• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.137-140
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• 2011

A precoding strategy is one of the representative interference management techniques in cognitive radio (CR) network which is a typical interference-limited environment. The interference minimization approach to precoding is an appropriate scheme to mitigate the interference efficiently while it may cause the capacity loss of the desired channel. The precoding scheme for the maximal capacity of the desired channel improves the capacity of the desired channel while it increases the interference power and finally causes the capacity loss of the interfered users. Therefore, we propose a precoding scheme which satisfies these two conflicting goals and manages the interference signal in such an interference-limited environment. The proposed scheme consists of two steps. First, the precoder nulls out the largest singular value of the interference channel to mitigate the dominant interference signal based on the interference minimization approach. Second, the transmitter calculates the sum capacities per mode and selects a mode to maximize the sum capacity. In the second step, each mode consists of the right singular vectors corresponding to the singular values except the largest singular value eliminated in the first step. Simulation results show that the proposed precoding scheme not only efficiently mitigate the interference signal, but also has the best performance in terms of the sum capacity in a MIMO-based CR network.

• Journal of the Korean Society of Propulsion Engineers
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• v.17 no.2
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• pp.114-121
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• 2013

In order to estimate the efficiency of an evaporative heat exchanger having mini channel, the equations to calculate heat exchanger properties, those are air temperatures and water temperatures etc, are derived from the governing equations based on the Navier-Stokes equation, even though there are several assumptions to make problem simplify. There are three heat transfer zones at the mini channel heat exchanger depending on the water condition. So, there are three governing equations and solutions to calculate the properties. As the results of this study, the equations to calculate a saturation point and a dry point are derived to evaluate an evaporative heat exchanger having micro channel. It is supposed to predict and evaluate the performance of a mini channel heat exchanger with evaporation of liquid.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.4
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• pp.1884-1903
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• 2019

Device-to-Device (D2D) communications can provide proximity based services in the future 5G cellular networks. It allows short range communication in a limited area with the advantages of power saving, high data rate and traffic offloading. However, D2D communications may reuse the licensed channels with cellular communications and potentially result in critical interferences to nearby devices. To control the interference and improve network throughput in overlaid D2D cellular networks, a novel channel assignment approach is proposed in this paper. First, we characterize the performance of devices by using Poisson point process model. Then, we convert the throughput maximization problem into an optimal spectrum allocation problem with signal to interference plus noise ratio constraints and solve it, i.e., assigning appropriate fractions of channels to cellular communications and D2D communications. In order to mitigate the interferences between D2D devices, a cluster-based multi-channel assignment algorithm is proposed. The algorithm first cluster D2D communications into clusters to reduce the problem scale. After that, a multi-channel assignment algorithm is proposed to mitigate critical interferences among nearby devices for each D2D cluster individually. The simulation analysis conforms that the proposed algorithm can greatly increase system throughput.

• The Journal of Industrial Distribution & Business
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• v.12 no.3
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• pp.7-19
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• 2021

Purpose: This study aims to examine customer experience toward repurchase intention in offline and online stores and discuss customer satisfaction as a mediator variable. Research design, data, and methodology: This study investigates customer experience that consists of product, customer service, staff service, shopping environment and shopping procedure toward customer satisfaction using Regression Linear. This study also measures customer satisfaction as a mediated variable in the relationship between customer experience and repurchase intention using Sobel Test. Results: Almost all of the customer experience hypothesis is significant toward customer satisfaction, shopping process experience in the context of the online channel to customer satisfaction is not significant. We also found that customer satisfaction can be mediated variable in customer experience toward repurchase intention. Conclusions: Retails who want to make customers feel satisfied to have to make sure that have good resources in improving the product, the customer service is easy to contact to find the solution over customer problem in purchasing product, also develop the staff member skill in functional product knowledge, presentations, and communicating with customers online or offline, the retailer has to create enjoyment and pleasurable customer emotion through the shopping environment and also give seamless shopping experience to their customer in two-channel.

• International journal of advanced smart convergence
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• v.10 no.1
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• pp.142-150
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• 2021

Open-channel SSD is a new type of Solid-State Disk (SSD) that improves the garbage collection overhead and write amplification due to physical constraints of NAND flash memory by exposing the internal structure of the SSD to the host. However, the host-level Flash Translation Layer (FTL) provided for open-channel SSDs in the current Linux kernel consumes host memory excessively because it use page-level mapping table to translate logical address to physical address. Therefore, in this paper, we implemente a selective mapping table loading scheme that loads only a currently required part of the mapping table to the mapping table cache from SSD instead of entire mapping table. In addition, to increase the hit ratio of the mapping table cache, filesystem information and mapping table access history are utilized for cache replacement policy. The proposed scheme is implemented in the host-level FTL of the Linux kernel and evaluated using open-channel SSD emulator. According to the evaluation results, we can achieve 80% of I/O performance using the only 32% of memory usage compared to the previous host-level FTL.

• Journal of Distribution Science
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• v.21 no.3
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• pp.113-121
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• 2023

Purpose: Online distribution channel alludes to the many different digital channels utilized in marketing and distributing goods and services to end users. The present research aims to explore and provide various retail strategy for the success of the art market within online distribution channel. Research design, data and methodology: The current author has conducted and investigate the qualitative textual methodology to take a look at carefully the current and prior literature dataset to achieve the purpose of the present research so that the present author could obtain total 27 relevant prior studies. Results: According to the comprehensive literature investigation, this research has found that there are six kinds of retail strategy for the prosperity of the art market within online distribution channel as follows: (1) Blockchain Technology, (2) Artificial Intelligence (AI), (3) Virtual Reality (VR), (4) Online Market Places, (5) Social Media, and (6) Regulations. Conclusions: The results of this analysis of the relevant literature show that the art market industry needs to adjust to keep up with the quickly shifting landscape of the digital world. In addition, although these technologies can be helpful in addressing difficulties linked to authenticity and transparency, they cannot eliminate the hazards of fraud and misrepresentation.

• Journal of the Korea Fashion and Costume Design Association
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• v.26 no.2
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• pp.129-140
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• 2024

Omni-channel refers to a distribution channel through which consumers can purchase products without time and place constraints through the fusion of existing online and offline stores. Therefore, a study on the effect of the four characteristics of Omni-channel on customer satisfaction and preference was conducted among 350 and 365 Korean and Chinese consumers, respectively on customers of Olive Young and Watson China, representative drug store brands in Korea and China. Analysis was conducted using IBM SPSS 26.0's statistical package program. Frequency analysis, factor analysis, Cronbach alpha, correlation analysis, and regression analysis were performed. As a result of verifying the effect of Omni-channel characteristics on customer satisfaction, it was found that convenience, accessibility, and price fairness had a significant positive (+) effect on customer satisfaction for Korean and Chinese consumers. Customer satisfaction was found to have a significant positive (+) effect on preference. This is because Korean and Chinese consumers generally had high satisfaction and preference for Olive Young and Watsons.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.3
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• pp.945-964
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• 2014

In this paper, we investigate the performance of Signal to Leakage and Noise Radio (SLNR) based user scheduling in uplink of multi-cell with large-scale antenna system. Large antenna array is desired to improve the performance in future system by providing better beamforming capability. However, some studies have found that the signal channel is 'hardened' (becomes invariant) when the antenna number goes extremely large, which implies that the signal channel aware user scheduling may have no gain at all. With the mathematic tool of order statistics, we analyzed the signal and interference terms of SLNR in a homogeneous multicell network. The derived distribution function of signal and interference shows that the leakage channel's variance is much more influential than the signal channel's variance in large-scale antenna regime. So even though the signal channel is hardened, the SLNR-based scheduling can achieve remarkable multiuser diversity (MUD) gain due to the fluctuation of the uplink leakage channel. By providing the final SINR distribution, we verify that the SLNR-based scheduling can leverage MUD in a better way than the signal channel based scheduling. The Monte Carlo simulations show that the throughput gain of SLNR-based scheduling over signal channel based scheduling is significant.

• Journal of Digital Convergence
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• v.10 no.9
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• pp.375-381
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• 2012

If a mobile station requests a channel allocation in its mobile networks, the switching center assigns a channel to a mobile station that belongs to each base station. There are three kinds of channel allocation schemes; a fixed channel allocation, a dynamic channel allocation and a hybrid combination of these two forms. In assigning a good frequency, it is our intention to provide quality service to our customers as well as to use resources efficiently. This paper proposes methods of assigning frequencies that minimize interference between channels and that also minimize the amount of searching time involved. In this paper, we propose an algorithm to per specific equipment, regardless of the number of channels that can be used as a general-purpose system, such as base stations, control stations, central office model is proposed, the existing operators manner similar to the fixed channel allocation based statistics and assigned when the conventional method and the improved method is proposed. Different ways and compared via simulations to verify the effectiveness of the proposed approach.

• The KIPS Transactions:PartA
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• v.10A no.1
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• pp.25-34
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• 2003

Parallel file system solves I/O bottleneck to store a file distributedly and read it parallel exchanging messages among computers that is connected multiple computers with high speed networks. However, they do not consider the message characteristics and performances are decreased. Accordingly, the current study proposes the Hybrid Channel model (HCM) as a message-management method, whereby the messages of a parallel file system are classified by a message characteristic between control messages and file data blocks, and the communication channel is divided into a message channel and data channel. The message channel then transfers the control messages through TCP/IP with reliability, while the data channel that is implemented by Virtual Interface Architecture (VIA) transfers the file data blocks at high speed. In tests, the proposed parallel file system that is implemented by HCM exhibited a considerably improved performance.