• International Journal of Control, Automation, and Systems
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• v.5 no.1
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• pp.93-98
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• 2007

A class of new observers in descriptor linear systems, proportional-derivative(PD) observers, are proposed. A parametric design approach for such observers is proposed based on a complete parametric solution to the generalized Sylvester matrix equation. The approach provides complete parameterizations for all the observer gains, gives the parametric expression for the corresponding left eigenvector matrix of the observer system matrix, realizes elimination of impulsive behaviors, and guarantees the regularity of the observer system.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.492-495
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• 1995

A simple method to design observers for linear describtor systems with unmeasureable disturbance is represented by the response of a linear free system. The sufficient conditions for the existence of the observer are given. The design procedures of an identify and a minimal order observers are shown, respectively.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.287-290
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• 1996

Fault diagnosis problem is currently the subject of extensive research and numerous survey paper can be found. Although several works are studied on the fault detection and isolation observers and the residual generators, those are concerned with only the detection of actuator failures or sensor failures. So, the perfect detection and isolation is strongly required for practical applications. In this paper, a, strategy of fault diagnosis using multiple proportional integral (PI) observers including the magnitude of actuator failures is provided. It is shown that actuator failures are detected and isolated perfectly by monitoring the integrated error between actual output and estimated output by a PI observer. Also in presence of complex actuator and sensor failures, these failures are detected and isolated by multiple PI observers.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1997.11a
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• pp.19-25
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• 1997

At Eurocrypt'91, D. Chaum and E. Heyst introduced the notion of group signatures, which allow members of a group to make signatures on behalf of the group while remaining anonymous. This paper first presents a new type of group signatures with observers. In group signatures with observers, our solution is the most practical group signature scheme, under the assumption that Chaum's electronic wallet is secure.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.6
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• pp.487-493
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• 2001

In this paper, a new reduced-order dynamic observer method is presented. Two types of observers are pronounced, namely, the model based reduced-order dynamic observer and the Luenburger type reduced-order dynamic observer. Useful design algorithms are also provided for each structure. The essential features of the proposed observed design methods are addressed to be qualified ad effective observers. The proposed method clarifies the duality between the controller and observer designs.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.241-244
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• 2002

Using disturbance observers is effective in enhancing the performance of systems in presence of disturbances. In this paper, we present a novel design of disturbance observers to achieve enhanced robust performance. In addition, we propose a new method of reducing the effect of measurement noise via modification of plant modeling in disturbance observer.

• Journal of the Korean Data and Information Science Society
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• v.15 no.1
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• pp.263-271
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• 2004

This article presents a new measure of chance-corrected interobserver agreement among multivariate ratings of many observers. Modifying an approach by Berry and Mielke, a new agreement measure is proposed. The important modificaton is to use the volume of simplex composed of data points as the disagreement masure. The proposed measure accounts agreement for multivariate interval observations among many observers. Hypothetical and real-life data sets are analyzed for illustrative purpose.

• ETRI Journal
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• v.25 no.3
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• pp.156-170
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• 2003

Gamut compression algorithms have traditionally been defined functionally and then tested with deductive methods, e.g., psychophysical experiments. Our study offers an alternative, an inductive method, in which observers judge image colors to represent the original images more accurately. We developed a computer-controlled interactive tool that modifies the color appearance of pictorial images displayed on a monitor. In experiments, observers used the tool to alter color pixels according to the region of color space to which they belonged. We created three different gamut compression algorithms based on the observer experimental data. Observer groups evaluated the performance of the newly-developed algorithms, existing gamut compression algorithms, and an image based on the average observers' results from experiments in this study. The study of gamut extension is unlike the study of gamut compression in that it mainly deals with the degree of image pleasantness as judged by observers. The results of the gamut extension experiments in this study not only make available worthwhile data but also suggest a methodology for using the observer experimental tool for future gamut extension research.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.232-235
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• 2008

This paper presents an LMI-based method to design reduced order observers by which we can substitute full order sliding mode observers for a class of uncertain time-delay systems. We show that a reduced order observer can be constructed as long as the uncertain system satisfies the previous LMI existence conditions of a full order sliding mode observer. And we give explicit formulas of the reduced order observer gain matrices. Finally, we give a simple LMI-based design algorithm, together with a numerical design example.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.2
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• pp.41-47
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• 1997

Fault diagnosis problem is currently a subject of extensive research in the control field. Although there are several works on the fault detection and isolation observers and the residual generators, those are con- cerned with only the detection of actuator failures or sensor failures. So, the perfect detection and isolation for the actuator and sensor failures is strongly required in the field of the practical applications. In this paper, a strategy of fault diagnosis using multiple proportional integral (PI) observers including the magnitude of actuator failures is provided. It is shown that actuator failures are detected and isolated perfectly by monitoring the integrated error between actual output and estimated output by a PI observer. Also in presence of complex actuator and sensor failures, these failures are detected and isolated by multiple PI observers.