• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.4
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• pp.247-252
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• 1999

In this paper, in order to investigate availability of the OW-PD measurement method which has been proposed as an alternative of AC-PD measurement method to an after laying test and/or diagnosis for the power cable system, partial discharges owing to the needle-type defect integrated into the cable have been measured using AC and OW(Oscillating Wave) voltages. In the AC-PD measurement, the magnitude, phase and pulse number of partial discharges have been changed with the duration of voltage application, which can be analyzed through the relation with the process of the electrical tree initiation and propagation. In addition, the characteristics of partial discharges using OW voltage are appeared to be similar to those in case of AC-PD measurement and to be different with the shapes of electrical tree. From these results, it is concluded that the OW-PD measurement method is available to the tests for the cable system.

• Journal of applied mathematics & informatics
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• v.19 no.1_2
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• pp.397-414
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• 2005

In the existing literature, most of the purchasing models were developed only for retailers problem ignoring the constraint of storage capacity of retailers shop/showroom. In this paper, we have developed a deterministic model of wholesaler-retailers' problem of single product. The storage capacity of wholesaler's warehouse/showroom and retailers' showroom/shop are assumed to be finite. The items are transported from wholesaler's warehouse to retailers' Own Warehouse (OW) in a lot. The customer's demand is assumed to be displayed inventory level dependent. Demands are met from OW and that spaces of OW will immediately be filled by shifting the same amount from the Rented Warehouse (RW) till the RW is empty. The time duration between selling from OW and filling up its space by new ones from RW is negligible. According to relative size of the retailers' existing (own) warehouse capacity and the demand factors, different scenarios are identified. Our objectives are to optimize the cost functions of wholesaler and two retailers separately. To solve this problem, a real coded Genetic Algorithm (GA) with roulette wheel selection/reproduction, whole arithmetic crossover and non-uniform mutation is developed. Finally a numerical example is presented to illustrate the results for different scenarios. To compare the results of GA, Generalised Reduced Gradient Method has been used for the problem. Also, a sensitivity analysis has been performed to study the variations of the optimal average cost with respect to the different parameters.

• Journal of Nutrition and Health
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• v.45 no.2
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• pp.150-158
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• 2012

This study was conducted to investigate the relationship between knowledge of nutrition labeling and the effect on eating habits with 300 high school boys in Seoul. The subjects were divided into an underweight (UW) group (BMI < $18.5kg/m^2$, n = 42), a normal weight (NW) group ($18.5kg/m^2\;{\leq}\;BMI\;<\;23kg/m^2$, n = 129) and an overweight (OW) group (BMI ${\geq}\;23kg/m^2$, n = 79) based on their body mass index (BMI). The average age of participants was 17.8 years old and their mean height and weight were 174.9 cm and 66.5 kg. The mean BMI of subjects was $21.7kg/m^2$ which fell within the normal range. Seventy six point four percent of subjects perceived nutrition labeling and they acquired the information pertaining to it through TV and internet. The UW group and the OW group obtained it from their parents, relatives and friends, while NW group acquired it from school. There were significant differences among groups in the acquired source of the information on nutrition labeling (p < 0.05). The NW group and the OW group trusted nutrition labeling more than the UW group, but there were no significant differences among them. Forty five point five percent of the UW group and 40.7% the NW group were satisfied with nutrition labeling education, while only 15.8% of the OW group did it. The OW group checked nutrition labeling more than the UW group and the NW group at the point of food purchase. The primary reason for examining nutrition labeling was 'to check nutrient contents' in the UW group and the NW group, while the OW group examined it to improve health including regulation of body weight. There were significant differences among groups with regards to the reason for examining nutrition labeling (p < 0.001). The OW group was aware that nutrition labeling affected their eating ha-bits significantly more than the other groups (p < 0.05). Therefore, application-centered education on nutrition labeling and the strong support of the government is needed in order to improve nutrition labeling use and to apply the information from nutrition labeling into student dietary life.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.947-956
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• 2009

Residual petroleum hydrocarbons after an oil spill may accumulate in the marine benthic ecosystem due to their high hydrophobicity. A lot of monitoring data are required for the estimation of ecosystem exposure to residual petrochemicals in an ecological risk assessment in the affected region. To save time and cost, the environmental exposure to them in the affected ecosystem can also be assessed using a simple food-web bioaccumulation model. In this study, we evaluated residual concentrations of four selected polycyclic aromatic hydrocarbons (phenanthrene, anthracene, pyrene, and benzo[a]pyrene) in a hypothetic benthic ecosystem composed of six species under two exposure scenarios. Body-residue concentration ranged 5~250 mg/kg body depending on trophic positions in an extreme scenario in which the aqueous concentrations of PAHs were assumed to be one-tenth of their aqueous solubility. In addition, bioconcentration factors (BCFs) and bioaccumulation factors (BAFs) were evaluated for model species. The logarithm of bioconcentration factor (log BCF) linearly increased with increasing the logarithm of 1-octanol-water partition coefficient (log $K_{OW}$) until log $K_{OW}$ of 7.0, followed by a gradual decrease with further increase in log $K_{OW}$ without metabolic degradation. Biomagnification became significant when log $K_{OW}$ of a pollutant exceeded 5.0 in the model ecosystem, indicating that investigation of food-web structure should be critical to predict biomagnifications in the affected ecosystem because log $K_{OW}$ values of many petrochemicals are higher than 5.0. Although further research is required for better site-specific evaluation of exposure, the model simulation can be used to estimate the level of the ecosystem exposure to residual oil contaminants at the screening level.

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.175-185
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• 2015

Jack-up type WTIV(Wind Turbine Installation Vessel) is used to avoid the effects of waves when installing wind turbines in the Southwest Sea of South Korea. During the preloading procedure, unexpected penetration may cause some risks such as excessive penetration or punch-through failure. To ensure the safety of the WTIV during preloading, the bearing capacities should be evaluated based on the soil data at each borehole. Eight boreholes (OW-1 to -8) have been drilled in the Southwest Sea of South Korea. The bearing capacities of a spudcan designed to be used in this district are calculated using both a conventional analysis and finite element analysis with the soil properties of OW-1 to -8. A finite element analysis is carried out for OW-1, -3, and -4 to gain an in-depth understanding of the soil behavior during the penetration. OW-1, -3, and -4 are representative boreholes for a strong layer overlying a soft layer, a general soft layer, and a soft layer overlying a strong layer, respectively. The resultant bearing capacity curves versus the depth of the numerical analysis are compared with the conventional method. The results show that the conventional analysis is conservative. Case studies for different spudcan areas and shapes are also conducted to seek an appropriate spudcan type for the Southwest Sea of South Korea. Finally, a spudcan with a rectangular shape and a bearing area of $112.8m^2$ is selected.

• Journal of the Korean Society of Food Culture
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• v.18 no.2
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• pp.172-180
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• 2003

This study was performed to document the weight loss diet practice and dietary habit related to weight control in child-bearing Korean women. The subjects were 1,434 women aged 17-39 years. The subjects were classified into 3 groups based on BMI: low weight(LW) BMI < 18.5; normal weight(NW), 18.5 BMI 22.9; and overweight(OW), 23.0 BMI. Anthropometric, general characteristics, weight control practice, and the quality of diet were assessed by a questionnaire. LW group had higher rate of smoking and drinking. They also complained more subjective symptom of anemia and used less nutritional supplementation. Weight loss diet had been practiced by about 40% of subjects and the percent was increased with increasing BMI. The reason of weight loss diet were significantly different by BMI groups(p<0.05); LW to keep body in shape, OW for health. Low BMI group had experienced more side effects after weight loss diet(p<0.05). LW group usually used inappropriate method to control weight such as skipping meals and some of OW group reported using drug to lose weight. All subjects have been skipped their meals of 3.9 times per week, especially 4.3 times in LW group. By mini dietary assessment, most of the subjects did not have regular meals. LW group tended to eat what they like and OW group preferred fried food. This study showed that child-bearing aged women make a ceaseless effort apart from their weight, and LW group have a matter of grave concern because of their dietary habit and weight control practice. Additional research should be necessary to assess the relation of health and weight loss diet in young women.

• Korean Journal of Community Nutrition
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• v.14 no.5
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• pp.483-494
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• 2009

In order to give basic data to teenager's healthcare, we investigated the food habits according to BMI (Body Mass Index), life style, dietary related self-efficacy and food intake through conducting a research surveying 732 middle school students of the Kwang-ju and Chonnam areas. The results of this study were compared groups in under weight (UW), normal weight (NW), and overweight (OW) groups according to BMI levels. In the male students, height was significantly differently in the UW group as $158.2\pm0.7$ cm compared to other NW and OW groups respectively as $163.7\pm0.6$ cm and $162.6\pm0.7$ cm but in the female students there was no significantly difference within groups. Weight was significantly different between the groups in the male students, whereas there were minor differences in the female students. The average of BMI was $20.7\pm0.1$ on the male students and $20.6\pm0.1$ on the female students which were all within the average, and their obesity was increased as the school grade was higher. Under less than 30,000 won of pocket money was dominating, and most of the students were in a nuclear family. In all male and female students, the inactive hours like watching TV and using computers had no differences between groups. The difference between groups was minor on breakfast time and most of the students thought their problems on unbalanced diet. There was significant difference in the OW group in female students as they thought their problems on unbalanced diets. The frequency of snack was significantly low in the OW group of male students but there were no differences in snack and eating-out food. All students chose fruits as snack food and Korean-style food as eating out food. The OW group in male students were significantly low in the dietary related self-efficacy when they were with their families and feeling depressed but there were no differences in female students between groups. When all students were getting higher BMI, they evaluated themselves badly in their self-dietary habits. Also the more male students had non-physical activity time, the less they had the dietary related self-efficacy and the more female students had physical activity time, the higher they had the dietary related self-efficacy. In conclusion, the OW group had good habits in physical activities for weekends, meal times, frequency of snack consumption but it showed undesirable when they were low in dietary related self-efficacy. Therefore we will provide the systematic nutrition education to them through this study.

• The Korean Journal of Food And Nutrition
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• v.30 no.1
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• pp.120-128
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• 2017

This study aimed to provide volatile flavor compounds of three onion products through thermal process and alcohol fermentation, to meet the quality standard of onion products. The identified components of onion extracts (OE) included 49 (18 sulfur-containing compounds, 5 alcohols, 8 acids, 3 ketones, 4 esters, 4 aromatic compounds, 2 aldehydes, 1 pyrazines and 4 miscellaneous compounds), and 55 (17 sulfur-containing compounds, 15 alcohols, 5 acids, 11 ketones, 3 aromatic compounds, 2 aldehydes and 1 pyrazine) in autoclave-sterilized onion extracts (SOE); and 69 (10 sulfur-containing compounds, 27 alcohols, 11 acids, 11 ketones, 6 esters, 1 aromatic compound and 3 pyrazines) in onion wine (OW), respectively. Among the major flavor classes, sulfur-containing compounds (36.8%), acids (31.3%) and aldehydes (13.6%) in OE were changed to alcohols (46.5%) and ketones (27.3%) in SOE whereas, alcohols (56.3%) and acids (26.6%) in OW. Moreover, 1,3-butanediol, 2,3-butanediol, and 3-hydroxy-2-butanone were highly detected in SOE whereas, acetic acid, 3-methylbutanol, 2-phenylethanol and 1,2,3-propanetriol in OW.

• Korean Journal of Community Nutrition
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• v.20 no.6
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• pp.433-446
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• 2015

Objectives: This study was performed to evaluate the consumer education program for reducing sodium intake based on social cognitive theory (SCT) and investigate consumer perceptions of environmental, cognitive and behavioral factors. Methods: Consumers (n=4,439) were recruited nationwide in Korea to participate in a nutrition education program for reducing sodium intake which was targeted on senior housewives (SH), parents (P), and office workers (OW). Questions regarding main factors of SCT were asked both before and after the education program. Results: SH and P recognized external social efforts and information to reduce sodium including nutrition labeling more than OW. The main barriers to practice reducing sodium intake were limited choice of low sodium food and menu, interference with social relationship when dining with others, and limited information, knowledge and skills. SH had lower barriers to practice reducing sodium intake and OW perceived 'preference to soup or stew' and 'preference to Kimchi, salted fish and fermented sauces' as barriers more than other groups at the baseline. Less than 50% of participants knew the relationship between sodium and salt, sodium in nutrition labeling, and recommended sodium intake. In addition, OW had little knowledge for capability to reduce sodium intake and lower self-efficacy to practice compared with SH and P. After education, positive outcome expectations such as lowering blood pressure, prevention of cardiovascular disease and osteoporosis were increased and barriers to practice reducing sodium intake were decreased in all groups (p < 0.05). The knowledge for behavioral capability and self-efficacy to reduce sodium intake were also improved but OW had still lower scores compared with other groups. Conclusions: These results suggested that nutrition education programs could be an effective tool to impact general population by facilitating awareness and increased capability to reduce sodium intake.

• Journal of the Korean Chemical Society
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• v.53 no.3
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• pp.325-334
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• 2009

Many bacteria that are capable to tolerate and degrade organic solvents have been isolated from seawater. However, their roles in the biodegradation of organic solvents in the marine environment have remained unknown. Aeromonas hydrophila IB$B_{ct4}$, isolated from Constanta seawater, was able to tolerate and degrade different organic solvents. Toluene, styrene, xylene isomers, ethylbenzene, with the logarithm of the partition coefficient in octanol-water mixture (log $P_{ow}$) between 2.64 and 3.17, were more toxic for bacterial cells, compared with propylbenzene, n-hexane, n-heptane, with log $P_{ow}$ between 3.69 and 4.39. There were revealed cellular and molecular modifications induced by organic solvents to Aeromonas hydrophila IB$B_{ct4}$. The study of cellular and molecular modifications induced by different organic solvents showed a complex response of bacterial cells to the presence of organic solvents in the culture media.