levels of intra- and inter-judge agreement. Inter- and intra-judge values were beyond the references for high reproducibility values for both methodologies. Accuracy (regarding the closeness of raters' judgements with an established criterion), intra- and inter-judge agreement were higher for trained groups when compared with non-trained groups. Sample presentation order and audio/video conditions did not result in differences in inter- or intra-judge results. A duration of 5 s for an interval appears to be

  5. Measurement of subcritical multiplication by the interval distribution method

    International Nuclear Information System (INIS)

    Nelson, G.W.

    1985-01-01

    The prompt decay constant or the subcritical neutron multiplication may be determined by measuring the distribution of the time intervals between successive neutron counts. The distribution data is analyzed by least-squares fitting to a theoretical distribution function derived from a point reactor probability model. Published results of measurements with one- and two-detector systems are discussed. Data collection times are shorter, and statistical errors are smaller the nearer the system is to delayed critical. Several of the measurements indicate that a shorter data collection time and higher accuracy are possible with the interval distribution method than with the Feynman variance method

  6. Integral-Value Models for Outcomes over Continuous Time

    DEFF Research Database (Denmark)

    Harvey, Charles M.; Østerdal, Lars Peter

    Models of preferences between outcomes over continuous time are important for individual, corporate, and social decision making, e.g., medical treatment, infrastructure development, and environmental regulation. This paper presents a foundation for such models. It shows that conditions on prefere...... on preferences between real- or vector-valued outcomes over continuous time are satisfied if and only if the preferences are represented by a value function having an integral form......Models of preferences between outcomes over continuous time are important for individual, corporate, and social decision making, e.g., medical treatment, infrastructure development, and environmental regulation. This paper presents a foundation for such models. It shows that conditions...

  7. The Role of Memory and Integration in Early Time Concepts.

    Science.gov (United States)

    Levin, Iris; And Others

    1984-01-01

    A total of 630 boys and girls from kindergarten to second grade were asked to compare durations that differ in beginning times with those that differ in ending times. Possible sources of children's failure to integrate beginning and end points when comparing durations were discussed. (Author/CI)

  8. Adaptive time-stepping Monte Carlo integration of Coulomb collisions

    Science.gov (United States)

    Särkimäki, K.; Hirvijoki, E.; Terävä, J.

    2018-01-01

    We report an accessible and robust tool for evaluating the effects of Coulomb collisions on a test particle in a plasma that obeys Maxwell-Jüttner statistics. The implementation is based on the Beliaev-Budker collision integral which allows both the test particle and the background plasma to be relativistic. The integration method supports adaptive time stepping, which is shown to greatly improve the computational efficiency. The Monte Carlo method is implemented for both the three-dimensional particle momentum space and the five-dimensional guiding center phase space. Detailed description is provided for both the physics and implementation of the operator. The focus is in adaptive integration of stochastic differential equations, which is an overlooked aspect among existing Monte Carlo implementations of Coulomb collision operators. We verify that our operator converges to known analytical results and demonstrate that careless implementation of the adaptive time step can lead to severely erroneous results. The operator is provided as a self-contained Fortran 95 module and can be included into existing orbit-following tools that trace either the full Larmor motion or the guiding center dynamics. The adaptive time-stepping algorithm is expected to be useful in situations where the collision frequencies vary greatly over the course of a simulation. Examples include the slowing-down of fusion products or other fast ions, and the Dreicer generation of runaway electrons as well as the generation of fast ions or electrons with ion or electron cyclotron resonance heating.

  9. First Passage Time Intervals of Gaussian Processes

    Science.gov (United States)

    Perez, Hector; Kawabata, Tsutomu; Mimaki, Tadashi

    1987-08-01

    The first passage time problem of a stationary Guassian process is theretically and experimentally studied. Renewal functions are derived for a time-dependent boundary and numerically calculated for a Gaussian process having a seventh-order Butterworth spectrum. The results show a multipeak property not only for the constant boundary but also for a linearly increasing boundary. The first passage time distribution densities were experimentally determined for a constant boundary. The renewal functions were shown to be a fairly good approximation to the distribution density over a limited range.

  10. Interpregnancy interval and risk of autistic disorder.

    Science.gov (United States)

    Gunnes, Nina; Surén, Pål; Bresnahan, Michaeline; Hornig, Mady; Lie, Kari Kveim; Lipkin, W Ian; Magnus, Per; Nilsen, Roy Miodini; Reichborn-Kjennerud, Ted; Schjølberg, Synnve; Susser, Ezra Saul; Øyen, Anne-Siri; Stoltenberg, Camilla

    2013-11-01

    A recent California study reported increased risk of autistic disorder in children conceived within a year after the birth of a sibling. We assessed the association between interpregnancy interval and risk of autistic disorder using nationwide registry data on pairs of singleton full siblings born in Norway. We defined interpregnancy interval as the time from birth of the first-born child to conception of the second-born child in a sibship. The outcome of interest was autistic disorder in the second-born child. Analyses were restricted to sibships in which the second-born child was born in 1990-2004. Odds ratios (ORs) were estimated by fitting ordinary logistic models and logistic generalized additive models. The study sample included 223,476 singleton full-sibling pairs. In sibships with interpregnancy intervals autistic disorder, compared with 0.13% in the reference category (≥ 36 months). For interpregnancy intervals shorter than 9 months, the adjusted OR of autistic disorder in the second-born child was 2.18 (95% confidence interval 1.42-3.26). The risk of autistic disorder in the second-born child was also increased for interpregnancy intervals of 9-11 months in the adjusted analysis (OR = 1.71 [95% CI = 1.07-2.64]). Consistent with a previous report from California, interpregnancy intervals shorter than 1 year were associated with increased risk of autistic disorder in the second-born child. A possible explanation is depletion of micronutrients in mothers with closely spaced pregnancies.

  11. Effect of palady and cup feeding on premature neonates′ weight gain and reaching full oral feeding time interval

    Directory of Open Access Journals (Sweden)

    Maryam Marofi

    2016-01-01

    Full Text Available Background: Premature neonates′ feeding is of great importance due to its effective role in their growth. These neonates should reach an independent oral nutrition stage before being discharged from the Neonatal Intensive care Unit. Therefore, the researcher decided to conduct a study on the effect of palady and cup feeding on premature neonates′ weight gain and their reaching full oral feeding time interval. Materials and Methods: This is a clinical trial with a quantitative design conducted on 69 premature infants (gestational age between 29 and 32 weeks who were assigned to cup (n = 34 and palady (n = 35 feeding groups through random allocation. The first feeding was administrated either by cup or palady method in each shift within seven sequential days (total of 21 cup and palady feedings. Then, the rest of feeding was administrated by gavage. Results: Mean hospitalization time (cup = 39.01 and palady = 30.4; P < 0.001 and mean time interval to reach full oral feeding (cup = 33.7 and palady = 24.1; P < 0.001 were significantly lower in palady group compared to cup group. Mean weight changes of neonates 7 weeks after the intervention compared to those in the beginning of the intervention were significantly more in palady group compared to the cup group (cup = 146.7 and palady = 198.8; P < 0.001. Conclusions: The neonates in palady group reached full oral feeding earlier than those of cup group. Subjects′ weight gain was also higher in palady group compared to the cup group. Premature neonates with over 30 weeks of gestational age and physiological stability can be fed by palady.

  12. Integrated intensities in inverse time-of-flight technique

    International Nuclear Information System (INIS)

    Dorner, Bruno

    2006-01-01

    In traditional data analysis a model function, convoluted with the resolution, is fitted to the measured data. In case that integrated intensities of signals are of main interest, one can use an approach which does not require a model function for the signal nor detailed knowledge of the resolution. For inverse TOF technique, this approach consists of two steps: (i) Normalisation of the measured spectrum with the help of a monitor, with 1/k sensitivity, which is positioned in front of the sample. This means at the same time a conversion of the data from time of flight to energy transfer. (ii) A Jacobian [I. Waller, P.O. Froeman, Ark. Phys. 4 (1952) 183] transforms data collected at constant scattering angle into data as if measured at constant momentum transfer Q. This Jacobian works correctly for signals which have a constant width at different Q along the trajectory of constant scattering angle. The approach has been tested on spectra of Compton scattering with neutrons, having epithermal energies, obtained on the inverse TOF spectrometer VESUVIO/ISIS. In this case the width of the signal is increasing proportional to Q and in consequence the application of the Jacobian leads to integrated intensities slightly too high. The resulting integrated intensities agree very well with results derived in the traditional way. Thus this completely different approach confirms the observation that signals from recoil by H-atoms at large momentum transfers are weaker than expected

  13. Calculation of solar irradiation prediction intervals combining volatility and kernel density estimates

    International Nuclear Information System (INIS)

    Trapero, Juan R.

    2016-01-01

    In order to integrate solar energy into the grid it is important to predict the solar radiation accurately, where forecast errors can lead to significant costs. Recently, the increasing statistical approaches that cope with this problem is yielding a prolific literature. In general terms, the main research discussion is centred on selecting the “best” forecasting technique in accuracy terms. However, the need of the users of such forecasts require, apart from point forecasts, information about the variability of such forecast to compute prediction intervals. In this work, we will analyze kernel density estimation approaches, volatility forecasting models and combination of both of them in order to improve the prediction intervals performance. The results show that an optimal combination in terms of prediction interval statistical tests can achieve the desired confidence level with a lower average interval width. Data from a facility located in Spain are used to illustrate our methodology. - Highlights: • This work explores uncertainty forecasting models to build prediction intervals. • Kernel density estimators, exponential smoothing and GARCH models are compared. • An optimal combination of methods provides the best results. • A good compromise between coverage and average interval width is shown.

  14. An Intervention to Reduce the Time Interval Between Hospital Entry and Emergency Coronary Angiography in Patients with ST-Elevation Myocardial Infarction.

    Science.gov (United States)

    Karkabi, Basheer; Jaffe, Ronen; Halon, David A; Merdler, Amnon; Khader, Nader; Rubinshtein, Ronen; Goldstein, Jacob; Zafrir, Barak; Zissman, Keren; Ben-Dov, Nissan; Gabrielly, Michael; Fuks, Alex; Shiran, Avinoam; Adawi, Salim; Hellman, Yaron; Shahla, Johny; Halabi, Salim; Flugelman, Moshe Y; Cohen, Shai; Bergman, Irina; Kassem, Sameer; Shapira, Chen

    2017-09-01

    Outcomes of patients with acute ST-elevation myocardial infarction (STEMI) are strongly correlated to the time interval from hospital entry to primary percutaneous coronary intervention (PPCI). Current guidelines recommend a door to balloon time of < 90 minutes. To reduce the time from hospital admission to PPCI and to increase the proportion of patients treated within 90 minutes. In March 2013 the authors launched a seven-component intervention program:  Direct patient evacuation by out-of-hospital emergency medical services to the coronary intensive care unit or catheterization laboratory Education program for the emergency department staff Dissemination of information regarding the urgency of the PPCI decision Activation of the catheterization team by a single phone call Reimbursement for transportation costs to on-call staff who use their own cars Improvement in the quality of medical records Investigation of failed cases and feedback. During the 14 months prior to the intervention, initiation of catheterization occurred within 90 minutes of hospital arrival in 88/133 patients(65%); during the 18 months following the start of the intervention, the rate was 181/200 (90%) (P < 0.01). The respective mean/median times to treatment were 126/67 minutes and 52/47 minutes (P < 0.01). Intervention also resulted in shortening of the time interval from hospital entry to PPCI on nights and weekends. Following implementation of a comprehensive intervention, the time from hospital admission to PPCI of STEMI patients shortened significantly, as did the proportion of patients treated within 90 minutes of hospital arrival.

  15. Abuse notation of improper integrals

    Science.gov (United States)

    Arfi, E.; Wiryanto, L. H.

    2018-01-01

    In the definition of \\int_ab {f(x)dx} , it was assumed that the interval [a, b] was finite. However, in many application in physics, engineering, economics, and probability we wish to allow a or b (or both) to be infinite or for the other case when f has an infinite discontinuity in [a, b]. In either case the integral is called improper integral. Definition of improper integral is the limit of a definite integral as an endpoint of the interval of integration approaches either a specified real number or ∞ or -∞ or, in some cases, as both endpoints approach limits. Many of the first-year students in ITERA learning about improper integrals make an abuse notation like written improper integral just like standard definite integral. Based on this situation, we tried to change the habits of the students in the writing of improper integrals by providing sufficient understanding and considerable exercises. It turns out this way gives good result, based on the percentage of the value of the midterms to the problem of improper integrals give a fairly good percentage value.

  16. Global format for energy-momentum based time integration in nonlinear dynamics

    DEFF Research Database (Denmark)

    Krenk, Steen

    2014-01-01

    A global format is developed for momentum and energy consistent time integration of second‐order dynamic systems with general nonlinear stiffness. The algorithm is formulated by integrating the state‐space equations of motion over the time increment. The internal force is first represented...... of mean value products at the element level or explicit use of a geometric stiffness matrix. An optional monotonic algorithmic damping, increasing with response frequency, is developed in terms of a single damping parameter. In the solution procedure, the velocity is eliminated and the nonlinear...

  17. New Integrated Quality Function Deployment Approach Based on Interval Neutrosophic Set for Green Supplier Evaluation and Selection

    Directory of Open Access Journals (Sweden)

    Luu Huu Van

    2018-03-01

    Full Text Available Green supplier evaluation and selection plays a crucial role in the green supply chain management of any organization to reduce the purchasing cost of materials and increase the flexibility and quality of products. An interval neutrosophic set (INS—which is a generalization of fuzzy sets, intuitionistic fuzzy sets (IFS and neutrosophic sets (NS—can better handle the incomplete, indeterminate and inconsistent information than the other sets. This paper proposes a new integrated Quality Function Deployment (QFD in support of the green supplier evaluation and selection process. In the proposed approach, INS is used to assess the relative importance of the characteristics that the purchased product should have (internal variables “WHATs” in order to satisfy the company’s needs, the relevant supplier assessment criteria (external variables “HOWs”, the “HOWs”-“WHATs” correlation scores, the resulting weights of the “HOWs” and the impact of each potential supplier. The normalized weighted rating is then defined and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS method is developed to obtain a final ranking of green suppliers. A case study is applied to demonstrate the efficiency and computational procedure of the proposed method.

  18. Transits of planets with small intervals in circumbinary systems

    International Nuclear Information System (INIS)

    Liu, Hui-Gen; Wang, Ying; Zhang, Hui; Zhou, Ji-Lin

    2014-01-01

    Transit times around single stars can be described well by a linear ephemeris. However, transit times in circumbinary systems are influenced both by the gravitational perturbations and the orbital phase variations of the central binary star. Adopting a coplanar analog of Kepler-16 as an example, we find that circumbinary planets can transit the same star more than once during a single planetary orbit, a phenomenon we call 'tight transits.' In certain geometric architecture, the projected orbital velocity of the planet and the secondary star can approach zero and change sign, resulting in very long transits and/or 2-3 transits during a single binary orbit. Whether tight transits are possible for a particular system depends primarily on the binary mass ratio and the orbital architecture of both the binary and the planet. We derive a time-dependent criterion to judge when tight transits are possible for any circumbinary system. These results are verified with full dynamical integrations that also reveal other tight transit characteristics, i.e., the transit durations and the intervals between tight transits. For the seven currently known circumbinary systems, we estimate these critical parameters both analytically and numerically. Due to the mutual inclination between the planet and the binary, tight transits can only occur across the less massive star B in Kepler-16, -34, -35, and -47 (for both planets). The long-term average frequency of tight transits (compared to typical transits) for Kepler-16, -34, and -35 are estimated to be several percent. Using full numerical integrations, the next tight transit for each system is predicted and the soonest example appears to be Kepler-47b and -47c, which are likely to have tight transits before 2025. These unique and valuable events often deserve special observational scrutiny.

  19. Reliability-Based and Cost-Oriented Product Optimization Integrating Fuzzy Reasoning Petri Nets, Interval Expert Evaluation and Cultural-Based DMOPSO Using Crowding Distance Sorting

    Directory of Open Access Journals (Sweden)

    Zhaoxi Hong

    2017-08-01

    Full Text Available In reliability-based and cost-oriented product optimization, the target product reliability is apportioned to subsystems or components to achieve the maximum reliability and minimum cost. Main challenges to conducting such optimization design lie in how to simultaneously consider subsystem division, uncertain evaluation provided by experts for essential factors, and dynamic propagation of product failure. To overcome these problems, a reliability-based and cost-oriented product optimization method integrating fuzzy reasoning Petri net (FRPN, interval expert evaluation and cultural-based dynamic multi-objective particle swarm optimization (DMOPSO using crowding distance sorting is proposed in this paper. Subsystem division is performed based on failure decoupling, and then subsystem weights are calculated with FRPN reflecting dynamic and uncertain failure propagation, as well as interval expert evaluation considering six essential factors. A mathematical model of reliability-based and cost-oriented product optimization is established, and the cultural-based DMOPSO with crowding distance sorting is utilized to obtain the optimized design scheme. The efficiency and effectiveness of the proposed method are demonstrated by the numerical example of the optimization design for a computer numerically controlled (CNC machine tool.

  20. Interpregnancy intervals: impact of postpartum contraceptive effectiveness and coverage.

    Science.gov (United States)

    Thiel de Bocanegra, Heike; Chang, Richard; Howell, Mike; Darney, Philip

    2014-04-01

    The purpose of this study was to determine the use of contraceptive methods, which was defined by effectiveness, length of coverage, and their association with short interpregnancy intervals, when controlling for provider type and client demographics. We identified a cohort of 117,644 women from the 2008 California Birth Statistical Master file with second or higher order birth and at least 1 Medicaid (Family Planning, Access, Care, and Treatment [Family PACT] program or Medi-Cal) claim within 18 months after index birth. We explored the effect of contraceptive method provision on the odds of having an optimal interpregnancy interval and controlled for covariates. The average length of contraceptive coverage was 3.81 months (SD = 4.84). Most women received user-dependent hormonal contraceptives as their most effective contraceptive method (55%; n = 65,103 women) and one-third (33%; n = 39,090 women) had no contraceptive claim. Women who used long-acting reversible contraceptive methods had 3.89 times the odds and women who used user-dependent hormonal methods had 1.89 times the odds of achieving an optimal birth interval compared with women who used barrier methods only; women with no method had 0.66 times the odds. When user-dependent methods are considered, the odds of having an optimal birth interval increased for each additional month of contraceptive coverage by 8% (odds ratio, 1.08; 95% confidence interval, 1.08-1.09). Women who were seen by Family PACT or by both Family PACT and Medi-Cal providers had significantly higher odds of optimal birth intervals compared with women who were served by Medi-Cal only. To achieve optimal birth spacing and ultimately to improve birth outcomes, attention should be given to contraceptive counseling and access to contraceptive methods in the postpartum period. Copyright © 2014 Mosby, Inc. All rights reserved.

  1. Prognostic Value of Cardiac Time Intervals by Tissue Doppler Imaging M-Mode in Patients With Acute ST-Segment-Elevation Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

    DEFF Research Database (Denmark)

    Biering-Sørensen, Tor; Mogelvang, Rasmus; Søgaard, Peter

    2013-01-01

    Background- Color tissue Doppler imaging M-mode through the mitral leaflet is an easy and precise method to estimate all cardiac time intervals from 1 cardiac cycle and thereby obtain the myocardial performance index (MPI). However, the prognostic value of the cardiac time intervals and the MPI...... assessed by color tissue Doppler imaging M-mode through the mitral leaflet in patients with ST-segment-elevation myocardial infarction (MI) is unknown. Methods and Results- In total, 391 patients were admitted with an ST-segment-elevation MI, treated with primary percutaneous coronary intervention...

  2. Chaos on the interval

    CERN Document Server

    Ruette, Sylvie

    2017-01-01

    The aim of this book is to survey the relations between the various kinds of chaos and related notions for continuous interval maps from a topological point of view. The papers on this topic are numerous and widely scattered in the literature; some of them are little known, difficult to find, or originally published in Russian, Ukrainian, or Chinese. Dynamical systems given by the iteration of a continuous map on an interval have been broadly studied because they are simple but nevertheless exhibit complex behaviors. They also allow numerical simulations, which enabled the discovery of some chaotic phenomena. Moreover, the "most interesting" part of some higher-dimensional systems can be of lower dimension, which allows, in some cases, boiling it down to systems in dimension one. Some of the more recent developments such as distributional chaos, the relation between entropy and Li-Yorke chaos, sequence entropy, and maps with infinitely many branches are presented in book form for the first time. The author gi...

  3. A Time Interval of More Than 18 Months Between a Pregnancy and a Roux-en-Y Gastric Bypass Increases the Risk of Iron Deficiency and Anaemia in Pregnancy.

    Science.gov (United States)

    Crusell, Mie; Nilas, Lisbeth; Svare, Jens; Lauenborg, Jeannet

    2016-10-01

    The aim of the study is to explore the impact of time between Roux-en-Y gastric bypass (RYGB) and pregnancy on obstetrical outcome and nutritional derangements. In a retrospective cross-sectional study of pregnant women admitted for antenatal care at two tertiary hospitals, we examined 153 women with RYGB and a singleton pregnancy of at least 24 weeks. The women were stratified according to a pregnancy pregnancy, gestational hypertension, length of pregnancy, mode of delivery and foetal birth weight. The two groups were comparable regarding age, parity and prepregnancy body mass index. The frequency of iron deficiency anaemia (ferritin pregnancy outcome or birth weight between the two groups. A long surgery-to-pregnancy time interval after a RYGB increases the risk of iron deficiency anaemia but not of other nutritional deficits. Time interval does not seem to have an adverse effect on the obstetrical outcome, including intrauterine growth restriction. Specific attention is needed on iron deficit with increasing surgery-to-pregnancy time interval.

  4. A probabilistic approach for representation of interval uncertainty

    International Nuclear Information System (INIS)

    Zaman, Kais; Rangavajhala, Sirisha; McDonald, Mark P.; Mahadevan, Sankaran

    2011-01-01

    In this paper, we propose a probabilistic approach to represent interval data for input variables in reliability and uncertainty analysis problems, using flexible families of continuous Johnson distributions. Such a probabilistic representation of interval data facilitates a unified framework for handling aleatory and epistemic uncertainty. For fitting probability distributions, methods such as moment matching are commonly used in the literature. However, unlike point data where single estimates for the moments of data can be calculated, moments of interval data can only be computed in terms of upper and lower bounds. Finding bounds on the moments of interval data has been generally considered an NP-hard problem because it includes a search among the combinations of multiple values of the variables, including interval endpoints. In this paper, we present efficient algorithms based on continuous optimization to find the bounds on second and higher moments of interval data. With numerical examples, we show that the proposed bounding algorithms are scalable in polynomial time with respect to increasing number of intervals. Using the bounds on moments computed using the proposed approach, we fit a family of Johnson distributions to interval data. Furthermore, using an optimization approach based on percentiles, we find the bounding envelopes of the family of distributions, termed as a Johnson p-box. The idea of bounding envelopes for the family of Johnson distributions is analogous to the notion of empirical p-box in the literature. Several sets of interval data with different numbers of intervals and type of overlap are presented to demonstrate the proposed methods. As against the computationally expensive nested analysis that is typically required in the presence of interval variables, the proposed probabilistic representation enables inexpensive optimization-based strategies to estimate bounds on an output quantity of interest.

  5. Estudio controlado sobre la eficacia de una valoración e intervención integral en pacientes ancianos ingresados en una unidad de convalecencia geriátrica

    OpenAIRE

    Vázquez Ibar, Olga

    2016-01-01

    La valoración geriátrica integral es un proceso diagnóstico multidimensional e interdisciplinar que detecta necesidades y capacidades funcionales, cognitivas y sociales de ancianos, así como problemas médicos para establecer planes de intervención y seguimiento individualizados. Aunque se realiza en muchos entornos asistenciales, las unidades de convalecencia ofrecen intervenciones geriátricas intensas y prolongadas en el tiempo que generan efectos positivos en la salud de los ancianos. Ob...

  6. Computation of robustly stabilizing PID controllers for interval systems.

    Science.gov (United States)

    Matušů, Radek; Prokop, Roman

    2016-01-01

    The paper is focused on the computation of all possible robustly stabilizing Proportional-Integral-Derivative (PID) controllers for plants with interval uncertainty. The main idea of the proposed method is based on Tan's (et al.) technique for calculation of (nominally) stabilizing PI and PID controllers or robustly stabilizing PI controllers by means of plotting the stability boundary locus in either P-I plane or P-I-D space. Refinement of the existing method by consideration of 16 segment plants instead of 16 Kharitonov plants provides an elegant and efficient tool for finding all robustly stabilizing PID controllers for an interval system. The validity and relatively effortless application of presented theoretical concepts are demonstrated through a computation and simulation example in which the uncertain mathematical model of an experimental oblique wing aircraft is robustly stabilized.

  7. An integrated framework for SAGD real-time monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Mohajer, M.; Perez-Damas, C.; Berbin, A.; Al-kinani, A. [Schlumberger, Calgary, AB (Canada)

    2009-07-01

    This study examined the technologies and workflows for real-time optimization (RTO) of the steam assisted gravity drainage (SAGD) process. Although SAGD operators have tried to control the reservoir's steam chamber distribution to optimize bitumen recovery and minimize steam oil ratios, a true optimization can only be accomplished by implementing RTO workflows. In order for these workflows to be successful, some elements must be properly designed and introduced into the system. Most notably, well completions must ensure the integrity of downhole sensors; the appropriate measuring instruments must be selected; and surface and downhole measurements must be obtained. Operators have not been early adopters of RTO workflows for SAGD because of the numerous parameters that must be monitored, harsh operating conditions, the lack of integration between the different data acquisition systems, and the complex criteria required to optimize SAGD performance. This paper discussed the first stage in the development of a fully integrated RTO workflow for SAGD. An experimental apparatus with fiber optics distributed temperature sensing (DTS) was connected to a data acquisition system, and intra-minute data was streamed directly into an engineering desktop. The paper showed how subcool calculations can be effectively performed along the length of the horizontal well in real time and the results used to improve SAGD operation. Observations were compared against simulated predictions. In the next stage, a more complex set of criteria will be derived and additional data will be incorporated, such as surface heave, cross-well microseismic, multiphase flowmeter, and observation wells. 9 refs., 9 tabs., 13 figs.

  8. Self-adaptive numerical integrator for analytic functions

    International Nuclear Information System (INIS)

    Garribba, S.; Quartapelle, L.; Reina, G.

    1978-01-01

    A new adaptive algorithm for the integration of analytical functions is presented. The algorithm processes the integration interval by generating local subintervals whose length is controlled through a feedback loop. The control is obtained by means of a relation derived on an analytical basis and valid for an arbitrary integration rule: two different estimates of an integral are used to compute the interval length necessary to obtain an integral estimate with accuracy within the assigned error bounds. The implied method for local generation of subintervals and an effective assumption of error partition among subintervals give rise to an adaptive algorithm provided with a highly accurate and very efficient integration procedure. The particular algorithm obtained by choosing the 6-point Gauss-Legendre integration rule is considered and extensive comparisons are made with other outstanding integration algorithms

  9. On Tuning PI Controllers for Integrating Plus Time Delay Systems

    Directory of Open Access Journals (Sweden)

    David Di Ruscio

    2010-10-01

    Full Text Available Some analytical results concerning PI controller tuning based on integrator plus time delay models are worked out and presented. A method for obtaining PI controller parameters, Kp=alpha/(k*tau, and, Ti=beta*tau, which ensures a given prescribed maximum time delay error, dtau_max, to time delay, tau, ratio parameter delta=dau_max/tau, is presented. The corner stone in this method, is a method product parameter, c=alpha*beta. Analytical relations between the PI controller parameters, Ti, and, Kp, and the time delay error parameter, delta, is presented, and we propose the setting, beta=c/a*(delta+1, and, alpha=a/(delta+1, which gives, Ti=c/a*(delta+1*tau, and Kp=a/((delta+1*k*tau, where the parameter, a, is constant in the method product parameter, c=alpha*beta. It also turns out that the integral time, Ti, is linear in, delta, and the proportional gain, Kp, inversely proportional to, delta+1. For the original Ziegler Nichols (ZN method this parameter is approximately, c=2.38, and the presented method may e.g., be used to obtain new modified ZN parameters with increased robustness margins, also documented in the paper.

  10. Integral Time and the Varieties of Post-Mortem Survival

    Directory of Open Access Journals (Sweden)

    Sean M. Kelly

    2008-06-01

    Full Text Available While the question of survival of bodily death is usually approached byfocusing on the mind/body relation (and often with the idea of the soul as a special kindof substance, this paper explores the issue in the context of our understanding of time.The argument of the paper is woven around the central intuition of time as an “everlivingpresent.” The development of this intuition allows for a more integral or “complexholistic”theory of time, the soul, and the question of survival. Following the introductorymatter, the first section proposes a re-interpretation of Nietzsche’s doctrine of eternalrecurrence in terms of moments and lives as “eternally occurring.” The next section is atreatment of Julian Barbour’s neo-Machian model of instants of time as configurations inthe n-dimensional phase-space he calls “Platonia.” While rejecting his claim to have doneaway with time, I do find his model suggestive of the idea of moments and lives aseternally occurring. The following section begins with Fechner’s visionary ideas of thenature of the soul and its survival of bodily death, with particular attention to the notionof holonic inclusion and the central analogy of the transition from perception to memory.I turn next to Whitehead’s equally holonic notions of prehension and the concrescence ofactual occasions. From his epochal theory of time and certain ambiguities in hisreflections on the “divine antinomies,” we are brought to the threshold of a potentiallymore integral or “complex-holistic” theory of time and survival, which is treated in thelast section. This section draws from my earlier work on Hegel, Jung, and Edgar Morin,as well as from key insights of Jean Gebser, for an interpretation of Sri Aurobindo’sinspired but cryptic description of the “Supramental Time Vision.” This interpretationleads to an alternative understanding of reincarnation—and to the possibility of itsreconciliation with the once-only view

  11. Synchronization of Switched Interval Networks and Applications to Chaotic Neural Networks

    OpenAIRE

    Cao, Jinde; Alofi, Abdulaziz; Al-Mazrooei, Abdullah; Elaiw, Ahmed

    2013-01-01

    This paper investigates synchronization problem of switched delay networks with interval parameters uncertainty, based on the theories of the switched systems and drive-response technique, a mathematical model of the switched interval drive-response error system is established. Without constructing Lyapunov-Krasovskii functions, introducing matrix measure method for the first time to switched time-varying delay networks, combining Halanay inequality technique, synchroniza...

  12. A discontinous Galerkin finite element method with an efficient time integration scheme for accurate simulations

    KAUST Repository

    Liu, Meilin

    2011-07-01

    A discontinuous Galerkin finite element method (DG-FEM) with a highly-accurate time integration scheme is presented. The scheme achieves its high accuracy using numerically constructed predictor-corrector integration coefficients. Numerical results show that this new time integration scheme uses considerably larger time steps than the fourth-order Runge-Kutta method when combined with a DG-FEM using higher-order spatial discretization/basis functions for high accuracy. © 2011 IEEE.

  13. HMC algorithm with multiple time scale integration and mass preconditioning

    Science.gov (United States)

    Urbach, C.; Jansen, K.; Shindler, A.; Wenger, U.

    2006-01-01

    We present a variant of the HMC algorithm with mass preconditioning (Hasenbusch acceleration) and multiple time scale integration. We have tested this variant for standard Wilson fermions at β=5.6 and at pion masses ranging from 380 to 680 MeV. We show that in this situation its performance is comparable to the recently proposed HMC variant with domain decomposition as preconditioner. We give an update of the "Berlin Wall" figure, comparing the performance of our variant of the HMC algorithm to other published performance data. Advantages of the HMC algorithm with mass preconditioning and multiple time scale integration are that it is straightforward to implement and can be used in combination with a wide variety of lattice Dirac operators.

  14. Floral pathway integrator gene expression mediates gradual transmission of environmental and endogenous cues to flowering time.

    Science.gov (United States)

    van Dijk, Aalt D J; Molenaar, Jaap

    2017-01-01

    The appropriate timing of flowering is crucial for the reproductive success of plants. Hence, intricate genetic networks integrate various environmental and endogenous cues such as temperature or hormonal statues. These signals integrate into a network of floral pathway integrator genes. At a quantitative level, it is currently unclear how the impact of genetic variation in signaling pathways on flowering time is mediated by floral pathway integrator genes. Here, using datasets available from literature, we connect Arabidopsis thaliana flowering time in genetic backgrounds varying in upstream signalling components with the expression levels of floral pathway integrator genes in these genetic backgrounds. Our modelling results indicate that flowering time depends in a quite linear way on expression levels of floral pathway integrator genes. This gradual, proportional response of flowering time to upstream changes enables a gradual adaptation to changing environmental factors such as temperature and light.

  15. Floral pathway integrator gene expression mediates gradual transmission of environmental and endogenous cues to flowering time

    Directory of Open Access Journals (Sweden)

    Aalt D.J. van Dijk

    2017-04-01

    Full Text Available The appropriate timing of flowering is crucial for the reproductive success of plants. Hence, intricate genetic networks integrate various environmental and endogenous cues such as temperature or hormonal statues. These signals integrate into a network of floral pathway integrator genes. At a quantitative level, it is currently unclear how the impact of genetic variation in signaling pathways on flowering time is mediated by floral pathway integrator genes. Here, using datasets available from literature, we connect Arabidopsis thaliana flowering time in genetic backgrounds varying in upstream signalling components with the expression levels of floral pathway integrator genes in these genetic backgrounds. Our modelling results indicate that flowering time depends in a quite linear way on expression levels of floral pathway integrator genes. This gradual, proportional response of flowering time to upstream changes enables a gradual adaptation to changing environmental factors such as temperature and light.

  16. Transmission line sag calculations using interval mathematics

    Energy Technology Data Exchange (ETDEWEB)

    Shaalan, H. [Institute of Electrical and Electronics Engineers, Washington, DC (United States)]|[US Merchant Marine Academy, Kings Point, NY (United States)

    2007-07-01

    Electric utilities are facing the need for additional generating capacity, new transmission systems and more efficient use of existing resources. As such, there are several uncertainties associated with utility decisions. These uncertainties include future load growth, construction times and costs, and performance of new resources. Regulatory and economic environments also present uncertainties. Uncertainty can be modeled based on a probabilistic approach where probability distributions for all of the uncertainties are assumed. Another approach to modeling uncertainty is referred to as unknown but bounded. In this approach, the upper and lower bounds on the uncertainties are assumed without probability distributions. Interval mathematics is a tool for the practical use and extension of the unknown but bounded concept. In this study, the calculation of transmission line sag was used as an example to demonstrate the use of interval mathematics. The objective was to determine the change in cable length, based on a fixed span and an interval of cable sag values for a range of temperatures. The resulting change in cable length was an interval corresponding to the interval of cable sag values. It was shown that there is a small change in conductor length due to variation in sag based on the temperature ranges used in this study. 8 refs.

  17. INTEGRITY ANALYSIS OF REAL-TIME PPP TECHNIQUE WITH IGS-RTS SERVICE FOR MARITIME NAVIGATION

    Directory of Open Access Journals (Sweden)

    M. El-Diasty

    2017-10-01

    Full Text Available Open sea and inland waterways are the most widely used mode for transporting goods worldwide. It is the International Maritime Organization (IMO that defines the requirements for position fixing equipment for a worldwide radio-navigation system, in terms of accuracy, integrity, continuity, availability and coverage for the various phases of navigation. Satellite positioning systems can contribute to meet these requirements, as well as optimize marine transportation. Marine navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with alert limit ranges from 25 m to 0.25 m. GPS positioning is widely used for many applications and is currently recognized by IMO for a future maritime navigation. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP and with the advent of new real-time GNSS correction services such as IGS-Real-Time-Service (RTS, it is necessary to investigate the integrity of the PPP-based positioning technique along with IGS-RTS service in terms of availability and reliability for safe navigation in maritime application. This paper monitors the integrity of an autonomous real-time PPP-based GPS positioning system using the IGS real-time service (RTS for maritime applications that require minimum availability of integrity of 99.8 % to fulfil the IMO integrity standards. To examine the integrity of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is collected onboard a vessel and investigated with the real-time IGS-RTS PPP-based GPS positioning technique. It is shown that the availability of integrity of the real-time IGS-RTS PPP-based GPS solution is 100 % for all navigation phases and therefore fulfil the IMO integrity standards (99.8 % availability immediately (after 1 second, after 2 minutes and after 42 minutes

  18. Integrity Analysis of Real-Time Ppp Technique with Igs-Rts Service for Maritime Navigation

    Science.gov (United States)

    El-Diasty, M.

    2017-10-01

    Open sea and inland waterways are the most widely used mode for transporting goods worldwide. It is the International Maritime Organization (IMO) that defines the requirements for position fixing equipment for a worldwide radio-navigation system, in terms of accuracy, integrity, continuity, availability and coverage for the various phases of navigation. Satellite positioning systems can contribute to meet these requirements, as well as optimize marine transportation. Marine navigation usually consists of three major phases identified as Ocean/Coastal/Port approach/Inland waterway, in port navigation and automatic docking with alert limit ranges from 25 m to 0.25 m. GPS positioning is widely used for many applications and is currently recognized by IMO for a future maritime navigation. With the advancement in autonomous GPS positioning techniques such as Precise Point Positioning (PPP) and with the advent of new real-time GNSS correction services such as IGS-Real-Time-Service (RTS), it is necessary to investigate the integrity of the PPP-based positioning technique along with IGS-RTS service in terms of availability and reliability for safe navigation in maritime application. This paper monitors the integrity of an autonomous real-time PPP-based GPS positioning system using the IGS real-time service (RTS) for maritime applications that require minimum availability of integrity of 99.8 % to fulfil the IMO integrity standards. To examine the integrity of the real-time IGS-RTS PPP-based technique for maritime applications, kinematic data from a dual frequency GPS receiver is collected onboard a vessel and investigated with the real-time IGS-RTS PPP-based GPS positioning technique. It is shown that the availability of integrity of the real-time IGS-RTS PPP-based GPS solution is 100 % for all navigation phases and therefore fulfil the IMO integrity standards (99.8 % availability) immediately (after 1 second), after 2 minutes and after 42 minutes of convergence

  19. Chosen interval methods for solving linear interval systems with special type of matrix

    Science.gov (United States)

    Szyszka, Barbara

    2013-10-01

    The paper is devoted to chosen direct interval methods for solving linear interval systems with special type of matrix. This kind of matrix: band matrix with a parameter, from finite difference problem is obtained. Such linear systems occur while solving one dimensional wave equation (Partial Differential Equations of hyperbolic type) by using the central difference interval method of the second order. Interval methods are constructed so as the errors of method are enclosed in obtained results, therefore presented linear interval systems contain elements that determining the errors of difference method. The chosen direct algorithms have been applied for solving linear systems because they have no errors of method. All calculations were performed in floating-point interval arithmetic.

  20. An efficient explicit marching on in time solver for magnetic field volume integral equation

    KAUST Repository

    Sayed, Sadeed Bin; Ulku, H. Arda; Bagci, Hakan

    2015-01-01

    An efficient explicit marching on in time (MOT) scheme for solving the magnetic field volume integral equation is proposed. The MOT system is cast in the form of an ordinary differential equation and is integrated in time using a PE(CE)m multistep

  1. Optimal distribution of integration time for intensity measurements in degree of linear polarization polarimetry.

    Science.gov (United States)

    Li, Xiaobo; Hu, Haofeng; Liu, Tiegen; Huang, Bingjing; Song, Zhanjie

    2016-04-04

    We consider the degree of linear polarization (DOLP) polarimetry system, which performs two intensity measurements at orthogonal polarization states to estimate DOLP. We show that if the total integration time of intensity measurements is fixed, the variance of the DOLP estimator depends on the distribution of integration time for two intensity measurements. Therefore, by optimizing the distribution of integration time, the variance of the DOLP estimator can be decreased. In this paper, we obtain the closed-form solution of the optimal distribution of integration time in an approximate way by employing Delta method and Lagrange multiplier method. According to the theoretical analyses and real-world experiments, it is shown that the variance of the DOLP estimator can be decreased for any value of DOLP. The method proposed in this paper can effectively decrease the measurement variance and thus statistically improve the measurement accuracy of the polarimetry system.

  2. Molecular radiotherapy: The NUKFIT software for calculating the time-integrated activity coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Kletting, P.; Schimmel, S.; Luster, M. [Klinik für Nuklearmedizin, Universität Ulm, Ulm 89081 (Germany); Kestler, H. A. [Research Group Bioinformatics and Systems Biology, Institut für Neuroinformatik, Universität Ulm, Ulm 89081 (Germany); Hänscheid, H.; Fernández, M.; Lassmann, M. [Klinik für Nuklearmedizin, Universität Würzburg, Würzburg 97080 (Germany); Bröer, J. H.; Nosske, D. [Bundesamt für Strahlenschutz, Fachbereich Strahlenschutz und Gesundheit, Oberschleißheim 85764 (Germany); Glatting, G. [Medical Radiation Physics/Radiation Protection, Medical Faculty Mannheim, Heidelberg University, Mannheim 68167 (Germany)

    2013-10-15

    Purpose: Calculation of the time-integrated activity coefficient (residence time) is a crucial step in dosimetry for molecular radiotherapy. However, available software is deficient in that it is either not tailored for the use in molecular radiotherapy and/or does not include all required estimation methods. The aim of this work was therefore the development and programming of an algorithm which allows for an objective and reproducible determination of the time-integrated activity coefficient and its standard error.Methods: The algorithm includes the selection of a set of fitting functions from predefined sums of exponentials and the choice of an error model for the used data. To estimate the values of the adjustable parameters an objective function, depending on the data, the parameters of the error model, the fitting function and (if required and available) Bayesian information, is minimized. To increase reproducibility and user-friendliness the starting values are automatically determined using a combination of curve stripping and random search. Visual inspection, the coefficient of determination, the standard error of the fitted parameters, and the correlation matrix are provided to evaluate the quality of the fit. The functions which are most supported by the data are determined using the corrected Akaike information criterion. The time-integrated activity coefficient is estimated by analytically integrating the fitted functions. Its standard error is determined assuming Gaussian error propagation. The software was implemented using MATLAB.Results: To validate the proper implementation of the objective function and the fit functions, the results of NUKFIT and SAAM numerical, a commercially available software tool, were compared. The automatic search for starting values was successfully tested for reproducibility. The quality criteria applied in conjunction with the Akaike information criterion allowed the selection of suitable functions. Function fit

  3. Time interval measurement between two emissions: Kr + Au; Mesure de l`intervalle de temps entre deux emissions: Kr + Au

    Energy Technology Data Exchange (ETDEWEB)

    Aboufirassi, M; Bougault, R.; Brou, R.; Colin, J.; Durand, D.; Genoux-Lubain, A.; Horn, D.; Laville, J.L.; Le Brun, C.; Lecolley, J.F.; Lefebvres, F.; Lopez, O.; Louvel, M.; Mahi, M.; Steckmeyer, J.C.; Tamain, B. [Lab. de Physique Corpusculaire, Caen Univ., 14 (France); LPC (Caen) - CRN (Strasbourg) - GANIL Collaboration

    1998-04-01

    To indicate the method allowing the determination of the emission intervals, the results obtained with the Kr + Au system at 43 and 60 A.MeV are presented. The experiments were performed with the NAUTILUS exclusive detectors. Central collisions were selected by means of a relative velocity criterion to reject the events containing a forward emitted fragment. For the two bombardment energies the data analysis shows that the formation of a compound of mass around A = 200. By comparing the fragment dynamical variables with simulations one can conclude about the simultaneity of the compound deexcitation processes. It was found that a 5 MeV/A is able to reproduce the characteristics of the detected fragments. Also, it was found that to reproduce the dynamical characteristics of the fragments issued from central collisions it was not necessary to superimpose a radial collective energy upon the Coulomb and thermal motion. The distribution of the relative angles between detected fragments is used here as a chronometer. For simultaneous ruptures the small relative angles are forbidden by the Coulomb repulsion, while for sequential processes this interdiction is the more lifted the longer the interval between the two emissions is. For the system discussed here the comparison between simulation and data has been carried out for the extreme cases, i.e. for a vanishing and infinite time interval between the two emissions, respectively. More sophisticated simulations to describe angular distributions between the emitted fragments were also developed 2 refs.

  4. Velocity time integral for right upper pulmonary vein in VLBW infants with patent ductus arteriosus

    Directory of Open Access Journals (Sweden)

    Gianluca Lista

    Full Text Available OBJECTIVE: Early diagnosis of significant patent ductus arteriosus reduces the risk of clinical worsening in very low birth weight infants. Echocardiographic patent ductus arteriosus shunt flow pattern can be used to predict significant patent ductus arteriosus. Pulmonary venous flow, expressed as vein velocity time integral, is correlated to ductus arteriosus closure. The aim of this study is to investigate the relationship between significant reductions in vein velocity time integral and non-significant patent ductus arteriosus in the first week of life. METHODS: A multicenter, prospective, observational study was conducted to evaluate very low birth weight infants (<1500 g on respiratory support. Echocardiography was used to evaluate vein velocity time integral on days 1 and 4 of life. The relationship between vein velocity time integral and other parameters was studied. RESULTS: In total, 98 very low birth weight infants on respiratory support were studied. On day 1 of life, vein velocity time integral was similar in patients with open or closed ductus. The mean vein velocity time integral significantly reduced in the first four days of life. On the fourth day of life, there was less of a reduction in patients with patent ductus compared to those with closed patent ductus arteriosus and the difference was significant. CONCLUSIONS: A significant reduction in vein velocity time integral in the first days of life is associated with ductus closure. This parameter correlates well with other echocardiographic parameters and may aid in the diagnosis and management of patent ductus arteriosus.

  5. Results from an Interval Management (IM) Flight Test and Its Potential Benefit to Air Traffic Management Operations

    Science.gov (United States)

    Baxley, Brian; Swieringa, Kurt; Berckefeldt, Rick; Boyle, Dan

    2017-01-01

    NASA's first Air Traffic Management Technology Demonstration (ATD-1) subproject successfully completed a 19-day flight test of an Interval Management (IM) avionics prototype. The prototype was built based on IM standards, integrated into two test aircraft, and then flown in real-world conditions to determine if the goals of improving aircraft efficiency and airport throughput during high-density arrival operations could be met. The ATD-1 concept of operation integrates advanced arrival scheduling, controller decision support tools, and the IM avionics to enable multiple time-based arrival streams into a high-density terminal airspace. IM contributes by calculating airspeeds that enable an aircraft to achieve a spacing interval behind the preceding aircraft. The IM avionics uses its data (route of flight, position, etc.) and Automatic Dependent Surveillance-Broadcast (ADS-B) state data from the Target aircraft to calculate this airspeed. The flight test demonstrated that the IM avionics prototype met the spacing accuracy design goal for three of the four IM operation types tested. The primary issue requiring attention for future IM work is the high rate of IM speed commands and speed reversals. In total, during this flight test, the IM avionics prototype showed significant promise in contributing to the goals of improving aircraft efficiency and airport throughput.

  6. Symmetric and arbitrarily high-order Birkhoff-Hermite time integrators and their long-time behaviour for solving nonlinear Klein-Gordon equations

    Science.gov (United States)

    Liu, Changying; Iserles, Arieh; Wu, Xinyuan

    2018-03-01

    The Klein-Gordon equation with nonlinear potential occurs in a wide range of application areas in science and engineering. Its computation represents a major challenge. The main theme of this paper is the construction of symmetric and arbitrarily high-order time integrators for the nonlinear Klein-Gordon equation by integrating Birkhoff-Hermite interpolation polynomials. To this end, under the assumption of periodic boundary conditions, we begin with the formulation of the nonlinear Klein-Gordon equation as an abstract second-order ordinary differential equation (ODE) and its operator-variation-of-constants formula. We then derive a symmetric and arbitrarily high-order Birkhoff-Hermite time integration formula for the nonlinear abstract ODE. Accordingly, the stability, convergence and long-time behaviour are rigorously analysed once the spatial differential operator is approximated by an appropriate positive semi-definite matrix, subject to suitable temporal and spatial smoothness. A remarkable characteristic of this new approach is that the requirement of temporal smoothness is reduced compared with the traditional numerical methods for PDEs in the literature. Numerical results demonstrate the advantage and efficiency of our time integrators in comparison with the existing numerical approaches.

  7. Magnetic Resonance Fingerprinting with short relaxation intervals.

    Science.gov (United States)

    Amthor, Thomas; Doneva, Mariya; Koken, Peter; Sommer, Karsten; Meineke, Jakob; Börnert, Peter

    2017-09-01

    The aim of this study was to investigate a technique for improving the performance of Magnetic Resonance Fingerprinting (MRF) in repetitive sampling schemes, in particular for 3D MRF acquisition, by shortening relaxation intervals between MRF pulse train repetitions. A calculation method for MRF dictionaries adapted to short relaxation intervals and non-relaxed initial spin states is presented, based on the concept of stationary fingerprints. The method is applicable to many different k-space sampling schemes in 2D and 3D. For accuracy analysis, T 1 and T 2 values of a phantom are determined by single-slice Cartesian MRF for different relaxation intervals and are compared with quantitative reference measurements. The relevance of slice profile effects is also investigated in this case. To further illustrate the capabilities of the method, an application to in-vivo spiral 3D MRF measurements is demonstrated. The proposed computation method enables accurate parameter estimation even for the shortest relaxation intervals, as investigated for different sampling patterns in 2D and 3D. In 2D Cartesian measurements, we achieved a scan acceleration of more than a factor of two, while maintaining acceptable accuracy: The largest T 1 values of a sample set deviated from their reference values by 0.3% (longest relaxation interval) and 2.4% (shortest relaxation interval). The largest T 2 values showed systematic deviations of up to 10% for all relaxation intervals, which is discussed. The influence of slice profile effects for multislice acquisition is shown to become increasingly relevant for short relaxation intervals. In 3D spiral measurements, a scan time reduction of 36% was achieved, maintaining the quality of in-vivo T1 and T2 maps. Reducing the relaxation interval between MRF sequence repetitions using stationary fingerprint dictionaries is a feasible method to improve the scan efficiency of MRF sequences. The method enables fast implementations of 3D spatially

  8. Stability Analysis and Variational Integrator for Real-Time Formation Based on Potential Field

    Directory of Open Access Journals (Sweden)

    Shengqing Yang

    2014-01-01

    Full Text Available This paper investigates a framework of real-time formation of autonomous vehicles by using potential field and variational integrator. Real-time formation requires vehicles to have coordinated motion and efficient computation. Interactions described by potential field can meet the former requirement which results in a nonlinear system. Stability analysis of such nonlinear system is difficult. Our methodology of stability analysis is discussed in error dynamic system. Transformation of coordinates from inertial frame to body frame can help the stability analysis focus on the structure instead of particular coordinates. Then, the Jacobian of reduced system can be calculated. It can be proved that the formation is stable at the equilibrium point of error dynamic system with the effect of damping force. For consideration of calculation, variational integrator is introduced. It is equivalent to solving algebraic equations. Forced Euler-Lagrange equation in discrete expression is used to construct a forced variational integrator for vehicles in potential field and obstacle environment. By applying forced variational integrator on computation of vehicles' motion, real-time formation of vehicles in obstacle environment can be implemented. Algorithm based on forced variational integrator is designed for a leader-follower formation.

  9. The Alteration of Emotion Regulation Precedes the Deficits in Interval Timing in the BACHD Rat Model for Huntington Disease

    Directory of Open Access Journals (Sweden)

    Daniel Garces

    2018-05-01

    Full Text Available Huntington disease (HD is an autosomal dominantly inherited, progressive neurodegenerative disorder which is accompanied by executive dysfunctions and emotional alteration. The aim of the present study was to assess the impact of emotion/stress on on-going highly demanding cognitive tasks, i.e., temporal processing, as a function of age in BACHD rats (a “full length” model of HD. Middle-aged (4–6 months and old (10–12 months rats were first trained on a 2 vs. 8-s temporal discrimination task, and then exposed to a series of bisection tests under normal and stressful (10 mild unpredictable foot-shocks conditions. The animals were then trained on a peak interval task, in which reinforced fixed-interval (FI 30-s trials were randomly intermixed with non-reinforced probe trials. After training, the effect of stress upon time perception was again assessed. Sensitivity to foot-shocks was also assessed independently. The results show effects of both age and genotype, with largely greater effects in old BACHD animals. The older BACHD animals had impaired learning in both tasks, but reached equivalent levels of performance as WT animals at the end of training in the temporal discrimination task, while remaining impaired in the peak interval task. Whereas sensitivity to foot-shock did not differ between BACHD and WT rats, delivery of foot-shocks during the test sessions had a disruptive impact on temporal behavior in WT animals, an effect which increased with age. In contrast, BACHD rats, independent of age, did not show any significant disruption under stress. In conclusion, BACHD rats showed a disruption in temporal learning in late symptomatic animals. Age-related modification in stress-induced impairment of temporal control of behavior was also observed, an effect which was greatly reduced in BACHD animals, thus confirming previous results suggesting reduced emotional reactivity in HD animals. The results suggest a staggered onset in cognitive

  10. Elucidating dynamic metabolic physiology through network integration of quantitative time-course metabolomics

    DEFF Research Database (Denmark)

    Bordbar, Aarash; Yurkovich, James T.; Paglia, Giuseppe

    2017-01-01

    The increasing availability of metabolomics data necessitates novel methods for deeper data analysis and interpretation. We present a flux balance analysis method that allows for the computation of dynamic intracellular metabolic changes at the cellular scale through integration of time-course ab......The increasing availability of metabolomics data necessitates novel methods for deeper data analysis and interpretation. We present a flux balance analysis method that allows for the computation of dynamic intracellular metabolic changes at the cellular scale through integration of time...

  11. Optimal parallel algorithms for problems modeled by a family of intervals

    Science.gov (United States)

    Olariu, Stephan; Schwing, James L.; Zhang, Jingyuan

    1992-01-01

    A family of intervals on the real line provides a natural model for a vast number of scheduling and VLSI problems. Recently, a number of parallel algorithms to solve a variety of practical problems on such a family of intervals have been proposed in the literature. Computational tools are developed, and it is shown how they can be used for the purpose of devising cost-optimal parallel algorithms for a number of interval-related problems including finding a largest subset of pairwise nonoverlapping intervals, a minimum dominating subset of intervals, along with algorithms to compute the shortest path between a pair of intervals and, based on the shortest path, a parallel algorithm to find the center of the family of intervals. More precisely, with an arbitrary family of n intervals as input, all algorithms run in O(log n) time using O(n) processors in the EREW-PRAM model of computation.

  12. Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection

    NARCIS (Netherlands)

    Tarana, A.; Belloni, T.; Bazzano, A.; Mendez, M.; Ubertini, P.

    We report results of a one-year monitoring of the low-mass X-ray binary (LMXB) source (atoll type) 4U 1728-34 with INTEGRAL and RXTE. Three time intervals were covered by INTEGRAL, during which the source showed strong spectral evolution. We studied the broad-band X-ray spectra in detail by fitting

  13. Synchronization of Switched Interval Networks and Applications to Chaotic Neural Networks

    Directory of Open Access Journals (Sweden)

    Jinde Cao

    2013-01-01

    Full Text Available This paper investigates synchronization problem of switched delay networks with interval parameters uncertainty, based on the theories of the switched systems and drive-response technique, a mathematical model of the switched interval drive-response error system is established. Without constructing Lyapunov-Krasovskii functions, introducing matrix measure method for the first time to switched time-varying delay networks, combining Halanay inequality technique, synchronization criteria are derived for switched interval networks under the arbitrary switching rule, which are easy to verify in practice. Moreover, as an application, the proposed scheme is then applied to chaotic neural networks. Finally, numerical simulations are provided to illustrate the effectiveness of the theoretical results.

  14. Effect of Remote Back-Up Protection System Failure on the Optimum Routine Test Time Interval of Power System Protection

    Directory of Open Access Journals (Sweden)

    Y Damchi

    2013-12-01

    Full Text Available Appropriate operation of protection system is one of the effective factors to have a desirable reliability in power systems, which vitally needs routine test of protection system. Precise determination of optimum routine test time interval (ORTTI plays a vital role in predicting the maintenance costs of protection system. In the most previous studies, ORTTI has been determined while remote back-up protection system was considered fully reliable. This assumption is not exactly correct since remote back-up protection system may operate incorrectly or fail to operate, the same as the primary protection system. Therefore, in order to determine the ORTTI, an extended Markov model is proposed in this paper considering failure probability for remote back-up protection system. In the proposed Markov model of the protection systems, monitoring facility is taken into account. Moreover, it is assumed that the primary and back-up protection systems are maintained simultaneously. Results show that the effect of remote back-up protection system failures on the reliability indices and optimum routine test intervals of protection system is considerable.

  15. Effects of computing time delay on real-time control systems

    Science.gov (United States)

    Shin, Kang G.; Cui, Xianzhong

    1988-01-01

    The reliability of a real-time digital control system depends not only on the reliability of the hardware and software used, but also on the speed in executing control algorithms. The latter is due to the negative effects of computing time delay on control system performance. For a given sampling interval, the effects of computing time delay are classified into the delay problem and the loss problem. Analysis of these two problems is presented as a means of evaluating real-time control systems. As an example, both the self-tuning predicted (STP) control and Proportional-Integral-Derivative (PID) control are applied to the problem of tracking robot trajectories, and their respective effects of computing time delay on control performance are comparatively evaluated. For this example, the STP (PID) controller is shown to outperform the PID (STP) controller in coping with the delay (loss) problem.

  16. Model-based Integration of Past & Future in TimeTravel

    DEFF Research Database (Denmark)

    Khalefa, Mohamed E.; Fischer, Ulrike; Pedersen, Torben Bach

    2012-01-01

    We demonstrate TimeTravel, an efficient DBMS system for seamless integrated querying of past and (forecasted) future values of time series, allowing the user to view past and future values as one joint time series. This functionality is important for advanced application domain like energy....... The main idea is to compactly represent time series as models. By using models, the TimeTravel system answers queries approximately on past and future data with error guarantees (absolute error and confidence) one order of magnitude faster than when accessing the time series directly. In addition...... it to answer approximate and exact queries. TimeTravel is implemented into PostgreSQL, thus achieving complete user transparency at the query level. In the demo, we show the easy building of a hierarchical model index for a real-world time series and the effect of varying the error guarantees on the speed up...

  17. Time-independent integral equation for Maxwell's system. Application of radar cross section computation

    International Nuclear Information System (INIS)

    Pujols, Agnes

    1991-01-01

    We prove that the scattering operator for the wave equation in the exterior of an non-homogeneous obstacle exists. Its distribution kernel is represented by a time-dependent boundary integral equation. A space-time integral variational formulation is developed for determining the current induced by the scattering of an electromagnetic wave by an homogeneous object. The discrete approximation of the variational problem using a finite element method in both space and time leads to stable convergent schemes, giving a numerical code for perfectly conducting cylinders. (author) [fr

  18. Permanently calibrated interpolating time counter

    International Nuclear Information System (INIS)

    Jachna, Z; Szplet, R; Kwiatkowski, P; Różyc, K

    2015-01-01

    We propose a new architecture of an integrated time interval counter that provides its permanent calibration in the background. Time interval measurement and the calibration procedure are based on the use of a two-stage interpolation method and parallel processing of measurement and calibration data. The parallel processing is achieved by a doubling of two-stage interpolators in measurement channels of the counter, and by an appropriate extension of control logic. Such modification allows the updating of transfer characteristics of interpolators without the need to break a theoretically infinite measurement session. We describe the principle of permanent calibration, its implementation and influence on the quality of the counter. The precision of the presented counter is kept at a constant level (below 20 ps) despite significant changes in the ambient temperature (from −10 to 60 °C), which can cause a sevenfold decrease in the precision of the counter with a traditional calibration procedure. (paper)

  19. Interval-valued intuitionistic fuzzy multi-criteria model for design concept selection

    Directory of Open Access Journals (Sweden)

    Daniel Osezua Aikhuele

    2017-09-01

    Full Text Available This paper presents a new approach for design concept selection by using an integrated Fuzzy Analytical Hierarchy Process (FAHP and an Interval-valued intuitionistic fuzzy modified TOP-SIS (IVIF-modified TOPSIS model. The integrated model which uses the improved score func-tion and a weighted normalized Euclidean distance method for the calculation of the separation measures of alternatives from the positive and negative intuitionistic ideal solutions provides a new approach for the computation of intuitionistic fuzzy ideal solutions. The results of the two approaches are integrated using a reflection defuzzification integration formula. To ensure the feasibility and the rationality of the integrated model, the method is successfully applied for eval-uating and selecting some design related problems including a real-life case study for the selec-tion of the best concept design for a new printed-circuit-board (PCB and for a hypothetical ex-ample. The model which provides a novel alternative, has been compared with similar computa-tional methods in the literature.

  20. Hybrid state-space time integration of rotating beams

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2012-01-01

    An efficient time integration algorithm for the dynamic equations of flexible beams in a rotating frame of reference is presented. The equations of motion are formulated in a hybrid state-space format in terms of local displacements and local components of the absolute velocity. With inspiration...... of the system rotation enter via global operations with the angular velocity vector. The algorithm is based on an integrated form of the equations of motion with energy and momentum conserving properties, if a kinematically consistent non-linear formulation is used. A consistent monotonic scheme for algorithmic...... energy dissipation in terms of local displacements and velocities, typical of structural vibrations, is developed and implemented in the form of forward weighting of appropriate mean value terms in the algorithm. The algorithm is implemented for a beam theory with consistent quadratic non...

  1. Birth interval and its predictors among married women in Dabat ...

    African Journals Online (AJOL)

    2008-12-30

    Birth intervals (time between two successive live births) if short are associated with diverse complications. We assessed birth interval and its predictors among 613 married women who gave birth from January 1 to December 30, 2008. Data were collected in April 2012. Life table and Kaplan-Meier curve were used to ...

  2. Integral Time and the Varieties of Post-Mortem Survival

    Directory of Open Access Journals (Sweden)

    Sean M. Kelly

    2008-06-01

    Full Text Available While the question of survival of bodily death is usually approached by focusing on the mind/body relation (and often with the idea of the soul as a special kind of substance, this paper explores the issue in the context of our understanding of time. The argument of the paper is woven around the central intuition of time as an “ever-living present.” The development of this intuition allows for a more integral or “complex-holistic” theory of time, the soul, and the question of survival. Following the introductory matter, the first section proposes a re-interpretation of Nietzsche’s doctrine of eternal recurrence in terms of moments and lives as “eternally occurring.” The next section is a treatment of Julian Barbour’s neo-Machian model of instants of time as configurations in the n-dimensional phase-space he calls “Platonia.” While rejecting his claim to have done away with time, I do find his model suggestive of the idea of moments and lives as eternally occurring. The following section begins with Fechner’s visionary ideas of the nature of the soul and its survival of bodily death, with particular attention to the notion of holonic inclusion and the central analogy of the transition from perception to memory. I turn next to Whitehead’s equally holonic notions of prehension and the concrescence of actual occasions. From his epochal theory of time and certain ambiguities in his reflections on the “divine antinomies,” we are brought to the threshold of a potentially more integral or “complex-holistic” theory of time and survival, which is treated in the last section. This section draws from my earlier work on Hegel, Jung, and Edgar Morin, as well as from key insights of Jean Gebser, for an interpretation of Sri Aurobindo’s inspired but cryptic description of the “Supramental Time Vision.” This interpretation leads to an alternative understanding of reincarnation—and to the possibility of its reconciliation

  3. Connection between Feynman integrals having different values of the space-time dimension

    International Nuclear Information System (INIS)

    Tarasov, O.V.

    1996-05-01

    A systematic algorithm for obtaining recurrence relations for dimensionally regularized Feynman integrals w.r.t. the space-time dimension d is proposed. The relation between d and d-2 dimensional integrals is given in terms of a differential operator for which an explicit formula can be obtained for each Feynman diagram. We show how the method works for one-, two- and three-loop integrals. The new recurrence relations w.r.t. d are complementary to the recurrence relations which derive from the method of integration by parts. We find that the problem of the irreducible numerators in Feynman integrals can be naturally solved in the framework of the proposed generalized recurrence relations. (orig.)

  4. Prospects for direct measurement of time-integrated Bs mixing

    International Nuclear Information System (INIS)

    Siccama, I.

    1994-01-01

    This note investigates the prospects of measuring time-integrated B s mixing. Three inclusive decay modes of the B s meson are discussed. For each reconstruction mode, the expected number of events and the different background channels are discussed. Estimates are given for the uncertainty on the mixing parameter χ s . (orig.)

  5. Evaluation of the filtered leapfrog-trapezoidal time integration method

    International Nuclear Information System (INIS)

    Roache, P.J.; Dietrich, D.E.

    1988-01-01

    An analysis and evaluation are presented for a new method of time integration for fluid dynamic proposed by Dietrich. The method, called the filtered leapfrog-trapezoidal (FLT) scheme, is analyzed for the one-dimensional constant-coefficient advection equation and is shown to have some advantages for quasi-steady flows. A modification (FLTW) using a weighted combination of FLT and leapfrog is developed which retains the advantages for steady flows, increases accuracy for time-dependent flows, and involves little coding effort. Merits and applicability are discussed

  6. On interval and cyclic interval edge colorings of (3,5)-biregular graphs

    DEFF Research Database (Denmark)

    Casselgren, Carl Johan; Petrosyan, Petros; Toft, Bjarne

    2017-01-01

    A proper edge coloring f of a graph G with colors 1,2,3,…,t is called an interval coloring if the colors on the edges incident to every vertex of G form an interval of integers. The coloring f is cyclic interval if for every vertex v of G, the colors on the edges incident to v either form an inte...

  7. An extended Halanay inequality of integral type on time scales

    Directory of Open Access Journals (Sweden)

    Boqun Ou

    2015-07-01

    Full Text Available In this paper, we obtain a Halanay-type inequality of integral type on time scales which improves and extends some earlier results for both the continuous and discrete cases. Several illustrative examples are also given.

  8. Heat Generation on Implant Surface During Abutment Preparation at Different Elapsed Time Intervals.

    Science.gov (United States)

    Al-Keraidis, Abdullah; Aleisa, Khalil; Al-Dwairi, Ziad Nawaf; Al-Tahawi, Hamdi; Hsu, Ming-Lun; Lynch, Edward; Özcan, Mutlu

    2017-10-01

    The purpose of this study was to evaluate heat generation at the implant surface caused by abutment preparation using a diamond bur in a high-speed dental turbine in vitro at 2 different water-coolant temperatures. Thirty-two titanium-alloy abutments were connected to a titanium-alloy implant embedded in an acrylic resin placed within a water bath at a controlled temperature of 37°C. The specimens were equally distributed into 2 groups (16 each). Group 1: the temperature was maintained at 20 ± 1°C; and group 2: the temperature was maintained at 32 ± 1°C. Each abutment was prepared in the axial plane for 1 minute and in the occlusal plane for 1 minute. The temperature of the heat generated from abutment preparation was recorded and measured at 3 distinct time intervals. Water-coolant temperature (20°C vs 32°C) had a statistically significant effect on the implant's temperature change during preparation of the abutment (P water-coolant temperature of 20 ± 1°C during preparation of the implant abutment decreased the temperature recorded at the implant surface to 34.46°C, whereas the coolant temperature of 32 ± 1°C increased the implant surface temperature to 40.94°C.

  9. INTERVAL STATE ESTIMATION FOR SINGULAR DIFFERENTIAL EQUATION SYSTEMS WITH DELAYS

    Directory of Open Access Journals (Sweden)

    T. A. Kharkovskaia

    2016-07-01

    Full Text Available The paper deals with linear differential equation systems with algebraic restrictions (singular systems and a method of interval observer design for this kind of systems. The systems contain constant time delay, measurement noise and disturbances. Interval observer synthesis is based on monotone and cooperative systems technique, linear matrix inequations, Lyapunov function theory and interval arithmetic. The set of conditions that gives the possibility for interval observer synthesis is proposed. Results of synthesized observer operation are shown on the example of dynamical interindustry balance model. The advantages of proposed method are that it is adapted to observer design for uncertain systems, if the intervals of admissible values for uncertain parameters are given. The designed observer is capable to provide asymptotically definite limits on the estimation accuracy, since the interval of admissible values for the object state is defined at every instant. The obtained result provides an opportunity to develop the interval estimation theory for complex systems that contain parametric uncertainty, varying delay and nonlinear elements. Interval observers increasingly find applications in economics, electrical engineering, mechanical systems with constraints and optimal flow control.

  10. Hybrid neuro-heuristic methodology for simulation and control of dynamic systems over time interval.

    Science.gov (United States)

    Woźniak, Marcin; Połap, Dawid

    2017-09-01

    Simulation and positioning are very important aspects of computer aided engineering. To process these two, we can apply traditional methods or intelligent techniques. The difference between them is in the way they process information. In the first case, to simulate an object in a particular state of action, we need to perform an entire process to read values of parameters. It is not very convenient for objects for which simulation takes a long time, i.e. when mathematical calculations are complicated. In the second case, an intelligent solution can efficiently help on devoted way of simulation, which enables us to simulate the object only in a situation that is necessary for a development process. We would like to present research results on developed intelligent simulation and control model of electric drive engine vehicle. For a dedicated simulation method based on intelligent computation, where evolutionary strategy is simulating the states of the dynamic model, an intelligent system based on devoted neural network is introduced to control co-working modules while motion is in time interval. Presented experimental results show implemented solution in situation when a vehicle transports things over area with many obstacles, what provokes sudden changes in stability that may lead to destruction of load. Therefore, applied neural network controller prevents the load from destruction by positioning characteristics like pressure, acceleration, and stiffness voltage to absorb the adverse changes of the ground. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Time-Varying Market Integration and Expected Returns in Emerging Markets

    OpenAIRE

    de Jong, Frank; de Roon, Frans

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market. The level of integration is a time-varying variable that depends on the market value of the assets that can be held by domestic investors only versus the market value of the assets that can be traded freely. Our empirical analysis for 30 emerging markets shows that there are stro...

  12. Time Varying Market Integration and Expected Rteurns in Emerging Markets

    OpenAIRE

    Jong, F.C.J.M. de; Roon, F.A. de

    2001-01-01

    We use a simple model in which the expected returns in emerging markets depend on their systematic risk as measured by their beta relative to the world portfolio as well as on the level of integration in that market.The level of integration is a time-varying variable that depends on the market value of the assets that can be held by domestic investors only versus the market value of the assets that can be traded freely.Our empirical analysis for 30 emerging markets shows that there are strong...

  13. Constraint-based Attribute and Interval Planning

    Science.gov (United States)

    Jonsson, Ari; Frank, Jeremy

    2013-01-01

    In this paper we describe Constraint-based Attribute and Interval Planning (CAIP), a paradigm for representing and reasoning about plans. The paradigm enables the description of planning domains with time, resources, concurrent activities, mutual exclusions among sets of activities, disjunctive preconditions and conditional effects. We provide a theoretical foundation for the paradigm, based on temporal intervals and attributes. We then show how the plans are naturally expressed by networks of constraints, and show that the process of planning maps directly to dynamic constraint reasoning. In addition, we de ne compatibilities, a compact mechanism for describing planning domains. We describe how this framework can incorporate the use of constraint reasoning technology to improve planning. Finally, we describe EUROPA, an implementation of the CAIP framework.

  14. The Geomagnetic Field Recorded in Sediments of the Tuzla Section (the Krasnodar Territory, Russia) over the Time Interval 120-70 ka

    DEFF Research Database (Denmark)

    Pilipenko, Olga; Abrahamsen, N.; Trubikhin, V. M.

    2007-01-01

    Petro- and paleomagnetic methods are applied to the study of the lower part of the Early Pleistocene Tuzla section on the Black Sea coast of the Taman Peninsula. This part of the section is composed of marine and lagoonal sediments deposited over the time interval 120-70 ka. The measured curves...... of the variation in the geomagnetic field inclination reveal an anomalous direction dated at ~110 ka which coincides with a similar anomalous direction in the Eltigen section (Ukraine) correlating with the Blake paleomagnetic event. The significant correlation between the time series NRM0.015/SIRM0.015 (Tuzla...

  15. Late recovery of damage in rat spinal cord and bone marrow observed in split dose irradiation with long time intervals for 300 kV X-rays and 15 MeV neutrons

    International Nuclear Information System (INIS)

    Kogel, A.J. van der; Sissingh, H.A.

    The authors have performed an extended study on the capacity of the spinal cord for recovery of damage over long time intervals in split-dose experiments with 300 kV X-rays and 15 MeV neutrons, with time intervals of up to 30 weeks. The dose-response relationships for long term bone marrow depletion have been analysed and compared with those obtained for acute and late spinal cord damage. (Auth.)

  16. Extending molecular simulation time scales: Parallel in time integrations for high-level quantum chemistry and complex force representations

    International Nuclear Information System (INIS)

    Bylaska, Eric J.; Weare, Jonathan Q.; Weare, John H.

    2013-01-01

    Parallel in time simulation algorithms are presented and applied to conventional molecular dynamics (MD) and ab initio molecular dynamics (AIMD) models of realistic complexity. Assuming that a forward time integrator, f (e.g., Verlet algorithm), is available to propagate the system from time t i (trajectory positions and velocities x i = (r i , v i )) to time t i+1 (x i+1 ) by x i+1 = f i (x i ), the dynamics problem spanning an interval from t 0 …t M can be transformed into a root finding problem, F(X) = [x i − f(x (i−1 )] i =1,M = 0, for the trajectory variables. The root finding problem is solved using a variety of root finding techniques, including quasi-Newton and preconditioned quasi-Newton schemes that are all unconditionally convergent. The algorithms are parallelized by assigning a processor to each time-step entry in the columns of F(X). The relation of this approach to other recently proposed parallel in time methods is discussed, and the effectiveness of various approaches to solving the root finding problem is tested. We demonstrate that more efficient dynamical models based on simplified interactions or coarsening time-steps provide preconditioners for the root finding problem. However, for MD and AIMD simulations, such preconditioners are not required to obtain reasonable convergence and their cost must be considered in the performance of the algorithm. The parallel in time algorithms developed are tested by applying them to MD and AIMD simulations of size and complexity similar to those encountered in present day applications. These include a 1000 Si atom MD simulation using Stillinger-Weber potentials, and a HCl + 4H 2 O AIMD simulation at the MP2 level. The maximum speedup ((serial execution time)/(parallel execution time) ) obtained by parallelizing the Stillinger-Weber MD simulation was nearly 3.0. For the AIMD MP2 simulations, the algorithms achieved speedups of up to 14.3. The parallel in time algorithms can be implemented in a

  17. ePRISM: A case study in multiple proxy and mixed temporal resolution integration

    Science.gov (United States)

    Robinson, Marci M.; Dowsett, Harry J.

    2010-01-01

    As part of the Pliocene Research, Interpretation and Synoptic Mapping (PRISM) Project, we present the ePRISM experiment designed I) to provide climate modelers with a reconstruction of an early Pliocene warm period that was warmer than the PRISM interval (similar to 3.3 to 3.0 Ma), yet still similar in many ways to modern conditions and 2) to provide an example of how best to integrate multiple-proxy sea surface temperature (SST) data from time series with varying degrees of temporal resolution and age control as we begin to build the next generation of PRISM, the PRISM4 reconstruction, spanning a constricted time interval. While it is possible to tie individual SST estimates to a single light (warm) oxygen isotope event, we find that the warm peak average of SST estimates over a narrowed time interval is preferential for paleoclimate reconstruction as it allows for the inclusion of more records of multiple paleotemperature proxies.

  18. Circadian profile of QT interval and QT interval variability in 172 healthy volunteers

    DEFF Research Database (Denmark)

    Bonnemeier, Hendrik; Wiegand, Uwe K H; Braasch, Wiebke

    2003-01-01

    of sleep. QT and R-R intervals revealed a characteristic day-night-pattern. Diurnal profiles of QT interval variability exhibited a significant increase in the morning hours (6-9 AM; P ... lower at day- and nighttime. Aging was associated with an increase of QT interval mainly at daytime and a significant shift of the T wave apex towards the end of the T wave. The circadian profile of ventricular repolarization is strongly related to the mean R-R interval, however, there are significant...

  19. A Novel Finite-Sum Inequality-Based Method for Robust H∞ Control of Uncertain Discrete-Time Takagi-Sugeno Fuzzy Systems With Interval-Like Time-Varying Delays.

    Science.gov (United States)

    Zhang, Xian-Ming; Han, Qing-Long; Ge, Xiaohua

    2017-09-22

    This paper is concerned with the problem of robust H∞ control of an uncertain discrete-time Takagi-Sugeno fuzzy system with an interval-like time-varying delay. A novel finite-sum inequality-based method is proposed to provide a tighter estimation on the forward difference of certain Lyapunov functional, leading to a less conservative result. First, an auxiliary vector function is used to establish two finite-sum inequalities, which can produce tighter bounds for the finite-sum terms appearing in the forward difference of the Lyapunov functional. Second, a matrix-based quadratic convex approach is employed to equivalently convert the original matrix inequality including a quadratic polynomial on the time-varying delay into two boundary matrix inequalities, which delivers a less conservative bounded real lemma (BRL) for the resultant closed-loop system. Third, based on the BRL, a novel sufficient condition on the existence of suitable robust H∞ fuzzy controllers is derived. Finally, two numerical examples and a computer-simulated truck-trailer system are provided to show the effectiveness of the obtained results.

  20. Long-time integrator for the study on plasma parameter fluctuations

    International Nuclear Information System (INIS)

    Zalkind, V.M.; Tarasenko, V.P.

    1975-01-01

    A device measuring the absolute value (x) of a fluctuating quantity x(t) averaged over a large number of realizations is described. The specific features of the device are the use of the time selector (Δ t = 50 μs - 1 ms) and the large time integration constant (tau = 30 hrs). The device is meant for studying fluctuations of parameters of a pulse plasma with a small repetition frequency

  1. Molecular radiotherapy: the NUKFIT software for calculating the time-integrated activity coefficient.

    Science.gov (United States)

    Kletting, P; Schimmel, S; Kestler, H A; Hänscheid, H; Luster, M; Fernández, M; Bröer, J H; Nosske, D; Lassmann, M; Glatting, G

    2013-10-01

    Calculation of the time-integrated activity coefficient (residence time) is a crucial step in dosimetry for molecular radiotherapy. However, available software is deficient in that it is either not tailored for the use in molecular radiotherapy and/or does not include all required estimation methods. The aim of this work was therefore the development and programming of an algorithm which allows for an objective and reproducible determination of the time-integrated activity coefficient and its standard error. The algorithm includes the selection of a set of fitting functions from predefined sums of exponentials and the choice of an error model for the used data. To estimate the values of the adjustable parameters an objective function, depending on the data, the parameters of the error model, the fitting function and (if required and available) Bayesian information, is minimized. To increase reproducibility and user-friendliness the starting values are automatically determined using a combination of curve stripping and random search. Visual inspection, the coefficient of determination, the standard error of the fitted parameters, and the correlation matrix are provided to evaluate the quality of the fit. The functions which are most supported by the data are determined using the corrected Akaike information criterion. The time-integrated activity coefficient is estimated by analytically integrating the fitted functions. Its standard error is determined assuming Gaussian error propagation. The software was implemented using MATLAB. To validate the proper implementation of the objective function and the fit functions, the results of NUKFIT and SAAM numerical, a commercially available software tool, were compared. The automatic search for starting values was successfully tested for reproducibility. The quality criteria applied in conjunction with the Akaike information criterion allowed the selection of suitable functions. Function fit parameters and their standard

  2. SEMIGROUPS N TIMES INTEGRATED AND AN APPLICATION TO A PROBLEM OF CAUCHY TYPE

    Directory of Open Access Journals (Sweden)

    Danessa Chirinos Fernández

    2016-06-01

    Full Text Available The theory of semigroups n times integrated is a generalization of strongly continuous semigroups, which was developed from 1984, and is widely used for the study of the existence and uniqueness of problems such Cauchy in which the operator domain is not necessarily dense. This paper presents an application of semigroups n times integrated into a problem of viscoelasticity, which is formulated as a Cauchy problem on a Banach space presents .

  3. Extending molecular simulation time scales: Parallel in time integrations for high-level quantum chemistry and complex force representations.

    Science.gov (United States)

    Bylaska, Eric J; Weare, Jonathan Q; Weare, John H

    2013-08-21

    Parallel in time simulation algorithms are presented and applied to conventional molecular dynamics (MD) and ab initio molecular dynamics (AIMD) models of realistic complexity. Assuming that a forward time integrator, f (e.g., Verlet algorithm), is available to propagate the system from time ti (trajectory positions and velocities xi = (ri, vi)) to time ti + 1 (xi + 1) by xi + 1 = fi(xi), the dynamics problem spanning an interval from t0[ellipsis (horizontal)]tM can be transformed into a root finding problem, F(X) = [xi - f(x(i - 1)]i = 1, M = 0, for the trajectory variables. The root finding problem is solved using a variety of root finding techniques, including quasi-Newton and preconditioned quasi-Newton schemes that are all unconditionally convergent. The algorithms are parallelized by assigning a processor to each time-step entry in the columns of F(X). The relation of this approach to other recently proposed parallel in time methods is discussed, and the effectiveness of various approaches to solving the root finding problem is tested. We demonstrate that more efficient dynamical models based on simplified interactions or coarsening time-steps provide preconditioners for the root finding problem. However, for MD and AIMD simulations, such preconditioners are not required to obtain reasonable convergence and their cost must be considered in the performance of the algorithm. The parallel in time algorithms developed are tested by applying them to MD and AIMD simulations of size and complexity similar to those encountered in present day applications. These include a 1000 Si atom MD simulation using Stillinger-Weber potentials, and a HCl + 4H2O AIMD simulation at the MP2 level. The maximum speedup (serial execution/timeparallel execution time) obtained by parallelizing the Stillinger-Weber MD simulation was nearly 3.0. For the AIMD MP2 simulations, the algorithms achieved speedups of up to 14.3. The parallel in time algorithms can be implemented in a

  4. Modified stochastic fragmentation of an interval as an ageing process

    Science.gov (United States)

    Fortin, Jean-Yves

    2018-02-01

    We study a stochastic model based on modified fragmentation of a finite interval. The mechanism consists of cutting the interval at a random location and substituting a unique fragment on the right of the cut to regenerate and preserve the interval length. This leads to a set of segments of random sizes, with the accumulation of small fragments near the origin. This model is an example of record dynamics, with the presence of ‘quakes’ and slow dynamics. The fragment size distribution is a universal inverse power law with logarithmic corrections. The exact distribution for the fragment number as function of time is simply related to the unsigned Stirling numbers of the first kind. Two-time correlation functions are defined, and computed exactly. They satisfy scaling relations, and exhibit aging phenomena. In particular, the probability that the same number of fragments is found at two different times t>s is asymptotically equal to [4πlog(s)]-1/2 when s\\gg 1 and the ratio t/s is fixed, in agreement with the numerical simulations. The same process with a reset impedes the aging phenomenon-beyond a typical time scale defined by the reset parameter.

  5. Dissociation of the role of the prelimbic cortex in interval timing and resource allocation: beneficial effect of norepinephrine and dopamine reuptake inhibitor nomifensine on anxiety-inducing distraction

    Directory of Open Access Journals (Sweden)

    Alexander R Matthews

    2012-12-01

    Full Text Available Emotional distracters impair cognitive function. Emotional processing is dysregulated in affective disorders such as depression, phobias, schizophrenia, and PTSD. Among the processes impaired by emotional distracters, and whose dysregulation is documented in affective disorders, is the ability to time in the seconds-to-minutes range, i.e. interval timing. Presentation of task-irrelevant distracters during a timing task results in a delay in responding suggesting a failure to maintain subjective time in working memory, possibly due to attentional and working memory resources being diverted away from timing, as proposed by the Relative Time-Sharing model. We investigated the role of the prelimbic cortex in the detrimental effect of anxiety-inducing task-irrelevant distracters on the cognitive ability to keep track of time, using local infusions of norepinephrine and dopamine reuptake inhibitor nomifensine in a modified peak-interval procedure with neutral and anxiety-inducing distracters. Given that some antidepressants have beneficial effects on attention and working memory, e.g., decreasing emotional response to negative events, we hypothesized that nomifensine would improve maintenance of information in working memory in trials with distracters, resulting in a decrease of the disruptive effect of emotional events on the timekeeping abilities. Our results revealed a dissociation of the effects of nomifensine infusion in prelimbic cortex between interval timing and resource allocation, and between neutral and anxiety-inducing distraction. Nomifensine was effective only during trials with distracters, but not during trials without distracters. Nomifensine reduced the detrimental effect of the distracters only when the distracters were anxiety-inducing, but not when they were neutral. Results are discussed in relation to the brain circuits involved in Relative Time-Sharing of resources, and the pharmacological management of affective disorders.

  6. Towards a portable microchip system with integrated thermal control and polymer waveguides for real-time PCR

    DEFF Research Database (Denmark)

    Wang, Zhenyu; Sekulovic, Andrea; Kutter, Jörg Peter

    2006-01-01

    A novel real-time PCR microchip platform with integrated thermal system and polymer waveguides has been developed. The integrated polymer optical system for real-time monitoring of PCR was fabricated in the same SU-8 layer as the PCR chamber, without additional masking steps. Two suitable DNA...... binding dyes, SYTOX Orange and TO-PRO-3, were selected and tested for the real-time PCR processes. As a model, cadF gene of Campylobacter jejuni has been amplified on the microchip. Using the integrated optical system of the real-time PCR microchip, the measured cycle threshold values of the real-time PCR...

  7. On the initial condition problem of the time domain PMCHWT surface integral equation

    KAUST Repository

    Uysal, Ismail Enes; Bagci, Hakan; Ergin, A. Arif; Ulku, H. Arda

    2017-01-01

    Non-physical, linearly increasing and constant current components are induced in marching on-in-time solution of time domain surface integral equations when initial conditions on time derivatives of (unknown) equivalent currents are not enforced

  8. Diagnostic interval and mortality in colorectal cancer

    DEFF Research Database (Denmark)

    Tørring, Marie Louise; Frydenberg, Morten; Hamilton, William

    2012-01-01

    Objective To test the theory of a U-shaped association between time from the first presentation of symptoms in primary care to the diagnosis (the diagnostic interval) and mortality after diagnosis of colorectal cancer (CRC). Study Design and Setting Three population-based studies in Denmark...

  9. High-intensity interval training improves VO2peak, maximal lactate accumulation, time trial and competition performance in 9?11-year-old swimmers

    OpenAIRE

    Sperlich, Billy; Zinner, Christoph; Heilemann, Ilka; Kjendlie, Per-Ludvik; Holmberg, Hans-Christer; Mester, Joachim

    2010-01-01

    Training volume in swimming is usually very high when compared to the relatively short competition time. High-intensity interval training (HIIT) has been demonstrated to improve performance in a relatively short training period. The main purpose of the present study was to examine the effects of a 5-week HIIT versus high-volume training (HVT) in 9?11-year-old swimmers on competition performance, 100 and 2,000?m time (T 100?m and T 2,000?m), VO2peak and rate of maximal lactate accumulation (La...

  10. Modular 125 ps resolution time interval digitizer for 10 MHz stop burst rates and 33 ms range

    International Nuclear Information System (INIS)

    Turko, B.

    1978-01-01

    A high resolution multiple stop time interval digitizer is described. It is capable of resolving stop burst rates of up to 10 MHz with an incremental resolution of 125 ps within a range of 33 ms. The digitizer consists of five CAMAC modules and uses a standard CAMAC crate and controller. All the functions and ranges are completely computer controlled. Any two subsequent stop pulses in a burst can be resolved within 100 ns due to a new dual interpolation technique employed. The accuracy is maintained by a high stability 125 MHz reference clock. Up to 131 stop events can be stored in a 48-bit, 10 MHz derandomizing storage register before the digitizer overflows. The experimental data are also given

  11. Integration of Simulink, MARTe and MDSplus for rapid development of real-time applications

    Energy Technology Data Exchange (ETDEWEB)

    Manduchi, G., E-mail: gabriele.manduchi@igi.cnr.it [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova (Italy); Luchetta, A.; Taliercio, C. [Consorzio RFX (CNR, ENEA, INFN, Università di Padova, Acciaierie Venete SpA), Padova (Italy); Neto, A.; Sartori, F. [Fusion for Energy, Barcelona (Spain); De Tommasi, G. [Fusion for Energy, Barcelona (Spain); Consorzio CREATE/DIETI, Università degli Studi di Napoli Federico II, Via Claudio 21, 80125 Napoli (Italy)

    2015-10-15

    Highlights: • The integration of two frameworks for real-time control and data acquisition is described. • The integration may significantly fasten the development of system components. • The system includes also a code generator for the integration of code written in Simulink. • A real-time control systemcan be implemented without the need of writing any line of code. - Abstract: Simulink is a graphical data flow programming tool for modeling and simulating dynamic systems. A component of Simulink, called Simulink Coder, generates C code from Simulink diagrams. MARTe is a framework for the implementation of real-time systems, currently in use in several fusion experiments. MDSplus is a framework widely used in the fusion community for the management of data. The three systems provide a solution to different facets of the same process, that is, real-time plasma control development. Simulink diagrams will describe the algorithms used in control, which will be implemented as MARTe GAMs and which will use parameters read from and produce results written to MDSplus pulse files. The three systems have been integrated in order to provide a tool suitable to speed up the development of real-time control applications. In particular, it will be shown how from a Simulink diagram describing a given algorithm to be used in a control system, it is possible to generate in an automated way the corresponding MARTe and MDSplus components that can be assembled to implement the target system.

  12. Integration of Simulink, MARTe and MDSplus for rapid development of real-time applications

    International Nuclear Information System (INIS)

    Manduchi, G.; Luchetta, A.; Taliercio, C.; Neto, A.; Sartori, F.; De Tommasi, G.

    2015-01-01

    Highlights: • The integration of two frameworks for real-time control and data acquisition is described. • The integration may significantly fasten the development of system components. • The system includes also a code generator for the integration of code written in Simulink. • A real-time control systemcan be implemented without the need of writing any line of code. - Abstract: Simulink is a graphical data flow programming tool for modeling and simulating dynamic systems. A component of Simulink, called Simulink Coder, generates C code from Simulink diagrams. MARTe is a framework for the implementation of real-time systems, currently in use in several fusion experiments. MDSplus is a framework widely used in the fusion community for the management of data. The three systems provide a solution to different facets of the same process, that is, real-time plasma control development. Simulink diagrams will describe the algorithms used in control, which will be implemented as MARTe GAMs and which will use parameters read from and produce results written to MDSplus pulse files. The three systems have been integrated in order to provide a tool suitable to speed up the development of real-time control applications. In particular, it will be shown how from a Simulink diagram describing a given algorithm to be used in a control system, it is possible to generate in an automated way the corresponding MARTe and MDSplus components that can be assembled to implement the target system.

  13. Multifactor analysis of multiscaling in volatility return intervals.

    Science.gov (United States)

    Wang, Fengzhong; Yamasaki, Kazuko; Havlin, Shlomo; Stanley, H Eugene

    2009-01-01

    We study the volatility time series of 1137 most traded stocks in the U.S. stock markets for the two-year period 2001-2002 and analyze their return intervals tau , which are time intervals between volatilities above a given threshold q . We explore the probability density function of tau , P_(q)(tau) , assuming a stretched exponential function, P_(q)(tau) approximately e;(-tau;(gamma)) . We find that the exponent gamma depends on the threshold in the range between q=1 and 6 standard deviations of the volatility. This finding supports the multiscaling nature of the return interval distribution. To better understand the multiscaling origin, we study how gamma depends on four essential factors, capitalization, risk, number of trades, and return. We show that gamma depends on the capitalization, risk, and return but almost does not depend on the number of trades. This suggests that gamma relates to the portfolio selection but not on the market activity. To further characterize the multiscaling of individual stocks, we fit the moments of tau , mu_(m) identical with(tautau);(m);(1m) , in the range of 10portfolio optimization.

  14. Multifactor analysis of multiscaling in volatility return intervals

    Science.gov (United States)

    Wang, Fengzhong; Yamasaki, Kazuko; Havlin, Shlomo; Stanley, H. Eugene

    2009-01-01

    We study the volatility time series of 1137 most traded stocks in the U.S. stock markets for the two-year period 2001-2002 and analyze their return intervals τ , which are time intervals between volatilities above a given threshold q . We explore the probability density function of τ , Pq(τ) , assuming a stretched exponential function, Pq(τ)˜e-τγ . We find that the exponent γ depends on the threshold in the range between q=1 and 6 standard deviations of the volatility. This finding supports the multiscaling nature of the return interval distribution. To better understand the multiscaling origin, we study how γ depends on four essential factors, capitalization, risk, number of trades, and return. We show that γ depends on the capitalization, risk, and return but almost does not depend on the number of trades. This suggests that γ relates to the portfolio selection but not on the market activity. To further characterize the multiscaling of individual stocks, we fit the moments of τ , μm≡⟨(τ/⟨τ⟩)m⟩1/m , in the range of 10portfolio optimization.

  15. ParaExp Using Leapfrog as Integrator for High-Frequency Electromagnetic Simulations

    Science.gov (United States)

    Merkel, M.; Niyonzima, I.; Schöps, S.

    2017-12-01

    Recently, ParaExp was proposed for the time integration of linear hyperbolic problems. It splits the time interval of interest into subintervals and computes the solution on each subinterval in parallel. The overall solution is decomposed into a particular solution defined on each subinterval with zero initial conditions and a homogeneous solution propagated by the matrix exponential applied to the initial conditions. The efficiency of the method depends on fast approximations of this matrix exponential based on recent results from numerical linear algebra. This paper deals with the application of ParaExp in combination with Leapfrog to electromagnetic wave problems in time domain. Numerical tests are carried out for a simple toy problem and a realistic spiral inductor model discretized by the Finite Integration Technique.

  16. Integrated Oil spill detection and forecasting using MOON real time data

    OpenAIRE

    De Dominicis, M.; Pinardi, N.; Coppini, G.; Tonani, M.; Guarnieri, A.; Zodiatis, G.; Lardner, R.; Santoleri, R.

    2009-01-01

    MOON (Mediterranean Operational Oceanography Network) is an operational distributed system ready to provide quality controlled and timely marine observations (in situ and satellite) and environmental analyses and predictions for management of oil spill accidents. MOON operational systems are based upon the real time functioning of an integrated system composed of the Real Time Observing system, the regional, sub-regional and coastal forecasting systems and a products dissemination system. All...

  17. Reducing Error Bars through the Intercalibration of Radioisotopic and Astrochronologic Time Scales for the Cenomanian/Turonian Boundary Interval, Western Interior Basin, USA

    Science.gov (United States)

    Meyers, S. R.; Siewert, S. E.; Singer, B. S.; Sageman, B. B.; Condon, D. J.; Obradovich, J. D.; Jicha, B.; Sawyer, D. A.

    2010-12-01

    We develop a new intercalibrated astrochronologic and radioisotopic time scale for the Cenomanian/Turonian (C/T) boundary interval near the GSSP in Colorado, where orbitally-influenced rhythmic strata host bentonites that contain sanidine and zircon suitable for 40Ar/39Ar and U-Pb dating. This provides a rare opportunity to directly intercalibrate two independent radioisotopic chronometers against an astrochronologic age model. We present paired 40Ar/39Ar and U-Pb ages from four bentonites spanning the Vascoceras diartianum to Pseudaspidoceras flexuosum biozones, utilizing both newly collected material and legacy sanidine samples of Obradovich (1993). Full 2σ uncertainties (decay constant, standard age, analytical sources) for the 40Ar/39Ar ages, using a weighted mean of 33-103 concordant age determinations and an age of 28.201 Ma for Fish Canyon sanidine (FCs), range from ±0.15 to 0.19 Ma, with ages from 93.67 to 94.43 Ma. The traditional FCs age of 28.02 Ma yields ages from 93.04 to 93.78 Ma with full uncertainties of ±1.58 Ma. Using the ET535 tracer, single zircon CA-TIMS 206Pb/238U ages determined from each bentonite record a range of ages (up to 2.1 Ma), however, in three of the four bentonites the youngest single crystal ages are statistically indistinguishable from the 40Ar/39Ar ages calculated relative to 28.201 Ma FCs, supporting this calibration. Using the new radioisotopic data and published astrochronology (Sageman et al., 2006) we develop an integrated C/T boundary time scale using a Bayesian statistical approach that builds upon the strength of each geochronologic method. Whereas the radioisotopic data provide an age with a well-defined uncertainty for each bentonite, the orbital time scale yields a more highly resolved estimate of the duration between stratigraphic horizons, including the radioisotopically dated beds. The Bayesian algorithm yields a C/T time scale that is statistically compatible with the astrochronologic and radioisotopic data

  18. Measurement of time-integrated $D^0\\to hh$ asymmetries at LHCb

    CERN Document Server

    Marino, Pietro

    2016-01-01

    LHCb collected the world’s largest sample of charm decays during LHC Run I, corresponding to an integrated luminosity of 3fb$^{−1}$. This has permitted many precision measurements of charm mixing and CP violation parameters. One of the most precise and important observables is the so-called $\\Delta A_{CP}$ parameter, corresponding to the difference between the time-integrated CP asymmetry in singly Cabibbo-suppressed $D^{0} \\rightarrow K^{+}K^{-}$ and $D^{0} \\rightarrow \\pi^{+}\\pi{-}$ decay modes. The flavour of the $D^{0}$ meson is inferred from the charge of the pion in $D^{∗+} \\rightarrow D^{0}\\pi^{+}$ and $D^{∗−} \\rightarrow \\overline{D}^{0}\\pi^{-}$ decays. $\\Delta A_{CP} \\equiv A_{raw}(K^{+}K^{−})−A_{raw}(\\pi^{+}\\pi{−})$ is measured to be $\\Delta A_{CP}=(−0.10±0.08±0.03)$%, where the first uncertainty is statistical and the second systematic. The measurement is consistent with the no- CP -violation hypothesis and represents the most precise measurement of time-integrated CP asymmetry ...

  19. Interference Cancellation Using Replica Signal for HTRCI-MIMO/OFDM in Time-Variant Large Delay Spread Longer Than Guard Interval

    Directory of Open Access Journals (Sweden)

    Yuta Ida

    2012-01-01

    Full Text Available Orthogonal frequency division multiplexing (OFDM and multiple-input multiple-output (MIMO are generally known as the effective techniques for high data rate services. In MIMO/OFDM systems, the channel estimation (CE is very important to obtain an accurate channel state information (CSI. However, since the orthogonal pilot-based CE requires the large number of pilot symbols, the total transmission rate is degraded. To mitigate this problem, a high time resolution carrier interferometry (HTRCI for MIMO/OFDM has been proposed. In wireless communication systems, if the maximum delay spread is longer than the guard interval (GI, the system performance is significantly degraded due to the intersymbol interference (ISI and intercarrier interference (ICI. However, the conventional HTRCI-MIMO/OFDM does not consider the case with the time-variant large delay spread longer than the GI. In this paper, we propose the ISI and ICI compensation methods for a HTRCI-MIMO/OFDM in the time-variant large delay spread longer than the GI.

  20. Evaluation of test intervals strategies with a risk monitor

    International Nuclear Information System (INIS)

    Soerman, J.

    2005-01-01

    The Swedish nuclear power utility Oskarshamn Power Group (OKG), is investigating how the use of a risk monitor can facilitate and improve risk-informed decision-making at their nuclear power plants. The intent is to evaluate if risk-informed decision-making can be accepted. A pilot project was initiated and carried out in 2004. The project included investigating if a risk monitor can be used for optimising test intervals for diesel- and gas turbine generators with regard to risk level. The Oskarhamn 2 (O2), PSA Level 1 model was converted into a risk monitor using RiskSpectrum RiskWatcher (RSRW) software. The converted PSA model included the complete PSA model for the power operation mode. RSRW then performs a complete requantification for every analysis. Time dependent reliability data are taken into account, i.e. a shorter test interval will increases the components availability (possibility to e.g. start on demand). The converted O2 model was then used to investigate whether it would be possible to balance longer test intervals for diesel generators, gas turbine generators and high pressure injection system with shorter test intervals for the low pressure injection system, while maintaining a low risk level at the plant. The results show that a new mixture of test intervals can be implemented with only marginally changes in the risk calculated with the risk monitor model. The results indicate that the total number of test activities for the systems included in the pilot study could be reduced by 20% with a maintained level of risk. A risk monitor taking into account the impact from test intervals in availability calculations for components is well suited for evaluation of test interval strategies. It also enables the analyst to evaluate the risk level over a period of time including the impact the actual status of the plant may have on the risk level. (author)