• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.495-499
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• 2010

To develop chemical and biosensors, this paper studies sensing characteristics of bulk carbon nanotube (CNT) electrodes by means of their electrical impedance properties due to their large surface area and excellence chemical absorptivity. The sensors were fabricated in the form of film and nano web style by using composite process for mass production. The bulk composite electrodes were fabricated with singlewall and multi-wall carbon nanotubes based on host polymers such as Nafion and PAN, using a solution-casting and an electrospinning technique. The resistance and the capacitance of electrodes were measured with LCR meter under the various amounts of buffer solution to study the electrical impedance change properties of them. On the experimental of sensor electrode, impedance characteristics of the composite electrode are affected by its host polymer and nanofiller and its sensing response showed saturated result after applying some amounts of buffer solution for test chemical. Especially, the capacitance values showed drastic changes while the resistance values only changed within few percent range. It is deduced that the ions in the solution penetrated and diffused into the electrodes surface changed the electrical properties of the electrodes much like a doping effect.

• Journal of Preventive Medicine and Public Health
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• v.33 no.2
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• pp.193-198
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• 2000

Objective : To evaluate the relationship between serum leptin concentration and obesity indices in a rural population. Methods : Two hundred and nine subjects were randomly sampled from 1036 residents who had participated in the survey. Their obesity indices were measured by bioelectrical impedance analysis and anthropometry. Serum leptin concentrations were measured by immunoradiometric assay. Results : Serum leptin concentrations were positively correlated with body mass index, percent of body fat, fat mass, waist circumference, and hip circumference. Serum leptin concentrations were higher in obese or overweighted subjects than normal or thin subjects(8.5[0.9-31.4] compared with $2.7[0.1-12.0]{\mu}g/L$, p<0.01). Serum leptin concentrations were higher in women than men, even after an adjustment to body mass index$(\beta=4.183,\;p<0.01)$. According to body composition, serum leptin concentrations were more related with waist circumference in men, hip circumference in women. Conclusions : Serum leptin concentrations are positively correlated with obesity indices. Serum leptin concentrations are higher in obese subjects, in women, and more related with peripheral obesity. These findings support the hypothesis that human obesity is associated with leptin-resistance rather than leptin-deficiency.

• International Journal of Highway Engineering
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• v.10 no.4
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• pp.281-292
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• 2008

In Korea-LTPP(Long Tenn Pavement Performance) project, the full depth asphalt pavement test sections are constructed on the national highway to evaluate the structural capacity of asphalt pavement reinforced with glass fiber. Truck loading test and FWD test were performed to measure the structural capacity of test sections. Test results showed that the reinforcement of glass fiber installed at between surface and intermediate asphalt layer decreased the strain at the bottom of surface layer and moved up the stress neutral axis in asphalt layer. As a result, the tensile stress was developed at the bottom of intermediate asphalt layer of reinforced asphalt pavement, while the compressive stress was developed at the bottom of intermediate asphalt layer of unreinforced asphalt pavement. On the other hand, the tensile strain at the bottom of asphalt base layer didn't show a difference between glass fiber reinforced and unreinforced pavements. From the FWD test, it was shown that the surface deflection of asphalt pavement reinforced with glass fiber decreased 24 percents comparing to that of unreinforced asphalt pavement. This shows that the reinforcement with glass fiber appears to improve the rutting resistance of asphalt pavement.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.336-340
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• 2007

국내 산업 및 기능적 측면에서 중추역할을 수행하고 있는 부산 울산 인천 등 전체 도시의 40%를 이루고 있는 해안도시들이 하천범람과 같은 홍수피해, 해일피해 등에 대한 체계적인 대비가 전무한 실정으로서 본 연구는 모형화 기법을 이용하여 해안도시홍수 경보발령 기준안을 도출하고 이를 실 수문관측 자료를 이용한 검정을 통해 경보발령 기준안의 문제점을 파악하여 그 개선방향을 제시하였다. 대상유역은 대표적 해안도시하천의 특성을 지니고 있는 부산시 온천천유역으로 강우-수위 관측 모니터링 시스템을 구축, 운영을 통해 10분 간격 강우 및 수위 자료를 구축하였으며, 수위 자료는 수위 유량 관계곡선을 이용하여 유량으로 환산하였다. 미계측 상태에서의 수리 수문 모형화를 통해 도출된 경보발령기준안에 대한 평가 및 문제점 도출을 위해 본 연구는 유역내 실시간 수문관측을 통해 얻은 강우 및 유출 특성 자료를 이용하였다. 대상 유역내 경보발령 지점인 세병교 지점의 20분 누가기준 경보발령 기준우량은 한계수위 $H_{c1},\;H_{c2},\;H_{c4}$인 경우 각각 4mm, 5mm, 6mm로서 20개월 동안 이러한 기준을 이용하여 관측된 강우사상 중 경보발령 기준안의 평가가 가능한 26개의 강우사상을 분류할 수 있었다. 그 결과 약 60%의 강우사상(case_1)이 성공한 경보발령 기준우량 임을 관측할 수 있었으며 이러한 발생강우에 대해 $20{\sim}150$분의 대피여유시간을 확보할 수 있었다. 그러나. 경보발령에 실패한 40%의 강우사상은 발생 강우의 총강우량이 대체적으로 적은 경우 및 지속기간 동안 경보발령기준에 준하는 강우를 발생하였으나 수위에 영향이 미비하여 한계수위에 도달하지 못한 경우(case_2), 20분 누가강우는 기준에 도달하지 않았으나 강우 지속시간이 길어 이미 선행강우로 인해 경보발령 이전에 한계수위를 넘어서는 경우(case_3)로서 분석되었다. 이러한 실패한 경보발령의 경우에 대한 원인분석 결과, 기존의 모형화를 통해 고려되지 못하였던 해안도시 홍수의 특성 중 총강우량에 대한 고려, 선행강우 여부 및 강우 지속시간, 지속시간 내 강우집중도 그리고 선정지점 내 조위의 영향과 유역내 합류식 하수관거 시스템의 영향 등 자연유역과는 다른 다소 복잡한 요소를 고려한 해안도시홍수 경보발령 기준에 대한 개선이 필요함을 확인할 수 있었다.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.457-466
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• 1999

원자력 발전소 계측 제어 시스템, 의료 관련 시스템, 항공 관련 시스템 등 실생활과 밀접한 시스템에 소프트웨어의 사용이 점차 증가하고 있다. 이러한 시스템에서 소프트웨어의 오류는 예기치 않는 사고를 유발하여 인명, 재산상의 심각한 타격을 줄 수 있다. 그러므로 고신뢰도 소프트웨어의 개발 시에는 반드시 시스템의 안전성을 보장해 주어야 한다. 역방향 안전성 분석 방법은 시스템의 안전성을 분석하는 한가지 방법으로서 시스템의 위험 상태를 정의하고 그 위험의 원인들을 추적, 분석함으로써 안전성에 대한 효율적인 분석을 수행할 수 있는 장점을 갖는다. 이 논문에서는 소프트웨어 개발 초기 단계에서 안전성을 분석할 수 있는 방법으로 Colored Petri Nets(CPN)에 기반을 둔 역방향 안전성 분석 방법을 제시한다. 또한 CPN 역방향 안전성 분석 도구인 SAC(Safety Analyzer for CPN)의 설계 및 구현에 대해 언급한다. SAC은 기존의 상용 CPN 모델링 도구인 Design/CPN과 연계하여 사용될 수 있으므로 CPN으로 모델링된 시스템의 안전성을 분석할 수 있다는 장점이 있다. 이 논문에서는 예제로 자동 교통 제어 시스템의 일부를 CPN으로 모델링하고 SAC을 이용한 분석 과정을 기술한다.Abstract In safety-critical systems such as nuclear power plants, medical machines, and avionic systems which are closely related with our livings, the usage of software in the controlling part is growing rapidly. Since software errors in safety-critical systems may cause serious accidents leading to financial or human damages, system safety should be ensured during and after development of a system. A backward safety analysis technique defines system hazards and tries to trace their causes by analyzing system states backward. In this paper, we provide a backward safety analysis technique based on Colored Petri Nets(CPN), which is applicable to the early software development phase. Also Safety Analyzer for CPN(SAC), the supporting tool, is designed and implemented. Since SAC is compatible with Design/CPN, a commercial tool for supporting CPN, it can be applicable to analyze safety in practical problems. As an example, we model a part of the traffic light control system using CPN and analyze safety properties of the model using the SAC tool.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.51-60
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• 2011

In this study, structural safety capacity analysis of the overpass railway bridge between Konkuk Univ. and Guui station railroad has been performed. The overpass is expected to have suffered durability reduction by deterioration. The weight reduction of the overpass has been implemented to prevent further durability reduction and to improve performance capacity. To reduce the weight, 3 procedures of replacing concrete soundproofing wall to light-weight soundproofing wall, replacing gravel ballast to concrete ballast, and reducing the weight of trough have been performed. The analysis of static/dynamic behaviors and improved capacity of the light-weighted overpass bridge has been performed. The structural safety verification of the improved structure has been implemented by using rating factors of load carrying capacity of PSC I girder. The results have shown that the deflection has been reduced by 2.6mm and tensile strength has been improved by 1.07MPa, which indicate that the structural capacity has effectively been improved. Also, the natural frequency has improved by approximately 30% where vibration reduction and dynamic behavior improvement have been achieved. Moreover, in the rating factor evaluation based on analysis and test results, an improvement from 1.82 to 1.93 has been observed. Therefore, weight reduction method for the overpass is effective considering overall results.

• Journal of Bio-Environment Control
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• v.10 no.2
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• pp.80-87
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• 2001

This study was conducted to provide basic data for the design of shading facility of greenhouse. The proper distance between external shading screen and roof surface, transmissivity of shading materials, and shading effects of external and internal shadings were analyzed. About a distance of 10 cm between inclined external shading screen and roof surface was enough to guarantee the external shading effect in the greenhouse without roof vent. The inside temperature of greenhouse installed with 85% internal shading screen was lower the maximum of 4$^{\circ}C$ and mean of 2$^{\circ}C$ than that with 55% internal shading screen in both natural ventilation and no ventilation condition. The difference of soil temperature between shading and no shading greenhouse was great, but the difference by shading rate or shading method was small. The performance of external shading for controlling inside temperature down was superior to that of the internal shading. The externally inclined shading screen parallel to the roof surface of greenhouse was more effective than the externally horizontal shading screen in controlling inside temperature of greenhouse without roof vent.

• The Korean Journal of Food And Nutrition
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• v.11 no.2
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• pp.192-199
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• 1998

1. 조사 대상자들의 평균 키와 체중은 각각 161.00$\pm$4.15cm, 50.45$\pm$8.15kg이었으며 BMI는 19.81$\pm$3.98, 체지방율은 26.12$\pm$4.12, skinfold thickness는 40.40$\pm$12.56mm로 나타났다. 2. 조사 대상자들의 혈액성상은 적혈구 수, 헤모글로빈, 헤마토크리트치, albumin, globulin, 총 콜레스테롤, LDL-콜레스테롤, HDL-콜레스테롤, 총 중성지방을 측정하였으며 헤마토크리트치를 제외한 나머지 성상들은 모두 정상 범위에 속하였다. 헤마토크리트치는 정상범주에 미달되는 것으로 나타나 이로 말미암아 철분 결핍성 빈형에 노출될 확률이 아주 많음을 보였다. 3. 용돈별로 체지방율을 분류하여 분석한 결과 한달 용돈이 평균 20~30만원을 쓰는 group의 체지방율이 22.00%로서 정상 수준 이었으며, 30만원 이상 사용하는 group은 비만으로 나타났다.(p<0.05) 한편, 그 외의 group들은 체내 체지방율 수준도 정상 수준인 20~25%를 넘어 체중으로 나타났다. 또한 30만원 이상 사용하는 group은 다른 group보다 RBC(million/㎣), Hb(g/이), Hct(%) 모두가 낮게 나타났으며, 빈혈로 판정될 수 있는 수준이었다. 4. 다이어트 빈도별 각 요인들간의 상관관계를 살펴보면 다이어트 시도를 자주 한다고 답변한 group이 거의 실시하지 않는다., 실시해 본 적이 없다라고 대답한 group보다 체중과 BMI가 유의적으로 낮았다.(p<0.05) 그러나 skinfold thickness(mm)와 체지방율은 유의차가 나타나지 않았다. 따라서 비록 다이어트 실시를 자주할 경우 절대적인 체중감량은 감소되지만 체내 지방량이 감소되는 것은 아니라고 판단된다. 5. 다이어트 실시기간에 따라 혈액 성상을 분석한 결과, 4개월 미만 다이어트를 실시하였으나, 1개월 전부터 현재(설문지에 응답한 시점)까지 기간 중에는 다이어트를 실시한 적이 없다고 대답한 group의 Alb(g/dl)과 Glo(g/dl)의 수치가 다이어트를 실시한 적이 없다고 대답한 group에 비해 유의적으로 높게 나타났다.(p<0.05) 6. 체중은 BMI와 양의 상관관계를 나타내었으며, BMI는 견갑골과도 높은 양의 상관관계를 가졌다. 상완부는 견갑골, skinfold thickness(mm), 체지방율과 높은 양의 상관관계를 보였으며, 반면 Hb(g/dl), Hct(%)와는 음의 상관관계를 나타내었다. 견갑골은 BMI 뿐 아니라 skinfold thickness(mm), 체지방율과 양의 상관관계를 나타내었으며, skinfold thickness(mm)는 체지방율과 유의적인 양의 상관관계가 있음이 나타났다. 7. RBC(million/㎣)는 Hb(g/dl) 및 Hct(%)와 유의적인 양의 상관관계를 나타내었으며, Hb(g/dl)도 Hct(%)와 유의적인 양의 상관관계를 나타내었다. Alb(g/dl)은 Glo(g/dl) 및 TCH(mg/dl), HDL(mg/dl)과도 양의 상관관계를 가졌다. Glo(g/dl)은 TCH(mg/dl)과 양의 상관관계를 보였으며, TCH(mg/dl)은 Alb(g/dl), Glo(g/dl)이에도 TTG(mg/dl), LDL-cho(mg/dl) HDL-cho과도 양의 상관관계를 나타내었다. TTG(mg/dl)은 LDL-cho(mg/dl)과는 양의 상관관계를 HDL-cho(mg/dl)과는 음의 상관관계를 나타내었다.

• Journal of fish pathology
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• v.9 no.2
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• pp.113-118
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• 1996

During a study to document more fully the parasitic ciliates of Korean freshwater fishes, we found numerous small ciliates in the gills and skin of crucian carp, Carassius carassius. Cursory examination indicated that the ciliate were very similar with Chilodonella sp. In this study, we described the morphometrics of this ciliate in detail and compared with other species of Chilodonella in the world. Numerous small ciliates were observed in the body surface, fins and gills of infected fish and excessive mucus production were seen in those fish. Sometimes ulcer was observed in the body of moribund fish. From the scrutinized observation of the parasite, it was identified as Chilodonella hexasticha. The parasite was dorsoventrally flattened body, without a notch in the posterior margin, and it measured 30-$45{\mu}m$ long and 15-$30{\mu}m$ wide. In number of kineties, the right band ciliature was 3-5 and the left band ciliature was 3-5. The right ventral ciliary band shaped arch and was longer than the left, straight band. It had a single oval macronucleus, 8-$15{\mu}m$ in diameter, a single micronucleus, 2-$4{\mu}m$ in diameter. The cytopharynx was reinforced by 10-16 conspicuous nematodesmata, which shaped like a tube and curved at its inner end. Two contractile vacuoles, one anteriorly at right and the second posteriorly at left were observed in wet mounts. This parasite reproduced by a simple division at $22{\pm}1^{\circ}C$.

• Journal of Radiation Protection and Research
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• v.33 no.1
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• pp.35-40
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• 2008

A distillation tower is one of the important facilities which separates and refines a crude oil stream according to certain boiling points. Its operation efficiency can affect the productivity of a refinery substantially. The objective of this study is to elucidate some operational information on the internal conditions of a distillation tower from a measurement of density profile by using a sealed gamma-ray source and a radiation detector. Gamma radiation counts were measured by a BGO detector positioned diametrically outside the tower-wall, opposite to the gamma source(Co-60) as the detector and the source were lowered concurrently. From the results, structural abnormality of the trays was not found inside the tower. Considering the flow distribution patterns, however, a vapor phase was dominantly formed at the upper part of the tower and a liquid phase at the lower part. From the gamma scanning of the distillation tower, it is anticipated that the gamma absorption technique can be used as an important tool for confirming the structural soundness of trays and investigating flow distribution in refinery facilities.