• 산업경영시스템학회지
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• 제27권3호
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• pp.90-96
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• 2004

The objective of this study was to develop a model for safe work load based on a physiological model of metabolic energy of manual material handling tasks. Fifteen male subjects voluntarily participated in this study. Lifting activities with four different weights, 0, 8, 16, 24kg, and four different working frequencies (2, 5, 8, 11 lifts/min) for a lifting range from floor to the knuckle height of 76cm were considered. Oxygen consumption rates and heart rates were measured during the performance of sixteen different lifting activities. Simplified predictive equations for estimating the oxygen consumption rate and the heart rate were developed. The oxygen consumption rate and the heart rate could be expressed as a function of task variables; frequency and the weight of the load, and a personal variable, body weight, and their interactions. The coefficients of determination ($r^2$) of the model were 0.9777 and 0.9784, respectively, for the oxygen consumption rate and the heart rate. The model of oxygen consumption rate was modified to estimate the work load for the given oxygen consumption rate. The overall absolute percent errors of the validation of this equation for work load with the original data set was 39.03%. The overall absolute percent errors were much larger than this for the two models based on the US population. The models for the oxygen consumption rate and for the work load developed in this study work better than the two models based on the US population. However, without considering the biomechanical approach, the developed model for the work load and the two US models are not recommended to estimate the work loads for low frequent lifting activities.

• 국제학술발표논문집
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• The 9th International Conference on Construction Engineering and Project Management
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• pp.632-639
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• 2022

The objective of this study is to analyze the productivity, efficiency, and factors affecting the productivity of a spray task from an international airport project. The study is focused on the productivity analysis of the Subcontractor whose job was to supply and apply sprayed-applied fire-resistive material (SFRM) on steel members to achieve the necessary fire ratings on the building structures of the Hamad International Airport, Qatar. The study analyzed the productivity of the four sprayer teams who completed the task at three locations and three areas of the airport. The study found that the productivity of the individual team observed during the SFRM spray task was not only different but was also observed different when they worked at varying floor heights where different factors affecting productivity were predominant. The study found that the efficiency was lowest (47.32%) when the spray team had to work at second-floor heights and factors affecting productivity such as limited accessibility for material movement and lifting, site congestion, lack of continuity of operation due to priority areas and frequent re-handling of machines and tools were present. Besides, the factors such as adverse weather conditions and sub-trades interference affected productivity at all locations. The findings show that productivity depends on multiple factors and those factors need to be identified and addressed to improve productivity. The findings also show that the estimated efficiency was hard to achieve but possible since Team 4 had 97% efficiency on the first floor of the airport.

• 한국산학기술학회논문지
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• 제13권10호
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• pp.4629-4635
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• 2012

본 연구의 목적은 중량물 들기 작업시 비대칭 무게중심과 상체 옆으로 기울임 여부가 어떻게 L5/S1 주변 허리 근육의 Peak EMG 진폭에 영향을 미치는지를 알아보는 것이다. 요통을 포함한 근골격계질환은 무겁지 않은 물체의 지속적인 반복 취급뿐만 아니라, 일회성의 커다란 부하도 신체 조직의 부담으로 작용하여 발생할 수 있다. 11명의 20대 대학생 남성은 15.8kg의 물체를 들어올리는 Task를 3회 실행하였다. 이 때 대칭 무게중심의 물체를 상체를 기울이지 않고 들어 올리는 경우, 비대칭 무게중심의 물체를 상체를 기울이지 않고 들어 올리는 조건, 그리고 비대칭 무게중심의 물체를 상체를 기울여서 들어 올리는 경우에 따라 6개의 L5/S1 주변의 근육들로부터 Peak EMG 진폭이 수집되어 분석되었다. 결과는 비대칭 무게중심을 지닌 물체 취급시 무게중심에서 먼 쪽의 허리 근육에서 Peak EMG 진폭이 발생하고, 그 진폭의 크기는 대칭 무게중심 물체를 취급하는 경우보다 크게 나타났다. 또한, 비대칭 무게중심의 물체를 취급할 경우 물체나 상체를 물체의 무게중심 방향으로 기울이는 것은 기울이지 않을 때보다 대측성 등근육에서 Peak EMG 진폭 증가시켰다. 이러한 연구 결과는 비대칭 무게중심의 중량물을 들어 올리는 작업에서 요통 발생을 예방하기 위한 행정적인 조치로써 가능하면 상체를 전두면 기준으로 기울이지 않는 작업자 자세 조언이 필요함을 말해준다.

• 한국응급구조학회지
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• 제9권1호
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• pp.43-53
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• 2005

The purpose of this study was to survey a perception of frequency & importance level of job performance, from 249 paramedics who were working at fire station. The job related activities of 4 duties, 18 tasks and 145 task elements were checked by 4 rating scale. The data were analyzed using a SPSS program for descriptive statistics. The results of the study were as follows ; 1. Some of the most frequent tasks were medical tx, managing people & organization, trauma care, pt assessment, general coping skill 2. Some of the most frequent task elements were preparation of written reports, operation of pt lifting supplies, transportation of patients on stretchers, administration of cervical collar and utilization of scoop stretcher. 3. Some of the highest level of importance in task were resuscitation of circulation, surgical tx, safety & infection control, environmental emergency care, trauma care. 4. Some of the highest level of importance in task elements were administration of cervical collar, adult CPR, infant CPR, child CPR, and AED. 5. The highest level of task elements in perception of frequency & importance were administration of cervical collar, infection control after pt care, utilization of long back board, disinfection of ambulance after ride a long, care of chest pain pt, care of unconscious pt, tx of asthma. 6. A difference between frequent & importance score were due to lack of supplies(41%), structural problems(30%) and medical control system(16%), lack of skills(10%), Suggestion; 1. This paper would be more reliable and confirm through wilder range of survey. 2. It would be necessary of more depth survey through dacom study from paramedic. 3. Development of field oriented protocol & curriculum that based on task elements which have high score of both frequency & importance level is required.

• Annals of Rehabilitation Medicine
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• 제42권6호
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• pp.777-787
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• 2018

Objective To examine the long-term effects of the low-frequency repetitive transcranial magnetic stimulation (LF-rTMS) combined with task-specific training on paretic hand function following subacute stroke. Methods Sixteen participants were randomly selected and grouped into two: the experimental group (real LF-rTMS) and the control group (sham LF-rTMS). All the 16 participants were then taken through a 1-hour task-specific training of the paretic hand. The corticospinal excitability (motor evoke potential [MEP] amplitude) of the non-lesioned hemisphere, and the paretic hand performance (Wolf Motor Function Test total movement time [WMFT-TMT]) were evaluated at baseline, after the LF-rTMS, immediately after task-specific training, 1 and 2 weeks after the training. Results Groups comparisons showed a significant difference in the MEP after LF-rTMS and after the training. Compared to the baseline, the MEP of the experimental group significantly decreased after LF-rTMS and after the training and that effect was maintained for 2 weeks. Group comparisons showed significant difference in WMFT-TMT after the training. Only in the experimental group, the WMFT-TMT of the can lifting item significantly reduced compared to the baseline and the effect was sustained for 2 weeks. Conclusion The results of this study established that the improvement in paretic hand after task-specific training was enhanced by LF-rTMS and it persisted for at least 2 weeks.

• 한국안전학회지
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• 제13권4호
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• pp.248-255
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• 1998

The objective of this study is to conduct the prevention method using electromyography that is to resist the strain on L5/S1 disc and to measure the heart rate for the prevention of low back pain during lifting. EMG signals and heart rate were analyzed under the condition of fixed vertical factor (20∼80cm), two horizontal factors (35cm, 55cm), and two weight factors (10kg, 25kg) 2 times per minute for each lifting task. Eight healthy male workers performed nine-step stretching exercises which were intensified back power at the L5/S1 disc for six months. After completion of the two trials, the results were compared. The results of this analysis show that EMG signals have more an effect on the weight than the horizontal factors similar to those analyzed previous study, and are decreased. Therefore, those exercises presented very efficient. Also, there are not statistically significant differences on the analysis result of heart rate between weight factors.

• 대한전기학회논문지:시스템및제어부문D
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• 제55권7호
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• pp.344-351
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• 2006

The fatigue of back muscle in the repetitive lifting motion was studied using multiple parameters(FFT_MDF, RMS, 2C, NT) in this study. Recent developments in the time-frequency analysis procedures to compute the IMDF(instantaneous median frequency) were utilized to overcome the nonstationarity of EMG signal using Cohen-Posch distribution. But the above method has a lot of computation time because of its complexity. So, in this study, FFT_MDF(median frequency estimation based on FFT) algorithm was used for median frequency estimation of back muscle EMG signal during muscle work in uniform velocity portion of lumbar movement. The analysis period of EMG signal was determined by using the run test and lumbar movement angle in dynamic task, such as lifting. Results showed that FFT_MDF algorithm is well suited for the estimation of back muscle fatigue from the view point of computation time. The negative slope of a regression line fitted to the median frequency values of back muscle EMG signal was taken as an indication of muscle fatigue. The slope of muscle fatigueness with FFT_MDF method shows the similarity of 77.8% comparing with CP_MDF(median frequency estimation based on Cohen Posch distribution) method.

• 한국산업정보학회논문지
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• 제6권3호
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• pp.79-86
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• 2001

신종 직업병 중 누적외상성질환(Cumulative Trauma Disorders)은 고도로 분업화된 현대 산업환경에서 주로 수작업을 수행하는 종사자에게 발생된다. 본 연구는 단순반복근로자의 누적외상성질환에 노출되는 정도를 EMG시스템을 이용하여 분석한 결과는 다음과 같다. AEMG에서는 작업경과에 따라 근피로도는 증가하다가 작업 완료시에는 근피로도가 내화벽돌을 들기 전보다 감소하였다. MF와 MPF에에서는 천극근, 다열근의 근피로도가 많은 것으로 나타났다. ZCR에서는 모든 내화벽돌의 무게에서 작업전과 작업후의 근피로도가 가장 낮게 나타났다. 종합적으로 작업진행이 계속됨에 따라 근육피로도는 증가하고 있었고, 단순반복운반작업시에 천극근과 다열관에 대한 근피로도가 큰 것으로 나타났다.

• 대한물리의학회지
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• 제15권3호
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• pp.29-41
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• 2020

PURPOSE: The aim of this study was to provide evidence for the treatment of Forward Head and Rounded Shoulder Posture (FHRSP) using posture correction exercises by comparing muscle activity and onset time around the neck and shoulder area during an arm elevation task. METHODS: The subjects were divided into FHRSP (21 persons) and non-FHRSP (19 persons) groups to measure muscle activity and onset time of muscle contraction. Wireless surface electromyography was used to assess the muscle activity and onset time of the right and left sternocleidomastoid (SCM), splenius capitis, anterior deltoid, middle deltoid, serratus anterior, upper trapezius, pectoralis major, and infraspinatus during an arm elevation task. After the pre-measurement, the participants performed the postural correction exercises, and then the post-measurement was conducted. RESULTS: After the posture correction exercises, there were significant differences in the muscle activity and onset time of all muscles in the FHRSP group. The results of the comparison of the muscle onset time during an arm elevation task demonstrated that after the postural correction exercises, the muscle onset time was significantly reduced in the right and left SCM and left splenius capitis, but there were no significant changes in the onset time of other muscles. CONCLUSION: The results of this study help us understand the change in muscle activities and muscle contraction onset time in a person with FHRSP when lifting the arm and suggest the relevant basis to apply the posture correction exercise in clinical settings.

• 로봇학회논문지
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• 제12권4호
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• pp.441-447
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• 2017

Robot arms are being increasingly used in various fields with special attention given to unmanned systems. In this research, we developed a high payload dual-arm robot, in which the forearm module is replaceable to meet the assigned task, such as object handling or lifting humans in a rescue operation. With each forearm module specialized for an assigned task (e.g. safety for rescue and redundant joints for object handling task), the robot can conduct various tasks more effectively than could be done previously. In this paper, the design of the high payload dual-arm robot with replaceable forearm function is described in detail. Two forearms are developed here. Each of forearm has quite a different goal. One of the forearms is specialized for human rescue in human familiar flat aspect and compliance parts. Other is for general heavy objects, more than 30 kg, handling with high degree of freedom more than 7.