• 대한산업공학회지
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• 제22권3호
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• pp.337-349
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• 1996

A study was conducted to find the possible relationship between slip distance and dynamic coefficient of friction (DCOF) through the biomechanical study of slips and falls using a broader variety of floors and levels of slipperiness than those used before. Four different floor surfaces covering the full range of floor slipperiness (with and without on oil contaminant) were prepared for ten subjects with each walking at a fixed velocity. The results showed that slip distance and heel velocity had a decreasing trend while stride length had a increasing trend as DCOF increased. The contaminant effect overpowered floor slipperiness effect because a higher DCOF surface with oil contaminant created longer slip distance than the lower DCOF with dry floor. Normal gait pattern and suggested heel velocity (10 to 20 cm/sec) were seen on dry floors but abnormally longer stride length and 5 to 10 times faster heel velocity were found an oily floors. In other words, faster heel velocity (greater than 10 to 20 cm/sec) is recommended to measure DCOF on oily floors because the assumption of normal gait was no longer valid.

• Steel and Composite Structures
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• 제43권3호
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• pp.403-417
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• 2022

Recently, there has been an increasing demand for buildings that allow rapid assembly of construction elements, have ample open space areas and are flexible in their final intended use. Accordingly, researchers have developed new competitive structures in terms of cost and efficiency, such as cold-formed steel and timber composite floors, to satisfy these requirements. Cold-formed steel and timber composite floors are light floors with relatively high stiffness, which allow for longer spans. As a result, they inherently have lower fundamental natural frequency and lower damping. Therefore, they are likely to undergo unwanted vibrations under the action of human activities such as walking. It is also quite expensive and complex to implement vibration control measures on problematic floors. In this study, a finite element model of a composite floor reported in the literature was developed and validated against four-point bending test results. The validated FE model was then utilised to examine the vibration behaviour of the investigated composite floor. Predictions obtained from the numerical model were compared against predictions from analytical formulas reported in the literature. Finally, the influence of various parameters on the vibration behaviour of the composite floor was studied and discussed.

• International journal of advanced smart convergence
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• 제13권3호
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• pp.345-357
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• 2024

High rise hotels are densely populated and have complex ignition sources. Once a fire occurs, it can cause serious casualties and property damage. The impact of a fire is greater on special groups such as the elderly and children who move slowly. At present, research mainly focuses on the impact of high-rise building structures on evacuation consequences, but there is little research on the safety evacuation consequences of elderly and children in high-rise hotels, as well as the behavior of people in groups during the safety evacuation process. Therefore, we propose to use Pathfinder software to simulate three scenarios for the elderly and children in high-rise hotels. Scenario 1 involves arranging the elderly and children on higher floors, Scenario 2 involves arranging them on middle floors, and Scenario 2 involves arranging them on lower floors. We further provide three types of personnel pairing schemes for each scenario, namely: no one pairing, two people pairing, and three people pairing. Through simulation analysis, we found that placing elderly and children with lower mobility on lower floors resulted in the shortest safe evacuation time; The evacuation time for solo actions without companionship is the shortest, followed by two people in groups, and the safety evacuation time for three people in groups is the longest. Our research findings have significant implications for improving the evacuation efficiency of personnel in fire scenarios.

• 국제초고층학회논문집
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• 제10권4호
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• pp.265-283
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• 2021

To ensure that fire induced collapse of a building is prevented it is important to understand the sequence of events that can lead to this event. In this paper, the initiation of collapse mechanisms of generic a multi-storey steel frame subjected to vertical and horizontal travelling fires are analysed computationally by tracking the formation of plastic hinges in the frame and generation of fire induced loads. Both uniform and travelling fires are considered. In total 58 different cases are analysed using finite element software LS-DYNA. For the frame examined with a simple and generic structural arrangement and higher applied fire protection to the columns, the results indicate that collapse mechanisms for singe floor and multiple floor fires can be each split into two main groups. For single floor fires (taking place in the upper floors of the frame (Group S1)), collapse is initiated by the pull-in of external columns when heated beams in end bays go into catenary action. For single floor fires occurring on the lower floors(Group S2), failure is initiated (i.e. ultimate strain of the material is exceeded) after the local beam collapse. Failure in both groups for single floor fires is governed by the generation of high loads due to restrained thermal expansion and the loss of material strength. For multiple floor fires with a low number of fire floors (1 to 3) - Group M1, failure is dominated by the loss of material strength and collapse is mainly initiated by the pull-in of external columns. For the cases with a larger number of fire floors (5 to 10) - Group M2, failure is dominated by thermal expansion and collapse is mainly initiated by swaying of the frame to the side of fire origin. The results show that for the investigated frame initiation of collapse mechanisms are affected by the fire type, the number of fire floors, and the location of the fire floor. The findings of this study could be of use to designers of buildings when developing fire protection strategies for steel framed buildings where the potential for a multifloor fire exists.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.631-636
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• 2002

It is common in multistory flat-plate structures that newly cast slabs are supported by a number of previously cast floors. Then the weight of newly cast slabs is imposed on shored previously cast floors as load, and this load may be large as double as dead load. Because early-age construction loads cause large immediate deflection and creep deflection with cracks, this loads influence long-term behavior of slabs. In current provision, the minimum thickness is required to satisfy serviceability But this minimum thickness based on historical precedent is determined by span length, therefore the minimum thickness of current provision can not includes properly the effect of construction scheme including the number of shored floors and construction cycle. In the present study, a minimum thickness criterion, which includes the effect of concrete strength, geometry of slabs and construction scheme, was developed from computer-based iteration using deflection calculation procedure of current code method.

• 한국전자통신학회논문지
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• 제9권10호
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• pp.1111-1116
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• 2014

본 논문에서는, LDPC 코드의 성능을 향상시키기 위해서, LDPC 코드의 에러 플로어(error floors)를 낮추어서 복호를 수행하는 효율 좋은 알고리듬을 제안한다. 이 방법은, 바람직하지 않은 구조 때문인데, Tanner 그래프의 트래핑 세트를 줄여서 복호를 하는 방법이다. 이 알고리듬은 트래핑 세트를 줄이는 방법으로 복호의 효율성을 얻는다. 모의시험을 통해서 이 알고리듬의 개선된 성능을 확인 할 수 있었다.

• 한국산업융합학회 논문집
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• 제15권1호
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• pp.29-36
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• 2012

Reinforced concrete shear walls and X-type steel braces were applied in seismic retrofit techniques for seismic performance evaluation of school buildings constructed in accordance with standard design announced by the ordinance of the ministry of construction in 1980s. Seismic performance evaluation was based on FEMA 356 using response spectrum as elastic analysis and conducted to pushover analysis with nonlinear static analysis. The maximum displacement ratio between floors in 4th and 3rd floors of the existing school buildings was less than 1.0%, which was functioning level in FEMA 356. However, because plastic hinge occurs somewhat in structural members according to the results of pushover analysis, partial reinforcement will be required. X-direction of the maximum lateral displacement of reinforced concrete shear walls than X-type steel braces was 45% and 32% in 4th and 3rd floors of school buildings, and Y-direction was 18% and 17%, respectively.

• Smart Structures and Systems
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• 제12권6호
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• pp.641-659
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• 2013

In this paper is studied the influence of the uncertain mass distribution over the floors on the choice of the optimal parameters of a hybrid control system for tall buildings subjected to wind load. In particular, an optimization procedure is developed for the robust design of a hybrid control system that is based on an enhanced Monte Carlo simulation technique and the genetic algorithm. The large computational effort inherent in the use of a MC-based procedure is reduced by the employment of the Latin Hypercube Sampling. With reference to a tall building modeled as a multi degrees of freedom system, several numerical analyses are carried out varying the parameters influencing the floors' masses, like the coefficient of variation of the distribution and the correlation between the floors' masses. The procedure allows to obtain optimal designs of the control system that are robust with respect to the uncertainties on the distribution of the dead and live loads.

• 한국주거학회논문집
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• 제3권2호
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• pp.13-19
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• 1992

The purpose of this study is to grasp spatial effects of colours in interior design. The visual feeling in the 1/10 living room scale models that are different in the colour combination of ceilings, walls and floors is judged using a semantic scale of the fifteen adjectives. The major findings are as follows; 1) As a result of factor analysis, three dimensions, "evaluation", "activity" and "warmness" are extracted. Dimension 1, "evaluation", is most greatly affected by the chroma and hue of the room colour, dimension 2, "activity", by the hue and value, by the difference in hue and value of ceilings, walls and floors, dimensions 3, "warmness", by mainly the hue of the rooms. 2) Concerning the spatial effects of colour, the subjects felt higher vlaue with relevance to the hue of GY, Y, low chroma and high value. The room colours other than walls is felt more comfortable in similar colour, especially hue and value.re comfortable in similar colour, especially hue and value.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.967-972
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• 2003

In recent years building floors has become larger and more spacious due to the development of new design methods and high strength and light weight materials. However, such long span floor systems may provide smaller amount of damping and have longer period so that they would be more vulnerable to the floor vibration. This study attempts to evaluate the performance of the floors in typical apartment buildings. Four different floors with the area of 43.2$m^2$, 41.44$m^2$, 34.5$m^2$, and 28.89$m^2$ were investigated. The guideline provided by AISC(997) and human perception level of Korean people proposed by S. W. Han(2003) are used to check the acceptability of the floor vibration.