• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.59.2-59.2
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• 2014

Radiative transfer models in a spherical, turbulent interstellar medium (ISM), in which the photon source is situated at the center, are calculated to investigate the correlation between the scattered light and the dust column density. The medium is modeled using fractional Brownian motion structures that are appropriate for turbulent ISM. The correlation plot between the scattered light and optical depth shows substantial scatter and deviation from simple proportionality. It was also found that the overall density contrast is smoothed out in scattered light. In other words, there is an enhancement of the dust-scattered flux in low-density regions, while the scattered flux is suppressed in high-density regions. The correlation becomes less significant as the scattering becomes closer to being isotropic and the medium becomes more turbulent. Therefore, the scattered light observed in near-infrared wavelengths would show much weaker correlation than the observations in optical and ultraviolet wavelengths. We also find that the correlation plot between scattered lights at two different wavelengths shows a tighter correlation than that of the scattered light versus the optical depth.

• ETRI Journal
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• v.37 no.3
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• pp.439-449
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• 2015

Human body communication (HBC) is being recognized as a new communication technology for mobile and wearable devices in a body area network (BAN). This paper presents co-channel interference experienced by HBC supporting the physical layer in the IEEE 802.15.6 BAN standard. To analyze the co-channel interference, a co-channel interference model is introduced, and space-domain and time-domain parameters representing an interference environment are generated using the co-channel interference model. A new signal-to-interference ratio (SIR) parameter depending on the peak amplitudes of the data signals causing co-channel interference is defined; co-channel interference can be easily analyzed and modelled using the newly defined SIR. The BER degradation model derived using the co-channel interference model and SIR in this paper can be effectively used to estimate the performance.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.45-46
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• 2015

사람 검출 시스템은 카메라의 위치 및 각도 등에 큰 영향을 받는다. 이로 인해 획득한 2D 영상에서 사람은 위치에 따라 각기 다른 크기를 갖는 형태로 나타난다. 이러한 요인들은 사람 검출 시스템의 실시간 구현을 어렵게 만드는 요인이 된다. 본 논문에서는 실내 공간의 구조를 깊이맵으로 구성하여, 이로부터 3D 공간을 구성한다. 3D 공간에서는 어느 위치에서든지 사람의 크기가 일관되므로 이를 2D 영상으로 투영하게 되면 2D 영상의 좌표에 따른 정확한 사람의 크기를 추정할 수 있다. 실험 결과로부터 제안 방법의 타당성을 입증하였다.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.397-398
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• 2007

In this paper, we have verified the applicability of the line-clustering segmentation method to steel-tube X-ray images. Image data is partitioned into three regions on the base of vertical line edge detection. Parameters for necessary condition, such as neighborlity, similarity and directional neighbor correlation coefficients, proposed in that method is calculated and applied to such selected regions separately Segmental features at each region is extracted statistically and functional classification is clustered by the point or space process. The analyzed data and experimental results show that the line-clustering segmentation method has a high applicability to X-ray image.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.399-400
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• 2007

This paper proposes an regional analytic approach in image data space for radiographic image. Image is segmented into four regions, such as background, thickness, weld area and tube area, due to directional properties. Each region has its own gray level distribution, contrast range and noise property, originated from X-ray project mechanism and electric control system itself. Projection incorrectness and noise influence included on imaging quality is analyzed functionally and statistically. The experimental results shows not only segmental effects, but also visual edge evaluation.

• Geotechnical Engineering
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• v.13 no.1
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• pp.101-110
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• 1997

This paper presents a two dimensional p-version static infinite element for analyzing $1/r^n$ displacement decay type problems in unbounded media. The proposed element is developed by using shape functions based on approximate expressions of an analytical solution. Numerical results are presented for an opening in a homogeneous elastic infinite medium and a rigid footing rested on a homogeneous elastic half-space. The numerical results show the effectiveness of the proposed infinite element.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.11a
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• pp.108-111
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• 2013

최근 들어 무선 통신 트래픽이 급증하고 있다. 때문에 주파수, 시간 등과 같은 무선 통신 자원의 효율적 활용이 매우 중요해 지고 있다. 이러한 관점에서 스펙트럼 효율이 낮은 단방향 중계 시스템에 비해 이론적으로 약 2배에 가까운 스펙트럼 효율을 갖는 양방향 중계 기술에 대한 연구가 최근 들어 활발히 이루어지고 있다. 하지만 양방향 중계 시스템이 갖는 높은 스펙트럼 효율을 극대화하기 위해서는 단방향 릴레이 시스템에 비하여 증가하는 오버헤드의 증가량을 최소화하면서 요구 성능을 만족하는 것이 매우 중요하다. 이러한 문제를 해결하기 위한 하나의 대안으로 본 논문에서는 증폭 후 재전송(amplify-and-forward) 양방향 중계시스템에서 결합적 간섭제거 및 채널 등화를 위한 적응형 수신기를 제안한다. 제안하는 수신기는 적은 오버헤드만을 갖기 때문에 양방향 중계기술이 갖는 높은 스펙트럼 효율을 그대로 유지할 수 있으며, 복잡도가 높은 역행렬 연산 없이 채널 추정 기반 최소평균자승에러 (minimum mean-square error) 수신기가 갖는 성능을 제공한다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.07a
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• pp.504-506
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• 2015

RFID란, 무선 주파수를 이용해 원거리에서 태그의 정보를 판독하거나 인식할 수 있는 객체 인식 기술 중 하나이다. 최근 바코드를 대체하여 RFID 기술을 이용하는 산업이 물류, 유통, 환경, 보안 등 다양한 분야에 걸쳐 전 세계적으로 성장세를 보이고 있는 추세이다. 특히 RFID 기술 중 위치 탐지 및 측정 기술을 이용한 사례가 많다. 본 연구에서도 이러한 기술을 이용하여 공항이나 쇼핑몰 등과 같은 넓고 개방된 공간에서 객체들을 추적하는 시스템을 구현하고자한다. 모든 객체들이 RFID를 가지고 있는 환경에서 Cluster와 센서 네트워크를 이용해 RFID를 감지하면 RFID의 데이터를 서버에 전송하고 서버는 이 데이터들을 분석하여 객체의 위치 및 동선을 추적한다. 객체 추적을 함으로써 정확하고 신뢰성이 있는 데이터를 얻는 것을 본 연구의 목적으로 한다.

• Korean Institute of Interior Design Journal
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• no.29
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• pp.3-10
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• 2001

In recent years when the importance of public communication is more emphasized, it has to be noticed that we are now living in the public-initiated age of rhetoric resulted from rapid development of broadcast media. Therefore, the purpose of this treatise is to examine the structural characteristics in the fusion design in order to anaylize the rhetorical expressions as symbols of communication. One of those is intertextuality that expresses metaphorically by bleding and borrowing codes and another is hypertextual space where various texts twines around each other making brand-new and diverse organizations, as the combined allegory with a number of hidden expression. The fusion design may be understood as the Intention to attract gaze to visual messages and as the rhetorical expressions based on compounding aesthetic codes by producing new cultural meanings. If fusion, a phenomenon which represents the 21st century, not a passing fad of cultural mixture, is ready to take the initiative, the design has to be groped for that creates a synergy effect.

• Journal of Sensor Science and Technology
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• v.24 no.5
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• pp.342-347
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• 2015

We introduce an indoor broadcasting system using light-emitting diode (LED) lamps coupled with a 220 V power line. Two couplers connected to the power line constitute a power line communication (PLC) link. The transmission path from an LED lamp to a photodetector forms a visible light communication (VLC) link in free space. When the LED lamp is coupled to the power line, a composite PLC-VLC link is formed, making it possible to transmit a VLC signal beyond line-of-sight. In experiments, a 4 kHz analog signal modulated with a 100 kHz carrier was sent to the power line by a PLC coupler, and LED lamps coupled to the power line detected the signal and radiated it to multiple VLC receivers in the room. This configuration is useful in expanding an indoor VLC sensor network to adjacent rooms or constructing a voice broadcasting system in a building or apartments with existing power lines.