• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1-6
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• 2003

This paper considers the problem of determining a set of stabilizing first order controller gains, for a given linear time invariant plant, that meets or exceeds closed loop step response specifications. The method utilizes two recent results: For a given system, (1) finding a set of stabilizing first order controller gains and (2) the relationship between time response (overshoot and speed) and the coefficients of the characteristic polynomial. The method allows us to extract a subset of first order controller gains that meets stability as well as time domain performance requirements. The computations involved are the intersections of two dimensional sets described by linear and quadratic inequalities in the controller design space. It is illustrated by examples.

• Journal of Korean Library and Information Science Society
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• v.19
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• pp.59-81
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• 1992

This study investigates Japanese-made Chinese Characters in JIS X 0212-1990(Code of the Su n.0, pplementary Japanese Graphic Character Set for Information Interchange). As a results of detailed investigation, it is found that the number of Japanese-made Chinese Characters in su n.0, pplementary set reaches to 69 characters. Among them, 29 characters are not listed even in the best known chinese character dictionary [대한화사전]. 30 characters are found in the chinese character dictionaries published in Korea, while 39 characters are not found in any of those dictionaries. The distinctive characteristic of Japanese-made Chinese characters is that those chinese characters are made in order to name the things, such as fishes, birds, trees, which do not have Chinese-made Chinese Characters.

• Bulletin of the Korean Mathematical Society
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• v.39 no.2
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• pp.185-198
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• 2002

We Consider the fuzzification of sub-implicative ideals in BCI-algebras, and investigate some related properties. We give conditions for a fuzzy ideal to be a fuzzy sub-implicative ideal. we show that (1) every fuzzy sub-implicative ideal is a fuzzy ideal, but the converse is not true, (2) every fuzzy sub-implicative ideal is a fuzzy positive implicative ideal, but the converse is not true, and (3) every fuzzy p-ideal is a fuzzy sub-implicative ideal, but the converse is not true. Using a family of sub-implicative ideals of a BCI-algebra, we establish a fuzzy sub-implicative ideal, and using a level set of a fuzzy set in a BCI-algebra, we give a characterization of a fuzzy sub-implicative ideal.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.5
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• pp.892-897
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• 2007

This paper presents the output filter design and the output characteristic analysis by cut-off frequency set up of the LCR filter on NPC multi-level inverter with trap-filter. The single-phase NPC three-level inverter operates at low switching frequency. The proposed LC trap filter is comprised of a conventional LCR output filter, by using LC trap filter the need for high damping resistor and low LC cut-off frequency is eliminated. Also. low damping resistor is increased the output filter system. The multilevel inverter system used NPC type inverter in proper system for high power application and controller is used DSP(TMS320C31). The effectiveness of proposed system confirmed the validity through SPICE simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2846-2848
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• 2005

This paper proposes a pattern classification algorithm for the defect distribution of Hard Disk Drive (HDD). In the HDD productions, the defect pattern of defective HDD set is important information to diagnosis of defective HDD set. In this paper, 5 characteristics are determined for the classification to six standard defect pattern classes. A fuzzy inference system is proposed, the inputs of which are 5 characteristic values and the outputs are the possibilities that the input pattern is classified to the standard patterns. Classification result is the pattern with maximum possibility. The proposed algorithm is implemented with a PC system for defective HDD sets and shows its effectiveness.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2528-2530
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• 2004

Neural network minimization problems are often conditioned and in this contribution way to handle this will be discussed. It is shown that a better conditioned minimization problem can be obtained if the problem is separated with respect to the linear parameters. This will increase the convergence speed of the minimization. One of the most powerful uses of neural networks is in function approximation(curve fitting)[1]. A main characteristic of this solution is that function (f) to be approximated is given not explicitly but implicitly through a set of input-output pairs, named as training set, that can be easily obtained from calibration data of the measurement system. In this context, the usage of Neural Network(NN) techniques for modeling the systems behavior can provide lower interpolation errors when compared with classical methods like polynomial interpolation. This paper solve of single-variable minimization using neural network.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.1043-1048
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• 1990

The degenerate case of multivariable hyperbolic distributed-parameter systems (systems of hyperbolic partial differential equations) in time coordinate t and space coordinate x is characterized by a property that all the characteristic curves of the state equations are parallel to the coordinate axes of independent variables. It is a disturbing fact, although not well known, that the so-called maximum principle as applied to these systems does not exist for the control that depend on time alone. In this paper, however, it is shown that a set of necessary conditions in the small can exist for unconstrained as well as magnitude constrained controls in a locally convex set. The necessary conditions thus derived can be used conveniently to find the optimal control for degenerate hyperbolic distributed-parameter control systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1381-1385
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• 2000

In this paper, a guideline of axial flow fan design for noise reduction of refrigerators is p resented. Refrigerators have components which have a role to screen particular frequency air borne-noise which is generated by an axial flow fan set in them. Effective ways to use the particular characteristic of refrigerators are shown in this study. As a result of application of the methods, we reduced the noise of the target systems by more than 3 dB(A) from the viewpoint of air-borne noise produced by the axial flow fan set.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.12
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• pp.65-73
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• 1995

In this paper, new algorithm which calculates transmission coefficient of electromagnetic wave by numerical analysis of scattered field by conductors with arbitrary cross-sections in parallel-plate waveguide is proposed. Proposed algorithm assumes magnetic current distribution on the boundary of scattering conductors, and applies Image theorem to perfect conductor surfaces of parallel-plate waveguide. Integral equations for fictitious magnetic currents on conducting boundary are set up. Magnetic current distributions on conducting boundary are expanded as exponential basis function, and using Galerkin method matrix equations are set wp. To compute matrix elements this method utilizes Fourier transform which is faster than numerical integration. Finally, frequency and incidence-angle characteristic of transmission coefficient are calculated and compared with experimental results.

• Bulletin of the Korean Mathematical Society
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• v.34 no.4
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• pp.595-601
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• 1997

Let $C_d$ be the rational curve of degree d in $P_k ^3$ given parametrically by $x_0 = u^d, X_1 = u^{d - 1}t, X_2 = ut^{d - 1}, X_3 = t^d (d \geq 4)$. Then the defining ideal of $C_d$ can be minimally generated by d polynomials $F_1, F_2, \ldots, F_d$ such that $degF_1 = 2, degF_2 = \cdots = degF_d = d - 1$ and $C_d$ is a set-theoretically complete intersection on $F_2 = X_1^{d-1} - X_2X_0^{d-2}$ for every field k of characteristic p > 0. For the proofs we will use the notion of Grobner basis.