Time filter

Source Type

Yanggu, South Korea

Kim E.C.,Samsung | Kim J.Y.,Wolgye Dong
17th ITS World Congress | Year: 2010

In this paper, we propose and simulate an intelligent transportation system (ITS) employing multi-hop cooperative communication scheme for enhancing system performance. Streetlights are adopted as the relays for multi-hop communications in the ITS. It is assumed that visible light is used for lighting up the street and streetlights utilized in this paper can perform visible light communication (VLC). It is also assumed that a communication channel is an optical wireless channel. The system performance is evaluated in terms of bit error probability. And the system performance of the proposed system is compared with that of a single-hop communication system. From simulation results, it is shown that the performance of the single-hop system decreases significantly as the distance between the transmitter and the receiver increases. However, the proposed system shows almost uniform performance regardless of distance between a transmitter and a receiver. In addition, it is confirmed that, in spite of the low power consumption, the proposed ITS employing multi-hop relays shows better performance than the single-hop system does irrespective of distance between the transmitter and the receiver. The results in this paper are of interest in cooperative communication-based ITS applications. Source

Kim S.J.,Wolgye Dong | Kim E.C.,Wolgye Dong | Kim J.Y.,Wolgye Dong
17th ITS World Congress | Year: 2010

In this paper, we propose and simulate reliability of Hi-pass system with cooperative sensing for ITS (Intelligent Transportation System). Hi-Pass System is based on DSRC (Dedicated Short Range Communication) system. DSRC is a wireless network using ITS, including GPS satellites in conjunction with the national transportation system. DSRC communication scheme are methods of IR (Infrared) and RF (Radio Frequency). Hi-pass of this paper is adopted as RF communication. The system performance is evaluated in terms of bit error probability. In the simulation, the vehicle speeds are set at 30 km/h and 60 km/h, respectively. The carrier frequency is set at 5.8 GHz. Wireless channel is modeled as the Rician fading channel. Rician k-factor is 6.5 dB. In the transmitter, the ASK (amplitude shift keying) modulation scheme is applied. The system performance of the proposed scheme is compared with that of a 1 antenna system. From simulation results, proposed scheme is apply to 2 antennas and it is confirmed that, reliability of Hi-pass system is increased. Especially, in case of low speed, the proposed Hi-pass sensing system shows better performance than existing methods. In addition, we implemented a value of BER depending on Rician k-factor. Source

Nam J.-H.,Wolgye Dong | Jung K.-S.,Wolgye Dong | Jo H.-H.,Wolgye Dong | Sim D.,Wolgye Dong | Choi B.-D.,Wolgye Dong
Optical Engineering | Year: 2012

We propose context-based adaptive in-loop filters not only to reduce complexity but also to achieve coding efficiency by combining deblocking and in-loop filters. The proposed adaptive filters are designed based on contexts such as slice types, boundary strength values, pixel positions, and boundary directions in order to improve coding gain. The proposed method is also embedded with a deblocking filter to reduce complexity and to maintain subjective quality. Experimental results show coding gains of approximately 6.3% and 0.5% compared with the deblocking filter of H.264/AVC and the conventional block-based adaptive loop filter, respectively. Then the proposed method reduces complexity by about 20.8%. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). Source

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