• Nuclear Engineering and Technology
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• 제48권1호
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• pp.189-199
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• 2016

Fast neutrons with a broad energy spectrum, with which it is possible to evaluate nuclear data for various research fields such as medical applications and the development of fusion reactors, can be generated by irradiating proton beams on target materials such as beryllium. To generate short-pulse proton beam, we adopted a deflector and slit system. In a simple deflector with slit system, most of the proton beam is blocked by the slit, especially when the beam pulse width is short. Therefore, the available beam current is very low, which results in low neutron flux. In this study, we proposed beam modulation using a buncher cavity to increase the available beam current. The ideal field pattern for the buncher cavity is sawtooth. To make the field pattern similar to a sawtooth waveform, a multiharmonic buncher was adopted. The design process for the multiharmonic buncher includes a beam dynamics calculation and three-dimensional electromagnetic simulation. In addition to the system design for pulsed proton generation, a test bench with a microwave ion source is under preparation to test the performance of the system. The design study results concerning the pulsed proton beam generation and the test bench preparation with some preliminary test results are presented in this paper.

• 한국임상약학회지
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• 제20권1호
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• pp.50-55
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• 2010

Cefetamet pivoxil is a prodrug of cefetamet possessing a broad spectrum of activity against many aerobic gram-positive and -negative organisms. Although many literatures in abroad had introduced its pharmacokinetics about two decays ago, no data have been revealed in Korean subjects. Therefore, this study was aimed to investigate the pharmacokinetics of cefetamet following a single oral administration of cefetamet pivoxil in Korean healthy volunteers. After an overnight fast, a tablet of cefetamet pivoxil (500 mg) was given to eight volunteers, and blood samples were serially taken up to 12 h. Plasma concentrations of cefetamet were determined by HPLC with UV detection. Cefetamet reached the peak concentration ($2.0{\pm}1.3\;{\mu}g/ml$) at $3.0{\pm}0.8$ h, and mono-exponentially decayed at a half-life of $2.6{\pm}0.9$ h. Three volunteers represented very low systemic exposure compared to the others, which provided very large inter-individual variation in Cmax, and AUC. The present results were discussed and reviewed with the previously published data, and a couple of points are suggested for clinical trials of this drug in Korean subject including bioequivalence study.

• 한국정보과학회논문지:시스템및이론
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• 제31권9호
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• pp.536-542
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• 2004

본 논문에서는 디지털 주파수 합성기의 구조에 대하여 연구하였다. 디지털 주파수 합성기는 높은 스펙트럼 순도로 빠른 주파수 전환이 가능하고, 현대의 확산 스펙트럼 무선통신 시스템에 널리 사용된다. 롬 기반의 디지털 주파수 합성기는 싸인 파형의 크기를 저장한 롬 테이블을 사용한다. 본 논문에서는 롬의 크기를 줄이는 세 가지 새로운 기술을 제안하였다. 새로운 기법 중 한 가지는 여러 개의 계층적 구조를 사용하였다. 다른 기법들은 계층적 롬 구조를 간단한 보간 기법으로 결합하였다. 이러한 기법으로 12비트의 싸인 파형을 생성하였다. 실험 결과 새롭게 제안한 기법은 기존 방법[1]에 비해 ROM 크기를 24%까지 줄일 수 있다.

• 융합신호처리학회논문지
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• 제12권1호
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• pp.33-37
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• 2011

본 논문은 FFT를 이용한 적외선 화재 열영상의 주파수 스펙트럼 분석에 관한 것으로 영상처리를 통하여 화재 발생 유무를 주파수 영역에서 판별하기 위한 조건을 도출하는 것이 목적이다. 적외선 열영상의 주파수 스펙트럼 분석은 고속 푸리에 변환을 이용하여 수행하였으며, 화재로 추정되는 고명도의 영역을 화재 후보영역으로 결정한 다음, 연속적인 열영상의 해당영역에 대하여 DC 및 AC 주파수 분포를 분석하였다. 분석된 결과를 기반으로 정적인 오검출 요소와 동적특성을 가지는 화재영역을 구분하는 열영상의 화재 판정 기준을 제시하고 컴퓨터 모의실험을 통하여 실용성을 확인하였다.

• Journal of the Optical Society of Korea
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• 제8권4호
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• pp.174-181
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• 2004

Various kinds of systems, that can do target recognition and position detection simultaneously by using infrared sensing detectors, have been developed. In this paper, the detection system TRSS (Thermal target Recognition by Spiral Scanning) adopts linear array shaped uncooled IR detector and uses spiral type fast scanning method for relative position detection of target objects, which radiate an IR region wavelength spectrum. It can detect thermal energy radiating from a 9 m-size target object as far as 200 m distance. And the maximum field of a detector is fully filled with the same size of target object at the minimum approaching distance 50 m. We investigate two types of lens systems. One is a singlet lens and the other is a doublet lens system. Every system includes one aspheric surface and free positioned aperture stop. Many designs of F/1.5 system with ${\pm}5.2^{\circ}$ field at the Efl=20, 30 mm conditions for single element and double elements lens system respectively are compared in their resolution performance [MTF] according to the aspheric surface and stop position changing on their optimization process. Optimum design is established including mechanical boundary conditions and manufacturing considerations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권8호
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• pp.3965-3983
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• 2017

We propose a novel eye tracking method that can estimate 3D world coordinates using an infrared (IR) stereo camera for indoor and outdoor environments. This method first detects dark evidences such as eyes, eyebrows and mouths by fast multi-level thresholding. Among these evidences, eye pair evidences are detected by evidential reasoning and geometrical rules. For robust accuracy, two classifiers based on multiple layer perceptron (MLP) using gradient local binary patterns (GLBPs) verify whether the detected evidences are real eye pairs or not. Finally, the 3D world coordinates of detected eyes are calculated by region-based stereo matching. Compared with other eye detection methods, the proposed method can detect the eyes of people wearing sunglasses due to the use of the IR spectrum. Especially, when people are in dark environments such as driving at nighttime, driving in an indoor carpark, or passing through a tunnel, human eyes can be robustly detected because we use active IR illuminators. In the experimental results, it is shown that the proposed method can detect eye pairs with high performance in real-time under variable illumination conditions. Therefore, the proposed method can contribute to human-computer interactions (HCIs) and intelligent transportation systems (ITSs) applications such as gaze tracking, windshield head-up display and drowsiness detection.

• 대한원격탐사학회지
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• 제25권6호
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• pp.487-499
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• 2009

Atmospheric correction of satellite measurements is a major step to estimate accurate surface reflectance of solar spectrum channels. In this study, Simplified Method for the Atmospheric Correction (SMAC) radiative transfer model used to retrieve surface reflectance from MODIS (MODerate resolution Imaging Spectrometer) top of atmosphere (TOA) reflectance. It is fast and simple atmospheric correction method, so it uses for work site operation in various satellite. This study attempts a test of accuracy of SMAC through a sensitivity test to detected error sources and to improve accuracy of surface reflectance using SMAC. The results of SMAC as compared with MODIS surface reflectance (MOD09) was represented that low accuracy ($R^2\;=\;0.6196$, Root Means Square Error (RMSE) = 0.00031, bias = - 0.0859). Thus sensitivity analysis of input parameters and coefficients was conducted to searching error sources. Among the input parameters, Aerosol Optical Depth (AOD) is the most influence input parameter. In order to modify AOD term in SMAC code, Stepwise multiple regression was performed with testing and remove variable in three stages with independent variables of AOD at 550nm, solar zenith angle, viewing zenith angle. Surface reflectance estimation by using Newly proposed AOD term in the study showed that improve accuracy ($R^2\;=\;0.827$, RMSE = 0.00672, bias = - 0.000762).

• 한국광학회지
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• 제13권5호
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• pp.414-420
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• 2002

본 연구에서는 bacteriorhodopsin(bR)이 첨가된 고분자 박막을 이용하여 광 논리회로 특성을 구현하였다. bR은 분광학적으로 구분되는 몇 단계의 중간단계로 구성된 복잡한 참순환 과정을 수반하고 있다. 우리는 bR의 광순환 과정중 B상태와 M상태의 흡수도 변화를 고려하여 He-Ne 레이저(632.8 nm)와 He-Cd 레이저(413 nm) 이용하여 광학적 논리회로를 구현하였다. 또한 B상태와 K상태간의 흡수 스펙트럼을 고려하여 He-Ne 레이저(632.8 nm)와 Nd-YAG 레이저의 제2고조파인 532 nm를 이용하여 고속 AND logic gate를 구현하였다.

• Earthquakes and Structures
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• 제16권6호
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• pp.641-654
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• 2019

This paper investigates the seismic response of a typical non-navigable continuous girder bridge isolated with friction sliding bearings of the Hong Kong-Zhuhai-Macao link projects in China. The effectiveness of the friction pendulum system (FPS) and accuracy of the numerical model were evaluated by a 1/20 scaled bridge model using shaking table tests. Based on the hysteretic properties of friction pendulum system (FPS), double concave friction pendulum (DCFP), and triple friction pendulum system (TFPS), seismic response analyses of isolated bridges with the three sliding-type bearings are systematically carried out considering soil-pile interaction under offshore soft clay conditions. The fast nonlinear analysis (FNA) method and response spectrum are employed to investigate the seismic response of isolated offshore bridge structures. The numerical results show that the implementation of the three sliding-type bearings effectively reduce the base shear and bending moment of the reinforced concrete pier, at the cost of increasing the absolute displacement of the bridge superstructure. Furthermore, the TFPS and DCFP bearings show better isolation effect than FPS bearing for the example continuous girder bridge.

• 디지털산업정보학회논문지
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• 제10권4호
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• pp.181-195
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• 2014

The game Industry has been a major leader in business world with its size and volume in terms of profit and culture contents, and ever increasing at the moment. Cloud Game has appeared as a new, combined game format, playable on smart TV and smart phone with its upgraded storage size and fast spreading N-screen. This research studies the present reality of the cloud industry by focusing on three categories which are device type, Platform, and game contents consequently in order to determine the future prospect of cloud games. First, the cloud game business will thrive as devices such as smart TV and smart phone are used widely. Second, the cloud game industry will have a new era when OS systems of Platform are united effectively. Third, the previous platform holders will have to face new challenges brought up by cloud games' service providers. Forth, the gamer, developer, and service provider need each other in order to widen the spectrum of business in cloud game industry.