• Journal of the Korean Geotechnical Society
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• v.26 no.12
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• pp.19-30
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• 2010

Bentonite-based grout has been widely used to seal a borehole constructed for a closed-loop vertical ground heat exchanger in a geothermal heat pump system (GHP) because of its high swelling potential and low hydraulic conductivity. Three types of bentonites were compared one another in terms of viscosity and thermal conductivity in this paper. The viscosity and thermal conductivity of the grouts with bentonite contents of 5%, 10%, 15%, 20% and 25% by weight were examined to take into account a variable water content of bentonite grout depending on field conditions. To evaluate the effect of salinity (i.e., concentration of NaCl : 0.1M, 0.25M, and 0.5M) on swelling potential of the bentonite-based grouts, a series of volume reduction tests were performed. In addition, if the viscosity of bentonite-water mixture is relatively low, particle segregation can occur. To examine the segregation phenomenon, the degree of segregation has been evaluated for the bentonite grouts especially in case of relatively low viscosity. From the experimental results, it is found that (1) the viscosity of the bentonite mixture increased with time and/or with increasing the mixing ratio. However, the thermal conductivity of the bentonite mixture did not increase with time but increased with increasing the mixing ratio; (2) If bentonite grout has a relatively high swelling index, the volume reduction ratio in the saline condition will be low; (3) The additive, such as a silica sand, can settle down on the bottom of the borehole if the bentonite has a very low viscosity. Consequently, the thermal conductivity of the upper portion of the ground heat exchanger will be much smaller than that of the lower portion.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.187-196
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• 1982

The followings are the results of the study on industrial accidents occurred at 12 factories manufacturing metal products during the period of 2 years from January 1980 to December 1981 in the area of Yong-Dung-Po in Seoul. The results of the study are as follows: 1. The incidence rate of industrial injuries was 45.7 per 1,000 workers of the sample group and the rate of male (54.0) was three times higher than that of female (17.5). 2. In age groups, the highest rate was observed in the group of under 19 years old with 83.5, while the lowest in the group of 40s. 3. It was found that those who had short term of work experience produced a higher rate of injuries, particularly, the group of workers with less than 1 year of experience showed the highest rate of it as 48.1%. 4. In working time, the highest incidence rate occurred 3 and 7 hours after the beginning of their working showing the rate of 6.0 and 6.1 per 1,000 workers, respectively. 5. The highest incidence rate was observed on Monday as 8.4 per 1,000 workers, and it was 18.3% in aspect of the days of a week. 6. In aspect of the months of a year, the highest incidence was observed on July 1,000 workers and the next was on March as 4.8. These figures account for 11.8% of total occurrence in respective month. as 5. 4 per and 10.5% 7. In causes of injuries, the accident caused by power driven machinery showed the highest rate with 37.5%, the second was due to handling without machinery with 17.2%, and the third was due to falling objects with 14.2%, and striking against objects with 10.2%, and so on. 8. By parts of the body affected, the most injuries 84.3% of them occurred on both upper and lower extremities with the rate of 58.8% for the former and 25.5% for the latter. Fingers were most frequently injured with a rate of 40.3%. Comparing the sites of extremities affected, rate of injuries on the right side was 55.0% and 45.0% on the left side. 9. In the nature of injury, laceration and open wound were the highest with 34. 0%, the next was fracture and dislocation with 31. 9%, and sprain was the third with 8.1%. 10. On the duration of treatment, it lasted less than one month in 68.9% of the injured cases, of which 14.5% of the cases were recovered within 2 weeks, and 54.4% of them were treated more than 2 weeks. And the duration of the treatment tended to be prolonged in larger industries. 11. The ratio of insured accidents to uninsured accidents was 1 to 4.7.

• Korean journal of communication and information
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• v.44
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• pp.76-107
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• 2008

The present study has explored the effects of media use on the evaluation of the presidential candidate's morality. We hypothesized that the perception of the candidates' morality during the 2007 Korean President Election would be influenced by the amount of the different types of media use. Using a set of panel data, a total of 1,199 citizens (584 females (48.7%), 615 males (51.3%), Mage=42.77, SDage=13.34) were assessed four times from August to December in 2007. The results indicated that (a) the level of TV use for political information, the level of newspaper use for political information, and the level of Internet use for political information increased during the five months; (b) the initial level of political involvement contributed differently to the initial levels of media use; (c) the initial level of political involvement negative influenced the initial level of TV use for political information; (d) the growth of political involvement positively influenced the growth of TV use for political information; (e) the intial level of TV use for political information increased both the initial levels of the perception of candidates' morality and the change of the perception of candidates' morality; (f) the change of TV use for political information negatively affected the perception of candidates' morality; and (g) the initial level of Internet use for political information negatively affected the initial level of the perception of candidates' morality, and the change of Internet use for political information negatively affected the perception of candidates' morality.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.2
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• pp.106-115
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• 2011

The aim of this study is to assess the importance of ballast water discharge as a vector for the introduction of exotic species into Pusan and Daesan Ports, Korea. We also examined to understand the impacts of environmental factors on the survival success of introduced species by ship's ballast water in laboratory experiments. Seven ship's ballast water originated from the coastal water of China (Taicang, Ningbo and Jinshan), Japan (Tokuyama, Moji and Akita), and Singapore. According to PCA (principal components analysis) analysis, environmental factor in the each ballast and shipside waters were different by bioregion. Based on cluster analysis, the phytoplankton community structures were distinguished for ballast water origin. Most of the major taxonomic groups were diatoms and, the others were dinoflagellate, silcoflagellate and several fresh-waters species. In particular, species number and standing crops of phytoplankton in the ballast tanks decreased with the increasing age ofballast water(r = -0.35 for standing crop; r = -0.63 for species number). In the laboratory study, although phytoplankton in ballast water treatment did not survive even in optimal temperature, the in vivo fluorescence of phytoplankton viability increased under the nutrient typical of shipside water and F/2 medium at $15^{\circ}C$ and $20^{\circ}C$. The diatoms species such as Skeletonema costatum and Thalassiosira pseudonana in ballast water were successfully regrown. On the salinity gradient experiments for Shui Shan (2) vessel, several freshwater species, brackish and marine species were successfully adapted. Of these, S.costatum was able to tolerate a wide range of salinities (10 to 30 psu) and its species-specific viability was suitable for colonization.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.2
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• pp.357-367
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• 2018

Recent earthquakes in Gyeongju and Pohang have raised interest in liquefaction in South Korea. Liquefaction, which is a phenomenon that excessive pore pressure is generated and the shear strength of soil is decreased by repeated loads such as earthquakes, causes severe problems such as ground subsidence and overturning of structures. Therefore, it is necessary to identify and prepare for the possibility of liquefaction in advance. In general, the possibility of liquefaction is quantitatively assessed using the Liquefaction Potential Index (LPI), but it takes a lot of time and effort for performing site response analysis which is essential for the liquefaction evaluation. In this study, a simple method to evaluate the liquefaction potential without executing the site response analysis in a downtown area with a lot of borehole data was proposed. In this simple method, the correlation between the average shear wave velocity of the target location ground and the LPI divided by thickness of liquefiable layer was established. And the applicable correlation equation for various rock outcrop accelerations were derived. Using the 104 boreholes information in Seoul, the correlation equation between LPI and the shear wave velocity (ground water level: 0m, 1m, 2m, 3m) is obtained and the possibility of liquefaction occurrence in Seoul and Gyeongju is evaluated. The applicability of the proposed simple method was verified by comparing the LPI values calculated from the correlation equation and the LPI values derived using the existing site response analysis. Finally, the distribution map of LPI calculated from the correlation was drawn using Kriging, a geostatistical technique.

• Journal of the Korean Society of Food Culture
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• v.13 no.4
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• pp.267-274
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• 1998

The consumption patterns of the minimally processed fruits and vegetables were surveyed in this present study. Eighty four women who were resident in either Seoul and Kyongki-do in Korea were participants in this study as respondents to our various questionnaire. The result are summarized as follows; The respondents had a preference for a supermarket (46.4%) as the place of purchase (or fruits and vegetables and the frequency of purchase was two or three times per week. The residents of apartment preferred department stores and supermarkets to stalls in the immediate residential area (p<.05). Fifty percents of the unmarried women respondents indicated that they only purchased once a week. Approximately 70% of the respondents rated quality considerations over the price and quantity when they choose their fruits and vegetables. This behavioral tendency was stronger for the residents of the apartment and amongst the more highly educated women. The type of fruits and vegetables purchased were mainly unprocessed. However, minimally processed products appeared to be popular especially among unmarried or married who did not have children, were highly educated and aged between 20 and 30. These observations are supported by data in which 82% of respondents whose ages were ranged between 20 and 30, with high educational backgrounds and who had experienced in the purchase of minimally processed fruits and vegetables. The motivation for purchasing minimally processed fruits and vegetables generally resulted from a consideration of the saving in cooking time, the ease of handling and the desire to serve appropriate portions. On the other hand, the reasons for not purchasing minimally processed fruits and vegetables were the comparatively high price, a perception of unsanitary handling and pack size that were considered too small. Ninety-three percent of the respondents exhibited a positive response to the need for minimally processed fruits and vegetables. Freshness was considered to be the most important factor when purchasing these products. The preferred price for the minimally processed fruits and vegetables was approximately $110{\sim}120%$ of that for the unprocessed products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.8
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• pp.3547-3554
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• 2011

The aim of this study is to take hold of the present situation as well as the perspective of the domestic alcohol specialized hospitals. The structured questionnaire was prepared to understand the type of services, manpower and systematic programs. Among eight hospitals that stand for the alcohol addiction specialized hospitals, six hospitals agreed to participate in the survey, which was made from Jun. 17 to July 15, 2010. The average number of beds of the surveyed hospitals was 208. They were mostly private ones(66.7%), located in urban area(50%), and had experiences of alcohol treatment less than five years(50%). While all of them practiced both the inpatient and outpatient services, only 33% provided the systematic outpatient program that was at least 2 or 3 hours per week. All hospitals practiced the physical and individual psychological evaluations, but only 16.1% had the daytime programs. The beds of protective ward were 72% of all beds, and the beds of night and day occupied 7.6% and 2.6% respectively. It was found that although the average number of mental health social worker and mental health nurse was larger than that required in the regulation of mental health law there are significant deviations between hospitals. However, the manpower of psychiatrists and nurses were comparatively large. The first problem indicated by clinical experts was the patient's refusal of care, which results in an inefficiency in the treatment. The next problem was the lack of local health care institutions that can attend on the discharged patients were important issues. Also the low reimbursement and indifferences to the alcohol abuse were considered as important issues.

• The Journal of Korean Physical Therapy
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• v.3 no.1
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• pp.109-121
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• 1991

To investigate the period prevalence rate and therapeutic practic for low back pain (LBP) in the adult population of rural area, a personal interview was conducted for 2.024 persons or 20-59 years old in Seohu Myon, Andong County, Kyungpook Province between 1st and 20th of April, 1991. The period prevalence rate (l February 1990-31 January 1991) of LBP for 1,106 adults who were interviewed was $47.9\%$. The age adjusted period prevalence rate for males was $43.7\%$ and that for females was $52.3\%$ and the difference was statistically significant (p<0.005). Clinical course of th LBP was acute in $14.1\%$ of males and $9.0\%$ of females, recurrent in $57.0\%$ and $55.2\%$, and chronic in $28.9\%$ and $35.8\%$, respectively. Common causes of the LBP were insidious on set with aging without known cause$(48.1\%)$, heavy work $(15.1\%)$, and trauma $(11.3\%)$. Due to LBP $12.5\%$ of the patients were not able to stand or walk for more than an hour and $2.5\%$ were bed-ridden or unable to carry out daily routine. To have the LBP diagnosed $10.2\%$ of the patients utilized a oriental medical clinic or hospital, $31.3\%$ visited a clinic or hospital, and $56.6\%$ hat not utilized any medical facility. Main reason for not having the LBP diagnosed was that the LBP was tolerable. The most popular therapeutic method that the LBP patients chose at the first was drug and physical therapy. Herb medicine was most commonly used when the first therapeutic method was not effective and the acupuncture was the most popular choice of therapy when the second therapeutic method failed. Folk medicine was utilized in $15.5\%$ of the LBP patients and it included 36 regimens such as tincture of motherwort (Leonurus sibiricus), boiled chicken with liquor, etc. It was revealed by this survey that the LBP is a serious health problem in the rural area and many of the LBP patients do not utilize a clinic or hospital but take non-scientific folk remedy. To prevent the economic waste and side effects of the folk remedy, public health education is needed for tile rational therapy of LBP.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.9
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• pp.803-810
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• 2009

This study is conducted to examine spatial variations of Dissolved Organic Matter (DOM) in stream and waste waters of the different watershed areas (agricultural, residential, and industrial complex area) by using fluorescence 3D-EEMs (3 Dimensional Excitation Emission Matrix Spectroscopy). Furthermore, the research investigates the changes of DOM characterization by synchronous and 3D-EEMs during a rainfall event. The characterizations of DOM obtained by 3D-EEMs show two noticeable peaks at humic and protein-like regions. Humic-like substances (HLS) are found in rural and urban areas, and humic and protein-like substances (PLS) are shown in industrial area. According to the fluorescence peak $T_1:C_1$ ratios, it is observed that high amount of HLS was discharged from Banweol Industrial Complex (3TG). Additionally, linear relationships (Regression rate, $r^2$=0.65, $r^2$=0.66) have been shown between PLS (peak $T_1,\;B_1$) and biochemical oxygen demand (BOD), which indicates the impact of sewage. For the rainfall event (30 mm), no remarkable difference of DOM was found at rural area except increment of fluorescence intensity comparing dry period. In contrast, HLS at urban area is highly discharged within 30 minutes from the beginning of rainfall. Also, there are high influences of HLS and PLS within 20 minutes at industrial complex (4TG). Fluorescence 3D-EEMs has not only verifies a watershed of DOM origination but also monitors diffuse and point source impacts.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.4
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• pp.372-380
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• 1996

The operation of Far East Chain(GRI 5970) of Loran - C system had been stopped on June, 1995, but that of Korean Chain(GRI 9930) of Loran - C system which was jointed with North West Pacific Chain(GRI 8930) and Russia Chain(GRI 7950) by international cooperation, was started on January 1996. In this paper, in order to study the accuracy of Loran - C fix of Korean Chain, the authors examined and analyzed the data of the reciever of Loran - C(LC -90, Furuno) and GPS(AccNav Sport super (TM), Eagle) measured automatically and continually for 2 seconds at interval of 5 minutes from November 22, 1992, to January 20, 1996 at the fixed position of National Fisheries University of Pusan, The results obtained were as follows ; 1)The mean time differences of M-W, M-X, and M-Y pair measured in the base observed position were 12333.09${\mu}$s, 28338.44${\mu}$s, and 42806.01${\mu}$s respectively and the mean standard deviations of that were 0.0121${\mu}$s, 0.0290${\mu}$s, and 0.0327${\mu}$s respectively. The daily and monthly variance forms of time difference at each pair appeared in a similar reappearance. 2)The mean standard deviations of the latitude and longitude by Loran - C were 9.1m and 17.4m in W.X pair, 11.5m and 13.7m in W.Y pair, and 8.1m and 29.3m in X.Y pair respectively, and then the probable radiuses within 95% of each pair were 39.2m, 35.7m, and 60.8m, respectively. Therefore, It is to be desired that W.Y par is selected to improve the accuracy in Pusan area. 3)The mean standard deviations of the latitude and longitude by GPS were 15.4m and 15.0m and the probable radius within 95% was 43.4m. 4)The position errors for GPS and each pair of Loran - C were 16.0m to the South in GPS and 265.2m to the East in W.X pair of Loran - C, 279.5m to the North in W.Y pair of that, and 224.3m to the North-West in X.Y pair of that, so GPS is about 250m higher than Loran - C in accuracy.