• Proceedings of the KWS Conference
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• 2002.10a
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• pp.199-204
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• 2002

Extensive investigations on cast to cast variations observed in steels have underlined the role of thermocapillary or surface tension driven fluid flow in welding operations. The behavior of weld pool under the electric arc is however affected by possible arc modifications linked to microchemistry variations in materials & this limits to some extent the real contribution from surface tension effects. Thus, electron beam welding with high vacuum was used to investigate thermo-capillary effects on thin austenitic stainless steels & nickel based alloys. The weld pool was monitored by video observations to estimate the importance of fluid flow during the melting & solidification phase. The results underline the importance of fluid flow on [mal solidification.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.1
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• pp.85-90
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• 1987

Trench capacitors with four different structures were fabricated using plasma and reactive ion etching technique, and evaluated using their C-V and I-V characteristics. The results shows that the two step plasma etching technique is the best method to fabricate the trench capacitor because of its high breakdown field (~7.75 MV/Cm) and good step coverage. And the fixed oxide charges are comparable between the trench (3.6xE10/Cm\ulcorner~7.5xE10/Cm\ulcorner and the planar(4.5xE10/Cm\ulcorner~6.5E10/Cm\ulcorner capacitors.

• Analytical Science and Technology
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• v.19 no.1
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• pp.103-106
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• 2006

A 35-year-old Perubian who suffered from grand mal seizures died in the aircraft on his way from the United States to Hongkong via Incheon international airport of Korea. While performing the autopsy, 115 packs made with double layer of transparent film and black plastic bag containing cocaine were found in the ileum and large intestine. Among of them, 3 packs were ruptured. To determine the concentration of cocaine and its metabolites, blood, urine, bile, liver, spleen, heart, kidney, brain and gastric contents were taken and toxicological analysis was performed. Gas chromatography/mass spectrometry (GC/MS) following liquid-phase extraction using chloroform:isopropanol (=9:1) and derivatization with bis(trimethylsilyl)-trifluoroacetamide (contains 1% trimethylchlorosilane) was performed. High levels of cocaine, benzoylecgonine (BE) and ecgonine methylester (EME) were found in the postmortem blood (0.96, 3.09 and $5.59{\mu}g/mL$) and urine (32.85, 145.35 and $53.17{\mu}g/mL$), respectively. Cocaine and its metabolites were also detected in all other biological specimen.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.11
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• pp.82-90
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• 1995

This paper pressents a condition-based maintenance (CBM) method through bibration analysis. The well known frequency analysis is employed for performing machine fault diagnosis. The statistical control chart is also applied for analyzing the trend of the bearing wear. Vibration sensors are attached to prototype machine and signals are continuously monitored. The sampled data are utilized to evaluate how well the fast fourier transform(FFT) and the statistical control chart techniques could be used to identify defects of machine and to analyze the machine degradation. Experimental results show that the propowed approach could classify every mal-function and could be utilized for real machine diagnosis system.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.249-250
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• 2022

최근 API Call을 기반으로 하는 악성코드 탐지 및 분류에 대한 연구가 활발히 진행되고 있다. 그러나 API Call 기반의 데이터는 방대한 양과 다양한 차원의 특성으로 인해 분석과 학습 모델 구축 측면에서 비효율적인 한계가 있다. 이에 본 연구에서는 방대한 API Call 정보를 포함하고 있는 CICAndMal2020 데이터 세트를 대상으로 기존의 특성 선택 기법이 아닌 주성분 분석(Principal Component Analysis)을 사용하여 차원을 대폭 축소 시킨 후 머신러닝 기법을 적용하여 분류를 시도하였다. 실험 결과 전체 9,503개의 특성을 25개의 주성분(전체 대비 약 0.26% 수준)으로 축소시키고 다중 분류 기준 약 84%의 정확도를 나타냈다. 결과적으로 기존 연구에서의 탐지 모델 대비 정확도, F1-score 등의 성능 향상은 물론 차원 축소 측면에서 매우 향상된 결과를 달성하였다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.3
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• pp.199-210
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• 2011

This study was conducted to develop functional sources of herbal cosmetics for treatment of skin aging and inflammatory disorders using volatile flavor extracts of four different herbal medicinal prescriptions including Cnidium officinale Makino (COM), Angelica gigas Nakai (AGN), Mentha arvense L. (MAL), Artemisiae argyi Folium (AAF), Paeonia lactiflora Pall (PLP), Rehmanniae Radix Preparata (RRP), Scutellaria baicalensis Georgi (SBG), Panax ginseng C.A. Meyer (PGM), Glycyrrhiza uralensis Fisch (GUF). The volatile flavor extracts of four different herbal medicinal prescriptions (HH-1: COM, AGN, PLP, RRP, HH-2: COM, AGN, PLP, RRP, SBG, PGM, GUF, HH-3: COM, AGN, MAL, AAF, HH-4: COM, AGN, MAL, AAF, SBG, PGM, GUF) were extracted using SDE and their antioxidant and anti-inflammatory effects were measured by using DPPH radical and SLO, respectively. As a result, HH-2 showed moderate DPPH radical scavenging activity (68.24 %) and the strongest SLO inhibitory activity (83.96 %) at 100 ${\mu}g$/mL. Moreover, HH-2 of four different prescriptions significantly inhibited NO production on LPS-stimulated RAW 264.7 cells in a dose-dependent manner without considerable cell cytotoxicity at range of 2.0 ~ 50 ${\mu}g$/mL. Additionally, HH-2 also effectively suppressed the production of $PGE_2$ and IL-6, which are responsible for promoting the inflammatory process. Major volatile components of HH-2 were identified as eugenol, paeonol, butyl phthalide, ${\beta}$-eudesmol and butylidene dihydrophthalide by GC-MS analysis. Thus, these results suggest that HH-2 may be useful as a potential source of anti-inflammatory agents in herbal medicinal cosmetics.

• Korean Journal of Soil Science and Fertilizer
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• v.29 no.2
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• pp.107-112
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• 1996

To clarify the mechanism of silica adsorption to soil, kinetic study using continuous stirred-flow method was conducted with the Luisiana soil at three pH levels (pH 5.0, 6.5, and 8.0). Silica adsorption increased continuously without showing the maximum adsorption for long enough experimental time. Kinetic curve of silica adsorption could be divided into two stage processes. The first stage process was fitted well to the following equation with highly significant correlation coefficient : $$R_{ad}=K_a*(Q_{OH}^S)^n$$ where, $R_{ad}$ is silica adsorption rate($Si\;{\mu}mal/min$). $Q_{OH}^S$ is the negative charge sites on the soil surface created by alkali titration, and $K_a$ and n are constants. The "n" value of the first stage process was 1.1. This value indicates that the silica adsorption is accomplished by the monodendate ligand bonding. The second stage process was fitted well to the following equation : $$R_{ad}=K_b*(pH)$$ where, $K_b$ is a constant. The equation indicates that the silica adsorption is not proportional to the $OH^-$ ion concentration. Rather, the increasing pattern of silica adsorption rate with the increase of $OH^-$ ion concentration would decrease exponentially.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.171-180
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• 2011

MAI (multiple aperture SAR interferometry) method has been recently developed to improve the measurement accuracy of along-track surface deformation. By means of split-beam SAR processing, this novel technique produces forward- and backward-looking interferograms, which are combined to generate an MAI interferogram. The along-track surface deformation can then be derived from the MAI interferogram. The achieved accuracy of the along-track surface deformation is approximately 8 cm for interferograms with a coherence of 0.6. It is commonly recognized that the topographic phase on an MAI interferogram can be ignored. However, in this paper, we have generated an MAI interferogram from an ALOS P ALSAR interferometric pair spanning the 2010 Haiti earthquake, and shown that the topographic phase distortion on the MAI interferogram can reach to about $3.45{\times}10^{-4}$ rad./m. This distortion corresponds to an along-track surface deformation of about 98 cm. We have proposed an efficient method to remove the topographic phase distortion. After correcting the distortion, the topographic phase distortion on the MAI interferogram is reduced to about $7.82{\times}10^{-6}$ rad./m. This means that the proposed method can effectively remove the topographic distortion on the MAI interferogram to improve along-track surface deformation measurement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3389-3395
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• 2014

Conventional methods, such as the clock time control method and temperature difference control method, for defrost control often encounter mal-defrost and a waste of energy. Therefore, a more efficient method is needed to control defrosting precisely. A photoelectric sensor unit consisting of an emitter and a collector was installed in the front of outdoor heat exchanger. Accurate defrost control was performed by monitoring and using the change in output voltage according to the presence of frost. In this study, experiments were performed to determine if the performance and characteristic curves obtained using the clock time control method can be reproduced using a photoelectric sensor under the heating and defrosting capacity test condition described at KS C 9306. The output voltage of the phototransistor (receiver) and heating capacity, power consumption, and surface temperature of the outdoor heat exchanger, were compared. The results showed that photoelectric sensors can be used as a defrost control method. On-off control timing of the clock time defrosting method was in good agreement with those predicted by the output voltage of the photoelectric sensor.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.4
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• pp.269-279
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• 2002

Housewives residing in the Kyongsang-Buk-do area were surveyed to determine their ownership of Korean traditional kitchen appliances and their usages. A breakdown of the appliances for the survey was as follows: 16 tableware, 17 household utensils, 15 heating utensils, 14 ceramic and earthen pottery, 6 stone utensils, 9 cooking utensils, 9 utensils made of the dried bamboo and bush clover, and 13 dining tables ("sang"). The types of the appliances with the largest ownerships and most frequently used were as follows: The jeopsi was most frequently owned, followed by the daejeop and the jaengban. The most frequently used item was the jubal,, followed by the daejeop and the jeopsi. Among the wooden utensils, bangmangi was most frequently owned, followed by the chanjang, the che, the doe, mal and hop. The most frequently used household utensil was the chanjang, followed by the takjasang and the doe, mal and hop. The utensil the most people owned fur heating was the jujeonja, followed by the seoksoe, the musoesot and the siru. The most frequently used utensil for heating was the jujeonja, the musoesot and the seoksoe, in the order. As for the ceramic and earthen pottery, hangari and dok were owned and used most frequently. The maetdol and the jeolgu, though very low in their ownership rate, were most frequently owned items among the stoned utensils. The kal and the doma were the most frequently owned and used cooking utensils. The sokuri, and the chaeban and the baguni were the most frequently owned among the utensils made of the dried bamboo, bush clover and straw, while the sokuri was used the most frequently, followed by the chaeban and the jori. Among the dining tables, the kyojasang was the item most frequently owned, followed by the seonban and the chaeksangban, while the wonban was the most frequently used, followed by the kyojasang and the chaeksangban.eksangban.