• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.10
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• pp.1-6
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• 2009

We derive the phase error of hologram due to imperfection of a wave plate, the azimuth angle error of a wave plate, and the azimuth angle error of a linear polarizer. Also, we analyze the effect of phase error by the modified triangular interferometer in case of 3-D image reconstruction of hologram.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.12
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• pp.1-9
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• 2013

A standalone LED lighting system in using solar energy has been used usually less than 70W of lighting power because of a troublesome installation and maintenance. In this system, as more and more LED lighting power increases, the capacity of photovoltaic panel does proportionally, and to improve the charging efficiency of solar energy, MPPT(Maximum Power Point Tracking) techniques is used frequently, but the solar tracker is not. In this paper, a solar tracker which traces the light of the sun in varying hour to hour is studied to apply to the standalone LED lighting system. This solar tracker consists of twin axis for tracing the azimuth and altitude respectively, and it has a robust structure with safe mode to stand a strong wind. As a result of analysis, generating efficiency of the traced type has improved on the fixed one 28.84% on average.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.703-705
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• 1999

In this paper, we introduce the direction of arrival(DOA) estimation of distributed signal based on the improved ESPRIT algorithm. Most research on the estimation of DOA has been performed based on the assumption that the signal sources are point sources. However, we consider a two-dimensional distributed signal source model using improved ESPRIT algorithm. In the distributed signal source model, a source is represented by two parameters, the azimuth angle and elevation angle. We address the estimation of the elevation and azimuth angles of distributed sources based on the parametric source modeling in the three-dimensional space with two uniform linear arrays. The array output vector is obtained by integrating a steering vector over all direction of arrival with the weighting of a distributed source density function. We also develop an efficient estimation procedures that can reduce the computational complexity. Some examples are shown to demonstrate explicity the estimation procedures under the distributed signal source model.

• Corrosion Science and Technology
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• v.3 no.3
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• pp.102-106
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• 2004

Al foil used was 99.9 and 99.99 %. Test solution used was NaCl solution. The noise was determined using controlled potential electrolysis at -200 and -700 mV vs. NHE. The current fluctuation was caused by breakdown and repaired process of aluminum oxide film. The current fluctuation value of noise was proportion to degree of growth. The number of noise was proportion to the number of pit. The examining of current flutulation value and number of noise could be evaluated corrosion. A 99.99 % Al foil was the mostly crystal of {100} plane, and showed three-dimensional, as azimuth pit with along the direction of this place piled up. A 99.9 % Al foil was polycrystal, and in order of (311) >(222) >(200) >(111) plane. The azimuth pit did not occurred as the dissolution was occurred from each plane.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.625-630
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• 2006

A new method to get reliable viewing angle measurements on LCD reflective display is presented. This method is based on the use of commercial Fourier optics viewing angle instruments already proposed by ELDIM for more than 15 years. This apparatus is capable to measure simultaneously quasi all the incidence and azimuth angles and to control very precisely the illumination of the sample. We show that, in contrast to other instruments, a clever illumination procedure with two different conditions allows separation of the intrinsic reflective contribution of the display and of the parasitic front end reflection. In this way, intrinsic performances of the display can be obtained at any incidence and azimuth angles and realistic observer conditions can be simulated.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.114.5-114
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• 2001

In this paper, the model for personal navigation system using low-cost inertial sensors and error compensation method with GPS are proposed. Simulation is accomplished for the performance test. WNS(Walking Navigation System) is a kind of personal navigation using the number of a walk, stride and azimuth. Because the accuracy of these variables determines the navigational performance, computational methods have been investigated. The step is detected using the motion pattern by walking motion, stride is determined by neural network and azimuth is calculated with gyro´s output. The neural network filters off unnecessary motions. However, error compensation method is needed, because the error of navigation information increases with time ...

• Proceedings of the IEEK Conference
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• 2002.06e
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• pp.113-116
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• 2002

In this paper, we propose the sound-mapping algorithm of the detected obstacle by ultrasonic sensors. We apply this algorithm to a Obstacle alarm for the visually impaired. In our system, we acquire obstacles information using ultrasonic sensors, and transform two-dimensional and distance information into sound-imaging information and vibrator with azimuth (direction) and distance. We implement this system with ultrasonic sensors to more effective expression of the obstacle information. The distance of an obstacle can be expressed by sound pressure level, and azimuth of the obstacles can be expressed by inter-aural time difference (ITD) and inter-aural level difference (ILD) that are two important cues in a binaural system. These are the principal cues for sound localization, to detect sound source. In this system, the obstacle is substituted with a sound source. The visually impaired receive sound information of obstacles by headphone.

• Journal of Information Display
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• v.8 no.4
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• pp.10-14
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• 2007

LCD performance is generally evaluated in terms of luminance and color versus viewing angle. In the present paper, we show that this type of display can be favorably characterized in terms of polarization. We show that ELDIM EZContrast instrument which is routinely used for viewing angle measurements can be upgrade for measuring the polarization state of the light at each incidence and azimuth angle. More precisely, the degree of polarization of light, its ellipticity and polarization direction can be measured at each incidence angle between 0 and $88^{\circ}$ and for all the azimuth angles (from 0 to $360^{\circ}$). Important differences between the displays can be detected and related to their internal structures when luminance and color profiles are quite similar. The same setup can also be used to characterize optical components of the LCDs.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.165-165
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• 2000

The sunlight tracking and reflexing system can be divided into two parts. One is a sunlight tracking system and the other is a sunlight reflexing system. The sunlight tracking system detects an azimuth angie and an elevation angle of the sun using 2-axis sensor sun tracker. The sunlight reflexing system controls a reflection mirror to be reflected a sunlight at the target area after getting the azimuth angle and the elevation angle of the sun from the sunlight tracking system. We applied the fuzzy PID controller to control the reflexing mirror.

• Korean Journal of Remote Sensing
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• v.31 no.4
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• pp.331-336
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• 2015

In this study, a numerical model developed for sunshine duration based on GIS data was used. This model considers blocking caused by topography and buildings and it is properly applicable to evaluation of sunshine duration environment in urban areas. The model reasonably well predicted the solar altitude and azimuth angels, compared to those provided by Korea Astronomy and Space Science Institute (KASI). The developed model was applied to evaluation of sunshine duration environment around the Seonleung Park located near a building-congested area in Seoul. The model well reproduced shadow caused by buildings and/or topography in the numerical domain at 09:00 on August 1, 2015. In addition, the model was applied to finding a suitable measurement sites for pyrheliometer around the Seonleung Park. The model was also usefully applied to finding a suitable site for pyrheliometer in an urban area.