• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.628-636
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• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.33-40
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• 2009

In field surveys using the dipole-dipole electrical resistivity method, we often encounter negative apparent resistivity. The term 'negative apparent resistivity' refers to apparent resistivity values with the opposite sign to surrounding data in a pseudosection. Because these negative apparent resistivity values have been regarded as measurement errors, we have discarded the negative apparent resistivity data. Some people have even used negative apparent resistivity data in an inversion process, by taking absolute values of the data. Our field experiments lead us to believe that the main cause for negative apparent resistivity is neither measurement errors nor the influence of self potentials. Furthermore, we also believe that it is not caused by the effects of induced polarization. One possible cause for negative apparent resistivity is the subsurface geological structure. In this study, we provide some numerical examples showing that negative apparent resistivity can arise from geological structures. In numerical examples, we simulate field data using a 3D numerical modelling algorithm, and then extract 2D sections. Our numerical experiments demonstrate that the negative apparent resistivity can be caused by geological structures modelled by U-shaped and crescent-shaped conductive models. Negative apparent resistivity usually occurs when potentials increase with distance from the current electrodes. By plotting the voltage-electrode position curves, we could confirm that when the voltage curves intersect each other, negative apparent resistivity appears. These numerical examples suggest that when we observe negative apparent resistivity in field surveys, we should consider the possibility that the negative apparent resistivity has been caused by geological structure.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.386-392
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• 2013

The purpose of this study was to evaluate the factors related to xerostomia in patients with systemic diseases, and the results were analyzed through t-test, ANOVA, and multiple linear regression analysis. There were 62 respondents (56.9%) who reported dry mouth and the season of the most severe dry mouth was reported to be the highest during winter. According to the analysis made in the relationship of xerostomia with the awareness of general health and health behavior, the group that understood their own health poorly, had more than two kinds of diseases, and had been administered more than two kinds of daily medication showed higher xerostomia. Also, those who experienced desperation, had high dryness in other parts of the body, and heavy snoring were more aware of xerostomia (p<0.05). According to the analysis made in the relationship between xerostomia and awareness of oral health state, the group that understood their oral health poorly and had pain in the oral mucous membrane and halitosis was more aware of xerostomia (p<0.05). According to the analysis made in the relationship between quality of life and xerostomia, the group that showed high level of problem in daily living and stress and were self-conscious and felt tense due to halitosis reported more xerostomia (p<0.05). Finally, xerostomia was most correlated with consciousness of the eyes of others due to halitosis followed by the number of transferred systemic diseases and stress level. Based on such results, xerostomia was understood to be an obstacle in maintaining favorable social life and health. Since xerostomia was shown to be related to the number of transferred systemic diseases, the dental professions are asked to further improve their understanding not only on oral health but also systemic diseases. Therefore, these efforts are expected to prevent xerostomia and reduce various complications caused by xerostomia.

• Journal of dental hygiene science
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• v.13 no.4
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• pp.493-500
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• 2013

The study aims to determine the status of oral health of mental illness patients and establish the preliminary data. The examinations and questionnaire survey were done 92 psychiatric patients to measure sociodemographic characteristics, decayed, missing and filled teeth (DMFT) index, patient hygiene performance (PHP) index, community periodontal index of treatment need (CPITN). Result of the missing teeth index in the state of oral health was higher in the hospital group (6.42) while the filled teeth index was higher in the center group (4.78). In the DMFT index, mental illness patients were higher than the national sample. The oral health status of medical aid recipients was poorer as the subjects were older and less educated (p<0.05). The PHP index was 3.41, close to the bad oral hygiene state. The hospital group (81.7%) required higher need for periodontal treatment. The periodontal health state was much poorer especially when the subject was in the age of 40's and 60's, received less education, and had no family (p<0.05). $CPITN_3$ was higher in the hospital group (13.3%) than the national sample (5.7%). The mental illness patients were socially vulnerable, therefore oral health care program should be needed and age, education level, health insurance type, presence of family and other factors needs to be considered in this approach.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.106-112
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• 2015

This study was conducted to provide with baseline data with the purpose of increasing the values of medical services. Self-administered questionnaire survey was conducted on 236 patients at a dental clinic follow-up visit in dentist clinic Gyeongnam area from June 2013 to August 2013. All statistical analyses were performed using SPSS. The motivation visiting the dental clinic is that the first one is introduction from the family and friends, the second is accessibility, the third is conspicuity and the last one is awareness of the dentist. The main variables in the process of treatment are service system, kindness, satisfaction of service, efficient of re-call system. The relief of discomfort at revisit show the highest score in the process of implant treatment and intention of revisit hereafter do in the prostheses process. In the correlation between main variables, service system and relief of discomfort at revisit (r=0.440, p<0.001), kindness and satisfaction of medical service (r=0.675, p<0.001), revisit hereafter and satisfaction of service (r=0.387, p<0.001) and efficiency of re-call system and revisit showed the highest correlation. The influence on satisfaction of dental service show meaningful level in kindness (p<0.001) and efficiency of re-call system (p<0.05). The intention of revisit is affected meaningfully by relief of uncomfort (p<0.05), service system (p<0.05), kindness (p<0.01) and efficiency of re-call system (p<0.01). In summary, the personal network of patients is most important variable at intention for revisit of dental clinic. As satisfaction of kindness and efficiency of re-call system is higher, satisfaction of medical service and intention for revisit are shown higher. Therefore further research for improvement of satisfaction for medical service and of intention of revisit at the dental clinic should be carried out.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.159-165
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• 2015

A self-administered survey was conducted on the dental hygiene students at three different colleges located in Gyeonggi Province and South Chungcheong Province respectively from October, 2013, to the same month of 2014 to grasp their oral health management behavior, differences in plaque index according to plaque index systems and the correlation of the two. And their plaque index was measured. The findings of the study were as follows: 62.8% of the respondents replied they got a dental checkup over the past year, and 84.1% answered they received preventive dental treatment once at least or more. 80.5% replied they used a fluorine-containing dentifrice. 90.9% answered they used the rolling method to brush their teeth, and 50.0% replied it took three minutes to brush their teeth. They got a mean of 27.88 when O'leary index was used among plaque index systems. Their PHP index and PHP-M index were respectively a mean of 1.30 and a mean of 12.12. Their plaque index became lower when they spent more time brushing their teeth, and the toothbrushing time made a statistically significant difference to that (p<0.05). The factor that exerted the largest influence on plaque index was whether to brush teeth for the sake of oral health (B=-9.747, t=-3.752, p<0.001) or not. That made a statistically significant difference to it. The above-mentioned findings illustrated that more patients visited dental clinics than before to receive preventive dental treatment or to get dental checkups, and that toothbrushing time and whether to brush teeth for the sake of oral health or not were identified as the oral health management behaviors to affect plaque index.

• Journal of dental hygiene science
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• v.15 no.3
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• pp.361-368
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• 2015

The study was conducted to provide data for the development of effective medical conflict prevention programs for dental hygiene by analyzing the dental experience conflicts. A self-administered questionnaire survey was conducted targeting dental hygienists who were performing dental assistance at university hospital, dental hospital and dental clinic in Busan and Gyeongnam regions from April 1 to 30, 2014. Collected questionnaires of 212 dental hygienists were then analyzed with IBM SPSS Statistics ver. 20.0 program. A total of 59.4% had experienced complaints, discontents and medical disputes and 24% of these had experienced a legal trouble developed from such and 95.3% were anxious and doubtful about a possible future medical dispute to some degree. Patient complaints, complaints of non-medical issues raised by 24.3% was the most common, notices, maps and descriptions in relation to the issues raised by 14.4%, is related to the impression issue was raised in the order of 13.5%. Occurrence of disputes did not show a significant difference by place of work, however, a possibility of development of dispute into a legal proceeding showed a significant difference depending on service career and it was investigated that the experienced group feels more pressures with regard to a medical dispute according to their experience of such. All respondents said that education on a prevention and countermeasures of medical disputes is necessary. Understanding of dental hygienists on medical related laws regarding the scope of duty is required to be enhanced and, in order to do so, opportunities to receive an education with regard to a prevention and countermeasures of medical disputes are to be expanded.

• Korean journal of food and cookery science
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• v.29 no.2
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• pp.105-113
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• 2013

Consumer organizations usually lead the opinions of the consumers. This study was performed to investigate the perceptions and information needs of consumer organizations on food additives for the promotion of risk communication. A survey was conducted for 4 weeks in March 2012 by using a self-administered questionnaire consisting of 32 questions. Total 111 responses were collected for analysis. 'Safety (91.0%)' was the most important factor influencing the purchase of processed food, and both 'food additives (24.3%)' and 'environmental pollution (23.4%)' were considered as main risk factors. The longer the career of the members had, the higher negative perceptions on food additives (p<0.01). About 70% of the respondents who had known KFDA's researches on evaluating safety of food additives answered that researches were not enough to make sure the safety. Although lectures and other domestic organization were the main channels for getting information, 'TV' was considered as the most suitable way for it. 'Poor risk communication (32.4%)' was pointed out as the serious problem of government's food safety policy. Based on these results, consumer organizations' low level of trust on government should be overcome by continuous supply of information what they need to facilitate risk communication on food additives.

• Journal of Korea Water Resources Association
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• v.42 no.11
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• pp.911-920
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• 2009

Virtual water is defined as the volume of water required to produce a commodity or service. The degree of food self-sufficiency is currently about 27 % in South Korea, so that Korea is one of the largest net virtual water import countries for agricultural product, thus it is necessary to estimate suitable virtual water for South Korea. The objective of this paper is to quantify the agricultural virtual water use (AWU) and virtual water content (VWC) using the method suggested by Chapagain and Hoekstra during the period 1991-2007. To calculate the virtual water content, 44 different crop production quantity and harvested area data were collected for 17 years and FAO Penman-Monteith equation was adapted for computing crop consumptive use of water. As the results, AWU has been estimated at 15.1 billion $m^3$ in average showing a tendency to decrease. Rice has the largest share in the AWU, consuming about 10.1 billion $m^3$/yr which is about 75 % of gross AWU, and the VWC is 1600.1 $m^3$/ton for paddy rice. The largest VWCs of crops are oilseed and tuber crop, and the smallest are leaf and root vegetables. The primary crop production VWC can be used for calculating the VWC of various secondary products using the contribution ratio, therefore the results of this study are expected to be used as basic data for national agricultural water footprint.

• Journal of Korean Public Health Nursing
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• v.13 no.1
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• pp.97-113
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• 1999

To investigate the actual condition of the adult-smoking in Chinan County. I used self-reporting questionnaires among 923 residents living in nine districts selected at random among the sites of eleven eup-myons from December 28. 1998 to January 6. 1999. collected data and analyized using SPSS. The smoking rate of adults in Chinan County was $36.9\%$. There was a significant difference in smoking rate according to the age. gender, education and job among general characteristics. The smoking rate in group of above 40s was about $40\%$ and that of the male took $55.5\%$ which was higher than that of female and the smoking rate of the people having high-school education was the highest$(46.2\%)$. With regard to the career. the smoking rate of the farmers ranked first$(46.1\%)$. Therefore anti-smoking business for smokers should be focused on above 40 years old, males. people having high school education and farmers. As the result of the survey of smoking habits of 340 people who smoke currently, the average smoking begining age was 21.8 and $81.5\%$ among them was between 16-25 years old. $4.4\%$ was under 15. during around the elementary school. Most motives to smoke were as followed; curiosity or taste$(33.6\%)$, relief of stress $(31.2\%)$, peer presure$(26.5\%)$ And considering the amount of the cigarette which is smoked per day, the case which is less than a pack of cigarettes was highest as $75.5\%$ and the people who smoke over one pack of cigarettes took $24.5\%$. As for the kind of tobacco which is smoked, how to smoke and the desire for the smoking, most case was toxin was moderate$(47.8\%)$ or mild$(46.9\%)$. shallowly$(49.0\%)$ or deeply$(46.3\%)$ and under stress$(33.4\%)$. after meals$(27.8\%)$, during drink$(15.7\%)$ and so on. The highest point marked among the factors of smoking motives was 'the reduce of negative emotion' $(3.27\pm1.00)$. followed by 'uncomfortable habits' $(2.87\pm1.02)$, 'addiction' $(2.84\pm1.06)$. 'habit' $(2.74\pm1.12)$. 'pleasure' $(2.70\pm1.04)$. 'stimulus' $(2.59\pm.90)$, 'sensation-exercise satisfaction' $(2.42\pm.97)$. Smokers smoke to reduce the negative emotions when angry in most common case. depressed. anxious. uncomfortable. lone. ashamed or embarrased. and intend to solve the certain problem. etc. Other motives are uncomfortable habit. addiction. habit. pleasure and the pursuit of stimulus. The level of nicotine dependence of adults m Chinan County was 10.57 which amount to 'high' wholly. As the resulf of the level of nicotine dependence score. the people who are low in the level of nicotine was $33.5\%$. the people who are high was $48.2\%$. very high was $18.4\%$. The approach for anti-smoking for smokers should be conducted differently according to the level of the nicotine. For the people who are in low level of nicotin dependence the prohibition of the smoking should be guided through the approach to foster strong will. for those who are in 'high' by acquiring proper method for the prohibition of smoking. and for those who are 'very high' the anti-smoking should be induced by providing proper program because of the possibility of the suffer from abstinence syndrome. The difference of the level of nicotine with the general characteristics of the objects had not statistically significant difference. The difference of the level of nicotine dependence accompanied by smoking habit had statistically significant difference according to the amount of smoke, the kind of tobacos. smoke inhale habit. In other words, the group of heavy smokers had higher level of the nicotine dependence than that of the light smokers relatively and the group which smoke strong taboaco has higher level of nicotine than that of which smoke mild or moderate. And the group of smokers who smoke deeply has higher level of nicotine than that who smoke shallowly or nonswallow. Aa a result of the analysis of the correlation between smoking motive factors and the level of nicotine, there was the indication that people who smoke for the decrease of the negative emotion. habit, pleasure. stimulus. sensation-exercise satisfaction had high level of the nicotine dependence. As the result of the anti-smoking will of smokers. $65.0\%$ of them had prohibition of smoking will. $29.3\%$ had no will to quit smoke. The most important reason for anti-smoking was health. $67.9\%$ had experience to try to quit smoke and the biggest reason to fail to quit smoking was the lack of the will power to keep anti-smoking. $52.8\%$ of them were advised to stop smoking from their spouses or children. only $2.8\%$ were by medical. The people who have the opinion to need anti-smoking education were $69.6\%$. Therefore when the business for the hygine of the mouth for adult is set. it should be centered on the people who have intention of prohibition of the smoking and help to quit smoking by way of other affirmative counter-program not smoking under stress.