• 한국작물학회지
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• 제39권2호
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• pp.180-186
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• 1994

콩의 lipoxygenase 활성이 낮은 품종의 육성을 위한 유전육종학적 기초연구의 일환으로 서울대학교 농학과에서 유지해오고 있는 품종 및 계통과 국내 수집계통 등 507점을 공시재료로 하여 lipoxygenase 활성의 변이, 그리고 잡종초기세대를 통한 lipoxygenase 활성의 유전 및 선발효과를 조사한 결과는 다음과 같다. 공시품종 및 계통들의 lipoxygenase 활성은 50~670 unit (unit : $\Delta$0.001/min /mg, 234nm) 의 범위(507품종 및 계통)였으며 평균 350unit로 나타났다. 수집지역과 종실색 구분에 의한 각 그룹별 lipoxygenase 활성의 평균간 차이가 없었으며 성열이 이른 계통의 집단이 lipoxygenase 활성평균이 낮았다. Lipoxygenase 활성은 양적인 유전현상을 나타냈으며 활성을 높게하는 유전자의 상가적 효과가 우성효과보다 큰 것으로 나타났고 활성을 높게하는 유전자와 낮게하는 유전자의 분포비율은 비슷한 것으로 추정되었다. 추정된 협의의 유전력과 광의의 유전력은 0.78($H_n$), 0.86($H_b$)이었고, 선발효율은 고, 저 양 방향으로의 조기세대 선발에 의해 원집단에 비해 높은 방향의 선발에서 29.7~44.7%증가하였고 낮은 방향의 선발에서 21.8~27.3% 저하되었으며 모든 경우에 유의하게 선발효과가 있었다.

• 한국식생활문화학회지
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• 제13권3호
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• pp.169-182
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• 1998

This study was conducted to investigate the consumers' Dining-out preference and behavior for the chilled meat consumption strategy . A total of 328 persons in Seoul, Kyunggi areas were selected by stratified random sampling method and were responded to this study questionnaire which was composed of six parts with 65 statements about chilled meat consumption. 1. The frequency of Dining-out is characterized that 'once a month' is the highest pattern of consumers(46.3%) : In that cases, the married people showed 'once a month'(52.7%) and 'once biweekly'(23.3%), but the unmarried people showed the more frequent pattern as 'once a week'(27.3%) and 'twice a week'(27.3%). And the frequency of Dining-out in relation with the education level revealed that 'the graduate people' are the highest (37.5%). 2. Generally the first food for the Dining-out is 'Kalbi'(26.2%), and the others were 'pork grilling','chilled meat grilling','fish sasimi','chinese foods','pizza' etc.... But there were some variation in relation with incomes and housing types: For the agriculture/physical labor class, they prefers the 'pork griling'(25.0%), the office work class prefers the 'Kalbi' For the house-owner group, they prefers the 'Kalbi', but the house-renting/lodging group, they prefer the 'chinese food' or 'pork grilling' etc.... 3. In choosing the Dining-out place,'quality of food'(54.3%) and 'hygiene'(21.0%) were rated as the first important factor. 4.'Soups', 'Noodles' and 'Cooked rice in casserole' were chosen as good lunch menu : for male, they prefer the 'Soups', but females prefer 'Cooked rice in casserole'. 5. People with commercials/services(44.7%) and agriculture/physical labor(50.0%) ate their lunch in private restaurant, but peoples in the office work(57.0%)/public service personnel(70.4%) and industry use refectory; and it showed significant difference. 6. Consumers prefer the chilled meat as a Dining-out menu, but they didn't recognize the difference between chilled meat and frozen meat 7. For Dining-out menu, many people proper the beef, but the price of beef was so high than pork, agriculture/physical labor class choose the pork grilling instead of beef : commercials/services/office worker prefer the beef chilled meat . 8. The first admirable cooking method for chilled meat is direct radiation grilling with charcoal and many of consumers prefer tender, marbling, some chewy and juicy, flavor, soft as a quality of meat but physical labor class prefer the some tough and chewy texture.

• 한국가스학회지
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• 제22권2호
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• pp.21-28
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• 2018

최근 셰일가스 생산량의 급증에 따른 유 가스 가격 하락이 셰일가스 생산의 채산성 악화를 초래하여 셰일가스 개발 시 신뢰성 있는 경제성 평가가 중요해졌다. 따라서 이 연구에서는 확률론적 분석 기법 중 몬테카를로 시뮬레이션을 적용하여 셰일가스 개발 시 수반되는 불확실성을 고려한 경제성 분석을 수행하고자 하였다. 이를 위해 주요 변수들의 범위를 설정한 후 난수를 발생시켜 순현재가치(Net Present Value, NPV)와 내부수익률(Internal Rate of Return, IRR)의 확률분포를 도출하였고, 연구대상지역에서의 셰일가스 개발 시 사업 타당성이 긍정적으로 판단되는 확률을 추정하였다. 또한 셰일가스 개발 시 경제성에 영향을 미치는 주요 변수에 대한 민감도 분석을 수행하여 상업적인 생산을 위한 경제성 평가 시 주요 변수들의 영향을 파악하였다. 향후 대상지역의 경제성 지표 변동범위와 확률 값을 도출하는 이 연구의 결과는 셰일가스 생산을 위한 의사결정에 활용될 수 있을 것으로 사료된다.

• 한국대기환경학회지
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• 제17권5호
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• pp.425-437
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• 2001

This study is based on the uses meta-analysis methodology to examine the statistical consistency and importance of random variation among results of epidemiologic studies between air pollutants exposure and childhood asthma. Studies for this meta-analysis were conducted by reviewing previous results and by asking researcher active in this field for recommendations. Overall, 10 cases of air pollutants exposures and childhood asthma were reviewed. A variety of statistical methods for meta-analysis have been used to assess the combined effects, to identify heterogeneity, and to provide a single summary risk estimate based on a set of simiar epidemiologic studies. In this study, classification of exposure metircs on air environmental epidemiologic studies are reported for (1) aggravation of childhood asthma by a 50 ppb increase SO$_2$(6 individual studies); (2) aggravation of childhood asthma by a 50 ppb increase NO$_2$(5 individual studies); (3) aggravation of childhood asthma by a 50 ppb increase $O_3$(7 individual studies); (4) aggravation of childhood asthma by a 10$\mu\textrm{g}$/m$^3$increase PM$_{10}$ (4 individual studies); (5) aggravation of childhood asthma by a 1 ppm increase CO (2 individual studies); and (6) comparison of results between a Korean study results and this meta-analytic study. Results of this study indicated that an inverse-variance weighted pooling of the hospital admission risk at a 1ppm increment of CO levels was 1.12% (95% CI : 1.01 ~ 1.24). The hospital admission risk was estimated to increase 5% (95% CI : 1.02~1.08), 6%(95% CI : 1.04~1.09), and 5% (95% CI : 1.02~1.09) with each 50ppb increase of SO$_2$, NO$_2$, and $O_3$, respectively. In addition, our results lead to a small but significant elevation in risk of 2% (RR = 1.02, 95% CI = 1.01~1.04) with each 10$\mu\textrm{g}$/m$^3$increase of PM$_{10}$ among 4 individual studies. We found a small elevation in risk of childhood asthma, and pooled results of 10 epidemiologic studies of childhood asthma using increase a cut-off-point levels of air pollutants showed a few pieces of evidence. The results of this meta-analysis suggested that air pollution associated with an increased incidence of childhood asthma. According to this study, relationship between exposure to air pollutants and childhood asthma in Korea seem to be high than results of this meta-analysis.sis.

• 대한환경공학회지
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• 제31권4호
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• pp.300-307
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• 2009

차수막이 설치되어 있지 않은 매립장에서 하부 지반으로 누출된 침출수의 이동을 고려하였다. 일련의 Monte-Carlo 시뮬레이션의 결과를 검토하여 지반의 수리지질학적, 화학적 불균질성이 침출수 이동에 미치는 영향을 분석하였다. 본 연구에서는 (1) 수리전도도(K)와 분배계수($K_d$)가 균질, (2) 수리전도도만 불균질, (3) 수리전도도와 분배계수가 모두 불균질 경우 등 3단계의 공간 변동성이 있는 가상 매립지 시스템을 시뮬레이션하였다. 포화 유동 모델과 오염물 이동 모델을 이용하여 지구통계학적 입력 인자들로부터 생성된 역상관관계의 랜덤 수리전도도-분배계수 장 내 침출수 이동을 평가하였다. 100회의 Monte-Carlo 시뮬레이션으로부터 얻은 결과에 대하여 평균, 표준편차, 변이계수와 같은 점기반 통계치들을 계산하였다. 통계치 결과에 따르면 매립 지반의 수리전도도와 분배계수의 불균질성은 침출수 농도를 제어하는 주요한 인자로서 수리전도도와 분배계수의 복합 불균질성을 반영함에 따라 오염물 이동의 변동성이 증가하였다. 또한 오염원과 감시정간의 거리가 커질수록 각 실현 간 침출수 농도의 변동성이 증가하였다.

• Environmental Analysis Health and Toxicology
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• 제30권
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• pp.11.1-11.19
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• 2015

Objectives The objective of this study was to conduct a systematic review to provide summarized evidence on the association between maternal exposure to particulate air pollution and birth weight (BW) and preterm birth (PTB) after taking into consideration the potential confounding effect of maternal smoking. Methods We systematically searched all published cohort and case-control studies examining BW and PTB association with particulate matter (PM, less than or equal to $2.5{\mu}m$ and $10.0{\mu}m$ in diameter, $PM_{2.5}$ and $PM_{10}$, respectively) from PubMed and Web of Science, from January 1980 to April 2015. We extracted coefficients for continuous BW and odds ratio (OR) for PTB from each individual study, and meta-analysis was used to combine the coefficient and OR of individual studies. The methodological quality of individual study was assessed using a standard protocol proposed by Downs and Black. Forty-four studies met the inclusion criteria. Results In random effects meta-analyses, BW as a continuous outcome was negatively associated with $10{\mu}g/m^3$ increase in $PM_{10}$ (-10.31 g; 95% confidence interval [CI], -13.57 to -3.13 g; I-squared=0%, p=0.947) and $PM_{2.5}$ (-22.17 g; 95% CI, -37.93 to -6.41 g; Isquared=92.3%, p<0.001) exposure during entire pregnancy, adjusted for maternal smoking. A significantly increased risk of PTB per $10{\mu}g/m^3$ increase in $PM_{10}$ (OR, 1.23; 95% CI, 1.04 to 1.41; I-squared=0%, p=0.977) and $PM_{2.5}$ (OR, 1.14; 95% CI, 1.06 to 1.22; I-squared=92.5%, p<0.001) exposure during entire pregnancy was observed. Effect size of change in BW per $10{\mu}g/m^3$ increase in PM tended to report stronger associations after adjustment for maternal smoking. Conclusions While this systematic review supports an adverse impact of maternal exposure to particulate air pollution on birth outcomes, variation in effects by exposure period and sources of heterogeneity between studies should be further explored.

• Asian Pacific Journal of Cancer Prevention
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• 제15권23호
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• pp.10143-10149
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• 2015

Background and Aim: No firm evidence of HPV infection in esophageal cancer has been established to date. The aim of this meta-analysis was to investigate the prevalence of HPV 16 in esophageal cancer in China, which had a high burden of the disease. Materials and Methods: Studies on HPV infection and esophageal cancer were identified and a random-effects model was used to pool the summary prevalence and corresponding 95% confidence intervals (CIs). Results: A total of 3,429 esophageal cancer cases were evaluated from 26 eligible studies in this meta-analysis. The summary estimate for HPV16 prevalence was 0.381 (95% CI: 0.283, 0.479). The prevalence varied by geographical areas of the study, publication year, HPV detection method and types of specimen. In sensitivity analysis, HPV 16 prevalence ranged from 0.368 (95% CI: 0.276, 0.460) to 0.397 (95% CI: 0.286, 0.508). Conclusions: The results indicate a relatively high level of HPV 16 prevalence in esophageal cancer among Chinese population, although there was variation between different variables. Further studies are needed to elucidate the role of HPV in esophageal carcinogenesis with careful consideration of study design and laboratory detection method, providing more accurate assessment of the HPV status in esophageal cancer.

• Korean Chemical Engineering Research
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• 제47권6호
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• pp.676-682
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• 2009

본 연구에서는 국내 원주에서 생산되고 있는 RDF의 열분해 특성을 조사하기 위해 열중량 분석기(TGA)를 이용하여 비등온 실험(10, 20, $30^{\circ}C/min$)을 수행하여 분석하였다. 다양한 성분의 물질을 함유한 RDF는 승온 속도에 따라 차이가 있으나, 대체로 $350{\sim}700^{\circ}C$ 사이에서 열분해 및 연소되었으며, 최대 열분해 반응속도를 나타내는 온도는 석탄의 그것에 비해 매우 빠름을 알 수 있었다. Friedman 및 Flynn-Wall-Ozawa의 방법을 이용하여 평균한 활성화에너지 값은 각각 14.44, 18.40 kcal/mol이었으며, Friedman의 방법을 통해 반응 차수는 1.219, 빈도인자 $3.02{\times}10^5(s^{-1})$의 값을 얻었다. 또한 Coats Redfern의 방법을 통해 앞서 계산한 활성화에너지 값과의 유사성을 비교하여 고체상의 연소반응 메커니즘을 판단할 경우, 개별 입자들 사이에서 하나의 핵에서 핵화되는 반응인 1차 화학 반응($F_1$)이 가장 유사한 반응 메커니즘으로 판단되었다.

• International Journal of Aeronautical and Space Sciences
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• 제8권1호
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• pp.10-20
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• 2007

For spacecraft attitude control, reaction wheel (RW) steering laws with more than three wheels for three-axis attitude control can be derived by using a control allocation (CA) approach.1-2 The CA technique deals with a problem of distributing a given control demand to available sets of actuators.3-4 There are many references for CA with applications to aerospace systems. For spacecraft, the control torque command for three body-fixed reference frames can be constructed by a combination of multiple wheels, usually four-wheel pyramid sets. Multi-wheel configurations can be exploited to satisfy a body-axis control torque requirement while satisfying objectives such as minimum control energy.1-2 In general, the reaction wheel steering laws determine required torque command for each wheel in the form of matrix pseudo-inverse. In general, the attitude control command is generated in the form of a feedback control. The spacecraft body angular rate measured by gyros is used to estimate angular displacement also.⁵ Combination of the body angular rate and attitude parameters such as quaternion and MRPs(Modified Rodrigues Parameters) is typically used in synthesizing the control command which should be produced by RWs.¹ The attitude sensor signals are usually corrupted by noise; gyros tend to contain errors such as drift and random noise. The attitude determination system can estimate such errors, and provide best true signals for feedback control.⁶ Even if the attitude determination system, for instance, sophisticated algorithm such as the EKF(Extended Kalman Filter) algorithm⁶, can eliminate the errors efficiently, it is quite probable that the control command still contains noise sources. The noise and/or other high frequency components in the control command would cause the wheel speed to change in an undesirable manner. The closed-loop system, governed by the feedback control law, is also directly affected by the noise due to imperfect sensor characteristics. The noise components in the sensor signal should be mitigated so that the control command is isolated from the noise effect. This can be done by adding a filter to the sensor output or preventing rapid change in the control command. Dynamic control allocation(DCA), recently studied by Härkegård, is to distribute the control command in the sense of dynamics⁴: the allocation is made over a certain time interval, not a fixed time instant. The dynamic behavior of the control command is taken into account in the course of distributing the control command. Not only the control command requirement, but also variation of the control command over a sampling interval is included in the performance criterion to be optimized. The result is a control command in the form of a finite difference equation over the given time interval.⁴ It results in a filter dynamics by taking the previous control command into account for the synthesis of current control command. Stability of the proposed dynamic control allocation (CA) approach was proved to ensure the control command is bounded at the steady-state. In this study, we extended the results presented in Ref. 4 by adding a two-step dynamic CA term in deriving the control allocation law. Also, the strict equality constraint, between the virtual and actual control inputs, is relaxed in order to construct control command with a smooth profile. The proposed DCA technique is applied to a spacecraft attitude control problem. The sensor noise and/or irregular signals, which are existent in most of spacecraft attitude sensors, can be handled effectively by the proposed approach.

• 대한미생물학회지
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• 제35권1호
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• pp.19-29
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• 2000

Although most persons infected with Helicobacter pylori harbor a single strain of the organism, multiple strain colonization in the same patient is also occasionally reported in developed countries. The aims of this study were to determine the prevalence of multiple strain colonization in Korean patients and to detect the cagA, iceA1, and babA status of H. pylori isolated from the antrum and body of the stomach. H. pylori was obtained from 35 patients from the antrum and body of the stomach. The genomic diversity of H. pylori was determined by random amplified polymorphic DNA analysis. The status of cagA, iceA1, and babA genes of H. pylori was assessed by polymerase chain reaction with appropriate primers. Clearly different diversity patterns were identified among the isolates from 35 individual patients. Eighteen (51.4%) patients had a single strain of H. pylori. Eight (22.9%) and nine (25.7%) patients had subtypically (one or two bands difference) and typically (clearly different pattern) different strains of H. pylori in the antrum and body, respectively. Among the 70 isolates of H. pylori from 35 patients, the positive rates of 349-bp and 208-bp cagA gene fragments and the iceA1 gene were 68/70 (97.1%), 68/70 (97.1%), and 58/70 (82.9%), respectively. However, the babA gene was found in 22/66 cases (31.4%). In five out of 18 patients with a single strain, the genetic status of cagA, iceA1, and babA varied between the isolates from the antrum and the body. In 8/17 patients with sub typically or typically different strains, the gene status differed between antrum and body isolates. The prevalence of co-colonization with typically or subtypically different strains is high in Korea, and sub-clones with different pathogenic gene status exist within strains of identical RAPD patterns.