• Transactions on Control, Automation and Systems Engineering
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• v.2 no.2
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• pp.116-120
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• 2000

This paper presents a method to assign robustly the closed loop system's poles in a specified disk by a state feedback for a linear time invariant system with structured or unstructured uncertainties. THe proposed robust design procedure includes two steps. Firstly, the perturbed closed loop matrix $A_{cl p}$ = $A_{cl}$ + Δ$A_{cl}$ is rearranged such that it is a function of the nominal closed loop matrix $A_{cl}$. Hence, we can control the positions of the perturbed closed loop poles by choosing $A_{cl}$ appropriately. Secondly, the feedback control law F that assigns the closed loop poles of the perturbed system in a specified disk is determined from the equation $A_{cl}$ = A + BF. A procedure for finding F is proposed based on partitioning every matrix of the equation $A_{cl}$ = A + BF in the horizontal direction.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2302-2304
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• 2000

This paper addresses a fuzzy controller for nonlinear systems control using a pole placement in a specified disk. In the method, we linearize a nonlinear plant about nominal operating points and represent it using TS fuzzy model and formulate the controller rules. A feedback control law for a local model is determined using a pole placement in a specified disk(${\alpha}$:center ${\gamma}$:radius} region so that the closed loop system is stable. A nonlinear system can be controlled by combining fuzzy controller with a pole placement scheme which can be used to modify the transient response such as damping ratio and overshoot. A stability of overall fuzzy control system is guaranteed in the Lyapunov sense. Finally, it is shown that the proposed method is feasible through a computer simulation.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.601-604
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• 1997

In this paper, a pole assignment problem in the unit disk for a linear discrete system is discussed. The analysis is based on the Luenberger's canonical form and Gershgorin's disk. The proposed method for pole assignment is convenient for a linear time invariant discrete system.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.176-179
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• 2000

This paper addresses a fuzzy controller for nonlinear systems control using a pole placement in a specified disk and fuzzy controller is redesign for Intelligent digital redesign method. for nonlinear system, we obtain continuous time state feedback gain that guarantee stability of globally TS fuzzy system. The feedback gain is satified pole placement in a specified disk region so that the closed loop system is stable, For digital control redesgin of continuous time TS fuzzy model, we does state matching and obtain feedback gain of digital controller. Finally, it is shown that the proposed method is feasible through a computer simulation.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.6
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• pp.707-712
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• 1998

본 논문에서는 선형 시불변 시스템에 대해 상태되먹임을 이용한 폐루프계의 지정된 영역내의 극배치법을 제안한다. 본 제안된 기법은 해밀톤 행렬의 하중행렬 Q의 설정에 의해 지정된 영역 (α중심, γ반경)내에 극배치가 가능함을 보인다. 먼저, Gershgorin의 이론을 적용하기 위해 해밀톤 행렬을 등가 변환시킨 후 행렬의 각 계수를 α와 γ의 관계를 이용하여 유도한다. 위의 관계를 만족하는 해밀톤 행렬의 각 하중행렬과 변환행렬을 이용하여 폐루프계의 상태되먹임 제어칙을 구한다. 또한 본 기법은 해밀톤 행렬과 최적제어와의 관계를 지니고 있으므로 얻어진 폐루프계는 최적제어법에서와 동일한 강인함을 가지게 된다. 끝으로 예제를 통하여 지정된 영역내의 극배치가 이루어짐을 보인다.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2287-2289
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• 2000

This paper focuses on the robust pole assignment for time varying uncertain linear systems in a specified disk. Based on Linear Matrix Inequality(LMI) approach, we give two sufficient conditions, one is for the analysis and another is for the design, that guarantee the robust pole assignment in a specified disk in the left half plane(L.H.P) while satisfying the robust stability. Since these conditions are expressed as LMI forms, we can easily check their feasibility using MATLAB control toolbox. Finally, we show by an example that our results are useful for analysis and design.

• Nonlinear Functional Analysis and Applications
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• v.28 no.1
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• pp.81-93
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• 2023

By utilizing a certain Libera integral operator considered on analytic multivalent functions in the unit disk U. Using the hypergeometric function and the Libera integral operator, we included a new convolution operator that expands on some previously specified operators in U, which broadens the scope of certain previously specified operators. We introduced and investigated the properties of new subclasses of functions f (z) ∈ A_p using this operator.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.440-445
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• 2000

Robust tracking controller of optical disk drive(ODD) is designed using quantitative feedback theory(QFT). Nominal plant model is identified from real system through modal test. Uncertainties and control performance of tracking servo are specified, and robust controller satisfying these specifications is designed in the QFT framework. To verify the performances of designed controller, experiment are performed in a digital signal processor(DSP) environment, and experimental results are compared with simulations.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.12
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• pp.1982-1989
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• 2004

In photoelasticity, the directions of principal stresses are given by isoclinic fringe patterns. In this study, photoelastic theory is represented by Jones calculus and the photoelastic 8-step phase shifting method is described. A feasibility study using computer simulation is done to get isoclinics from photoelastic fringes of a circular disk under diametral compression. Fringe patterns of the disk are generated from the stress-optic law. The magnitudes of isoclinics obtained from the fringe patterns of computer simulation and experiment are compared with those of theory. The results are close between them. Then, the 8-step phase shifting method is applied to get distributions of isoclinics along the specified lines of a cuved beam plate under tensile load. Experimental results obtained from the phase shifting method were compared with those of finite element analysis (ANSYS). It is confirmed that measurement of isoclinic distributions is possible by use of photoelasitc phase shifting method.

• ETRI Journal
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• v.39 no.6
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• pp.820-831
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• 2017

File systems and applications try to implement their own update protocols to guarantee data consistency, which is one of the most crucial aspects of computing systems. However, we found that the storage devices are substantially under-utilized when preserving data consistency because they generate massive storage write traffic with many disk cache flush operations and force-unit-access (FUA) commands. In this paper, we present DJFS (Delta-Journaling File System) that provides both a high level of performance and data consistency for different applications. We made three technical contributions to achieve our goal. First, to remove all storage accesses with disk cache flush operations and FUA commands, DJFS uses small-sized NVRAM for a file system journal. Second, to reduce the access latency and space requirements of NVRAM, DJFS attempts to journal compress the differences in the modified blocks. Finally, to relieve explicit checkpointing overhead, DJFS aggressively reflects the checkpoint transactions to file system area in the unit of the specified region. Our evaluation on TPC-C SQLite benchmark shows that, using our novel optimization schemes, DJFS outperforms Ext4 by up to 64.2 times with only 128 MB of NVRAM.