• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.123-140
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• 2011

In this paper, we propose an Energy Efficient Media Access Control (EE-MAC) protocol for wireless sensor networks. The proposed scheme is designed to save power consumption and guarantee quality-of-service for real-time traffic. EE-MAC uses the superframe structure which is bounded by the transmission of a beacon frame and can have an active and an inactive portion. The active period is divided into the contention free period (CFP) for real-time traffic transmission and the contention access period (CAP) for non-real-time traffic transmission. We propose the exclusively allocated backoff scheme which assigns a unique backoff time value to each real-time node based on bandwidth allocation and admission control. This scheme can avoid collision between real-time nodes by controlling distributed fashion and take effect a statistical time division multiple access. We also propose the algorithm to change the duty cycle adaptively according to channel utilization of media depending on network traffic load. This algorithm can prolong network lifetime by reducing the amount of energy wasted on idle listening.

• Journal of the Korea Society of Computer and Information
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• v.6 no.4
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• pp.138-145
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• 2001

In this paper, we propose fuzzy closed BCMP queueing network model for the performance evaluation of distributed processing system. Which has the ambiguous service requirements of job to servers and service rates of server according to network environments. This model can derive the measures for system Performances using fuzzy mean value analysis which can process the fuzzy factors. Computer simulation has been performed for verifying the effectiveness of derived equations of performance evaluation according to service requirements of job and the numbers of clients.

• Journal of Korea Game Society
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• v.12 no.3
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• pp.11-24
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• 2012

Primarily working on SNS(Social Network Service) platform, the SNG(Social Network Game) utilizes friends and neighbors for invitation and play. Based on the value model of HCI, this paper purports to discover how functional, hedonic, social and personal values predict the continuous usage intention and satisfaction of SNG in a smartphone. Hypothesis testing through structural equation modeling shows that hedonic and functional values affect satisfaction and intention to use of SNG while social and personal values do not. This result implies that fun and easy interface are more important to the success of SNG service than social networking motivation.

• Journal of Information Management
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• v.42 no.4
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• pp.225-242
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• 2011

With the development of the IT and internet, companies try to use Blogs, Twitter, Facebook, smart phone for their marketing and customer relationship management. What is called social media marketing appear and it lead to new value creation to the company. However, until now most of libraries in Korea didn't have much interest in marketing and PR. In recent, libraries are starting to be interested in marketing and social network service. Library try to use social network service for marketing. This research introduces the various cases and status of using social network service for marketing in Korea and international library field, analyzes these cases from a marketing perspective. Finally, this research suggests the considerations and successful strategy for using social media marketing in library field.

• Journal of Information Technology Applications and Management
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• v.15 no.4
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• pp.221-245
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• 2008

Recently, mobile internet technologies are enabling the possibility of radically new computing services which can share information and communicate with others on the move. In this situation, prior studies have attempted to identify of what factors make people use mobile internet. However, prior researches focused on investigating the factors affecting users' adoption to Mobile Internet. In order to offer beneficial materials to mobile internet companies, we investigated important factors to increase mobile users' value from the viewpoints of customer. In particular, this study was progressed how characteristics of mobile contents affect users' intrinsic attributes and how perceived users' network effects affect users' value in the mobile computing environments. To empirically test proposed hypotheses, we have analyzed 285 survey data gathering from mobile internet users and verified hypotheses by using SEM (structural equation modeling). Based on the results of this study, we found that content accessibility and content quality have significant impacts on users' intrinsic attributes such as perceived usefulness and perceived enjoyment. In addition, this study also revealed that perceived usefulness and perceived enjoyment were positively related to users' emotional value. Moreover, this study found that perceived users' network effects could affect users' monetary value by mediating expected benefits. Based on our findings, we can understand that this perspective can provide a deeper understanding of the mobile users' value adoption by bridging the gap between mobile internet studies and actual practice.

• The KIPS Transactions:PartC
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• v.10C no.1
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• pp.111-118
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• 2003

Network reliability means network ability which perform normal operation of network components within defined time period, on the other hand, network survivability is the index of normal operation in nerwork failure. In occurrence of network failure, network operator is interested in the measurement of network survivability, but, in a view of subscribers, it is more interested in how many subscribers are out of service and how long the out of service state lasts. In this paper, a service outage evaluation model fitted for telecommunication network in Korea is proposed, which measures the impacts of subscribers in case of network failure which induces a service outage. The outage evaluation result of "Mobile to Land" service outage which has 30.000 subscribers affected for 30 minutes is 2.5. This value is 5 times larger than that of the same service outage which has 10,000 subscribers affected for 30 minutes, i.e, the impact of subscribers in the former case is 5 times larger than that of the latter case. If 30,000 subscribers have isolated in "Mobile to Land," "Local Mobile to Mobile" service for 30 minutes by the exchange out of order in PCS network, then the evaluation result of this service outage will be 3.75.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.2
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• pp.41-47
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• 2012

MANET has vulnerable structure on security owing to structural characteristics as follows. MANET consisted of moving nodes is that every nodes have to perform function of router. Every node has to provide reliable routing service in cooperation each other. These properties are caused by expose to various attacks. But, it is difficult that position of environment intrusion detection system is established, information is collected, and particularly attack is detected because of moving of nodes in MANET environment. It is not easy that important profile is constructed also. In this paper, conformal predictor - support vector machine(CP-SVM) based intrusion detection technique was proposed in order to do more accurate and efficient intrusion detection. In this study, IDS-agents calculate p value from collected packet and transmit to cluster head, and then other all cluster head have same value and detect abnormal behavior using the value. Cluster form of hierarchical structure was used to reduce consumption of nodes also. Effectiveness of proposed method was confirmed through experiment.

• Journal of information and communication convergence engineering
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• v.4 no.4
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• pp.141-146
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• 2006

In these days, wireless data services are becoming ubiquitous in our daily life because they offers several fundamental benefits including user mobility, rapid installation, flexibility, and scalability. Moreover, the requests for various multimedia services and the Quality of Service (QoS) support have been one of key issues in wireless data communications. Therefore the research relative to Medium Access Control (MAC) has been progressing rapidly. Especially a number of QoS-aware MAC schemes have been introduced to extend the legacy IEEE 802.11 MAC protocol which has not guaranteed any service differentiation. However, none of those schemes fulfill both QoS features and channel efficiency although these support the service differentiation based on priority. Therefore this paper studies a novel MAC scheme, referred to as Enhanced Distributed Coordination Function with Network Adaptation (EDCF-NA), for enhancements of both QoS and medium efficiency. It uses a smart factor denoted by ACK rate and Network Load Threshold (TH). In this paper, we study how the value of TH has effect on MAC performance and how the use of optimal TH pair improves the overall MAC performance in terms of the QoS, channel utilization, collision rate, and fairness. In addition, we evaluate and compare both the performance of EDCF-NA depending on several pairs of TH and the achievement of various MAC protocols through simulations by using Network Simulator-2 (NS-2).

• The Korean Journal of Food And Nutrition
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• v.28 no.3
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• pp.358-368
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• 2015

The study is focused on analyzing the SNS using characteristics of the people surveyed, as for the SNS acceptance channel of the food service corporations, accounted voluntarily for 71%. The SNS food service information regarding information of menu, location of store, price, coupon, taste evaluation, event, promotion, reservation and store atmosphere was researched. The most preferred information sharing for SNS food service were researched and found Facebook, blog and others in increasing order. The most preferred media to obtain SNS food service information were smart phone, desktop computer and others. The result of verifying differences in the perceived ease of use were also evaluated according to the food service corporation of SNS using characteristics of the people and was found: the longer period of SNS use, longer was access time: more number of visiting times, higher perceived ease of use. As for the difference in the perceived service value: longer the period of SNS use, more preferred was the blog: the more number of visiting times, the higher perceived service value. As for the difference in the online mouth-to-mouth intention: longer the period of SNS use, longer was access time: the more number of visiting times, the higher online mouth-to-mouth intention. Therefore, these research results provide useful implications in the working-level aspects such as providing basic data and the academic approach of the study, when the food service corporations establish marketing strategies through SNS.

• International Journal of Computer Science & Network Security
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• v.22 no.9
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• pp.396-402
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• 2022

The study deals with the problem of the formation of pre-service teachers' reflective skills in information environment. The role of reflection as a mechanism of formation of a modern teacher's self-consciousness was cleared up. The technology of formation of pre-service teachers' reflective skills was characterized and tested. The main stages of the technology were: a motivational and cognitive stage, a problematic and practical stage, and a reflective and operational stage. The substantiated pedagogical conditions of formation of pre-service teachers' reflective skills were adhered. The criterial and evaluative characteristics of the formation of pre-service teachers' reflective skills were worked out: components (reflection of personal conformity, reflection of the psychological and pedagogical barriers, reflection of professional growth); criteria (criterion of consistency, criterion of difficulty, criterion of potential); indicators (cognitive-evaluative, value-motivational, activity-creative). The levels of formation of pre-service teachers' reflective skills (insufficient level, acceptable level, and optimum level) were determined. The analysis of students' surveys showed the effectiveness and expediency of using the technology of formation of pre-service teachers' reflective skills in the process of professional training.