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        검색결과 123

        41.
        2012.04 구독 인증기관 무료, 개인회원 유료
        Based on the Presidential Instruction No. 5 of 2005 concerning the Empowerment of the shipping industries and followed by Shipping Law No. 17/2008, Indonesia has implemented and adopted the cabotage principle.
        4,000원
        42.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        도로표지는 운전자에게 정보제공의 역할을 하는 도로시설물로서 주행경로에 대한 운전자의 판단을 도와준다. 그러나, 주 야간의 온도, 습도 변화로 인한 도로표지판에 결로발생 시, 정보전달의 결함이 발생하여 교통사고 가능성을 높이는 원인으로 작용한다. 따라서, 도로표지판의 결로발생을 예방하기 위한 기술이 필요하다. 본 연구에서는 도로표지판의 결로발생을 예방하는 대안의 효과를 비교하기 위해 단열소재가 삽입된 시편, 결로방지필름이 부착된 시편을 선정하고 결로방지처리가 되지 않은 일반시편과 비교하였다. 분산분석과 사후검정(Tukey HSD)을 통해 각 시편에 발생한 측정시간에 따른 결로량을 비교 했으며, 결로량과 재귀반사도의 관계를 Pearson의 상관분석으로써 검증하였다. 분석결과, 결로방지필름이 부착된 시편에서 결로량이 적게 나타났으며, 결로발생 90초 후에는 결로방지필름의 부착 시편과 단열소재가 삽입된 시편에서 나타나는 결로량은 결로방지 처리가 되지 않은 시편에서 발생한 결로량과의 통계적인 차이가 존재하였다. 또한, 상관분석결과로써 결로량과 재귀반사도는 반비례하는 것으로 나타났다. 따라서, 도로표지판에 발생된 결로량과 재귀반사 변화율에 대하여, 결로방지필름의 부착과 단열소재의 삽입은 결로방지에 효과가 존재하는 것으로 판단된다.
        4,000원
        43.
        2012.03 구독 인증기관 무료, 개인회원 유료
        DNA methyltransferase 1 (Dnmt1) gene contains three different isoform transcripts, Dnmt1s, Dnmt1o, and Dnmt1p, are produced by alternative usage of multiple first exons. Dnmt1o is specific to oocytes and preimplantation embryos, whereas Dnmt1s is expressed in somatic cells. Here we determined that porcine Dnmt1o gene had differentially methylated regions (DMRs) in 5’-flanking region, while those were not found in the Dnmt1s promoter region. The methylation patterns of the porcine Dnmt1o/Dnmt1s DMRs were investigated using bisulfite sequencing and pyrosequencing analysis through all preimplantation stages from one cell to blastocyst stage in in vivo or somatic cell nuclear transfer (SCNT). The Dnmt1o DMRs contained 8 CpG sites, which located in —640 bp to —30 bp upstream region from transcription start site of the Dnmt1o gene. The methylation status of 5 CpGs within the Dnmt1o DMRs were distinctively different at each stage from one-cell to blastocyst stage in the in vivo or SCNT, respectively. 55.62% methylation degree of the Dnmt1o DMRs in the in vivo was increased up to 84.38% in the SCNT embryo, moreover, de novo methylation and demethylation occurred during development of porcine embryos from the one-cell stage to the blastocyst stage. However, the DNA methylation states at CpG sites in the Dnmt1s promoter regions were hypomethylated, and dramatically not changed through one-cell to blastocyst stage in the in vivo or SCNT embryos. In the present study, we demonstrated that the DMRs in the promoter region of the porcine Dnmt1o was well conserved, contributing to establishment and maintenance of genome-wide patterns of DNA methylation in early embryonic development.
        4,000원
        44.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We investigated the effect of glutathione supplementation on feed intake, body weight loss, behavior change and economic analysis of elk bull in breeding season. Sixteen elk bulls (5-year-old, average weight; 330 kg) after antler cutting were divided into 2 groups. Eight bulls in each group (control and glutathione group) were fed experimental diet at a level of 0.85 percent of body weight and 6 mg glutathione per kg body weight. As a result, weight-loss of control animal during experimental study (from September to November) was 42.6±19.2 kg while that of glutathione-supplemented group was 20.6 ±19.9 kg. Compared to control group, glutathione-fed group had prevented the body weight loss by 5.2% (p<0.05). Although the feed intake of elk voluntarily decreases during breeding season, daily DM intake per head was 5.59 and 5.80kg in control and glutathione-fed group, respectively. While the statistical difference in feed intake between two groups was not observed, feed intake tended to increase in glutathione-fed group. In economic analysis, additional cost of 99,000 KRW per head was spent due to the cost of glutathione because of its import. Changes in behavior such as crying, deer whistles, whistling intensity and frequency of accident were lower in glutathione-fed group compared to control. During breeding season, use of glutathione as feed supplement could suppress body weight loss and accidents in deer farm.
        4,000원
        45.
        2011.09 구독 인증기관 무료, 개인회원 유료
        In the present study, we identified differentially methylated region (DMR) upstream of Dnmt1o and Dnmt1s gene in early porcine embryos. Porcine Dnmt1o had at least one DMR which was located between —530 bp to —30 bp upstream from transcription start site of the Dnmt1o gene. DNA methylation analyses of Dnmt1o revealed the DMR to be hypomethylated in oocytes, whereas it was highly methylated in sperm. Moreover, the DMR upstream of Dnmt1o was gradually hypermethylated from oocytes to two cells and dramatically changed in the methylation pattern from four cells to BL stages in an in vivo. In an IVF, the methylation status in the DMR upstream of Dnmt1o was hypermethylated from one cell to eight cells, but demethylated at the Morula and BL stages, indicating that the DNA methylation pattern in the Dnmt1o upstream ultimately changed from stage to stage before the implantation. Next, to elucidate whether DNA methylation status of Dnmt1s upstream is stage-by-stage changed in during porcine early development, we analyzed the dynamics of the DNA methylation status of the Dnmt1s locus in germ cell, or one cell to BL cells. The Dnmt1s upstream was highly methylated in one and eight cells, while less methylated in two, four, morula, and BL cells. Taken together, our data demonstrated that DNA methylation and demethylation events in upstream of Dnmt1o/Dnmt1s during early porcine embryos dramatically occurred, and this change may contribute to the maintenance of genomewide DNA methylation in early embryonic development.
        4,000원
        47.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        도로기하구조정보는 도로의 안전성평가 및 도로의 유지관리를 위한 필수적인 요소이다. 본 연구에서는 GPS(Global Positioning System)/INS(Inertial Navigation System)센서가 탑재된 조사차량을 이용하여 기하구조정보를 수집하였으며, 수집된 차량의 자세정보 중 평면선형과 관련된 Roll, Heading 자료를 이용하여 직선, 원곡선, 완화곡선을 구분하는 알고리즘을 개발하였다. 본 연구에서는 평면선형 인식 이전에 전처리 과정으로 이동평균법을 통하여 자료를 평활화함으로써 원시자료의 이상치를 제거하여 평면선형 인식의 신뢰성을 제고하였다. 유전알고리즘(GA, Genetic Algorithm)을 이용하여 분류정확도(CCR, Correct Classification Rate)를 최대로 하는 알고리즘 파라미터를 설정한 결과 100%의 분류정확도를 보였다. 설정된 파라미터를 이용하여 고속도로와 국도 주행자료를 이용하여 알고리즘을 평가한 결과 90.48%와 88.24%의 분류정확도를 보여, 제안된 평면선형인식 알고리즘은 현장에서 적용 시 높은 신뢰도를 가지는 정보를 제공 가능한 것으로 분석되었다. 본 연구에서 개발한 평면선형인식 알고리즘은 조사차량에 GPS/INS센서의 소프트웨어로 탑재되어 도로 및 교통기술자에게 도로기하구조정보를 보다 용이하게 수집하고 분석할 수 있는 환경을 제공하는데 기여할 것으로 기대된다.
        4,200원
        48.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        교통사고 원인분석 및 사고예방을 위해서는 교통사고 유발요인에 대한 이해가 필요하다. 기존 연구에서는 기하구조, 운전자 특성 등의 요인을 고려하여 연구를 진행하였다. 그러나, 운전자 특성요인 분석에 사용된 자료는 검지기에서 측정된 집계된 속도로써, 속도 변화량을 이용한 사고분석연구에는 한계가 존재한다. 따라서, 본 연구에서는 차량의 속도변화 등의 수집이 용이한 센서를 이용하여 자료를 수집하였다. 가속도자료 및 기하구조 특성을 나타내는 변수를 설정하고, 사고자료와 매칭을 통해 사고개연성이 높은 잠재적 변수로의 적합성을 평가하였다. T-test, 이항 로지스틱 회귀분석을 사용했으며, T-test 결과로써 도출된 변수를 이항 로지스틱 회귀분석의 독립변수에 적용하고, 사고발생 유 무를 종속변수로 설정하였다. 분석결과, 5개의 변수가 사고발생에 영향을 주는 변수로 도출되었다. 또한, 도출된 모형은 사고발생구간의 예측에 적용할 수 있는 타당성을 확보하는 것으로 분석되었다. 본 연구에서 도출된 위험 운전행태 변수 및 모형은 프로브차량에 설치하여 활용할 수 있는 장치 등에 적용시켜 사고위험도 및 안전성 평가에 활용할 수 있을 것으로 기대된다.
        4,000원
        49.
        2011.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In this study, an enthalpy exchanger was coated by silver nano particles via spark discharge method and its antimicrobial and heat exchange efficiencies were evaluated. A method utilizing thermophoretic force was used to improve coating efficiency. Four spark discharge systems were parallel connected and generated silver nano aerosol particles (number concentration of 1.65×108 particles/cc, mode diameter of 31 nm). The coating efficiency was evaluated according to various face velocities (V=0.25~1 m/s) and temperature gradients ((Thot-Tcold)/Thot=0~0.09). The maximum coating efficiency was 90.8 % when the face velocity was 0.25 m/s and the temperature gradient was 0.09 (Thot=30℃, Tcold=2℃). Silver nano particles were coated onto the enthalpy exchange element and two different coating amounts of silver nano particles (0.11 ㎍/cm3 , 0.22 ㎍/cm3 ) were tested. For evaluation of antimicrobial efficiency, the suspension test method with E. coli was used. After the suspension test method, CFU(colony forming unit)s of each test sample were counted and colony ratio was calculated. The colony ratio was decreased more quickly when the amount of coated silver particles was increased. When the contact time between each sample and suspension was over 3 hours, antimicrobial efficiencies of coated samples were more over 99.9 % for both amount of silver nano particle(0.11 ㎍/cm3 , 0.22 ㎍/cm3 ). The coating of silver nano particles did not affect the heat exchange efficiency.
        4,600원
        50.
        2010.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Bioaerosols, airborne particles of biological origin, are omnipresent in the common surroundings of humans. In antimicrobial filter system, as particles or organic materials are deposited on the filter surface, the bacteria come into contact with the antimicrobial material less, and thus they can easily grow on particles or organic materials. We selected a carbon fiber ionizer which generated air ions as antimicrobial agent. Antimicrobial effect of carbon fiber ionizer on the outlet air and condensate water was tested using application of carbon fiber ionizer in a small-scale commercial air conditioner. In conclusion, the application of carbon fiber ionizer in the air conditioner showed more increasing antimicrobial efficiency.
        4,300원
        52.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        시선유도시설은 주 야간에 도로의 직선 및 곡선구간 선형에 관한 정보를 운전자에게 제공하고 차선의 역할을 수행하는 시설물이다. 특히, 시선유도표지(델리네이터)는 도로 선형에 관한 정보를 제공하고 차량이탈사고 예방등에 활용되는 대표적인 시선유도시설이다. 본 연구에서는 시선유도표지(델리네이터)의 설치지침에 제시한 기준을 피실험자의 만족도를 통해 평가하고 델리네이터의 높이와 크기가 고려된 델리네이터 간격을 설정하는 방법론을 제시하였다. 실험결과, 델리네이터의 간격과 크기에 대한 피실험자의 만족도는 낮게 나타났으며, 델리네이터의 높이에 대한 피실험자의 만족도는 높게 나타났다. 또한, 본 연구에서는 독립변수를 델리네이터의 간격, 높이 및 크기로 설정하고 종속변수를 이용자 만족도로 사용하여 이항 로지스틱 회귀분석을 실시하였다. 분석결과를 통해 이용자의 73%가 만족하고 델리네이터의 높이와 크기가 고려된 델리네이터 간격을 설정하여 제시하였다. 델리네이터 크기가 100mm인 경우 높이에 따라 6.10~14.28m의 간격을 선정해야하며, 델리네이터 크기가 150mm인 경우 높이에 따라 22.01m~30.19m의 간격을 설정해야 하는 것으로 분석되었다.
        4,000원
        53.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 2003년에서 2005년도까지 통계청에서 조사한 농산물 생산비 통계와 농가경제통계의 원자료를 이용하여 마늘 생산농가의 기술적 효율성과 그 결정요인을 분석하는데 있다. 분석은 패널자료를 이용하여 기술적 비효율성 효과모형과 확률적 프론티어 생산함수 모형을 이용하여 수행되었다. 2003년에서 2005년 까지 전국적으로 마늘 생산농가의 평균적인 기술적 효율성은 0.772로 추정되었다. 이것은 마늘 생산에 있어 22.8%의 기술적 비효율이 존재하는 것을 의미한다. 이를 바탕으로 마늘 생산농가의 기술적 효율성을 제고할 수 있는 정책대안을 제시하였다.
        4,000원
        54.
        2008.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Characteristics of commercial antimicrobial filter media for bioaerosol removal were estimated. A chitoasn/ medium filter, a catechin/HEPA filter, a silver/HEPA filter, a copper/pre filter, a electret cabin filter and a non-electret cabin filter were used for estimation. Filtration efficiency and antimicrobial efficiency was tested using Escherichia coli and Staphylococcus epidermidis. The electret cabin filter and the chitosan/medium filter showed the highest filtration and antimicrobial efficiency, respectively.
        4,000원
        57.
        2006.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Bioaerosols are airborne particles of biological origins including viruses, bacteria, fungi, and all varieties of living materials. In suitable hosts, bioaerosols are capable of causing acute or chornic diseases that may be infectious, allergenic, or toxigenic. Bioaerosols from outdoor air accumulate on filters of heating, ventilating and air conditioning (HVAC) system in large quantities and are able to multiply there under certain conditions. In this study, silver was coated on activated carbon fiber (ACF) filters by an electroless plating method, and their efficacy for bioaerosols removal was tested. Physical filtration and biological antimicrobial test were performed. SEM and XRD analyses were used to characterize the morphology and components of ACF filters. Electroless silver-plated ACF filters showed antimicrobial efficiency, whereas pure ACF filters did not. It was found that electroless silver plating did not influence the physical filtration efficiency of ACF filters.
        4,000원
        58.
        2005.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        A ventilation system comprising a dielectric barrier discharger and UV‐TiO2 photocatalyst filters was designed and tested for simultaneous removal of gaseous and particulate contaminants in a test chamber. The DBD was used as the 1st stage of ESP for particle charging and gas decomposition. Charged particles were collected in the 2nd stage of ESP by an applied DC electric field. The UV‐TiO2 photocatalyst filters were used for decomposing gaseous species including O3 which was inherently produced by the DBD. Particle removal efficiencies based on mass and number were approximately 83.0% and 88.8%, respectively, after the ventilation system was operating for 5 hours. HCHO removal efficiency was approximately 100% for 1∼5ppm of upstream concentration condition. TVOC removal efficiency was 99.0% and 99.6% for 1 ppm and 5 ppm of upstream concentration conditions, respectively.
        4,200원
        59.
        2004.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Abstract Dielectric barrier discharge (DBD) in air, which has been established for the production of large quantities of ozone, is more recently being applied to a wider range of aftertreatment processes for HAPs (hazardous air pollutants). Although DBD has high electron density and energy, its potential use as precharging nano and submicron sized particles, is not known. In this work, we measured V‐I (voltage‐current) characteristics of DBD and estimated the collection efficiency of particles with bimodal distribution by DBD type 2‐stage ESP (electrostatic precipitator). To examine the particle collection with various applied voltage waveforms of DBD, nano size particles of NaCl (20∼100 nm) and DOS (50∼800 nm) were generated by an electrical tube furnace and an atomizer, respectively. Particle collection efficiencies of all the cases increased with increase of DBD electric power that the results corresponded to product of V by I whose magnitudes were the largest in triangular voltage waveform.
        4,200원
        60.
        2004.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Decomposition of ozone at room temperature was investigated by comparing between commercial monolithic ozone decomposition catalyst (ODC, MnO2) filter and monolithic photocatalyst (TiO2) filter. The effects of residence time, UV (ultraviolet, A type) irradiation, and upstream ozone concentration on the ozone conversion were discussed. UV ray was irradiated using four BLB (black light blue) lamps (λ: 310∼ 400nm) of constant intensity. The upstream concentration of ozone was controlled by an electrostatic ozone generator. For ODC performance, the presence of UV irradiation slightly affected initial ozone conversion compared with no UV irradiation condition. However, for photocatalyst, the ozone was highly decomposed in the presence of UV irradiation. Long time performances of the both catalysts were evaluated by a real-time ozone monitoring system during 120 hours. The results show that the UV irradiation enhanced the ozone conversion for the both catalysts.
        4,300원
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