8,333 research outputs found
Identification of the multiscale fractional Brownian motion with biomechanical applications
In certain applications, for instance biomechanics, turbulence, finance, or
Internet traffic, it seems suitable to model the data by a generalization of a
fractional Brownian motion for which the Hurst parameter is depending on
the frequency as a piece-wise constant function. These processes are called
multiscale fractional Brownian motions. In this contribution, we provide a
statistical study of the multiscale fractional Brownian motions. We develop a
method based on wavelet analysis. By using this method, we find initially the
frequency changes, then we estimate the different parameters and afterwards we
test the goodness-of-fit. Lastly, we give the numerical algorithm.
Biomechanical data are then studied with these new tools
Filtered derivative with p-value method for multiple change-points detection
This paper deals with off-line detection of change points for time series of
independent observations, when the number of change points is unknown. We
propose a sequential analysis like method with linear time and memory
complexity. Our method is based at first step, on Filtered Derivative method
which detects the right change points but also false ones. We improve Filtered
Derivative method by adding a second step in which we compute the p-values
associated to each potential change points. Then we eliminate as false alarms
the points which have p-value smaller than a given critical level. Next, our
method is compared with the Penalized Least Square Criterion procedure on
simulated data sets. Eventually, we apply Filtered Derivative with p-Value
method to segmentation of heartbeat time series
Simplicity of twin tree lattices with non-trivial commutation relations
We prove a simplicity criterion for certain twin tree lattices. It applies to
all rank two Kac-Moody groups over finite fields with non-trivial commutation
relations, thereby yielding examples of simple non-uniform lattices in the
product of two trees
The interplay of uncertainty, structure and trust on the diffusion of management accounting and control systems: An agent based modeling approach
This study attempts to investigate the interplay of uncertainty, structure and trust on the diffusion of a subset of management information systems, namely management accounting and control systems. The article suggests that under conditions of uncertainty, trust and structure are significantly associated with the success of the implementation process. On the other hand, the importance of trust and structure is less significant when the management accounting and control system is not perceived as threatening to organizational actors. The study draws on social network theory and proposes an agent based modeling approach to study the interplay of uncertainty, trust and structure on the diffusion process.
On time preference, rational addiction and utility satiation
A basic consumer problem with a unique good is considered, current consumption of this good influencing in a positive manner consumer intertemporal utility, while past consumption exerts a negative influence. Moreover, in the line of Fisher, a specification of preferences is retained so that the rate of time preference, assumes a long-run value â this means for a stationary consumption-path â that is non-monotonic as a function of consumption: impatience increases for low level of consumptions but decreases for higher ones. Such a framework allows for an integrated appraisal of addiction, satiation and the rate of time preference. It is shown that the emergence of an addiction phenomenon in the neighbourhood of an unsatiated long-run position exactly corresponds to letting the rate of time preference be an increasing function of past consumption habits. When addiction becomes sufficiently strong, the unsatiated stationary state becomes unstable and the satiated steady state becomes the only admissible stationary position.Impatience; Consumption habits; Rational addiction; Satiation
Off-line detection of multiple change points with the Filtered Derivative with p-Value method
This paper deals with off-line detection of change points for time series of
independent observations, when the number of change points is unknown. We
propose a sequential analysis like method with linear time and memory
complexity. Our method is based at first step, on Filtered Derivative method
which detects the right change points but also false ones. We improve Filtered
Derivative method by adding a second step in which we compute the p-values
associated to each potential change points. Then we eliminate as false alarms
the points which have p-value smaller than a given critical level. Next, our
method is compared with the Penalized Least Square Criterion procedure on
simulated data sets. Eventually, we apply Filtered Derivative with p-Value
method to segmentation of heartbeat time series, and detection of change points
in the average daily volume of financial time series
Fast change point analysis on the Hurst index of piecewise fractional Brownian motion
In this presentation, we introduce a new method for change point analysis on
the Hurst index for a piecewise fractional Brownian motion. We first set the
model and the statistical problem. The proposed method is a transposition of
the FDpV (Filtered Derivative with p-value) method introduced for the detection
of change points on the mean in Bertrand et al. (2011) to the case of changes
on the Hurst index. The underlying statistics of the FDpV technology is a new
statistic estimator for Hurst index, so-called Increment Bernoulli Statistic
(IBS). Both FDpV and IBS are methods with linear time and memory complexity,
with respect to the size of the series. Thus the resulting method for change
point analysis on Hurst index reaches also a linear complexity
Second-Order Phase Transition Induced by Deterministic Fluctuations in Aperiodic Eight-State Potts Models
We investigate the influence of aperiodic modulations of the exchange
interactions between nearest-neighbour rows on the phase transition of the
two-dimensional eight-state Potts model. The systems are studied numerically
through intensive Monte Carlo simulations using the Swendsen-Wang cluster
algorithm for different aperiodic sequences. The transition point is located
through duality relations, and the critical behaviour is investigated using FSS
techniques at criticality. While the pure system exhibits a first-order
transition, we show that the deterministic fluctuations resulting from the
aperiodic coupling distribution are liable to modify drastically the physical
properties in the neighbourhood of the transition point. For strong enough
fluctuations of the sequence under consideration, a second-order phase
transition is induced. The exponents , and
are obtained at the new fixed point and crossover effects are
discussed. Surface properties are also studied.Comment: LaTeX file with EPJB macro package, 11 pages, 16 postscript figures,
to appear in Eur. Phys. J.
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