• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.751-758
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• 2005

In this study, the Discrete Element Code was applied to the analysis of falling rock blocks. The simulation was performed using the PFC2D computer code. Falling rock blocks should be applied as additional force to each others. The force affect the motion of falling rock blocks. This was used to find out the behavior of each blocks. This study revealed that the DEM can successfully capture the behavior of falling rock blocks.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.472-475
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• 1995

In this paper, we investigate so-called the falling cat problem. It is well known that a cat, when released from an upside down configuration starting from rest, is able to land on her feet without violating angular momentum conservation. This has being an interesting problem for engineers for a long time. We consider a model of a falling cat as connected two rigid columns, which is a nonholonomic system. We design the controller for it, using time- state control form of the model and exact linearization technique. Finally, we test the controller thorough simulation on the model of a falling cat.

• Journal of the Korean Society of Safety
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• v.24 no.3
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• pp.47-53
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• 2009

Road is typically constructed along ridge area of mountain because of topographical and economic reasons. Therefore, road may face lots of open cut slope which can easily cause rock falling. This study evaluates the structural safety of newly developed falling rock protection system which has a roof deck plate. The structural performance under self-weight, snow load and load from falling rock was investigated using a finite element numerical analysis method. From the analysis results, the H-beam space was limited not to exceed 2.2m. The deck plate was also safe under the examined loading condition. A hinge and connection in the system were investigated through detailed numerical modelling and analysis. The results showed that the hinge was safe enough and that the connection should strengthened with appropriate stiffeners.

• Korean Journal of Plant Resources
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• v.7 no.1
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• pp.35-44
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• 1994

The seasonal flower, leaf and fruit color characterlstics of deciduous woody landscape plants were investigated through the field survey in Suwon, Korea from January 1, 1992 toMarch 20, 1993.The results were as follows ;1. There were 12 cases in the combination of leaf spreading, anthesis, deblossom, fruit coloring,fruit falling, fall foliage coloring and leaf falling of deciduous woody landscape plants(163 spe-cies) investigated. And species of the leaf spreading, anthesis, deblossom, fall foliage coloringand leaf falling were 71(43.9%). And species of the leaf spreading, anthesis, deblossom,fruit coloring, fall foliage coloring, leaf falling and fruit falling were 40(24.5% ).2. The total continuing period of the flowering, fall foliage coloring and fruit coloring of decid-uous woody landscape plants(79 species) investigated varied from 2 months to more than 9months. And the species over 3 months below 4 months were 23(29.2%).3. There were 24 cases in the combination of color of flower, fall foliage and fruit of deciduouswoody landscape plants(79 species) investigated. And the species of the white flower, red fall fo-liage and red fruit were 16(20.3% ).

• Journal of the Korean Society of Safety
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• v.3 no.1
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• pp.15-19
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• 1988

The falling ball viscometer has been widely used for measuring the viscosity of the Newtonian fluids because of its simple theory and low cost. The use of the falling ball viscometer for measuring the non-Newtonian viscosity has been of interest to rheologists for some years. The analysis of the experimental results in a falling ball viscometer rest on Stokes law which yields the terminal velocity for a sphere moving through an infinite medium of fluids. An attempt to use the falling ball viscometer to measure the non-Newtonian viscosity in the intermediate shear rate ranEe was sucessfully accomplished by combining the direct experimental obserbations with a simple analytical model for the average shear-stress and shear rate at, the surface of a sphere. In the experiments with highly viscoelastic polyacrylamide solutions the terminal velocity was observed to be dependent on the time interval between the dropping of successive balls. The time-dependent phenomenon was used to determine characteristic diffusion times of the concentrated solutions of polyacrylamide.

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.46-53
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• 2020

The domestic construction industry is becoming larger, high-rise and specialized. However, safety consciousness is still staying in low levels and falling accidents are apt to rise compared to other industries. So, the new way of safety management is required for reducing of the construction falling accidents. In this paper, we evaluate appropriateness of safety management on construction sites utilizing USN using smart safery equipment. Thus, we calculate loss costs of falling accidents considering accident rates and costs of the USN using smart safery equipment installation then compare both calculated costs. This research aims to propose the method for reduction of construction accidents in addition to conventional safety control methods by analyzing the propriety of applying USN using smart safery equipment on construction sites.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2291-2296
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• 2007

Thermal transport from vertical heated surface to falling liquid film in a channel has been investigated experimentally. Air-flow is introduced into channel to make a counter flow against falling liquid film. This problem is of particular interest in the design of direct contact heat exchange system, such as cooling tower, evaporative cooling system, absorption cooling system, and distillation system. The effects of channel width and air flow rate on the heat transfer to falling liquid film are studied in detail. The results obtained indicate that heat transfer rate is gradually decreased with an increase in the channel width without air flow as well as with air flow in a channel. It is also found that heat transfer rate of air-flow is increased while heat transfer rate of falling liquid film is decreased with an increase in the air flow rate at a given channel width. However, total heat transfer rate form the heated surface is increased as the air flow rate is increased.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.5
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• pp.335-341
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• 2008

Thermal transport from vertical heated surface to falling liquid film in a channel has been investigated experimentally. Air-flow is introduced into channel to make a counter flow against falling liquid film. This problem is of particular interest in the design of direct contact heat exchange system, such as cooling tower, evaporative cooling system, absorption cooling system, and distillation system. The effects of channel width and air flow rate on the heat transfer to falling liquid film are studied in detail. The results obtained indicate that heat transfer rate is gradually decreased with an increase in the channel width without air flow as well as with air flow in a channel. It is also found that heat transfer rate of air-flow is increased while heat transfer rate of falling liquid film is decreased with an increase in the air flow rate at a given channel width. However, total heat transfer rate from the heated surface is increased as the air flow rate is increased.

• Health Policy and Management
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• v.32 no.1
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• pp.21-28
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• 2022

Background: To investigate the association between regular physical exercise and falling experience for 2 years and fear of falling (FOF) in Korean middle-aged and elderly population. Methods: Data from the Korean Longitudinal Study on Aging was used and 3,871 participants who exercised regularly were included at 2006 and follow-up until 2018. An analysis was performed to investigate the association between exercise (exercise time per week and duration) and falls (experience over past 2 years and FOF) using the generalized estimating equation model. Results: Compared to those who exercised more than 5 hours a week (reference group), those who exercised less than 3 hours were more likely to experience falls and FOF (odds ratio [OR], 1.334; 95% confidence interval [CI], 1.059-1.682; OR, 1.218; 95% CI, 1.119-1.326, respectively). Compared to the group who exercised for more than 5 years, those who exercised for less than 1 year were more likely to experience FOF (OR, 1.310; 95% CI, 1.162-1.478). Conclusion: This study showed that there was a negative relationship between physical exercise time and falling experience and FOF in Korean 45 years or more community-dwelling adults. Based on these results, physical activity can be expected to have a positive effect on fall prevention, which implies the need for policy and research on long-term physical activity programs.

• Journal of Korean Academic Society of Home Health Care Nursing
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• v.30 no.1
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• pp.96-104
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• 2023

Purpose: This study aimed to investigate the influence of fall risk, fear of falling, and social support on older inpatients' fall prevention behaviors. Methods: The participants were 105 older inpatients. Data were analyzed using descriptive statistics, independent t-test, One-way ANOVA, Pearson's correlation coefficients, and multiple regression analysis using the SPSS program. Results: The mean fall risk, fear of falling, social support, and all prevention behaviors were 58.05±28.27, 2.47±0.67, 3.58±0.63, and 2.93±0.48, respectively. There were significant differences in fall prevention behaviors by sex, and fall related to education experience. Fall prevention behaviors were associated with fall risk, and fear of falling. The factors influencing the fall prevention behaviors of the older inpatients were sex, fall related to educational experience, fall risk, and fear of falling. It was found that 21% could explain fall prevention behaviors. Conclusion: The results indicate a need to develop a fall prevention education program, including intervention, to reduce the fear of falling among older inpatients.