• 한국통신학회논문지
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• 제41권4호
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• pp.404-414
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• 2016

So called quaternary quasi-orthogonal sequence spatial modulation (Q-QOS-SM) has been presented with an advantage of improved throughputs compared to the conventional SM and generalized spatial modulation (GSM) by virtue of a larger set size of QOSs and its minimized correlation value between these QOSs. However the Q-QOS-SM has been originally invented for limited transmit antennas of only powers of two. In this paper, by extending the Q-QOS-SM to any number of transmit antennas, we propose a generalized Q-QOS-SM, referred as G-QO-SM. Unlike the conventional Q-QOS-SM using the Q-QOSs of length of any power of two, the proposed G-QO-SM is constructed based on the Q-QOSs of only the lengths of 2 and 4. The proposed scheme guarantees the transmission of the total $N_t$ spatial bits with $N_t$ transmit antennas, and thus achieves greatly higher throughputs than the other existing schemes including the SM, GSM, Q-QOS-SM, Quadrature-SM, and Enhanced-SM. The performance improvements of the proposed G-QO-SM is justified by comparing the analytically derived BER upper bounds and also the exact Monte Carlo simulation results.

• 한국측량학회지
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• 제31권5호
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• pp.355-363
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• 2013

웹 기반으로 공간분석 모델을 공유하면 개발된 공간분석 프로세스 재활용이 가능하며 사용자가 공간분석 모델에 쉽게 접근할 수 있으므로 공간정보의 활발한 분석과 정보의 교류를 기대할 수 있다. 그러나 웹 기반의 공간분석 모델 배포는 모델 설계의 어려움과 공간 데이터 교환의 어려움 때문에 한계가 많다. 본 연구에서는 상수도 보급 대상 가구 선정이라는 사례로 OGC 표준 기반의 공간분석 WPS 모델을 정의하였다. 정의된 모델을 처리 순서, 공간 데이터 교환을 가능하게 하도록 BPEL 표준을 적용하였다. 외부에서 제공되는 WPS와 WFS에 접근하기 위한 WSDL를 정의하였으며, 공간분석 처리 순서를 설계하기 위하여 BPEL을 정의하였으며, XML 데이터 교환을 위한 XSLT를 정의하였다. 또한, BPEL을 실행하기 위해 RESTful 바인딩을 제공하는 Apache ODE 엔진 구축을 통해 공간분석 WPS 모델을 설계 및 배포하였다. 본 논문에서 제시한 방법으로 BPEL 적용을 통한 WPS Orchestration이 쉽게 정의되어, 공간분석 모델을 웹으로 쉽게 배포할 수 있으므로 효과적인 의사 결정을 기대할 수 있다.

• 한국멀티미디어학회논문지
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• 제4권6호
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• pp.554-561
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• 2001

워터마킹 방법 중에서 주파수 특성과 공간영역의 특성을 함께 가지고 있는 웨이브릿 변환 알고리듬이 많이 사용되고 있다. 본 논문에서는 다양한 공격에 대해 강인한 워터마킹을 갖는 시퀀스를 찾기 위해 임의난수, 가우시안 시퀀스, 카오스 시퀀, 소벨 시퀀스를 이용하여 유사도를 측정하였다. 실험 결과는 카오스 시퀀스가 다양한 공격에도 강인한 특성을 갖는 시퀀스라는 것을 검증하였다.

• 한국컴퓨터정보학회논문지
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• 제6권4호
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• pp.21-29
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• 2001

본 논문에서는 웨이브릿 변환 알고리듬을 이용하여 영상을 다해상도 변환하고, 중간주파대역의 중요한 계수에 각종 워터마크 시퀀스를 삽입 후 이의 강인성을 유사도 비교를 통하여 측정한다. 웨이브릿 변환은 주파수 영역 특성과 공간 영역의 특성을 함께 갖고 있는 장점을 가지고 있으며, 워터마크로는 임의 난수, 가우시안 시퀀스, 카오스 시퀀스 그리고 소벨 시퀀스를 이용한다. 다양한 공격에 대하여 실험한 결과 카오스 시퀀스가 다른 시퀀스들에 비해 높은 유사도를 보임으로써 향후 워터마크 시퀀스로 사용하기에 적합함을 보인다.

• 한국주거학회논문집
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• 제12권3호
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• pp.109-116
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• 2001

Street is an important factor that street quality determines urban quality as the space of the high public nature in city. The research method considering sequence landscape is important because it is considered that the impression of such a street is formed by the wholeness of consecutive landscape and experience in moving street. Therefore, this study are pursued to structure the analysis of psychological evaluation and environmental attribute base on the physical characteristics of sequence landscape to supply the basic materials for seeking the national direction as qualitative improvement of urban street space and the attractive urban street space. Then the results are as follows. It is shown that the psychological evaluation structure of sequence landscape is evaluated by ornamental nature, intimacy, orderliness, openness and movability and that of environmental attributes is evaluated by four factors such as activity, intimacy, spatial attribute and openness.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2006년도 가을 학술발표논문집 Vol.33 No.2 (C)
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• pp.83-87
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• 2006

Similarity search in moving object trajectories is an active area of research. In this paper, we introduce a new concept of measure that computes spatial distance (similarity) between two trajectories of moving objects on road networks. In addition, we propose an algorithm that generates a sequence of matching edge pairs for two trajectories that ate to be compared and computes spatial distance between them which is non Euclidian in nature. With an example, we explain how our algorithm works to show spatial similarity between trajectories of moving objects in spatial network.

• 한국실내디자인학회논문집
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• 제23권2호
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• pp.108-116
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• 2014

This study is based on the arguments of Sofia Sarah and concept of 'Sequence Narrative' of Nigel Coates, the founder of Nato. Specifically, this study was conducted under the premise that narrative exhibition space will affect the engagement of viewers. As a result of this study, a method of analyzing a science museum's exhibition space was presented using the narrative structure and the following attributes of visuals: sequence of viewing; spatial tension; spatial pace. The findings are as follows. In terms of 'spatial tension', the exhibiton space with the following progression was more likely to provide viewers with in-depth experience: 'raise of tension' - 'change of pace' - detente.' Although the limited sample doesn't lead to verification of the analysis method and conclusion of its significance, the following was clearly revealed: Exhibiton space that utilizes the structure and attributes of a narrative that provides progression and dramatic tension, as if the viewers were watching a film, is more likely to offer in-depth experience than other spaces. In terms of 'phase transition', the following was revealed: Pace variation around the space with the strongest spatial tension could affect the concentration and engagement of viewers. It suggests the following fact: Spatial rhythm and speed variation in the area with the strongest visual emphasis encourage viewers to feel the spatial changes, maintain their concentration, and continue their viewing.

• 한국통신학회논문지
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• 제40권4호
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• pp.637-645
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• 2015

Recently, a spatial modulation (SM) scheme achieving high throughput based on quaternary quasi-orthogonal sequences (Q-QOSs), referred to as Q-QOS-SM, is presented for $N_t=2^n(n=1,2,{\cdots})$ transmit antennas. In this paper, based on the design approach of the conventional Q-QOS-SM, new improved QO-SM (I-QO-SM) schemes are proposed for 8 transmit antennas. The new schemes employ Q-QOSs of length 4 or 2 unlike of 8 in the original one, which guarantees more information bits to be allocated for antenna index parts compared to the conventional Q-QOS-SM. By computer simulation results, the proposed scheme are shown to enjoy much higher throughputs compared to the conventional other SM schemes for all simulation environments. Finally, we also examine and compare analytically the performances of the new and conventional SM schemes by calculating upper-bounds on BER performance.

• 천문학회보
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• 제41권1호
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• pp.46.1-46.1
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• 2016

The formation process of a current sheet is important for solar flare from a viewpoint of a space weather prediction. We therefore derive the temporal development of the spatial and statistical distribution of electric current density distributed in a flare-producing active region to describe the formation of a current sheet. We derive time sequence distribution of electric current density by applying a nonlinear force-free approximation reconstruction to Active Region 12158 that produces an X1.6-class flare. The time sequence maps of photospheric vector magnetic field used for reconstruction are captured by a Helioseismic and Magnetic Imager (HMI) onboard Solar Dynamic Observatory (SDO) on 10th September, 2014. The spatial distribution of electric current density in NLFFF model well reproduce observed sigmoidal structure at the preflare phase, although a layer of high current density shrinks at the postflare phase. A double power-law profile of electric current density is found in statistical analysis. This may be expected to use an indicator of the occurrence of a solar flare.

• 한국통신학회논문지
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• 제24권12B호
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• pp.2401-2406
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• 1999

압축된 비디오 데이터에서 내용기반 컷 검출을 위해 다양한 특징 벡터 추출 방법이 연구되고 있다. 특징 벡터로써 화소값의 히스토그램을 이용한 방법의 경우 화소의 공간적 특성을 고려하지 않아 정확히 컷 검출을 기대하기 어렵다. 그래서 CCV(Color Coherent Vector)나 Color Correlogram등의 계산량이 복잡한 알고리즘이 많이 사용된다. 그러나 이러한 기법들은 정확한 컷 검출을 가능하게 하나 계산량이 너무 복잡하기 때문에 검출 시간이 많이 소요되는 단점이 있다. 본 논문에서는 MPEG 비디오 시퀀스에서 휘도성분의 DC값들의 공간적 상관도를 이용한 컷 검출 기법을 제안한다. 이 기법은 비교적 간단하기 때문에 처리 시간이 빠르며 또한 개선된 특징차 비교방법을 이용하여 검출율을 더 높일 수 있다.