• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1863-1868
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• 2006

In this paper we propose the communication system model which improve the performance of OFDM based DSRC system by adopting selective pilot overlay channel estimation scheme. Assuming AWGN and fading channel environment, the performance of OFDM system according to IEEE802.11p physical layer being standardized for OFDM based DSRC is obtained, and the performance of proposed OFDM based DSRC system adopting selective pilot overlay channel estimation scheme is compared with the conventional system. from the simulation results, it is shown that proposed system is superior to conventional one due to reducing channel estimation error.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.4
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• pp.8-15
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• 2009

Relay-assisted multi-input multi-output (MIMO) technique has become a promising candidate for next generation broadband wireless communications for high speed access. In this paper, we propose channel selective relay-based MIMO transmission system. The performance of relay-based system can be improved by using the subcarriers selectively based on the channel condition between relay and mobile station. Simulation results show that the proposed relay-based system considerably outperforms the conventional relay-based system.

• 한국IT서비스학회:학술대회논문집
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• 2006.11a
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• pp.434-445
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• 2006

정보 기술의 발전으로 금융 채널의 다양화를 이루게 되었으며, 최근 인터넷 뱅킹에 이어 모바일 뱅킹이 도입되면서 금융 채널의 다양화와 급속화가 진행되고 있다. 이는 차별적 고객 채널의 도입과 운용의 필요성을 제시하며, 고객의 특성 및 거래액, 고객이 느끼는 각 채널별 특성을 고려하여 고객 만족 전략을 전개할 수 있음을 시사한다. 본 연구는 다양화된 금융 매체의 특성과 금융 업무 처리를 수행함에 있어 각 매체별 사용량에 영향을 미치는 요인의 차이는 어떤 것이며, 금융 채널의 사용에 영향을 미치는 매체의 특성들이 반영된 상황 발생시 상황에 얼마나 부합되는 금융 채널을 선택하는지에 대해서도 실증 분석하였다. 연구결과, 오프라인 매체라 할 수 있는 은행 창구와 ATM은 입지에 민감한 금융 매체임에 따라 편리성이 사용량에 영향을 미치는 요인으로 나타났으며, 온라인 매체라 할 수 있는 폰뱅킹, 인터넷 뱅킹, 모바일 뱅킹은 입지나 위치와는 상관없는 기술적 안전성이 보장되어야 하는 신뢰성이 사용량에 영향을 미치는 요인으로 나타났다. 본 연구에서는 금융 매체별 사용량에 영향을 미치는 특성을 파악함으로써 금융 기관의 차별적 고객 채널의 도입과 운용의 필요성을 제시하고 있다.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.7-17
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• 2015

To provide scalability, wireless sensor network has cluster-based architecture. Wireless sensor network can be implemented based on the IEEE 802.15.4 which is exploited in 2.4GHz ISM frequency band. Since this frequency band is used for various data communication, network status of wireless sensor networks frequently changes according to wireless environment. Thus, wireless channel selection to avoid reduction of transmission efficiency is required. This paper estimates network status using the information that a cluster-head collects in a cluster. Through objective function with throughput, RSSI level and reliability as input parameters, this paper proposes proper wireless channel selection. Simulation results show that the proposed method maintains transmission efficiency even though network status changes.

• Journal of Broadcast Engineering
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• v.7 no.2
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• pp.88-95
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• 2002

According to an evolution of digital broadcasting, it is possible that terrestrial and satellite broadcasting media provide multi-channel services. CATV and satellite media have been also extended to hundreds of channels. As the result of channel expanding, viewers came to select lots of channels. But it is difficult that they select the favorite channel among hundreds of channels. In this paper, we propose an efficient automatic method to recommend channels and programs on a viewer's preference in a multi-channel broadcasting receiver like a Set ToP Box(STB). The proposed algorithm selects channels based on the following method. It makes and saves user history data by using MPEG-7 MDS based on the program information a viewer had watched. It recommends programs similar to a viewer's preference based on user history data. It selects the channel in the recommended genre based on the viewer's channel preference. The experimental result shows that the proposed scheme is efficient to select the user preference channel.

• 한국경영정보학회:학술대회논문집
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• 2007.06a
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• pp.365-371
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• 2007

인터넷 쇼핑 시장의 확산과 함께 소비자들은 이전보다 더욱 다양한 형태의 인터넷 쇼핑몰을 접할 수 있게 되었다. 따라서, 소비자들은 다양한 쇼핑몰의 선택의 기로에 서게 된 반면, 인터넷 쇼핑몰 업체의 입장에서는 고객의 유지가 매우 중요하다. 특히, 오프라인 기반을 갖춘 Brick & Clicks 인터넷 쇼핑몰의 경우에는 오프라인 고객을 온라인상에서도 그대로 유지하길 바랄 것이다. 그러나, 실제로는 많은 고객들이 오프라인 쇼핑몰과 온라인 쇼핑몰을 동일하게 이용하는 Brick & Clicks 쇼핑몰을 선택보다는 인터넷 상의 순수한 Pure-play 쇼핑몰을 선택하기도 한다. 이에 본 연구에서는 소비자가 Brick & Clicks 인터넷 쇼핑몰이나 Pure-play 인터넷 쇼핑몰을 선택하는 행동에 대해 스키마 관점에서 살펴보고자 한다. 본 연구에서는 인터넷 쇼핑몰에 대한 스키마 형성에 신뢰, 구조적 확신, 관계혜택이 영향을 준다고 보고, 총 514여명의 인터넷 쇼핑몰 사용자를 대상으로 실증분석을 하고 결과를 도출하였다. 분석결과 Pure-play 인터넷 쇼핑몰이 고객에게 더 높은 평가를 받는 것으로 나타나 Brick & Clicks 인터넷 쇼핑몰의 특화가 필요한 것으로 판단된다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.46 no.7
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• pp.6-12
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• 2009

In this paper, we propose the opportunistic channel state information feedback scheme for eigen based scheduling in multiuser MIMO systems. According to 3GPP SMC channel model, the system capacity of MU-MIMO systems is severly degraded, since the antennas are highly correlated in urban macro cell. Although the eigen based scheduling scheme mitigates the adverse effect of the antenna correlation, it achieves only small amount of the multiuser diversity gain. Since the opportunistic channel state information scheme can achieve sufficient multiuser diversity gain, the system capacity of MU-MIMO systems can be improved. The system capacity improvement is verified by the computer simulation results.

• Journal of Digital Contents Society
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• v.15 no.2
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• pp.181-189
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• 2014

In this paper, using the demographic information of each member of a family, we figured out which member of a family has more influence on channel selection. We conducted an experiment which subdivide each breadwinners' income into 7 phases, and analysis the influence when they watch TV. The breadwinners' influence on TV channel selection is increased as breadwinners' income is getting higher. In the case of spouses, they have consistent influence on TV channel selection without reference to their breadwinners' income. We conducted another experiment which subdivide the youngest person's age in each family into 4 phases to watch the influence on TV channel selection. As the youngest person grows, they have more influence. With the experiments conducted in this paper, we could draw an interesting result, and this result is expected to provide good services such as content recommendation by considering the context of each family.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.7A
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• pp.768-775
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• 2008

In this paper, we consider downlink throughput performances of multiuser orthogonal frequency division multiplexing with reduced channel information feedback schemes. Specifically, two types of reduced feedback schemes, namely, 1-bit per sub-carrier and selective feedback scheme are considered and compared with each other in terms of average network throughput. Since the strict throughput comparison for given number of feedback bits per user is quite difficult, rather we compare their general behaviors in various system configurations with different system parameters, which can give us an insight into practical system design with those reduced feedback schemes.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.143-152
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• 2004

In this paper, we propose the new algorithms of watermarking that utilize the characteristics of color images for solving the trade-off problem between the image quality and the robustness. Since the human visual characteristics of each RGB channel are different, we can gain more robust watermarking on the condition of the same image degradation.