• Korean Journal of Construction Engineering and Management
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• v.1 no.1 s.1
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• pp.35-44
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• 2000

The major objective of construction process control(CPC) is to provide construction managers with operational information that will help reduce project duration and save project cost. However, the CPC in Korea is being applied to construction projects with some basic problems such as the inconvenience of CPC S/Ws and the process control unconcerned with construction information classification system and computer system to integrate cost and schedule. This study analyzes the present condition of CPC including the basic problems, and then suggests the reform measures in technical and operational viewpoints to reduce construction risk. The focus of study is on the technical improvement for the application of construction information management system applicable to both cost estimating and schedule management.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.2
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• pp.169-180
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• 1998

This research presents development of real-time service primitive in MHS(Message Hanling system) supporting desk-top conferencing system. Desk-top conferencing system is one of the real-time GC(Group Communication) services. The complexity of modem society has led to the consequent need for real-time GC between a number of people in order to jointly handle tasks in business, government and other forms of organization. Despite the many different form of desk-top conferencing systems developed to date, there are still few systems in widespred no. One of the biggest hurdle preventing the widespred adoption of real-time GC is the lack of agreement on user-friendly interchange environments. In distributed office environments, the MHS is one of the most widely used service for information interchange. It is a standard of electronic mail system which is concerned mostly with asynchronous exchange of short notes. It is clear that additional functions on MHS are necessary in order to allow users to properly process their real-time group messages and provide them with important facilities as a communication infrastructure for real-time GC.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.3
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• pp.1-8
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• 2017

An experimental study is needed a reinforcing method for seismic load to apply for RC structures because a lot of earthquakes have frequently happened in the world and those also collapsed infrastructures or damaged human lives. The reinforcing effect of PolyUrea (PU) appeared to be excellent under blast and impact about RC structures. In this study, Stiff Type PolyUrea (STPU) had developed by manipulating the ratio of the components of prepolymer and hardener of PU. And the durability performance evaluation of STPU for deterioration and chemical resistance has been performed. Acid environmental exposure test and ultraviolet (UV) exposure test have been performed as the durability performance evaluation for STPU. Concrete carbonation exposure test and freezing and thawing test for concrete coated with STPU have been performed. The experimental result showed that STPU has high resisting capacity and durability in all tests. Therefore, STPU would be used as seismic reinforcement materials.

• School Mathematics
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• v.18 no.2
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• pp.323-348
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• 2016

The 2009 revised national mathematics curriculum have inserted mathematical 'linking cube' activities in the 6th grade math classes to improve students' spatial problem solving abilities and communication skills. However, we found that it was hard for teachers to teach problem solving and communication skills due to the absence of mathematical way of representing linking cubes in the classroom. In this paper, we propose 3D 'turtle representation system' as teaching and learning tools for linking cube activities. After using turtle representation system for linking cube activities, teachers responded that turtle representation system is a valuable problem solving and communication tools for the linking cube mathematics classes. We conclude that turtle representation system is a well designed teaching and learning tools for linking cube activities, and there are lots of educational meanings in the 3D turtle representation system.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.23-30
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• 2008

UHPC has high performance, high strength and excellent mechanical properties. Moreover UHPC(Ultra High Performance Cementitious Composite) has advantage to reduce cross section under the same load compared with other kinds of concrete. But silica fume which is imported from foreign country has a abundant portion in UHPC mixture in comparison with normal concrete. This is one of the main reason to raise the construction cost. Superior mechanical properties of UHPC due to the optimum filling composition can be changed by replacing the very fine ingredient. The purpose of this research is to grasp the characteristic of UHPC which silica fume and silica flour is replaced with limestone powder. This experiment can be divided into three classes according to the kinds of replacement. The compressive strength and flow of all types were measured and microstructure and hydration phenomena for comparing RPC were analyzed by SEM, XRD, NMR method. As a result, the replacement can be considered to be effective by for the decrease of the UHPC structure construction cost and improvement of the fresh UHPC.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2004.05b
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• pp.229-233
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• 2004

According as internet and Information-Communication technology develop with the fast speed, Electronic Catalog that is used B2B or B2C electronic commerce is important element middle who can express well special quality of corporation's goods and product most effectively from internet space. But, several problems that creation of Electronic Catalog and standard absence about application that can say as importance technology base in electronic commerce and market newcomers who is constructing each other dissimilar system and take part in electronic commercial transaction can not use Electronic Catalog information exchange and transaction are happening. So that this treatise can use Electronic Catalog document that user who define Electronic Catalog document structure that can process information of goods configurationally and takes part in transaction is defined in electronic commerce hereupon, integration style Electronic Catalog system design and embody. This system did useful information that can not get from various advantage and catalog document such as business all-in-one and interoperability in different environment that Web Services through interlock with Web Services has so that can get Web Services.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.59-67
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• 2016

Concrete is a very useful construction material for the sealing disposal of hazardous substances. In general, mass concrete is applied to these structures. And, the mineral admixtures are recommended for the long term performance. Calcium leaching could be happened due to the contact with pure water in underground structures. Thus, it is needed to evaluate the resistance of calcium leaching for concrete mixed with mineral admixtures. From the test results, the mineral admixtures are effective to the improvement of long term compressive strength and chloride diffusion coefficient in concrete members. When calcium leaching is happened, however, the reduction of compressive strength and chloride penetration resistance is severe than OPC case, the micro pore distribution is adversely affected. Consequently, when the mineral admixtures are applied to underground structures which is exposed to calcium leaching environment, it is desirable to reduce water-to-binder ratio, to expose after the sufficient pozolanic reaction, and to use BFS than FA.

• Land and Housing Review
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• v.2 no.4
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• pp.569-575
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• 2011

In domestic mechanical demolition work against RC building, unsuitable selection and loading of heavy equipment have led to occasional accidents such as collapse of structural members during the work. Therefore, proper analysis technique to easily decide allowable equipment load on the structure is needed at the planning stage of mechanical demolition work. In this paper, performing loading test and elastic analysis against 4-story building at full scale, we confirm appropriateness for allowable load of equipment on RC structures, which was suggested in previous study, and suggest structural analysis method that can evaluate safety of RC building during the mechanical demolition. The suggested method can be effectively utilized to improve work efficiency through safety of mechanical demolition work against RC building and proper management of equipments.

• Korean Journal of Social Welfare Studies
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• v.48 no.2
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• pp.303-329
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• 2017

This study aimed to explore the trajectories of computer game use of school age children and to identify the related predictors. The data for this study used Korean Children and Youth Panel data covering from the second year to the sixth year of elementary school. A total of 1,959 participants were analyzed. Latent class growth model was employed to explore the trajectories of computer game use and multinomial logistic regression was conducted to identify the significant predictors. Main results indicated that three types of trajectories were identified: low game using group, high initial using-fluctuating group, and high increasing game using group. Each group was found to be associated deferentially with sex, aggression, attention deficit, main caregiver's education, siblings, parent absence after-school, neglecting, family income, family trip, school grades, and peer relationship. Based on these findings, this study emphasized the importance of predictive intervention for the game user among early school age children and suggested useful practical strategies.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.370-370
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• 2017

최근 기후변화와 이상기후의 영향으로 인하여 홍수재해의 시 공간적 패턴은 보다 복잡해지고, 예측이 어려워지고 있다. 이러한 기상이변에 따른 홍수피해를 예방하기 위한 비구조적 대책으로 홍수위험등급 및 범람범위 등의 정보를 포함하고 있는 홍수위험지도의 작성이 필요하다. 실제로 고정밀도 홍수위험지도를 작성하기 위해서는 지형, 지질, 기상 등의 디지털 정보 및 사회 경제와 관련된 다양한 DB를 필요로 하며, 강우-유출-범람해석 모델링을 통해 범람면적 및 침수깊이 등의 정보를 획득하게 된다. 하지만 일부지역, 특히 개발도상국에서는 이러한 계측 홍수 데이터가 부족하거나 획득할 수가 없어 홍수위험지도 제작이 불가능하거나 그 정확도가 매우 낮은 실정이다. 따라서 본 연구에서는 ASTER 또는 SRTM과 같은 범용 DEM 등 지형자료만을 기반으로 한 선형이진분류법(Liner binary classifiers)과 ROC분석(Receiver Operation Characteristics)을 이용하여 미계측 유역 (DB부재 또는 부족으로 강우-유출-범람해석 모델링이 불가능한 북한지역)의 홍수위험지역을 탐지하고, 적용성을 평가하고자 한다. 5개의 단일 지형학적 지수와 6개의 복합 지형학적 지수를 이용하여 Area Under the Curve (AUC)를 계산하고, Sensitivity (민감도)와 Specificity (특이도)가 가장 높은 지수를 선별하여 홍수위험지도를 작성하고, 실제 홍수범람 영상(2007년 북한 함경남도지역 용흥강 홍수)과 비교 분석하였다. 본 연구에서 제시하는 선형이진분류법과 ROC분석 방법은 홍수범람해석을 위한 다양한 기초정보를 필요로 하지 않고, 지형정보만을 사용하기 때문에 관측 데이터가 없거나 부족한 지역에 대해서 우선적으로 홍수위험지역을 탐지하고, 선별하는데 유용할 것으로 판단된다.