• International Journal of Highway Engineering
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• v.11 no.4
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• pp.9-15
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• 2009

This research presents the structural performance and an improving technique for flexural capacity of road safety facilities based on the damage cases by wind pressure. Among road safety facilities, a support frame of soundproofing walls is considered as a prototype structure and its corresponding structural behaviors and section design are performed mainly by analytical and experimental studies. On the basis of analytical results, glass fiber reinforced polymer(GFRP) with an epoxy matrix which is high stiffness-to-weight ratio was used for applied one of strengthening techniques and their results shows that support frame strengthened by GFRP is the most effective compared to other cases proposed in this research for advancing its flexural improvement, Finally, optimum section design was performed analytically to evaluate wind-resistance capacity and its result would be very useful for developing a practical design guideline for Road safety facilities under strong wind.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.313-316
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• 2000

본 논문에서는 동적 다중경로 환경에 대한 DTV수신 성능 개선을 위하여 정보 데이터 세그먼트 부분에서는 Stop and Go 알고리즘을 사용하고 313 세그먼트 중 한 개만이 훈련열로 쓰이는 기존의 ATSC 표준의 데이터 프레임 구조보다 더 많은 훈련열이 들어있는 새로운 데이터 프레임 구조를 제안한다. 정보가 없는 널 패킷을 훈련열로 대체하기 때문에 데이터의 손실 없이 더 많은 훈련열을 사용하여 특히 동적 다중경로 환경에서 등화기의 수렴 특성을 개선할 수 있다. 전산 모의 실험을 통하여 동적 다중경로 환경의 도플러 천이에 대한 시스템 수신 성능의 개선을 확인하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1998.05a
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• pp.252-257
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• 1998

본 논문은 입력 버퍼링 구조를 갖는 패킷 스위치에서 입력 확장 스위치 패브릭 구조를 통한 성능 개선에 관한 연구이다. 스위치 패브릭의 처리 능력 개선을 위한 다양한 구조에 대한 성능 및 설계 파라메터를 분석하고, 목적지별로 구분되는 입력 확장스위치 패브릭 구조를 제안하고 버스트 트래픽 환경에서 제안된 스위치의 성능을 분석한다.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2010.10a
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• pp.337-340
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• 2010

내화구조는 건축물의 주요 구조부재에 대한 화재안전성을 평가하는 것으로, 국제적으로 내화시험 방법은 실제 건축물과 동일하게 부재에 하중을 가한 상태에서 내화시험을 하도록 ISO 등 국제규격에서는 제시하고 있다. 하지만 국내에서는 건축물의 기둥 및 보에 대하여는 대부분 비재하 시험으로 내화구조를 평가하고 있다. 이는 국제적인 성능평가 방법과도 차이가 있을 뿐만 아니라 실제 건축물 구조부재의 조건과도 차이가 있는 실정이다. 본 연구에서는 내화구조 재하성능평가 기준 개선을 위하여, 국내외 내화성능평가기준에 대하여 고찰하고 이를 통하여 내화구조 인정제도 개선을 위한 기초연구자료를 제시하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.459-460
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• 2009

The purpose of this study is to develop precast concrete structural wall panel that can assure reliable seismic performance. In the previous study, the connection of precast concrete structural wall has some problems in seismic performance. Therefore, this research proposed the precast concrete structural walls which can improve seismic performance. And their seismic performance was verified through lateral loading experiment.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04a
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• pp.22-24
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• 2003

클러스터 구조는 고가용성(high availability)과 결함내성(fault tolerance)을 만족하고 확장성이 뛰어나기 때문에 클러스터 파일 시스템은 멀티미디어 서비스에 적합하다. 사용자 수준 클러스터 파일 시스템［1, 2］은 멀티미디어 서비스에 특화된 기능을 제공하고 저장된 위치에 관계없이 파일이나 디렉토리에 접근할 수 있는 단일 시스템 이미지(single system image) 기술을 제공하지만 실제 저장된 위치에 따라 접근 시간의 편차가 발생한다. 본 논문에서는 메타 데이터 캐쉬와 시스템 버퍼를 이용한 사용자 수준 클러스터 파일 시스템의 성능 개선 방법을 제안하고 각각에 대하여 성능 개선 정도를 분석한다. 메타 데이터 캐쉬는 자주 참조되는 원격 노드의 메타 정보를 로컬 저장구조에 저장하고 시스템 버퍼는 데이터 블록의 쓰기 성능을 개선할 뿐만 아니라 선반입을 통하여 읽기 성능을 개선할 수 있다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.177-186
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• 2005

The latest concrete structure has showed that the deterioration of durability has been increased by the damage from salt, carbonization, freezing & thawing and the others. Therefore, the measures for the concrete which has deteriorated durability have been taken. Among them, it has been often used that surface treatment which cuts off the deterioration factors of durability by protecting the surface of concrete. However, troubles such as fracture and rupture in the repair layer have been reported as time goes by due to the difference between the organic repair material like epoxy and concrete properties. Researchers have been developing the repair material which can cut off the deterioration factors of durability such as $CO_2$ gas, chloride ion and water by making the formation of concrete elaborate through the reaction with calcium ion when the surface improving agent is coated on the concrete. The main ingredient of that is inorganic substance which is the same as the concrete property. This study was evaluated the surface improving agent for permeability, watertightness, air-permeability, chemical resistance and elution resistance. As a result, it has been reported that the surface improving agent improves watertightness and air-permeability by penetration more than 10mm within concrete. Therefore, it is concluded that the surface improving agent developed in this research prevents deterioration of concrete durability when it is coated on the concrete structure.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.8
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• pp.261-270
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• 2014

As Internet traffic increases recently, much effort has been put on improving the performance of a web server. In addition to hardware side solutions such as replacement by high-end hardware or expansion of the number of servers, there are software side solutions to improve performance. Recent studies on these software side solutions have been actively performed. In this paper, we identify performance degradation problems occurring in a conventional TCP networking reception process and propose a way to solve them. We improve performance by combining three kinds of existing methods for Linux Networking Performance Improvement and two kinds of newly proposed methods in this paper. The three existing methods include 1) an allocation method of a packet flow to a core in a multi-core environment, 2) ITR(Interrupt Throttle Rate) method to control excessive interrupt requests, and 3) sk_buff data structure recycling. The two newly proposed methods are fd data structure recycling and epoll_event data structure recycling. Through experiments in a web server environment, we verify the effect of our two proposed methods and its combination with the three existing methods for performance improvement, respectively. We use three kinds of web servers: a simple web server, Lighttpd generally used in Linux, and Apache. In a simple web server environment, fd data structure recycling and epoll_event data structure recycling bring out performance improvement by about 7 % and 6%, respectively. If they are combined with the three existing methods, performance is improved by up to 40% in total. In a Lighttpd and an Apache web server environment, the combination of five methods brings out performance improvement by up to 36% and 20% in total, respectively.

• Journal of Korean Association for Spatial Structures
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• v.10 no.4
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• pp.49-57
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• 2010

This study is the research appling the representative Displacement-Based Design which is the basic concept of Direct Displacement Based Design proposed by Chopra and Goel to original Reinforced Concrete structure and determining the thickness of retrofit Steel Jacket about the Maximum design ground acceleration, and developing the more improved Algorithm as well as program by the Retrofit Design method and Nonlinear analysis by the Performance design method before and after reinforcement appling the determined retrofit thickness. To predict the target displacement of retrofitted columns, a nonlinear analysis model of reinforced concrete columns has been developed to be based on the nonlinear fiber cross-sectional and segmental analysis model, and the seismic displacement level of retrofitted columns is estimated by two procedures, the direct displacement-based design method and the displacement coefficient method. In examples of seismic retrofit design, the current seismic improved design method gives good results in improvements of displacement levels and displacement ductilities of retrofitted columns.

• Journal of Korean Association for Spatial Structures
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• v.12 no.3
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• pp.63-70
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• 2012

In this study, the displacement-based design concept, the performance by the existing reinforced concerte column and steel reinforced concrete composite column for SRC purchased the maximum design ground acceleration improvement compared to the performance design. SRC have several advantages such as strength enhancement and high ductility. H-beam or steel tubes were used for embedded elements of the SRC composite columns. SRC cross-section for the P-M diagram and analysis on the nominal bending monent SRC designed for composite columns for disparity estimation is presented to the displacement-based seismic design. Performance improvement of the performance-based design performance targets for the design seismic displacement and design criteria for the direct displacement-based design methods and to improve the seismic performance due to the displacement coefficient method is proposed to design. SRC compared with the RC column designed to improve the performance and displacement ductility ratio displacement results in the performance design results showed significantly improved performance.