• Journal of the Ergonomics Society of Korea
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• v.15 no.2
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• pp.51-62
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• 1996

This research utilized the psychophysical methodology, where secrw drivers are used, to determine the effects of i) the location and orientation of work objects, and ii) wearing gloves, on ratings of perceived exertion at various body parts. The validity of the psychophysical methodology in determining a preferred work pace was also studied. The subjects drove screws with a screw driver into thick wooden sheet at three vertical and three horizontal locations. They drove serews for 3 minutes at each location and assessed the condition using the psychophysical scale. The results showed that only the vertical location was a significant factor in determining the discomfort ratings. Driving screws at elbow height on the vertical surface and with the lower arm close to the body on the horizontal surface were the work locations with the smallest ratings of perceived discomfort. Wearing gloves had significant effects on reducing the pain of the hand. From the experiment in which a comfortable work pace was identified using 20 minute psychophysical adjustment, it was found that the psychophysical method is sensitive to workers perception of the physical stress when the upper limbs are employed. This was confirmend by the high correlation between the psychophysical results and EMG measurement.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.151-157
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• 1996

Postural tremor of the upper arm in a static posture was measured to provide guidelines of hand tool weight. Three types of camera recording postures were selected. Postural tremor was measured on five levels of tool weights; no weight, 400g, 800, 1200g, and 1600g. For each conditions, upper arm postural tremor was measured together with EMG of biceps, deltoid, and pectoralis major, and Borg's CR-20 scale ratings of perceived exertion. Results of the experiment are as follows; Frequency analysis of tremor revealed that increased amplitude of frequency band of 2-4Hz and 10-14Hz was observed. Postural tremor of the upper arm maintained the initial level until fatigue developed. After the development of fatigue, the rate of the change of postural tremor was significantly increased. Different tool weights and hand postures showed different rate of tremor increase. And time to fatigue and the corresponding endurance time was positively correlated with Borg's RPF scores.

• Journal of the Ergonomics Society of Korea
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• v.13 no.2
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• pp.49-55
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• 1994

It is not difficult to find risky manual material handling which requires various arm exertion for moving and assembling irregular stuffs in industries. Many of workers have been hurt on their muscular and skeletal system due to the manual material handling. This study is to provide data for isokinetic muscular strength elbow flexors and extensors of Korean male and female adults. Provided standard data for isokinetic muscular strength of elbow flexous and extensors can be used for scientific and systematic analysis of arm exertionl.

• Journal of Chest Surgery
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• v.23 no.4
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• pp.758-763
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• 1990

A congenital fistulous communication between the coronary artery and the cardiac chamber or the pulmonary artery is a rare condition, but increasing cases with this anomaly are being recognized with wide spread use of cardiac catheterization and coronary arteriography. Recently we experienced one case of right coronary artery fistula which was associated with atrial septal defect. The patient was a 24 year old female who was admitted because of cardiac murmur, palpitation and dyspnea on exertion after pregnancy. Cardiac catheterization and selective coronary arteriography revealed that a fistulous communication, forming a large aneurysm, was noted from the right coronary artery emptied into the right ventricle. On the operation field, the right coronary artery was curved and markedly dilated from the aorta to the middle segment at acute margin of the right ventricle. The egg-sized aneurysm of dilated right coronary artery was noticed on right ventricle. The aneurysm was incised longitudinally and both the proximal opening and the termination site of the fistula were closed directly with aneurysmectomy. The right atrium was also opened to evaluate the fistulous termination site and repaired only small interatrial septal defect. Postoperative course was uneventful and she was discharged without problems

• Journal of Chest Surgery
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• v.22 no.1
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• pp.116-122
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• 1989

During 22-year period ending in June 1988, operation was performed on 22 patients with primary heart tumor at Yonsei University College of Medicine. Mean age was 38.8*3.03[mean \ulcornerEM] ranging from 14 to 63 years old. Twenty cases were myxomas. Others were fibromyxoma and rhabdomyosarcoma. All patients complained of dyspnea on exertion. Nine cases had palpitation. Other constitutional symptoms were weight loss [7 cases], headache [4 cases], generalized edema [3 cases] and cough [3 cases]. Five cases had neurological symptoms and signs preoperatively. Preoperative NYHA Class was poor [Class II; 8 cases, III; 9 cases and IV; 5 cases]. The most common site of tumor origin was fossa ovalis limbus [16 cases; 72.8%]. Because of severe mitral regurgitation and of recurrent myxoma, 2 cases were reoperated for mitral valve replacement. Postoperative complications were postoperative mitral regurgitation [5 cases; 22.8%] and arrhythmia [4 cases; 18.2%], one of which was supra-His bundle block. All patient survived operation. Follow-up of 15 patients [mean 28.95*8.3 months] was good as functional class 1[8 cases] or II [7 cases]. More effective adjuvant therapy will be necessary to improve long-term prognosis for malignant primary heart tumor.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.136-142
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• 2000

One of the major requirements in preventing Work-related MusculoSkeletal Disorders(WMSDs) is to know definitely what vigorous exertion requirements are contained in a job. This requires improved job analysis tools which can accurately evaluate potentially harmful stresses to the musculoskeletal system. But to simply evaluate the level of stress at a joint, or in a muscle is not enough to motivate job changes. Therefore, the development of ergonomic evaluation tools for the jobs are important to ergonomics. The main objective is compared of the results that made by the ergonomic evaluation tools (e.g., BRIEF and RULA) in actually shoes manufacturing. These were developed in the foreign. So, it is priory needed to research of the ergonomics about Korean characteristic work by physiology and biomechanics.

• Journal of the Korean Society of Safety
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• v.13 no.1
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• pp.147-154
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• 1998

The objective of this study was to evaluate quantitatively the effects of handle types of garden tools on the ergonomic effectiveness, user satisfaction in terms of work performance, and subjective judgment of tactile feel and control. The approach was to compare garden tools with conventional wood handle and newly developed fiberglass handle, and to utilize three different tools: shovel, rake, and hoe. The hollow fiberglass handle was 12% more efficient than either the wood or solid fiberglass handle. The next important measure was the subjective ratings of the perceived exertion averaged across three different tools. The average ratings for the hollow fiberglass handle were the smallest. In conclusion, the hollow fiberglass handle showed better efficiency and better subjective acceptability for comfort, tactile feel, and especially decreased slipperiness.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.641-642
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• 2006

The purpose of this work is to investigate the effect of work load on heart rate variability (HRV) which is widely used marker of the autonomic nervous system activity. Average heart rate, rating of perceived exertion, and the power spectrum of heart rate variability were investigated in seven healthy males during exercise at various work loads. The subjects were divided into two groups according to the average heart rate during exercise, group 1 with lower heart rate and group 2 with higher heart rate. HF component showed decrease followed by increase with workload. Accordingly, the LF/HF ratio showed increase followed by decrease with workload. The peak in LF/HF ratio of group 1 was at the lower workload than that of group 2.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.183-190
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• 1979

A 23-year-old male patient complained dyspnea on exertion and orthopnea since December 1977. On examination, he was tall and slender. There was grade IV/VI to-and-fro murmur on the left sternal border especially on Erb`s point. The liver was descended 2 fingers breadth below right costal margin. There were no signs of Marfan`s syndrome. Echocardiography demonstrated partial closure of aortic valve and dilated aortic root with enlargement of ascending aorta. Left heart cardiac catheterization revealed moderately elevated pulmonary wedge pressure and right ventricular pressure. The left ventricular end diastolic pressure was markedly elevated to 26 mmHg. On aortography, the aortic regurgitation was severe and it was belonged to angiographically Grade IV. The aortic valve was replaced with Carpentier-Edwards valve without excision and replacement of ascending aorta, under the impression of rheumatic valvular heart disease. After closure of aortotomy, blood pressure was transiently elevated and bleeding from the site of inserting air vent needle of ascending aorta was developed. The bleeding was not controlled by any means. On postmortem microscopic study, the histologic changes were strikingly limited to the ascending aorta from the region of the aortic valve ring.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.215-224
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• 1979

Corrected transposition of great arteries associated with dextrocardia [I.D.D.] is a very rare congenital cardiac malformation in which the atria and ventricles are in discordant relation, as are the ventricles and great arteries, but the aorta is to the right of the pulmonary artery. A 13 year old male patient who complained cyanosis and dyspnea on exertion for 8 years, was diagnosed as congenitally corrected transposition of great arteries associated with dextrocardia [I.D.D.], large ventricular septal defect, patent foramen ovale and pulmonary stenosis. He was operated on Nov. 22 1978. The ventricular septal defect was closed with Teflon felt and the pulmonary hypoplasia was corrected with Rastelli operation successfully. On 34th postoperative days, complete heart block was occurred and permanent epicardial pacemaker was implanted with good result.