• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.90-95
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• 2001

f-$\theta$len is one of the important parts in Laser Scanning Unit because it affects on the optical performance of Laser Scanning Unit dominantly. It is necessary to find out the relationship between the surface profile error of f-$\theta$lens and the beam profile focusing on the Organic Photo Conductive drum in order to analysis the beam profile problems such as appearance of side lobe and expansion of center lobe. In this research, a simulation process which relates the surface profile characteristics to the beam profile has been developed by CODE V. The simulated beam profile also have been compared with the measurement results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.9
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• pp.1227-1233
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• 2021

QR Code has been used in various forms such as simple business cards and URLs. Recently, the influence of Corona 19 Fundemik has led to the use of QR Codes to track travel routes through visits and entry / exit records, and QR Code usage has skyrocketed. In this way, most people have come to use it in the masses and are constantly under threat. In the case of QR Code, you do not know what you are doing until you execute it. Therefore, if you undoubtedly execute a QR Code with a malicious URL inserted, you will be directly exposed to security threats. Therefore, this paper provides a cloud-based malware QR Code detection system that can make a normal connection only when there is no abnormality after determining whether it is a malicious QR Code when scanning the QR Code.

• The Transactions of the Korea Information Processing Society
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• v.7 no.7
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• pp.2149-2160
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• 2000

Recently many efforts on the development of automatic processing system for delivery sequence sorting have been performed in ETRI, which requires the use of postal4-state bar code system to encode delivery points. The 4-state bar code called postal 4-state barcode for high speed processing that has been specifically designed for information processing of logistics and automatic processing of he mail items. The Information of 4-state bar code indicates mail data such as post code, delivery sequence number, error correction code worked, customer information, and a unique ID. This appear addresses the issue on he reduction of reading error in postal 4-state raster beam based bar code reader. The raster beam scanning features are the unequally distributed number of spots per each unit, which cause reading errors. We propose a method for reducing the bar code reading error by adjusting measured values of bar code width to its average value over each interval. The test results show that the above method reduces the average reading error rate approximately by 99.88%.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.5
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• pp.566-571
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• 1988

Laser scanning system using a hologram is simpler in optical system, lower in cost than using a polygon. In this paper, a thick hologram is fabricated for the underfilled transmission disk type with a merit of wabble insensitivity to vibration. High diffraction efficiency over 50% is obtained using silver halide recording material. The two-dimensional scan pattern with 13 scan-line is made by 7-facet hologon and mirror system. This system can be practically applied to POS(Point of Sale) bar-code symbol reader.

• Applied Microscopy
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• v.44 no.2
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• pp.74-78
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• 2014

Dislocation density and distribution in epitaxial GaAs layer on Si are evaluated quantitatively and effectively using image processing of transmission electron microscopy image. In order to evaluate dislocation density and distribution, three methods are introduced based on line-intercept, line-length measurement and our coding with line-scanning method. Our coding method based on line-scanning is used to detect the dislocations line-by-line effectively by sweeping a thin line with the width of one pixel. The proposed method has advances in the evaluation of dislocation density and distribution. Dislocations can be detected automatically and continuously by a sweeping line in the code. Variation of dislocation density in epitaxial GaAs films can be precisely analyzed along the growth direction on the film.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.10a
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• pp.554-559
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• 1999

The purpose of this study is the machining of texture shapes by the contour fitting data. The hardware of the system comprises PC and scanning system, CO2 laser machine. There are four steps, (1) text image loading using scanning shapes or 2D image files, (2) generation of contour fitting data by the line and arc, cubic Bezier curve, (3) generation of NC code from the contouring fitting data, (4) machining by the DNC system. It is developed a software package, with which can conduct a micro CAM system of CNC laser machine in the PC without economical burden.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.311-316
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• 2008

Thick-walled cylinders, such as a cannon or nuclear reactor, are autofrettaged to induce advantageous residual stresses into pressure vessels and to increase operating pressure and the fatigue lifetimes. As the autofrettage level increases, the magnitude of compressive residual stress at the bore also increases. The purpose of the present paper is to predict the accurate residual stress of SCM440 high strength steel using the Kendall model which was adopted by ASME Code. Hydraulic pressure process was applied and thick-walled cylinders were autofrettaged up to 30% overstrain levels. Electro polishing was performed to get more accurate data. Residual stresses were measured by X-ray diffraction method. The autofrettaged surface which was plastically deformed analyzed using a scanning electron microscope(SEM). Although there were some differences in measured residual stress and numerical, there is a tendency to agree.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.346-349
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• 1993

A method for image compression based on decomposition is presented. We design the efficient coding technique for upper band image signals. This coding technique with directive 1-D DPCM is based on the statistical properties of upper bands. Lower band image signals is encoded using 2-D DPCM. The directive 1-D DPCM is performed, scanning upper bands according to edge direction. And then the predicted error signals of upper band sis coded using B1 and Huffman code, and the predicted error signals of lower band is coded using Huffman code. The proposed system shows improved performance when compared with other existing methods with respect to peak signal to noise ratio(PSMR) and human visual system(HVS) properties.

• Journal of the Korean Institute of Telematics and Electronics
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• v.7 no.3
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• pp.5-11
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• 1970

Some of the coding method have been discussed by extracting characteristics from vowels and consonants of Korean characters. given letters were sampled through 3$\times$5 mesh and also constituted first matrix system which taken subpatterns of vertical Conponent as variables and then, characteristics of the letters are extracted from the second matrix system expresses by common characteristics which are combined-with first one. Single coding was obtained by scanning the characteristic pattern. a good agree between theoretical values and their measurements and the reproducing of all vowels and consonants of Korean chasacters about coding were certified on the display designed.

• Proceedings of the Korean Society of Computer Information Conference
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• 2024.01a
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• pp.239-240
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• 2024

본 논문에서는 모바일 기기에 티켓을 발매하는 발권 애플리케이션을 설계 및 구현하였다. 애플리케이션은 사용자가 웹 인터페이스를 통해 메뉴 선정과 결제를 완료하여 모바일 기기로 QR 코드 식권을 발급받도록 구현한다. 식권 결제는 PG 연동을 통해 이루어지며, 식권 코드의 유효성은 코드 스캐닝을 통해 실시간으로 검증되도록 구현한다. 그리고 관리자가 식권 판매와 사용 현황을 확인할 수 있는 모니터링 기능을 구현한다.