• Journal of Distribution Science
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• v.16 no.1
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• pp.47-58
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• 2018

Purpose - China has become the world's largest market of Korean culture goods. However the distribution and information channel from which Chinese consumers can access to Korean contents remains under-explored. This study aimed to investigate Chinese consumers' information accessing behavior. Research design, data, and methodology - We collected the sample of 800 customers who are exposed to Korean Wave in China. Regression analysis is used to confirm the relationships in the research model. Results - The results showed that official channels such as state owned sites still play a significant role, Chinese consumers prefer to use unofficial channels and the private SNS is the most popular one. It is also found that users with low interests in Korean contents prefer offline/indirect channels while people who are highly immersed into Korean culture and spend longer time on it tend to favor online/unofficial channels. The results confirms that there are some users' characteristics such as gender, age, income and experience of visiting Korea are relevant to explain their propensity to select distribution and information channels for Korean contents. Conclusions - The study enables managers to develop the more effective distribution channel strategies according to the different target consumer groups.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.267-271
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• 2006

In this paper, we use the OFDM transmission channel model applied to the MIMO antennas considering spatial propagation property to evaluate and investigate the ergodic capacity of the channel. Specially, we have applied our results to 3GPP TR 25.99 V1.1.0 case 1 LOS off channel description and calculated ergodic capacity with parameters, cluster angle spread and angle of arrival(AOA). Our results show that as the cluster angle spread increase the channel capacity increase until 35 degree, but for more than 35 degree channel capacity does not improved.

• Journal of electromagnetic engineering and science
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• v.7 no.2
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• pp.83-90
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• 2007

In this paper, the formulation of the protection ratio based upon a composite fade margin and availability is newly presented for the detailed planning of frequency coordination in the microwave relay system network, and computed results for co-channel and adjacent channel protection ratios are illustrated over an actual system with 6.2 GHz. It is shown that the protection ratio to assure a quality of service can be expressed in terms of the composite fade margin, noise-to-interference ratio, net filter discrimination, and system parameters. In addition, the net filter discrimination, depending upon the transmitter spectrum mask and the overall receiver filter characteristic, has been examined to investigate the effect of the adjacent channel protection ratio caused by the adjacent channel interference. Regarding simulated results for 6.2 GHz, 60 km, 64-QAM, and N/I=6 dB at the bit error rate of $10^{-6}$, composite fade margin and co-channel protection ratio yield 25.14 and 50.3 dB, respectively. Also, the net filter discrimination of 26.5 dB and the adjacent channel protection ratio of 23.8 dB are obtained at the first adjacent channel of 30 MHz. The proposed method provides some merits in view of a comprehensive and practical application with more detailed and various system parameters needed to access the criteria for making the proper frequency coordination.

• Journal of electromagnetic engineering and science
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• v.11 no.2
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• pp.128-132
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• 2011

In interference tolerance based spectrum sharing systems, primary receivers (PRs) are protected by a predefined peak or average interference power constraint. To implement such systems, cognitive radio (CR) transmitters are required to adjust their transmit power so that the interference power received at the PR receivers is kept below the threshold value. Hence, a CR-transmitter requires knowledge of its channel and the primary receiver in order to allocate the transmit power. In practice, it is impossible or very difficult for a CR transmitter to have perfect knowledge of this channel state information (CSI). In this paper, we investigate the impact of imperfect knowledge of this CSI on the performances of both a primary and cognitive radio network. For fixed transmit power, average interference power (AIP) constraint can be maintained through knowledge of the channel distribution information. To maintain the peak interference power (PIP) constraint, on the other hand, the CR-transmitter requires the instantaneous CSI of its channel with the primary receiver. First, we show that, compared to the PIP constraint with perfect CSI, the AIP constraint is advantageous for primary users but not for CR users. Then, we consider a PIP constraint with imperfect CSI at the CR-transmitter. We show that inaccuracy in CSI reduces the interference at the PR-receivers that is caused by the CR-transmitter. Consequently the proposed schemes improve the capacity of the primary links. Contrarily, the capacities of the CR links significantly degrade due to the inaccuracy in CSI.

• Journal of information and communication convergence engineering
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• v.16 no.2
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• pp.72-77
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• 2018

This paper presents a novel channel capacity maximization method for a distorted $2{\times}2$ line-of-sight (LOS) multiple-input multiple-output (MIMO) link. A LOS MIMO link may be distorted by the influence of environmental factors such that the channel capacity of the LOS MIMO link may be degraded. By using the proposed method, the channel capacity of a distorted $2{\times}2$ LOS MIMO link can be the same as that of the ideal $2{\times}2$ LOS MIMO link. The proposed method employs an additional receiver antenna to maximize the channel capacity. In contrast to a $3{\times}2$ LOS MIMO link, a receiver circuit for a third receiving antenna is not necessary. Hence, the receiver for the proposed method is much simpler than that for a $3{\times}2$ LOS MIMO link. We determine the optimal position of the additional receiver antenna analytically. Simulation results show that the channel capacity can approach the ideal using the proposed method.

• Journal of Distribution Science
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• v.19 no.12
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• pp.23-32
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• 2021

Purpose: By integrating multiple separate online, offline distribution channels, omnichannel distribution has modernized and revolutionized the retailing sector. Omnichannel distribution supports firms by delivering seamless shopping experiences for customers throughout all touchpoints of the shopping journey. This paper aims at exploring the impact of channel integration quality on customer experience and patronage intentions in the omnichannel distribution context. Research design, data and methodology: An online survey was taken with 351 omnichannel experienced shoppers by utilizing the structured questionnaire. The partial least square-structural equation modeling (PLS-SEM) and Smart PLS software were employed to analyze and test proposed hypotheses. Results: The findings reveal that channel integration quality dimensions including breadth of channel-service choice, transparency of channel-service configuration, content consistency, and process consistency, play crucial roles in the customer shopping experience. The perceived compatibility has been influenced by the integrated interactions in which content consistency and process consistency. The findings also demonstrate the positive and direct impact of perceived compatibility on customer experience, and both factors have substantial effects on customers' patronage intentions. Conclusions: This study sheds light on the literature on channel integration quality, omnichannel retailing experience and customer patronage. In addition, this study provides practical implications for omnichannel retailers in enhancing customer experience and patronage.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.3
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• pp.219-230
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• 2022

In implementing a robust automatic target recognition(ATR) system with synthetic aperture radar(SAR) imagery, one of the most important issues is accurate classification of target variants, which are the same targets with different serial numbers, configurations and versions, etc. In this paper, a deep learning network with channel attention modules is proposed to cope with the recognition problem for target variants based on the previous research findings that the channel attention mechanism selectively emphasizes the useful features for target recognition. Different from other existing attention methods, this paper employs the channel attention modules without dimensionality reduction along the channel direction from which direct correspondence between feature map channels can be preserved and the features valuable for recognizing SAR target variants can be effectively derived. Experiments with the public benchmark dataset demonstrate that the proposed scheme is superior to the network with other existing channel attention modules.

• ETRI Journal
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• v.45 no.6
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• pp.952-962
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• 2023

In this study, a space-time transmission scheme is proposed to tackle the limitations of channel estimation with orthogonal pilot information in colocated multiple-input multiple-output systems with several transmitting and receiving antennas. Channel information is obtained using orthogonal pilots. Channel estimation introduces pilot heads required to estimate a channel. This leads to bandwidth insufficiency. As a result, trade-offs exist between the number of pilots required to estimate a channel versus spectral efficiency. The detection of data symbols is performed using the maximum likelihood decoding method as it provides a consistent approach to parameter estimation problems. The moment-generating function of the instantaneous signal-to-noise ratio is used to drive an approximate expression of the symbol error rate for the proposed scheme. Furthermore, the order of diversity is less by one than the number of receiver antennas used in the proposed scheme. The effect of the length of a pilot sequence on the proposed scheme's performance is also investigated.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.325-329
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• 2007

The mobile and multimedia service on wireless network have been leaded from the improvement of telecommunication techniques. A typical multimedia service, a video transmission usually requires larger bandwidth than voice transmission. Many channel allocation algorithms for Orthogonal Frequency Division Multiple Access (OFBMA) to use resources more efficiently, Previous channel allocation algorithms have developed with an assumption that the data traffic is constant bit rate (CBR). However, existing algorithms are not suitable to video traffic because it usually generates a variable bit rate (VBR) traffic. In this paper, we proposed a new channel allocation algorithm called a queue-based channel allocation. it is more suitable to transmit the video traffics. Also, a problem are notified in case of realtime generated video traffic and a corresponding heuristic solution was proposed.

• Journal of the Korean Operations Research and Management Science Society
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• v.22 no.4
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• pp.173-182
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• 1997

In this paper, an efficient dynamic channel assignment scheme is suggested, which consists of two types of channel allocation strategies : ordinary channel allocation strategy and channel reallocation strategy. An analysis on the handoff probabilities of handoff and new calls is also performed, and using the analyzed handoff probability, the presented scheme is compared with other existing schemes in terms of three types of blocking probabilities- new call blocking probability, handoff call blocking probability, and network blocking probability (incomplete service probability). Simulation results show that the presented scheme significantly reduces those blocking probabilities over the existing schemes. Furthermore, the scheme has much smaller number of reallocation than other schemes.