• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10a
• /
• pp.591-595
• /
• 1990

This paper describes a method of aisle following of a mobile robot using machine vision. As a navigation guide, Black strip painted on the lower part of wall of aisle is used. The offset of the vehicle position from the center of aisle and the heading angle are determined from the binary image of guide strip captured by a CCD camera. To remove the effect of noise. i.e. break of guide strip for the door or reflection of light, pixel sampling method together with consistency check of the incline for the sampled pixels is used.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 1997.04a
• /
• pp.152-159
• /
• 1997

An analytical method is developed to study the propagation of surface waves across infilled trenches. The Green's function technique is used to estimate the reflection and transmission coefficients of Rayleigh waves across a semi-infinite plate inserted between two homogeneous quarter-spaces. After validating the method against experimental data, influence of the material contrast and the angle of incidence on the screening effectiveness of an infilled trench is examined.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.290-292
• /
• 2007

A twisted nematic type liquid crystal electro-optic modulator (TN-LC modulator) was developed. The modulator used single polarizer and the reflection on-off ratio was maximized by optimization of twist angle and retardation of liquid crystal cell. The TNLC modulator shows better sensitivity and response time than conventional liquid crystal modulator.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.54 no.9
• /
• pp.407-413
• /
• 2005

The optical current transformer was developed for 170 kV GIS using optical fiber. The sensor optimized on the optical CT was wound 3 turns and twisted 4 times per a turn at the pipe with a diameter of 130 m. To optimize the optical CT, the output signal was measured according to the setting angle of polarizer and analyzer, The asymmetry and distortion of the output signals were improved when the parallel polarized light was incident to the fiber sensor and under the angle of analyzer was $45^{o}$. The measurement error for the linearity was only $\pm{0.42}\;\%$ to 1,000 A in the case of reflection type.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.40 no.6
• /
• pp.590-597
• /
• 1991

Ion reflective index and sheet resistance in the silicon oblique range smaller than 8 degree and optimization of annealing temperature have been studied. A four point probe was used to obtain the sheet resistance after annealing, while high resolution SIMS was used to determine the Boron and Fluorine atomic profiles before and after annealing. Experimental results and theory of ion reflective index are compared. Ion reflective index was found to decrease according to increasing an ion oblique angle. We introduce a simple analytical model ion reflection, concidering the Rutherford scattering model. This result can not be explained by the conventional Gaussian model.

• Journal of the Optical Society of Korea
• /
• v.18 no.6
• /
• pp.685-690
• /
• 2014

Microholographic gratings were prepared on an aluminum oxide ($Al_2O_3$) surface using a 140-fs pulse at a center wavelength of 800 nm. The $Al_2O_3$ was deposited on a silicon wafer and on indium tin oxide glass to a thickness of approximately 25 nm using an atomic layer deposition process. The silicon wafer substrate exhibited reflection-type gratings that were measured as a function of the incidence angle. The diffraction efficiency of the fabricated gratings was measured, with a maximum diffraction efficiency of 45% at an incidence angle of approximately $30^{\circ}$.

• Journal of Information Display
• /
• v.1 no.1
• /
• pp.48-51
• /
• 2000

In this work, we proposed a reflective antiferroelectric liquid crystal display (AFLCD) using a half-wave cell whose inplane tilt angle is $22.5^{\circ}$. To check the validity of our design, we fabricated a reflective half-wave AFLC cell of which inplane tilt angle is $24.9^{\circ}$, and measured VIS reflection spectra, contrast ratio and response time. In the results, the half-wave AFLC cell in the reflective configuration exhibits high brightness, high contrast ratio of 20:1, and fast response time of $700{\mu}s$.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.25 no.3
• /
• pp.163-170
• /
• 2005

A modular Gaussian beam model is developed to simulate some ultrasonic testing configurations where multiple interfaces are involved. A general formulation is given in a modular matrix form to represent the Gaussian beam propagation with multiple interfaces. The ultrasonic transducer fields are modeled by a multi-Gaussian beam model which is formed by superposing 10 single Gaussian beams. The proposed model, referred to as "MMGB" (modular multi-Gaussian beam) model, is then applied to a typical contact and angle beam testing configuration to predict the output signal reflected from the corner of a vertical crack. The resulting expressions given in a modular matrix form are implemented in a personal computer using the MATLAB program. Simulation results are presented and compared with available experimental results.

• Proceedings of the KIEE Conference
• /
• 1999.07e
• /
• pp.2057-2059
• /
• 1999

This paper describes the phenomena of the refraction and reflection when the ultrasonic signals generated by PD(Partial Discharge) in a transformer propagate through the boundary between insulating oil and the tank of the transformer. In this paper, considering the characteristic of the ultrasonic signal and the velocity of the propagation in medium, propagation time from PD source to sensor for incidence angle was calculated. As a result, it was found that the shortest time at specific angle exists. Taking into account the velocity of the propagation in medium, the shortest time with a computer was simulated. It was shown that the simulation was same as experimental result at a real PD source in the transformer.

• Journal of the Optical Society of Korea
• /
• v.20 no.6
• /
• pp.739-744
• /
• 2016

We have designed a new TIR(Total Internal Reflection) structure for generating an LED lens which can produce a rectangular beam with small divergence angle in two perpendicular directions for an optical guidance system. The lens can control the divergence angle in the horizontal direction to be a small value of about $8^{\circ}$ with a $1mm{\times}1mm$ LED source, also in the vertical direction it can be about $7^{\circ}$, with optical collection efficiency higher than 0.83. After the lens is manufactured, the work demonstrates that the lens is suitable for an optical guidance system.