Research activity information

• Jul. 2024 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


• Jan. 2022 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


• Sep. 2021 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


• Apr. 2018 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

  WAKAIKI MASASHI

  Publisher


• Mar. 2018 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

  WAKAIKI MASASHI

  Japan society


• Apr. 2016 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

  WAKAIKI MASASHI

  International society


• Jan. 2015 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

  WAKAIKI MASASHI

  Japan society


• Mar. 2014 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

  WAKAIKI MASASHI

  Japan society


• Feb. 2014 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

  WAKAIKI MASASHI

  Japan society


• Nov. 2012 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

  WAKAIKI MASASHI

  Japan society

• Stabilization of infinite-dimensional systems under quantization and packet loss

  Masashi Wakaiki

  Institute of Electrical and Electronics Engineers (IEEE), Oct. 2025, IEEE Transactions on Automatic Control, 70(10) (10), 6625 - 6640, English

  [Refereed]

  Scientific journal


• Self-triggered stabilization of contracting systems under quantization

  Masashi Wakaiki

  Institute of Electrical and Electronics Engineers (IEEE), Aug. 2025, IEEE Transactions on Automatic Control, 70(8) (8), 5254 - 5269, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Characterizations of the Crandall–Pazy class of C0-semigroups on Hilbert spaces and their application to decay estimates

  Masashi Wakaiki

  Elsevier BV, Aug. 2025, Journal of Functional Analysis, 289(3) (3), 1 - 55, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Learning of Input Penalty Function for Zone Model Predictive Blood Glucose Control

  Yoshinobu IIMURA, Masashi WAKAIKI

  Last, The Society of Instrument and Control Engineers, Aug. 2024, Transactions of the Society of Instrument and Control Engineers, 60(8) (8), 464 - 475, Japanese

  [Refereed]

  Scientific journal


• 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, May 2024, Journal of Evolution Equations, 24(2) (2), 1 - 34, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

  Masashi Wakaiki

  Elsevier BV, Apr. 2024, Journal of Mathematical Analysis and Applications, 538(1) (1), 1 - 25, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Tube-based Model Predictive Control of Blood Glucose for Multiple Meal Scenarios

  Yoshinobu IIMURA, Masashi WAKAIKI

  Last, The Society of Instrument and Control Engineers, Dec. 2023, Transactions of the Society of Instrument and Control Engineers, 59(12) (12), 529 - 541, Japanese

  [Refereed]

  Scientific journal


• 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, Nov. 2023, Integral Equations and Operator Theory, 95(4) (4), 1 - 24, English

  [Refereed]

  Scientific journal


• 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), Oct. 2023, IET Control Theory & Applications, 18(4) (4), 511 - 529, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Construction of statistical models with High estimation accuracy for profit functions

  Yoshinobu Iimura, Masashi Wakaiki, Katsumi Homma, Yuhei Umeda, Hiroyuki Higuchi, Kazumi Kubota

  The Society of Instrument and Control Engineers, Jul. 2023, Transactions of the Society of Instrument and Control Engineers, 59(7) (7), 330 - 341, Japanese

  [Refereed]

  Scientific journal


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

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

  Elsevier BV, Jul. 2023, Automatica, 153, 1 - 9, English, Co-authored internationally

  [Refereed]

  Scientific journal


• 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, Jun. 2023, ESAIM: Control, Optimisation and Calculus of Variations, 29, 1 - 42, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• 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), May 2023, IEEE Control Systems Letters, 7, 1772 - 1777, English, Co-authored internationally

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki

  Institute of Electrical and Electronics Engineers (IEEE), Mar. 2023, IEEE Transactions on Automatic Control, 68(3) (3), 1776 - 1783, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

  Hideki Sano, Masashi Wakaiki, Takaharu Yaguchi

  Research Institute of Signal Processing, Japan, Nov. 2022, Journal of Signal Processing, 26(6) (6), 147 - 158, English

  [Refereed]

  Scientific journal


• 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), Jul. 2022, IEEE Transactions on Control Systems Technology, 30(4) (4), 1696 - 1710, English

  [Refereed]

  Scientific journal


• 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, Jun. 2022, Mathematics of Control, Signals, and Systems, 34(4) (4), 789 - 817, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

  Hideki Sano, Masashi Wakaiki

  Informa UK Limited, Jun. 2022, SICE Journal of Control, Measurement, and System Integration, 15(2) (2), 182 - 190, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

  Masashi Wakaiki

  May 2022, Proceedings of 13th Asian Control Conference, 1244 - 1245, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki

  Elsevier BV, Apr. 2022, Systems & Control Letters, 162, 1 - 8, English

  [Refereed]

  Scientific journal


• 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), Mar. 2022, Mathematical Control and Related Fields, 12(1) (1), 245 - 273, English

  [Refereed]

  Scientific journal


• 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, Dec. 2021, Journal of Evolution Equations, 21(4) (4), 4575 - 4597, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Strong stability of sampled-data Riesz-spectral systems

  Masashi Wakaiki

  Society for Industrial & Applied Mathematics (SIAM), Oct. 2021, SIAM Journal on Control and Optimization, 59(5) (5), 3498 - 3523, English

  [Refereed]

  Scientific journal


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

  Hideki Sano, Masashi Wakaiki

  Institute of Electrical and Electronics Engineers (IEEE), Oct. 2021, IEEE Transactions on Automatic Control, 66(10) (10), 4982 - 4989, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• 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, Jul. 2021, Entropy, 23(7) (7), 904 - 904, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

  Takeru Terauchi, Katsuya Suto, Masashi Wakaiki

  Apr. 2021, Proceedings of the 93rd IEEE Vehicular Technology Conference, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Ahmet Cetinkaya, Hideaki Ishii

  Aug. 2020, IEEE Transactions on Automatic Control, 65(8) (8), 3560 - 3575, English

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki, Yutaka Yamamoto

  Lead, Apr. 2020, Systems & Control Letters, 138, 1 - 8, English

  [Refereed]

  Scientific journal


• Event-triggered control of infinite-dimensional systems

  Masashi Wakaiki, Hideki Sano

  Feb. 2020, SIAM Journal on Control and Optimization, 58(2) (2), 605 - 635, English

  [Refereed]

  Scientific journal


• An LMI approach to stability analysis of coupled parabolic systems

  Masashi Wakaiki

  Jan. 2020, IEEE Transactions on Automatic Control, 65(1) (1), 404 - 411, English

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki, Hideki Sano

  Jan. 2020, Mathematics of Control, Signals, and Systems, 32(1) (1), 1 - 58, English

  [Refereed]

  Scientific journal


• Supervisory control of discrete-event systems under attacks

  Masashi Wakaiki, Paulo Tabuada, Joao P. Hespanha

  Dec. 2019, Dynamic Games and Applications, 9(4) (4), 965 - 983, English

  [Refereed]

  Scientific journal


• 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), Dec. 2019, IET Electric Power Applications, 13(12) (12), 2044 - 2051, English

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki, Katsuya Suto, Izumi Masubuchi

  Institute of Electrical and Electronics Engineers Inc., Sep. 2019, IEEE Vehicular Technology Conference, 2019-, English

  International conference proceedings


• 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

  Sep. 2019, 計測自動制御学会論文集, 55(9) (9), 582 - 584, Japanese

  [Refereed]

  Scientific journal


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

  Hideki Sano, Masashi Wakaiki

  Jul. 2019, Japan Journal of Industrial and Applied Mathematics, 36(2) (2), 325 - 355, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

  Masashi Wakaiki, Tadanao Zanma, Kang-Zhi Liu

  Jul. 2019, IEEE Transactions on Automatic Control, 64(7) (7), 2929 - 2936, English

  [Refereed]

  Scientific journal


• 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), Jun. 2019, IEEE Transactions on Green Communications and Networking, 3(2) (2), 329 - 342, English

  [Refereed]

  Scientific journal


• Backstepping observers for two linearized Kermack-McKendrick models

  Hideki Sano, Masashi Wakaiki, Hayate Maruyama

  Oct. 2018, Proceedings of the 17th IFAC Workshop on Control Applications of Optimization, 456 - 461, English

  [Refereed]

  International conference proceedings


• Stabilization of networked control systems under clock offsets and quantization

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

  Institute of Electrical and Electronics Engineers Inc., Jun. 2018, IEEE Transactions on Automatic Control, 63(6) (6), 1618 - 1633, English

  [Refereed]

  Scientific journal


• 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

  Jun. 2018, Proceedings of the 2018 American Control Conference, English

  [Refereed]

  International conference proceedings


• Quantized output feedback stabilization under DoS attacks

  Masashi Wakaiki, Ahmet Cetinkaya, Hideaki Ishii

  Jun. 2018, Proceedings of the 2018 American Control Conference, English

  [Refereed]

  International conference proceedings


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

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

  May 2018, Proceedings of the IEEE International Conference on Communications 2018, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki

  Jan. 2018, IEEE Control Systems Letters, 2(1) (1), 157 - 162, English

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki, Masaki Ogura, João P. Hespanha

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

  [Refereed]

  Scientific journal


• Stabilization of switched systems with sampled and quantized output feedback

  Masashi Wakaiki, Yutaka Yamamoto

  Dec. 2017, IET Control Theory and Applications, 11(12) (12), 1913 - 1921, English

  [Refereed]

  Scientific journal


• 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

  Aug. 2017, 電気学会論文誌Ｂ（電力・エネルギー部門誌）, 137(8) (8), 596 - 597, Japanese

  [Refereed]

  Scientific journal


• Stabilization of systems with asynchronous sensors and controllers

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  Jul. 2017, Automatica, 81(7) (7), 314 - 321, English

  [Refereed]

  Scientific journal


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

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

  Jul. 2017, Proceedings of the 36th Chinese Control Conference, English

  [Refereed]

  International conference proceedings


• Quantized Output Feedback Stabilization by Luenberger Observer

  Masashi Wakaiki, Tadanao Zanma, Kang-Zhi Liu

  Jul. 2017, Proceedings of the 20th IFAC World Congress, English

  [Refereed]

  International conference proceedings


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

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

  Jul. 2017, Proceedings of the 36th Chinese Control Conference, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Yutaka Yamamoto

  Jun. 2017, IEEE Transactions on Automatic Control, 62(6) (6), 2958 - 2964, English

  [Refereed]

  Scientific journal


• Delayed bet-hedging resilience strategies under environmental fluctuations

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

  May 2017, PHYSICAL REVIEW E, 95(5) (5), 1 - 8, English

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


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

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

  Feb. 2017, Proceedings of the 5th International Conference on System Modeling and Optimization, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Masaki Ogura, João Pedro Hespanha

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

  [Refereed]

  International conference proceedings


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

  Masaki Ogura, Masashi Wakaiki, Victor M. Preciado

  Dec. 2016, 2016 IEEE 55th Conference on Decision and Control, CDC 2016, 4178 - 4183, English

  [Refereed]

  International conference proceedings


• Stability analysis of sampled-data switched systems with quantization

  Masashi Wakaiki, Yutaka Yamamoto

  Jul. 2016, AUTOMATICA, 69(7) (7), 157 - 168, English

  [Refereed]

  Scientific journal


• 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

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

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  2016, 2016 AMERICAN CONTROL CONFERENCE (ACC), 4239 - 4244, English

  [Refereed]

  International conference proceedings


• 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

  2016, 2016 AMERICAN CONTROL CONFERENCE (ACC), 709 - 714, English

  [Refereed]

  International conference proceedings


• 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

  2016, 2016 19TH INTERNATIONAL CONFERENCE ON ELECTRICAL MACHINES AND SYSTEMS (ICEMS 2016), English

  [Refereed]

  International conference proceedings


• Robust Stability under Asynchronous Sensing and Control

  Masashi Wakaiki, Masaki Ogura, Joao P. Hespanha

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

  [Refereed]

  International conference proceedings


• 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

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

  [Refereed]

  International conference proceedings


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

  Kunihisa Okano, Masashi Wakaiki, Joao P. Hespanha

  Apr. 2015, Proceedings of the 18th International Conference on Hybrid Systems: Computation and Control, English

  [Refereed]

  International conference proceedings


• Stabilization of Networked Control Systems with Clock Offsets

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

  2015, 2015 AMERICAN CONTROL CONFERENCE (ACC), 3522 - 3527, English

  [Refereed]

  International conference proceedings


• Observability of linear systems under adversarial attacks

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

  2015, 2015 AMERICAN CONTROL CONFERENCE (ACC), 2439 - 2444, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Yutaka Yamamoto

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

  [Refereed]

  International conference proceedings


• Control under Clock Offsets and Actuator Saturation

  Masashi Wakaiki, Kunihisa Okano, Joao P. Hespanha

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

  [Refereed]

  International conference proceedings


• Output Feedback Stabilization of Switched Linear Systems with Limited Information

  Masashi Wakaiki, Yutaka Yamamoto

  Dec. 2014, Proceedings of the 53rd IEEE Conference on Decision and Control, 3892 - 3897, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Yutaka Yamamoto

  Oct. 2014, Systems & Control Letters, 72(10) (10), 80 - 85, English

  [Refereed]

  Scientific journal


• Quantized feedback stabilization of sampled-data switched linear systems

  Masashi Wakaiki, Yutaka Yamamoto

  Lead, Aug. 2014, Proceedings of the 19th IFAC World Congress, 9979 - 9984, English

  [Refereed]

  International conference proceedings


• Quantized output feedback stabilization of switched linear systems

  Masashi Wakaiki, Yutaka Yamamoto

  Jul. 2014, Proceedings of the 21st International Symposium on Mathematical Theory of Networks and Systems, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Ozbay

  Apr. 2014, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 59(4) (4), 1099 - 1105, English

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Özbay

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

  [Refereed]

  Scientific journal


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

  Masashi Wakaiki, Yutaka Yamamoto

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

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Oezbay

  Aug. 2012, IEEE TRANSACTIONS ON AUTOMATIC CONTROL, 57(8) (8), 2089 - 2094, English

  [Refereed]

  Scientific journal


• Robust stabilization for distributed parameter systems by stable controllers

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Ozbay

  Jul. 2012, Proceedings of the 20th International Symposium on Mathematical Theory of Networks and Systems, English

  [Refereed]

  International conference proceedings


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

  Masashi Wakaiki, Yutaka Yamamoto, Hitay Ozbay

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

  [Refereed]

  International conference proceedings

• 「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

  Jun. 2024, システム/制御/情報, 68(6) (6), 205 - 205, Japanese

  Introduction other


• 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

  Lead, May 2024, 数理科学, 62(6) (6), 66 - 66, Japanese

  Book review


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

  若生 将史

  Mar. 2023, システム／制御／情報, 67(3) (3), 127 - 127, Japanese

  Meeting report


• 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

  Aug. 2021, システム/制御/情報, 65(8) (8), 305 - 310, Japanese

  [Refereed]

  Introduction scientific journal


• 強連続半群と制御理論

  若生将史, 佐野英樹

  Jun. 2021, 計測と制御, 60(6) (6), 369 - 374, Japanese

  [Refereed]

  Introduction scientific journal


• イベントトリガ制御の基礎

  若生 将史

  Nov. 2019, システム/制御/情報, 63(11) (11), 455 - 460, Japanese

  [Refereed]

  Introduction scientific journal


• 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

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

  The Society of Instrument and Control Engineers, Jul. 2017, 計測と制御, 56(7) (7), 486 - 491, Japanese

  [Refereed]

  Introduction scientific journal


• 同期誤差を考慮したネットワーク化制御

  Masashi Wakaiki, Kunihisa Okano

  The Society of Instrument and Control Engineers, Nov. 2016, 計測と制御, 55(11) (11), 984 - 989, Japanese

  [Refereed]

  Introduction scientific journal


• 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

  Masashi Wakaiki

  The Society of Instrument and Control Engineers, Nov. 2014, 計測と制御, 53(11) (11), 1048 - 1048, Japanese

  [Refereed]

  Introduction scientific journal

• 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

  Joint work, コロナ社, Aug. 2019

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

  Masashi Wakaiki

  Online Seminar on Input-to-State Stability and its Applications, Aug. 2023, English

  [Invited]

  Invited oral presentation


• 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, Jul. 2023, English

  [Invited]

  Invited oral presentation


• 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, Dec. 2022, Japanese

  Oral presentation


• 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, Sep. 2022, English

  Oral presentation


• 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, Aug. 2022, English

  Oral presentation


• 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」, Mar. 2022, Japanese

  Nominated symposium


• 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, Mar. 2022, Japanese

  Oral presentation


• 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, Mar. 2021, Japanese

  Oral presentation


• 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」, Nov. 2020

  Nominated symposium


• 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, Nov. 2020

  Oral presentation


• 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, Sep. 2020, Japanese

  Oral presentation


• 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, May 2020

  Oral presentation


• 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, May 2020

  Oral presentation


• 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, Dec. 2019, Japanese

  Oral presentation


• 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, Dec. 2019, Japanese

  Oral presentation


• 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

  Hayate Maruyama, Hideki Sano, Masashi Wakaiki

  第6回計測自動制御学会制御部門マルチシンポジウム, Mar. 2019, Japanese, Domestic conference

  Poster presentation


• 無限次元システムのサンプル値サーボ問題について

  WAKAIKI Masashi, SANO HIDEKI

  2018年度 応用数学合同研究集会, Dec. 2018, Japanese, Domestic conference

  Oral presentation


• 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

  Hideki Sano, Masashi Wakaiki

  2018年度 応用数学合同研究集会, Dec. 2018, Japanese, 大津, Domestic conference

  Oral presentation


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

  Katsuya Suto, Masashi Wakaiki

  IEICE Smartcom 2018, Oct. 2018, English, International conference

  Poster presentation


• 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

  Hayate Maruyama, Hideki Sano, Masashi Wakaiki

  日本応用数理学会2018年 年会, Sep. 2018, Japanese, 名古屋, Domestic conference

  Oral presentation


• Event-triggered control systems

  Masashi Wakaiki

  SICE Annual Conference 2018 Workshop ''New Trends in Networked Control', Sep. 2018, English, International conference

  Nominated symposium


• DoS攻撃の下での量子化制御

  Masashi Wakaiki, Ahmet Cetinkaya, Hideaki Ishii

  第61回システム制御情報学会研究発表講演会, May 2018, Japanese, Domestic conference

  Oral presentation

• IEEE


• THE INSTITUTE OF SYSTEMS, CONTROL AND INFORMATION ENGINEERS


• THE JAPAN SOCIETY FOR INDUSTRIAL AND APPLIED MATHEMATICS


• THE MATHEMATICAL SOCIETY OF JAPAN


• THE SOCIETY OF INSTRUMENT AND CONTROL ENGINEERS

• Development of the theory of analysis and design for infinite-dimensional digital control systems

  若生 将史

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Kobe University, Apr. 2024 - Mar. 2029, Principal investigator


• Robust stability analysis of infinite-dimensional sampled-data systems

  若生 将史

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Early-Career Scientists, Grant-in-Aid for Early-Career Scientists, Kobe University, 01 Apr. 2020 - 31 Mar. 2024

  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), Apr. 2017 - Mar. 2020, Principal investigator

  Competitive research funding


• 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, Apr. 2013 - Mar. 2015, Principal investigator

  Competitive research funding