• Journal of Digital Convergence
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• v.14 no.8
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• pp.453-460
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• 2016

This study aimed to compare the systems of ticketing application programs of three major movie theaters, CGV, Megabox, Lotte Cinema, with each other and evaluate the usability, and find problems to figure out user experiences for more convenient mobile ticketing. Experimental subjects with experiences of using apps of the movie theaters were recruited; First, as a primary task, they reserved movie tickets with each of the movie theater apps; Second, they had in-depth interviews with questions based on the model of Creating Pleasurable Interfaces by Stephen Anderson. As a result, users preferred the composition with information in order in overall, in which ticketing process went smoothly. In particular, users were more satisfied with convenient payment applications. Therefore, as an improving way, it is required to design an interface for users to recognize at a glance and a payment system within an app, not to design separate payment system out of the app. I hope this study will help actively conduct researches to maximize the usability in a way to reserve movie tickets through smartphone apps.

• International Journal of Knowledge Content Development & Technology
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• v.1 no.1
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• pp.61-79
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• 2011

This study purposed to discover whether or not academic libraries reflect these changing roles. We selected K University as the research target and surveyed user satisfaction of materials, staff services, facilities, electronic devices, media, and so on. The research findings are as follows: 1) the frequency of library visits of University K was on the high side, 2) the primary purpose of using the academic library was associated with learning or reading, therefore, the most used library spaces were related to that, 3) the most used library materials were 'general books', the most unused were 'reference books', 4) the most preferred way to obtain needed materials when failing to find wanted materials was 'Contact librarian'. A similar phenomenon occurred in terms of facility use, 5) university K's users were usually satisfied with the loan policy, 6) the rate of users who don't know whether there is user education was very high, the rate of users who have no experience with user education was extremely low. These research findings can be referenced by library management to improve libraries' service quality and take advantage of complex spatial configurations.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.10
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• pp.4661-4680
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• 2016

Cognitive radio (CR) technology is an effective solution to the spectrum scarcity issue. Collaborative spectrum sensing is known as a promising technique to improve the performance of spectrum sensing in cognitive radio networks (CRNs). However, collaborative spectrum sensing is vulnerable to spectrum data falsification (SSDF) attack, where malicious users (MUs) may send false sensing data to mislead other secondary users (SUs) to make an incorrect decision about primary user (PUs) activity, which is one of the key adversaries to the performance of CRNs. In this paper, we propose a coalition based malicious users detection (CMD) algorithm to detect the malicious user in CRNs. The proposed CMD algorithm can efficiently detect MUs base on the Geary'C theory and be modeled as a coalition formation game. Specifically, SSDF attack is one of the key issues to affect the resource allocation process. Focusing on the security issues, in this paper, we analyze the power allocation problem with MUs, and propose MUs detection based power allocation (MPA) algorithm. The MPA algorithm is divided into two steps: the MUs detection step and the optimal power allocation step. Firstly, in the MUs detection step, by the CMD algorithm we can obtain the MUs detection probability and the energy consumption of MUs detection. Secondly, in the optimal power allocation step, we use the Lagrange dual decomposition method to obtain the optimal transmission power of each SU and achieve the maximum utility of the whole CRN. Numerical simulation results show that the proposed CMD and MPA scheme can achieve a considerable performance improvement in MUs detection and power allocation.

• Journal of the Korean Society for Library and Information Science
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• v.31 no.2
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• pp.95-119
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• 1997

The purpose of this study is to examine the relationships among the factors affecting unanswered reference/information service and to suggest alternative steps which would overcome the unsatisfactory outcome in reference/information service policy. A questionnaire on the quality of reference/information service was developed to survey librarians and users in 10 different private and national university libraries. About half of 500 responses indicated dissatisfaction with the reference/information service and 10 variables were eventually identified as the primary factors which have significant relationships with users's satisfaction. Collection variables were identified as major factors associated with the unanswered service but the analysis of each factor's influence on a reference/information transaction has shown that there exist significant relationships among variables of librarian and environmental variables and the users' satisfaction. Tiered or non-tiered reference/information service showed positive relationships with collection and environmental factors.

• The Journal of the Korea Contents Association
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• v.19 no.2
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• pp.438-449
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• 2019

This study explored the perception of internet media credibility and influencing factors among college students who are routine users of internet-based media. Media literacy competences are of primary interest among others in that users' media literacy such as information evaluation, critical understanding of media, and information sharing are assumed to be related to media credibility. The results of analysis revealed critical understanding ability to be statistically significant and consistently influencing factor. Users with more critical view on media ownership, represented reality, commercial intention of media seemed less likely to trust internet media. Whereas media use motive for information was found to be a strong predicting factor, motive for pleasure showed no relationship with credibility. Based on the findings, suggestions for new research and limitations of the study were discussed.

• Knowledge Management Research
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• v.24 no.4
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• pp.63-85
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• 2023

This study aims to identify the primary user group in the growing metaverse space based on the increased interest during the COVID-19 era. It also aims to explore the predictive factors for metaverse adoption. To predict online activities, the study examined user purposes, motivations, and relevant demographic factors as predictive variables through model analysis. The data from the Korean Media Panel Survey were used, and a two-stage analysis with the Heckman two-stage sample selection model was conducted to predict metaverse users. The analysis revealed that the key factors influencing metaverse adoption were offline activities, openness, OTT usage, and purchasing of paid content. Moreover, in the second stage model, openness, gender, and paid content purchases were identified as significant variables for increasing metaverse usage time. These results indicate that understanding metaverse users is essential in the context of the rising interest in online activities during the COVID-19 era and can provide valuable insights for metaverse platform-related companies and developers.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.5
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• pp.542-547
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• 2014

When a primary user transmits over some frequency band assigned to it, most of its transmission power tends to be concentrated in the band but a small portion of it spreads into the adjacent bands. Thus the false alarm probability for the adjacent bands can be higher than expected, even though no primary users are active in the bands. A previous work evaluated the effects of the adjacent channel leakage on the performance of an energy detection based spectrum sensing but it did not take into account the fading phenomenon. In this paper, we analyze the effects of the adjacent channel leakage on an energy detection based spectrum sensing scheme in terms of detection probability and false alarm probability in a fading environment.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.2
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• pp.184-191
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• 2017

This paper presents cluster based hybrid spectrum sensing system for M2M services. For each cluster, secondary nodes within the transmission radius of the primary node use hard decision method through local spectrum sensing to determine whether the primary node exists. And the other secondary nodes and the secondary nodes having poor radio channel conditions judge the existence of the primary node through the soft decision method of the values obtained by performing the cooperative spectrum sensing. In the proposed hybrid spectrum sensing system, the performance according to the number of secondary nodes is analyzed with the conventional system over Rayleigh fading channel. As the number of cooperative sensing users increased to 2, 3 and 4, the cluster error probability decreased to 0.5608, 0.5252 and 0.4001 at SNR of -10[dB] respectively. Since the proposed system uses less overhead traffic, it is found that it is more effective in terms of frequency usage than the conventional system using soft decision-soft decision and soft decision-hard decision methods.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.1
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• pp.58-71
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• 2019

This paper proposes architecture of a cognitive radio engine platform and the allowable frequency channel reasoning method that enables acquisition of the allowable channels for the military tactical network environment. The current military tactical wireless communication system is increasing need to secure a supplementary radio frequency to ensure that multiple wireless networks for different military wireless devices coexist, so that tactical wireless communication between the same or different systems can be operated effectively. This paper presents the allowable frequency channel reasoning method based on cognitive radio engine for realizing DSA(Dynamic Spectrum Access) as an optimal available frequency channel. To this end, a case-based allowable frequency channel reasoning method for cognitive radio devices is proposed through modeling of primary user's traffic status and calculation of channel occupancy probability. Also through the simulation of the performance analysis, changing rate of collision probability between the primary users' occupancy channel and the available channel acquisition information that can be used by the cognitive radio device was analysed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.16 no.9
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• pp.3172-3193
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• 2022

Cognitive radio-simultaneous wireless information and power transfer (CR-SWIPT) has attracted much interest since it can improve both the spectrum and energy efficiency of wireless networks. This paper focuses on the resource sharing between a point-to-point primary system (PRS) and a multiuser multi-antenna cellular cognitive radio system (CRS) containing a large number of cognitive users (CUs). The resource sharing optimization problem is formulated by jointly scheduling CUs and adjusting the transmit power at the cognitive base station (CBS). The effect of accessing CUs' spatial channel correlation on the possible transmit power of the CBS is investigated. Accordingly, we provide a low-complexity suboptimal approach termed the semi-correlated semi-orthogonal user selection (SC-SOUS) algorithm to enhance the spectrum efficiency. In the proposed algorithm, CUs that are highly correlated to the information decoding primary receiver (IPR) and mutually near orthogonal are selected for simultaneous transmission to reduce the interference to the IPR and increase the sum rate of the CRS. We further develop a spatial correlation-based resource sharing (SC-RS) strategy to improve energy sharing performance. CUs nearly orthogonal to the energy harvesting primary receiver (EPR) are chosen as candidates for user selection. Therefore, the EPR can harvest more energy from the CBS so that the energy utilization of the network can improve. Besides, zero-forcing precoding and power control are adopted to eliminate interference within the CRS and meet the transmit power constraints. Simulation results and analysis show that, compared with the existing CU selection methods, the proposed low-complex strategy can enhance both the achievable sum rate of the CRS and the energy sharing capability of the network.