• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.337-339
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• 2015

대기오염물질 배출은 다른 오염물질과는 다르게 일단 배출하고 나면 대기 중으로 빠르게 확산되어 단속이 어렵다. 또한 현장 적발하였다하더라도 시료채취가 어려워 적극적인 대기 오염행위 적발, 단속을 위한 지도 점검 및 관련법 개선이 필요하다. 본 논문에서는 대기오염방지를 위해 배출되는 대기오염물질을 측정하고 오염도를 신속히 파악하여 대기오염을 사전에 방지하는 측정방법에 대하여 연구한다. 이를 위하여 휴대가 간편한 스마트폰으로 사진을 찍고 DOM 방법으로 혼탁도를 계산하는 안드로이드 네이티브앱을 설계하고 구현한다.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.5 s.23
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• pp.67-74
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• 2002

The geometriccorrection of a satellite imagery is performed by making a systematic correction with satellite ephemerides and attitude angles followed by employing the Ground Control Points (GCSs) or Digital Elevation Models (DEMs). In a remote area or an inaccessible area, however, GCPs are unavailable to be surveyed and thus they can be obtained only by reading maps, which are not accurate in reality. In this study, we performed the systematic correction process to the inaccessible area and the precise geometric correction process to the adjacent accessible area by using GCPs. Then we analyzed the correlation between the two geo-referenced Korea Multiurpose Satellite (KOMPSAT-1 EOC) images. A new geometrical correction for the inaccessible area imagery is achieved by applying the correlation to the inaccessibleimagery. By employing this new method, the accuracy of the inaccessible area imagery is significantly improved absolutely and relatively.

• Journal of the Korean Society for Precision Engineering
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• v.4 no.3
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• pp.60-68
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• 1987

An optoelectronical method for in process monitoring of flank wear of cutting tools is presented. The method is based upon real-time vision technology in which the tool is illuminated by a beam of laser and then the image of wear zone is taken by a vidicon camera. The image is converted to a series of digital pixel data and processed through an algorithm specially developed for measurement of the wear land width. Detailed aspects of the prototype measurement system byilt for experiment are described, and test results are discussed. As conclusions, it is proved that the methods are effec- tive especially for-in situ application with a measuring accuracy of 0.01mm.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.77-83
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• 2021

Solid oxide fuel cell (SOFC) operates at high temperatures in range of 600-800℃. Since layers of SOFC are composed of different substances, different thermal expansion in SOFC can result in defects under high temperature conditions. For understanding relation between temperature field and the thermal deformation in SOFC, temperature and strain field were simultaneously estimated using thermographic phosphors by optical measurement. Temperature fields were obtained by the life-time method, and the temperature differences of one specimen was checked with thermocouple. The thermal deformation was estimated by digital image correlation (DIC) method with extracted phosphorescence images. To investigate the deformation accuracy of DIC measurement, thermographic phosphors were coated with and without grid pattern on aluminum surface. Simultaneous measurement of temperature fields and thermal deformation were carried out for YSZ. This study will be helpful to multi-sensing of temperature field and thermal deformation on SOFC cells.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.148-156
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• 1996

Automatic product system is gradually increasing according to development of industrial society. On-line measurement makes a important role in view of economic and effective side in industrial product system. Syncronization system is developed to measure screw thread which is rotating. In-process measuring of rotating body have a lot of difficuties even thoufht using various method containing high speed camera. So, now we suggest one of the new method which is not so expansive. In this study, digital value was produced through the image processing algorithm from acquired orignal image. As a result, we have a good agreement between measuring values calculated from image conture and measuring values acquired from profile project by means of experiment, respectively.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.191-197
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• 2011

In this paper, we have designed an integrated triplexer which is the basic component for a FTTH(Fiber To The Home) system which can transmit CATV and voice/data at the same time in a single fiber. The integrated triplexer can be fabricated with a novel technique of "Micro-Block Stacking (MBS)" method which automatically aligns the optical components in the optical beam pass using accurate ceramic holders. We analyze the displacement of the optical focus according to the tolerances of the component dimensions and the assembly process using code V simulator. For the transmitter, the most serious shift of the focal points is caused by the displacements of the LD spot. So the focal point moves up to $72{\mu}m$ from the center point for ${\pm}25{\mu}m$, ${\pm}25{\mu}m$, ${\pm}30{\mu}m$ displacements. For the receiver the most serious shift of the focal points is caused by the displacements of a 0.8mm ball lens (for the analog receiving part) and a micro ball lens (for the digital receiving part), and the focal point moves up to $55{\mu}$ for ${\pm}55{\mu}m$, ${\pm}5{\mu}m$, ${\pm}55{\mu}m$ micro ball lens displacements.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.339-344
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• 2016

Since transmissions of large amounts of data are frequent, users require more bandwidth, and the need for communications networks having greater bandwidth is increasing. One communications network satisfying this need is an optical communications network. Therefore, studies to increase the transmission capacity of optical communications systems have been carried out. However, in a general optical communications system, a signal transmitted through optical fiber (a transmission medium) is detected through direct detection in the receiving system. This method has a disadvantage in that the entire bandwidth of the optical signal cannot be utilized. Also, when transmitting an optical signal, there is a problem where the signal-to-noise ratio is affected by neighboring channels. To overcome this situation, various studies are being conducted to minimize the influence of external interference and noise. This paper overcomes the situation by transmitting spectrum-sliced signals using the digital transmission system, FSK. Analyzing the characteristics of the signals detected in the receiver of the optical communications system, Gaussian distribution is used for the PDF of the spectrum-sliced signal, and the signal at the receiving end of the optical communications system is assumed to have a k-square distribution. The results of the analysis confirmed it is better to transmit the spectrally divided signal rather than transmit the laser source.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.497-502
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• 2001

We propose a method to represent binary data by modulating both the intensity and the phase of uniform plane waves with a twisted-nematic liquid crystal display for holographic digital data storage especially in a disk-shaped recording medium. As far as intensity modulation is concerned, our method is not different from the conventional method, because binary bit values 0 and 1 are represented by the dark (off) and lit (on) states of the liquid crystal display pixels, respectively (or vice versa). With our method, however, the on pixels are also controlled so that the beams passing through them can have one of two different phase delays. If the difference of the two phase delays is close to 180 degrees, we can reduce the dc component of the data image and thus improve the beam intensity uniformity at the holographic recording plane when Fourier plane holograms are recorded. The feasibility of our method is experimentally demonstrated.

• Korean Journal of Optics and Photonics
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• v.13 no.6
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• pp.493-500
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• 2002

Fingerprint recognition is concerned with fingerprint acquisition and matching. Our research was focused on a fingerprint matching method using an inkless fingerprint input sensor at the fingerprint acquisition step. Since an inkless fingerprint sensor produces a digital-image-processed fingerprint image, we did not consider noise that can happen while acquiring the fingerprint. And making the user attempt fingerprint input as random, we considered image distortion that translation and rotation are included as complex. NJTC algorithm is used for fingerprint identification and verification. The method to find the center of the fingerprint is added in the NJTC algorithm to supplement discrimination of fingerprint recognition. From this center point, we decided the optimum cropping size for effective matching with pixels and demonstrated that the proposed method has high discrimination and high efficiency.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.3
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• pp.16-33
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• 1993

New decoding algorithm of double-error-correction Reed-Solmon codes over GF(2$^{8}$) for optical compact disks is proposed and decoding algorithm of RS codes with triple-error-correcting capability is presented in this paper. First of all. efficient algorithms for estimating the number of errors in the received code words are presented. The most complex circuits in the RS decoder are parts for soving the error-location numbers from error-location polynomial, so the complexity of those circuits has a great influence on overall decoder complexity. One of the most known algorithm for searching the error-location number is Chien's method, in which all the elements of GF(2$^{m}$) are substituted into the error-location polynomial and the error-location number can be found as the elements satisfying the error-location polynomial. But Chien's scheme needs another 1 frame delay in the decoder, which reduces decoding speed as well as require more stroage circuits for the received ocode symbols. The ther is Polkinghorn method, in which the roots can be resolved directly by solving the error-location polynomial. Bur this method needs additional ROM (readonly memory) for storing tthe roots of the all possible coefficients of error-location polynomial or much more complex cicuit. Simple, efficient, and high speed method for solving the error-location number and decoding algorithm of double-error correction RS codes which reudce considerably the complexity of decoder are proposed by using Hilbert theorems in this paper. And the performance of the proposed decoding algorithm is compared with that of conventional decoding algorithms. As a result of comparison, the proposed decoding algorithm is superior to the conventional decoding algorithm with respect to decoding delay and decoder complexity. And decoding algorithm of RS codes with triple-error-correcting capability is presented, which is suitable for error-correction in digital audio tape, also.