• Journal of Information Technology Applications and Management
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• v.24 no.2
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• pp.17-24
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• 2017

Using a sample of 180 managers in small and medium sized organizations in Chungcheong and Southern Gyeonggi Province, we proposed that official communication channel on safety issue will influence managers' safety climate, empathy (safety climate), and eventually occupational accidents. The results supported our hypotheses, showing managers concern about their employees' safety issue when the organization officially emphasize on safety issue. At the same time, it also tells that managers are emphatic on their employees regarding occupational accidents when it comes to safety climate.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1393-1402
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• 2019

This paper proposes a new power flow control method for soft-switched, four channel, five level resonant buck dc-dc converters. These converters have two input channels, which can be supplied from sources with identical or different voltages, and four output channels with arbitrary output voltages. They are specially designed to supply multilevel inverters. The design methodology for their power flow control has been developed considering a general case when the input voltages, output voltages and loads can be asymmetrical. A special emphasize is paid to the limitations and restrictions of operation. The theoretical studies are confirmed by numerical simulations and laboratory tests carried out at various operation points. Exploiting the advantages of the newly proposed power control strategy, the converter can supply five level inverters in dc microgrids, active filters, power factor correctors and electric drives. They can also play an interfacing role in renewable energy systems.

• International Journal of Computer Science & Network Security
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• v.24 no.2
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• pp.95-100
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• 2024

Cyclic Delay Diversity (CDD) is a diversity scheme used in OFDM-based telecommunication systems, transforming spatial diversity into frequency diversity and thus avoiding intersymbol interference without entailing the receiver to be aware of the transmission strategy making the signal more reliable achieving full diversity gain in cooperative systems. Here the analyzation of the influence of CDD-SC scheme in Cognitive Radio Network (CRN) is done with the challenge of overcoming the complication called channel estimation along with overhead in CNR. More specifically, the closed-form expressions for outage probability and symbol error rate are divided under different frequencies among independent and identically distributed (i.i.d.) frequency selective fading channel model i.e., the signal is divided into different frequencies and transmitted among several narrow band channels of different characteristics. It is useful in the reduction of interference and crosstalk. The results reveal the diversity order of the proposed system to be mainly affected by the number of multipath components that are available in the CNR.

• The Journal of Bigdata
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• v.1 no.2
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• pp.35-44
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• 2016

Today there is a fierce competition between social commerce and multi-channel distribution in korea and it is need to do comparative analysis about success factors between social commerce and multi-channel distribution. Unlike the other studies that have only used survey method, this study analyzed the success factors between social commerce and multichannel distribution using text mining techniques. We expect that the result of the study not only gives the practical implication for making the competition strategy of the retailers but also contributes to the diverse extension research.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.4
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• pp.767-783
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• 2013

This paper aims at designing a selective demodulation scheme based on Log-likelihood Ratio threshold (SDLT) instead of the conventional adaptive demodulation (ADM) scheme, by using rateless codes. The major difference is that the Log-likelihood ratio (LLR) threshold is identified as a key factor to control the demodulation rate, while the ADM uses decision region set (DRS) to adjust the bit rate. In the 16-QAM SDLT scheme, we deduce the decision regions over an additive white Gaussian channel, corresponding to the variation of LLR threshold and channel states. We also derived the equations to calculate demodulation rate and bit error rate (BER), which could be proven by simulation results. We present an adaptation strategy for SDLT, and compare it with ADM and adaptive modulation (AM). The simulation results show that our scheme not only significantly outperforms the ADM in terms of BER, but also achieves a performance as good as the AM scheme. Moreover, the proposed scheme can support much more rate patterns over a wide range of channel states.

• Information Systems Review
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• v.4 no.1
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• pp.33-45
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• 2002

With the advance of information technology, it is possible to build the interactive communication channel among relationship participants with low cost, and this channel makes ties between consumers and company by enabling information sharing and exchange. In order to maintain customer relationship, it is necessary to support customer information that includes of-the-customer, for-the-customer, and by-the-customer information. From the three types of customer information, the proper information for the relationship management like the level and type of commitment can be extracted. Customer Information System (CIS), which includes database, communication channel, application program, should be designed to facilitate the customer relationship management. Since lots of investments to information system are required, it is not easy to implement. This paper develops a framework of dynamic customer relationship management and suggests an effective information technology strategy to support that.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.720-725
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• 2009

SDI(Selective Dissemination of Information) is on demand service to inform to the user applies a service after inputting a search strategy, when new information is obtained. This Paper propose the ways to develope the dynamic RSS channel generator for supporting SDI service. The RSS which is a kind of syndication technology enables a part or the whole of the content which it provides from web site to be able to be used in different service. It is protocol to summarize and share various contents on web site. Also, the users register the channel RSS to the RSS aggregator system and recommend it. It can drive to share of knowledge between researchers.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1B
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• pp.99-107
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• 2002

Broadcast disks are suited for disseminating information to a large number of clients in mobile computing environments. In broadcast disks, the server continuously and repeatedly broadcasts all data items in the database to clients without specific requests. The clients monitor the broadcast channel and retrieve data items as they arrive on the broadcast channel. The broadcast channel then becomes a disk from which clients can retrieve data items. In this paper, we propose a cache conscious concurrency control ($C^4$) scheme to preserve the consistency of client transactions, when the values of broadcast data items are updated at the server. $C^4$ scheme is novel in the sense that it can reduce the response time of client transactions with minimal control information to be broadcast from the server. This is achieved by the judicious caching strategy of the clients.

• Journal of Information Technology Applications and Management
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• v.22 no.4
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• pp.105-126
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• 2015

In this study, we investigated the impact of the information richness and reachness on the mobile purchasing and the moderating effect of individual characteristics. We examined the information richness and reachness through SNS information and Push notification of smartphone, respectively. As the moderating variables, we adopted customer's value orientation and innovativeness. In the main-effect model with no moderating variable, both of information richness and reachness showed significant effects on the perceived value of products and purchasing channel. Especially, the impact of information richness was more significant on product awareness, while the impact of information reachness was more significant on channel awareness. In the interaction-effect model with moderating variables, customer's value orientation showed significant moderating effect on the impact of perceived product value. However, customer's innovativeness did not show the significant moderating effect on the impact of perceived channel value. It implies that the impact of information reachness applies to the majority of customers, regardless of her [his] innovativeness. Therefore the organizations might be able to use Push notification to activate the customer's mobile purchasing.

• Transactions of the Korean hydrogen and new energy society
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• v.23 no.5
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• pp.476-483
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• 2012

Proper water management is crucial for the efficient operation of polymer electrolyte membrane (PEM) fuel cell. Especially, for automotive applications, A novel water management that can avoid both membrane dry-out and flooding is a very important task to achieve good performance and efficiency of PEM fuel cells. The aim of this study is to investigate the liquid water behavior on the gas diffusion layer (GDL) surface and in the cathode flow channel of a PEM unit fuel cell under flooding conditions. For this purpose, a transparent unit fuel cell is devised and fabricated by modifying the conventional PEM fuel cell design. The results of water droplet behavior under flooding conditions are mainly presented. The water distributions in the cathode flow channels with cell operating voltage are also compared and analyzed. Through this work, it is expected that the data obtained from this fundamental study can be effectively used to establish the basic water management strategy in terms of water removal from the flow channels in a PEM fuel cell stack.