• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.3
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• pp.205-213
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• 2003

The primary purpose of this study is to investigate punching shear capacity of flat plate slab using high strength concrete in column. It may be much contributed to economy efficiency and structural advantages that High Strength Concrete(HSC) used for vertical member and Normal Strength Concrete(NSC) for horizontal member. Therefore, six plate flat slab specimens with HSC column and NSC slab had been made and tested with real scale. The major variables were compressive strength of concrete(fck=285, $460kgf/cm^2$), extended length of HSC from column face and amount of shear reinforcements. As the result of this test, the maximum load and punching shear capacity of specimens is affected by extended length and shear reinforcements.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.1
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• pp.89-98
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• 2012

A steel wire-integrated deck plate that welds integrated triangle truss steel wires on a galvanized steel sheet is developed to reduce construction costs of slabs or formworks such as shores and supports, and it is already widely applied in many construction fields. In this research, experimental tests for 14 full scale specimens, which are in the same field conditions, are conducted on several parameters such as the diameter of top, bottom and lattice steel wire, cutting methods of ends. According to the result, changes in final destruction types of the test bodies and cutting methods of ends didn't affect structural performance of test specimens, and for a 4.0m-span test specimen, there was no big problems in using bottom bar D7 or D8.

• Journal of the Korean Geosynthetics Society
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• v.13 no.4
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• pp.11-20
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• 2014

The behaviors and stability of reinforced subgrade with short geogrid were examined and evaluated during construction. First of all, analytical approach for the minimum length of geogrid was performed to guarantee stability during construction loading state. Secondly, the economic aspects for reinforced subgrade were compared with between domestic standards applying with 0.7 H reinforcement length and new way to mix short and long reinforcement. Full scale railroad subgrade was constructed with the size of 5 m high, 6m wide, and 20m long to verify the stability of the subgrade with the length of 0.3 H, 0.35 H, 0.4 H reinforcement. Total 51 sensors were installed to measure settlement, bulging, and the change of stress of the subgrade. It is concluded that the reinforced subgrade with short(0.35H, 35% of height) geogrid had stability within allowable level of deformation and stress increment during construction.

• The Korean Journal of Applied Statistics
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• v.29 no.4
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• pp.559-569
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• 2016

A long-run relationship of stock, monetary, realty markets, and business conditions has been suggested to exist due to internal and external shocks. This study investigates whether such a relationship really exists and then performs statistical tests to discern features of the long-run adjustment processes from short-run discrepancies because it is difficult to find studies that examine the market relationship. The comovement relationship of the whole market does not appear to hold for the entire study period; however, it is found to exist for the period before the financial crisis. Estimated error correction models show consistently declining equilibrium errors each period that suggests a recovering process of the long-run equilibrium from short-run secessions.

• Journal of Korean Society of Steel Construction
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• v.17 no.4 s.77
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• pp.481-490
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• 2005

This paper summarizes the full-scale test results on the CFT column-to-flat plate connections subjected to gravity loading. CFT construction has gained wide acceptance in a relatively short time in domestic building construction practice due to its various structural and construction advantages. Constructing an underground parking floor as a flat plate system is often regarded as essential for both cost savings and rapid construction. Efficient details for CFT-column-to-flat-plate connections have not been proposed yet, however, and their development is urgently needed. Based on some strategies that maximize economical field construction, several connecting schemes were proposed and tested based on a full-scale model. The test results showed that the proposed connection details can exhibit punching shear strength and connection stiffness comparable to or greater than those of their R/C flat plate counterpart.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.629-637
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• 2003

This s paper presented the results of the three phases of fatigue tests to determine the fatigue strength of in-plane welded gusset joints, which are the most common details inevitably existing in the region of high stress range. A total of 57 fatigue specimens with varying thickness and strengths were made and tensile fatigue tests performed. One full-scale beam fatigue test was also performed. The validity of the fatigue strength of those details in the specification was confirmed, with the effects of thickness of flanges and welded attachments, length of attachments, and strength of applied steel examined. The characteristics of crack initiation and propagation were also observed. The test result was evaluated by comparing it with other test data and fatigue criteria of other countries. To determine the degree of stress concentration in the weld toe depending on geometric configuration such as attachment length and transition radius, analyses were performed. Compared to the present specification, analytical results indicate the need to revise and subdivide the detail categories.

• Proceedings of the Technology Innovation Conference
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• 2005.02a
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• pp.124-139
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• 2005

In the early stage, the radio communication industry was widely accepted as a monopoly industry, so it has been controled and managed by government. But the advanced technology in Information and Technology industry has led constant increase of demand and dramatic change of communication market. Furthermore it is expected that frequency resource is to be short by market change due to wire-wireless integration. That is why the effort to utilize and manage limited frequency resource efficiently is being executed around the world. Not only newly developing and allocating the spectrum but also reallocating the existing spectrum important are, since transforming inefficiently used existing spectrum to new service can increase producer's surplus and social welfare. The economic approach to valuate the spectrum and spectrum usage right is necessary different from the traditional cost based approach, and through this approach I expect active transaction of spectrum. In this paper the real option methodology is used for valuation of spectrum, considering spectrum user's option right based on future revenue. In detail, the matter of withdrawing and reallocating the existing analog radio broadcasting spectrum is evaluated in this paper, The digitalization of a broadcasting service is widely spreaded around the world in terms of technology and service utility, and analog TV broadcasting has already been decided to be transformed to digital TV broadcasting. It was planned to convert analog radio broadcasting to DAB service before adopting DMB service, but nowadays this issue is not on the table anymore. However if the increasing demand of digital voice and broadcasting service is considered, this kind of research to valuate a spectrum is needed urgently. The result of this research shows that when the redeployment of spectrum is done, social welfare will increases. The point of the reallocation time and value are suggested by the monte carlo simulation through ROVM. In this paper, I use real option to valuate the spectrum and provide the point of the reallocation time and reasonable guideline, and moreover, the suitable information of this paper is expected to reduce risk and loss in policy practice.

• Proceedings of the Technology Innovation Conference
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• 2005.02a
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• pp.268-286
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• 2005

본 연구에서는 OECD 주요 10개국을 대상으로 국가별 정보통신산업의 성장 추이를 각각 분석하고 국별 특성을 비교하는데 목적이 있다. 이를 바탕으로 각국의 정보통신산업이 경기순환 또는 단계별 발전 속성을 지니고 있는지를 파악하고 국가별 공통점과 특이점을 분석하고자 하였다. 방법론적으로 OECD 국가들의 정보통신산업 GDP 추이 및 성장률의 움직임을 국면전환 (regime change) 확산과정으로 묘사함으로써 각 국가별 정보통신산업 발전 양상의 특징 및 국면전환 시점 등을 포착해 내고자 하였다 추세를 갖는 대표적 확산과정인 GBM 모형과 평균회귀 성향을 갖는 대표적 확산과정인 Vasicek 모형에 각각 마코프 국면전환을 도입하여 국가별 정보통신산업 GDP 및 GDP 성장률의 추이에 있어 국면 전환 여부와 독특한 발전 특성을 비교 분석하였다. 실증분석 결과 정보통신산업 GDP의 성장률과 변동성 사이에는 높은 상관관계가 있었으며, 한국, 멕시코 등은 고성장, 고변동성을, 미국, 프랑스, 일본 등은 저성장, 저변동성의 특성을 보이는 것으로 나타났다 또한 한국의 경우 유일하게 성장률과 변동성 모두 국면전환이 일어나는 국가로 나타났다. 장기평균 성장률의 특성에 따라 분류한 결과, 한국, 일본, 미국, 멕시코, 뉴질랜드는 고성장에서 저성장으로의 국면전환, 핀란드와 덴마크는 경기 순환적 국면전환, 노르웨이, 프랑스, 캐나다는 단일 국면으로 분류할 수 있었다. 특히 한국의 경우 평균회귀 속도와 변동성이 타 국가에 비해 높은 특성을 보여주었다. 본 연구는 정보통신산업을 미시적 분석이나 세부 항목별 정량적 분석을 통해서가 아니라 산업의 발전 속성 및 경기 순환 등의 관점에서 분석함으로써 정보통신산업 정책의 수립 및 집행을 거시적 안목 하에 정립할 수 있게 한다는 데 의의를 가진다. 또한 경제변수를 묘사하는데 있어 국면전환 확산과정을 사용함으로써 향후 실물옵션 등을 통한 기술 및 무형자산의 가치평가에 있어 기초자산의 움직임을 보다 정확히 포착해 낼 수 있는 프로세스를 제공하였다는데 또 다른 의의를 갖는다고 하겠다.

• Fire Science and Engineering
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• v.19 no.4 s.60
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• pp.32-36
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• 2005

A water mist system was considered as a possible alternative to a gaseous suppression system that can not prevent re-ignition after fire extinguishment for a power transformer room. This study deals with the fire suppression capability of the water mist systems. High-and low-pressure water mist systems were examined to compare efficiency of both systems. The power transformer examined in this study occupied about $7\%$ of a $10m\times10m\times$ transformer room. Full-scale suppression tests were performed for six different fire scenarios: two spray fires, three pool fires and one cascade fire. The fire suppression test results demonstrated that the high-pressure system was superior to the low-pressure system, especially considering oxygen depletion and the ambient temperature distribution.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.742-752
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• 2017

The bridge type of steel concrete composite rahmen or pre-flex has been applied where a lower depth girder is required due to vertical clearance restrictions caused by the crossing of rivers and roads. On the other hand, because these types are not only complicated to manufacture and construct, but also expensive, void slab bridges may be an alternative. In this study, prefabricated PSC-I shape girder was used to make a void slab and all procedures for bridge development, such as analysis, design, fabrication, and real-scale test, were included in the scope of research. The results of this study will provide sufficient background data to be applied to the field and the structural safety has been verified through experiments.