• Journal of Ecology and Environment
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• 제34권2호
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• pp.193-202
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• 2011

We studied temperature sensitivity characteristics of soil respiration during periods of rising and falling temperatures within a common temperature range. We measured soil respiration continuously through two periods (a period of falling temperature, from August 7, 2003 to October 13, 2003; and a period of rising temperature from May 2, 2004 to July 2, 2004) using an open-top chamber technique. A clear exponential relationship was observed between soil temperature and soil respiration rate during both periods. However, the effects of soil water content were not significant, because the humid monsoon climate prevented soil drought, which would otherwise have limited soil respiration. We analyzed temperature sensitivity using the $Q_{10}$ value and $R_{ref}$ (reference respiration at the average temperature for the observation period) and found that these values tended to be higher during the period of rising temperature than during the period of falling temperature. In the absence of an effect on soil water content, several other factors could explain this phenomenon. Here, we discuss the factors that control temperature sensitivity of soil respiration during periods of rising and falling temperature, such as root respiration, root growth, root exudates, and litter supply. We also discuss how the contribution of these factors may vary due to different growth states or due to the effects of the previous season, despite a similar temperature range.

• 한국레이저가공학회지
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• 제13권4호
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• pp.14-20
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• 2010

Robot path generation and laser welding technology for manufacturing automotive body are studied. Laser welding and industrial robot systems are used with the robot based laser welding system. The laser system used in this study is 1.6kW Fiber laser, while the robot system is 6 axes Industrial robot (payload: 130kg). The robot based laser welding system is equipped with laser scanner system for remote laser welding. The laser source, robot and laser scanner system are used to increase the processing speed and to improve the process efficiency. The welding joints of steel plate are butt and lapped joints. The quality test of the laser welding are through the observation the shape of bead on plate and cross-section of welding part. The 3 dimensional laser welding for non-linear pipe welding line is performed. This paper introduces the robot based laser welding system to resolve the limited welding speed and accuracy of the conventional spot welding system.

• 동의생리병리학회지
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• 제27권3호
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• pp.299-305
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• 2013

This study was to evaluate the single dose toxicity of Arecae Semen (AS) in male and female ICR mice. Aqueous extracts of AS (Yield = 13.15%) were administered as an oral dose of 2,000, 1,000 and 500 mg/kg (body weight) according to the recommendation of Korea Food and Drug Administration (KFDA) guidelines. Animals were monitored for the mortality and changes in body weight, clinical signs and gross observation during 14 days after dosing, upon necropsy; organ weight and histopathology of 12 principle organs were examined. We could not find any mortality, clinical signs, and changes in the body and organ weight except for diarrhea. Diarrhea were observed in all three different dosage groups of male mice, and in 2000 mg/kg groups of female mice within 48hrs after administration. In addition, no AS extract related abnormal gross findings and changes in histopathology of principle organs were detected except for some sporadic accidental findings. Although the 50% lethal dose and approximate lethal dose of AS aqueous extracts in female and male mice were detected as over 2,000 mg/kg - the limited highest dosage recommended by KFDA guidelines. It should be carefully used in clinics because AS may be induced severe digestive tract disorders.

• Biomolecules & Therapeutics
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• 제17권3호
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• pp.325-331
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• 2009

The object of this study was to evaluate the single oral dose toxicity of Low Molecular Weight Fucoidan (LMF) in male and female rats. LMF was administered to female and male SD rats as an oral dose of 2,000, 1,000 and 500 mg/kg (body wt.). Animals were monitored for the mortality and changes in body weight, clinical signs and gross observation organ weight and histopathology of 14 principle organs were examined upon necropsy. As the results, no LMF treatment related mortalities, clinical signs, changes on the body and organ weights, gross and histopathological observations against 14 principle organs were detected up to 2,000 mg/kg in both female and male rats except for some sporadic findings not LMF treatment related toxicological signs. Therefore, $LD_{50}$ (50% lethal dose) and approximate LD of LMF after single oral treatment in female and male rats were considered over 2,000 mg/kg - the limited dosages recommended by KFDA Guidelines [2005-60, 2005], respectively.

• Plant Biotechnology Reports
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• 제2권3호
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• pp.199-206
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• 2008

We have developed an efficient system of assessing the ability of a gene silencing cassette to silence transcripts from recalcitrant or poorly studied plant species by using a model plant as a host for the gene of interest. Tobacco plants transgenic for Lachrymatory Factor Synthase (LFS) enzyme activity from onion were first produced by introducing a CaMV 35S-onion-lfs gene construct. These plants were then subjected to a second transformation with an RNAi construct directed against the lfs gene sequence. LFS enzyme activity assay showed that the transgenic plants, containing both the lfs gene and the RNAi construct, had significantly reduced LFS activity. This observation was supported by Western analysis for the LFS protein and further validated by quantitative RT-PCR analysis that demonstrated a significant reduction in the lfs transcript level in the dual transformants. In this work, we have demonstrated that the RNAi construct is a suitable candidate for the development of a non-lachrymatory onion. Our model plant RNAi system has wide-reaching applications for assessment and targeting of plant secondary pathway genes, from poorly studied or recalcitrant plant species, that are important in the pharmacological, food and process industries.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.638-643
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• 2002

MODIS (MODerate-resolution Imaging Spectroradiometer) onboard the first Earth Observing System (EOS) satellite, Terra, was launched successfully at the end of 1999. The direct broadcast MODIS data has been received and utilized in Korea Meteorological Administration (KMA) since february 2001. This study introduces utilizations of this data, especially for the derivation of sea surface temperature (SST). To produce the MODIS SST operationally, we used a simple cloud mask algorithm and MCSST algorithm. By using a simple cloud mask algorithm and by assumption of NOAA daily SST as a true SST, a new set of MCSST coefficients was derived. And we tried to analyze the current NASA's PFSST and new MCSST algorithms by using the collocated buoy observation data. Although the number of collocated data was limited, both algorithms are highly correlated with the buoy SST, but somewhat bigger bias and RMS difference than we expected. And PFSST uniformly underestimated the SST. Through more analyzing the archived and future-received data, we plan to derive better MCSST coefficients and apply to MODIS data of Aqua that is the second EOS satellite. To use the MODIS standard cloud mask algorithm to get better SST coefficients is going to be prepared.

• 물과 미래
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• 제28권2호
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• pp.137-143
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• 1995

해안 대수층 내에서 담수와 해수 사이에 형성되는 확산대의 위치와 형태는 많은 변수들에 의하여 영향을 받는다. 현재까지 수행된 많은 연구는 확산대들의 정성적 비교로 국한되었다. 본 연구에서는 정량적 분석을 위하여 확산대 특성(최대 침투 길이, 두께, 성층 정도)을 계량화하고 수치 모형을 이용하여 주요 변수(유속과 확산지수)가 확산대 특성에 미치는 영향을 고찰하였다. 차원해석을 통하여 정리된 실험 결과는 유속과 확산지수가 확산대의 특성에 미치는 영향을 명확히 규명하였다. 유속의 증가는 확산계수를 증가시키기 때문에 확산대가 팽창한다는 일부의 주장과는 달리 확산대는 축소하는 것으로 밝혀졌다.

• 한국멀티미디어학회논문지
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• 제14권7호
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• pp.949-963
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• 2011

무선 센서 네트워크상에서 센서노드의 소프트웨어 변경, 패치 등의 작업을 위해서는 일반적으로 센서노드 별로 ISP(In System Programming)를 이용하여 프로그램 해야 한다. 이는 네트워크 내에 존재하는 노드의 수가 소량인 경우 크게 문제되지 않지만, 대량의 노드로 구성된 경우에는 프로그래밍을 위한 시간적인 측면과 투여되는 인력적인 측면에서 매우 높은 비용이 소요된다. 본 논문에서는 현재 많이 사용하고 있는 IEEE 802.15.4 기반의 단일 홉 무선 센서 네트워크 환경에서 노드의 수와 무관하게 고속 병렬로 센서노드 내부의 프로그램을 무선으로 업데이트 할 수 있는 기법을 제시하고 실험을 통하여 그 성능을 검증한다.

• 한국멀티미디어학회논문지
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• 제19권12호
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• pp.1909-1918
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• 2016

This paper presents a unified framework for joint Convolutional Neural Network (CNN) based vehicle detection by leveraging multi-spectral image pairs. With the observation that under challenging environments such as night vision and limited light source, vehicle detection in a single color image can be more tractable by using additional far-infrared (FIR) image, we design joint CNN architecture for both RGB and FIR image pairs. We assume that a score map from joint CNN applied to overall image can be considered as confidence of vehicle existence. To deal with various scale ratios of vehicle candidates, multi-scale images are first generated scaling an image according to possible scale ratio of vehicles. The vehicle candidates are then detected on local maximal on each score maps. The generation of overlapped candidates is prevented with non-maximal suppression on multi-scale score maps. The experimental results show that our framework have superior performance than conventional methods with a joint framework of multi-spectral image pairs reducing false positive generated by conventional vehicle detection framework using only single color image.

• 한국인지과학회:학술대회논문집
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• 한국인지과학회 2005년도 춘계학술대회
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• pp.23-27
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• 2005

언어 특히 의미에 대한 연구와 마음의 구조를 연구하는 인지과학이 어떻게 중요한 관계를 가지고 발전하는가를 살펴보기로 한다. 언어의 구조는 마음의 구조의 일부라고 본 촘스키의 입장에 동조하면서도 의미의 구조에 대해서 소극적인 입장에 서는 그의 입장에서 자유롭게 벗어나 발전하고 있는 의미에 대한 연구를 조명하고 전망하기로 한다. 언어의 의미는 내면적(internal)인 것인가 외부적(external)인 것인가 의미 내용(content)과 맥락(context)의 관계는 어떠한가, 왜 정보구조가 중요한가 등을 점검한다.