• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.1
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• pp.20-39
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• 2020

This paper considers a downlink multi-carrier cooperative non-orthogonal multiple access (NOMA) transmission, where no direct link exists between the far user and the base station (BS), and the communication between them only relies on the assist of the near user. Firstly, the BS sends a superimposed signal of the far and the near user to the near user, and then the near user adopts simultaneous wireless information and power transfer (SWIPT) to split the received superimposed signal into two portions for energy harvesting and information decoding respectively. Afterwards, the near user forwards the signal of the far user by utilizing the harvested energy. A minimum data is required to ensure the quality of service (QoS) of the far user. We jointly optimize power allocation, subcarrier allocation, time allocation, the power allocation (PA) coefficient and the power splitting (PS) ratio to maximize the number of data bits received at the near user under the energy causality constraint, the minimum data constraint and the transmission power constraint. The block-coordinate descent method and the Lagrange duality method are used to obtain a suboptimal solution of this optimization problem. In the final simulation results, the superiority of the proposed NOMA scheme is confirmed compared with the benchmark NOMA schemes and the orthogonal multiple access (OMA) scheme.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.1
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• pp.446-465
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• 2015

In this modern era of technology and information, e-learning approach has become an integral part of teaching and learning using modern technologies. There are different variations or classification of e-learning approaches. One of notable approaches is Personal Learning Environment (PLE). In a PLE system, the contents are presented to the user in a personalized manner (according to the user's needs and wants). The problem arises when a new user enters the system, and due to the lack of information about the new user's needs and wants, the system fails to recommend him/her the personalized e-learning contents accurately. This phenomenon is known as cold-start problem. In order to address this issue, existing researches propose different approaches for recommendation such as preference profile, user ratings and tagging recommendations. In this research paper, the implementation of a novel interaction-based approach is presented. The interaction-based approach improves the recommendation accuracy for the new-user cold-start problem by integrating preferences profile and tagging recommendation and utilizing the interaction among users and system. This research work takes leverage of the interaction of a new user with the PLE system and generates recommendation for the new user, both implicitly and explicitly, thus solving new-user cold-start problem. The result shows the improvement of 31.57% in Precision, 18.29% in Recall and 8.8% in F1-measure.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.11
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• pp.4720-4738
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• 2015

Proper management on user-driven virtual circuits (VCs) is essential for seamless operation of virtual networks. The Network Provisioning System (NPS) is useful software for creating user-driven VCs automatically and must take fault management into account for physical layer impairments on user-driven VCs. This paper addresses a user-driven and trusty protection management in an NPS with an open standard Network Service Interface (NSI), as a contribution to show how to implement the user-driven and trusty protection management required for user-driven VCs. In particular, it provides a RESTful web service Interface for Configuration and Event management (RICE) that enable management of a distinguished data and control plane VC status between Network Service Agents (NSAs) in the event of a node or link fault and repair in a domain. This capability represents a contribution to show how network and protection events in a domain can be monitored between NSAs (NPSs with the NSI) in multiple domains. The implemented NPS controls and manages both the primary and backup VC with disjoint path in a user-driven manner. A demonstration to verify RICE API's capability is addressed for the trusty protection in the dynamic VC network.

• Journal of the Korean Data and Information Science Society
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• v.15 no.1
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• pp.11-20
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• 2004

The purpose of this paper was to reveal Service Operation Strategy for the Internet shopping mall based on the types of internet users' market segmentation focus on the internet shopping behavior and e-service quality. In this paper, we examined internet shopping behavior and internet service quality factor depend on the types of internet users' group empirically. The empirical study result identifies the main decision factor depend on the types of internet users' group. On the basis of these result, Service Operation Strategy for the internet shopping mall has been suggested.

• Journal of the Korean Home Economics Association
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• v.43 no.9 s.211
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• pp.1-13
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• 2005

The purposes of this study were to classify internet shopping mall user by their shopping styles and to define the characteristics of the classified individual clusters. Questionnaires were completed by 338 men and women who have used internet shopping malls at lead once during the previous 6 months. The internet shopping styles were classified into 4 clusters after factor analysis and k-means cluster analysis. Cluster I, named 'high brand proneness', can be described as having low score on devotee tendency. Cluster II, named 'high value proneness', is characterized by a high score on seeking substance. Cluster III, called 'steadiness orientation', can be described as having a tow score on seeking trend and substance. Cluster IV, named 'individuality inclination', can be described as having low score on seeking trend. These four clusters differ in terms of socio-demographic and environmental characteristics such as gender, age, educational level, occupation, and internet using time. Theoretical and practical implications are discussed.

• Korean Journal of Health Education and Promotion
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• v.30 no.2
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• pp.1-10
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• 2013

Objectives: The objective of this study was to assess the relationship between internet addiction and health behaviors & mental health among Korean adolescents. Methods: Data from the 2010 Korean Youth Risk Behavior Web-based Survey was analyzed. Using the Korean Internet Addiction Proneness Scale for Youth-Short Form: Self Report developed by the Korean National Information Society Agency in 2008, subjects were classified into 3 groups for internet addiction including general user, potential-risk group, and high-risk group. The health behaviors and mental health were compared among the groups for internet addiction by gender. Results: There was significantly higher prevalence of internet addiction including potential-risk group and high-risk group in boys(14.1%) than in girls(8.8%). There were significant odds ratios of perceived stress, perceived depression, perceived health and happiness, and satisfaction of sleeping in both genders at potential-risk group and high-risk group compared to general user for the internet addiction. The odds ratios of smoking at high risk group, alcohol drinking at potential risk group, eating breakfast at high risk group, and moderate physical activity at both risk groups among boys were significant. Among girls at both risk group, the odds ratios of smoking, alcohol drinking, and eating breakfast were significant. Conclusions: This study reveals a significant association among internet addiction, and health behaviors, and mental health in Korean adolescents.

• Journal of Information Technology Services
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• v.7 no.3
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• pp.1-30
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• 2008

This paper proposes an integrated model of customer loyalty in the context of Internet shopping based on a review of two competing perspectives - transactional and relational views. The research model suggests that the usability and trust associated with an Internet shopping site are key determinants of customer loyalty. In this paper, factors such as promotion, ease of use/navigation, and purchase facilitation are posited as major determinants of usability. Trust, on the other hand, is assumed to be influenced by the quality of communication, social shopping service, and safety level associated with an Internet shopping site. This paper also asserts that the lack of consideration for individual differences is one of the key reasons for the inconsistent and mixed research findings in user acceptance literature. In this regard, the elaboration likelihood model (ELM) is considered to be appropriate referent theory as it may theoretically explain why a particular information technology (IT) related message has varying influences on different adopters. The research model comprising 11 hypotheses was derived from and validated through a survey involving 271 university students. The partial least square(PLS) method was used to test the suitability of the research model and its hypotheses. Overall, the results suggest that the usability and trust associated with an Internet shopping site play an important role in acquiring loyal customers. In particular, the user's Internet shopping involvement is found to moderate the relationship between trust and customer loyalty.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.3
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• pp.480-487
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• 2008

In this paper, we propose a Smart Adapted Service which can manage a schedule automatically. Smart Adapted Service gives a notice beforehand regarding information associated with the schedule, by searching the Internet. If the user has written down the name of goods or food which he wants to buy, Smart Adapted Service finds the most suitable store nearby him using the user's favorite list. The user's favorite list is created by Outlook Web Access System by analysing the schedule and habits of the user. User can access Smart Document System remotely through the Internet using Outlook Web Access System. We developed an Auto AP Roaming System for seamless communication and Smart Document System for arranging the information. We evaluated the system and verified that it is convenient to use and working well.

• International journal of advanced smart convergence
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• v.5 no.3
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• pp.40-46
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• 2016

The internet allows the information to flow at anywhere in anytime easily. Unfortunately, the network also becomes a great tool for the criminals to operate cybercrimes such as identity theft. To prevent the issue, using a very complex password is not a very encouraging method. Alternatively, keystroke dynamics helps the user to solve the problem. Keystroke dynamics is the information of timing details when a user presses a key or releases a key. A machine can learn a user typing behavior from the information integrate with a proper machine learning algorithm. In this paper, we have proposed mini-batch ensemble (MIBE) method which does the preprocessing on the original dataset and then produces multiple mini batches in the end. The mini batches are then trained by a machine learning algorithm. From the experimental result, we have shown the improvement of the performance for each base algorithm.

• International Journal of Internet, Broadcasting and Communication
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• v.8 no.3
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• pp.41-49
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• 2016

Recently, many biometrics-based user authentication schemes for telecare medicine information systems (TMIS) have been proposed to improve the security problems in user authentication system. In 2014, Mishra et al. proposed an improvement of Awasthi-Srivastava's biometric based authentication for TMIS which is secure against the various attacks and provide mutual authentication, efficient password change. In this paper, we discuss the security of Mishra et al.'s authentication scheme, and we have shown that Mishra et al.'s authentication scheme is still insecure against the various attacks. Also, we proposed the improved scheme to remove these security problems of Mishra et al.'s authentication scheme, even if the secret information stored in the smart card is revealed. As a result, we can see that the improved biometric based authentication scheme is secure against the insider attack, the password guessing attack, the user impersonation attack, the server masquerading attack and provides mutual authentication between the user and the telecare system.