• Journal of the Korean Society of Food Culture
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• v.13 no.3
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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.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.21-28
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• 2018

In recent years, payability of shale gas production has worsened due to oil and gas price declines resulting from sharply increasing shale gas production. Reliable economic evaluation in shale gas development has become important. In this study, Monte Carlo simulation of probabilistic analysis technique was applied to analyze the economic feasibility considering the uncertainty involved in shale gas development. For this, the range of major variables is set and a random number is generated to derive the probability distribution of Net Present Value(NPV) and Internal Rate of Return(IRR). Consequently, we estimated the probability that the feasibility of the project is evaluated to be positive when developing shale gas in the study area. In addition, sensitivity analysis of major parameters affecting economic efficiency in shale gas development was carried out, and the effect of major variables in economic evaluation for commercial production was identified. In the future, this study could be used to make decision for shale gas production by presenting the range of variation of economic index and probability value.

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.5
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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.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.300-307
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• 2009

The transport of landfill leachate in the subsurface formations of unlined landfill sites is considered. The impacts of hydrogeological and chemical heterogeneities on the leachate transport are assessed by examining the results from a series of Monte-Carlo simulations. The landfill system simulated in this study is hypothetically represented with three levels of spatial variability for the hydrogeological and chemical parameter; (1) homogeneous hydraulic conductivity (K) and distribution coefficient ($K_d$), (2) K heterogeneity only, and (3) combined heterogeneities of K and $K_d$. To calculate the transport of leachate through negatively-correlated random hypothetical K-$K_d$ fields generated using geostatistical input parameters, a saturated flow model is linked with a contaminant transport model. Point statistic values such as mean, standard deviation, and coefficient of variation of the concentration were obtained from 100 Monte-Carlo trials. Results of point statistics show that the heterogeneities of K and $K_d$ in the landfill site prove to be an important parameter in controlling leachate concentrations. Consideration of combined K and $K_d$ heterogeneities results in enhancing the variability of contaminant transport. The variability in the leachate concentration for different realizations also increases as the distance between source and monitoring well increase.

• Environmental Analysis Health and Toxicology
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• v.30
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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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• v.15 no.23
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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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• v.47 no.6
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• pp.676-682
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• 2009

Devolatilization of the Refuse Derived Fuel(RDF) which is produced at WonJu in Korea was characterized in air atmosphere with variation of heating rate(10, 20 and $30^{\circ}C/min$) in TGA. The results of TG Analysis have shown that the pyrolysis and char combustion of the RDF occurred in the range of $350{\sim}700^{\circ}C$ depending on the heating rate. Activation energy of the RDF which was determined by using Friedman and Ozawa-Flynn-Wall method was in the range of 14.44~18.40 kcal/mol. Also, reaction order(n) and pre-exponential factors(A) were 1.219 and $3.02{\times}10^5$ by using Friedman method, respectively. In order to find out the devolatilization mechanism of the RDF, twelve solid-state mechanisms defined by Coats Redfern Method were tested. The results of the Coats Redfern Method have shown that chemical reaction is the effective mechanism by comparison with the value of the activation energy which was derived from the Friedman and Flynn-Wall-Ozawa method and correlation coefficient from twelve solid-state mechanisms of Coats Redfern Method. The solid state decomposition mechanism of the RDF was found to be a decelerated $F_1$ type, random nucleation with one nucleus on the individual particle.

• International Journal of Aeronautical and Space Sciences
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• v.8 no.1
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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.

• The Journal of the Korean Society for Microbiology
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• v.35 no.1
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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.

• Journal of Nutrition and Health
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• v.13 no.2
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• pp.82-91
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• 1980

The aim of this study was to define the range of the menstrual blood loss(MBL), and the upper limit of the MBL associated with iron deficiency anemia in Korean women, For this purpose, healthy unmarried women between the age of 15 to 26 years were selected from July to September, 1979 and results obtained were used for determining baseline MBL and its relationship to iron nutriture. One houndred forteen women were tested for their MBL and hematological and biochemical data such as hemoglobin(Hb) concentration, hematocrit, mean corpuscular hemoglobin concentration(MCHC), and serum iron and ferritin concentration. This study was partly supported by World Health Organization. The results of this study are summarized as follows: 1) The mean values and standard error of mean of MBL were $30.7{\pm}2.19ml$ for total subjects, $30.4{\pm}3.14ml$ for sutjects below 20 years of age and $30.3{\pm}2.49ml$ for subjects aged more than 20 years. No significant variation was noted for amount of MBL between two age groups. 2) The median value and 95th percentile value of MBL were 26.5ml and 69.0ml respectively for total subjects. Maximum number (24.6%) of the subjects fell in group with 10-20ml of MBL while 10.5% showed MBL above 50m1. 3) Mean value of the duration of menstruation for total subjects was 4.34 days. 4) It was observed that mean values of Hb concentration, hematocrit and MCHC were decreased slightly in subjects showing MBL more than 40m1. Serum iron and ferritin levels were markedly decreased in women with MBL above 40m1 and 20-30ml, respectively. 5) In subject population showing MBL above 50ml, the frequency of subjects with hematological and biochemical data below anemia criteria were remarkably increased. 6) Although the number of subjects tested was small and the subject selection was not done by random stratified sampling from a population group, this study suggested that the upper normal limit of MBL of Korean women seems to be in the range of 40-50ml.