• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.144-147
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• 2001

This paper presents adaptive fuzzy controller which is uncertainty or unknown variation in different parameters with nonlinear system of helicopter. The proposed adaptive fuzzy controller applied TSK(Takagi-Sugeno-Kang) fuzzy system which is not only low number of fuzzy rule, and a linear input-output equation with a constant term, but also can represent a large class of nonlinear system with good accuracy. The adaptive law was designed by using Lyapunov stability theory. The adaptive fuzzy controller is a model reference adaptive controller which can adjust the parameter $\theta$ so that the plant output tracks the reference model output. First of all, system of helicopter was considered as stopping state, and design of controller was simulated from dynamics equation with stopping state. Results show that it is controlled more successfully with a model reference adaptive controller than with a non-adaptive fuzzy controller when there is a modelling error between system and model or a continuous added noise in such unstable system.

• Proceedings of the IEEK Conference
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• 2000.07a
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• pp.62-65
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• 2000

In this paper we propose skewed angle detection methods for images that contain text that is not aligned horizontally. In most images text areas are aligned along the horizontal axis, however there are many occasions when the text may be at a skewed angle (denoted by 0 < ${\theta}\;{\leq}\;{\pi}$). In the work described, we adapt the Hough transform, Shadow and Threshold Projection methods to detect the skewed angle of text in an input image using the orthogonal angle view property. The results of this method are a primary text skewed angle, which allows us to rotate the original input image into an image with horizontally aligned text. This utilizes document image processing prior to the recognition stage.

• Structural Engineering and Mechanics
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• v.44 no.4
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• pp.487-499
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• 2012

Dynamic instability of beams subjected to periodic axial forces is studied using the discrete singular convolution (DSC) method with the regularized Shannon's delta kernel. The principal regions of dynamic instability under different boundary conditions are examined in detail, and the non-stationary vibrations near the stability-instability critical regions have been investigated. It is found that the results obtained by using the DSC method are consistent with the analytical solutions, which shows that the DSC algorithm is suitable for the problems considered in this study. It was found that there is a narrow region of beat vibration existed in the vicinity of one side (${\theta}/{\Omega}$ > 1) of the boundaries of the instable region for each condition.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.4
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• pp.1194-1201
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• 1996

For the case of creep-fatigue interaction, the damage zone developed in front of the growing crack-tip during creep regime is important because it can affect the damage mechanism to be occured by the following fatigue load. These are studied in theis paper through proper consideration of the cavitiy-size dependent sintering stress which is approximated by polynomials. It is shown that the inclination of reversed damage zone size with respect to the applied load parameter can be explained by considering realistic sintering stress distribution. However, the resultant stress field has $r^{1/2+\theta}$ singularity, regardliss of the profile of variable sintering stress, which is the same to that case solved for constant sintering stress.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.52
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• pp.337-345
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• 1999

The long-tailed, positively skewed exponential distribution can be made into an almost symmetric distribution by taking the exponent of the data. In these situations, to use the traditional shewhart control limits on an individuals chart would be impractical and inconvenient. The transformed data, approximately bell-shaped, can be plotted conveniently on the individuals chart and exponentially weighted moving average chart. In this paper, using modifying statistics with transformed exponential of the data, we give a method for constructing control charts. Selecting method of exponent for individual chart is evaluated. And consider that smaller weight being assigned to the older data as time process and properties and taking method of exponent($\theta$), weighting factor($\alpha$) are suggested. Our recommendation, on the basis result of simulation, is practical method for EWMA chart.

• Journal of the Korean Magnetics Society
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• v.2 no.2
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• pp.125-131
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• 1992

기판회전 테이블이 부착된 DC, RF-magnetron sputtering 장치로 유리기판 위에 제작한 1000 .angs. 정도의 8.8 .angs. Tb/X .angs. Fe (X=5.4~11.0) 다층박막에 관하여 시료진동형 자 기계와 타원편광 분석장치를 사용하여 자화, 수직자기이방성, kerr 회전각의 Fe층 두께와 열처리 온도 의존성이 연구되었다. Fe층 두께가 7.8 .angs. 기점으로하여 자화용이축의 전이가 나타나기 시작하여 6.4 .angs. 일때 수직자기이방성을 나타낸다. 실험치로부터 계산한 Fe와 Tb층의 경계면 수직이방성 에너지 $K_{s}$ = -0.38 erg/$cm^{2}$이고, Fe층만의 체적수직이방성 에너지 $K_{v}$ = -8.50 * $10^{5}$ erg/$cm^{3}$이다. Polar Kerr 회전각은 Fe층 두께 7.8 .angs. 에서 그대값 2 .THETA. $_{k}$ = 1.22 .deg. 를 갖는다.다.다.다.

• The Journal of Natural Sciences
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• v.14 no.2
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• pp.25-31
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• 2004

레이저 거리 측정기나 화생탐지 라이다용으로 사용할 수 있는 눈에 안전한 적외선 레이저 광원을 개발하였다. 펌프레이저로는 소형 플래쉬 램프로 구동되는 Nd:YAG 레이저를 사용하였으며, OPO(Optical Parametric Oscillator) 결정으로는 Flux 성장된 KTP를 사용하였다. OPO 송진기는 레이저 공진기 내부에 설치하여 비선형 광학 현산에 의한 파라메트릭 발진이 쉽게 일어나도록 하였다. 효율적인 파라메트릭 발진을 위해서 Type II 비임계 위상정합$(\theta=90^{\circ},\;\phi = 0^{\circ})$을 사용하여 공진기를 구성하였다. Nd:YAG 레이저는 Cr:YAG 결정을 사용하여 수동형 큐-스위칭 되었으며 OPO 출력은 1mJ 정도이었다. OPO 펄스폭은 4ns로서 수동형 큐스위칭 레이저 펄스폭보다 20% 정도로 작았다. OPO 출력의 펄스폭이 펌프레이저의 펄스폭 보다 작은 것은 이론적 계산을 통하여 확인할 수 있었다.

• Proceedings of the SCSK Conference
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• 2003.09b
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• pp.357-368
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• 2003

II-A isotherms and phase behaviors of 'tocomide', a newly synthesized 1,3-bis(N-(2-hydroxyethyl)-tocopherol succinylamino)-2-hydroxypropane, mixed with cholesterol and linoleic acid, was studied for its monolayer miscibility and a stable delivery formulation for antioxidant applications. The monolayer of tocomide and cholesterol was formed in a homogeneously mixed state at air-water interface. The ternary mixtures with linoleic acid showed various bulk structures, including a stable and transparent solution of thermodynamically stable lamellar phase. The lamellar structure was confirmed by the X-ray diffraction (XRD) patterns and polarized microscopy such that pure tocomide formed a liquid crystal at room temperature with a lamellar periodicity of 36.7 $\AA$(2$\theta$=2.41$^{\circ}$).

• Proceedings of the IEEK Conference
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• 2001.06e
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• pp.131-134
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• 2001

This paper proposes a stable control rule for nonlinear unicycle-type mobile robot. The control method uses a local error coordinate system, velocity and distance constants $\kappa$$\_$x/, $\kappa$$\_$y/, and he. Stability of control rule is proved Liapunov function. System input to the mobile robot is reference posture ($\chi$$\_$r/, y$\_$r/, $\theta$$\_$r/)/sup/ $\tau$/ and reference e velocity (ν$\_$r/,$\omega$$\_$r/)$\^$$\tau$/. System output of the mobi-le robot is velocity of driving wheels. We introduce limit velocity for preventing high initial speed. From simulation results, we can see the proposed control rule is stable.

• Journal of the Korean Chemical Society
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• v.8 no.2
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• pp.65-67
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• 1964

The partition function of liquid fluorine were developed by applying the theory of significant structures in liquids. The molar volume, vapor pressure, entropy of vaporization and surface tension of the liquid were calculated over a wide temperature range. The critical properties for the liquid were also calculated. The results show good agreement with experimental observations.