• The Journal of Society for e-Business Studies
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• v.13 no.4
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• pp.1-16
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• 2008

LBS (Location Based Service) cannot be realized unless we can obtain the user's current location. Therefore, in order to realize indoor LBS, many researchers have been working on WLAN (Wireless Local Area Network) based indoor positioning and tracking. Meanwhile, Kalman filter has been widely used in the field of GPS based outdoor user tracking. The main purpose of this paper is proposing an extended Kalman filter method for indoor tracking. Our experimental results show that Kalman filter can be used to improve the accuracy of the measured tracks and the track can be further improved by making use of the map information.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.2
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• pp.147-154
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• 2003

The close-range photogrammetry is a surveying technique the acquiring the 3D object from 2D geometric appearance shown in the image. Camera treatment is relatively so simple. Camera position refer to the object can be freely adjusted by locating the exposure station at any site. So it is used effectively on a small area or object for survey. In this study, using the digital camera which has capacity of keeping numerical value by itself and easy carrying, we analyze the positioning error according to various change of photographing condition. Also we try to find a effective method of acquiring basis data for 3D monitoring of high-accuracy in sub-pixel degree thorough digital close-range photogrammetry with bundle adjustment for local terrain model generation.

• Journal of the Institute of Convergence Signal Processing
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• v.18 no.1
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• pp.25-30
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• 2017

Currently, most of the grain sorter uses CCD optic camera to find defective products. The aim of this paper is to use the CCD camera, and aim for improving the sorting power of the grain separator by using NIR(Near Infrared Radiation) sensor based on moisture content measurement algorithm. We intend to develop a system to develop an NFC imaging system in real time by developing an NIR imaging system and developing the grain sorter system that is considered to be defective in real time by checking the internal moisture content of the raw material in the real time.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.4
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• pp.387-402
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• 2014

In congested urban areas, constructions of tunnel structures have became necessary due to a lack of surface space. The excavation of any tunnel generated the ground disturbances of surrounding ground and displacements is major concern. Therefore, a study of tunnel stability is necessary. In this study, the authors have investigated the stability and failure pattern of tunnel through the model tunnel test. In this study, the close range photogrammetry was used to measure the ground deformation. The measured data was converted to displacement vectors and contours. And then it compared to FE analysis and empirical formula. In addition, this study presented the comparison between steel pipe reinforced model tunnel and unreinforced model tunnel. The ground deformation for both the steel pipe reinforced model tunnel and the unreinforced model tunnel was analysed.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.59-63
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• 2009

Purpose: To investigate the near horizontal heterophoria of the college students in their twenties on north Kyonggi Province. Methods: The all subjects had not experienced any ocular surgery and have no disease and their mean age is 22.9. As 122 subjects, they are 50 emmetropes and 72 ametropes. The ametropes are all myopia. After distance visual acuity correction with subjective and objective refraction test, evaluated their horizontal heterophoria with red maddox rod. Results: In maddox rod test, the subjects consist of orthophoria 4.9%, esophoria 9.8% and exophoria 85.3%. In the emmetropes orthophoria is 8%, esophoria is also 8% and exophoria is 84%. In the ametropes orthophoria is 2.8%, esophoria is 11.1% and exophoria is 86.1%. The mean size of horizontal heterophoria is esophoria 3.59PD (prism diopter), exophoria 7.04PD and in the emmetropes esophoria is 3.25PD, exophoria is 6.60PD. In the ametropes esophoria is 3.75PD and exophoria is 7.34PD. Conclusions: In the emmetropoes the orthophoria is more than in the ametropes and the esophoria and exophoria is more in the ametropes. But the differences between the heterophoria and emmetropia or ametropia were not significant (p>0.05). The mean size of heterophoria is higher in the ametropes than in the emmetropoes. The distribution range of heterophoria is wider in the male subjects than the female subjects.

• 한국지형공간정보학회:학술대회논문집
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• 2004.10a
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• pp.155-160
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• 2004

근거리 디지털 영상을 이용하여 도로 사면의 3차원 변형을 효율적으로 측정하고자 하였다. 광속조정법(bundle adjustment)에 근거한 사진삼각측량 방법을 적용함에 있어서 종래의 표준적인 기법과 Free-net 기법으로 각각 처리하여 사면의 약 1/35000의 정확도로 3차원 측정과 변형량을 도출하였으며, 토털스테이션에 의해 측정한 결과와 비교하였다. 연구를 통하여 Free-net 기법을 적용함으로써 복잡한 산업현장에서 기존의 측지학적 기준점측량을 행하지 않고도 신속하고 정확한 측정을 기대할 수 있음을 확인할 수 있었다.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.274-275
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• 2003

광통신 분야의 연구 중 근거리 광통신 분야에 적용하기 위한 Plastic Optical Fiber(POF)에 관한 연구와 개발이 활발히 이루어지고 있다. POF의 광전송 특성을 결정짓는 요소 중 가장 중요한 특성이 바로 굴절률 분포이다. 이에 따라 그동안 다양한 형태의 POF 굴절률 측정 방법이 연구되어 왔다. 기존 Glass Optical Fiber의 굴절률 분포 측정 방법 중 가장 일반적이고 효과적인 방법 중 하나는 coherent 빛의 간섭을 이용한 transverse interferograms을 분석하는 방법으로 Fizeau 간섭계와 같은 간섭계를 이용하여 위상변화를 측정하고 측정한 위상을 tomography적인 해석방법을 통해 굴절률 분포를 계산하는 방법이다. (중략)

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.17-20
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• 2001

In this paper, we realized a transceiver system for short distance communication with a commercial RF module working in ISM band. Also we measured system performance by transmitting baseband data in a building and then we compared the demodulated data bits with stored data bits in a PC connected with demodulator. The RF module In the experiments works only in the bandwidth of 424MHz-429MHz. The signal level degrades as the distance between transmitter and receiver increases. We measured the signal level and bit error and present the measured results with various locations in the building. And it is concluded that the measured data may be used in the design of short distance network in a building.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.635-641
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• 2004

This paper presents a new low-cost RF Built-In Self-Test (BIST) circuit for measuring transducer voltage gain, noise figure and input impedance of 5.25GHa low noise amplifier (LNA). The BIST circuit is designed using 0.18${\mu}{\textrm}{m}$ SiGe technology. The test technique utilizes input impedance matching and output transient voltage measurements. The technique is simple and inexpensive. Total chip size has additional area of about 18% for BIST circuit.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.493-496
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• 2003