• Journal of The Korean Association of Information Education
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• v.10 no.1
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• pp.93-104
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• 2006

The purpose of this study is to examine the effects of GLAS(Guided-Learner Adaptable Scaffolding) strategies in web-based collaborative learning environments. Through the extensive literature reviews, web-based collaborative learning environments considering GLAS types were developed. 93 sixth graders were selected from a elementary school in Seoul, and they learned in the web-based system for 4 weeks. The results revealed that the impact of scaffolding on transfer of learning, cognitive overload by reflective scaffolding, learning motivation affected intrinsic scaffolding.

• International journal of advanced smart convergence
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• v.6 no.3
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• pp.29-37
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• 2017

The current behavior recognition system don't match data formats between sensor data measured by user's sensor module or device. Therefore, it is necessary to support data processing, sharing and collaboration services between users and behavior recognition system in order to process sensor data of a large capacity, which is another formats. It is also necessary for real time interaction with users and behavior recognition system. To solve this problem, we propose fog cloud based behavior recognition system for human body sensor data processing. Fog cloud based behavior recognition system solve data standard formats in DbaaS (Database as a System) cloud by servicing fog cloud to solve heterogeneity of sensor data measured in user's sensor module or device. In addition, by placing fog cloud between users and cloud, proximity between users and servers is increased, allowing for real time interaction. Based on this, we propose behavior recognition system for user's behavior recognition and service to observers in collaborative environment. Based on the proposed system, it solves the problem of servers overload due to large sensor data and the inability of real time interaction due to non-proximity between users and servers. This shows the process of delivering behavior recognition services that are consistent and capable of real time interaction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.11
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• pp.2527-2532
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• 2013

There coexist various access network for mobile terminals, such as mobile phones, smart phones, and tablet PC, in mobile and wireless network. In these circumstance, the network traffic overload unexpected causes the service degradation or discontinuity. To solve this problem, we consider a off-loading route selection by a cloud server which monitors traffic volume and selects an appropriate route. With our proposed scheme, it is possible for the EPC network with untrusted WLAN access networks to operate efficiently to a trusted service level. Also, an optimal handover with satisfying service requirements could be achieved by the proposed offload scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.8C
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• pp.801-809
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• 2005

This paper proposes a new algorithm for improving the performance of the spatial filter which is the most important part of deinterlacing methods. The conventional edge-based algorithms are not satisfactory in deciding the exact edge direction which controls the performance of the interpolation. The proposed algorithm much increases the performance of the intrafield interpolation by finding exact edge directions based on the binary image. Edge directions are decided using 15 by 3 local window to find not only more accurate but also many low-angle edge directions. The proposed interpolation method upgrades the visual quality of the image by alleviating the misleading edge directions. Simulation results for various images show that the proposed method provides better performance than the existing methods do.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.249-255
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• 2014

RFID system is used in several fields such as traffic and access control. The study about RFID security is actively progressed as security threat has been increased. This paper suggests matrix-based authentication protocol. And we analyze the safety of authentication protocol and compares the effectiveness of the protocol with other authentication protocols. The suggested authentication protocol secures from wiretapping attack, replay attack, and spoofing attack, and reduces overload of back-end database so that has efficient performance.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.9
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• pp.189-193
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• 2013

In this paper, in order to predict and prevent electrical fires that occur in the power system, we measured the informations of electric power, and then proposed a system to predict the electrical fire using these informations. To this end, we analyzed the correlations for over-current, overload and overheating. These states are caused by the grounding current and the leakage current, and are the main causes of an electrical fire. Use these correlations to derive the derivative of the fuzzy rules for membership function. The designed algorithm was simulated by utilizing the informations of the actual power of the switchgear-panel.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.1
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• pp.27-38
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• 2013

Word-of-mouth (WOM) communication (traditionally important in consumption) is expanding its influence into cyber space and is playing an important role in online shopping. Consumers who use online shopping might not readily make purchasing decisions due to information overload, lack of accurate product recognition, and the distrust of commercial information. Subsequently, people use WOM communication for a mutual interchange with others who share common concerns, interests, and purposes. This study examines the consumer characteristics, perceived risk on online shopping and benefits of online shopping according to WOM behavior that may significantly affect consumer actions. Factor analysis, t-test, one-way ANOVA, cluster analysis, and Chi-square analysis were used for statistical analysis to identify the differences in consumer characteristics. Online WOM behavior consumers purchased more various items than offline WOM behavior consumers; however, the most influential purchasing factor was price regardless of WOM behavior. Offline WOM behavior consumers have shown higher perceived online shopping risks and benefits.

• Journal of KIISE:Information Networking
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• v.28 no.3
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• pp.435-446
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• 2001

In this paper, a new fairness control method is proposed to distribute DQDB-SR (Distributed-Queue Dual-Bus with Slot Reuse) network bandwidth fairly to all stations on client-server environments. By using an access limit that follows a characteristic of client-sever load patterns and a bandwidth borrowing and returning mechanism, the proposed mechanism imparts fairness bandwidth control capability to DQDB-SR. To implement the proposed mechanism, we find the optimal placement of erasure nodes that maximizes network capacity for DQDB-SR, and calculate the access limit. At overload conditions, simulation results show that the proposed mechanism does not deteriorate network throughput, and outperforms other fairness control mechanisms in a success rate and an average packet transfer delay.

• ETRI Journal
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• v.19 no.3
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• pp.186-201
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• 1997

In this paper, a home location register (HLR) for CDMA mobile communication system (CMS) is introduced. It stores the mobile station (MS) subscribers locations and supplementary service information. Call processing procedures for HLR are developed to receive and store subscriber's location coming from mobile exchange (MX) during the location registration, and to transfer subscriber's location and supplementary service information to the MX during the mobile-terminated call setup. For fast call processing by increasing database access speed, a memory-resident database management system is devised. For Easy and secure HLR operation, administration and maintenance functions and overload control mechanisms are implemented. Designed HLR hardware platform is expandable and flexible enough to reallocated software blocks to any subsystems within the platform. It is configurable according to the size of subscribers. An authentication center (AC) is developed on the same platform. It screens the qualified MS from the unqualified. The calls to and from the unqualified MS are rejected in CMS. To authenticate the MS, the AC generates a new authentication parameter called "AUTHR" using shared secret data (SSD) and compared it with the other AUTHR received from the MS. The MC also generates and stores seed keys called "A-keys" which are used to generate SSDs. The HLR requirements, the AC requirements, software architecture, hardware platform, and test results are discussed.

• The Journal of Information Systems
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• v.24 no.1
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• pp.147-168
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• 2015

Why people reduce or stop using social network services(SNS), which are regarded as a mean of relationship and communication, unlike the early trend? To explain the phenomenon, this study tries to predict psychological decision making process of users from perspectives of cognitive dissonance theory. From this perspective, this study attempted an integrative approach that reflected 'User's literacy' indicating the ability of individuals to use SNS, and 'negative mass media influence' such as media reports on side effects or the bad experiences of acquaintances, along with the 3 factors used in the SNS Prior research. This study conducted an empirical analysis by surveying 256 facebook users, and the major findings are as follows:- First, Social-overload, complexity, uncertainty and negative media influence are significantly affect dissonance on the use of SNS. Second, Dissonance on the use of SNS significantly affects the behavior that possibly reduces and limits the use of SNS. In other words, the users who have experienced psychological dissonance respond passively by avoiding the use of SNS to resolve the dissonance. Third, the moderating effect of User's literacy wasn't a significant. This study presents a clue to understand psychological decision making process of use of SNS and a guideline for establishing practical strategies. In addition, it is important to note that this study contributes to expansion of theoretical discussion about usage.