자동차 조립작업자의 사회ㆍ심리적 스트레스와 근골격계 증상과의 연관성

김일룡,김재영,박종태,최재욱,김해준,염용태 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.3

목적 : 이 연구는 자동차 조립라인 근로자들의 사회·심리적 스트레스와 작업관련 근골격계 자각증상간의 연관성을 확인하는 데에 있다. 방법 : 경인지역 소재 자동차 회사 두곳의 조립라인에 근무하는 근로자 636명을 대상으로 하여, 근골격계 자각증상에 대해서는 목과 어깨, 팔과 팔꿈치,. 손목과 손, 허리부위에서의 통증, 쑤심, 뻣뻣함, 화끈거림, 무감각 또는 저림 등을 묻는 표준화된 설문지로 질문하였고, 스트레스 정도는 4개 분야, 45개 항목으로 이루어진 Psychosocial Well-being Index 설문지를 배포후 3점 척도를 적용하였다. 이들간에는 카이자승법, ANOVA rm리고 로짓회귀분석을 사용하여 통계적으로 유의한 연관성을 알고자 하였다. 결과 : 1. 수면시간을 제외하고 연령, 근속기간, 결혼여부, 학력수준, 흡연력, 음주력에 따른 상지근골격계 증상의 빈도 차이는 없었다. 2. 30세 미만의 작업자군에서 사회 심리적 스트레스 점수(p-value: 0.0461)와 스트레스 Factor 3 (p-value: 0.0368), Factor 4 (p-value: 0.0053)의 점수가 높았다. 3. 11∼15년의 근속기간을 가진 작업자의 경우 Factor 1을 제외한 PWI(p-value: 0.0001), Factor 2(p-value:0.0001), Factor 3(p-value: 0.0004), Factor 4(p-value: 0.0001)에서 기타의 근속기간을 갖는 동료에 비해 높은 스트레스 점수를 보였다. 4. 미혼자는 Factor 4에서 기혼자보다 높은 스트레스 점수를 보였다(p-value: 0.0068). 5. 수면시간이 6시간 이하인 작업자군은 6시간을 초과하는 작업자보다 PWI(p-value: 0.0087), Factor 2(p-value: 0.0194), Factor 3(p-value: 0.0048), Factor 4(p-value: 0.0314) 등에서 높은 스트레스 점수를 보였다. 6. 스트레스 점수는 정규분포를 이루었으며 정상군과 스트레스위험군간에 증상의 빈도 차이는 없었다. 7. 근골격계 증상이 있는 작업자군은 무증상군과 비교하여 기타 스트레스 점수는 두 군간에 유의한 차이가 없었으나, Factor 2에서 통계적으로 유의하게 높은 스트레스 점수를 보였고(p-value: 0.028), 단변량(OR: 1.02) 및 다변량(OR: 1.04) 로짓 회귀분석에서도 Factor 2가 양의 회귀계수(0.0226; 0.0352)를 보여 증상에 영향을 주는 것으로 나타났다. 결론 : 근골격계 자각 증상이 있는 조립작업자군은 증상이 없는 군에 비해 우울증 항목에서 높은 스트레스 점수를 보였으나 기타 사회적 역할 수행 및 자기신뢰도, 수면장애 및 불안, 일반건강 및 생명력등의 사회심리적 스트레스 항목에서는 두 군간에 유의한 차이를 보이지 않았다. 로짓회귀분석예서도 우울증이 근골격계 증상에 영향을 주는 것으로 나타나서 비록 제한적이지만 우울증에 해당하는 항목인 Factor 2와 증상간의 연관성을 일부 확인할 수 있었다. 그러나 근골격계 증상발현에는 스트레스 이외에도 인간공학적 혹은 알려지지 않은 요인들 중요하게 작용하므로 이들을 통제한 후의 추가적인 조사를 해야 할 것으로 생각된다. Objectives : To determine the relationship between stress Factors and work-related muscul-loskeletal symptoms of assembly line workers in the automobile industry. Methods : A cross-sectional study was conducted in two Factories of automobile manufacturing companies where inappropriate posture and repetitive motions were required. The total number of subjects was 636, and consisted entirely of men. The Age, length of work duration, marital status, education level, smoking status, drinking status, sleeping time and stress scores were investigated according to subgroups of general characteristics. We divided the subjects into a Reference group and a Stress risk group to compare the frequency of the variables between them. The stress scores of the Positive symptom group were compared with the Symptom free group by the t-test. To measure the stress level, the PWI(Psychosocial Well being Index) which consists of 4 Factors, totaling 45 items, was used. A standardized self-reported questionnaire was used to assess the symptoms in workers. The criteria for positive symptoms were based on Operational Definition of Work-related Musculoskeletal Disorders of the NIOSH. Results : 1) The subgroups of Age, Work duration, Marital status, Education level, Smoking status, Drinking status and Sleeping time revealed no differences in frequencies in musculoskeletal symptoms. 2) Higher PWI(p<0.05), Factor 3(p>0.05) and Factor 4(p<0.01) scores were observed in younger workers compared with older workers. 3) The workers who had work durations betwen 11-15 years showed higher PWI(p<0.01), Factor 2(p<0.01), Factor 3(p<0.01), and Factor 4(p<0.01), compared with other work duration subgroups. 4) Singles had higher Factor 4 scores(p<0.01). 5) The sleeping time of less than 6 hours a day expressed a higher PWI(p<0.01), Factor 2(p<0.05), and Factor 3(p<0.01), Factor 4(p<0.05). 6) There was no difference in the prevalence of musculoskeletal symptoms between the Reference group and Stress risk group. 7) The subjects who had Positive musculoskeletal symptoms showed a significant difference in Factor 2 scores compared with the Symptom free groups. 8) According to a univariate logistic regression analysis, Factor 2(OR: 1.02, 95% CI:1.00-1.04, p-value: 0.0291) expressed significant but mild effects on the musculoskeletal symptoms and a multivariate logistic regression showed a statistically significant effect on musculoskeletal symptoms(OR:1.04, 95% CI: 1.01-1.07, p-value: 0.0170). Conclusion : Psychosocial stress scores were not higher in symptomatic subjects compared with those who had no symptoms. Sleeping longer showed a protective effect on symptoms but this was not statistically significant. There was no relationship between the stress scores and musculoskeletal symptoms in social performance and self-confidence, general well-being and vitality. Factor 2(Depression) was statistically significant though its effect was mild. Limited to this study, We could find partial relationship between psychosocial stress(Depression) and musculoskeletal symptoms. So it could therefore be suspected that ergonomic or other unknown factors may be more significant causes of musculoskeletal symptoms but we did not investigate these.

몬테카를로 방법에 의한 수소분자의 기저상태 에너지의 수치 해석적인 계산

양해정,양회룡,정진,김미정,최승평,장차익 조선대학교 기초과학연구소 2000 自然科學硏究 Vol.23 No.1

Numerical methods that are known as Monte as Monte Carlo methods can be loosely described as statistical simulation methods, where statistical simulation is defined in quite general terms to be any method that utilizes sequences of random numbers to perform the simulation. Monte Carlo methods are now used routinely in many problems, the simulation of the esoteric subnuclear processes in high energy physics experiments, cellular automata, self-organized critical phenomena, the Ising spin glass, the simulation of a Bingo game, etc. The physical processes are simulated directly, and there are no needs to even write down the differential equations that describe the behaviors of the systems. The only requirement is that the physical systems be described by probability density functions. We consider with the Monte Carlo variational method and the Monte Carlo path integral method(MCPI). These methods are used to calculate the energy of the ground states of H2 molecule by the formal similarity between the Schroedinger equation and the multi-dimensional diffusion equation.

CO₂아크용접기를 위한 3상 전압형컨버터의 입력역률개선

최규하,최해룡,김홍성 건국대학교 산업기술연구원 2000 건국기술연구논문지 Vol.25 No.-

Diode rectifier has been widely used as preregulator in CO2 arc welding machine, which has an advantage of low cost in application field. One of the demerits of diode-bridge rectifiers, is the line-current harmonic caused by the nonlinear nature of rectifier operation. As it is linked to power utility, a disorder of other instruments can be burst out, and the reactive power degenerates the total system efficiency The adoption of voltage source PWM converters can be considered and it must catch the compromise of system performance and cost. So, in this paper voltage source converters which have single and six control switch respectively, are analyzed and confirmed through digital simulation and experiments. In addition the improved input characteristics of CO2 arc welding machine known as low power factor system with nonlinear property, are shown and evaluated compared to conventional one.

He 원자의 가장 낮은 들뜬 상태 에너지의 수치 계산

차혁렬,양해정,김미정,정진,양회룡,최승평,장차익 조선대학교 기초과학연구소 1999 自然科學硏究 Vol.22 No.1

The one-electron theory of atoms, molecules, and crystals have enjoyed a wide success in many branches of physics. This theory provides a physically appealing description of the electronic structure of many-electron systems. In addition, this theory gives a convenient basis for performing the detailed calculation on specific many-electron systems. In such calculations, it is usually necessary to introduce many simplified assumptions in order to make a progress. Since the principal computational difficulty supposed by the Hartree-Fock equations is the treatment of the exchange term, it would be very desirable to simplify the treatment of these terms by using Slater's average of the exchange potential. The first order correction of energy in the lowest excited states of He atom is calculated by using the unperturbed wave function obtained with the Hartree-Fock-Slater approximation and compared with the result obtained by the simple analytical method. The numerical results agrees with an experimental results for the lowest excited states of He atom with tolerance 3.22%, 2.16%, 2.94% and 3.41%. These results show that the numerical analysis can be applied to other multielectron atoms with the personal computer.

강자성체에서 상전이의 수치적 모의실험

유대영,양해정,양회룡,정진,최승평,장차익 조선대학교 기초과학연구소 2001 自然科學硏究 Vol.24 No.-

It is difficult to explain the magnetic phase transition with classical physics in Curie temperature. We studied qualitatively with the well known Ising model in statistical mechanics. We simulated systems of finite size by Monte Carlo methods with Metropolis algorithm. Thus we could estimate the values of quantities such as the magnetization(m) per spin the specific heat(c) per spin the magnetic susceptibility(χ) per spin, and the mean energy per spin compare with the numerical values in infinitive size. The quantities of c, m, χ, e varied rapidly within 2.3∼2.4 temperature at J/k units. Those values show that the critical temperature can be within the range. The hysteresis loop was obtained with this model.

A study on Power Factor and Dynamics in Arc Welding System Using Single Switched PFC Converter

Choi,Hae-Ryong,Mok,Hyung-Soo,Goo,Young-Mo,Choe,Gyu-Ha,Kim,Gyu-Sik,Won,Chung-Yun 성균관대학교 1998 학술회의지원논문목록집 Vol.1998 No.-

An arc welding machine using single switched PFC converter is presented in this paper. First the basic operation and principle is reviewed. Controller design is intended to force voltage ripple to minimize, and dynamis response to enhance Feed-forward strategy for arc welding machine is developed, and that is verified by simulation. The improved power factor characteristics of arc welding machine known as low power factor system with nonlinear property, are shown and evaluated compared to conventional one.

A Study on Power Factor and Dynamics in Arc Welding System Using Single Switched PFC Converter

Hae-Ryong Choi,Young-Mo Goo,Gyu-Ha Choe,Hyung-Soo Mok,Gyu-Sik Kim,Chung-Yun Won 전력전자학회 1998 ICPE(ISPE)논문집 Vol.- No.-

An arc welding machine using single switched PFC converter is presented in this paper First, the basic operation and principle is reviewed Controller design is intended to force voltage ripple to minimize, and dynamic response to enhance. Feed-forward strategy for arc welding machine is developed, and that is verified by simulation. The improved power factor characteristics of arc welding machine known as low power factor system with nonlinear property, are shown and evaluated compared to conventional one.<br/>

A Study On Novel MPPT Method Using Averaging of Voltage Ripple

Hae-Ryong Choi,Jae-Surk Gho,Gyu-Ha Choe,Heung-Geun Kim,Woo-Surk Shin 전력전자학회 2001 ICPE(ISPE)논문집 Vol.2001 No.10

Of two photovoltaic systems such as stand-alone type and utility interactive one, the utility interactive systems are so valuable for power peak-cut particularly in summer season For the maximum power point tracking(MPPT) by which the generating energy can be maximized, many control methods have been reported up to now. To overcome the disadvantages of the conventional ones, a new MPPT algorithm is proposed which can improve both tracking ability and generating efficiency of photovoltaic system without chopper.<br/>

Power Factor Correction of Three Phase Voltage Source PWM Converter for Inverter Arc Welding Machine

Hae-Ryong Choi,Hong-Sung Kim,Seong-Yo Lee,Hyung-Soo Mok,Gyu-Ha Choe 전력전자학회 2000 전력전자학술대회 논문집 Vol.2000 No.11

Diode rectifier has been widely used as the preregulator of inverter arc welding machine(IAW). As it is linked to power utility, a disorder of other instruments can he burst out. The adoption of voltage source PWM converters can he considered, and which must catch the compromise of between performance and cost. So, in this paper voltage source PWM converters which have single(i.e. SMR) and six(i.e. PWM converter) control switch respectively, are analyzed and evaluated through digital simulation and experiment. In addition the improved input characteristics of IAW are shown and compared to those of conventional one.

진한 연명의 형성과 변천 (하)

최해용(Choi Hae Ryong) 대구사학회 1997 대구사학 Vol.53 No.1

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