4,257 research outputs found
Linear-quadratic stochastic differential games for distributed parameter systems
A linear-quadratic differential game with infinite dimensional state space is considered. The system state is affected by disturbance and both players have access to different measurements. Optimal linear strategies for the pursuer and the evader, when they exist, are explicitly determined
Parameter estimation of electricity spot models from futures prices
We consider a slight perturbation of the Schwartz-Smith model for the electricity futures prices and the resulting modified spot model. Using the martingale property of the modified price under the risk neutral measure, we derive the arbitrage free model for the spot and futures prices. We estimate the parameters of the model by the method of maximum likelihood using the Kalman filter's estimate of the unobservable state variables, coupled with the usual statistical techniques. The main advantage of the new model is that it avoids the inclusion of artificial noise to the observation equation for the implementation of Kalman filter. The extra noise is build in within the model in an arbitrage free setting
Towards dynamical network biomarkers in neuromodulation of episodic migraine
Computational methods have complemented experimental and clinical
neursciences and led to improvements in our understanding of the nervous
systems in health and disease. In parallel, neuromodulation in form of electric
and magnetic stimulation is gaining increasing acceptance in chronic and
intractable diseases. In this paper, we firstly explore the relevant state of
the art in fusion of both developments towards translational computational
neuroscience. Then, we propose a strategy to employ the new theoretical concept
of dynamical network biomarkers (DNB) in episodic manifestations of chronic
disorders. In particular, as a first example, we introduce the use of
computational models in migraine and illustrate on the basis of this example
the potential of DNB as early-warning signals for neuromodulation in episodic
migraine.Comment: 13 pages, 5 figure
SDSS J0349-0059 is a GW Virginis star
High speed photometric observations of the spectroscopically-discovered PG
1159 star SDSS J034917.41-005917.9 in 2007 and 2009 reveal a suite of pulsation
frequencies in the range of 1038 - 3323 microHz with amplitudes between 3.5 and
18.6 mmag. SDSS J034917.41-005917.9 is therefore a member of the GW Vir class
of pulsating pre-white dwarfs. We have identified 10 independent pulsation
frequencies that can be fitted by an asymptotic model with a constant period
spacing of 23.61 +/- 0.21 s, presumably associated with a sequence of l = 1
modes. The highest amplitude peak in the suite of frequencies shows evidence
for a triplet structure, with a frequency separation of 14.4 microHz. Five of
the identified frequencies do not fit the l = 1 sequence, but are, however,
well-modeled by an independent asymptotic sequence with a constant period
spacing of 11.66 +/- 0.13 s. It is unclear to which l mode these frequencies
belong.Comment: Accepted for publication in MNRAS; 5 pages, 6 figures and 4 table
Synchronization of Coupled Nonidentical Genetic Oscillators
The study on the collective dynamics of synchronization among genetic
oscillators is essential for the understanding of the rhythmic phenomena of
living organisms at both molecular and cellular levels. Genetic oscillators are
biochemical networks, which can generally be modelled as nonlinear dynamic
systems. We show in this paper that many genetic oscillators can be transformed
into Lur'e form by exploiting the special structure of biological systems. By
using control theory approach, we provide a theoretical method for analyzing
the synchronization of coupled nonidentical genetic oscillators. Sufficient
conditions for the synchronization as well as the estimation of the bound of
the synchronization error are also obtained. To demonstrate the effectiveness
of our theoretical results, a population of genetic oscillators based on the
Goodwin model are adopted as numerical examples.Comment: 16 pages, 3 figure
Probing Trilinear Gauge Boson Interactions via Single Electroweak Gauge Boson Production at the LHC
We analyze the potential of the CERN Large Hadron Collider (LHC) to study
anomalous trilinear vector-boson interactions W^+ W^- \gamma and W^+ W^- Z
through the single production of electroweak gauge bosons via the weak boson
fusion processes q q -> q q W (-> \ell^\pm \nu) and q q -> q q Z(-> \ell^+
\ell^-) with \ell = e or \mu. After a careful study of the standard model
backgrounds, we show that the single production of electroweak bosons at the
LHC can provide stringent tests on deviations of these vertices from the
standard model prediction. In particular, we show that single gauge boson
production exhibits a sensitivity to the couplings \Delta \kappa_{Z,\gamma}
similar to that attainable from the analysis of electroweak boson pair
production.Comment: 20 pages, 6 figure
Chaotic Phase Synchronization in Bursting-neuron Models Driven by a Weak Periodic Force
We investigate the entrainment of a neuron model exhibiting a chaotic
spiking-bursting behavior in response to a weak periodic force. This model
exhibits two types of oscillations with different characteristic time scales,
namely, long and short time scales. Several types of phase synchronization are
observed, such as 1 : 1 phase locking between a single spike and one period of
the force and 1 : l phase locking between the period of slow oscillation
underlying bursts and l periods of the force. Moreover, spiking-bursting
oscillations with chaotic firing patterns can be synchronized with the periodic
force. Such a type of phase synchronization is detected from the position of a
set of points on a unit circle, which is determined by the phase of the
periodic force at each spiking time. We show that this detection method is
effective for a system with multiple time scales. Owing to the existence of
both the short and the long time scales, two characteristic phenomena are found
around the transition point to chaotic phase synchronization. One phenomenon
shows that the average time interval between successive phase slips exhibits a
power-law scaling against the driving force strength and that the scaling
exponent has an unsmooth dependence on the changes in the driving force
strength. The other phenomenon shows that Kuramoto's order parameter before the
transition exhibits stepwise behavior as a function of the driving force
strength, contrary to the smooth transition in a model with a single time
scale
ANOMALOUS GAUGE BOSON INTERACTIONS
We discuss the direct measurement of the trilinear vector boson couplings in
present and future collider experiments. The major goals of such experiments
will be the confirmation of the Standard Model (SM) predictions and the search
for signals of new physics. We review our current theoretical understanding of
anomalous trilinear gauge boson self-interactions. If the energy scale of the
new physics is TeV, these low energy anomalous couplings are expected
to be no larger than . Constraints from high precision
measurements at LEP and low energy charged and neutral current processes are
critically reviewed.Comment: 53 pages with 17 embedded figures, LaTeX, uses axodraw.sty, figures
available on request. The complete paper, is available at
ftp://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z or
http://phenom.physics.wisc.edu/pub/preprints/1995/madph-95-871.ps.Z Summary
of the DPF Working Subgroup on Anomalous Gauge Boson Interactions of the DPF
Long Range Planning Stud
First Observation of the Hadronic Transition ΄(4S)âηhb(1P)and New Measurement of the hb(1P) and ηb(1S) Parameters
Using a sample of 771.6Ă106 ΄΄(4S) decays collected by the Belle experiment at the KEKB e+eâ collider, we observe, for the first time, the transition ΄(4S)âηhb(1P) with the branching fraction B[΄(4S)âηhb(1P)]=(2.18±0.11±0.18)Ă10â3 and we measure the hb(1P) mass Mhb(1P)=(9899.3±0.4±1.0)ââMeV/c2, corresponding to the hyperfine (HF) splitting ÎMHF(1P)=(0.6±0.4±1.0)ââMeV/c2. Using the transition hb(1P)âγηb(1S), we measure the ηb(1S) mass Mηb(1S)=(9400.7±1.7±1.6)ââMeV/c2, corresponding to ÎMHF(1S)=(59.6±1.7±1.6)ââMeV/c2, the ηb(1S) width Îηb(1S)=(8+6â5±5)ââMeV/c2and the branching fraction B[hb(1P)âγηb(1S)]=(56±8±4)%
- âŠ