한국인 직무 스트레스 측정도구의 개발 및 표준화

장세진,고상백,강동묵,김성아,강명근,이철갑,정진주,조정진,손미아,채창호,김정원,김정일,김형수,노상철,박재범,우종민,김수영,김정연,하미나,박정선,이경용,김형렬,공정옥,김인아,김정수,박준호,현숙정,손동국 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Background and Purposes: Over the past three decades, numerous studies performed in Korea have reported that job stress is a determinant risk factor for chronic diseases and work disability. Every society has its own culture and occupational climate particular to their organizations, and hence experiences different occupational stress. An occupational stress measurement tool therefore needs to be developed to estimate it objectively. The purpose of this study is to develop and standardize the Korean Occupational Stress Scale (KOSS) which is considered to be unique and specific occupational stressors in Korean employees. Subjects and Methods: Data were obtained from the National Study for Development and Standardization of Occupational Stress (NSDSOS Project: 2002-2004). A total of 12,631 employees from a nationwide sample proportional to the Korean Standard Industrial Classification and the Korean Standard Occupational Classification were administered. The KOSS was developed for 2 years (2002-2004). In the first year, we collected 255 items from the most popular job stress measurement tools such as JCQ, ERI, NIOSH and OSI, and 44 items derived from the a qualitative study (depth interview). Forty-three items of KOSS, in the second year, were retained for use in the final version of the KOSS by using Delphi and factor analysis. Items were scored using conventional 1-2-3-4 Likert scores for the response categories. Results: We developed eight subscales by using factor analysis and validation process: physical environment (3 items), job demand (8 items), insufficient job control (5 items), interpersonal conflict (4 items), job insecurity (6 items), organizational system (7 items), lack of reward (6 items), and occupational climate (4 items). Together they explained 50.0% of total variance. Internal consistency alpha scores were ranged from 0.51 to 0.82. Twenty-four items of the short form of the KOSS (KOSS-SF) were also developed to estimate job stress in the work setting. Because the levels of the subscales of occupational stress were gender dependent, gender-specific standard norms for both the 43-item full version and the 24-item short form using a quartile for the subscales of KOSS were presented. Conclusion: The results of this study suggest that KOSS might be an appropriate measurement scale to estimate occupational stress of Korean employees. Further and more detailed study needs to be conducted to improve the validity of this scale.

SWS 490B 강의 피로균열 진전시 음향방출 거동과 파단면 관계

鄭中采,尹東珍,朴徽立,金基福,李承錫 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.8

The objective of this study was to investigate the effect of AE activities during fatigue test. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity was discussed. From the experimental results, the features of specific parameters such as the length of crack growth, the AE energy and the AE peak amplitude, showed similar trend in their increase as the stress intensity factor increased. The fracture surface of test specimens revealed both intergranular fracture and transgranular fracture. Size and density of slip band were varied as the stress intensity factor increased and AE activities were different according to the slip band shape.

농촌주민의 혈중 납과 카드뮴 농도에 관한 조사연구

정현숙,조영채,이동배 忠南大學校 環境問題硏究所 1991 環境硏究 Vol.9 No.-

The purpose of this study was to find out blood lead and cadmium concentration levels of rural residents. The blood samples were collected from 140 rural residents in 5 nonpolluted regions in Kunbuk-Myun, Kumsan-Gun, Chungnam province from August 31 to September 30, 1990 and analyzed by atomic absorption spectrophotometry. The results were summerized as follow : The mean concentration level(range) of blood lead was 0.240±0.060㎍/ml(0.130-0.390㎍/ml) for males and 0.237±0.056㎍ /ml(0.120-0.370㎍/m) for females. There was no statistically significant difference among age groups and sexes. The distributions were similar to normal distribution in both sexes. The mean concentration level(range) of blood cadmium was 0.066±0.099㎍/ml(0.012-0.582㎍/ ml) for males and 0.060±0.062㎍/ml(0.015-0.392㎍/ml) for females. There was no statistically significant difference among age groups and sexes. The distributions were skewed to the low level ranges in both sexes. The lead concentration level in whole blood did not show statistically sinificant difference among kinds of farming product. But the cadmium level of the rice-ginseng-tobacco farmers was statistically significantly high (p<0.005). The cadmium concentration level in whole blood was 0.040±0.027㎍/ml for the rice-ginseng farmers, 0.076±0.100㎍/ml ofr the rice-tobacco famers, and 0.158±0.171㎍/ ml for the rice-ginseng-to-bacco farmers. There were no statistically significant difference in blood lead and cadmuim concentration levels among groups classified by drinking habit, smoking habit and exposed years to pesticides. The correlation coefficent between the blood lead and cadmium concentration levels was statistically significant(R=0.2054, P<0.05).

랫트의 생체내 카드뮴 단독투여 및 카드뮴과 셀레늄 병용투여에 따른 필수원소의 변화

김동현,변정식,조영채,이범식,김광환,김정윤 忠南大學校 環境問題硏究所 1995 環境硏究 Vol.13 No.-

This study was performed to find out the changes of essential elements as Cu, Fe, Zn, and Ca in blood, liver, kidney and testis of rats. The experimental rats were divided into 4 groups that were consisted of control group(groupⅠ), 3.0㎎Cd/kg group(groupⅡ), 3.0㎎Cd +1.0㎎Se/kg group(groupⅢ) and 3.0mgCd+2.5mgSe/kg group(groupⅣ). Each group was intraperitoneal injection with difference dose of cadmium and selenium such as 3.0mgCd/kg, 3.0mgCd+1.0mgSe/kg and 3.0mgCd+2.5mgSe/kg. Rats were killed at the time of 3 day and 28 day, and Cd, Se, Cu, Zn and Ca concentration in several organs were determined by Atomic Absorption Spectrophotometry and inductively Coupled Plasma. Cadmium content in blood, liver, kidney and testis were significantly increased in the Cd alone injection group than Cd mixed with selenium injection groups. But, copper content were not significantly differences in control and each experimental group. Iron content were significantly increased in the Cd alone injection group than others groups. Zinc and calcium content were significantly decreased in the Cd alone injection group than other groups. On the other hand the essential element content in Cd mixed with selenium injection group were almost equaled with those of control group than Cd alone injection group.

주성분 회귀분석 및 인공신경망을 이용한 AE 변수와 응력확대계수와의 상관관계 해석

윤동진,김기복,정중채,박휘립,이승석 한국비파괴검사학회 2001 한국비파괴검사학회지 Vol.21 No.1

AE 신호와 재료의 기계적 물성과의 관계를 정량적으로 제시할 수 있는 방법을 개발하였다. 재료의 여러 가지 기계적 성질들 중 피로균열 거동에 관련된 응력확대계수를 중심으로 AE 신호와 같은 다변량 데이터의 처리에 많이 사용되고 있는 주성분 회귀분석과 비선형적 문제 해결에 적합한 신경회로망 기법을 이용하였다. 이를 위하여 강교량 부재인 SWS490B 강에 대한 피로균열전파 실험을 수행하였으며 표준 CT 시편에 대한 피로균열진전 시 발생하는 AE 신호의 각 변수와 응력확대계수와의 관계를 고찰하였다. 통계분석 방법인 변수선택법을 적용한 결과 AE 카운트(RC), 에너지(EN), 신호지속시간(ED)의 각각에 대한 유의성이 높은 것으로 나타났으나 전반적으로 전체 AE 변수를 모두 이용할 경우 통계적 유의성이 높은 것으로 나타났다. 부재의 반복하중 시 발생하는 피로균열진전을 정량적으로 도출할 수 있는 응력확대계수 추정모델을 개발하고 평가하였다. 미지 시료에 대하여 개발된 모델의 응력확대계수 예측 성능을 분석한 결과 주성분 회귀모델과 인공신경망 모델 모두 우수한 예측성능을 나타내었으나 전반적으로 인공신경망 모델이 주성분 회귀모델보다 다소 양호한 것으로 분석되었 다. The aim of this study is to develop the methodology which enables to identify the mechanical properties of element such as stress intensity factor by using the AE parameters. Considering the multivariate and nonlinear properties of AE parameters such as ringdown count, rise time, energy, event duration and peak amplitude from fatigue cracks of machine element, the principal component regression(PCR) and artificial neural network(ANN) models for the estimation of stress intensity factor were developed and validated. The AE parameters were found to be very significant to estimate the stress intensity factor. Since the statistical values including correlation coefficients, standard error of calibration, standard error of prediction and bias were stable, the PCR and ANN models for stress intensity factor were very robust. The performance of ANN model for unknown data of stress intensity factor was getter than that of PCR model.

일부 산업장근로자들의 피로자각증상과 일상생활요인과의 관련성

김정윤,조영채,이동배,박내경 大韓産業醫學會 1998 대한직업환경의학회지 Vol.10 No.2

For the purpose of obtaining reference materials for the prevention and management of mental health promoting in industrial workers, this survey was investigated the relationship between subjective fatigue symptoms and its related factors such as demographic, job and health related variables. 442 cases of industrial workers which occurred in 7 factories of machine and metal manufacturing industries in Taejon industries area surveyed by self-recorded questionnaire. The results were as following: 1. In the complaint rates of fatigue, "eye strain" was the highest(21.9%) and followed by "feel like lying"(12.4%) and "feel a pain in the low back"(12.4%), "feel drowsy"(12.2%), "yawning a lot"(11.8%) and "whole body feels tired"(11.1%) in the descending order. 2. In the average weighted scores of fatigue complaints, dullness and sleepness group(Ⅰ) was the highest, followed by difficulty in concentration group(Ⅱ) and bodily projection of fatigue group(Ⅲ) in the descending order. 3. The average weighted scores of fatigue complaints by general characteristics were significantly higher in the lower age group, lower education group and unmarried divorce group. But there was no significant difference in sex. 4. By the working condition, the fatigue scores were significantly higher in manual workers and shift worker than in clerical worker and day worker. 5. By the life style, the fatigue scores were significantly lower in 7-8 sleeping hour group and every day eating breakfast group than in other groups. But fatigue score of everyday alcohol drinking group and the lower health practice indecies group were significantly higher than that of other groups. 6. By the health status and psychological factors, the fatigue scores were higher in unhealthy group, unsatisfaction income level group, unsatisfaction worker contents group and the group of badly self-control in work. 7. In the stepwised multiple regression, factors affecting the fatigue symptoms scores were depression symptom score, health status, marital status, job satisfaction, job repeatedness and body mass index.

cDNA array 방법을 이용한 망간에 노출된 흰쥐 뇌기저핵의 유전자발현 분석

이채관,노성민,문덕환,,김정호,손병철,김대환,이창희,김휘동,김정원,김종은,안진홍,이채언 大韓産業醫學會 2005 대한직업환경의학회지 Vol.17 No.4

Objectives: This study investigated the gene expression profile in basal ganglia of manganese-exposed rats based on cDNA array analysis. Methods: For cDNA array, 25 male Sprague-Dawley rats (250±25 g) were intraperitoneally injected with 25 ㎎/㎏ B. W./day of MnCl2 (0.3 ㎖) for 10 days. For dose-related gene expression analysis, rats were intraperitoneally injected with 0.2, 1.0, and 5.0 ㎎/㎏ B. W/day of MnCl2 for 10 days. Control rats were injected with an equal volume of saline. RNA samples were extracted from brain tissue and reverse-transcribed in the presence of [α^(32)P]-dATP. Membrane sets of the Atlas Rat 1.2 array Ⅱ and Toxicology array 1.2 kit (Clontech, Palo Alto, CA) were hybridized with cDNA probe sets. Northern blot hybridization method was employed to assess the dose-related gene expression. Results: Fifty-two genes showed significant changes in expression of more than two-fold. Twenty-eight were up-regulated and 24 were down-regulated in the manganese-exposed group compared to the control. Among the 52 genes, 28 genes including nuclear factor I-X1 (NF1-X1), neuroligin 2 and 3, mitochondrial stress-70 protein (MTHSP70), neurodegeneration-associated protein 1 (Neurodap 1), multidrug resistance protein (MDR), and endoplasmic reticulum stress protein 72 (ERP72), were reported for the first time related to the manganese-induced neurotoxic-metabolism in the rat basal ganglia. According to the dose-related gene expression analyses, MTHSP70, Neurodap 1 and ERP72 genes were up-regulated compared to the control even in the group exposed to low manganese dose ( 0.2 ㎎/㎏ B.W./day). Conclusions: Twenty-eight genes detected for the first time in this study were closely related to the manganese-induced neurotoxic-metabolism in the rat basal ganglia and further study of these genes can give some more useful information about the manganese metabolism.

동맥내막절제술과 동맥내 스텐트 삽입술을 이용한 청색지증후군 치험 2예 : 2 Cases Report

권정남,박동은,채권묵,노병석,소병준 대한혈관외과학회 2003 Vascular Specialist International Vol.19 No.1

응력확대계수와 음향방출 변수를 이용한 피로균열 거동 연구

윤동진,정중채,박휘립,김기복,이승석 한국비파괴검사학회 2000 한국비파괴검사학회지 Vol.20 No.5

응력확대계수와 음향방출 발생 관계를 이용해 균열 길이 및 균열 검출 능력을 평가할 수 있는 새로운 접근 방법을 파괴역학적인 관점에서 제시하였다. 이를 위해 강 교량 부재인 SWS 490B 강의 피로 균열 활동도를 음향방출시험을 통해 관찰하였다. 표준 CT 시편에 대한 피로균열 진전 시 AE 특성을 관찰하는 실험을 진행하였으며, 기존의 AE 파라미터 분석은 물론 응력확대계수와 AE 발생거동 사이의 관계를 논의하였다. CT 시편 실험 결과에서 균열 성장 길이, AE 최대진폭, AE 에너지, AE hit 발생율 등과 같은 특정 변수들은 응력확대계수 값이 증가함에 따라 이들값도 증가하는 경향을 나타내었다. 또한 피로사이클 수에 따른 AE 에너지의 변화는 균열진전에 대한 활동성을 평가하는데 사용되는 효과적인 변수중의 하나임을 보여 주었으며, AE 에너지 분석은 균열 활동도와 AE 변수 사이의 관계를 평가하는데 사용될 수 있을 것으로 판단된다. By using the relation between stress intensity factor and AE parameter, new approach method for assessing the crack length and detectability of crack was proposed. Laboratory experiment was carried out to identify AE characteristics of fatigue cracks for compact tension specimen. The relationship between a stress intensity factor and AE signals activity as well as conventional AE parameter analysis was discussed. As a result, the features of specific parameters such as the length of crack growth, the AE energy, the AE peak amplitude, and the cumulative AE hits, showed the almost same trend in their increase as the number of fatigue cycle increased. From the comparisons of peak amplitude and AE energy with stress intensity factor, it was verified that the higher stress intensity factors generated AE signals with higher peak amplitude and a larger number of AE counts. If we can get more reliable database for the relation between AE parameters and stress intensity factor, this approach will provide a good information for evaluating both the existence of crack and the minimum detectable size of crack.

LCD산업의 성과분석과 리더쉽 유지가능성에 대한 고찰

이정동,유진혁,임채윤,박성배 한국생산성학회 2001 生産性論集 Vol.15 No.2

Learning effect has implication for the performance analysis for the LCD industry which is highly process oriented and capital intensive industry. In this study, we estimate the learning parameter in that industry and investigate the difference in learning across generations. Based on the estimated learning effect, we provide some implication for the question whether the leadership in the industry is sustainable or not.