• The Korean Journal of Physiology
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• 제14권1호
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• pp.31-39
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• 1980

Changes in cardiac performances were observed under variations of the arterial and/or venous pressures with K-loading or K-depletion in turtle heart. Hearts were perfused with turtle Ringer-Locke's solutions containing various levels of potassium ion concentration. When venous pressure increased from 4 to 12 cm $H_2O$, cardiac output increased from $6.2{\pm}0.68$ to $15.7{\pm}0.75\;ml/min$, concomittantly. On the contrary, cardiac output decreased during the elevation of arterial pressure. Stroke work increased more prominently during the arterial pressure elevation than during the elevation of venous pressure. During K-depletion$(1{\sim}2mEq/L)$, cardiac output increased to two times that of normal K-concentration$(3{\sim}6\;mEq/L)$ group. Heart rate increased also, but less markedly. In K-loaded$(7{\sim}8\;mEq/L)$ group, both the cardiac output and heart rate decreased but stroke volume rather increased, because heart rate decrement was disproportionate to that of cardiac output. We concluded that in perfused turtle heart, cardiac output variation was more sensitive to K_depletion whereas heart rate to K-loading.

• 대한한방소아과학회지
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• 제21권1호
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• pp.173-187
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• 2007

Objectives : In order to verify the cardiovascular hemodynamic function of Kammaegdaejo-tang, the experiment was performed in the rats. Methods : Twelve hearts removed from male Sparague-Dawley rats weighing between 250g and 300g were perfused by the Langendorff technique with modified 37 Krebs-Henseleit's buffer solution at a constant perfusion pressure. They were randomly assigned to one of two groups, supplied with either normal saline or Kammaegdaejotang administration. Heart rate, left ventricular pressure, +dp/dt maximum, -dp/dt maximum, and -dp/dt/ +dp/dt ratio were evaluated at baseline after the administration of either normal saline or Kammaegdaejotang. Results : Kammaegdaejotang made the heart rate increasing significantly (p<0.05). Kammaegdaejotang did not effectively work on left ventricular pressure of the isolated heart(p=0.11, no significance). The significant effects of Kammaegdaejotang were observed on +dp/dt max and -dp/dt max(p<0.05). Kammaegdaejotang did not effectively work on -dp/dt/ +dp/dt ratio(p=0.24, no significance).

• 한국정보통신학회논문지
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• 제14권3호
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• pp.723-728
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• 2010

본 연구는 국내의 간호 인력 부족으로 인하여 발생되는 간호 업무 부하를 감소시키기 위해 PPG 신호를 이용한 휴대형 심박수 측정 장치의 설계 방법과 환자의 움직임인 동잡음에서도 신뢰성이 높은 심박수 측정 알고리즘을 제안하였다. 제안된 심박수 측정방법은 생체 신호의 하모닉 특성을 기반한 적응필터로 동잡음을 제거하고 심박수를 측정하는 방법이다. 제안된 기법으로 구현된 심박수 측정기의 성능을 평가하기 위해 손가락 떨림, 손목 움직임 등의 동잡음을 발생시켜 실험하고, 일반적인 방법인 이동평균 필터의 성능과 비교 평가 하였다. 이 실험 결과에서 제안된 기법의 성능이 이동평균 필터의 성능보다 우수한 성능을 보였다. 따라서 본 연구에서 제안한 휴대형 심박수 측정기를 간호업무에 도입한다면, 간호 업무 개선과 보다 선뢰성이 높은 심박수 측정이 가능할 것으로 사료된다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.429-434
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• 2006

It is naturally to be expected that occupational stress on seafarers has specific characters compared to workers engaged in other industries. Because the physical rigors of working and living at sea has been endured as a part of job. The purpose of this paper is to figure out physical changes on seafarers resulted from ordinary shipboard life on the ocean-going cargo vessel. To do this, we performed biochemical inspections testing blood and urine for 28 crews, and measured heart rate of officers engaging in some bridge duties. The tests showed that creatinine, uric acid, total cholesterol, HDL-C, LDL-C of some crews fell down to level which could make a bad impact on human body. And the heart rate of deck officers had vibrated with rather wide amplitude whenever they have got some work-related psychological pressure.

• Annals of Occupational and Environmental Medicine
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• 제35권
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• pp.24.1-24.15
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• 2023

Background: The construction workers are vulnerable to fatigue due to high physical workload. This study aimed to investigate the relationship between overwork and heart rate in construction workers and propose a scheme to prevent overwork in advance. Methods: We measured the heart rates of construction workers at a construction site of a residential and commercial complex in Seoul from August to October 2021 and develop an index that monitors overwork in real-time. A total of 66 Korean workers participated in the study, wearing real-time heart rate monitoring equipment. The relative heart rate (RHR) was calculated using the minimum and maximum heart rates, and the maximum acceptable working time (MAWT) was estimated using RHR to calculate the workload. The overwork index (OI) was defined as the cumulative workload evaluated with the MAWT. An appropriate scenario line (PSL) was set as an index that can be compared to the OI to evaluate the degree of overwork in real-time. The excess overwork index (EOI) was evaluated in real-time during work performance using the difference between the OI and the PSL. The EOI value was used to perform receiver operating characteristic (ROC) curve analysis to find the optimal cut-off value for classification of overwork state. Results: Of the 60 participants analyzed, 28 (46.7%) were classified as the overwork group based on their RHR. ROC curve analysis showed that the EOI was a good predictor of overwork, with an area under the curve of 0.824. The optimal cut-off values ranged from 21.8% to 24.0% depending on the method used to determine the cut-off point. Conclusion: The EOI showed promising results as a predictive tool to assess overwork in real-time using heart rate monitoring and calculation through MAWT. Further research is needed to assess physical workload accurately and determine cut-off values across industries.

• 한국농촌생활과학회지
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• 제8권1호
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• pp.1-5
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• 1997

In this study we tried to examine the efficiency of the agricultural convenient tool (put-on-style-stool) by observing subjects'physiological responses. For this we measured subjects' heart rate, oxygen consumption, blood lactate level, mean skin temperature and rectal temperature. The results of this study are as follows; Heart rate was 75$\pm$2 beats/min with the put-on-style-stool and 78$\pm$2 beats/min without it (P＜0.01). Oxygen consumption was 3.88$\pm$1.90 $m\ell$/kg/min with the Put-on-style-stool and 5. 06$\pm$0.40 $m\ell$/kg/min without it (P＜0.05). Blood lactate level was 2.39$\pm$0.64 mmol with the put-on-style-stool and 3.38$\pm$0.45 mmol without it (P＜0.05). Mean skin temperature was lower but rectal temperature was higher with than without the put- on - style - stool (P＜0.05 and P＜0.01 respectively) So, using the put-on-style-stool was evaluated positively in farmer's work.

• Journal of Korean Neurosurgical Society
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• 제63권6호
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• pp.806-813
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• 2020

Objective : Lumbar disc herniation (LDH) is a common disease, and lumbar discectomy (LD) is a common neurosurgical procedure. However, there is little previous data on return to work (RTW) after LD. This study investigated the period until the RTW after LD prospectively. Clinically, the pain state at the time of RTW also checked. RTW failure rate 6 months after surgery also investigated. Methods : Patients with daily/regular jobs undergoing LD between September 2014 and December 2018 were enrolled. Pain was assessed by the Oswestri Disability Index (ODI) and the Numeric Rate Scale (NRS). Employment type was divided into self-employed, regular and contracted. Monthly telephone interviews were conducted to check RTW status and self-estimated work capability after surgery. Results : Sixty-seven patients enrolled in this study. Three patients failed to RTW, and three others resigned within 6 months after surgery. The preoperative NRS and ODI were 7.2±1.2 and 22.1±7.9, respectively. The average time to RTW was 5.1±6.0 weeks. At RTW, NRS was 1.5±1.8 and ODI was 6.3±3.9. Amongst patients that successfully returned to work were 16 self-employed workers, 42 regular employees, and three contracted workers. The time to RTW of self-employed, regular, and contracted workers were 5.9±8.8, 4.2±4.3 and 13.3±2.3 weeks, respectively (p=0.011). Thirty-six of the patients that returned to work self-reported a 22.8±15.6% reduction in work capability at 6 months. Conclusion : RTW may vary depending on the employment status. In this study, we found that while employment type may affect the length to RTW, most patients were able to RTW and >40% of patients reported no loss of work capabilities 6 months postoperatively, hopefully alleviating some patient hesitation towards LD.

• 대한인간공학회지
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• 제2권2호
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• pp.3-10
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• 1983

While three subjects were running on treadmill at five different speeds, their heart beat interval times were measured and analyzed. From the analysis, we discovered some relation- ships between workload and cardiac response, especially cardiac arrhythmia. Using these relationships, a physioligical model for estimating workload was developed. Although pulse rate has been considered as a good measure of physical load, this study shows that it is highly subject dependent and therefore unsuitable for task evalution. It is recommended to use range of heart beat interval times rather than pulse rate in the evaluation of light work.

• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1997년도 춘계학술대회논문집
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• pp.265-269
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• 1997

A series of experiments was carried out while using totally six female subjects in order to evaluate their psycho-physilolgical variations during their work with VDT both subjectively and objectively compared to those of ordinary office type work and speech communication type work. The results led by the experiment were as follows; the effects with data input work on the subjects from the view point of psychological load was larger than those with the ordinary office work. Oral communication between subjects gave the positive effects upon each subjects to reduce their psychological and mental burden.

• 시큐리티연구
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• 제31호
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• pp.7-24
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• 2012

본 연구에서는 경호경비현장에서 이루어지고 있는 실제적인 경호경비원들의 장시간 경계근무 중 발생하는 하는 생체리듬의 변화를 알아보기 위해 K대학교 경호학과 학생 9명을 대상으로 실제 경계근무와 같은 형태로 180분간 경계근무를 실시하였다. 30분 간격으로 HRV(Heart rate variability)를 통하여 심박동 변이도와 자율신경검사를 실시 한 결과 심박동 변이도 HRT과 SDNN은 유의한 차이가 없어 180분간의 경계근무 시간 동안 안정적으로 유지 하였다. 자율신경계의 전체적인 활성정도를 반영하는 TP는 안정시 보다 90분과 120분에 유의(p<.05)한 차이로 높게 나타났다. 또한 120분 이후에는 유의한 감소하여, 120분 이상의 경계근무에서는 자율신경계의 활성도가 감소하는 것으로 나타났다. VLF, LF, HF 모두 유의한 차이는 아니지만 120분에 감소하는 경향을 보여 TP 변화에 영향을 주었다. 교감신경과 부교감신경의 균형도를 나타내는 LF/HF ratio는 경계근무 30분에 유의하게(p<.05)높은 것으로 나타났다. 따라서 경계근무 120분 이후에는 집중력이 감소하는 것으로 사료되며, 경계근무 시작 30분 까지는 근무시작으로 인한 긴장감과 흥분감이 있는 것으로 나타났다.