• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.89-90
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• 2019

본 논문에서는 D2D 단말이 셀룰라 시스템의 상향링크 자원을 재사용하는 환경에서 D2D 단말들의 효용함수 극대화 방안을 제안한다. 기존 셀룰라 단말의 간섭영향을 고려하여 기지국 수신단 총 간섭량을 제한하고, D2D 송신단 전송전력량을 제한한다. D2D 단말들의 효용 극대화를 위해서는 모든 링크간의 채널 정보를 요구하므로, 부분적인 링크 채널 정보만을 필요로 하는 분산적 알고리즘을 제안하도록 한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.3
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• pp.129-135
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• 2011

In this paper, we propose the algorithm using optical flow and machine learning-based segmentation for the 3D conversion of 2D video. For the segmentation allowing the successful 3D conversion, we design a new energy function, where color/texture features are included through machine learning method and the optical flow is also introduced in order to focus on the regions with the motion. The depth map are then calculated according to the optical flow of segmented regions, and left/right images for the 3D conversion are produced. Experiment on various video shows that the proposed method yields the reliable segmentation result and depth map for the 3D conversion of 2D video.

• Journal of the Korea Society of Computer and Information
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• v.23 no.8
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• pp.51-57
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• 2018

In this paper, we investigate the impact of channel estimation error on the D2D power control algorithm. In the previous work, D2D power control algorithm has been proposed under the assumption that the channel between the transmitter and the corresponding receiver is perfectly estimated. In reality, the channel estimation error is more often the case. The first question is that the power control algorithm designed for perfect channel estimation is still valid under the channel estimation error environment ? The second question is, if it is not valid, what could be the possible remedy for the channel estimation error ? In this paper, to answer the first question, we investigate the impact of the channel estimation error on the power control algorithm. We first review the D2D power control algorithm designed for perfect channel estimation. Then, we model the channel estimation error. Finally, we summarize the main results observed from the analysis of the simulation.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.127-128
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• 2018

본 논문에서는 채널추정에러가 존재하는 셀룰라시스템 환경에서 D2D 통신을 위한 전력제어 알고리즘 운용방안을 제안한다. 전력제어의 목적은 요구하는 SIR 값을 유지하는 것이다. 하지만, 채널 추정에러 환경에서의 SIR 성능은 확률적 분포를 가지게 된다. 이러한 확률적 SIR 성능 분포를 고려하여, 채널추정에러를 보상하는 가변적인 SIR 적용과 재전송 기법을 복합하여 D2D 통신을 위한 전력제어 기법을 제안하도록 한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.129-130
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• 2018

본 논문에서는 셀룰라시스템 환경에서 특히, 채널추정에러가 존재하는 환경에서 D2D 통신을 위한 전력제어 알고리즘 성능을 분석한다. 채널추정에러의 성능분석을 위해 가우시안 채널 추정에러를 모델링하였으며, 이는 SIR 성능이 확률적 분포를 가지도록 한다. 실제 전송환경에서는 송신단과 수신단 사이의 채널환경 변화로 인해 채널 추정 에러는 불가피하다. 이러한 채널추정 에러가 D2D 단말 전력제어 알고리즘에 어떻게 영향을 주는지 실험을 통하여 분석하도록 한다.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.925-928
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• 1998

In this paper, we implemented a sign language communication system between korean and japanese using 3D model. Unitl now, we have developed the system through 2D image. The system, however, has some drawbacks base don the limitations of 2D model. Especially it is not comprehensive in the sign language gesture including forward or backward movements becasue it can only display a front view. Therefore, we employed a 3D model for the representation of sign language. The proposed communication system si implemented with windows 95 visual C++ 5.0 imported open inventor library on pentium 233 system. Experimented results show that the 3D system can solve the problems in 2D representation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.10
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• pp.941-944
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• 2016

This paper proposes 24 GHz power amplifier for automotive collision avoidance and surveillance short range radar using Samsung 65-nm CMOS process. The proposed circuit has a 2-stage differential power amplifier which includes common source structure and transformer for single to differential conversion, impedance matching, and power combining. The measurement results show 15.5 dB maximum voltage gain and 3.6 GHz 3 dB bandwidth. The measured maximum output power is 13.1 dBm, input $P1_{dB}$ is -4.72 dBm, output $P1_{dB}$ is 9.78 dBm, and maximum power efficiency is 17.7 %. The power amplifier consumes 74 mW DC power from 1.2 V supply voltage.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.4
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• pp.229-239
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• 2013

Recently, device-to-device (D2D) communications have been highlighted to improve the spectral efficiency and offer various user experiences in cellular networks. In this paper, we survey standards and literatures related to the D2D technology and address various advantages of D2D technology, and the problems to be resolved before practically implemented. Especially, by considering an important interference issue between cellular and D2D links, five resource allocation and interference management scenarios are provided and their performances are evaluated through the system level simulations. The simulation results show that the use of D2D significantly improve the cell capacity and the D2D user rate due to the effects of frequency reuse and data off-loading. Notably, it is also shown that an optimal D2D communication range exists to maximize the system performance.

• Journal of Satellite, Information and Communications
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• v.3 no.2
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• pp.54-59
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• 2008

Traditionally R&D evaluation has been performed by experts who can understand the contents of the study area very well. Recently extensive application of quantitative evaluation methods have been attempted for introducing the administrative management system that poses greater importance on records and results. More objective reviews on the R&D outcomes are called for gaining public supports. In this paper a bibliometrical analysis is to be performed to evaluate satellite communication and broadcasting public R&D outcomes for last 7 years. Data envelopment analysis method is selected for evaluating the efficiencies of multiple outputs (papers, patents, royalties, technology transfers) where multiple inputs (number of researchers and R&D expenses) are given. R&D outcomes from 22 research institutes are being compared and satellite communication and broadcasting R&D efforts turn out to be highly efficient.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.5
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• pp.33-47
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• 2015

Cellular Network assisted device-to-device (D2D) communication has been growing to reduce the overload of eNodeB and mitigate the frequency shortage. However, by sharing the uplink frequency resource with the cellular network, the interference between cellular and D2D is increased. In this paper, we propose an advanced receiver for full suppression cancellation (FSC) to reduce the interference between cellular and D2D. The proposed receiver can suppress and cancel the interference by integrating the interference rejection combining (IRC) technique with successive interference cancellation (SIC). We perform a system level simulation based on the 20-MHz bandwidth of the 3GPP LTE-A system. Simulation results show that the proposed receiver can improve SINR, throughput and spectral efficiency compared to conventional receivers.