• Proceedings of the Korean Society for Cognitive Science Conference
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• 2000.05a
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• pp.137-142
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• 2000

본 논문에서는 확률적 자연언어 처리에서 중요한 문제인 자료 희귀(data sparseness)의 어려움을 해결하는 새로운 방법으로 차원 축소 모델을 제시한다. 세 가지의 세부 방법이 제안되었으며 Katz의 back-off 방법의 성능을 최저로 했을 때에 비해 약 60%정도의 성능이 향상되었다. 현재까지 최고의 성능을 보이고 있는 유사도 기반의 방법에 비해서도 약 5∼20%의 성능이 향상되었다. 따라서 차원 축소 모델은 확률 추정의 새로운 방법으로 쓰일 수 있다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.1
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• pp.55-63
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• 2013

In this study, seismic performance was evaluated considering the deterioration level for the low-rise and moderate buildings with non-seismic details which are most common in Korea. Evaluation results showed that the deterioration condition is relatively good even after 24 years of construction but the seismic performance did not satisfy the protection index in the first and second evaluation. In case of the third evaluation, the goal performance was satisfied based on the interstory drift ratio but reinforcement is found to be necessary. Seismic performance was evaluated after the target buildings were reinforced in the walls, bracing, and damper. Results showed the interstory drift ratio drastically reduced regardless of reinforcement methods and satisfied the level of immediate occupancy. In case of wall reinforcement, however, base shear increased more than double which requires review on the existing foundation.

• Journal of Korean Society of Steel Construction
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• v.19 no.4
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• pp.425-434
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• 2007

The SC (steel-concrete) composite column was developed to take advantage of the relative economy of using concrete as opposed to steel in carrying large compressive forces. As the SC composite column is pre-fabricated, its use can minimize laborand can speed up the erection of a steel building. In this study, an experiment was conducted to analyze the influence of several parameters, such as the load ratio, the concrete ratio of an area, and its performance with or without fire protection, on the performance of the SC composite column. This paper proposes that the calculation of the strength reduction ratios of columns be done by increasing the temperature. Theoretical equations were used to evaluate the effectiveness of the fire resistance of the SC composite column, and the results of the test and analysis were compared. The fire resistance of the SC composite column was increased by decreasing its load ratio, but the concrete ratio of an area has minimal influence on the fire resistance of the SC composite column.

• 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.

• Fire Science and Engineering
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• v.24 no.6
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• pp.104-111
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• 2010

The strength of steel in a concrete filled steel tube (CFT) is reduced in a fire, but the concrete filled structurally ensures the fire resistance due to its high thermal capacity. This research analyzed the fire resistance performance due to the variances of concrete strength filled inside of steel tube and the load ratios, which can influence on the fire resistance of CFT. As $280{\times}280{\times}6$ CFT columns with the concrete strengths of 24 MPa and 40 MPa and the axial load ratios of 0.9, 0.6, and 0.2 in accordance with KS F 2257-1 and 7 were heated with loading to examine the fire resistance performance, the fire resistance used to 24 MPa concrete showed 27, 113, and 180 minutes according to the axial load ratios, 0.9, 0.6, and 0.2 respectively. In case of 40 MPa concrete, the fire resistance were turned out to be 19 and 28 minutes for the axial load ratios, 0.9 and 0.6 respectively. The results of fire resistance with 40 MPa concrete showed the much lower fire resistance performance than those of 24 MPa concrete. In case of 40 MPa, the fire resistance performance was not increased significantly according to the axial load ratio than that of 24 MPa. The main reason why the higher concrete strength showed lower fire resistance than that of lower guessed the internal stress had the concrete strength weak.

• Proceedings of the Korean Society of Computer Information Conference
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• 2009.01a
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• pp.417-422
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• 2009

최근 웹 정보의 증가와 웹의 효율적인 구축에 대한 요구가 많아짐에 따라 대화형 웹 페이지를 위한 웹 도구로서 Ajax를 이용하는 웹 어플리케이션들이 급격히 증가하고 있다. Ajax의 가장 큰 장점은 Refresh 기능을 이용하여 페이지 이동없이 고속으로 화면을 전환 가능하며, 서버 처리를 기다리지 않고 비동기 요청이 가능하다. 이 논문에서는 이러한 장점의 활용을 위해 Ajax의 기능을 이용한 웹 사이트 구축한 결과 보인다. 기존 Ajax 성능 평가 방법의 분석을 통해 Ajax의 성능 평가의 한계점 및 향후 연구를 위한 추가 고려사항들을 도출한다. 기존 성능 평가 연구에 대한 분석 결과는 향후 Ajax 성능 평가를 위한 기초 자료로 이용 가능하며, 또한 구축된 웹 사이트는 기존 성능 평가 바탕으로 보다 다양한 성능 평가를 위한 실헝 데이터로 활용될 수 있다.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.119-126
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• 2002

본 논문에서는 chirp 변조를 이용한 통신 시스템의 LPI(low probability of intercept)와 AJ(anti-jamming)성능을 분석하였다. 인터셉터에 DAM(delay and multiplier)과 SC(squaring circuit)가 이용된 경우 CBPSK(Chirped BPSK)의 LPI 성능을 분석하였다. 스펙트럼 확산 방식의 CBPSK와 DS/BPSK 시스템에 대한 AJ 성능을 비교 분석 및 주파수 호핑 방식의 FH/CBFSK(Chirped BFSK)와 FH/BFSK, 그리고 FH/BCM(Binary Chirp Modulation) 시스템에 대한 AJ 성능을 분석하였다. LPI 결과로, CBPSK(Chirped BPSK)은 chirp 변수인 chirp 주기($T_3$가 커질수록 좋은 LPI 성능을 보인다. AJ 결과로, PBNJ(partial band noise jammer)환경에서 CBPSK 방식이 DS/BPSK 방식에 비하여 AJ 성능이 우수하고, 마찬가지로 FH/CBFSK 방식이 FH/BFSK 방식에 비하여 AJ 성능이 우수함을 시뮬레이션으로 확인하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.12 no.1
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• pp.79-87
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• 2008

Seismic performance evaluation of structure requires an estimation of the structural performance in terms of displacement demand imposed by earthquakes on the structure. Incremental Dynamic Analysis(IDA) is a analysis method that has recently emerged to estimate structural performance under earthquakes. This method can obtained the entire range of structural performance from the linear elastic stage to yielding and finally collapse by subjecting the structure to increasing levels of ground acceleration. Most structures are expected to deform beyond the limit of linearly elastic behavior when subjected to strong ground motion. The nonlinear response history analysis(NRHA) among various nonlinear analysis methods is the most accurate to compute seismic performance of structures, but it is time-consuming and necessitate more efforts. The nonlinear approximate methods, which is more practical and reliable tools for predicting seismic behavior of structures, are extensively studied. The uncoupled modal response history analysis(UMRHA) is a method which can find the nonlinear reponse of the structures for ESDF from the pushover curve using NRHA or response spectrum. The direct spectrum analysis(DSA) is approximate nonlinear method to evaluate nonlinear response of structures, without iterative computations, given by the structural linear vibration period and yield strength from the pushover analysis. In this study, the practicality and the reliability of seismic performance of approximate nonlinear methods for incremental dynamic analysis of mixed building structures are to be compared.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.793-795
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• 2005

영속적인 데이터 저장이 가능한 차세대 비휘발성 메모리를 휘발성 메모리와 혼용하여 버퍼캐처로 사용하면, 안정성과 성능향상의 효과를 얻을 수 있다. 본 연구에서는 기존의 연구에서 제시한 캐처관리 정책을 시뮬레이터를 이용하여 실험하고 실험 결과를 분석하여 비휘발성 메모리가 추가된 캐처의 새로운 특성을 밝혀냈다. 비휘발성 메모리가 캐쉬에 포함되면 읽기 쓰기의 요청의 종류, 미스(miss)되었을 경우 캐쉬될 블록의 더티(dirty)여부, 읽기 요청이 적중(hit)되었을 때, 적중된 블록의 메모리 종류에 따라 각각의 요청을 처리하기 위한 디스크 접근횟수가 달라지는 특성을 나타낸다. 이 특성 때문에 비휘발성 메모리가 추가된 버퍼캐처는 적중률(hit rate) 보다는 디스크 접근횟수를 측정하는 것이 정확한 성능측정을 가능하게 한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2019.06a
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• pp.32-34
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• 2019

최근 딥러닝 기반의 다양한 물체 검출 알고리즘이 제안되어 높은 성능을 보이고 있다. 본 논문은 이러한 딥러닝 기반 물체 검출의 성능을 향상시키기 위해 입력영상에서 추출된 특징 지도를 강화하는 비지역적 특징 융합과, 이를 이용한 물체 검출 기법을 제안한다. 제안 기법은 입력영상에서 CNN 을 통해 추출한 특징 지도를 비지역적 특징 강화 블록을 통해 강화한다. 해당 블록 내에서 입력된 특징 지도는 먼저 여러 리셉티브 필드를 갖는 특징 지도로 분기된다. 그리고 분기된 특징 지도들은 비지역적 특징 융합 모듈에 의해 융합되어 강화된다. 이러한 과정을 통해 강화된 특징 지도는 비지역적 문맥 정보가 강화된 특성을 가지며, 해당 특징 지도를 이용하여 최종적으로 물체 검출을 수행한다. Pascal VOC 공인 데이터세트를 통한 실험 결과, 제안 기법은 기존 비교 기법 대비 향상된 검출 성능을 보인다.