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[Author] Shun-ichi AZUMA(11hit)

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  • Performance Analysis of Demand Data Modification Mechanism for Power Balancing Control

    Yuki MINAMI  Shun-ichi AZUMA  

     
    LETTER-Systems and Control

      Vol:
    E98-A No:7
      Page(s):
    1562-1564

    For the electric demand prediction problem, a modification mechanism of predicted demand data has been proposed in the previous work. In this paper, we analyze the performance of the modification mechanism in power balancing control. Then, we analytically derive an upper bound of the performance, which is characterized by system parameters and prediction precision.

  • Designability of Multi-Attractor Boolean Networks with a Fixed Network Structure

    Shun-ichi AZUMA  Takahiro YOSHIDA  Toshiharu SUGIE  

     
    LETTER-Systems and Control

      Vol:
    E99-A No:1
      Page(s):
    423-425

    This paper addresses the designability of Boolean networks, i.e., the existence of a Boolean function satisfying an attractor condition under a given network structure. In particular, we present here a necessary and sufficient condition of the designability of Boolean networks with multiple attractors. The condition is characterized by the cyclicity of network structures, which allows us to easily determine the designability.

  • Optimal Movement for SLAM by Hopping Rover

    Shuntaro TAKEKUMA  Shun-ichi AZUMA  Ryo ARIIZUMI  Toru ASAI  

     
    PAPER

      Pubricized:
    2022/10/24
      Vol:
    E106-A No:5
      Page(s):
    715-720

    A hopping rover is a robot that can move in low gravity planets by the characteristic motion called the hopping motion. For its autonomous explorations, the so-called SLAM (Simultaneous Localization and Mapping) is a basic function. SLAM is the combination of estimating the position of a robot and creating a map of an unknown environment. Most conventional methods of SLAM are based on odometry to estimate the position of the robot. However, in the case of the hopping rover, the error of odometry becomes considerably large because its hopping motion involves unpredictable bounce on the rough ground on an unexplored planet. Motivated by the above discussion, this paper addresses a problem of finding an optimal movement of the hopping rover for the estimation performance of the SLAM. For the problem, we first set the model of the SLAM system for the hopping rover. The problem is formulated as minimizing the expectation of the estimation error at a pre-specified time with respect to the sequence of control inputs. We show that the optimal input sequence tends to force the final position to be not at the landmark but in front of the landmark, and furthermore, the optimal input sequence is constant on the time interval for optimization.

  • A Small-Data Solution to Data-Driven Lyapunov Equations: Data Reduction from O(n2) to O(n) Open Access

    Keitaro TSUJI  Shun-ichi AZUMA  Ikumi BANNO  Ryo ARIIZUMI  Toru ASAI  Jun-ichi IMURA  

     
    PAPER

      Pubricized:
    2023/10/24
      Vol:
    E107-A No:5
      Page(s):
    806-812

    When a mathematical model is not available for a dynamical system, it is reasonable to use a data-driven approach for analysis and control of the system. With this motivation, the authors have recently developed a data-driven solution to Lyapunov equations, which uses not the model but the data of several state trajectories of the system. However, the number of state trajectories to uniquely determine the solution is O(n2) for the dimension n of the system. This prevents us from applying the method to a case with a large n. Thus, this paper proposes a novel class of data-driven Lyapunov equations, which requires a smaller amount of data. Although the previous method constructs one scalar equation from one state trajectory, the proposed method constructs three scalar equations from any combination of two state trajectories. Based on this idea, we derive data-driven Lyapunov equations such that the number of state trajectories to uniquely determine the solution is O(n).

  • Discrete Abstraction of Stochastic Nonlinear Systems

    Shun-ichi AZUMA  George J. PAPPAS  

     
    PAPER

      Vol:
    E97-A No:2
      Page(s):
    452-458

    This paper addresses the discrete abstraction problem for stochastic nonlinear systems with continuous-valued state. The proposed solution is based on a function, called the bisimulation function, which provides a sufficient condition for the existence of a discrete abstraction for a given continuous system. We first introduce the bisimulation function and show how the function solves the problem. Next, a convex optimization based method for constructing a bisimulation function is presented. Finally, the proposed framework is demonstrated by a numerical simulation.

  • Dynamic Quantization of Nonaffine Nonlinear Systems

    Shun-ichi AZUMA  Toshiharu SUGIE  

     
    PAPER-Systems and Control

      Vol:
    E96-A No:10
      Page(s):
    1993-1998

    For quantized control, one of the powerful approaches is to use a dynamic quantizer, which has internal memories for signal quantization, with a conventional controller in the feedback control loop. The design of dynamic quantizers has become a major topic, and a number of results have been derived so far. In this paper, we extend the authors' recent result on dynamic quantizers, and applied them to a more general class of nonlinear systems, called the nonaffine nonlinear systems. Based on the performance index representing the degradation caused by the signal quantization, we propose practical dynamic quantizers, which include the authors' former result as a special case. Moreover, we provide theoretical results on the performance and on the stability of the resulting quantized systems.

  • Broadcast Control of Multi-Agent Systems with Quantized Measurements

    Yosuke TANAKA  Shun-ichi AZUMA  Toshiharu SUGIE  

     
    PAPER-Systems and Control

      Vol:
    E97-A No:3
      Page(s):
    830-839

    This paper addresses a broadcast control problem of multi-agent systems with quantized measurements, where each agent moves based on the common broadcasted signal and tries to minimize a given quadratic performance index. The problem is solved by introducing dither type random movements to the agents' action which reduce the degradation caused by quantized measurements. A broadcast controller is derived and it is proven that the controller approximately achieves given tasks with probability 1. The effectiveness of the proposed controller is demonstrated by numerical simulation.

  • Power Processing for Advanced Power Distribution and Control Open Access

    Ryo TAKAHASHI  Shun-ichi AZUMA  Mikio HASEGAWA  Hiroyasu ANDO  Takashi HIKIHARA  

     
    POSITION PAPER-Energy in Electronics Communications

      Pubricized:
    2016/12/14
      Vol:
    E100-B No:6
      Page(s):
    941-947

    A power packet dispatching system is proposed to realize the function of power on demand. This system distributes electrical power in quantized form, which is called power processing. This system has extensibility and flexibility. Here, we propose to use the power packet dispatching system as the next generation power distribution system in self-established and closed system such as robots, cars, and aircrafts. This paper introduces the concept and the required researches to take the power packet dispatching system in practical phase from the total viewpoints of devices, circuits, power electronics, system control, computer network, and bio-inspired power consumption.

  • FOREWORD Open Access

    Shun-ichi AZUMA  

     
    FOREWORD

      Vol:
    E104-A No:2
      Page(s):
    422-422
  • Analysis and Design of Aggregate Demand Response Systems Based on Controllability Open Access

    Kazuhiro SATO  Shun-ichi AZUMA  

     
    PAPER-Mathematical Systems Science

      Pubricized:
    2020/12/01
      Vol:
    E104-A No:6
      Page(s):
    940-948

    We address analysis and design problems of aggregate demand response systems composed of various consumers based on controllability to facilitate to design automated demand response machines that are installed into consumers to automatically respond to electricity price changes. To this end, we introduce a controllability index that expresses the worst-case error between the expected total electricity consumption and the electricity supply when the best electricity price is chosen. The analysis problem using the index considers how to maximize the controllability of the whole consumer group when the consumption characteristic of each consumer is not fixed. In contrast, the design problem considers the whole consumer group when the consumption characteristics of a part of the group are fixed. By solving the analysis problem, we first clarify how the controllability, average consumption characteristics of all consumers, and the number of selectable electricity prices are related. In particular, the minimum value of the controllability index is determined by the number of selectable electricity prices. Next, we prove that the design problem can be solved by a simple linear optimization. Numerical experiments demonstrate that our results are able to increase the controllability of the overall consumer group.

  • Controllability Analysis of Aggregate Demand Response System in Multiple Price-Change Situation

    Kazuhiro SATO  Shun-ichi AZUMA  

     
    PAPER

      Vol:
    E100-A No:2
      Page(s):
    376-384

    The paper studies controllability of an aggregate demand response system, i.e., the amount of the change of the total electric consumption in response to the change of the electric price, for real-time pricing (RTP). In order to quantify the controllability, this paper defines the controllability index as the lowest occurrence probability of the total electric consumption when the best possible the electric price is chosen. Then the paper formulates the problem which finds the consumer group maximizing the controllability index. The controllability problem becomes hard to solve as the number of consumers increases. To give a solution of the controllability problem, the article approximates the controllability index by the generalized central limit theorem. Using the approximated controllability index, the controllability problem can be reduced to a problem for solving nonlinear equations. Since the number of variables of the equations is independent of the number of consumers, an approximate solution of the controllability problem is obtained by numerically solving the equations.

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