• Fire Science and Engineering
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• v.31 no.4
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• pp.71-79
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• 2017

A rack warehouse with a vertically loading type and high loading density has severe risks and damage during its fire. In this regard, US and Japan strive to minimize the fire spread by applying in-rack sprinkler, horizontal barriers, etc. corresponding to their own rack warehouse but there is no study and policy in Korea. Therefore, a model scale fire test was carried out targeting the standard rack incorporating the national rack warehouse in order to check fire characteristics in ignition points and installation distances of horizontal barriers in this study. As a result of the test, vertical fire spread of about 30% was inhibited by narrowing its installation distance from 2-layer to 1-layer in an ignition condition of the flue space. In addition, as a result of the measurement of the temperature in the upper and lower parts of the horizontal barrier, the temperature distribution showed about 2~4 higher in a condition with an installation of the barrier than that in the condition without the barrier. Consequently, it is likely that the horizontal barrier will help the initial operation of in-rack sprinkler.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.233-235
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• 2007

현재 기존 철송 시스템에 있어서 문제점인 출발지와 목적지 사이 발생하는 복잡한 작업 프로세스(job process)를 간소화하여 철송 운임비감소와 물류운송의 체계 개선 및 활성화에 기여할 수 있는 시스템으로 DMT(Dual Mode Trailer) 시스템을 들 수 있다. 이에 본 기술의 국내적용 및 개발을 위해 기술동향 조사 및 국내 적용시 고려사항, 국내 적용 접합 모델 도출 등 그 기술성을 분석하였다.

• Fire Science and Engineering
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• v.30 no.6
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• pp.84-91
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• 2016

In case of fire, vertically and intensively loaded rack warehouses are faced with a severe status due to the rapid increase in fires. In this regard, there have been trials to prevent fires from spreading by applying fire extinguishing systems, such as ESFR and In-Rack Sprinklers, vertical and horizontal barriers, etc.; however, it is difficult to calculate and design proper fire extinguishing systems caused by various composition conditions, such as the size and loading density of the rack, types of loading commodities, etc. Therefore, in this study, a standard rack was manufactured, incorporating a rack warehouse in Korea by site investigations, surveys, etc. In addition, a full scale fire test was executed to check the fire characteristics depending on the conditions of the ignition points. As a result, the extracted fire spread speed is expected to be utilized as a reference for performance comparisons of the fire extinguishing systems to be developed and applied in the future.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.99-103
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• 2003

The most commonly used method for space management in the industry is development of site plans. These plans outline how to manage material deliveries, staging areas, and crane locations for construction sites in suburban area but not in congested urban areas. This study focuses on how to efficiently manage space for construction facilities on high-rise buildings in congested urban areas where normally space for facilities around a building footprint is not available. The limitations of available horizontal space create a need to explore vertical expansion of facilities. This raises new aspects of vertical facility handling and flow that need to be considered in the facility design problem. The construction facilities layout plan method provides layout planners with a valuable technique to develop efficient sequences of work that optimally defines how to efficiently utilize the construction facilities and minimize the travel of specific facilities effort on multiple-floor buildings. A genetic algorithm-based heuristic will be presented for generating block layouts for multiple-floor la)rout problems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.321-326
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• 2021

This paper presents a technique to minimize damaged wafers during loading. A thin wafer used in solar cells and semiconductors can be damaged easily. This makes it difficult to separate the wafer due to surface tension between the loaded wafers. A technique for minimizing damaged wafers is to supply compressed air to the wafer and simultaneously apply a small horizontal movement mechanism. The main experimental factors used in this study were the supply speed of wafers, the nozzle pressure of the compressed air, and the suction time of a vacuum head. A higher supply speed of the wafer under the same nozzle pressure and lower nozzle pressure under the same supply speed resulted in a higher failure rate. Furthermore, the damage rate, according to the wafer supply speed, was unaffected by the suction time to grip a wafer. The optimal experiment conditions within the experimental range of this study are the wafer supply speed of 600 ea/hr, nozzle air pressure of 0.55 MPa, and suction time of 0.9 sec at the vacuum head. In addition, the technology improved by the repeatability performance tests can minimize the damaged wafer rate.

• Proceedings of the ESK Conference
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• 1997.10a
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• pp.114-119
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• 1997

자동차 내장 설계의 주요 검토 사항으로 거주성, 조작성, 시인/시계성, 승강성, 적재성, 안전성 등 을 들 수 있다. 특히, 승용차의 주행 시 운전자는 주위 환경에서 일어나는 상황의 대부분을 눈을 통해 인식하게 되므로, 주행 중 운전자에게 충분한 시계를 확보해 주는 것이 자동차의 설계에서 중요한 요인 이 된다. 본 연구에서는 시계성을 중심으로 미국의 FMVSS(Federal Motor Vehicle Sfety Standard), 유럽의 EEC(European Economy Community), 한국공업규격 등에서 규정하고있는 시계 요소들을 조사 비교하고, 시계 성 평가의 기준으로 활용한다. 시계성을 평가하기 위해 전방가시거리, 전방수평시계, Inside Rear View Mirror와 Outside Rear View Mirror를 통해 볼 수 있는 Viewing angle, Inside Rear View Mirror와 95%ile Eyellipse와 높이 등의 요소를 측정하였다. 측정 결과는 승용차의 운전 공간 내의 0ptimal Eye Point를 결 정하는 데 이용되며, 시인/시계성을 개선하는 Seating Packaging Procedure 개발의 기초 자료로 활용될 수 있을 것이다.

• Journal of Navigation and Port Research
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• v.32 no.8
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• pp.629-636
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• 2008

Dual Mode Trailer(DMT) systems are significantly considered as future transportation technique particularly to eliminate complicated job process in the railroad based transportation and reduce relevant logistic cost in economic viewpoint. This paper presents survey of Dual Mode Trailer(DMT) systems in terms of technical applicability in domestic industry, technical trends, etc. We provide several DMT systems addressed until now and propose suitable framework of them to our nation.

• Journal of the Institute of Convergence Signal Processing
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• v.21 no.1
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• pp.21-28
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• 2020

In this paper, a new type of electric wheelbarrow is proposed and developed. The developed electric wheelbarrow is equipped with an attitude reference system(ARS) sensor, which consists of 3-axis acceleration sensor and 2-axis Gyro sensor so that it can estimate pitch angle and roll angle. When an operator tilts the wheelbarrow up and down, the pitch angle is detected. The sign of the pitch angle is interpreted as the operator's intention for moving the wheelbarrow forward or backward and the controller drives the wheel of the wheelbarrow with the velocity according to the magnitude of the detected pitch angle. A cargo box of the wheelbarrow is designed to rotate and is controlled to maintain level always, so an operator can handle the electric wheelbarrow easily and safely. The wheelbarrow consists of an in-wheel motor, a DC motor, motor drives, an ARS sensor considering economical use in industrial field. Three experiments are performed to verify the feasibility and stability of the electric wheelbarrow.

• Journal of the Korean Society of Radiology
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• v.14 no.6
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• pp.733-740
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• 2020

As the use of radiation for medical purposes increases, the exposure dose of medical workers is also increasing. To reduce this dose, various studies on changing the shielding material have been conducted. Recently, a new method to reduce the dose at the entrance of the radiation treatment room was proposed by using the photoelectric effect that occurs when the radiation is scattered. Because this method is particularly effective for low-energy photons, in this study, a slit-type structure was proposed as a excellent shielding structure against scattered x-ray in a general photography room, and was evaluated the shielding effect by Monte Carlo simulation. As a result of the calculation, this study found that in the case of a structure in which steel plates with a thickness of 2 mm and a width of 5 cm are stacked at 2 mm intervals, a shielding effect was approximately 99.9% or more, excluding the heights of the floor and the patient where scattering occurs directly.

• Bulletin of the Society of Naval Architects of Korea
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• v.26 no.1
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• pp.46-62
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• 1989

This paper presents the results of full-scale structural measurements of 4,800 unit pure car carriers "HYUNDAI NO.103" and "HYUNDAI NO.105" on one voyage respectively for each ship, especially in order to investigate the local strength of partial bulkhead above free-board deck. With the measured data, the short-term frequency analyses have been performed. The results show that the wave-induced stresses follow, on the whole, well the Rayleigh distribution. In addition, it has been found from the measured data that transverse local stresses at bulkhead section have a very close relation with the acceleration in athwartship direction. Finally, the long-term analysis has been attempted by using the following two statistical distributions mainly in order to estimate the maximum stress amplitude at the corners of partial bulkhead. 1) Exponential distribution of cycles of stress amplitude 2) Double exponential distribution of extreme values of stress amplitude for each short-term analysis The results of these two cases show a good agreement with each other. For example, the estimated maximum stress amplitude for 10 years at port-side corner of Fr. 132 partial bulkhead is $2125kg/cm^2$ for the first case and $2170kg/cm^2$ for the second case just based on the measured data.