• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.745-748
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• 2002

Many malfunctions take place in container crane spreader due to impact. So we designed a 2DOF hydraulic impact absorbing system and studied the change of impulse with respect to the variation of falling height and weight. The falling height becomes higher than 1m and the falling weight goes up heavier than 100kg, the impact absorbing rate was lower. When spreader is bumped against container and impulse force concentrates on one point, impact absorbing equipment would not be operated properly and make some trouble.

• 한국레이저가공학회지
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• 제6권1호
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• pp.1-8
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• 2003

A molten metal droplets are deposited onto solid substrate for solid freeform fabrication, Collision dynamic and substrate heat transfer associated with solidification determine the final shape of molten metal droplets. In this study, the experimental model, based on the variational condition with substrate temperature and falling height, was produced reliable optimal data of droplet pattern.

• International journal of advanced smart convergence
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• 제9권2호
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• pp.38-48
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• 2020

The shaking-off the dust from balustrade of higher stories may cause the higher risk of falling accident rate. Main purpose of this study was to quantify an effect of balustrade heights and blanket types on possibility of falling accident relative to one's motor controllability during shaking-off the dust of the blanket from balcony. Female participants, who consisted of total 10 under condition of balustrade height of 3 kinds (90 cm, 110 cm, 130 cm) and blanket types (0.4 kg, 1.6 kg, 3 kg, 200^⁎230 cm), performed repetitively the task of shaking-off the dust of the blanket. Vertical position and velocity of center of mass due to increase of blanket weigh in case of balustrade height of 90 cm was increased, but vertical ground reaction force was decreased swiftly. That is, the higher balustrade height was, the less distance difference between center of mass and center of pressure was.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.517-520
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• 2003

The snow-fatting measurement system including the snow sensor applying the photo-coupler is investigated in this study and using this snow sensor the height of snow fallen is measured. To measure the snow depth, five photo sensors are arranged with 5 mm distance. The snow-falling measurement system, which is measuring the motor revolution controlled with stepping motor, is mounted above the snow surface. From this work, it is feasible to measure quantitatively the snow on real time. Its software implements a proven method to achieve valid measurements also under difficult conditions as future study. In cases where the snow sensor is applieded to the prediction of snow in the meteorological observation system and the snow removing system, it is recommend the GRS-Option in order to improve the quality of snow measurements for better compensation.

• Journal of Trauma and Injury
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• 제23권2호
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• pp.96-101
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• 2010

Purpose: This study was conducted in order to evaluate the epidemiological characteristics of?children with fall-down injuries according to age groups and to analyze the major trauma groups that were treated at the emergency room (ER). Methods: Among 1,222 children under age 6 who were treated at the ER from January 2008 to December 2009, a retrospective study was conducted through examination of medical records. The children were classified by age into 3 groups: infant, toddler, and pre-schooler. In each group, the differences between the causative factors that led to the fall-down injuries were analyzed. Also, ISS (Injury Severity Score) score above 4 was classified as major trauma, and an ISS score 0-1 was classified as a minor trauma. The relationship between major trauma and age group was also analyzed. Results: Through an analysis of child fall-down injuries, men (56.6%), toddler (47.3%), head-related symptoms (72.9%), furniture-related traumas (80.2%), and falls from less than a 1-m height (69.9%) were found to be common factors. Furthermore, in radiological studies, fractures and brain hemorrhages accounted for 16.9% of major traumas, and simple skull fractures were the most common (21.4%). Distributed according to age group, the factors relevant to fall injuries were fall height and head-related symptoms for infants, accident site, fall height and head-related symptoms for toddlers, and accident site for pre-schoolers (p<0.05). Also, headrelated symptoms and fall height were independent factors of major trauma in all age groups. However, major traumas (17.3%) were related to dumped trauma, fall height and accident site (p<0.05). Conclusion: This study was mainly about head-related injuries, and toddler were most common victims. The relevant factors for the major trauma were falling height for infants, accident site and falling height for toddlers, and accident site, falling height for pre-schoolers.

• 한국컴퓨터정보학회논문지
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• 제17권10호
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• pp.55-60
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• 2012

자유 낙하하는 물체가 받는 힘은 중력뿐이다. 우리는 중력만을 받아서 운동하는 것을 자유 낙하 운동이라고 하고 자유 낙하하는 물체를 자유낙체라 한다. 즉, 자유낙체란 물체의 초기 운동 상태와 무관하게 중력의 영향으로만 자유롭게 낙하하는 물체를 말하는 것이다. 본 논문에서는 공기의 저항을 무시하고, 수직방향으로 짧은 거리의 범위내에서 고도에 의한 자유낙하 가속도의 변화가 없다는 가정을 한다. 이러한 가정 하에서 자동차가 수직 상 방향으로 도약하여 최고점에 도달하는 시간, 최대높이, 자동차가 출발 위치로 돌아오는 시간과 자동차의 속도, 자동차가 땅에 떨어질 때의 시간 및 속도에 대해 알 수 있다. 이는 텔레매틱스에서 자동차나 오토바이가 도약하는 정도와 사고의 위험을 측정할 수 있다.

• 대한안전경영과학회지
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• 제14권3호
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• pp.49-57
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• 2012

Proportion of falling from height accident at construction work accounts for more than 40%, and the number of injuries is getting increased. So without considering falling from height, we can say that it's hard to achieve our goal(accident prevention). Another critical point that we have to think about theses days is the fact that construction workers are getting older. To be specific, the number of workers who are above 50 years old accounts for 65.6% among the fatalities(2007~2011, KOSHA inspection). Accordingly, to effectively prevent construction accedents, especially falls from height, we need to focus on motion analysis of older construction workers and then make suitable measures for growing accident rates at construction work.

• 한국농공학회논문집
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• 제58권6호
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• pp.39-45
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• 2016

In this paper, analyzes the characteristics of self-weight consolidation on the dredged clay according to the fines content and falling height. Research was performed with the dredged clay sampled by Sae-mangeum field site. Classification of fines content was performed by sieve analysis test. After adjusting the fine content, self-weight consolidation tests were carried out focussing on the variation of fines content and falling heights. From the test results of the self-weight consolidation test, samples with high fines content had reached sedimentation completion more later than ones with less fine content samples. In other words, the start of self-weight consolidation was slowing down with increasing of fines content. Also, from the test results of calculating the coefficient of sedimentation consolidation, the coefficient value were increased with the fines content increases. In addition, the change of sedimentation ratio and volume ratio showed more higher changed value as the fine content increases. Thus, it is important to consider the fines content when estimate the settlement time of dredged soil in field dredge work.

• 한국생산제조학회지
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• 제22권6호
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• pp.963-968
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• 2013

In this study, we carried out a structural analysis for determining the stresses acting on the tempered glass of a freely falling cellular phone using ANSYS 13.0, commercial finite element code. We designed a phone heavier than any contemporary cellular phone and performed finite element analysis using the falling speed at a height of 104 cm, which is equal to of the average leg length of Koreans. By determining the maximum stress acting on the phone's tempered glass and frame, we identified the location of large deformation. Furthermore, we evaluated the maximum/minimum equivalent stress and deformation of the reinforced glass and frame as functions of time.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.54-61
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• 2004

This paper deals with flow characteristics on the air entrainment and the energy dissipation in nappe flow over the stepped drop structure. Nappe flow occurred at low flow rates and for relatively large step height Dominant flow features include an air pocket, a free-falling nappe impact and a subsequent hydraulic jump on the downstream step. Air entrainment occurred from the step edge, through a free-falling nappe impact and a hydraulic jump. Most energy was dissipated by nappe impact and in the downstream hydraulic jump. It was related with the step height and the overflow depth, but not related with step slope. The stepped drop structure was found to be effcient for water treatment and energy dissipation associated with substantial air entrainment.