Due to industrialization, there is a demand for rapid and highly accurate frequency estimator. The present paper tackles the identification problem of a damped sinusoidal signal in real time. To this end, an algebraic approach is employed. The authors derive an integral form of the frequency estimation algorithm by using the Laplace transform. In order to treat a noisy observation problem, the paper introduces a postfilter. The validity of the proposed algorithm is confirmed through numerical simulations in MATLAB/Simulink environment.

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In nonlinear output regulation problems, it is necessary to solve the so-called regulator equations consisting of a partial differential equation and an algebraic equation. It is known that, for the hyperbolic zero dynamics case, solving the regulator equations is equivalent to calculating a center manifold for zero dynamics of the system. The present paper proposes a successive approximation method for obtaining center manifolds and shows its effectiveness by applying it for an inverted pendulum example.

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In this paper, we investigate the state preparation problem of quantum noiselsss subsystems for the quantum Markovian systems via quantum feedback control. The controlled dynamics we consider are given by the so-called stochastic master equation including the coupling terms with the environment. We formulate the problem as a stochastic stabilization problem of an invariant set. This formulation allows us to utilize the stochastic Lyapunov technique and derive a globally stabilizing controller. The effectiveness of this method is evaluated by applying it to the 3-qubit systems subject to the collective noise.

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This paper proposes a method to design gain-scheduled controllers by using LMIs that depend on filtered scheduling parameters. This avoids the drawback of previous results that require differentiation of scheduling parameters. Moreover, with small damping time of the filter, our gain-scheduled controllers recover performance of those previous unimplementable controllers that need accurate derivative of parameters.

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This paper deals with a hierarchical consensus problem in large scale systems. We first define the hierarchical consensus and propose a fairly general model of the system. We then define the incidence matrix which expresses interconnection property between layers, where we focus on the rank of the matrix. In order to examine the relationship between the rank of inter-layer incidence matrix and consensus performance, we analytically derive the eigenvalue distribution of the sysytem matrix in the case of circulant incidence matrix. The resultant distribution shows that the low-rank interconnection leads to the faster consensus in terms of rate of convergence and damping, which is confirmed by numerical examples with simulations.

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Pressing a blood vessel makes stopping natural flow of blood and brings into a change of color in surface of tissues from red to white. This phenomenon is called ”ischemia”. Such ischemia can be characterized by the time constant in the first order system. An issue in capturing the ischemia information is that the captured color includes two components, one comes from the blood itself and the other comes from the change of reflected condition due to the inclination of surface of tissue. This paper proposes an approach for evaluating the time constant due to the ischemia by considering the difference between the time constant by ischemia and the time constant by deformation. The proposed method is applied to our finger tip so that we can confirm its effectiveness.

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This note studies the controllability and the observability for linear time-invariant uncertain systems whose system matrices contain uncertain entries that may take arbitrary large values. For a certain class of systems, it has been shown that a system is controllable and observable irrespectively of the bounds of uncertain entries if and only if the system has a particular geometric configuration called a complete generalized antisymmetric stepwise configuration. In this note, using the duality between the controllability and the observability, we show a necessary and sufficient condition for the system belonging a new class of systems to be controllable and observable independently of the bounds of uncertain entries.

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