• KIEAE Journal
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• 제7권2호
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• pp.39-46
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• 2007

A high-rise building construction in Korea has some problems in engineering, construction and management technologies although the high-rise building construction is recently booming. In addition, the lack of skilled construction labors is increasing, so the development for methods is needed to reduce the labors by prefabrication and mechanization. A re-bar work is one of very important works with regard to cost and schedule management in the high-rise building construction. Nevertheless, the re-bar work has some problems that it is needed many re-bars for joints linking and much time for lifting due to high-rise buildings, and it is difficult to level the skill of labors. So, in this study, the pre-fabrication of three-story height in column re-bars is proposed and the results of an implementation are analyzed and explored by a case study. As the results of case study, the pre-fabrication of three-story heights in column re-bars could reduce the cost in the re-bar work and accelerate the time in the structural frame work. In addition, the pre-fabrication of three-story height in column re-bars could solve the problems such as the waste of many re-bars for joints linking, and the lack of the skilled labors.

• 환경위생공학
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• 제21권4호
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• pp.19-28
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• 2006

The purpose of this study was to investigate the related factor for the prevalence of musculoskeletal symptoms among 212 sewing worker. The survey was performed with self-administered questionnaire for the risk factors related to musculoskeletal disorders(MSDs) from August 5 to 7 in 2005. The prevalence of musculoskeletal symptoms were 75.8% and the those of the local symptoms were 71.7 % for shoulder, 60.4 % for neck, 35.8 % for arm and 50.9 % for wrist. The risk factors related the self-reported MSDs had not shown in general characteristics. But, there was a significant difference between daily working hour and wrist, working speed and neck, the degree of satisfaction and wrist for work related factor. Also, it was shown the significant difference between chair height and neck, the height of sewing machine and wrist among the space below work station, neck, waist for the prevalence of musculoskeletal symptoms. The significant correlation was shown for daily working hour and wrist, working speed and arm, work load and shoulder and the degree of satisfaction and arm for work related subjective symptom. Considering above results, it is suggested the ergonomic design be provided to working hour, the height of chair and work station as well as daily working hour even there is a significant difference for the prevalence of symptoms in each body part for sewing workers.

• KSTLE International Journal
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• 제3권2호
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• pp.114-118
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• 2002

In this work, head-disk interactions are studied when flying height becomes lower than laser bump height on the landing zone of a disk. With the reduction of the spinning speed in a spin stand, the flying height is decreased under the height of laser bumps. Conventional and padded pico sliders sweep between landing Bone and data zone and, then, the dynamic behavior of the pico sliders and head-disk impacts are investigated using AE and stiction/friction signals. After 200n cycle-sweep tests, bearing analysis and AFM analysis indicate that there are some signs of wear and plastic deformation in the landing zone of a disk, although AE and stiction/friction signals are not significantly changed during the sweep tests. The experimental results of this paper suggest that in CSS tests at component level, more rigorous examination methods of wear and plastic deformation might be necessary as flying height becomes getting lower.

• Tribology and Lubricants
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• 제16권4호
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• pp.247-252
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• 2000

As the demand for higher areal recording densities requires a lower flying height of the slider, the variation of the flying height of the slider during drive operation becomes of great concern. The variation of the flying height is closely related with the slider design parameters such as air bearing shape, cavity depth, shallow step depth, crown, camber, pitch offset, roll offset, gram load, and so on. The objective of this work is to optimize the cavity depth and the shallow step depth, which are the control factors in air bearing design, using Robust Design method. It was found that the shallow step depth was statistically significant in affecting the variation of flying height, therefore the level of the shallow step depth should be chosen to minimize the variation of flying height.

• 한국의류학회지
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• 제11권2호
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• pp.13-21
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• 1987

Nowadays, the amount used carpets are on the increase, according to the improvement of life-style. The pleasantness of carpet is caused by the properties of pile, because the most carpets are made pile fabric. For that reason, a study on the compressional properties of carpet is very important issue. This study has been carried out to investigate the differences of compressional properties in various acrylic carpets which were Cut, Tufted, Jacquard and Shag. Each acrylic carpets was transformed to 4, 6, 8 mm of pile height, as results of transformation, we could get the pressure-thickness curve and pressure-deformation curve. The results are summarized as follows. 1. Rate of compression increases, compressive resistance and compressive elasticity decr-eases, as pile height increases. 2. Regardless of pile height, compressive elasticity reached the limit in recovery period at about 10 minutes. 3. Work of compression increases, as pile height increases. 4. Work of compression decreases, as apparent density increases. 5, Cut-type carpet has the best cushion.

• 한국안전학회지
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• 제16권2호
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• pp.80-84
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• 2001

Work stress and health are very important factors related to workers' condition and work safety, Author has conducted a couple of tests to check up three people's pulses before they work during their work for three types of safety guard in construction site. Work type, age, weight, sex experience year, ambient temperature n recorded as variables in this study. These are checked and asked by the author directly, before their pulse check Also, workers' Pulses were measured at height H-0 and H-9.0m to understand psychological the degree of psychological nervousness degree. POLAR protrainer NVTM HRM system(wrist recorder and sensor) was used for the site test. There are three(3) different types of construction safety guard which have been used for, this study. They are usually or frequently used and found in the site. Four different ranges of age groups(20's, 30's 40's, 50's) carpenters are assisted to the test sites with wearing pulse recorder and sensor respectively. All three types of safety guards have the same height 90㎝ even though they are different types. On top of five(5) stories tublar framed scaffolding is fabricated, similar to the one in site, where those safety guards are installed. The older(=more experienced) the workers are the more stable they are. it is shown. Also, It is verified the visually uncomfortable rail type can cause workers to psychologically be unstable.

• 대한인간공학회지
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• 제25권3호
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• pp.17-24
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• 2006

In this paper, we propose a stress analysis on foot by lifting task attitudes. Maximum force and peak pressure were measured on 8 body regions by Pedar system in order to analysis the stress which is affected by task style and angle on foot when Manual Materials Handling task. As for the peak pressure of the whole foot as to the task height during the lifting task, the height from Knuckle to Shoulder was the least in the peak pressure. Also, as for the maximum force and the peak pressure of the whole foot as to the task angle during the lifting task, it could be seen that the more an angle increases, the stress influencing on a foot jumps. As for the maximum force and the peak pressure by foot region as to the task height in case of the lifting task, the height from Knuckle to Shoulder is indicated the smallest value in the maximum force and the peak pressure, thus there is necessary to attain the work design that considered this. Also, as for the maximum force by foot region as to the task angle in case of the lifting task, 0° tasking is indicated to be least, thus there is necessity to be attained the tasking design in a bid to prevent the existence of an angle. The results of this paper are thought to be helpful to the suitable work design, to the prevention of musculoskeletal disorders related to the lower limbs, and to the design of ergonomic safety shoes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.157-157
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• 2008

As the minimum feature size of semiconductor devices scales down to nano-scale regime, ultra shallow junction is highly necessary to suppress short channel effect. At the same time, Ni-silicide has attracted a lot of attention because silicide can improve device performance by reducing the parasitic resistance of source/drain region. Recently, further improvement of device performance by reducing silicide to source/drain region or tuning the work function of silicide closer to the band edge has been studied extensively. Rare earth elements, such as Er and Yb, and Pd or Pt elements are interesting for n-type and p-type devices, respectively, because work function of those materials is closer to the conduction and valance band, respectively. In this paper, we increased the work function between Ni-silicide and source/drain by using Pd stacked structure (Pd/Ni/TiN) for high performance PMOSFET. We demonstrated that it is possible to control the barrier height of Ni-silicide by adjusting the thickness of Pd layer. Therefore, the Ni-silicide using the Pd stacked structure could be applied for high performance PMOSFET.

• 한국운동역학회지
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• 제23권2호
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• pp.159-167
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• 2013

The purpose of this study was to evaluate the gender differences on gait pattern and the kinetics on lower extremities according to the different gait speed. Ten collegiate male students (age : $23.80{\pm}2.94$ yrs, height : $179.40{\pm}5.04$ cm, weight : $66.57{\pm}5.64$ kg) and ten female students (age : $23.40{\pm}2.91$ yrs, height : $166.06{\pm}5.61$ cm, weight : $53.76{\pm}2.75$ kg) participated in this study. To investigate the role, the ratio of the use, and the effectiveness of each joint during gait, we examined the joint work and the contribution to total work. The results of this study were as follows: First, gait pattern was not differ between male and female, hip joint ROM increased with the increase of gait speed both male and female. Second, the eccentric work of the ankle joint decreased with the increase of the gait speed both male and female, on the other hand increased on the knee joint. Third, in the result of the contribution to total eccentric work, male in both the two gait speed was the biggest on the hips joint. However, female in normal gait speed was the greatest on the ankle joint, was the most on the knee joint in the fast gait speed. Forth, the concentric work on the ankle and hip joint increased with the increase of gait speed both male and female. Fifth, in the result of the contribution to total concentric work, there is no difference in the male both the two gait speed, however decreased in the female on the knee joint with the increase of the gait speed, on the other hand increased on the ankle joint.

• 한국과학교육학회지
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• 제4권1호
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• pp.15-25
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• 1984

The purpose of this study is to develop a practical and ideal model of science laboratory enrolled 48-60 students by studying optimal facilities such as laboratory tables and chairs proper to elementary school settings. The science laboratory model was figured out in terms of the following six procedures; (1) Current status as well as problems of science laboratory and its facilities was identified by means of the questionnaires conducted to 201 elementary schools, using stratified cluster sampling tehnique, under the consideration of the school size and the regional characteristics across the country. (2) Collected were the anthropometric data with respect to sitting height, popliteal height, buttock popliteal length, elbow rest height, and back width from the 747 students, 4th-6th grade, in Seoul area. (3) It was measured the work apace necessary for individual student to perform his experiment. (4) Using the data of the process (2), we determined the optimal sizes of laboratory tables and chairs fitted for Korean elementary school students. (5) The optimal area of science laboratory for 48-60 students is determined in terms of the data obtained in (3) for individual work space in addition to the appropriate table size figured out by (4). (6) A practical and ideal model for a science laboratory in elementary school was designed according to the above procedures. For the optimal model of science laboratory, the results of this study can be summarized as follows: The sizes of chair and table are categorized into three groups such as small, medium, and large depending on students' physical outfit. The small size base on the 12.5th percentile point of students' sitting height is used for students of the 0-25th percentile ranks. The medium size base on the 50th percentile point of students' sitting height is used for students of the 26-75th percentile ranks. The large size base on the 87.5th percentile point of students' sitting height is used for students of the 76-100th percentile ranks. (1) Sizes of chairs: The small size is 28cm in width and 33cm in height. The medium size is 31cm in width and 36cm in height. The large size is 35cm in width and 38cm in height. (2) Sizes of laboratory tables: The small size is 120cm in length, 86cm in width, and 60cm in height. The large size is 120cm in length, 86cm in width, and 60cm in height. The large size is 120cm in length, 86cm in width, and 65cm in height. (3) Size of science laboratory: The optimal science laboratory for 48-60 elementary school students, which can install the 12 laboratory tables, is 12m in length and 10m in width.