• Journal of Industrial Convergence
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• v.21 no.5
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• pp.77-85
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• 2023

Suicide is the leading cause of death among Korean adolescents. There is a growing interest in the role of loneliness as a risk factor for suicide ideation and depressive symptoms. However, little is known in the Korean context. This study analyzed a total of 109,796 respondents from the Korea Youth Health Behavior Survey in 2020 and 2021. Multiple logistic regression models were implemented to test the association between loneliness and either of suicidal ideation and depressive mood. Covariates included demographic characteristics, school enrolled, household income, living arrangement, self-rated health, and the number of times treated for violence. Adjusted odd ratio (OR) and 95% confidence intervals (CI) were computed. 12.0% of adolescents reported to have felt lonely frequently and 3.0% always. 11.8% and 26.0% had suicidal ideation and depressive mood, respectively. The prevalence of suicidal ideation was higher in the always-lonely adolescents (52.6%) than in the frequently-lonely adolescents (35.1%). The always-lonely adolescents were nearly 30 times more likely to have suicidal ideation (OR=30.7; 95% CI, 27.1 - 34.8) and to feel depressed (OR=32.5; 95% CI, 29.2 - 36.4) than adolescents who felt never lonely. In conclusion, Loneliness was a major risk factor for suicidal ideation and depressive mood among Korean adolescents. Monitoring and addressing the condition of loneliness may help reduce suicidal ideation and depressive mood.

• Journal of Preventive Medicine and Public Health
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• v.35 no.3
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• pp.245-254
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• 2002

Objective : To test if the intake of $H_2$ receptor antagonists ($H_2$-RAs) increases the risk of gastric cancer in the elderly. Methods : The source population for this study was drawn from the responders to a questionnaire survey administered to the Korea Elderly Pharmacoepidemiological Cohort (KEPEC), who were beneficiaries of the Korean Medical Insurance Corporation, were at least 65 years old, and residing in Busan in 1999. The information on $H_2$-RAs exposure was obtained from a drug prescription database compiled between inn. 1993 and Dec. 1994. The cases consisted of 76 gastric cancer patients, as confirmed from the KMIC claims data, the National Cancer Registry and the Busan Cancer Registry. The follow-up period was from Jan. 1993 to Dec. 1998. Cancer free controls were randomly selected by 1:4 individual matching, which took in to consideration the year of birth and gender. Information on confounders was collected by a mail questionnaire survey. The odds ratios, and their 95% confidence intervals, were calculated using a conditional logistic regression model. Results : After adjusting for a history of gastric ulcer symptoms, medication history, and body mass index, the adjusted OR (aOR) was 4.6 (95% CI=1.72-12.49). The odds ratio of long term use (more than 7 days) was 2.3 (95% CI=1.07-4.82). The odds ratio of short term use was 4.6 (95% CI=1.26-16.50). The odds ratio of parenteral use was 4.4 195% CI=1.16-17.05) and combination use between the oral and parenteral routes (aOR, 16.8; 95% CI=1.21-233.24) had the high risk of gastric cancer. The aOR of cimetidine was 1.7 (95% CI=1.04-2.95). The aOR of ranitidine was 2.0 (95% CI=1.21-3.40). The aOR of famotidine was 1.7 (95% CI=0.98-2.80). Conclusion : The intake of $H_2$-RAs might increase the risk of gastric cancer through achlorhydria in the elderly.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.1
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• pp.1-7
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• 2009

Purpose: The purpose is to evaluate the accuracy of correcting the targeting error through the Target Location System (TLS) for the location change error of the reference point which arises from the movement or motion of patient during the treatment using the CyberKnife. Materials and Methods: In this test, Gafchromic MD-55 film was inserted into the head and neck phantom to analyze the accuracy of the targeting, and then the 6 MV X-ray of CyberKnife (CyberKnife Robotic Radiosurgery System G4, Accuray, US) was irradiated. End to End (E2E) program was used to analyze the accuracy of targeting, which is provided by Accuray Corporation. To compute the error of the targeting, the test was carried out with the films that were irradiated 12 times by maintaining the distance within the rage of $0{\pm}0.2\;mm$ toward x, y, z from the reference point and maintaining the angle within the rage of $0{\pm}0.2^{\circ}$ toward roll, pitch, yaw, and then with the films which were irradiated 6 times by applying intentional movement. And the correlation in the average value of the reference film and the test film were analyzed through independent samples t-test. In addition, the consistency of dose distribution through gamma-index method (dose difference: 3%) was quantified, compared, and analyzed by varying the distance to agreement (DTA) to 1 mm, 1.5 mm, 2 mm, respectively. Results: E2E test result indicated that the average error of the reference film was 0.405 mm and the standard deviation was 0.069 mm. The average error of the test film was 0.413 mm with the standard deviation of 0.121 mm. The result of independent sampling t-test for both averages showed that the significant probability was P=0.836 (confidence level: 95%). Besides, by comparing the consistency of dose distribution of DTA through 1 mm, 1.5 mm, 2 mm, it was found that the average dose distribution of axial film was 95.04%, 97.56%, 98.13%, respectively in 3,314 locations of the reference film, consistent with the average dose distribution of sagittal film that was 95.47%, 97.68%, 98.47%, respectively. By comparing with the test film, it was found that the average dose distribution of axial film was 96.38%, 97.57%, 98.04%, respectively, at 3,323 locations, consistent with the average dose distribution of sagittal film which was 95.50%, 97.87%, 98.36%, respectively. Conclusion: Robotic CyberKnife traces and complements in real time the error in the location change of the reference point caused by the motion or movement of patient during the treatment and provides the accuracy with the consistency of over 95% dose distribution and the targeting error below 1 mm.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.271-275
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• 2009

본 연구에서는 상수관로의 잔존수명을 통계적 기법 중 하나인 비례위험모형(PHM)에 적용하여 평가하였다. 비례위험모형을 구축하기 위한 개별관로의 생존시간은 관로의 파손율이 한계파손율에 도달하는 시간으로 정의하였다. 즉, Park and Loganathan(2002)에서 제시한 GPBM을 적용하여 시간에 따른 개별관로의 파손율을 추정하고 추정된 파손율과 한계파손율의 상등관계를 통해 생존시간을 산정하였다. 또한, 본 연구대상관로에 대한 GPBM을 구축함에 있어, 매설시점에서 누적파손횟수를 0으로 한 파손기록을 입력자료에 추가하는 방법과 가중계수(WF)의 범위를 수정함으로써 기존의 GPBM을 보완하였다. 이로써 파손사건이 최소 1회 이상 기록된 강관 및 주철관에 대한 비례위험모형을 구축하였다. 이와 같이 수정된 방법론은 관로 파손사건 등의 자료의 축적이 미비한 국내 여건에서 비례위험모형 및 GPBM과 같은 통계적 모형을 구축할 때 유용할 것으로 사료된다. 본 연구대상관로의 비례위험모형에 포함된 유의한 공변수는 관종과 관경 그리고 길이이며 관종은 비례성 가정을 위배하여 시간종속형 변수로 모형화되었다. 최종 채택된 PHM모형을 통해 생존함수를 추정하였으며 추정된 생존함수를 이용하여 개별관로의 잔존수명 및 경제적 수명 그리고 각 수명에 대한 95% 신뢰구간을 산정하였다. 또한 개별관로의 경제적 수명에 영향을 미치는 공변수의 위험비율도 분석하였다. 분석결과 강관의 평균 경제적 수명은 약 25.1년이고 주철관은 약 21년으로 산정되었다. 또한 관종에 따른 경제적 수명에 도달할 상대적인 위험률은 전반적으로 주철관이 높으나 20년 이상 매설된 관로에서는 강관의 위험률이 높을 것으로 분석되었다. 관경과 길이는 크기에 비례하여 상대적 위험률도 증가하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1186-1193
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• 2012

The purpose of the study is to provide the basic data for preventing and caring cardiovascular disease. The study was performed with the data from the same 1,668 persons who had medical checkup three times from 2004 to 2008 at a health promotion center. The related factors were examined with Cohort Study. The result of the study is as followed, The incidence of metabolic syndrome for the subjects from 2004 to 2008 increased; 0% in 2004, 8.3% in 2006 and 12.0% in 2008. Multiple logistic regression analysis showed that the related factors in the occurrence of metabolic syndrome which changed from the non metabolic syndrome group in 2004 to metabolic syndrome were age, smoking, total cholesterol, ALT, and uric acid etc.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.265-274
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• 2000

Relationship between the daily mortality and total suspended particulate(TSP) for the period of 1996-1997 was examined in Seoul, Korea. Generalized additive model was adapted for the analysis to allow the seasonality and long-term time effect in the air pollution and the nonlinear relationships with weather variables such as air temperature and relative humidity. An increase of 100 Ji9/m') TSP corresponds to 0.8-5.2 percent increase of the daily mortality Unidirectional (prospective and retrospective) case-crossover design results in large bias of the estimates. Bidirectional method gives relatively unbiased estimates but the standard errors are larger Case-crossover design should be used with caution in the situation where the data have seasonal trends like air pollution study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.3 no.3
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• pp.95-106
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• 1983

The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; $$P_f$$=M/N N: Total number of trials M: Total number of failures some of the conclusions derived from the case study include; 1. If the strength parameters are assumed to be normal variated, the relationship between safety factor and the probability of failure is fairly consistent, regardless of the procedures of analysis and dimensions of assumed rupture surfaces. 2. However if the strength parameters are beta variated, general relationship between $F_s$ and $P_f$ is hardly found.

• Korean Journal of Clinical Pharmacy
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• v.16 no.1
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• pp.69-74
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• 2006

날트렉손은 ${\mu}-opioid$ 수용체에 특이적이고 선택적으로 길항작용을 나타내어 마약이나 마약성 진통제의 강한 의존성 치료에 쓰일 뿐만 아니라, 알코올 의존성 치료에도 쓰이는 약물이다. 본 연구는 날트렉손 제제인 레비아 정 (50 mg tablet, 제일약품) 을 대조약으로 하여 시험약인 명인 제약의 트락손 50 mg정의 생물학적 동등성 평가를 하기 위해 22명의 건강한 지원자를 모집하였다. 지원자를 두 군으로 나누어 1정씩 투여하였고 $2{\times}2$ 교차시험을 실시하였다. 날트렉손의 혈장 중의 농도를 정량하기 위하여 발리데이션된 LC/MS/MS를 사용하였다. 채혈 시간은 투약 전 및 투약 후 0.25, 0.5, 0.75, 1, 1.5, 2, 3, 4, 6, 9, 12 시간에 걸쳐 시행하였다. 생물학적 동등성을 판정하기 위한 파라미터로 12시간까지의 혈장 중 농도 곡선 하 면적$(AUC_{12hr})$과 최고 혈중 농도 $(C_{max})$를 사용하였다. $AUC_{12hr}$의 평균은 $43.45ng{\cdot}hr/ml$ (시험약)과 $43.31ng{\cdot}hr/ml$ (대조약) 으로 관찰되었고, $C_{max}$의 경우 각각 12.01 ng/m1 (시험약)과 12.27 ng/ml (대조약)으로 관찰되었다. $AUC_{12hr}$의 경우 로그변환 한 평균치 차의 90%의 신뢰구간이 log0.95-log1.07이었고, $C_{max}$의 경우 log0.87-log1.14로 계산되어 두 항목 모두 log0.8-log1.25이어야 한다는 식품의약품 안전청과 FDA의 기준을 모두 만족시켰다. 이상의 결과를 종합하면 시험약 트락손 정 50mg 은 대조약 레비아 정 50 mg에 대하여 생물학적으로 동등한 것으로 판정되었다.

• Korean Journal of Clinical Pharmacy
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• v.15 no.2
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• pp.160-164
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• 2005

수마트립탄은 뇌혈관에 분포되어 있는 5-HT1B/1D수용체에 특이적이고 선택적으로 작용하여 뇌혈관 수축 작용을 나타내어 편두통의 치료에 널리 쓰이는 약물이다. 본 연구는 수마트립탄 제제인 이미그란(50 mg tablet, GSK사)을 대조약으로 하여 시험약인 명인 제약의 수마트란 50mg정의 생물학적 동등성 평가를 하기 위해 22명의 건강한 지원자를 모집하였다. 지원자를 두 군으로 나누어 1정씩 투여하였고 $2{\times}2$ 교차시험을 실시하였다. 수마트립탄의 혈장 중의 농도를 정량하기 위하여 발리데이션된 HPLC/FD를 사용하였다. 채혈 시간은 투약 전 및 투약 후 0.5, 1, 1.5, 2, 2.5, 3,4, 5, 7, 9, 12시간에 걸쳐 총 12시점에 걸쳐 시행하였다. 생물학적 동등성을 판정하기 위한 파라미터로 12시간까지의 혈장 중 농도 곡선 하 면적$(AUC_{12hr})$ 최고 혈중 농도$(C_{max})$를 사용하였다. $AUC_{12hr}$의 평균은 $137.87ng{\cdot}ml/hr$(시험약)과 $130.12ng{\cdot}ml/hr$(대조약)으로 나타났다. $C_{max}$의 경우 각 각 29.30 ng/ml(시험약)과 29.25ng/m1(대조약)으로 관찰되었다. $AUC_{12hr}$의 경우 로그변환 한 평균치 차의 90% 신뢰구간이 log0.95-log1.24이었고, $C_{max}$의 경우 log0.90-log1.149로 계산되 어 두 항목 모두 log0.8-log1.25이어야 한다는 식품의 약품 안전청 과 FDA의 기준을 모두 만족시켰다. 이상의 결과를 종합하면 시험약 수마트란 정 50 mg은 대조약 이미그란 정 50 mg에 대하여 생물학적으로 동등한 것으로 판정되었다.

• Journal of Sensor Science and Technology
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• v.11 no.3
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• pp.125-131
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• 2002

Respiratory air flow rate is necessarily measured for the pulmonary function evaluation. The currently used devices are exposed to the problems of measurement reliability and cross-patient infection. The present study introduced a new technique which converted the bidirectional air flow rate into averaged dynamic pressure based on the famous Bernoulli's energy conservation principle. Single use plastic sensing element was assembled within the flow tube(mouth piece) made of paper, which was named "functional single use flow tube". Experiment demonstrated only ${\pm}1.5%$ relative error in the standard 3L volume measurement procedure well within the error limit suggested by the American Thoracic Society(ATS). Disposable use design completely eliminated cross-patient infection. The present device is best useful and safe for clinical respiratory air flow measurement such as spirometry.