11,123 research outputs found
Observer-based decentralized approach to robotic formation control
Control of a group of mobile robots in a formation requires not only environmental sensing but also communication among vehicles. Enlarging the size of the platoon of vehicles causes difficulties due to communications bandwidth limitations. Decentralized control may be an appropriate approach in those cases when the states of all vehicles cannot be obtained in a centralized manner. This paper presents a solution to the problem of decentralized implementation of a global state-feedback controller for N mobile robots in a formation. The proposed solution is based on the design of functional observers to estimate asymptotically the global state-feedback control signals by using the corresponding local output information and some exogenous global functions. The proposed technique is tested through simulation and experiments for the control of groups of Pinoneer-based non-holonomic mobile robots.<br /
Dynamic output feedback sliding-mode control using pole placement and linear functional observers
This paper presents a methodological approach to design dynamic output feedback sliding-mode control for a class of uncertain dynamical systems. The control action consists of the equivalent control and robust control components. The design of the equivalent control and the sliding function are based on the pole-placement technique. Linear functional observers are developed to implement the sliding function and the equivalent control. Stability of the resulting system under the proposed control scheme is guaranteed. A numerical example is given to demonstrate its efficacy.<br /
Susceptibility weighted imaging (SWI) for the assessment of iron loading in the brain of beta-thalassemia major patients
postprintThe 2010 Joint Annual Meeting of ISMRM-ESMRMB, Stockholm, Sweden, 1-7 May 2010
Neutrino induced reactions related to the -process nucleosynthesis of Nb and Tc
It has recently been proposed that Nb and Tc may
have been formed in the -process. We investigate the neutrino induced
reactions related to the -process origin of the two odd-odd nuclei. The
main neutrino reactions for Nb are the charged-current (CC)
Zr()Nb and the neutral-current (NC) Nb( n)Nb reactions. The main
reactions for Tc, are the CC reaction
Mo()Tc and the NC reaction Ru( p)Tc. Our calculations are carried
out using the quasi-particle random phase approximation. Numerical results are
presented for the energy and temperature dependent cross sections. Since charge
exchange reactions by neutrons may also lead to the formation of
Nb and Tc, we discuss the feasibility of the
Mo(n,p)Nb and Ru(n,p)Tc reactions to produce these
nuclei.Comment: 21 pages, 8 figure
Exact dynamical structure factor of the degenerate Haldane-Shastry model
The dynamical structure factor of the K-component (K = 2,3,4)
spin chain with the 1/r^2 exchange is derived exactly at zero temperature for
arbitrary size of the system. The result is interpreted in terms of a free
quasi-particle picture which is generalization of the spinon picture in the
SU(2) case; the excited states consist of K quasi-particles each of which is
characterized by a set of K-1 quantum numbers. Divergent singularities of
at the spectral edges are derived analytically. The analytic
result is checked numerically for finite systems.Comment: 4 pages, 1 figure, accepted for publication in Phys. Rev. Let
Dengue epidemic in southern Vietnam, 1998.
A widespread epidemic of dengue hemorrhagic fever (DHF) occurred in southern Vietnam in 1998, with 438.98 cases/100,000 population and 342 deaths. The number of DHF cases and deaths per 100,000 population increased 152.4% and 151.8%, respectively, over a 1997 epidemic. Dengue viruses were isolated from 143 patient blood samples; DEN-3 virus was identified as the predominant serotype, although a resurgence of DEN-4 was noted
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