• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.5-8
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• 2006

In this study, various fundamental experiments including durability and time-dependent deformation are performed to compile a database for a utilization of high-strength concrete for PSC bridges. In the mix design, concrete strength at early age when prestressing forces are introduced to the PSC member and slumpflow suitable for pumping of concrete are considered to make a concrete fit for PSC bridges. The main parameters investigated are the kinds and replacement ratios of mineral admixtures and low-heat cement. Experimental tests on durability include penetration of chloride ions, freezing-thawing, combined deterioration, and simple adiabatic temperature rise test. In addition, time-dependent deformation such as creep, drying and autogenous shrinkage, which is particularly important factor in the design and construction of PSC bridges, is tested and analyzed.

• Proceedings of the Korea Database Society Conference
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• 2001.11a
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• pp.536-554
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• 2001

인터넷 이용자의 증가와 멀티미디어 등 대용량 콘텐츠에 대한 수요의 증가로 인해 데이터 트래픽은 기하 급수적으로 늘어나는 데 비해 네트웍 성능향상에 대한 투자는 이에 미치지 못함으로서 결과적으로 인터넷은 트래픽의 병목현상, 즉 정체현상이 발생하게 되었으며 점차 그 정도가 심해지고 있다. 이 문제를 해결하기 위해 제안하는 방안이 바로 전략적 CDN(Content Delivery Network) 이다. 현실적으로, 본 연구는 물리적인 망 증설만으로는 트래픽 체증 문제를 해결하기는 어려우므로 주요 ISP 네트웍에 전략적 캐시서버를 설치하여 CP의 콘텐츠를 각 ISP 네트웍마다 분산하여 저장하고 이용자의 요청 시 이용자의 인터넷 회선이 물려 있는 ISP 네트웍에서 바로 콘텐츠를 전송하여 데이터 손실과 속도 저하 등의 문제를 해결하는 CDN의 구성과 그 효과를 실증적으로 밝혔다.

• The Journal of Information Technology and Database
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• v.8 no.2
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• pp.41-60
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• 2001

Despite the growth in Internet users, demand for multi-medial, large data files and resulting explosive growth in data traffic, there has been lack of investment in Middle-Mile, interconnection of various networks, resulting in bottleneck effect, which is acerbating. One strategy to overcome such network bottleneck is Content Delivery Network (CDN). CDN does not achieve efficient delivery of large file data through physical improvement/increase in network capacity, but by delivering large file contents, the cause of bottlenecks, from distributed servers. Since it is impracticable to physically improve networks capacity to accommodate the growth in internet traffic, CON, by strong CPs contents at cache servers deployed at major ISPs networks, is able to deliver requested contents to the requesting Web clients without the loss of data and long latency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.5
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• pp.931-936
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• 2009

Classification problem plays a major role in grouping of the records in database systems, detection of faults in VLSI circuits, image processing, and so on. In this paper, we propose the algorithm constructing D1-MACA as a two-class classifier with minimum memory for given pattern sets using the concepts of subspace. Also we analyze the condition that is designed a two-class classifier D1-MACA with two attractors.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.239-240
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• 2010

This study make samples of fiber into a variable condition with strain-hardening cement composite(SHCC) and evaluate the mechanical properties, results from experiment can be used to construction of database for development and application of SHCC.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.04a
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• pp.305-312
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• 2003

Recently, with a progressive development of hardware of computer, the internet and network technology, the environment of construction varies rapidly due to increase the complex form in structure shape and system. With variations, the CAD system for design and products also varies from 2D system to 3D system. This study mainly deals with the methodology of automatic connection design of 3D CAD system, steel connection system (XSteel) using macro. First, using design program in the steel connection system, Xsteel, the joint connection macro will be made up and established the detail classes of design. The next, Database Program (Converter Program) related to the general structural analysis program (MIDAS) and the steel connection program (Xsteel) is constructed for data interface between two programs. From this study, if the merits of 3D CAD system and converter program are utilized well, it is expected that the time needed in modeling and the amounts due to material loses decrease gradually.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.508-513
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• 2006

In construction of RC buildings, the quality of shop and detail drawings is very essential for the quality and safety of buildings. Nevertheless, most of thess works are left to site workers and the requirements about bar detailing such as anchorage and splice have been done without rational design and engineering. The purpose of this research is to develop a computer-aided drawing system of rebars for RC buildings. The system is based on an integrated structural design system, that is SDP. SDP manages an engineering database for structural design information. It provides all the information needed to draw rebar drawings. The drawing system consists of three modules, 1) Structual Plan Drawing System, 2) Shop Drawing System, and 3) Detail Drawing System. It is expected that not only the productivity of detail drawing works but also the quality and safety of buildings will be improved using the rebar drawing system developed in this research.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.574-580
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• 2005

Recently, the number of bridges and tunnels in railway is increasing due to the super high-speedy of train. Also, because of successively accidents of civil structures such as bridges and dams, the importance of maintenance become influential. The purpose of this study is to show the probabilistic life cycle cost analysis technique(PLCC) of the railroad bridge as pubic-infrastructures, and reasonably to indicate the economy in life cycle cost(LCC) through a case study. Rationally for life cycle cost analysis, the data gathered through many materials considered the uncertainty such as covariance. As a result, it is indicated that prestressed concrete bridge is pretty more cost-effective during life-cycle than preflex as well as steel box bridge. In future, if the construction of database and maintenance materials for railroad infrastructure is actualized, the life cycle cost analysis for railroad can be conducted easily and practically.

• Journal of the Korean Society for Railway
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• v.3 no.3
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• pp.139-146
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• 2000

Recently, many kinds of research have been actively developing for a standardization and information to the field of design, construction, supervision, maintenance and management on facilities. The establishment of standard classification system on tunnel facilities and inspection data is most important among the things to have a efficiently maintenance and management. This paper suggests standard classification system on tunnel facilities and inspection data, and, on the basis of that, code work with standard classification system and input work was practised. The purpose of this paper is to suggest a kind of statistics data and investigate a characteristics of inspection using statistic data on railway tunnel.

• Journal of Korea Spatial Information System Society
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• v.2 no.1 s.3
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• pp.83-90
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• 2000

According to the development of Internet system recently, we focused in GIS data distribution and applications via internet rather than GIS data construction. Therefore in this paper, we present the necessity of security policy on GTS data. So we analyze the actual condition of GIS data through expert poll. We classify all of data used in GIS with the three security level : high level, middle level, low level. Finally we propose the proper security method on GIS data transfer and on GIS database access in accordance with progree of PKI project.