研究活動情報

• 2024年07月 一般財団法人 敬愛まちづくり財団, 前之園記念若手優秀論文賞, Self-triggered stabilization of discrete-time linear systems with quantized state measurements

  若生 将史


• 2022年01月 公益財団法人 高柳健次郎財団, 研究奨励賞, 遅延を考慮した制御システムのセキュリティ対策アルゴリズムの開発

  若生 将史


• 2021年09月 計測自動制御学会, 著述賞, ネットワーク化制御，コロナ社，2019

  永原 正章, 岡野 訓尚, 小蔵 正輝, 若生 将史


• 2018年04月 船井情報科学振興財団, 2017年度 船井情報科学振興財団 研究奨励賞, 通信ネットワークを含む制御システムの解析・設計

  若生 将史

  出版社・新聞社・財団等の賞


• 2018年03月 計測自動制御学会制御部門, 2017年度 計測自動制御学会制御部門 部門大会賞, 確率的な時間遅れを含むシステムの最適制御

  若生 将史

  国内学会・会議・シンポジウム等の賞


• 2016年04月 ACM/IEEE, Best Paper Award of the ACM/IEEE 7th International Conference on Cyber-Physical Systems, SMT-Based observer design for cyber-physical systems under sensor attacks

  若生 将史

  国際学会・会議・シンポジウム等の賞


• 2015年01月 計測自動制御学会関西支部, 2014年度 計測自動制御学会関西支部 支部長賞奨励賞, サンプル値切替システムの量子化フィードバック安定化

  若生 将史

  国内学会・会議・シンポジウム等の賞


• 2014年03月 計測自動制御学会制御部門, 2013年度 計測自動制御学会制御部門 研究奨励賞, 安定なコントローラによるむだ時間系の混合感度低減化

  若生 将史

  国内学会・会議・シンポジウム等の賞


• 2014年02月 計測自動制御学会, 計測自動制御学会学会賞 学術奨励賞, 安定なコントローラによるむだ時間系の混合感度低減化

  若生 将史

  国内学会・会議・シンポジウム等の賞


• 2012年11月 システム制御情報学会, 第55回自動制御連合講演会 優秀発表賞, Skew Toeplitzアプローチによる無限次元システムの強安定・感度低減化

  若生 将史

  国内学会・会議・シンポジウム等の賞

• 範囲モデル予測型血糖値制御で用いられる入力ペナルティ関数の学習

  飯村 由信, 若生 将史

  The Society of Instrument and Control Engineers, 2024年08月, 計測自動制御学会論文集, 60(8) (8), 464 - 475, 日本語

  [査読有り]

  研究論文（学術雑誌）


• Decay estimates for Cayley transforms and inverses of semigroup generators via the B-calculus

  Masashi Wakaiki

  Abstract Let $$-A$$ be the generator of a bounded $$C_0$$-semigroup $$(e^{-tA})_{t \ge 0}$$ on a Hilbert space. First we study the long-time asymptotic behavior of the Cayley transform $$V_{\omega }(A) :=(A-\omega I) (A+\omega I)^{-1}$$ with $$\omega >0$$. We give a decay estimate for $$\Vert V_{\omega }(A)^nA^{-1}\Vert $$ when $$(e^{-tA})_{t \ge 0}$$ is polynomially stable. Considering the case where the parameter $$\omega $$ varies, we estimate $$\Vert (\prod _{k=1}^n V_{\omega _k}(A))A^{-1}\Vert $$ for exponentially stable $$C_0$$-semigroups $$(e^{-tA})_{t \ge 0}$$. Next we show that if the generator $$-A$$ of the bounded $$C_0$$-semigroup has a bounded inverse, then $$\sup _{t \ge 0} \Vert e^{-tA^{-1 } } A^{-\alpha } \Vert < \infty $$ for all $$\alpha >0$$. We also present an estimate for the rate of decay of $$\Vert e^{-tA^{-1 } } A^{-1} \Vert $$, assuming that $$(e^{-tA})_{t \ge 0}$$ is polynomially stable. To obtain these results, we use operator norm estimates offered by a functional calculus called the $$\mathcal {B}$$-calculus.

  Springer Science and Business Media LLC, 2024年05月, Journal of Evolution Equations, 24(2) (2), 1 - 34, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Decay of operator semigroups, infinite-time admissibility, and related resolvent estimates

  Masashi Wakaiki

  Elsevier BV, 2024年04月, Journal of Mathematical Analysis and Applications, 538(1) (1), 1 - 25, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• 複数の食事シナリオに対応可能な血糖値のTube-basedモデル予測制御

  飯村 由信, 若生 将史

  The Society of Instrument and Control Engineers, 2023年12月, 計測自動制御学会論文集, 59(12) (12), 529 - 541, 日本語

  [査読有り]

  研究論文（学術雑誌）


• Decay Rate of exp (A^{-1}t)A^{-1} on a Hilbert space and the Crank–Nicolson scheme with smooth initial data

  Masashi Wakaiki

  Abstract This paper is concerned with the decay rate of $$e^{A^{-1}t}A^{-1}$$ for the generator A of an exponentially stable $$C_0$$-semigroup on a Hilbert space. To estimate the decay rate of $$e^{A^{-1}t}A^{-1}$$, we apply a bounded functional calculus. Using this estimate and Lyapunov equations, we also study the quantified asymptotic behavior of the Crank-Nicolson scheme with smooth initial data. A similar argument is applied to a polynomially stable $$C_0$$-semigroup whose generator is normal.

  Springer Science and Business Media LLC, 2023年11月, Integral Equations and Operator Theory, 95(4) (4), 1 - 24, 英語

  [査読有り]

  研究論文（学術雑誌）


• Self‐triggered consensus of multi‐agent systems with quantized relative state measurements

  Masashi Wakaiki

  Abstract This paper addresses the consensus problem of first‐order continuous‐time multi‐agent systems over undirected graphs. Each agent samples relative state measurements in a self‐triggered fashion and transmits the sum of the measurements to its neighbours. Moreover, we use finite‐level dynamic quantizers and apply the zooming‐in technique. The proposed joint design method for quantization and self‐triggered sampling achieves asymptotic consensus, and inter‐event times are strictly positive. Sampling times are determined explicitly with iterative procedures including the computation of the Lambert W‐function. A simulation example is provided to illustrate the effectiveness of the proposed method.

  Institution of Engineering and Technology (IET), 2023年10月, IET Control Theory & Applications, 18(4) (4), 511 - 529, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• 利益関数の推定精度が高い統計モデルの構築

  飯村 由信, 若生 将史, 本間 克己, 梅田 裕平, 樋口 博之, 久保田 和己

  The Society of Instrument and Control Engineers, 2023年07月, 計測自動制御学会論文集, 59(7) (7), 330 - 341, 日本語

  [査読有り]

  研究論文（学術雑誌）


• Self-triggered resilient stabilization of linear systems with quantized outputs

  Wenjie Liu, Masashi Wakaiki, Jian Sun, Gang Wang, Jie Chen

  Elsevier BV, 2023年07月, Automatica, 153, 1 - 9, 英語, 国際共著している

  [査読有り]

  研究論文（学術雑誌）


• Robustness of polynomial stability with respect to sampling

  Masashi Wakaiki

  We provide a partially affirmative answer to the following question on robustness of polynomial stability with respect to sampling: “Suppose that a continuous-time state-feedback controller achieves the polynomial stability of the infinite-dimensional linear system. We apply an idealized sampler and a zero-order hold to a feedback loop around the controller. Then, is the sampled-data system strongly stable for all sufficiently small sampling periods? Furthermore, is the polynomial decay of the continuous-time system transferred to the sampled-data system under sufficiently fast sampling?” The generator of the open-loop system is assumed to be a Riesz-spectral operator whose eigenvalues are not on the imaginary axis but may approach it asymptotically. We provide conditions for strong stability to be preserved under fast sampling. Moreover, we estimate the decay rate of the state of the sampled-data system with a smooth initial state and a sufficiently small sampling period.

  EDP Sciences, 2023年06月, ESAIM: Control, Optimisation and Calculus of Variations, 29, 1 - 42, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Memory Saving State-Sharing Multi-Observer for a Class of Multi-Observer-Based Algorithms

  Michelle S. Chong, Masashi Wakaiki, João P. Hespanha

  Institute of Electrical and Electronics Engineers (IEEE), 2023年05月, IEEE Control Systems Letters, 7, 1772 - 1777, 英語, 国際共著している

  [査読有り]

  研究論文（学術雑誌）


• Self-triggered stabilization of discrete-time linear systems with quantized state measurements

  Masashi Wakaiki

  Institute of Electrical and Electronics Engineers (IEEE), 2023年03月, IEEE Transactions on Automatic Control, 68(3) (3), 1776 - 1783, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Secure communication systems based on synchronization of chaotic vibration of wave equations

  Hideki Sano, Masashi Wakaiki, Takaharu Yaguchi

  Research Institute of Signal Processing, Japan, 2022年11月, Journal of Signal Processing, 26(6) (6), 147 - 158, 英語

  [査読有り]

  研究論文（学術雑誌）


• Cell zooming with masked data for off-grid small cell networks: Distributed optimization approach

  Masashi Wakaiki, Katsuya Suto, Izumi Masubuchi

  Institute of Electrical and Electronics Engineers (IEEE), 2022年07月, IEEE Transactions on Control Systems Technology, 30(4) (4), 1696 - 1710, 英語

  [査読有り]

  研究論文（学術雑誌）


• Semi-uniform input-to-state stability of infinite-dimensional systems

  Masashi Wakaiki

  Abstract We introduce the notions of semi-uniform input-to-state stability and its subclass, polynomial input-to-state stability, for infinite-dimensional systems. We establish a characterization of semi-uniform input-to-state stability based on attractivity properties as in the uniform case. Sufficient conditions for linear systems to be polynomially input-to-state stable are provided, which restrict the range of the input operator depending on the rate of polynomial decay of the product of the semigroup and the resolvent of its generator. We also show that a class of bilinear systems are polynomially integral input-to-state stable under a certain smoothness assumption on nonlinear operators.

  Springer Science and Business Media LLC, 2022年06月, Mathematics of Control, Signals, and Systems, 34(4) (4), 789 - 817, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Synchronizing chaotic PDE system using backstepping and its application to image encryption

  Hideki Sano, Masashi Wakaiki

  Informa UK Limited, 2022年06月, SICE Journal of Control, Measurement, and System Integration, 15(2) (2), 182 - 190, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Quantized control of infinite-dimensional discrete-time systems with packet dropouts

  Masashi Wakaiki

  2022年05月, Proceedings of 13th Asian Control Conference, 1244 - 1245, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stability of infinite-dimensional sampled-data systems with unbounded control operators and perturbations

  Masashi Wakaiki

  Elsevier BV, 2022年04月, Systems & Control Letters, 162, 1 - 8, 英語

  [査読有り]

  研究論文（学術雑誌）


• Stability analysis of infinite-dimensional event-triggered and self-triggered control systems with Lipschitz perturbations

  Masashi Wakaiki, Hideki Sano

  <p style='text-indent:20px;'>This paper addresses the following question: "Suppose that a state-feedback controller stabilizes an infinite-dimensional linear continuous-time system. If we choose the parameters of an event/self-triggering mechanism appropriately, is the event/self-triggered control system stable under all sufficiently small nonlinear Lipschitz perturbations?" We assume that the stabilizing feedback operator is compact. This assumption is used to guarantee the strict positiveness of inter-event times and the existence of the mild solution of evolution equations with unbounded control operators. First, for the case where the control operator is bounded, we show that the answer to the above question is positive, giving a sufficient condition for exponential stability, which can be employed for the design of event/self-triggering mechanisms. Next, we investigate the case where the control operator is unbounded and prove that the answer is still positive for periodic event-triggering mechanisms.</p>

  American Institute of Mathematical Sciences (AIMS), 2022年03月, Mathematical Control and Related Fields, 12(1) (1), 245 - 273, 英語

  [査読有り]

  研究論文（学術雑誌）


• The Cayley transform of the generator of a polynomially stable C0-semigroup

  Masashi Wakaiki

  Abstract In this paper, we study the decay rate of the Cayley transform of the generator of a polynomially stable $$C_0$$-semigroup. To estimate the decay rate of the Cayley transform, we develop an integral condition on resolvents for polynomial stability. Using this integral condition, we relate polynomial stability to Lyapunov equations. We also study robustness of polynomial stability for a certain class of structured perturbations.

  Springer Science and Business Media LLC, 2021年12月, Journal of Evolution Equations, 21(4) (4), 4575 - 4597, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Strong stability of sampled-data Riesz-spectral systems

  Masashi Wakaiki

  Society for Industrial & Applied Mathematics (SIAM), 2021年10月, SIAM Journal on Control and Optimization, 59(5) (5), 3498 - 3523, 英語

  [査読有り]

  研究論文（学術雑誌）


• State estimation of Kermack–McKendrick PDE model with latent period and observation delay

  Hideki Sano, Masashi Wakaiki

  Institute of Electrical and Electronics Engineers (IEEE), 2021年10月, IEEE Transactions on Automatic Control, 66(10) (10), 4982 - 4989, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Secret communication systems using chaotic wave equations with neural network boundary conditions

  Yuhan Chen, Hideki Sano, Masashi Wakaiki, Takaharu Yaguchi

  In a secret communication system using chaotic synchronization, the communication information is embedded in a signal that behaves as chaos and is sent to the receiver to retrieve the information. In a previous study, a chaotic synchronous system was developed by integrating the wave equation with the van der Pol boundary condition, of which the number of the parameters are only three, which is not enough for security. In this study, we replace the nonlinear boundary condition with an artificial neural network, thereby making the transmitted information difficult to leak. The neural network is divided into two parts; the first half is used as the left boundary condition of the wave equation and the second half is used as that on the right boundary, thus replacing the original nonlinear boundary condition. We also show the results for both monochrome and color images and evaluate the security performance. In particular, it is shown that the encrypted images are almost identical regardless of the input images. The learning performance of the neural network is also investigated. The calculated Lyapunov exponent shows that the learned neural network causes some chaotic vibration effect. The information in the original image is completely invisible when viewed through the image obtained after being concealed by the proposed system. Some security tests are also performed. The proposed method is designed in such a way that the transmitted images are encrypted into almost identical images of waves, thereby preventing the retrieval of information from the original image. The numerical results show that the encrypted images are certainly almost identical, which supports the security of the proposed method. Some security tests are also performed. The proposed method is designed in such a way that the transmitted images are encrypted into almost identical images of waves, thereby preventing the retrieval of information from the original image. The numerical results show that the encrypted images are certainly almost identical, which supports the security of the proposed method.

  MDPI AG, 2021年07月, Entropy, 23(7) (7), 904 - 904, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Harvest-then-transmit-based TDMA protocol with statistical channel state information for wireless powered sensor networks

  Takeru Terauchi, Katsuya Suto, Masashi Wakaiki

  2021年04月, Proceedings of the 93rd IEEE Vehicular Technology Conference, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stabilization of networked control systems under DoS attacks and output quantization

  Masashi Wakaiki, Ahmet Cetinkaya, Hideaki Ishii

  This article addresses quantized output feedback stabilization under denial-of-service (DoS) attacks. First, assuming that the duration and frequency of DoS attacks are averagely bounded and that an initial bound of the plant state is known, we propose an output encoding scheme that achieves exponential convergence with finite data rates. Next, we show that a suitable state transformation allows us to remove the assumption on the DoS frequency. Finally, we discuss the derivation of state bounds under DoS attacks and obtain sufficient conditions on the bounds of DoS duration and frequency for achieving Lyapunov stability of the closed-loop system.

  IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2020年08月, IEEE Transactions on Automatic Control, 65(8) (8), 3560 - 3575, 英語

  [査読有り]

  研究論文（学術雑誌）


• Stability analysis of perturbed infinite-dimensional sampled-data systems

  Masashi Wakaiki, Yutaka Yamamoto

  2020年04月, Systems & Control Letters, 138, 1 - 8, 英語

  [査読有り]

  研究論文（学術雑誌）


• Event-triggered control of infinite-dimensional systems

  Masashi Wakaiki, Hideki Sano

  2020年02月, SIAM Journal on Control and Optimization, 58(2) (2), 605 - 635, 英語

  [査読有り]

  研究論文（学術雑誌）


• An LMI approach to stability analysis of coupled parabolic systems

  Masashi Wakaiki

  2020年01月, IEEE Transactions on Automatic Control, 65(1) (1), 404 - 411, 英語

  [査読有り]

  研究論文（学術雑誌）


• Sampled-data output regulation of well-posed infinite-dimensional systems with constant reference and disturbance signals

  Masashi Wakaiki, Hideki Sano

  2020年01月, Mathematics of Control, Signals, and Systems, 32(1) (1), 1 - 58, 英語

  [査読有り]

  研究論文（学術雑誌）


• Supervisory control of discrete-event systems under attacks

  Masashi Wakaiki, Paulo Tabuada, Joao P. Hespanha

  2019年12月, Dynamic Games and Applications, 9(4) (4), 965 - 983, 英語

  [査読有り]

  研究論文（学術雑誌）


• Optimal current control for PMSM considering inverter output voltage limit: Model predictive control and pulse width modulation

  Kenta Koiwa, Toru Kuribayashi, Tadanano Zanma, Kang-Zhi Liu, Masashi Wakaiki

  Institution of Engineering and Technology (IET), 2019年12月, IET Electric Power Applications, 13(12) (12), 2044 - 2051, 英語

  [査読有り]

  研究論文（学術雑誌）


• Privacy-preserved cell zooming with distributed optimization in green networks

  Masashi Wakaiki, Katsuya Suto, Izumi Masubuchi

  This paper addresses the problem of cell zooming in green networks. We apply a state-of-the-art methodology, distributed optimization, to solve the privacy-preserved cell zooming issue in green networks. To this end, we approximate the cell zooming problem by a certain convex problem. We also develop a data masking technique, under which we can still obtain a correct solution of the convex problem. The proposed method outperforms a Q-learning-based approach in terms of energy efficiency and the charging rate of batteries.

  Institute of Electrical and Electronics Engineers Inc., 2019年09月, IEEE Vehicular Technology Conference, 2019-, 英語

  研究論文（国際会議プロシーディングス）


• 非局所境界条件に無駄時間を含む1階双曲型システムに対するオブザーバ：誤差システムのL2-安定性

  佐野 英樹, 若生 将史, 丸山 颯天

  2019年09月, 計測自動制御学会論文集, 55(9) (9), 582 - 584, 日本語

  [査読有り]

  研究論文（学術雑誌）


• Boundary stabilization of first-order hyperbolic equations with input delay

  Hideki Sano, Masashi Wakaiki

  2019年07月, Japan Journal of Industrial and Applied Mathematics, 36(2) (2), 325 - 355, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Observer-based stabilization of systems with quantized inputs and outputs

  Masashi Wakaiki, Tadanao Zanma, Kang-Zhi Liu

  We study a stabilization problem for systems with quantized signals. We propose encoding strategies for three signals: the plant output, the control input, and the estimate of the plant output. A controller generates the estimate of the plant output in addition to the control input and then transmits their quantized data to a plant for control and quantization. We obtain sufficient conditions for local practical stability under bounded disturbances and noise. We first develop an encoding method for general stabilizing gains and then tailor it to deadbeat gains. Finally, we illustrate the proposed encoding methods with numerical simulations.

  IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019年07月, IEEE Transactions on Automatic Control, 64(7) (7), 2929 - 2936, 英語

  [査読有り]

  研究論文（学術雑誌）


• A control-theoretic approach for cell zooming of energy harvesting small cell networks

  Masashi Wakaiki, Katsuya Suto, Kenta Koiwa, Tadanao Zanma, Kang-Zhi Liu

  Institute of Electrical and Electronics Engineers (IEEE), 2019年06月, IEEE Transactions on Green Communications and Networking, 3(2) (2), 329 - 342, 英語

  [査読有り]

  研究論文（学術雑誌）


• Backstepping observers for two linearized Kermack-McKendrick models

  Hideki Sano, Masashi Wakaiki, Hayate Maruyama

  2018年10月, Proceedings of the 17th IFAC Workshop on Control Applications of Optimization, 456 - 461, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stabilization of networked control systems under clock offsets and quantization

  Kunihisa Okano, Masashi Wakaiki, Guosong Yang, Joao P. Hespanha

  This paper studies the impact of clock mismatches and quantization on networked control systems. We consider a scenario where the plant's state is measured by a sensor that communicates with the controller through a network. Variable communication delays and clock jitter do not permit a perfect synchronization between the clocks of the sensor and controller. We investigate limitations on the clock offset tolerable for stabilization of the feedback system. For a process with a scalar-valued state, we show that there exists a tight bound on the offset above which the closed-loop system cannot be stabilized with any causal controllers. For higher dimensional plants, if the plant has two distinct poles, then the effect of clock mismatches can be canceled with a finite number of measurements, and hence there is no fundamental limitation. We also consider the case where the measurements are subject to quantization in addition to clock mismatches. For first-order plants, we present necessary conditions and sufficient conditions for stabilizability, which show that a larger clock offset requires a finer quantization.

  Institute of Electrical and Electronics Engineers Inc., 2018年06月, IEEE Transactions on Automatic Control, 63(6) (6), 1618 - 1633, 英語

  [査読有り]

  研究論文（学術雑誌）


• Simultaneous optimization of statistical model and control input plan

  Yoshinobu Iimura, Masashi Wakaiki, Katsumi Homma, Yuhei Umeda, Junji Kaneko, Hiroyuki Higuchi, Kazumi Kubota, Naoya Asami, Kazuto Ikeda

  2018年06月, Proceedings of the 2018 American Control Conference, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Quantized output feedback stabilization under DoS attacks

  Masashi Wakaiki, Ahmet Cetinkaya, Hideaki Ishii

  2018年06月, Proceedings of the 2018 American Control Conference, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Model predictive cell zooming for energy-harvesting small cell networks

  Masashi Wakaiki, Katsuya Suto, Kenta Koiwa, Tadanao Zanma, Kang-Zhi Liu

  2018年05月, Proceedings of the IEEE International Conference on Communications 2018, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stability analysis and l2-gain of adaptive control systems with event-triggered try-once-discard protocols

  Masashi Wakaiki

  2018年01月, IEEE Control Systems Letters, 2(1) (1), 157 - 162, 英語

  [査読有り]

  研究論文（学術雑誌）


• LQ-Optimal Sampled-Data Control under Stochastic Delays: Gridding Approach for Stabilizability and Detectability.

  Masashi Wakaiki, Masaki Ogura, João P. Hespanha

  2018年, SIAM J. Control and Optimization, 56(4) (4), 2634 - 2661, 英語

  [査読有り]

  研究論文（学術雑誌）


• Stabilization of switched systems with sampled and quantized output feedback

  Masashi Wakaiki, Yutaka Yamamoto

  2017年12月, IET Control Theory and Applications, 11(12) (12), 1913 - 1921, 英語

  [査読有り]

  研究論文（学術雑誌）


• H∞制御による電力貯蔵装置の容量低減化

  小岩 健太, 鈴木 賢太, 劉 康志, 残間 忠直, 若生 将史, 田村 淳二

  2017年08月, 電気学会論文誌Ｂ（電力・エネルギー部門誌）, 137(8) (8), 596 - 597, 日本語

  [査読有り]

  研究論文（学術雑誌）


• Stabilization of systems with asynchronous sensors and controllers

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  We study the stabilization of networked control systems with asynchronous sensors and controllers. Offsets between the sensor and controller clocks are unknown and modeled as parametric uncertainty. First we consider multi-input linear systems and provide a sufficient condition for the existence of linear time-invariant controllers that are capable of stabilizing the closed-loop system for every clock offset in a given range of admissible values. For first-order systems, we next obtain the maximum length of the offset range for which the system can be stabilized by a single controller. Finally we illustrate the results with a numerical simulation. (C) 2017 Elsevier Ltd. All rights reserved.

  PERGAMON-ELSEVIER SCIENCE LTD, 2017年07月, Automatica, 81(7) (7), 314 - 321, 英語

  [査読有り]

  研究論文（学術雑誌）


• Stability and performance analysis of receding horizon quantizer in single-input system

  Syuntaro Takayasu, Tadanao Zanma, Masashi Wakaiki, Kang-Zhi Liu

  2017年07月, Proceedings of the 36th Chinese Control Conference, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Quantized Output Feedback Stabilization by Luenberger Observer

  Masashi Wakaiki, Tadanao Zanma, Kang-Zhi Liu

  2017年07月, Proceedings of the 20th IFAC World Congress, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Design of Networked Control Systems in Consideration of quantization error and channel capacity

  Guangbo Li, Tadanao Zanma, Masashi Wakaiki, Kang-Zhi Liu

  2017年07月, Proceedings of the 36th Chinese Control Conference, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stabilization of Switched Linear Systems With Quantized Output and Switching Delays

  Masashi Wakaiki, Yutaka Yamamoto

  This paper addresses the problem of designing time-varying quantizers for the stabilization of switched linear systems with quantized output and switching delays. The detection delays of switches are assumed to be time-varying but bounded, and the dwell time of the switching signal is assumed to be larger than the maximum delay. Given a switching controller, we analyze reachable sets of the closed-loop state by using a common Lyapunov function and then construct a quantizer that guarantees asymptotic stability. A sufficient condition for the existence of such a quantizer is characterized by the maximum switching delay and the dwell time.

  IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2017年06月, IEEE Transactions on Automatic Control, 62(6) (6), 2958 - 2964, 英語

  [査読有り]

  研究論文（学術雑誌）


• Delayed bet-hedging resilience strategies under environmental fluctuations

  Masaki Ogura, Masashi Wakaiki, Harvey Rubin, Victor M. Preciado

  Many biological populations, such as bacterial colonies, have developed through evolution a protection mechanism, called bet hedging, to increase their probability of survival under stressful environmental fluctuation. In this context, the concept of preadaptation refers to a common type of bet-hedging protection strategy in which a relatively small number of individuals in a population stochastically switch their phenotypes to a dormant metabolic state in which they increase their probability of survival against potential environmental shocks. Hence, if an environmental shock took place at some point in time, preadapted organisms would be better adapted to survive and proliferate once the shock is over. In many biological populations, the mechanisms of preadaptation and proliferation present delays whose influence in the fitness of the population are not well understood. In this paper, we propose a rigorous mathematical framework to analyze the role of delays in both preadaptation and proliferation mechanisms in the survival of biological populations, with an emphasis on bacterial colonies. Our theoretical framework allows us to analytically quantify the average growth rate of a bet-hedging bacterial colony with stochastically delayed reactions with arbitrary precision. We verify the accuracy of the proposed method by numerical simulations and conclude that the growth rate of a bet-hedging population shows a nontrivial dependency on their preadaptation and proliferation delays. Contrary to the current belief, our results show that faster reactions do not, in general, increase the overall fitness of a biological population.

  AMER PHYSICAL SOC, 2017年05月, PHYSICAL REVIEW E, 95(5) (5), 1 - 8, 英語

  [査読有り]

  研究論文（学術雑誌）

  神戸大学リポジトリ（Kernel）へのリンク


• Estimation of network traffic status for networked control systems with data dropout and its control

  Daiki Hashimoto, Tadanao Zanma, Masashi Wakaiki, Kang-Zhi Liu

  2017年02月, Proceedings of the 5th International Conference on System Modeling and Optimization, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Linear quadratic control for sampled-data systems with stochastic delays.

  Masashi Wakaiki, Masaki Ogura, João Pedro Hespanha

  IEEE, 2017年, Proceedings of the 2017 American Control Conference, 1978 - 1983, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Dynamic analysis of bet-hedging strategies as a protection mechanism against environmental fluctuations

  Masaki Ogura, Masashi Wakaiki, Victor M. Preciado

  © 2016 IEEE. In order to increase their robustness against environmental fluctuations, many biological populations have developed bet-hedging mechanisms in which the population 'bets' against the presence of prolonged favorable environmental conditions by having a few individual behaving as if they sensed a threatening or stressful environment. As a result, the population (as a whole) increases its chances of surviving environmental fluctuations in the long term, while sacrificing short-term performance. In this paper, we propose a theoretical framework, based on Markov jump linear systems, to model and evaluate the performance of bet-hedging strategies in the presence of stochastic fluctuations. We illustrate our results using numerical simulations.

  2016年12月, 2016 IEEE 55th Conference on Decision and Control, CDC 2016, 4178 - 4183, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stability analysis of sampled-data switched systems with quantization

  Masashi Wakaiki, Yutaka Yamamoto

  We propose a stability analysis method for sampled-data switched linear systems with finite-level static quantizers. In the closed-loop system, information on the active mode of the plant is transmitted to the controller only at each sampling time. This limitation of switching information leads to a mode mismatch between the plant and the controller, and the system may become unstable. A mode mismatch also makes it difficult to find an attractor set to which the state trajectory converges. A switching condition for stability is characterized by the total time when the modes of the plant and the controller are different. Under this condition, we derive an ultimate bound on the state trajectories by using a common Lyapunov function computed from a randomized algorithm. The switching condition can be reduced to a dwell-time condition. (C) 2016 Elsevier Ltd. All rights reserved.

  PERGAMON-ELSEVIER SCIENCE LTD, 2016年07月, AUTOMATICA, 69(7) (7), 157 - 168, 英語

  [査読有り]

  研究論文（学術雑誌）


• SMT-Based Observer Design for Cyber-Physical Systems Under Sensor Attacks

  Yasser Shoukry, Michelle Chong, Masashi Wakaiki, Pierluigi Nuzzo, Alberto L. Sangiovanni-Vincentelli, Sanjit A. Seshia, Joao P. Hespanha, Paulo Tabuada

  We introduce a scalable observer architecture to estimate the states of a discrete-time linear-time-invariant (LTI) system whose sensors can be manipulated by an attacker. Given the maximum number of attacked sensors, we build on previous results on necessary and sufficient conditions for state estimation, and propose a novel multi-modal Luenberger (MML) observer based on efficient Satisfiability Modulo Theory (SMT) solving. We present two techniques to reduce the complexity of the estimation problem. As a first strategy, instead of a bank of distinct observers, we use a family of filters sharing a single dynamical equation for the states, but different output equations, to generate estimates corresponding to different subsets of sensors. Such an architecture can reduce the memory usage of the observer from an exponential to a linear function of the number of sensors. We then develop an efficient SMT-based decision procedure that is able to reason about the estimates of the MML observer to detect at runtime which sets of sensors are attack-free, and use them to obtain a correct state estimate. We provide proofs of convergence for our algorithm and report simulation results to compare its runtime performance with alternative techniques. Our algorithm scales well for large systems (including up to 5000 sensors) for which many previously proposed algorithms are not implementable due to excessive memory and time requirements. Finally, we illustrate the effectiveness of our algorithm on the design of resilient power distribution systems.

  IEEE, 2016年, 2016 ACM/IEEE 7TH INTERNATIONAL CONFERENCE ON CYBER-PHYSICAL SYSTEMS (ICCPS), 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• L-2-Gain Analysis of Systems with Clock Offsets

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  In this paper, we analyze the L-2-gain of sampleddata systems with asynchronous sensing and control. The closed-loop system has time-varying clock offsets and sampling intervals and can be modeled as a parameter-uncertain system. We use a lifting approach and a gridding and norm-bounded approach in order to analyze intersample behavior and deal with parameter uncertainty, respectively. An upper bound on the L-2-gain is derived via linear matrix inequalities. We illustrate the proposed method by applying it to an active suspension system.

  IEEE, 2016年, 2016 AMERICAN CONTROL CONFERENCE (ACC), 4239 - 4244, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• L-2-Gain Analysis of Regenerative Switched Linear Systems with Sampled-Data State-Feedback Control

  Masaki Ogura, Masashi Wakaiki, Joao P. Hespanha, Victor M. Preciado

  In this paper, we analyze the L-2-gain of a class of switched linear systems under sampled-data state-feedback control. We consider switched linear systems whose switching signal is a regenerative process. Using the lifting approach and piecewise-constant approximations, we derive a sequence whose limit inferior upper-bounds the L-2-gain of the closed-loop system. Each term of the sequence can be found by solving a linear matrix inequality. We illustrate the results by the L-2-gain analysis of a linear system with a failure-prone controller.

  IEEE, 2016年, 2016 AMERICAN CONTROL CONFERENCE (ACC), 709 - 714, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Electrical angle estimation of rotor for PMSM in model predictive current control

  Yu Takagi, Satoshi Tozawa, Kenta Koiwa, Tadanao Zanma, Masashi Wakaiki, Kang Zhi Liu, Yasuaki Aoki, Hideji Yoshida, Masami Fujitsuna

  This paper presents a method for estimating the electrical angle of the rotor for permanent-magnet synchronous motors (PMSMs) in model predictive current control (MPCC) so that an encoder is removed for high reliability and low system costs. In our approach, an estimator of the electrical angle of the rotor is introduced in the MPCC. The effectiveness of the proposed method is verified through simulations and experiments.

  IEEE, 2016年, 2016 19TH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES AND SYSTEMS (ICEMS 2016), 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Robust Stability under Asynchronous Sensing and Control

  Masashi Wakaiki, Masaki Ogura, Joao P. Hespanha

  We address the stability of networked control systems in which a sensor and an output-feedback controller operate asynchronously, which leads to uncertainty in the sampling instants. In addition, we also consider polytopic uncertainty in the plant model. The analysis is based on transforming the closed-loop system into an impulsive system, by considering an extended state variable that includes the states of the continuous-time plant and the discrete-time controller. We provide a sufficient condition for the robust stability of the closed-loop system in terms of linear matrix inequalities. This condition is based on the construction of a continuous-time Lyapunov functional that also incorporates the discrete-time state of the digital controller. We illustrate the obtained result with numerical simulations.

  IEEE, 2016年, 2016 IEEE 55TH CONFERENCE ON DECISION AND CONTROL (CDC), 5962 - 5967, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• SMT-Based Observer Design for Cyber-Physical Systems Under Sensor Attacks

  Yasser Shoukry, Michelle Chong, Masashi Wakaiki, Pierluigi Nuzzo, Alberto L. Sangiovanni-Vincentelli, Sanjit A. Seshia, Joao P. Hespanha, Paulo Tabuada

  We introduce a scalable observer architecture to estimate the states of a discrete-time linear-time-invariant (LTI) system whose sensors can be manipulated by an attacker. Given the maximum number of attacked sensors, we build on previous results on necessary and sufficient conditions for state estimation, and propose a novel multi-modal Luenberger (MML) observer based on efficient Satisfiability Modulo Theory (SMT) solving. We present two techniques to reduce the complexity of the estimation problem. As a first strategy, instead of a bank of distinct observers, we use a family of filters sharing a single dynamical equation for the states, but different output equations, to generate estimates corresponding to different subsets of sensors. Such an architecture can reduce the memory usage of the observer from an exponential to a linear function of the number of sensors. We then develop an efficient SMT-based decision procedure that is able to reason about the estimates of the MML observer to detect at runtime which sets of sensors are attack-free, and use them to obtain a correct state estimate. We provide proofs of convergence for our algorithm and report simulation results to compare its runtime performance with alternative techniques. Our algorithm scales well for large systems (including up to 5000 sensors) for which many previously proposed algorithms are not implementable due to excessive memory and time requirements. Finally, we illustrate the effectiveness of our algorithm on the design of resilient power distribution systems.

  IEEE, 2016年, 2016 ACM/IEEE 7TH INTERNATIONAL CONFERENCE ON CYBER-PHYSICAL SYSTEMS (ICCPS), 2(1) (1), 1 - 27, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Real-time control under clock offsets between sensors and controllers

  Kunihisa Okano, Masashi Wakaiki, Joao P. Hespanha

  2015年04月, Proceedings of the 18th International Conference on Hybrid Systems: Computation and Control, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stabilization of Networked Control Systems with Clock Offsets

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  We consider the stabilization of networked control systems with time-invariant clock offsets between the sensors and the controllers. Clock offsets are modeled as parametric uncertainty and we provide necessary and sufficient conditions for the existence of a single controller that is capable of stabilizing the closed loop for every clock offset in a given range. For scalar systems, we obtain the maximum length of the offset interval for which the system can be stabilized by a single linear time-invariant controller. We compare the offset bounds that would be allowed by specific classes of controllers for scalar systems.

  IEEE, 2015年, 2015 AMERICAN CONTROL CONFERENCE (ACC), 3522 - 3527, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Observability of linear systems under adversarial attacks

  Michelle S. Chong, Masashi Wakaiki, Joao P. Hespanha

  We address the problem of state estimation for multi-output continuous-time linear systems, for which an attacker may have control over some of the sensors and inject (potentially unbounded) additive noise into some of the measured outputs. To characterize the resilience of a system against such sensor attacks, we introduce a new notion of observability - termed "observability under attacks" - that addresses the question of whether or not it is possible to uniquely reconstruct the state of the system by observing its inputs and outputs over a period of time, with the understanding that some of the available system's outputs may have been corrupted by the opponent. We provide computationally efficient tests for observability under attacks that amount to testing the (standard) observability for an appropriate finite set of systems. In addition, we propose two state estimation algorithms that permit the state reconstruction in spite of the attacks. One of these algorithms uses observability Gramians and a finite window of measurements to reconstruct the initial state. The second algorithm takes the form of a switched observer that asymptotically converges to the correct state estimate in the absence of additive noise and disturbances, or to a neighborhood of the correct state estimate in the presence of bounded noise and disturbances.

  IEEE, 2015年, 2015 AMERICAN CONTROL CONFERENCE (ACC), 2439 - 2444, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stabilization of Discrete-time Piecewise Affine Systems with Quantized Signals

  Masashi Wakaiki, Yutaka Yamamoto

  This paper studies quantized control for discrete-time piecewise affine systems. For given stabilizing feedback controllers, we propose an encoding strategy for local stability. If the quantized state is near the boundaries of quantization regions, then the controller can recompute a better quantization value. For the design of quantized feedback controllers, we also consider the stabilization of piecewise affine systems with bounded disturbances. In order to derive a less conservative design method with low computational cost, we investigate a region to which the state belong in the next step.

  IEEE, 2015年, 2015 54TH IEEE CONFERENCE ON DECISION AND CONTROL (CDC), 1601 - 1606, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Control under Clock Offsets and Actuator Saturation

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  This paper studies the stability analysis and the stabilization problem for systems with asynchronous sensors and controllers, and actuators subject to saturation. We consider systems with parameter uncertainties caused by clock offsets. By using a polytopic overapproximation, we investigate how large clock offsets affect stability. In addition, we employ a sector characterization approach to address actuator saturation. We see from a numerical study that the range of allowable clock offset bounds drops if the saturation limit becomes smaller than a certain value.

  IEEE, 2015年, 2015 54TH IEEE CONFERENCE ON DECISION AND CONTROL (CDC), 6886 - 6891, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Output Feedback Stabilization of Switched Linear Systems with Limited Information

  Masashi Wakaiki, Yutaka Yamamoto

  We propose an encoding and control strategy for the stabilization of switched systems with limited information, supposing the controller is given for each mode. Only the quantized output and the active mode of the plant at each sampling time are transmitted to the controller. Due to switching, the active mode of the plant may be different from that of the controller in the closed-loop system. Hence if switching occurs, the quantizer must recalculate a bounded set containing the estimation error for quantization at the next sampling time. We establish the global asymptotic stability under a slow-switching assumption on dwell time and average dwell time. To this end, we construct multiple discrete-time Lyapunov functions with respect to the estimated state and the size of the bounded set.

  IEEE, 2014年12月, Proceedings of the 53rd IEEE Conference on Decision and Control, 3892 - 3897, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Stable controller design for mixed sensitivity reduction of infinite-dimensional systems

  Masashi Wakaiki, Yutaka Yamamoto

  In this paper we study the design of stable controllers for mixed sensitivity reduction for systems that have input/output delays and infinitely many unstable zeros. The proposed method is based on interpolation with a unit in H-infinity, which gives a necessary and sufficient condition for stabilization by stable controllers. Using the Youla parameterization, we introduce a two-block problem for the stable H-infinity controller design. The two-block problem is then transformed to a one-block problem solvable by the skew Toeplitz approach. (C) 2014 Elsevier B.V. All rights reserved.

  ELSEVIER SCIENCE BV, 2014年10月, Systems & Control Letters, 72(10) (10), 80 - 85, 英語

  [査読有り]

  研究論文（学術雑誌）


• Quantized feedback stabilization of sampled-data switched linear systems

  Masashi Wakaiki, Yutaka Yamamoto

  We propose a stability analysis method for sampled-data linear systems with quantization. The available information to the controller is limited: the quantized state and switching signal at each sampling time. Switching between sampling times can produce the mismatch of the modes between the plant and the controller. Moreover, the coarseness of quantization makes the trajectory wander around, not approach, the origin. Hence the trajectory nay leave the desired neighborhood if the mismatch leads to instability of the closed-loop system. For the stability of the switched systems, we develop a sufficient condition characterized by the total mismatch time. The relationship between the mismatch time the dwell time of the switching signal is also discussed.

  ELSEVIER SCIENCE BV, 2014年08月, Proceedings of the 19th IFAC World Congress, 9979 - 9984, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Quantized output feedback stabilization of switched linear systems

  Masashi Wakaiki, Yutaka Yamamoto

  2014年07月, Proceedings of the 21st International Symposium on Mathematical Theory of Networks and Systems, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Sensitivity Reduction by Stable Controllers for MIMO Infinite Dimensional Systems via the Tangential Nevanlinna-Pick Interpolation

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Ozbay

  We study the problem of finding a stable stabilizing controller that satisfies a desired sensitivity level for an MIMO infinite dimensional system. The systems we consider have finitely many simple transmission zeros in (C) over bar (+), but they are allowed to possess infinitely many poles in C+. We compute both upper and lower bounds of the minimum sensitivity achievable by a stable controller via the tangential Nevanlinna-Pick interpolation. We also obtain stable controllers attaining such an upper bound. To illustrate the results, we discuss a repetitive control system as an application of the proposed method.

  IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2014年04月, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 59(4) (4), 1099 - 1105, 英語

  [査読有り]

  研究論文（学術雑誌）


• Stable controllers for robust stabilization of systems with infinitely many unstable poles

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Özbay

  This paper studies the problem of robust stabilization by a stable controller for a linear time-invariant single-input single-output infinite dimensional system. We consider a class of plants having finitely many simple unstable zeros but possibly infinitely many unstable poles. First we show that the problem can be reduced to an interpolation-minimization by a unit element. Next, by the modified Nevanlinna-Pick interpolation, we obtain both lower and upper bounds on the multiplicative perturbation under which the plant can be stabilized by a stable controller. In addition, we find stable controllers to provide robust stability. We also present a numerical example to illustrate the results and apply the proposed method to a repetitive control system. © 2013 Elsevier B.V. All rights reserved.

  2013年, Systems and Control Letters, 62(6) (6), 511 - 516, 英語

  [査読有り]

  研究論文（学術雑誌）


• Mixed Sensitivity Reduction for Time-Delay Systems by Stable Controllers

  Masashi Wakaiki, Yutaka Yamamoto

  This paper studies the mixed sensitivity problem within the framework of strong stabilization. We consider a class of time-delay systems having only a finite number of unstable poles. However the systems are allowed to possess pure delays and infinitely many unstable zeros. The new solution we propose here is rooted in an operator-theoretic approach to interpolation to address the infinite dimensionality. First we give a sufficient condition for sensitivity reduction by a stable controller. Next, using this condition, we introduce a two-block problem for the design of stable controllers achieving both low sensitivity and robust stability. Finally we transform the twoblock problem to a one-block problem, which can be solved by matrix computations only. We also present numerical examples to illustrate the effectiveness of the proposed method.

  IEEE, 2013年, 2013 IEEE 52ND ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC), 1065 - 1070, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Sensitivity Reduction by Strongly Stabilizing Controllers for MIMO Distributed Parameter Systems

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Oezbay

  This note investigates a sensitivity reduction problem by stable stabilizing controllers for a linear time-invariant multi-input multioutput distributed parameter system. The plant we consider has finitely many unstable zeros, which are simple and blocking, but can possess infinitely many unstable poles. We obtain a necessary condition and a sufficient condition for the solvability of the problem, using the matrix Nevanlinna-Pick interpolation with boundary conditions. We also develop a necessary and sufficient condition for the solvability of the interpolation problem, and show an algorithm to obtain the solutions. Our method to solve the interpolation problem is based on the Schur-Nevanlinna algorithm.

  IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2012年08月, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 57(8) (8), 2089 - 2094, 英語

  [査読有り]

  研究論文（学術雑誌）


• Robust stabilization for distributed parameter systems by stable controllers

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Ozbay

  2012年07月, Proceedings of the 20th International Symposium on Mathematical Theory of Networks and Systems, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）


• Tangential Nevanlinna-Pick Interpolation for Strong Stabilization of MIMO Distributed Parameter Systems

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Ozbay

  We study the problem of finding stable controllers that stabilize a multi-input multi-output distributed parameter system while simultaneously reducing the sensitivity of the system. The plants we consider have finitely many unstable transmission zeros, but they can possess infinitely many unstable poles. Using the tangential Nevanlinna-Pick interpolation with boundary conditions, we obtain both upper and lower bounds of the minimum sensitivity that can be achieved by stable controllers. We also derive a method to find stable controllers for sensitivity reduction. In addition, we apply the proposed method to a repetitive control system.

  IEEE, 2012年, 2012 IEEE 51ST ANNUAL CONFERENCE ON DECISION AND CONTROL (CDC), 1584 - 1590, 英語

  [査読有り]

  研究論文（国際会議プロシーディングス）

• 「制御とネットワークが交差する数理的研究」特集号を企画して

  若生将史

  2024年06月, システム/制御/情報, 68(6) (6), 205 - 205, 日本語

  記事・総説・解説・論説等（その他）


• 書評：佐藤一宏著 線形代数を基礎とする応用数理入門 最適化理論・システム制御理論を中心に

  若生将史

  2024年05月, 数理科学, 62(6) (6), 66 - 66, 日本語

  書評論文,書評,文献紹介等


• The 25th International Symposium on Mathematical Theory of Networks and Systemsに参加して

  若生 将史

  2023年03月, システム／制御／情報, 67(3) (3), 127 - 127, 日本語

  会議報告等


• 分布定数系のカオスとその応用について

  佐野英樹, 若生将史, 谷口 隆晴

  2021年08月, システム/制御/情報, 65(8) (8), 305 - 310, 日本語

  [査読有り]

  記事・総説・解説・論説等（学術雑誌）


• 強連続半群と制御理論

  若生将史, 佐野英樹

  2021年06月, 計測と制御, 60(6) (6), 369 - 374, 日本語

  [査読有り]

  記事・総説・解説・論説等（学術雑誌）


• イベントトリガ制御の基礎

  若生 将史

  2019年11月, システム/制御/情報, 63(11) (11), 455 - 460, 日本語

  [査読有り]

  記事・総説・解説・論説等（学術雑誌）


• ネットワーク化制御系におけるデータ欠落の推定と制御

  残間 忠直, 橋本 大輝, 若生 将史, 劉康志

  公益社団法人 計測自動制御学会, 2017年07月, 計測と制御, 56(7) (7), 486 - 491, 日本語

  [査読有り]

  記事・総説・解説・論説等（学術雑誌）


• 同期誤差を考慮したネットワーク化制御

  若生 将史, 岡野訓尚

  公益社団法人 計測自動制御学会, 2016年11月, 計測と制御, 55(11) (11), 984 - 989, 日本語

  [査読有り]

  記事・総説・解説・論説等（学術雑誌）


• むだ時間系に対する安定なロバストコントローラの設計

  若生 将史

  公益社団法人 計測自動制御学会, 2014年11月, 計測と制御, 53(11) (11), 1048 - 1048, 日本語

  [査読有り]

  記事・総説・解説・論説等（学術雑誌）

• ネットワーク化制御

  永原正章, 岡野訓尚, 小蔵正輝, 若生将史

  共著, コロナ社, 2019年08月

• Semi-uniform ISS and iISS of infinite-dimensional systems

  Masashi Wakaiki

  Online Seminar on Input-to-State Stability and its Applications, 2023年08月, 英語

  [招待有り]

  口頭発表（招待・特別）


• LMI-based stability analysis of coupled multi-dimensional parabolic PDEs

  Masashi Wakaiki

  IFAC WC 2023 Workshop ''A Showcase of LMI-Based Methods for Analysis, Control and Estimation of PDEs, 2023年07月, 英語

  [招待有り]

  口頭発表（招待・特別）


• 安定な強連続半群の有理関数近似の減衰率

  若生 将史

  2022年度 応用数学合同研究集会, 2022年12月, 日本語

  口頭発表（一般）


• On Semi-uniform input-to-state stability and polynomial input-to-state stability

  Masashi Wakaiki

  25th International Symposium on Mathematical Theory of Networks and Systems, 2022年09月, 英語

  口頭発表（一般）


• Cell zooming with masked data for off-grid small cell networks: Distributed optimization approach

  Masashi Wakaiki, Katsuya Suto, Izumi Masubuchi

  6th IEEE Conference on Control Technology and Applications, 2022年08月, 英語

  口頭発表（一般）


• 無限次元システムの事象駆動型 ・自己駆動型制御

  若生将史

  第9回制御部門マルチシンポジウム ワークショップ「DX 時代のイベントベースト制御理論 ：異分野との架橋」, 2022年03月, 日本語

  シンポジウム・ワークショップパネル（指名）


• 食事シナリオを考慮した血糖値のロバストモデル予測制御

  飯村 由信, 若生 将史

  2022年電子情報通信学会総合大会, 2022年03月, 日本語

  口頭発表（一般）


• 入出力依存の重みを用いたモデル予測型血糖値制御

  飯村 由信, 若生 将史

  第8回計測自動制御学会制御部門マルチシンポジウム, 2021年03月, 日本語

  口頭発表（一般）


• 無限次元系のサンプル値制御

  若生 将史

  大阪大学MMDモデリング部門主催ワークショップ「工学と数学の接点を求めて」, 2020年11月

  シンポジウム・ワークショップパネル（指名）


• DoS攻撃の下での無限次元システムの量子化制御

  若生 将史

  第63回自動制御連合講演会, 2020年11月

  口頭発表（一般）


• Robustness of strong stability with respect to sampling

  若生 将史

  2020年度 日本数学会秋季総合分科会, 2020年09月, 日本語

  口頭発表（一般）


• 潜伏期間と観測遅れを伴うKermack-McKendrick モデルに対する状態推定

  佐野 英樹, 若生 将史

  第64回システム制御情報学会研究発表講演会, 2020年05月

  口頭発表（一般）


• 無限次元系に対する自己駆動制御

  若生将史, 佐野英樹

  第64回システム制御情報学会研究発表講演会, 2020年05月

  口頭発表（一般）


• 無限次元系のイベント駆動制御について

  若生 将史, 佐野 英樹

  2019年度 応用数学合同研究集会, 2019年12月, 日本語

  口頭発表（一般）


• 観測遅れを伴う Kermack-McKendrick モデルに対する状態推定

  佐野 英樹, 若生 将史

  2019年度 応用数学合同研究集会, 2019年12月, 日本語

  口頭発表（一般）


• 非局所境界条件にむだ時間を含む1階双曲型システムに対するオブザーバ設計と誤差システムのL2-安定性

  丸山 颯天, 佐野 英樹, 若生 将史

  第6回計測自動制御学会制御部門マルチシンポジウム, 2019年03月, 日本語, 国内会議

  ポスター発表


• 無限次元システムのサンプル値サーボ問題について

  若生 将史, 佐野 英樹

  2018年度 応用数学合同研究集会, 2018年12月, 日本語, 国内会議

  口頭発表（一般）


• 境界入力に無駄時間要素を含む1階双曲型システムの安定化について

  佐野 英樹, 若生 将史

  2018年度 応用数学合同研究集会, 2018年12月, 日本語, 大津, 国内会議

  口頭発表（一般）


• Q-Learning based Cell Zooming for Energy-Harvesting Small Cell Networks

  Katsuya Suto, Masashi Wakaiki

  IEICE Smartcom 2018, 2018年10月, 英語, 国際会議

  ポスター発表


• 非局所境界条件にむだ時間を含む双曲型システムに対する状態推定

  丸山 颯天, 佐野 英樹, 若生 将史

  日本応用数理学会2018年 年会, 2018年09月, 日本語, 名古屋, 国内会議

  口頭発表（一般）


• Event-triggered control systems

  Masashi Wakaiki

  SICE Annual Conference 2018 Workshop ''New Trends in Networked Control', 2018年09月, 英語, 国際会議

  シンポジウム・ワークショップパネル（指名）


• DoS攻撃の下での量子化制御

  若生 将史, Ahmet Cetinkaya, 石井 秀明

  第61回システム制御情報学会研究発表講演会, 2018年05月, 日本語, 国内会議

  口頭発表（一般）

• IEEE


• システム制御情報学会


• 日本応用数理学会


• 日本数学会


• 計測自動制御学会

• 無限次元デジタル制御系のための解析・設計理論の構築

  若生 将史

  日本学術振興会, 科学研究費助成事業, 基盤研究(C), 神戸大学, 2024年04月 - 2029年03月, 研究代表者


• 無限次元サンプル値系のロバスト安定性解析

  若生 将史

  日本学術振興会, 科学研究費助成事業 若手研究, 若手研究, 神戸大学, 2020年04月01日 - 2024年03月31日

  2021年度は，制御作用素が非有界である無限次元線形サンプル値系を対象とし，非有界摂動に対するロバスト安定性解析について研究を行った．非有界な制御作用素は，偏微分方程式系の境界制御問題を抽象的発展方程式の枠組みで表現する際に必要となる．一般に，制御作用素が入力空間から状態空間への有界作用素であるときに，その制御作用素は有界であるという．これに対して本研究では，状態空間を内包する外挿空間を考え，入力空間から外挿空間への有界作用素として制御作用素が与えられる場合を考えた． また非有界な摂動として，Desch-Shappacher型の摂動を取り扱った．偏微分方程式系の境界条件に摂動が加わった場合，その系を抽象的発展方程式に書き直すと，境界条件の摂動はDesch-Shappacher型の摂動となる．また，個体群動態に関する微分方程式や遅延微分方程式の解析にもDesch-Shappacher型の摂動が用いられることがある．Desch-Shappacher型の摂動が持つ非有界性は，上で述べた制御作用素と同様（状態空間から）外挿空間への作用素であることに由来する． 本研究の困難は，制御作用素と摂動の非有界性が複合的に系のダイナミクスに影響を与える点である．実際，制御作用素の終集合である外挿空間は系の生成作用素に依存するが，その生成作用素は摂動によって変化してしまう．まずDesch-Shappacher型の摂動によって外挿空間が変化しないことを示した．次に，生成作用素のレゾルベントが外挿空間から状態空間への有界作用素であることを利用して，サンプリング時刻間での状態の遷移を表す作用素が摂動によってどのように変化するか解析した．この解析により，Desch-Shappacher型の摂動が十分小さければ，サンプル値系の指数安定性が保存されることを明らかにした．


• サイバー攻撃に対して頑強な制御システムの開発

  若生 将史

  学術研究助成基金助成金／若手研究(B), 2017年04月 - 2020年03月, 研究代表者

  競争的資金


• 安定なコントローラによる分布定数系のＨ無限大制御

  若生 将史

  科学研究費助成事業／特別研究員奨励費, 2013年04月 - 2015年03月, 研究代表者

  競争的資金