• 한국정밀공학회지
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• 제7권4호
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• pp.23-28
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• 1990

This study is to investigate the magnitude, direction and distribution of residual stresses in surface ground plate according to working conditions. The specimens were made of structural carbon steel and were machined in various grinding conditions. These were divided in two groups; heat-treated materials and non-heat-treated materials. In each working condition, let the ground specimen generate displacements using deflection-etching techniques. At the same time, these displacements were precisely measured with electronic micrometer. Through the relation formula between the plane stress and strain, which was derived using these measured data, the values of residual stress are calculated, and the results are analyzed. These results are as follows : 1. According to the working conditions in this experiment, it can be seen that the distribution of residual stress generally had same trend and the maximum residual stress remained in 20~30 ((${\mu}m$) beneath the surface. 2. It is observed that compressive residual stress changes into tensile stress in 5~20 (${\mu}m$) beneath the surface. It is suggested that such phenomenon is originated from the friction effect in grinding process. 3. As the hardness increases by the heat treatment, residual stress increases. 4. As the fatigue strength increases by the compressive residual stress, it is desirable that the dowm feed and table feed reduce. 5. It can be seen that the more great the down feed and table feed increase, the more close the changing point, where the stress changed from compressive to tensile, is colse to the surface. This is due to the resultant effects of the grinding temperature and resistence are larger than the effect of the friction.

• 생물정신의학
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• 제29권2호
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• pp.46-55
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• 2022

Objectives Many studies have reported noticeable increases in the proportion of employees working either relatively short or relatively long hours. Such trends have been accompanied by an increasing concern that how much subjective mental well-being of employees would be influenced by their hours of work. The aim of this study was to investigate the association between work hours and clinically relevant depressive symptoms with demographic variables adjusted. Methods Participants were employees of a total of 56 private companies and local government organizations in Korea, aged 19 to 65 years. A self-report questionnaire that included items on working hour, job stress, levels of depression, and socio-demographic factors was administered to 15360 Korean employees, with 14477 valid responses. Hierarchical linear regression analyses, adjusted for sociodemographic factors, job related demographic factors, job stress, were used additionally to estimate the association between working hours and depressive scores. Results We found that working more than 40 hours per week correlated positively with the level of depressive symptoms after adjusting for demographic variables and the level of job stress. Furthermore, working 40 or fewer hours per week correlated negatively with the level of depressive symptoms. Being younger (β = -0.078, β = -0.099), being a female (β = 2.770, β = 1.268), and possessing a lower level of education (β = -0.315, β = -1.125) were significantly associated with higher level of depressive symptoms in all respondents. Conclusions Both of working excessively long or short hours is significantly associated with the prevalence of depressive symptoms. Establishing proper office hours for employees is critical to improving the quality of working conditions and maintaining good mental health in the workplace.

• 사상체질의학회지
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• 제23권1호
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• pp.98-107
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• 2011

1. Objectives: In this research, job and stress of the staffs who is working on clinical trial of oriental medicine involved in the project of Korea Institute of Oriental Medicine (KIOM) was identified. And an efficient way to enhance the working ability of clinical trial of oriental medicine was developed by recognizing the relationship of job satisfaction, organizational commitment and job performance with their stress. 2. Methods: A survey was conducted on 18 staffs in 12 hospitals who is working in the project of The construction of constitutional information collecting system for the scientification of Sasang Constitution. The collected data was analyzed with computer software of SPSS 17.0 3. Results: The research results are as follows: 1. The staffs of clinical trial of oriental medicine responded that they want to receive the rewards for their work with a salary, and they felt that through clinical demonstration followed by SOP and front face photograph are the most difficult works in clinical trial of oriental medicine. 2. Permanent workers showed higher organizational commitment than temporary workers in the relationship of job satisfaction, organizational commitment and job performance with general characteristics(p=0.026). 3. In the relationship of job stress with general characteristics, the workers who are higher than college graduates had dissatisfaction in salary with the highest frequency(p=.004), and the workers whose monthly salary is higher than 2 millions won showed the lowest job stress(p=.021). 4. In the relationship of job satisfaction, organizational commitment and job performance with job stress, as job apprehension stress is increased, job performance is dramatically decreased(p=.027). And as improper salary stress is increased, job satisfaction and organizational commitment is dramatically decreased (p=.018, p=.050). 4. Conclusions: It was clearly evidenced that job satisfaction, organizational commitment and job performance is closely related with stress of the staffs who is working on clinical trial of oriental medicine. And it is highly recommended that the improvement of working condition and the decrease of job stress can enhance the working ability of them.

• 한국생산제조학회지
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• 제6권3호
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• pp.111-117
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• 1997

The sudden-stop apparatus is made to measure the residual stress of the infinitesimal area at the turning work surface by using the X-ray stress apparatus. This study is trued to make the cutting work the instantaneous stopping state in the normal working state. The behaviour of work material near the tool is estimated. The estimation method is that the distribution of residual stress can be also measured. The object is to clarify and control the mechanism to leave the adequate stress of the finishing surface. It's beginning is due to observe the occurrence state of the residual stress at the cutting work. The result obtained by this study is as follows. The chips are not separated from the work materials at all the cutting experiments of built-up edges or the shearing areas etc. which can be precisely observed by using the sudden-stop apparatus. The strain of movable system which can be seen at the part of working layer means the size of strain. This experiment proves that the working strain should be lessened to make the size of strain control the residual stress happened at the cutting surface.

• 종양간호연구
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• 제7권1호
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• pp.26-35
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• 2007

Purpose: The purpose of this study was to set the strategy that clinical nurses can efficiently cope with the stress from bereavement care, by examining and analyzing stress factors and coping methods of nurses' bereavement care. Methods: A total of 628 nurses were recruited from four university hospitals, two cancer specialized hospitals, and three public hospitals. Stress was measured using the bereavement care stress measurement tool, and coping was done using the cope with stress scale. Results: The stress level about bereavement care of the nurses working in the cancer unit was significantly higher than the level of the nurses working in the general unit. However, there was no difference of coping level between nurses working in cancer unit and general unit. Conclusions: It is important to ensure the methods that contrive to perform bereavement care efficiently by generating hospice nurses and by activating the system for nurses specialist who perform bereavement care.

• 한국직업건강간호학회지
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• 제18권1호
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• pp.106-115
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• 2009

Purpose: Occupational stress is a determinant risk factor for cardiovascular disease and work disability. This study aims to describe occupational stress and identify its related factors among aged security guards. Methods: A random sample of 76 aged security guards were interviewed by three research assistants. The criteria of the subjects were as follows : 50 or older male with 40 or more working hours a week working with colleagues ranged from 3 to 50. The data were collected in September, 2007 and analyzed by multiple regression using SAS Version 9.1. Results: The mean score of occupational stress among aged security guards was 47.2. The mean scores of its sub-scales were 31.3(physical environment), 33.8(occupational demand), 80.8occupational control), 44.6(interpersonal conflict), 51.3 (occupational insecurity), 53.6(occupational system), 57.5(lack of reward), and 30.3(work environment). The scores of occupational control, interpersonal conflict, and occupational insecurity were higher than the scores of Korean average occupational stress sub-scales. Significant variables affecting occupational stress and its sub-scales were work place, work type, and employment type. Conclusion: In order to reduce occupational stress among security guards, sufficient occupational control and interpersonal conflict control, appropriate reward, and employment stability should be considered. Also long working hours and work shift should be improved.

• 한국안전학회지
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• 제20권3호
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• pp.202-211
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• 2005

Musculoskeletal Disorders(MSDs) have been a growing problems with higher incidence rate every year. The 65% of all work-related diseases in the US has been MSDs since the middle of the 90s according to BLS(Bureau of Labor Statistics, 1995). The MSDs in Korea has been increased in recent 10 years as well. This study has tried to focus on job stress associated with MSDs that has not been usually studied before. Specifically job stress of workers at automobile manufacturing industry and relationship between job stress and symptoms of MSDs have been major concerns in this study. The workers had higher stress with longer working experience, longer working hours, and worse working environment. The job stress had strong association with the symptoms at hand, wrist and low back. Specifically, job stress factors such as job requirement and job future ambiguity had more effects on the symptoms of MSDs.

• 동서간호학연구지
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• 제15권2호
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• pp.91-101
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• 2009

Purpose: This study was performed to measure nurses' perception of job stress and job satisfaction, and to clarify the factors influential to their job satisfaction. Methods: Participants were 169 nurses working at a general hospital. Data were collected with self-administrated questionnaires and analyzed by SPSS/PC WIN 15.0. Results: Subjects perceived that job stress was higher than 'middle (3)', job satisfaction was lower than 'middle (3)', and job-related stress detrimental to job satisfaction. Influential factors for job satisfaction in a 2008 survey were duty-related stress, working conditions, and knowledge/skill-related stress. Duty-related stress and working conditions were cited as influential in a 2009 survey. The explained power for job satisfaction job was 32.5% in 2008 and 21.1% in 2009. Conclusions: Higher job-related stress detracts from job satisfaction. Hospital/nursing managers need to develop strategies that could improve the personal relationship between nurses and doctors, and provide administrative support to nurses. Provision of a financial personnel management plan could alleviate future nursing shortage triggered by job dissatisfaction.

• 구강회복응용과학지
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• 제17권4호
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• pp.283-305
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• 2001

The purpose of this study was to analyze the stress distribution of condylar regions and edentulous mandible with implant-supported cantilever prostheses on the certain conditions, such as amount of load, location of load, direction of load, fixation or non-fixation on the condylar regions. Three dimensional finite element analysis was used for this study. FEM model was created by using commercial software, ANSYS(Swanson, Inc., U.S.A.). Fixed model which was fixed on the condylar regions was modeled with 74323 elements and 15387 nodes and spring model which was sprung on the condylar regions was modeled with 75020 elements and 15887 nodes. Six Br${\aa}$nemark implants with 3.75 mm diameter and 13 mm length were incorporated in the models. The placement was 4.4 mm from the midline for the first implant; the other two in each quardrant were 6.5 mm apart. The stress distribution on each model through the designed mandible was evaluated under 500N vertical load, 250N horizontal load linguobuccally, buccal 20 degree 250N oblique load and buccal 45 degree 250N oblique load. The load points were at 0 mm, 10 mm, 20 mm along the cantilever prostheses from the center of the distal fixture. The results were as follows; 1. The stress distribution of condylar regions between two models showed conspicuous differences. Fixed model showed conspicuous stress concentration on the condylar regions than spring model under vertical load only. On the other hand, spring model showed conspicuous stress concentration on the condylar regions than fixed model under 250N horizontal load linguobuccally, buccal 20 degree 250N oblique load and buccal 45 degree 250N oblique load. 2. Fixed model showed stress concentration on the posterior and mesial side of working and balancing condylar necks but spring model showed stress concentration on the posterior and mesial side of working condylar neck and the posterior and lateral side of balancing condylar neck under vertical load. 3. Fixed model showed stress concentration on the posterior and lateral side of working condylar neck and the anterior and mesial side of balancing condylar neck but spring model showed stress concentration on the anterior sides of working and balancing condylar necks under horizontal load linguobuccally. 4. Fixed model showed stress concentration on the posterior side of working condylar neck and the posterior and lateral side of balancing condylar neck but spring model showed stress concentration on the anterior side of working condylar neck and the anterior and lateral side of balancing condylar neck under buccal 20 degree oblique load. 5. Fixed model showed stress concentration on the anterior and lateral side of working condylar neck and the posterior and mesial side of balancing condylar neck but spring model showed stress concentration on the anterior side of working condylar neck and the anterior and lateral side of balancing condylar neck under buccal 45 degree oblique load.. 6. The stress distribution of bone around implants between two models revealed difference slightly. In general, magnitude of Von Mises stress was the greatest at the bone around the most distal implant and the progressive decrease more and more mesially. Under vertical load, the stress values were similar between implant neck and superstructure vertically, besides the greatest on the distal side horizontally. 7. Under horizontal load linguobuccally, buccal 20 degree oblique load and buccal 45 degree oblique load, the stress values were the greatest on the implant neck vertically, and great on the labial and lingual sides horizontally. After all, it was considered that spring model was an indispensable condition for the comprehension of the stress distributions of condylar regions.

• 보건교육건강증진학회지
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• 제19권3호
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• pp.107-120
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• 2002

There has been a rapid industrial progress in Korea since 1962 by the success of 5-year economic development plan, and the number of industrial work has also made a rapid increase. Consequently, the management of the occupational health for the purpose of promoting the health of industrial workers and improving the working environment is badly needed in these days. Health services on industrial noisy environment have been provided only for noise-induced hearing loss management until now. But gradually, modem diseases and death have come to be related to the stress and mental health, therefore noise-induced mental disorder, like a stress became very important. Thus, this study has been carried out to analyze the relationship between workers' stress symptoms and the perceived working environment and the perceived working conditions. This study included 786 industrial workers selected from II factories in Buchun. The results were as follows: 1. For demographic characteristics, most of the workers were males(75.7%), the 20～29 years old were 33.8% and those who graduated from high school were 56.1%. The workers whose monthly income ranged from 700,000 to 1,500,000 won were 37.9% and who has a religion were 49.0%. 2. For occupational characteristics, workers who had worked 5～10 years in the factories were 35.8%. Those who felt much for them workload were 42.7% and who worked more than 8 hours a day were 73.7%. Those who were dissatisfied with their pay and job were 51.1 % and 31.2%. The workers who responded ventilation condition of their worksites were bad were 50.4% and the dissatisfied with working environment of their worksites were 43.8%. 3. For the noise exposure level in worksite, workers who were exposed to 70∼90㏈ were 37.4%, 90∼100㏈ were 25.2% and 50∼70㏈ were 18.8%. 4. Workers∼ stress symptoms were significantly related to marital status and their monthly income(P〈0.05). Workers who were single and had lower monthly income showed higher PSI(Psychiatric Symptom Index) scores than those who were married and had higher monthly income. Higher PSI scores were also significantly related to the night-work, workload, dissatisfaction with their job, and bad relationship with their bosses or co-workers. 5. The higher noise exposure level in worksite from 80㏈ was, the more severe stress symptoms including PSI subparts were reported; Anxiety, Anger, Depression, and Cognitive disorder symptom(P〈0.001). 6. According to the results of stepwise multiple regression analysis, factors affecting workers' PSI scores were noise exposure level in worksite(R2=0.150), relationship with coworkers, amount of workload, monthly income and relationship with bosses orderly and the total R2 of this 6 factors was 29.7%.