• The Journal of the Acoustical Society of Korea
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• v.17 no.4
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• pp.67-71
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• 1998

초음파 선형트랜스듀서에서 제한회절음장은 영상깊이에서 다른 방향으로 진행하는 평면파들의 선형적인 중첩으로부터 구한다. 제한회절음장을 구현하기 위한 송신음장은 영상 깊이를 지나가는 평면파들의 공간적인 확장으로부터 구해지는데 실제의 하드웨어로 구현하 기 어렵다. 본 논문은 진행방향이 다른 pulsed mode 평면파를 각각 송신한 후, 얻어진 데이 터로부터 합성집속 방법에 의하여 제한회절빔을 구현하였다. 제안한 방법은 모든 송신소자 에서 발사되는 음장의 크기가 동일하므로 송신전력이 증가하여 신호대잡음비와 명암비를 증 가시키며 간단한 하드웨어로 구현이 가능하다. 시뮬레이션 결과는 송신은 한점집속, 수신은 동적집속을 사용하는 기존의 방법과 비교하여 주엽(mainlobe)의 폭과 부엽(sidelobe)의 크기 관점에서 우수함을 증명하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.05a
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• pp.560-563
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• 2021

본 논문에서는 사각형 실내 공간에서 점군 데이터를 기반으로 빠르고 정확하게 바닥, 천장, 벽면에 대한 평면 정보를 획득할 수 있는 시스템을 제안한다. 기존의 방법은 관측되지 않은 공간에 대한 평면을 예측할 수 없으며, 노이즈에 취약하고, 모든 점에 대한 기저 정보를 알아야하기 때문에 많은 연산량을 요구한다. 제안 방법은 기존의 평면 검출 방식에서 벗어나 Bounding Box 형상을 예측하는 기술을 활용한다. 또한, 제안 시스템은 구면 파노라마 비디오를 기반으로 적은 수의 프레임으로도 빠르게 실시간 점군 데이터를 확장해나간다. 제안 방법은 실험을 통해 기존의 방법보다 월등히 빠르고, 노이즈 등 환경 제약 요소에 강건함을 보인다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.3
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• pp.245-251
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• 2001

Nowadays, the first design elements of horizontal alignment are very important things to extension or improvement of highway. When the design elements ale lost or damaged, it is necessary to recalculation. In this paper, an investigation is made on the method of representation of horizontal alignment as a result of design element using generalization method. The results show that northing calculated about 0.2∼5 meters and easting calculated about 1∼40 meters between calculated and design data. Because the maximum value is a very small compared to total horizontal alignment length. calculated data have been fined to presentation of observed highway.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.5
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• pp.402-408
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• 2016

In this paper, a new approach to the terminal sliding mode control using adaptive fuzzy sliding surfaces is proposed. The idea behind this approach is to utilize an adaptive sliding surface, in which the slope of the surface is updated on line using a SISO fuzzy logic inference system. We expanded the concepts of terminal sliding mode controller and proposed the terminal sliding mode control input with continuous reaching laws. The computer simulation results have shown the improved performance of the proposed control approach in terms of a decrease in the reaching and settling times and chattering free as compared to the conventional terminal sliding mode control with a fixed sliding surface. The proposed controller has also an advantage that has less computational burden to the conventional terminal sliding mode control using one-directional fuzzy rules.

• Tunnel and Underground Space
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• v.12 no.3
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• pp.158-170
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• 2002

Since the development of Discontinuous Deformation Analysis (DDA) by Shi (1984), there has been much improvement in the theory and programs. These, however, are all based on the assumption of a two-dimensional plane strain or plane stress state; and because a rock block system is a three-dimensional problem, a two-dimensional analysis has limited application. So a three-dimensional analysis is required in the design of rock slopes and underground spaces where three-dimensional discontinuities dominate stability. In this study three-dimensional DDA program is developed using the Shi's two-dimensional theory and program, and the two cases of three-dimensional block are analysed. The program is applied to one sliding-face blocks and wedge sliding and it gives the good results comparing to the exact solution. Multi-block cases will be analysed for many other application soon.

• Journal of the Korean housing association
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• v.21 no.3
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• pp.33-40
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• 2010

Apartments have been the most prevalent type of housing in Korea for the past few decades. During those times, apartments have emerged as one of the most attractive real estate properties in Korea, with the still growing population living in them. Now that over twenty years have passed since the 1970s and 1980s when apartment construction started booming, building stocks are increasing that need refurbishment. In this concern, apartment extension has raised public interest for the past few years, as the remodeling of them has mainly been considered in terms of increasing asset value in Korea. It comes through in our study that these extension types are examined by such items as building core types, number of rooms and front and rear bays in unit, and other design features related to extension techniques. The objective of this study is to suggest a way to produce the best quality possible of unit plan through extension.

• Journal of KIISE:Software and Applications
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• v.36 no.8
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• pp.642-652
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• 2009

In order to improve the performance of the existing relation extraction approaches, we propose a method for combining two pivotal concepts which play an important role in classifying semantic relationships between entities in text. Having built a composite kernel-based relation extraction system, which incorporates both entity features and syntactic structured information of relation instances, we define nine classes of lexical features and synthetically apply them to the system. Evaluation on the ACE RDC corpus shows that our approach boosts the effectiveness of the existing composite kernels in relation extraction. It also confirms that by integrating the three important features (entity features, syntactic structures and contextual lexical features), we can improve the performance of a relation extraction process.

• Journal of the Korean Institute of Rural Architecture
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• v.10 no.2
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• pp.61-70
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• 2008

The purpose of this study is to give some suggestions for the legal supplement of the regulation on the balcony expansion for the optimal use of apartment balcony. For the purpose, this study focused on the characteristics of spaces expanded to the balcony, in the plans supplied after the legalization of balcony expansion, comparing them by their location; the metropolitan area of Seoul Gyeonggi and the districts of the other areas. The 168 plans of apartments in the supplied by top 10 constructors in the metropolitan areas of Seoul and Gyeonggi, together with the 92 plans in the other smaller districts in 2006 to 2007 were analyzed with the tools of frequency and chi-square analysis. The result is as follows. (1) The region showed no difference in the plans of balcony; whereas the size, the position and access of the shelter explained some differences of balcony plan. (2) In wider plans, balconies were placed in all sides of plan-front, rear and side, and were remodeled to expand facing rooms. (3) The balcony expansion tended to increase the number of bays. (4) In almost cases, the living rooms were expanded to balcony. In smaller plans, the balconies were remodeled to supply supplementary kitchen space, splitting it from laundry. (5) The shelters were placed at the rear or side of plans, but the shelter facing room could be dangerous in case of fire. The balcony expansion, despite of legalization spirit to adopt diverse use of additional spaces for residents' needs, was only a tool for the space expansion. The amendment of the regulation is needed to accommodate these findings that the balconies should be identified by their function, that the front corridor-type balcony should be limited in length and magnitude, and that the shelter should be positioned with easy access.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.3C
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• pp.323-330
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• 2007

Performance indicators such as output SNR, SIR, SINR for rectangular smart antennas in CDMA basestations have been derived. Simulations have been carried out to find the rectangular smart antenna performance while varying the input SNR, number of antenna elements, and the interferers' spatial distributions. Simplified Conjugate Gradient Method was chosen as the underlying beam forming algorithm. It has been shown that the performance of a rectangular smart antenna is similar to that of the linear one having the same number of elements when the interferers are randomly distributed over the whole azimuth angle range.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.65-66
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• 2018

국내 항만의 건설 및 확장 보수를 위한 설계 단계에서의 평면배치 검토시 항내측으로 내습하는 파랑변형특성에 대한 정밀한 평가는 필수적이다. 이에 따라 많은 수학적 모델들이 연안역과 항만에서의 파랑전파와 변형에 대해 개발되어 왔다. 특히 항내정온도의 해석은 항만 사용성 측면에서 매우 중요하며 실제 해상의 파랑상태와 유사한 불규칙파로의 해석이 요구되어 지고 있다. 항내정온도 해석에 있어서 항내파랑장 형성에 크게 영향을 미치는 구조물의 반사율을 효과적으로 적용하는 것은 매우 중요하다. 하지만, 구조물의 반사율은 이론계산이 어렵고, 일반적으로는 모형실험 혹은 현지관측에 의해 추정된다. 따라서, 일반적인 경우 비용 및 시간상의 제약으로 인해 평면 파랑모형으로 정온도 해석시 반사율의 적용은 구조형식별로 연구자들에 의해 개략 제시된 반사율을 적용하고 있다. 특히, 다방향 불규칙파의 적용시에 경계조건으로는 다방향 불규칙파를 효과적으로 제어할 수 있는 부분반사 경계면과 계산영역 밖으로 나가는 파랑에 대해서 인공적인 흡수층 또는 감쇠층(artificial damping layer)을 설정하여 반사를 제어하는 기법을 많이 적용하고 있다. 이때 항만구조물의 부분반사는 파랑제원에 따른 damping layer의 parameter의 조정에 의해 구조물의 구조형식별 반사율을 적절히 재현할 필요성이 있다. 본 연구에서는 불규칙파를 대상으로 damping layer의 parameter(무차원 감쇠계수, 감쇠층의 두께)등의 변화에 따른 반사율의 변화특성을 고찰하고, 향후 부분반사 경계면으로 damping layer가 적용되는 평면 파랑모형의 정온도 해석시 부분반사의 적용에 대한 기초자료를 제공하고자 한다.