• Korean Management Science Review
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• v.23 no.3
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• pp.133-156
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• 2006

The ubiquitous technology, leading the stream of change in telecommunication market, makes VoIP a foundation technology to enter NGN era. With this trend in mind, VoIP providers try to satisfy customer needs and invest on R&D in order to survive in this emerging market. The critical issues to VoIP providers are two fold the first one is to find out the quality attributes of Internet telephony service; and the second one is to assess the impact they have on customer satisfaction, customer loyalty and customer performance. In this study, we attempt to empirically answer the above two issues employing SEM (structural equation modeling) and AHP (analytic hierarchy process), and suggest strategic guidelines for successful deployment of Internet telephony service.

• Journal of the Korea Society of Computer and Information
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• v.21 no.10
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• pp.55-62
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• 2016

In this paper, we present indoor localization technologies using the bluetooth signal categorizing them into proximity based, triangulation based and fingerprinting based technologies. Then we provide localization accuracy improvement algorithms such as moving average, K-means, particle filter, and K-Nearest neighbor algorithms. We define important performance issues for indoor localization technologies and analyze recent technologies according to the performance issues. Finally we provide experimental results for correlation between RSSI and distance. We believe that this paper provide wise view and necessary information for recent localization technologies using the bluetooth signal.

• Journal of Information Technology Applications and Management
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• v.16 no.4
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• pp.223-244
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• 2009

Defense R&D is an essential investment for the national security. Recently our nation has also begun to initiate a number of defense R&D projects. As a lot of fund and resources are allocated to these projects, we need to identify which projects to initiate and then how to manage these projects well. Though there have been a number of studies on R&D projects in commercial sector, there are only a few studies in defense R&D sector. Moreover, these existing defense R&D studies mainly deal with the former issues, which are occurring at the stage of project planing. We are more concerned with project management issues, such as how to manage projects that had already been evaluated to undertake at the planning stage. Specifically our study aims to identify project management factors leading to the success of defense R&D projects. Results of the empirical analysis indicate that management support, user-driven requirements management, and project planning capability are key elements for project performance.

• International Commerce and Information Review
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• v.9 no.4
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• pp.307-328
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• 2007

This paper discusses some requirement issues of future global e-trade. Korea has been making lots of efforts on e-trade promotions and many research results support that the performance of e-trade should be increased. There are still many unsolved issues as well as future demands in this area. In this paper, we propose some e-trade requirements for next generation and those are e-trade governance, collaboration enhancement among trading participants, the utilization of e-trade documents repository, the expansion of global e-trade network, and e-trade intelligence just to name a few. For each requirement, we propose some research topics as well as practical implications for improving the performance of global e-trades. One can find some useful thoughts for the future research based on the propositions made by this paper.

• Journal of Communications and Networks
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• v.14 no.4
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• pp.385-395
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• 2012

This paper tackles the problem of generating shared secret keys based on the physical characteristics of the wireless channel. We propose intelligent quantization mechanisms for key generation, achieving high secret bits generation rate. Moreover, some practical issues affecting the performance of the key generation mechanism are deeply investigated. Mainly, we investigate the effects of delay and mobility on the performance and we enhance the key generation mechanism accordingly. As a result, this paper presents a framework towards robust key generation from multipath wireless channels.

• Journal of the Korea Society of Computer and Information
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• v.22 no.8
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• pp.47-53
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• 2017

In this paper, we present open hardware platforms for Internet of Things (IoTs) emphasizing their strengths and weaknesses. We introduce six representative platforms, Raspberry PI, Arduino, Garileo, Edison, Beagle board and Artik. We define important performance issues for open hardware platforms for IoTs and analyze recent platforms according to the performance issues. We present recent research project using open hardware platforms introduced in this paper. We believe that this paper provide wise view and necessary information for open hardware platforms for Internet of Things (IoT).

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.6
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• pp.1327-1342
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• 2010

With the wide deployment of biometric authentication systems, several issues pertaining security and privacy of the biometric template have gained great attention from the research community. To resolve these issues, a number of biometric template protection methods have been proposed. However, the design of a template protection method to satisfy four criteria, namely diversity, revocability and non-invertibility is still a challenging task, especially performance degradation when template protection method is employed. In this paper, we propose a novel method to generate a revocable minutiae-based fingerprint template. The proposed method consists of feature extraction from fingerprint minutiae pairs, quantization, histogram binning, binarization and eventually binary bit-string generation. The contributions of our method are two fold: alignment-free and good performance. Various experiments on FVC2004 DB1 demonstrated the effectiveness of the proposed methods.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.1
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• pp.65-73
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• 2007

To consider business-based requirements beyond the existing roles of water supply, water utilities need enough methodology to integrate lots of related issues and to introduce effective decision-makings. On these grounds, this study modeled and simulated water business system using system dynamics approach. It is expected that formalised model can describe the actual system structurally and statistically, help utilities to predict their business performance and make decisions to solve chronic issues. Moreover, the case study of Y city gave political measures objectively and practically.

• Journal of the Korea Society for Simulation
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• v.12 no.2
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• pp.55-62
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• 2003

The explosive Increase of wireless networks and the advancement of mobile devices lead to the expansion of mobile environment. In accordance with the development of mobile environment, the need to use mobile database is increased sharply, and also it accompanies the related problems. The current mobile database system is based on the centralized method from which a synchronized server manages multiple mobile database management system to synchronize. From this mobile system architecture, several kinds of problems can be detected such as the management of synchronization issues between mobile databases and the transaction management issues. Furthermore, the current mobile database management system does not consider any solution on the fault tolerance. To solve those problems, this paper proposes the mobile agent-based mobile database management system. The proposed system provide high confidence and efficiency by enhancing the network efficiency and fault tolerance through the mobile grouping.

• Journal of the Korea Society of Computer and Information
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• v.22 no.1
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• pp.33-40
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• 2017

In this paper, we introduce commercial indoor navigation systems being deployed and serviced in many fields of industry focusing on their indoor positioning technologies. Indoor positioning technology is a technology that locates people or targets in the interior of a building. To do that, it utilizes radio waves such as WiFi, and bluetooth, magnetic fields, or other sensory information from smart phones. We present indoor navigation systems categorizing them into their indoor positioning technologies. We define important performance issues for indoor positioning technologies and analyze them according to the performance issues. We believe that this paper provide wise view and necessary information for recent indoor navigation systems.