• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.1260-1262
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• 2010

IPTV 는 대표적인 방송통신융합 산업으로 IT 망의 양방향성을 이용한 서비스의 차별화를 내세우며 여러 사업자에 의해 서비스가 이루어지고 있다. 기존 유선 통신망을 중심으로 제공되어 왔던 IPTV 서비스는 최근 모바일 환경 등으로 그 영역을 확대하기 위해 연구가 진행되고 있으며, 다른 한편으로는 IPTV 서비스를 위한 플랫폼 등을 개방하여 사업자가 아닌 일반인도 IPTV 를 통한 방송을 할 수 있는 구조인 Open IPTV 에 대한 연구가 활발하다. 이러한 Open IPTV 환경에서는 다수의 컨텐츠 제공자가 존재하기 때문에 기존 IPTV 에서 사용 되는 특정 기기 혹은 스마트카드를 통한 사용자 인증 및 키 분배가 어려운 실정이다. 따라서 본 논문에서는 Open IPTV 환경에서 안전한 컨텐츠 전송을 위한 사용자 인증 및 키 분배 시스템을 제안하고자 한다.

• Journal of Digital Contents Society
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• v.13 no.2
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• pp.151-157
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• 2012

Even though the protective facility is well made with the development of medicine, the spatial dose within the radiation section could increase the exposure of the workers. The spatial dose is always present in distribution room within the Department of Nuclear Medicine, so the spatial dose of the interior distribution room is measured and analyzed for the prediction of the exposure dose. The spatial dose rate was $6.78{\pm}0.083{\mu}Sv/h$ in the $^{18}F$ distribution room of department of Nuclear Medicine, $9.248{\pm}0.013{\mu}Sv/h$ in $^{99m}Tc$, and $^{131}I$ distribution room. In addition, in case of $^{18}F$ distribution room, the yearly external exposure dose was $42.5{\mu}Sv$ when the nurse does IV in 1m in distance. It also showed that the spatial dose rate on the direction of right oblique showed higher than others by the standard of distribution window of distribution room. Therefore, the staying time of the workers should be short during distributing radiopharmaceuticals in the distribution room and the design of the distribution protection is necessary to reduce the exposure in the direction of right oblique of the protection. The utmost endeavors are required to reduce the worker's individual exposure dose while doing IV.

• The Korean Journal of Pesticide Science
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• v.17 no.2
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• pp.107-116
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• 2013

Polar pesticides like pymetrozine (log $P_{ow}$: -0.18) are known to be difficult to analyze. The analytical method of pymetrozine using hydromatrix included in the official method of KFDA was uncommon and provided ambiguous evidence to confirm both the identity and the quantity. Therefore, precise single residue analytical method was developed in representative crops for using liquid-liquid extraction (LLE). The pymetrozine residue was extracted with methanol from 11 representative crops which comprised apple, blueberry, broccoli, cabbage, cherry, crown daisy, hulled rice, Korean cabbage, potato, rice and watermelon. The extract was purified serially by liquid-liquid extraction (LLE) and silica solid phase extraction (SPE). For rice and hulled rice samples, n-hexane partition was additionally adopted to remove nonpolar interferences, mainly lipids. The residue levels were analyzed by HPLC with DAD, using $C_8$ column. LOQ (limit of quantitation) of pymetroizinie was 1 ng (S/N > 10) and MQL (method quantitation limit) was 0.01 mg/kg. Mean recoveries from 11 crop samples fortified at three levels (MQL, 10 ${\times}$ MQL and 50 ${\times}$ MQL) in triplicate were in the range of 83.1~98.5% with coefficients of variation (CV) of less than 10%, regardless of sample type, which satisfies the criteria of KFDA. The method established in this study could be applied to most of crops as an official and general method for analysis of pymetrozine residue.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1065-1079
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• 2014

The ultimate behavior of reinforced concrete corbel is complicated due to the primary design variables including the shear span-to-effective depth ratio a/d, flexural reinforcement ratio, load condition, and material properties. In this study, a simple indeterminate strut-tie model reflecting all characteristics of the ultimate strength and complicated structural behavior is proposed for the design of the reinforced concrete corbels with shear span-to-effective depth ratio of $a/d{\leq}1$. A load distribution ratio, defined as the fraction of applied load transferred by horizontal truss mechanism, is also proposed to help structural designers perform the design of reinforced concrete corbels by using the strut-tie model approaches of current design codes. For the development of the load distribution ratio, numerous material nonlinear finite element analyses of the proposed indeterminate strut-tie model were conducted by changing primary design variables. The ultimate strengths of reinforced concrete corbels tested to failure were evaluated by incorporating the proposed strut-tie model and load distribution ratio into the ACI 318-11's strut-tie model method. The validity of the proposed model and load distribution ratio was examined by comparing the strength analysis results with those by the ACI 318-11's conventional design method and strut-tie model methods of current design codes.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.142-146
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• 2014

The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction of nine components system was investigated by distribution equilibrium. The model coal tar fraction comprising NHC group (NHCs; indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine(Qu)), bicyclic aromatic compound group (BACs; 1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN)), biphenyl (Bp) and phenyl ether (Pe) and the aqueous methanol were used as the raw materials and the solvent of this work, respectively. A batch-stirred tank was used as the liquid-liquid contact unit of this work. The distribution coefficient of NHCs increased by increasing the equilibrium operation temperature, whereas the selectivity of NHCs with respect to BACs decreased. Decreasing the initial volume ratio of water to the solvent resulted in deteriorating the selectivity of NHCs in reference to BACs, but improving the distribution coefficients of NHCs. At a fixed experimental condition, the sequence of the distribution coefficient and the selectivity with reference to BACs for each groups was increased in order of NHCs > Bp > BACs > Pe and NHCs > Bp> Pe, respectively. Also, the sequence of the distribution coefficient for entire compounds was in order of In > iQ = Q > Qu > Bp > 1MN = 2MN > Pe > DMN. The maximum yield of NHCs and the selectivity of NHCs based on BACs obtained by methanol extraction were 94 and 23%, respectively. Furthermore, the recovery process for NHCs from coal tar was studied by using the experimental results from this work.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.54-60
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• 2007

We constructed a fiber-optic temperature sensor system using a sensor array with 15 fiber Bragg gratings for distributed temperature monitoring in electrical power systems. A polynomial fitting algorithm was used to compensate the nonlinear action of the MEMS tuneable wavelength filter used for Bragg wavelength demodulation Fixed passband wavelengths from a Fabry-Perot ITU filter were used as reference wavelengths for the fitting algorithm which obtained constant accuracy regardless of the wavelength scanning range and frequency. About 0.18[%] of linearity error compared to reference thermocouple thermometer has been obtained in the preliminary experimental results.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.576-576
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• 2016

치수경제성분석, 투자우선순위 및 시설물 규모결정 등의 의사결정과정에서 실무에서는 다차원 홍수피해산정법(MD-FDA)을 현재까지 널리 사용 중이다. 2004년에 개발된 MD-FDA는 대상지역의 자산규모를 행정구역 경계 최소단위인 "읍면동"을 기준으로 계산하여 취합하고, 대상자산이 위치가능한 토지이용정보를 토지피복도로부터 확인하여, 읍면동내 토지이용공간면적을 기준으로 자산정보를 분배(분해)하는 방식으로 이루어진다. 그러나 읍면동 단위의 공간적인 범위는 상당한 면적의 공간적 경계이기 때문에, 이를 평균적인 밀도데이터로 분배 시 공간적인 자산분포에 대해 정밀도를 담보할 수 없다. 이에 본 연구는 행정구역경계인 "읍면동"과 비교할 때 평균적으로 1/30의 면적을 가지는 집계구 단위의 센서스 공간정보자료를 이용하여 방법론을 개선하였고, 이를 MD-FDA 분석체계를 근간으로 센서스자료와 관계된 자료들 간의 연계 및 전체적인 분석과정을 정립하였다. 본 연구에서 제안한 방법을 경기도 동두천시를 대상으로 적용하여 기존 방법에 의한 피해액과 그 차이를 비교하였고, 도로명전자지도의 실제 건물객체 자료(.shp)를 기준으로 오차율을 확인한 결과, 기존 방식에 비해 정밀도가 월등히 향상된 것을 확인할 수 있었다.

• Communications for Statistical Applications and Methods
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• v.19 no.3
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• pp.315-331
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• 2012

In this research, we estimated the number of hits per song and its sampling error from 11 (areas including Gangnam) based on log data compiling the number of hits collected from offline karaoke players in March 2011. Then, we calculated the monetary equivalent of the sampling error under the current system that distribute royalties from the karaoke players to copyright holders(song writers and arrangers) according to the estimated hits. Because of the small sample size, the estimated number of hits had a very large sampling error. This research proposes a more reasonable sample design to estimate the usage of copyrighted music works for a fair distribution of royalties by reducing sampling error.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.74-80
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• 2004

If the withdrawal force of strand driven roll which is controlled with predetermined speed isn't distributed regularly in continuous casting process, mold level is changed cyclically and slab quality is not good. In this paper, both casting speed control and load sharing control algorithm of strand driven roll according to ratio which is set up by operator at same time is proposed. The proposed algorithm is to share the withdrawal force by following torque current of each driven roll as average torque current by changing speed reference of each driven roll motor. The load sharing control with anti-wind up for improvement transient state is adopted and the proposed algorithm is implemented in POSCO pilot caster.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.8
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• pp.721-728
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• 2009

Equal/unequal 4-way power divider suitable for satellite communication using SIW technology is presented in this paper. The control of positions of guiding posts provides equal or unequal power division ratios by maintaining the width of the SIW unchanged. In addition, the detailed descriptions for the proposed power divider include the general characteristics of radial waveguide, feeding part using coaxial cable, simple SIW structure, power-guiding posts, and transition for measurement. The comparison between the simulated and measured data shows a good agreement at a center frequency of 10 GHz. The measured input impedance bandwidths for equal and unequal power divisions are about 2.1 GHz and 3 GHz under the condition of less than VSWR 2:1, respectively.