[Partial/Selected] List of Journal Publications by T. Hagiwara

Hankel Norm Analysis of Sampled-Data Systems

• The L_∞/L₂ Hankel Operator/Norm of Sampled-Data Systems (as listed below)
• On Well-Definability of the L_∞/L₂ Hankel Operator and Detection of All the Critical Instants in Sampled-Data Systems (as listed below)
• External Positivity of Sampled-Data Systems and Their L_q/L_∞ Hankel Norm Analysis
• Quasi L₂/L₂ Hankel Norms and L₂/L₂ Hankel Norm/Operator of Sampled-Data Systems
• L₂/L₁ Induced Norm and Hankel Norm Analysis in Sampled-Data Systems

Generalized H₂ (L_∞/L₂-Induced Norm, L_∞/L₂-Hankel Norm) Analysis and Synthesis of Sampled-Data Systems

• Extensive Theoretical/Numerical Comparative Studies on H₂ and Generalised H₂ Norms in Sampled-Data Systems
• Upper/Lower Bounds of Generalized H₂ Norms in Sampled-Data Systems with Convergence Rate Analysis and Discretization Viewpoint
• The L_∞/L₂ Hankel Operator/Norm of Sampled-Data Systems
• On Well-Definability of the L_∞/L₂ Hankel Operator and Detection of All the Critical Instants in Sampled-Data Systems
• The Generalized H₂ Controller Synthesis Problem of Sampled-Data Systems

L_∞ Induced-Norm Analysis of Continuous-Time and Sampled-Data Systems; with Sampled-Data Controller Synthesis

• Quasi-Finite-Rank Approximation of Compression Operators on L_∞[0,h) with Application to Stability Analysis of Time-Delay Systems (as listed below)
• Computing the L_∞[0,h)-Induced Norm of a Compression Operator via Fast-lifting
• L_∞-Induced Norm Analysis of Sampled-Data Systems via Piecewise Constant and Linear Approximations
• Computing the L_∞-Induced Norm of LTI Systems via Kernel Approximation and Its Comparison with Input Approximation
• L₁ Discretization for Sampled-Data Controller Synthesis via Piecewise Linear Approximation
• Further Results on the L₁ Analysis of Sampled-Data Systems via Kernel Approximation Approach
• Computing the L_∞-Induced Norm of LTI Systems: Generalization of Piecewise Quadratic and Cubic Approximations
• L₁ Optimal Controller Synthesis for Sampled-Data Systems via Piecewise Linear Kernel Approximation
• Generalized Framework for Computing the L_∞-Induced Norm of Sampled-Data Systems

Time-Delay Systems

• Two-Degree-of-Freedom LQI Servo Systems; State-Predictive Control for Systems with Pure Delay (as listed below)
• Quasi-Finite-Rank Approximation of Compression Operators in Sampled-Data Systems and Time-Delay Systems (as listed below)
• Fast-Lifting Approach to the Computation of the Spectrum of Retarded Time-Delay Systems
• Concatenated Solutions of Delay-Differential Equations and Their Representation with Time-Delay Feedback Systems
• Conversion of Linear Time-Invariant Delay-Differential Equations with External Input and Output into Representation as Time-Delay Feedback Systems
• Numerical Methods for Spectrum Computation of Monodromy Operators via Non-Causal Hold Discretization
• Conversion of Linear Time-Invariant Time-Delay Feedback Systems into Delay-Differential Equations with Commensurate Delays
• Quasi-Finite-Rank Approximation of Compression Operators on L_∞[0,h) with Application to Stability Analysis of Time-Delay Systems (as opposed to a relevant study on L₂[0,h))
• Spectrum of Monodromy Operator for a Time-Delay System with Application to Stability Analysis
• Modified State Predictive Control Aimi ng at Improving Robust Stability

Robust Stability Analysis of Discrete-Time Systems

• Note on Well-Posedness and Separator-Type Robust Stability Theorem of LTI Systems
• Unified Treatment of Robust Stability Conditions for Discrete-Time Systems through an Infinite Matrix Framework
• Robust Stability Analysis Based on FIR Scaling for Discrete-Time Linear Time-Invariant Systems

Discrete-Time Causal/Noncausal Linear Periodically Time-Varying (LPTV) Scaling

• Noncausal Linear Periodically Time-Varying Scaling for Robust Stability Analysis of Discrete-Time Systems: Frequency-Dependent Scaling Induced by Static Separators
• Robust Stabilizing Controller Synthesis Based on Discrete-Time Noncausal Linear Periodically Time-Varying Scaling (in Japanese)
• Properties of Discrete-Time Noncausal Linear Periodically Time-Varying Scaling and Their Relationship with Shift-Invariance in Lifting-Timing
• Robust Performance Controller Synthesis Based on Discrete-Time Noncausal Linear Periodically Time-Varying Scaling
• Demonstrating the Effectiveness of Robust Performance Synthesis Based on Noncausal Linear Periodically Time-Varying Scaling through Control Experiments of Cart Inverted Pendulum (in Japanese)
• Robust Stability Analysis with Cycling-Based LPTV Scaling: Part I. Fundamental Results on Its Relationship with Lifting-Based LPTV Scaling
• Robust Stability Analysis with Cycling-Based LPTV Scaling: Part II. Its Properties under the Use of FIR Separators

Fast-Lifting, Modified Fast-Sample/Fast-Hold Approximation, and Continuous-Time Causal/Noncausal Linear Periodically Time-Varying (LPTV) Scaling

• Linear Periodically Time-Varying Scaling and Its Properties
• Modified Fast-Sample/Fast-Hold Approximation for Sampled-Data System Analysis
• Separator-Type Robust Stability Theorem of Sampled-Data Systems Allowing Noncausal LPTV Scaling
• Modified Fast-Sample/Fast-Hold Approximation and γ-Independent H_∞-Discretization for General Sampled-Data Systems by Fast-Lifting
• Stability Analysis of Sampled-Data Systems with Static Sector Nonlinearities via Causal Linear Periodically Time-Varying Scaling
• Quasi-Finite-Rank Approximation of Compression Operators in Sampled-Data Systems and Time-Delay Systems (on L₂[0,h) as opposed to L_∞[0,h))
• Block Checker/Diagonal Transformation Matrices, Their Properties, and the Interplay with Fast-Lifting
• Fast-Lifting Approach to the Computation of the Spectrum of Retarded Time-Delay Systems (as listed above)

Frequency-Domain Theory of Sampled-Data Systems

• Computation of the Frequency Response Gains and $ H_\infty $-Norm of a Sampled-Data System
• FR-Operator Approach to the $ H_2 $ Analysis and Synthesis of Sampled-Data Systems
• Frequency Response of Sampled-Data Systems
• Absolute Stability of Sampled-Data Systems with a Sector Nonlinearity
• Popov-Type Criterion for Stability of Nonlinear Sampled-Data Systems
• Robust Stability of Sampled-Data Systems under Possibly Unstable Additive/Multiplicative Perturbations
• Generalization of Stability Criteria for Nonlinear Sampled-Data Systems (in Japanese)
• Bisection Algorithm for Computing the Frequency Response Gain of Sampled-Data Systems---Infinite-Dimensional Congruent Transformation Approach
  [PDF file purchased from IEEE Reprints; for corrigenda to printer's errors after the proofreading process, see IEEE Trans. Automat. Contr., Vol. 47, No. 1, p. 201, 2002.]
• Upper and Lower Bounds of the Frequency Response Gain of Sampled-Data Systems
• Nyquist Stability Criterion and Positive-Realness of Sampled-Data Systems
• Spectral Analysis and Singular Value Computations of the Noncompact Frequency Response and Compression Operators in Sampled-Data Systems
  [PDF file; accessible only from within our university to conform to the copyright assignment agreement with SIAM]
  [corrigenda]
• Positive-Realness Analysis of Sampled-Data Systems and Its Applications
  [corrigenda]
• A Study on the Spectrum of the Sampled-Data Transfer Operator with Applications to Robust Exponential Stability Problems
  [PDF file; accessible only from within our university to conform to the copyright assignment agreement with SIAM]
• On Sensitivity Reduction Problems of Sampled-Data Systems: Relationships to the Problems of Discrete-Time Systems

Sampled-Data Systems & Linear System Theory

• Preservation of Reachability and Observability under Sampling with a First-Order Hold
• Analytic Study on the Intrinsic Zeros of Sampled-Data Systems
• Note on Reachability Indices of Augmented Systems
• Simultaneous Pole Assignment by Multi-Structured Multirate Sampled-Data Controllers
• Improved Results for Simultaneous Pole Assignment by Multirate Sampled-Data Controllers
• Sequential Tuning Methods of LQ/LQI Controllers for Multivariable Systems and Their Application to Hot Strip Mills
• Time-Sharing Multirate Sample-Hold Controllers and Their Application to Reliable Stabilization
• Robust Performance Analysis of Sampled-Data Systems against Parameter Uncertainties
• Wronskian Approach to Observability and the Unobservable Subspace through the Null-Space Analysis (in Japanese)
• Internal/External Positivity of Sampled-Data Systems: Definitions and the Necessary and Sufficient Conditions

Periodic System Analysis

• Frequency Response Gain Computation of Finite-Dimensional Linear Continuous-Time Systems
• Stability Analysis and Harmonic Lyapunov Equations of Continuous-Time Periodic Systems
• Existence Conditions and Properties of the Frequency Response Operators of Continuous-Time Periodic Systems
  [PDF file; accessible only from within our university to conform to the copyright assignment agreement with SIAM]
• Norm Computations by the Skew Analysis of the Frequency Response Operators of Continuous-Time Periodic Systems
• Truncating the Harmonic Lyapunov Equation for the $ H2 $-Norm Computation of Linear Continuous-Time Periodic Systems
• 2-Regularized Nyquist Criterion in Linear Continuous-Time Periodic Systems and Its Implementation
  [PDF file; accessible only from within our university to conform to the copyright assignment agreement with SIAM]
• Some Remarks on Realization of Periodic Systems
• Linear Periodically Time-Varying Scaling and Its Properties(as listed above)
• Noncausal Linear Periodically Time-Varying Scaling for Robust Stability Analysis of Discrete-Time Systems: Frequency-Dependent Scaling Induced by Static Separators(as listed above)

Two-Degree-of-Freedom LQI Servo Systems & Their Applications

• Two-Degree-of-Freedom LQI Servo Systems; State Feedback Case
• Two-Degree-of-Freedom LQI Servo Systems; Analysis of the Performance Deterioration by the Introduction of an Observer
• Two-Degree-of-Freedom LQI Servo Systems; Use of Frequency-Dependent Weighting Matrices for Sensitivity Reduction
• Two-Degree-of-Freedom LQI Servo Systems; Optimal Observer for Disturbance Rejection
• Two-Degree-of-Freedom LQI Servo Systems; Application to the Positioning Control of a Pneumatic Servo Cylinder (in Japanese)
• Two-Degree-of-Freedom LQI Servo Systems; State-Predictive Control for Systems with Pure Delay
• Trajectory Tracking Control of a Two-Axis Arm Driven by Pneumatic Artificial Muscles (in Japanese)

Stability Analysis of Nonlinear and Time-Varying Feedback Systems

• Absolute Stability of Sampled-Data Systems with a Sector Nonlinearity (as listed above)
• Popov-Type Criterion for Stability of Nonlinear Sampled-Data Systems (as listed above)
• Stability Condition of a Class of Nonlinear Feedback Systems: Reduction to a Convex Problem
• Generalization of Stability Criteria for Nonlinear Sampled-Data Systems (as listed above)
• LMI Representation of a Stability Condition for a Class of Nonlinear Feedback Systems
• A Study on Stability of Optimal Regulators under Online Gain Adjustment
• Stability Analysis of Sampled-Data Systems with Static Sector Nonlinearities via Causal Linear Periodically Time-Varying Scaling (as listed above)
• Causality of General Input-Output Systems and Extended Small-Gain Theorem for Their Feedback Connection

Control Applications

• Two-Degree-of-Freedom LQI Servo Systems; Application to the Positioning Control of a Pneumatic Servo Cylinder (as listed above)
• Trajectory Tracking Control of a Two-Axis Arm Driven by Pneumatic Artificial Muscles (as listed above)
• Demonstrating the Effectiveness of Robust Performance Synthesis Based on Noncausal Linear Periodically Time-Varying Scaling through Control Experiments of Cart Inverted Pendulum (as listed above)
• Nonlinear Control with Integral Compensation for Output Voltage of Boost Converters Based on Discretized Bilinear Model I---Modeling and Identification (in Japanese)
• Nonlinear Control with Integral Compensation for Output Voltage of Boost Converters Based on Discretized Bilinear Model II---Derivation of a Control Law and Verification by Experiments (in Japanese)
• Nonlinear Output Feedback Control for Average Output Voltage of Boost Converters Based on Their Discretized Bilinear Model (in Japanese)
• Atmosphere Dynamics Modeling and Hydrogen Ratio Control of Horizontal Continuous Annealing Furnace (in Japanese)
• Nonlinear Control via the SOS Method for the Output Voltage of Buck Converters Based on Discretized Bilinear Models (in Japanese)

Miscellaneous Articles

• Expository article on the Frequency-Domain Study of Sampled-Data Systems (in Japanese)
• Book review (IEEE Trans. Automat. Contr., Aug. 1997.) for "Optimal Sampled-Data Control Systems by Tongwen Chen and Bruce Francis"
• Expository article on the Recent Developments of Sampled-Data Control Theory (in Japanese)
• Expository article on Bisection Algorithms for the Frequency Response Gain Computation of Sampled-data Systems (in Japanese)
• Expository article on the Recent Studies on Input-Output Stability of Nonlinear Continuous/Sampled-Data Systems (in Japanese)
• Expository article; Brief Introduction to Digital and Sampled-Data Control Systems for Novices (in Japanese)
• Expository article; New Advances in Sampled-Data Control and Digital Control---with Primary Focus on Fast-Lifting and Noncausal Linear Periodically Time-Varying Scaling--- (in Japanese)
• Expository article; Representation Models of Time-Delay Systems and Their Initial Value Problems (in Japanese)
• Expository article; Robust Stability Analysis Based on Dynamic Scaling for Discrete-Time Systems (in Japanese)