• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.10a
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• pp.293-295
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• 2015

국제항로표지협회(IALA)는 항로표지 국제표준을 개발하기 위해 항로표지의 설치 및 관리를 주관하는 기관으로 구성된 비정부 간 국제기구로서, e-Navigation을 고려하여 항로표지 분야의 정보 표준 개발을 위해 국제수로기구(IHO)의 S-100 표준을 적용하기로 결정하고, S-200의 이름으로 표준개발 작업을 수행하고 있다. 이 중에서 S-201 AtoN 표준은 항로표지 정보 담당기관이 관리하고 있는 항로표지 정보를 교환할 때 적용할 수 있는 표준으로, IALA가 IHO와 협력하여 중점적으로 개발하고 있는 표준이며, 해양수산부와 선박해양플랜트연구소는 IALA와 S-201 표준개발 협력에 합의하고, S-201 표준개발 작업을 진행 중에 있다. 본 논문에서는 S-100 표준의 기본 개념과 함께 IALA에서 개발 중인 S-201 개발 경과를 소개하고, S-201 표준 개발로 인해 예상할 수 있는 기대효과를 정리하였다.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.259-264
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• 2012

Automatic magnetic abrasive polishing (MAP), which can be applied after machining of a mold on a machine tool without unloading, is very effective for finishing a free-form surface such as a complicated injection mold. This study aimed to improve the efficiency of MAP of a non-ferrous mold surface. The magnetic array table and control of the electromagnet polarity were applied in the MAP of a free-form surface. In this study, first, the magnetic flux density on the mold surface was simulated to determine the optimal conditions for the polarity array. Then, the MAP efficiency for polishing a non-ferrous mold surface was estimated in terms of the change in the radius of curvature and the magnetic flux density. The most improved surface roughness was observed not only in the upward tool path but also in the working area of larger magnetic flux density.

• Composites Research
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• v.12 no.2
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• pp.53-61
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• 1999

A failure criterion must be considered in each failure mode and loading condition to provide easy determining strength parameters, flexibility and rational simplicity. In this study, new failure criterion was developed by introducing equivalent strength under biaxial loading of tension and torsion. The experimental results showed that the equivalent biaxial strength has a power law relation with respect to a parameter, cos($tan^{-1}R_b$). Failure strength under biaxial loadings could be predicted as a function of tensile strength, torsional strength and biaxial ratio. The scattering of experimental data could be predicted using a Weibull distribution function and the concept of equivalent biaxial strength. Also, in this study, a fatigue theory was developed based on a plane stress model which enabled the S-N curve for combined stress states to be predicted from the S-N data for uniaxial loading. The prediction models can be predicted a biaxial strength and fatigue life of general laminated composite naterials under multi-axial loadings.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.137-143
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• 1997

This study was carried out to investigate the effect of godulbaegi leaf extracts on detoxication of liver injury in $CCl_4$-treated rats. We divided normal group(5) and $CCl_4$-treated group and then $CCl_4$- treated group was divided into 6 groups; only $CCl_4$-treated group(CS), aqueous extract pretreated group (CSA), n-butanol extract pretreated group(CSB), Tween 80 pretreated group(CT), n-hexane extract pretreated group(CTH) and ethyl acetate extract pretreated group(CTE). The ratio of liver weight per body weight and the activity of GPT in hexane extract group(CTH) were lowest, similar to the results of S. Godulbaegi n-hexane extract(IS) groups intoxicated by $CCl_4$ had lower values of MDA than CS and CT which are control groups. Histological finding of liver tissue revealed less of necrosis in IS extracts groups than in control groups(CS, CT). From these results, IS extracts could predominently prevent hepat-otoxicity of rats. Especially, hexane extract was effective on the detoxication of liver injury among the other extracts.

• Korean Journal of Optics and Photonics
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• v.9 no.2
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• pp.76-85
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• 1998

Organic single crystal of p-toluene sulfonate(PTS) bulks and thin films were fabricated using a slow solution evaporation method. Third and fifth order nonlinear refractive indices, $n_2$and $n_3$, of PTS crystals at 1600 nm were determined by the Z-scan method and the multimode output of the PTS thin film waveguide was observed at 1350 nm. When the beam intensity is in 2-5 GW/$cm^2$, the nonlinear refractive indices are $n_{2}=6{\times}10^{-4}cm^{2}$/GW and $n_{3}=-7{\times}10^{-5}cm^{4}/GW^{2}$ and the two and three photon absorption coefficients are zero. When the beam intensity is in 5~16 GW/$cm^2$, the split-step fast Fourier transform beam propagation method simulation shows that the beam propagation in the PTS is distorted from the gaussian shape.

• Journal of Energy Engineering
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• v.2 no.2
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• pp.225-230
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• 1993

Isothermal vapor-liquid equilibrium data have been measured for binary systems n-dodecane-1-defanol, n-doderane-1-dodecanol, and 1-decanoi-1-dodecanol at 140$^{\circ}C$ by using head space gas chromatography (H.S.G.C) as a static method. The activity coefficients, calculated taking into acount the nonideality of the liquid phase, were correlated with the conventional g$\^$E/ model, Margules, van Laar, Wilson, NRTL equations. These equilibrium data were thermodynamically consistent by Rrdlich- kister test, among these data, system n-dodecane-1-detanoi has minimum azeotrope.

• Journal of the Institute of Convergence Signal Processing
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• v.14 no.4
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• pp.249-254
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• 2013

A fast multiplier and ADC are essential to process the analog signals in real time. The double-base number system(DBNS) is known as an efficient method for this purpose. The DBNS uses the numbers 2 and 3 as the base numbers simultaneously. The system has an advantage of fast multiplication, less chip area, and low power consumption compared to the binary multiplier. However, the inherent errors of the log number's intrinsic tolerance in DBNS are accumulated in a FIR digital filter, so the signal-to-noise ratio(SNR) has a tendency to be degraded. In this paper, the nonlinear encoder of ADC is designed to compensate the accumulated errors of DBNS by analysing the error distributions of various filter coefficients. The new ADC does not sacrifice its own advantages because the encoder circuits are modified only. The experiments were done with an FIR filters those were designed to have -70dB of SNR in stop band. The proposed nonlinear ADC encoder could drop the SNR to -45dB in stop band, in contrast to -35dB with the linear encoder.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.52-58
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• 1996

본 연구에서는 반응성 마그네트론 스퍼터 이온플래이팅법에 의해 Co계 합금인 stellite 6B 기판 위에 증착된 TiN 박막의 증착특성을 조사하였다. 증착된 박막의 증착속도는 기판에 인가된 bias 가 증가함에 따라 박막의 치밀화와 resputtering으로 인해 감소하였으며 박막의 형상은 bias가 인가되지 않은 상태에서의 open columnar 구조에서 bias가 인가된 경우 columnar 구조가 사라진 매끈하고 치밀한 구조로 변화하였다. 기판 bias가 인가된 경우 N/Ti 조성비는 거의 stoichiometry를 만족하였으며 증착된 박막의 우선성장 방위는 $N_2$의 양이 감소할 수록 (200)에서 (111)로, bias 증가에 따라서는 (200)에서 (111)을 거쳐 (220)으로 변화하였다. 박막의 경도는 박막이 압축응력을 나타낼수록 증가하였으며, bias가 인가된 경우 약 2000~3300kgf/$\textrm{mm}^2$의 높은 경도를 나타내었다.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.145-150
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• 2012

This study was conducted to measure methane ($CH_4$) and nitrous oxide ($N_2O$) emissions from the 6 month old litter stockpile used for korean native cattle (Hanwoo) from August 3, 2007 to October 4, 2007. Daily mean $CH_4$ emissions was peaked to 273.013 ${\mu}g\;m^{-2}\;s^{-1}$ (SE : ${\pm}1.047{\mu}g\;m^{-2}\;s^{-1}$) on first day and then gradually decreased to 2.309 ${\mu}g\;m^{-2}\;s^{-1}$ (SE : ${\pm}0.061{\mu}g\;m^{-2}\;s^{-1}$) at the end of this experiment. Daily mean $N_2O$ emissions was as little as 0.269 ${\mu}g\;m^{-2}\;s^{-1}$ (SE : ${\pm}0.018{\mu}g\;m^{-2}\;s^{-1}$) on first day, but exponentially increased up to 3.569 ${\mu}g\;m^{-2}\;s^{-1}$ (SE : ${\pm}0.454{\mu}g\;m^{-2}\;s^{-1}$) on 43rd day and then slowly decreased to 1.888 ${\mu}g\;m^{-2}\;s^{-1}$ (SE : ${\pm}0.012{\mu}g\;m^{-2}\;s^{-1}$) at the end of this experiment. Carbon dioxide equivalent ($CO_2$-eq), calculated by global warming potentials of $CH_4$ or $N_2O$, of $CH_4$ on first day occupied approximately 99% of sum of $CO_2$-eq of $CH_4$ and $N_2O$. Methane emissions decreased and $N_2O$ emissions increased so that $CO_2$-eq ratio of $CH_4$ to $N_2O$ was 50:50 on 34th day. The effect of $N_2O$ on the ratio was increase thereafter. The ratio of daily mean $CH_4$ and $N_2O$ emissions to daily error of the mean was calculated to find daily fluctuation of $CH_4$ and $N_2O$ emissions. The ratio of $CH_4$ was less than 1.0% till 11th day but increased to 10.9% on 57th day. The ratio of $N_2O$ (0.4%~51.0%) was higher than that of $CH_4$, showing high in early stage and then gradually decrease, which was different from the pattern of $CH_4$. The ratio of daily mean emissions to daily error of the mean was little in case of active $CH_4$ or $N_2O$ generation period, which would be caused by the temporal and spatial heterogeneity of composting process. Hence more air supply on early stage to decrease $CH_4$ generation and proper turning to reduce spatial heterogeneity are needed to mitigate greenhouse gas emissions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2875-2882
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• 2013

The design of PN(Pseudo Noise) sequences with good cross-correlation properties is important for many research areas in communication systems. Also analyses of cross-correlation frequency between designed sequences have been researched. In this paper we analyze of cross-correlation distribution and properties of non-linear binary sequences family $S^r=\{Tr^m_1\{[Tr^n_m(a{\alpha}^t+{\alpha}^{dt}]^r\}{\mid}a{\in}GF(2^m),0{\leq}t < 2^n-1\}$, where $gcd(r,2^m-1)=1$ with 5-valued cross-correlation.