• Journal of the Ergonomics Society of Korea
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• v.14 no.1
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• pp.91-96
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• 1995

The purpose of this study was two-fold : (1) to investigate the difference between the lifting capacities based on three different ergonomic approaches; a) the biomechanical, b) the physiological, and c) the phsychophysicalo approach, and the 1991 revised NIOSH Equation, and (2) to develop a comprehensive model for deter- mining maximum weight of lift.

• Korean Journal of Human Ecology
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• v.18 no.3
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• pp.793-798
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• 2009

Hair cut is one of the best useful technical tool for hair styling. In this study using the rule of the layers of hair design, balanced for visual art, perceptual ability and form created by the principles of analysis and offer hair cuts and hair design of the representation of regions and even hair design as the basis of a student of Hair Beauty and all the people working in the field can create a variety of hair design puts the purpose to establish a basis. The result of this study can be outline as follows: First, the step line and the movement of the relationship between the law of the layers above and below the length of the same layer techniques, the same consists of a vertical cross-section of the overall round shape of the cut same layer is created and the appropriate volume and movement, the movement of low-layer round a little bit more feeling and expression is used when you want. High-layer used to want to move a lot of light and could see that. Second, the layer of the Law and over direction, lifting, section, the line control. weight control and analyzed by principle and the principle of the process of forming the written form was unknown. Third, hair design, the expansion of the expressive power of the law of the layers, and the section of the over direction depends on the presence of line control to express the length of the outline I had to, lifting the weight to adjust form controls, and the expression of Hair Design will be expanding the width. A hair designer, a layer style to create a zone he thought the law of the first layer formative area To further the reach will be a lot of research, leading up formative aspects of this research thesis do not have missing parts, or as a result of the Beauty of Hair Design and the width of a hair design education in the field can perform to help feed the reference materials that will be.

• Journal of the Korea Safety Management & Science
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• v.11 no.3
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• pp.79-85
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• 2009

In this study, the effects of psychosocial stress (box color and precision demand) on muscle activity were evaluated in laboratory setting. Eight subjects performed sagittally symmetric lifting tasks. Box color (yellow, black), precision demand (yes, no), and box weight (5%MVC, 10%MVC, 15 %MVC) were varied and surface EMG signals from seven muscles(medial deltoid right, biceps brachii right, lateral triceps right, latissimus dorsi right, erector spinae right, external oblique right, internal oblique right) were recorded. EMG signals were band-pass filtered($10{\sim}400\;Hz$), rectified, RMS smoothed and normalized (NEMG). Analysis of variance tests were conducted on the total NEMG (TNEMG: the sum of the seven muscles' NEMGs) and on the individual muscle's NEMGs. Box color had no effect on the TNEMG and on the seven muscles activities(p>0.05). When precision demand was required at the end point of lifts, the mean NEMG showed higher values than no precision demand conditions: TNEMG (14% increase) and medial deltoid(40% increase), biceps brachii(10% increase), lateral triceps(26% increase), latissimus dorsi(25% increase) muscles. Those increases showed more conspicuous as the box weight increased in the muscles of medial deltoid, lateral triceps, and latissimus dorsi.

• Journal of the Korean Professional Engineers Association
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• v.34 no.3
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• pp.64-67
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• 2001

In resent the weight of structure is heavier and bigger than before. Engineers use many heavy equipments to erect buildings and bridges. The heavy equipment is very useful to lift any weight. But most engineers do not know the impact of the weight when the equipment lifts the weight. In this study one researched into the impact of the weight in the crane work which lifts the weight in the construction site. Also along the number of pulley sheave the impact of the weight was researched. From the impact field test the impact coefficient of a single pulley sheave crane was 0.65 and the four pulley sheaves crane was 0.13. The result shows that the impact coefficient of a single pulley crane is more than 5 time of the impact coefficient of the four pulley sheaves crane and that engineers must consider the impact effect of the crane work in the construction site.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.11
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• pp.108-114
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• 2021

In this study, a multivariate function was applied to the genetic algorithm for D-type lugs currently used in shipyards to closely analyze the behavioral form of weight loss without double plates. An optimal lifting lug structure design without attachments is proposed. MATLAB R2016a was used to design features by applying multivariate functions to genetic algorithms. Furthermore, the design was achieved by deriving the optimal shapes of lugs using genetic algorithms. The shapes of the designed lugs were validated for structural bonding using the structural analysis program ANSYS 2020 R2, and a robust design of lugs with no appendages was developed.

• Special Issue of the Society of Naval Architects of Korea
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• 2013.12a
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• pp.8-12
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• 2013

DNV crane criteria are specially designated for the vessel equipped with lifting crane to cover the risk during the crane operation. Based on the DNV crane criteria, the crane performance shall be decided. The weight control has great importance in the management of vessel's design for crane vessel. To evaluate limitation of lightship weight and the effect of design changes sufficiently, the lightship allowable VCG curve was used. The optimization process was carried out for generation of the lightship allowable VCG curve due to the difficulty coming from the characteristic of DNV crane criteria. This paper includes the introduction to the DNV Crane criteria and optimization process for evaluation in aspect of lightship weight and VCG.

• Korean Journal of Applied Biomechanics
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• v.15 no.3
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• pp.143-152
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• 2005

The purpose of this study was to predict the failure or success of the Snatch-lifting trial as a consequence of the stand-up phase simulated in Kane's equation of motion that was effective for the dynamic analysis of multi-segment. This experiment was a case study in which one male athlete (age: 23yrs, height: 154.4cm, weight: 64.5kg) from K University was selected The system of a simulation included a multi-segment system that had one degree of freedom and one generalized coordinate for the shank segment angle. The reference frame was fixed by the Nonlinear Trans formation (NLT) method in order to set up a fixed Cartesian coordinate system in space. A weightlifter lifted a 90kg-barbell that was 75% of subject's maximum lifting capability (120kg). For this study, six cameras (Qualisys Proreflex MCU240s) and two force-plates (Kistler 9286AAs) were used for collecting data. The motion tracks of 11 land markers were attached on the major joints of the body and barbell. The sampling rates of cameras and force-plates were set up 100Hz and 1000Hz, respectively. Data were processed via the Qualisys Track manager (QTM) software. Landmark positions and force-plate amplitudes were simultaneously integrated by Qualisys system The coordinate data were filtered using a fourth-order Butterworth low pass filtering with an estimated optimum cut-off frequency of 9Hz calculated with Andrew & Yu's formula. The input data of the model were derived from experimental data processed in Matlab6.5 and the solution of a model made in Kane's method was solved in Matematica5.0. The conclusions were as follows; 1. The torque motor of the shank with 246Nm from this experiment could lift a maximum barbell weight (158.98kg) which was about 246 times as much as subject's body weight (64.5kg). 2. The torque motor with 166.5 Nm, simulated by angular displacement of the shank matched to the experimental result, could lift a maximum barbell weight (90kg) which was about 1.4 times as much as subject's body weight (64.5kg). 3. Comparing subject's maximum barbell weight (120kg) with a modeling maximum barbell weight (155.51kg) and with an experimental maximum barbell weight (90kg), the differences between these were about +35.7kg and -30kg. These results strongly suggest that if the maximum barbell weight is decided, coaches will be able to provide further knowledge and information to weightlifters for the performance improvement and then prevent injuries from training of weightlifters. It hopes to apply Kane's method to other sports skill as well as weightlifting to simulate its motion in the future study.

• Journal of the Ergonomics Society of Korea
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• v.34 no.3
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• pp.279-291
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• 2015

Objective: The purpose of the study is to evaluate appropriate weight for aged farmers in manually handling livestock feed in bags using ergonomic methods. Background: In the livestock industry in South Korea, despite the trend of aging of labor manpower, heavy items are still manually handled in many farms. In particular, among stockbreeding works, the handling of feed in bags weighing 25~30kg is reported as a cause of frequent injuries and musculoskeletal system diseases. However, studies on the standard for recommended weight allowed considering the physical characteristics of aged farmers older than 60 years with greatly decreased physical strength and muscle strength are insufficient. Method: To evaluate appropriate weight for handling of heavy livestock feed in bags, physical techniques for measuring recognized levels of physical work loads, the NLE (NIOSH lifting equation) a method that is an observation type technique, and an ergonomic modeling technique to predict compressive force imposed on L5/S1 were used. Subjects who participated in the experiment were organized into two groups of males/females with mean age exceeding 60 years, and lifting tasks were evaluated for nine weight levels. Results: Based on the results of psychophysical measurement, females showed a tendency of more drastic increases compared to males when weight was over 19kg. The results of estimation of regression models for the weight, 18.0 kg ($r^2=0.97$) and 15.3kg ($r^2=0.97$) were evaluated as stable load for males and females, respectively. In addition, both the observation type evaluation and ergonomic model evaluation showed stable loads in a range of 15~18kg. Conclusion: Given the results of the study, the weight of the feed in bags currently distributed to farms can become a cause of not only overexertion but also farm work related disasters such as musculoskeletal disorders and safety accidents. Providing livestock feed in bags weighing not more than 19kg for aged farmers is judged desirable, and managerial improvement for this matter is considered necessary. Application: The results of the present study can be utilized as useful data for institutional improvement of the weight of livestock feed in bags.

• Clinics in Shoulder and Elbow
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• v.5 no.2
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• pp.73-80
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• 2002

Purpose: Weight lifting is a good training to control body weight, to correct body shape and to relieve stress. How-ever if the training is continued by inadequate training method and technique, the risks of the shoulder injuries are relatively high. Main Subject: The rotator cuff injury is the most common disorder to wright lifters and often results from the train- ing program of upright row, military press and pectoral deck. The chances of subacromial impingement in these postures are high because the shoulder rotates under the acromion at 90 abduction state. Shoulder instability in weight lifters can develop due to various causes. aepeated microtrauma and excessive abduction and external rotation may result in laxity of the anterior capsular structure, ligament and muscles. Behind the neck and bench press are high risk training postures. Other than those injuries, idiopathic osteolysis of distal clavicle, acromioclavicular separation, pectoralis major muscle rupture, and triceps muscle rupture nay develop. Conclusion: The best treatment option of the shoulder injury to weight lifters is to eliminate the possible risk elements for the weight lifters in training program and to provide proper and prompt treatment as soon as possible.

• Korean Journal of Applied Biomechanics
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• v.14 no.2
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• pp.69-83
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• 2004

The purpose of this study is searching for technical merits and demerits of each weight lifting player through qualitative motion analysis system. Moreover, It is also analysis the repeating the establishment of exercise purpose and studying for the effect of the field adaptation. The subject of this study was five male weight lifting players who have been engaged in Korean Delegation Team. The institution of exercise target was made through two times qualitative analysis and the result of studying for the effect of the field adaptation was produced before offering feedback. Moreover, two time analysis added after offering feedback. All analysis was based on 2-D visual analysis. The results of this study are as follows: 1. Maximal barbell moving speed in starting phase was decreased after offering feedback. This result implies advancement of technical skills after offering feedback. 2. From starting posture to 앉아받기, forward and backward moving distance of hip joint was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 3. In terms of pull phase, forward and backward moving distance of hip and shoulder joint was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 4. In terms of pull phase, the difference of horizontal value of coordinates was decreased after offering feedback in all subjects. This result represents advancement of technical skills after offering feedback. 5. In terms of pull phase, the motion range of hip joint was decreased after offering feedback in three of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them were not variable or narrow decreasing. This result represents that feedback system could not brought tremendous effects. 6. From apex point of barbell to 앉아받기, the difference of barbell height was decreased after offering feedback in three of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them weren't variable or narrow increasing. This result represents that feedback system could not brought tremendous effects. 7. In terms of last-pull phase, the angular velocity of knee joint was increased after offering feedback in four of five subjects and this represents advancement of technical skills after offering feedback. However, the rest of them, only one subject, decreased. This result represents that feedback system could not brought tremendous effects. 8. In terms of last-pull, the conversional tendency of maximal extension to flextion came out all but simultaneously without offering feedback in four of five subjects. This is well-performed technique. Only one subject, however, could not use power effectively because the fact that his maximal extension came out in serial, from ankle to knee and waist means dispersion of power. In addition to, after offering feedback, only one subject made increasing the maximal extension of knee in last-pull and this result represents advancement of skills after offering feedback. However, the rest of them could not make meaningful development after offering feedback. 9. It might be assumed that searching for technical merits and demerits of each weight lifting player through qualitative motion analysis system could improve player's skill.