• Proceedings of the ESK Conference
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• 1994.04a
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• pp.105-105
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• 1994

신체 부위를 이용한 Manual Materials handling(MMH) 작업시 무리한 작업하중의 취급으로 인하 여 많은 사고 또는 요통이 발생하기 때문에 작업자의 능력에 맞는 적정 하중에 대한 연구가 필요 하다. MMH작업의 적정하중에관한 연구는 미국 등의 나라에서는 많이 이루어져 왔으나 우리나라에서 는 연구되어 있지 않다. 미국의 경우 NIOSH Guideline을 만들어 MMH시 작업지침으로 활용하고 있으 나 이 지침을 그대로 우리나라에 적용하기에는 신체조건이 달라 우리나라 고유의 연구가 필요하겠다. 적정하중의 연구에는 많은 시간과 경비가 필요하기 때문에 외국의 경우 심리 육체적방법(Psychophysical Method)을 사용하여 시간과 경비를 줄이고도 실제 8시간 작업시의 결과와 비슷한 결과를 얻었다. 본 연구에서는 MMH작업의 적정 하중결정에 있어서 심리육체적 방법을 사용하여 한국인 작업자에 대한 하중과 HIOSH Guideline의 RWL값과의 비교를 하였다. 학생군과 실제 작업자군의 피실험자에 대하여 심리육체적 방법을 적용하여 들기작업을 실험하였다. 6가지 들기 작업을 20분 동안 실시하여 피실험자들이 자신에게 적합하다고 생각하는 적정하중을 측정하였다. 그 결과, 학생군은 RWL값보다 평균 2.5배를, 작업자군은 3.4 배를 적정하중으로 정하였다. 따라서 HIOSH Guideline을 적용한 RWL값은 우리나라 작업자에게는 많은 여유가 있는 하중임을 보여 주었다.

• Journal of the Ergonomics Society of Korea
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• v.16 no.3
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• pp.23-36
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• 1997

The objective of this study was to make a comparison of the oxygen consumption rates during the lifting activities and the physiological criteria of the recommended weights of RWL, AL, and MPL by NIOSH Guideline. The physical Work Capacity (PWC) based on the bicycle ergometer was 2562.71ml/min, and the one based on the treadmill was 2874.89ml/min for the college male students of Korea. Lifting activities with four different lifting frequencies(2, 5, 8, 11 lifts/min) for one lifting range from floor to 76cm height were studied. The oxygen consumption rates and the heart rates were measured or recorded while subjects were lifting the weight of RWL, AL, and MPL. The heart rates and the oxygen consumption rates increased as the frequency increased from 2 to lifts/min. However, those slightly decreased at the frequency of 11 lifts/ min. The measured oxygen consumption rates were ranging from 2.3% to 29.6% higher than the physiological criteria 620, 700, and 1000ml/min, respectively, of the RWL, AL, and MPL for all the lifting frequencies (5, 8, 11 lift/min) except 2 lifts/min. It si suggested that the physiological criteria of NIOSH Guideline should be based on the lifting PWC, which can consider the type of lifting activity and the frequency of the task, rather than using the PWC by ergometer or treadmill. The measured oxygen consumption rates were ranging from 13.26% to 40.11% higher than the values estimated using the models by Garg and Kim. From these findings it is suggested that the NIOSH Equation should not be directly applied to Korean without resonable modifications.

• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.69-75
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• 2009

It is well-known that lifting capacity of a worker is influenced by body posture during the task. When a task analyst make use of RULA and REBA Trunk and upper arm angles are recorded in a separate item. It means that the interaction between the angles of two body segments may be ignored in a final score. The NLE(NIOSH Lifting Equation) has been used to supplement this problem. However, there is no study to validate the result of RWL (Recommended Workload Limit) under the existence of interactions between trunk and upper arm angles. The goal of this study was to assess the effect of the interaction between trunk and upper arm angles. Three responses, including NMVC(normalized maximum voluntary contraction), RWL(Recommended Weight Limit) and subjective judgment in psychophysical method (Borg's scale), were recorded according to the combinations of three trunk angles and nine upper arm angles. The results showed that lifting capacity is highly influenced by interaction of two body segments(trunk and upper arm). It means that the task workload has to be analyzed along with the interaction of trunk angles and upper arm angles when the task analyst assesses potential risk factors on the postures. This study may be able to be a fundamental study to develop an assessment method for lifting task analyses according to body postures.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1669-1675
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• 2018

The present study aimed to investigate rapid weight loss (RWL) and consequent physical and psychological challenges among judo athletes at the national athlete training center in 2017. The following results were obtained. Judo athletes used weight loss methods such as "gradually reduce meal portion," "skip meals," "limit water intake," "wear sweat suit for training," and "use sauna," and had physical and mental distress from such unhealthy weight management practices. Information about weight loss was obtained from "colleagues or senior athletes," "Internet," and "head coach or coach," and not experts such as nutritionists or physicians. Thus, athletes are recommended to employ healthy weight control methods based on advice from experts, such as nutritionists and physicians.

• Journal of Korea Water Resources Association
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• v.34 no.6
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• pp.617-625
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• 2001

Peace dam constructed against the water attack had stopped in the first step, linked with Hwacheon dam through bypass tunnels and had an effect of flood surcharging in its pocket on Hwacheon dam downstream. To study the utility of Peace dam, the flood control effects of Peace dam and the restricted water level (RWL) in Hwacheon dam were reviewed and identified with operating Hwacheon dam system. Analysing the results the ideas of expanding the usability of the water resources in Hwacheon dam system were suggested. To do that, the criteria and the model of reservoir operation were established frist and the optimization of the operation have done. Based on the results the performance of the optimization was evaluated as an reference coefficient with relative value of the registered data to the optimized. And examining several alternatives for the RWL in Hwacheon reservoir operation made more feasible RWL suggested. And its economic benefit was also reckoned.

• Journal of agriculture & life science
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• v.50 no.2
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• pp.73-82
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• 2016

Best drought tolerance index was determined through statistics analysis and growth appearance of drought tolerant plants was determined by cultivation in pot and sloping land. For determination of best drought tolerant indicators, RD(Resistant dry days), LD(Leaf area), UTR(Unit transpiration), RWC(Relative water content), RWL(Relative water loss), LA(Leaf area), SN(Stoma unmber) and SA(Stoma area) were carried out by correlation and PCA analysis. RWL and UTR were affected on plant drought tolerance according to comparison among six indices for resistant dry days. The PCs axes separated SA, LA, RD and RWC and SN. UTR was negatively correlated with SA, RWL were also negatively correlated with RWC and SN. RWL and UTR were proved best selection indicator for the selection of drought tolerant species. Ulmus parvifolia, Bidens bipinnata, Patrinia villosa, Kummerowia striata, Arundinella hirta, Artemisia gmelini etc. were selected drought tolerant plants. Shoot growth appearance of drought resistant plants was differed pot and sloping land. Shoot growth and leaf number was no significant differences between the pot and sloping land. However, root growth of drought tolerant plants was all the difference between two cultivation. T/R ratio of drought tolerant plants was also found a big difference. T/R ratio of drought tolerant plants in sloping land was lower than that of pot. These results will be served efficiently plant breeding.

• Journal of the Korean Society of Safety
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• v.27 no.4
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• pp.96-100
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• 2012

Low back pain (LBP) is a major issue in modern industrialized society which is mainly caused by manual material handling (MMH) tasks. The objective of this study was to provide scientific data for establishing work standard for Korean workers throughout the laboratory experiment including some specific lifting tasks. Thirty male college students were recruited as participants. The maximum voluntary contraction (MVC), recommended weight limit (RWL), and psychophysical safety weight using Borg's CR-10 scale were studied. Results showed that the RWL was 8.4% MVC higher than the proposed psychophysical safety weight. Based on this result, it is suggested that the NIOSH lifting equation (NLE) should not be directly applied to Korean without reasonable modifications. The ratio of psychophysical safety weight to MVC was ranged from 20.1 to 26.4%. It is expected that use of the methodology in this study may provide better expectation of the work ability of Korean for reducing lower back pains caused by MMH.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.11
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• pp.2541-2547
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• 2010

In this paper, we propose a design technique which replaces logic transistors of 1.2V with medium-voltage transistors of 3.3V having small off-leakage current in repetitive block circuits where speed is not an issue, to implement a low-power eFuse OTP memory IP in the stand-by state. In addition, we use dual-port eFuse cells reducing operational current dissipation by reducing capacitances parasitic to RWL (Read word-line) and BL (Bit-line) in the read mode. Furthermore, we propose an equivalent circuit for simulating program power injected to an eFuse from a program voltage. The layout size of the designed 512-bit eFuse OTP memory IP with a 90nm CMOS image sensor process is $342{\mu}m{\times}236{\mu}m$. It is confirmed by measurement experiments on 42 samples with a program voltage of 5V that we get a good result having 97.6 percent of program yield. Also, the minimal operational supply voltage is measured well to be 0.9V.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.687-691
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• 2011

In this paper, we design an 8-bit eSuse OTP (one-time programmable) memory in consideration of EM (electro-migration) and eFuse resistance variation based on a $0.18{\mu}m$ generic process, which is used for an analog trimming application. First, we use an external program voltage to increase the program power applied an eFuse. Secondly, we apply a scheme of precharging BL to VSS prior to RWL (read word line) activation and optimize read NMOS transistors to reduce the read current flowing through a non-programmed cell. Thirdly, we design a sensing margin test circuit with a variable pull-up load out of consideration for the eFuse resistance variation of a programmed eFuse. Finally, we increase program yield of eFuse OTP memory by splitting the length of an eFuse link.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2209-2216
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• 2011

In this paper, we design a 32-bit eFuse OTP memory for PMICs using MagnaChip's $0.18{\mu}m$ process. We solve a problem of an electrical shortage between an eFuse link and the VSS of a p-substrate in programming by placing an n-well under the eFuse link. Also, we propose a WL driver circuit which activates the RWL (read word-line) or WWL (write word-line) of a dual-port eFuse OTP memory cell selectively when a decoded WERP (WL enable for read or program) signal is inputted to the eFuse OTP memory directly. Furthermore, we reduce the layout area of the control circuit by removing a delay chain in the BL precharging circuit. We'can obtain an yield of 100% at a program voltage of 5.5V on 94 manufactured sample dies when measured with memory tester equipment.