730 research outputs found
Sampled-data fuzzy controller for continuous nonlinear systems
The sampled-data fuzzy control of nonlinear systems is presented. The consequents of the fuzzy controller rules are linear sampled-data sub-controllers. As a result, the fuzzy controller is a weighted sum of some linear sampled-data sub-controllers that can be implemented by a microcontroller or a digital computer to lower the implementation cost. Consequently, a hybrid fuzzy controller consisting of continuous-time grades of memberships and discrete-time sub-controller is obtained. The system stability of the fuzzy control system is investigated on the basis of Lyapunov-based approach. The sampling activity introduces discontinuity to complicate the system dynamics and make the stability analysis difficult. The proposed fuzzy controller exhibits a favourable property to alleviate the conservativeness of the stability analysis. Furthermore, linear matrix inequality-based performance conditions are derived to guarantee the system performance of the fuzzy control system. An application example is given to illustrate the merits of the proposed approac
Dynamical and stationary critical behavior of the Ising ferromagnet in a thermal gradient
In this paper we present and discuss results of Monte Carlo numerical
simulations of the two-dimensional Ising ferromagnet in contact with a heat
bath that intrinsically has a thermal gradient. The extremes of the magnet are
at temperatures , where is the Onsager critical temperature.
In this way one can observe a phase transition between an ordered phase
() by means of a single simulation. By
starting the simulations with fully disordered initial configurations with
magnetization corresponding to , which are then suddenly
annealed to a preset thermal gradient, we study the short-time critical dynamic
behavior of the system. Also, by setting a small initial magnetization ,
we study the critical initial increase of the order parameter. Furthermore, by
starting the simulations from fully ordered configurations, which correspond to
the ground state at T=0 and are subsequently quenched to a preset gradient, we
study the critical relaxation dynamics of the system. Additionally, we perform
stationary measurements () that are discussed in terms of
the standard finite-size scaling theory. We conclude that our numerical
simulation results of the Ising magnet in a thermal gradient, which are
rationalized in terms of both dynamic and standard scaling arguments, are fully
consistent with well established results obtained under equilibrium conditions
Effects of denosumab in Japanese patients with rheumatoid arthritis treated with conventional antirheumatic drugs: 36-month extension of a Phase III study
Objective. To evaluate the safety and efficacy of long-term denosumab 60 mg every 6 months (Q6M) or every 3 months (Q3M) in patients with rheumatoid arthritis (RA). Methods. This 12-month, randomized, double-blind, placebo-controlled, multicenter, phase III trial with an open-label extension period from 12 to 36 months (DESIRABLE) enrolled Japanese patients with RA treated with placebo (P) for 12 months followed by either denosumab Q6M (P/Q6M) or denosumab Q3M (P/Q3M) for 24 months; denosumab Q6M for 36 months (Q6M/Q6M); or denosumab Q3M for 36 months (Q3M/Q3M). Efficacy was assessed by van der Heijde modified total Sharp score (mTSS), bone erosion score (BES), and joint space narrowing (JSN) score. Results. Long-term treatment better maintained mTSS and BES suppression in the P/Q3M and Q3M/ Q3M vs P/Q6M and Q6M/Q6M groups; changes from baseline in total mTSS (standard error) at 36 months were 2.8 (0.4) and 1.7 (0.3) vs 3.0 (0.4) and 2.4 (0.3), respectively, and corresponding changes in BES were 1.3 (0.2) and 0.4 (0.2) vs 1.4 (0.2) and 1.1 (0.2), respectively. No JSN effect was observed. Bone mineral density consistently increased in all groups after denosumab initiation, regardless of concomitant glucocorticoid administration. Serum C-terminal telopeptide of type I collagen decreased rapidly at 1 month postdenosumab administration (in both the initial 12-month [Q3M and Q6M groups] and long-term treatment [P/Q3M and P/Q6M groups] phases). Adverse event incidence leading to study drug discontinuation was similar across treatment groups. Conclusion. Denosumab treatment maintained inhibition of progression of joint destruction up to 36 months. Based on effects on BES progression, higher dosing frequency at an earlier treatment stage may be needed to optimize treatment. Denosumab was generally well tolerated. (ClinicalTrials.gov: NCT01973569).Pathophysiology and treatment of rheumatic disease
Aging at Criticality in Model C Dynamics
We study the off-equilibrium two-point critical response and correlation
functions for the relaxational dynamics with a coupling to a conserved density
(Model C) of the O(N) vector model. They are determined in an \epsilon=4-d
expansion for vanishing momentum. We briefly discuss their scaling behaviors
and the associated scaling forms are determined up to first order in epsilon.
The corresponding fluctuation-dissipation ratio has a non trivial large time
limit in the aging regime and, up to one-loop order, it is the same as that of
the Model A for the physically relevant case N=1. The comparison with
predictions of local scale invariance is also discussed.Comment: 13 pages, 1 figur
Evolution and Flare Activity of Delta-Sunspots in Cycle 23
The emergence and magnetic evolution of solar active regions (ARs) of
beta-gamma-delta type, which are known to be highly flare-productive, were
studied with the SOHO/MDI data in Cycle 23. We selected 31 ARs that can be
observed from their birth phase, as unbiased samples for our study. From the
analysis of the magnetic topology (twist and writhe), we obtained the following
results. i) Emerging beta-gamma-delta ARs can be classified into three
topological types as "quasi-beta", "writhed" and "top-to-top". ii) Among them,
the "writhed" and "top-to-top" types tend to show high flare activity. iii) As
the signs of twist and writhe agree with each other in most cases of the
"writhed" type (12 cases out of 13), we propose a magnetic model in which the
emerging flux regions in a beta-gamma-delta AR are not separated but united as
a single structure below the solar surface. iv) Almost all the "writhed"-type
ARs have downward knotted structures in the mid portion of the magnetic flux
tube. This, we believe, is the essential property of beta-gamma-delta ARs. v)
The flare activity of beta-gamma-delta ARs is highly correlated not only with
the sunspot area but also with the magnetic complexity. vi) We suggest that
there is a possible scaling-law between the flare index and the maximum umbral
area
Search for the Electric Dipole Moment of the tau Lepton
We have searched for a CP violation signature arising from an electric dipole
moment (d_tau) of the tau lepton in the e+e- -> tau+tau- reaction. Using an
optimal observable method and 29.5 fb^{-1} of data collected with the Belle
detector at the KEKB collider at sqrt{s} = 10.58 GeV, we find Re(d_tau) = (1.15
+- 1.70) x 10^{-17} ecm and Im(d_tau) = (-0.83 +- 0.86) x 10^{-17} ecm and set
the 95% confidence level limits -2.2 < Re(d_tau) < 4.5 (10^{-17}ecm) and -2.5 <
Im(d_tau) < 0.8 (10^{-17}ecm).Comment: 15 pages, LaTeX, 21 figures, submitted to Phys. Lett.
Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decays
We present measurements of the Cabibbo-suppressed decays Lambda_c^+ -->
Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+
--> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+
--> p K+ K- and Lambda_c^+ --> p phi (measured with improved accuracy).
Improved branching ratio measurements for the decays Lambda_c^+ --> Sigma+ K+
K- and Lambda_c^+ --> Sigma+ phi, which are attributed to W-exchange diagrams,
are shown. We also present the first evidence for Lambda_c^+ --> Xi(1690)^0 K+
and set an upper limit on the non-resonant decay Lambda_c^+ --> Sigma+ K+ K-.
This analysis was performed using 32.6 fb^{-1} of data collected by the Belle
detector at the asymmetric e+ e- collider KEKB.Comment: Submitted to Phys. Lett. B. v2: A small correction to the Authorlist
was made. An earlier version of this analysis was released as
BELLE-CONF-0130, hep-ex/010800
Measurement of the Branching Fraction for B->eta' K and Search for B->eta'pi+
We report measurements for two-body charmless B decays with an eta' meson in
the final state. Using 11.1X10^6 BBbar pairs collected with the Belle detector,
we find BF(B^+ ->eta'K^+)=(79^+12_-11 +-9)x10^-6 and BF(B^0 ->
eta'K^0)=(55^+19_-16 +-8)x10^-6, where the first and second errors are
statistical and systematic, respectively. No signal is observed in the mode B^+
-> eta' pi^+, and we set a 90% confidence level upper limit of BF(B^+->
eta'pi^+) eta'K^+- decays is
investigated and a limit at 90% confidence level of -0.20<Acp<0.32 is obtained.Comment: Submitted to Physics Letters
Precise measurement of hadronic tau-decays with an eta meson
We have studied hadronic tau decay modes involving an eta meson using 490
fb^{-1} of data collected with the Belle detector at the KEKB asymmetric-energy
e+e- collider. The following branching fractions have been measured: B(tau- ->
K- eta nu)=(1.58 +- 0.05 +- 0.09)x 10^{-4}, B(tau- -> K- pi0 eta nu)=(4.6 +-
1.1 +- 0.4)x 10^{-5}, B(tau- -> pi- pi0 eta nu)=(1.35 +- 0.03 +- 0.07)x
10^{-3}, B(tau- -> pi- KS eta nu)=(4.4 +- 0.7 +- 0.2)x 10^{-5}, and B(tau- ->
K^{*-} eta nu)=(1.34 +- 0.12 +- 0.09)x 10^{-4}. These results are substantially
more precise than previous measurements. The new measurements are compared with
theoretical calculations based on the CVC hypothesis or the chiral perturbation
theory. We also set upper limits on branching fractions for tau decays into K-
KS eta nu, pi- KS pi0 eta nu, K- eta eta nu, pi- eta eta nu and non-resonant K-
pi^0 eta nu final states.Comment: 24 pages, 7 figure
Determination of |Vcb| using the semileptonic decay \bar{B}^0 --> D^{*+}e^-\bar{\nu}
We present a measurement of the Cabibbo-Kobayashi-Maskawa (CKM) matrix
element |Vcb| using a 10.2 fb^{-1} data sample recorded at the \Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.
By extrapolating the differential decay width of the \bar{B}^0 -->
D^{*+}e^-\bar{\nu} decay to the kinematic limit at which the D^{*+} is at rest
with respect to the \bar{B}^0, we extract the product of |Vcb| with the
normalization of the decay form factor F(1), |Vcb |F(1)=
(3.54+/-0.19+/-0.18)x10^{-2}, where the first error is statistical and the
second is systematic. A value of |Vcb| = (3.88+/-0.21+/-0.20+/-0.19)x10^{-2} is
obtained using a theoretical calculation of F(1), where the third error is due
to the theoretical uncertainty in the value of F(1). The branching fraction
B(\bar{B}^0 --> D^{*+}e^-\bar{\nu}) is measured to be
(4.59+/-0.23+/-0.40)x10^{-2}.Comment: 20 pages, 6 figures, elsart.cls, submitted to PL
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