• 한국정보시스템학회지:정보시스템연구
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• 제22권1호
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• pp.181-200
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• 2013

Electronic channel of automobile insurance has emerged as an attractive way of lowering costs and saving time to do the transaction for customers. Electronic channel refers to using web sites to find useful information on insurance products, buy automobile insurance, and ask for services related to the insurance. This study suggests a modified model of the UTAUT and examines the factors influencing intention to use electronic channel in the transaction of automobile insurance. Based on 203 responses from potential automobile insurance buyers, the results showed that performance expectancy, effort expectancy, social influence, service expectancy, and security risk are significantly related to intention to use electronic channel. The results also showed that age as a moderator influences the effects of performance expectancy and effort expectancy on intention to use electronic channel. The study results would improve the understanding of the factors to which managers of insurance companies should pay attention in order to increase their sales through electronic channel.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 I
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• pp.234-237
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• 2003

The accuracy of channel estimation significantly affects the performance of coherent OFDM receiver. It is desirable to employ a good channel estimator while requiring low implementation complexity. In this paper, we propose a channel estimator that employs a simple two-dimensional (2-D) moving average (MA) filter as the channel estimation filter. The optimum tap size of the 2-D MA FIR filter is analytically designed in the time and frequency domain in association with the channel condition and pilot signal to interference power ratio. The analytic results can be applied to the design of adaptive channel estimator. Finally, the performance of the proposed channel estimator is verified by computer simulation.

• Journal of Advanced Marine Engineering and Technology
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• 제33권5호
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• pp.738-745
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• 2009

Underwater acoustic communication has multipath error because of reflection by sea-level and sea-bottom. The multipath of underwater channel causes receive signal to make error floor. In this paper, we propose the underwater communication system using various channel coding schemes such as RS coding, convolutional code, turbo code and concatenated code for overcoming the multipath effect in underwater channel. As shown in simulation results, characteristic of multipath error is similar to that of random error. So interleaver has not effect on error correcting. For correcting of error floor by multipath, it is necessary to use strong channel codes like turbo code. Turbo code is one of the iterative codes. And the performance of concatenated codes including RS code has better performance than using singular channel codes.

• 한국통신학회논문지
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• 제33권11C호
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• pp.868-873
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• 2008

본 논문에서는 수직 자기기록 채널에서 연집에러에 따른 LDPC(low density parity check) 부호의 성능을 분석한다. 수직 자기기록 채널에서 연집에러가 발생하면 수신부에서는 채널상태정보(channel state information)를 통하여 연집에러 부분을 알아낸 후 채널검출기의 연판정(Log Likelihood Ratio) 값을 0으로 초기화하는 방법을 사용한다. 패리티 검사 행렬은 부호율이 0.94인 (4336,4096)와 (8672,8192)를 사용한다. 그리고 채널 검출기는 연산량이 적은 SOVA(soft output Viterbi algorithm)를 사용한다.

• 대한전자공학회논문지
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• 제27권4호
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• pp.484-490
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• 1990

In speech coding scheme, because information bits have different error sensitivities over channel errors, the channel coder for combining with speech coding should be realized by the variable coding rate considering the bit importance of speech information bits. In realizing the 4 kbps channel coder for 12kbps speech, this paper have chosen the channel coding method by analyzing the hard-decision post-decoding error rate of RCPC(Rate Compatible Punctured Convolutional) codes and bit error sensitivity of 12 kbps speech. Under the coherent QPSK and Rayleigh fading channel, the performance analysis has showed that 10dB gain was obtained in speech SEGSNR by 4-level uneuqal error protection, which was compared with the caseof no channel coding at 7dB channel SNR.

• 전자공학회논문지D
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• 제35D권12호
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• pp.53-58
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• 1998

다결정 실리콘 박막 트랜지스터를 이용한 회로의 성능 향상을 위하여 새로운 구조의 4-terminal buried channel poly-Si TFT(BCTFT)를 설계하고 제작하였다. BCTFT는 moderate 도핑이 된 buried channel을 이용하므로 기존의 다결정 실리콘 TFT보다 ON-전류와 전계 효과 이동도가 n-형과 p-형 소자 각각 5배와 10배 향상되었다. BCTFT는 moderate 도핑된 buried 채널과 counter 도핑된 body 사이의 junction 공핍에 의하여 캐리어의 이동이 억제 되므로 OFF-전류가 증가하지 않았다.

• Journal of Information Processing Systems
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• 제13권4호
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• pp.1029-1042
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• 2017

A joint channel estimation and data detection technique for a multiple input multiple output (MIMO) wireless communication system is proposed. It combines the least square (LS) training based channel estimation (TBCE) scheme with sphere decoding. In this new approach, channel estimation is enhanced with the help of blind symbols, which are selected based on their correctness. The correctness is determined via sphere decoding. The performance of the new scheme is studied through simulation in terms of the bit error rate (BER). The results show that the proposed channel estimation has comparable performance and better computational complexity over the existing semi-blind channel estimation (SBCE) method.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권10호
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• pp.4034-4053
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• 2015

In order to meet various requirements for transmission quality of both primary users (PUs) and secondary users (SUs) in cognitive radio networks, we introduce a channel bonding mechanism for PUs and a channel reservation mechanism for SUs, then we propose a novel spectrum allocation strategy. Taking into account the mistake detection and false alarm due to imperfect channel sensing, we establish a three-dimensional Markov chain to model the stochastic process of the proposed strategy. Using the method of matrix geometric solution, we derive the performance measures in terms of interference rate of PU packets, average delay and throughput of SU packets. Moreover, we investigate the influence of the number of the reserved (resp. licensed) channels on the system performance with numerical experiments. Finally, to optimize the proposed strategy socially, we provide a charging policy for SU packets.

• 한국통신학회논문지
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• 제34권12B호
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• pp.1498-1505
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• 2009

In centralized control sensor network, tree-based multi-channel communication overcomes the recurrent channel switching and makes possible to transfer data simultaneously from different sources. In our paper, we propose a greedy algorithm named as NIT (Non-Intersecting Tree) that the trees can avoid inter-tree interference. We also propose channel switching technique by which trees can avoid link failure or area blocking due to external interference locally without rerunningthe algorithm and without interrupting the whole network. At first we applied our algorithm for a random topology and then we evaluate the performance of the network using NS-2 simulator. The results show that with the increasing of channel the throughputand delivery ratio are increased significantly. We got better performance than a using a recent proposed Tree-based Multi-Channel Protocol (TMCP).

• 한국정보통신학회논문지
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• 제12권2호
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• pp.260-268
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• 2008

본 논문에서는 MCVoD system의 VoD Server Channel 할당 기법 변경을 통한 성능향상에 대해 논하고, 이에 따른 MCVoD system의 전체 성능을 분석하도록 한다. 또한 시뮬레이션을 통해, 동일한 VoD Server Channel 할당 기법을 사용하는 타 VoD system과 성능을 비교해봄으로써, VoD Server 및 Interchange Agent의 동시 사용에 따른, MCVoD system성능을 평가한다.