• Korea Trade Review
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• v.43 no.1
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• pp.131-152
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• 2018

This study evaluates the potential by Chines region for entry of Korean logistics companies and retailers. The variables affecting e-commerce business and retail sales concerning the Chinese omni-channel market were extracted from a thorough literature review. Empirical analyses for variables based on 31 regions in China were performed. Results show that e-commerce is affected by disposable income and internet traffic and that retail sales are affected by urban and rural population, GRDP and urbanization. In addition, we performed variance decomposition analysis in order to estimate responses of logistics GDP(transport, storage and communication) and the number of Chinese mobile users. Exogenous shocks to logistics GDP and the number of mobile phone users play a strong role in explaining the forecast error of express service variance over time. Based on our results, we suggest 7 potential regions(Guangdong, Jiangsu, Zhejiang, Beijing, Shanghai, Liaoning and Shandong) as well as managerial implications for entry into China for logistics companies and retailers.

• Proceedings of the Korea Information Processing Society Conference
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• 2003.05b
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• pp.1369-1372
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• 2003

가까운 장래에 싼 가격의 블루투스가 여러 가지 이동, 휴대 장치에 내장되어 다양한 응용서비스를 제공할 것이다. 본 논문에서는 공항이나 쇼핑몰 등 사람들이 많이 몰리는 공공장소와 같은 핫스팟(hot spot) 지역에서 블루투스 기지국을 통한 음성서비스 제공을 위하여 다수의 기지국을 유서 LAN으로 협동시켜 각각 기지국별로 따로 제공되던 음성 채널들을 집합화(aggregation) 함으로써 보다 많은 음성 서비스 채널들을 동시에 수용할 수 있는 방법을 제시하고 성능을 분석하였다. 단독으로 동작하는 기지국은 ACL채널을 사용하는 경우 7개까지의 채널 수용이 가능하므로 이상적인 경우에서도 오버랩 영역의 기지국의 개수가 n이면 7n 만큼 채널의 증가가 가능한 반면 협동으로 동작하면 블록킹 율도 개선되면서 집합화된 채널들을 보간(interpolation) 기법을 통한 통계적 사용으로 음성 패킷의 허용 손실 범위 내에서 음성채널의 수를 약 14n 정도까지 확장할 수 있다. 또한 음성전송과 데이터 전송이 혼합 서비스 될 때 수용하는 음성 채널의 수에 따른 데이터 전송지연시간 특성을 분석하였다.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.192-209
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• 2011

This study looked into coping strategies of local terrestrial broadcasting companies in the media market, since the introduction of comprehensive programming channels was confirmed. Local terrestrial broadcasting companies vulnerable to market competitiveness are driven more out to the difficulty of survival in a limited advertising market with the advent of comprehensive programming channel. and Local terrestrial broadcasting receive discriminative application than comprehensive programming channel. They have reverse discrimination in must-carry, broadcasting area, programming regulation, advertisement regulation, broadcasting development fund. Hence, Local terrestrial broadcasting needs diverse countermeasures at difficult media circumstances. Above all, Competitive content reinforcement is desperately needed. That's why content distribution structure needs diversification. And, It is necessary for local terrestrial broadcasting companies to diversify the content distribution system. As a way to expand distribution structure of local broadcasting, the introduction of local programming regulations for total amount will be highlighted in the nationwide network program. The mandatory policy that programs produced by local terrestrial broadcasting companies will be broadcast regularly in prime time through a nationwide network is an example. In addition to developing high content independently, 2nd Multiple channels of distribution is needed. It has to be supplied to various platforms including local broadcasting, SO and etc. In addition, it is necessary to activate regional co-production program between local terrestrial broadcasting companies and regions. Time rate between central stations and local terrestrial broadcasting companies must be distributed practically. And also, local terrestrial broadcasting companies in addition to ad revenue model to themselves and their own businesses by expanding the sponsorship to strengthen the competitiveness will have to nurture self-sustaining. Moreover they must have enlarge economy of scale through widen of broadcasting area.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.6
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• pp.487-493
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• 2013

As the spread of smart devices that service variety of content, limited mobile terminal channel assignment problem has intensified. In the channel assignment in mobile networks mobile switching center at the request belongs to each base station allocates the channel to the mobile station. This effectively allocate the limited channels of various methods have been proposed for, in this case a hybrid channel allocation using genetic algorithms UHGA (Universal Hybrid Channel Assignment using Genetic Algorithm) in rural areas or urban areas, such as universal network applied to a variety of environments that the efficiency is verified through simulation.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.4
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• pp.67-73
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• 2002

There have been increased concerns on mobile stratospheric communication system(SCS) for the purpose of advanced service of personal and high speed communication systems. In fact, this SCS is considered and studied for IMT-2000 service by ITU. Although, it is important to make accurate channel model for prediction of the SCS performance, there is no measured channel data in this system. Thus, in this paper, we estimate the performance of SCS bye use of channel model provided by Corazza(2) and modified by You(3). And also, the effects of channel codings on system performance are analyzed by deriving bit error performance based on realistic Rician log-normal fading channel models. The performance results are divided into three kinds of areas with three kinds of elevation angles 20$^\cire$, 45$^\cire$, and 80$^\cire$. And also the effects of forward error correction channel codings on system performance with Hamming(7,4), HCH( IS,7) and convolutional code of constraint length 3 and code rate R=1/2.

• Korean Journal of Remote Sensing
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• v.25 no.2
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• pp.193-203
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• 2009

Snow cover is one of the important parameters since it determines surface energy balance and its variation. To classify snow and cloud from satellite data is very important process when inferring land surface information. Generally, misclassified cloud and snow pixel can lead directly to error factor for retrieval of surface products from satellite data. Therefore, in this study, we perform algorithm for detecting snow cover area with remote sensing data. We just utilize visible reflectance, and infrared channels rather than using NDSI (Normalized Difference Snow Index) which is one of optimized methods to detect snow cover. Because COMS MI (Meteorological Imager) channels doesn't include near infra-red, which is used to produce NDSI. Detecting snow cover with visible channel is well performed over clear sky area, but it is difficult to discriminate snow cover from mixed cloudy pixels. To improve those detecting abilities, brightness temperature difference (BTD) between 11 and 3.7 is used for snow detection. BTD method shows improved results than using only visible channel.

• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.130-138
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• 2000

The paper describes a push system, a broadcasting system in the internet, which is developed for internet and intranet use. In this paper, we carried out research on the method to support the large number of users in the intranet environment. Particularly the paper analyzes the effects on the network traffic according to the number of the user connected to the push system and the frequency of the connections when push servers are distributed over the intranet. Push system described here uses two different kinds of channels, common channel and local channel. Common channel is the channel to be replicated among the push servers in the intranet. This paper shows that the method using the common channel synchronization is efficient in supporting the large number of intranet users. We introduce an algorithm to make the interconnections between channels efficiently amongpush servers distributed over the intranet.

• 한국정보통신설비학회:학술대회논문집
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• 2004.08a
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• pp.302-307
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• 2004

이 논문은 제한된 대역폭을 가진 고정 채널 할당 문제를 유전알고리즘을 이용하여 최적화하는 방법을 제시한다. 또한 이 논문에서는 유전알고리즘의 미세조정 능력 향상을 위해 지역 최적화 방법을 고안하였다. 고정채널 할당 문제를 행렬로 표현하여 지역 최적화 알고리즘에서는 채널을 수평 또는 수직으로 움직임으로써 유전 알고리즘의 성능 향상을 꾀한다. 제안된 방법은 기존의 방법보다 뛰어난 성능 향상을 나타냄을 실험결과에서 보일 것이다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.1
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• pp.215-222
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• 1998

프랙탈을 기반으로 한 칼라 영상 부호화는 영상을 RGB,YIQ나 CMYK와 같은 기본적인 채널로 분리한 후, 각각의 채널을 독립적으로 프랙탈 이진 영상 부호화 기법에 적용함으로써 쉽게 부호화할 수 있다. 그러나 이 방법은 각각의 채널에 대해 부호화를 반복해야 하기 때문에 많은 계산 시간이 필요하다는 단점이 있다. 본 논문에서는 이러한 단점을 개선하기 위하여 국부적 지역 탐색법을 사용하였으며, 압축률 향상을 위해 각 채널마다 사람의 눈에 느껴지는 민감성의 정도가 다른 YIQ 모델을 사용하여 I나 Q 채널보다 Y채널에 더 많은 비트를 할당하였다. 각각의 치역 블록에 대하여 Y채널에 가장 잘 매칭이 되는 정의역 블록을 찾았으며, I와 Q 채널을 위해서는 잘 매칭이 되는 대응 블록을 이용하였다. 따라서 각각의 YIQ채널을 위한 최적의 변환식을 계산하는 과정에서 단지 하나의 기하학적인 변환식(변환과 선택된 정의역 블록의 주소)만이 필요할 뿐이다. 이러한 접근 방법은 기존의 부호화 방법들과 비교해 볼 때 부호화 시간의 단축과 압축률 향상을 동시에 얻을 수 있다.

• Journal of Broadcast Engineering
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• v.3 no.1
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• pp.1-12
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• 1998

8VSB transmission system of American standard and OFDM system of European standard are to be international standards for the transmission of digital terrestrial television. When countries using PAL standard adopt the American 8VSB system which is designed under the circumstance of NTSC system, one of strong interference is the co-channel PAL interference coming from analog PAL signal. In this paper, in order to solve this problem, we classified seven types of PAL system into three groups according to the bandwidth and a new PAL-8VSB system is proposed to reject the co-channel PAL interference by using modified comb filters suitable for each group. By computer simulations of the proposed PAL-8VSB system with the co-channel PAL interference it is confirmed that the proposed comb filter results in the improvement of DIU ratio by about 9 dB.