• Journal of the Korean Society for information Management
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• v.37 no.4
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• pp.151-179
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• 2020

This study explores the potential of using a library chatbot to improve the non-face-to-face digital reference services for academic library users by designing and implementing a library chatbot. Through data analysis, user needs and library services were analyzed, and a scenario was designed by selecting an appropriate development method. For user-friendly interaction, the personality of the chatbot and user interface was designed to evaluate its usability. In addition, the accuracy was verified through the response accuracy evaluation and performance evaluation of the chatbot, and the effectiveness of the chatbot was evaluated through a user satisfaction survey. In order to manage the operation and maintain service quality, the chatbot is improved by monitoring user-chatbot conversations and reflecting user feedback. Based on these findings, recommendations for designing and implementing a library chatbot were made to help improve library reference services.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.25-30
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• 1992

A knowledge based hybrid simulation environment has been established which supports the simulation procedure from the modeling step to the experimentation step by providing various tools, query, and advisory. The knowledge base in the established environment uses the If-Then Rule to transfer the fact input from the user to the act for the execution of the simulation process. Simulation non-experts are the user target and non-specific area is the application target.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.159-166
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• 2013

Recently, because the interest and needs in privacy protection are growing, smartcard-based remote user authentication schemes have been actively studied to provide the user anonymity. In 2008, Kim et al. first proposed an authentication scheme in order to ensure the user anonymity against both external attackers and the remote server and track malicious users with the help of a trusted trace sever. However, in 2010, Lee et al. showed that Kim et al.'s scheme cannot provide the user anonymity against remote server, which is because the server can trace users without any help of the trace server, and then proposed a improved scheme. On the other hand, in 2010, Horng et al. proposed an authentication scheme with non-tamper resistant smart cards, in which the non-tamper resistant smart card means that an attacker may find out secret information stored in the smart card through special data analysis techniques such as monitoring power consumption, to be secure against a variety of attacks and to provide the user anonymity against external attackers. In this paper, we will propose a remote user authentication scheme with non-tamper resistant smart cards not only to ensure the user anonymity against both external attackers and the remote server but also to track malicious users with only the help of a trusted trace sever.

• Proceedings of the Korea Information Processing Society Conference
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• 2016.04a
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• pp.897-899
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• 2016

In recent years, BLE technology has received extensive attention and has been applied to all aspects of life. The existing BLE device has two methods, one is the connection method, and the other is a non-connection method. The representative profile of the connection method is the proximity file. The most typical example of Non-connection method BLE device is a beacon. However, they are both independent and have their own shortcomings. Connection method device can provide service for only one user, others can't use. Security performance of Non-connection method BLE device is poor and the device can't be controlled by the user. In this paper, a combination-mode BLE device profile design scheme is presented, which combines with the previous two methods, and solves the defaults. And We define a dual purpose advertising package that can be used in a normal environment as well as in a disaster environment. Finally, a unidirectional Control idea is proposed. Through performance evaluation, we found that the device has strong stability and low power consumption.

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.78-84
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• 2022

In this paper, to improve further the bit-error rate (BER) performance of the stronger channel user in non-uniform source non-orthogonal multiple access (NOMA) with symmetric superposition coding (SSC), we propose a smart bit-to-symbol (BTS) mapping of SSC. First, the analytical expression for the total allocated power of the proposed BTS mapping scheme is derived, and then we show that the BER of the proposed BTS mapping scheme improves further, compared to that of the existing BTS mapping scheme. Moreover, based on the simulations, the signal-to-noise (SNR) gain of the proposed BTS mapping scheme over the existing BTS mapping scheme is calculated. In result, the proposed BTS mapping could be a candidate scheme for non-uniform source SSC NOMA with the SNR gain.

• Journal of the Korean Data and Information Science Society
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• v.27 no.6
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• pp.1557-1564
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• 2016

Recently, an extended warranty of a system following the expiration of the basic warranty is becoming increasingly popular to the user. In this respect, we suggest a two stage maintenance policy under the non-renewing warranty from the user's point of view in this paper. In the first stage, the user has to decide whether or not to purchase the extended warranty period. And, in the second stage, the optimal replacement period following the expiration of the warranty is determined. Under the extended warranty, the failed system is minimally repaired by the manufacturer at no cost to the user. We utilize the expected cost from the user's perspective to determine the optimal two stage maintenance policy. Finally, a few numerical examples are given for illustrative purpose.

• Journal of the Institute of Convergence Signal Processing
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• v.3 no.2
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• pp.23-29
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• 2002

In this paper we proposed the user identification system using hybrid biometric information and non-contact IC card to improve the accuracy of the system. The hybrid biometric information consists of the face image, the iris image, and the 4-digit voice password of user. And the non-contact IC card provides the base information of user If the distance between the sample hybrid biometric Information corresponding to the base information of user and the measured biometric information is less than the given threshold value, the identification is accepted. Otherwise it is rejected. Through the result of experimentation, this paper shows that the proposed method has better identification rate than the conventional identification method.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.4 no.1 s.6
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• pp.81-88
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• 2005

Cooperation among network users would be possible in a near future, as real time communication between them can be available by telematics. This implies that non-cooperative assumption like Wardrop's principle, which has been widely used so far in network modelling may not be appropriate for route choice problem. So a new principle requires for describing such cooperative case. This paper presents a criterion, which represents cooperative route choice behaviour among network users. With some examples, we compare the non-cooperative principle and the cooperative one presented in this paper. Numerical results from the examples show that the new principle would be better than the existing one.

• ETRI Journal
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• v.41 no.5
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• pp.626-636
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• 2019

A novel algorithm for joint user selection and optimal power allocation for Stackelberg game-based revenue maximization in a downlink non-orthogonal multiple access (NOMA) network is proposed in this study. The condition for the existence of optimal solution is derived by assuming perfect channel state information (CSI) at the transmitter. The Lagrange multiplier method is used to convert the revenue maximization problem into a set of quadratic equations that are reduced to a regular chain of expressions. The optimal solution is obtained via a univariate iterative procedure. A simple algorithm for joint optimal user selection and power calculation is presented and exhibits extremely low complexity. Furthermore, an outage analysis is presented to evaluate the performance degradation when perfect CSI is not available. The simulation results indicate that at 5-dB signal-to-noise ratio (SNR), revenue of the base station improves by at least 15.2% for the proposed algorithm when compared to suboptimal schemes. Other performance metrics of NOMA, such as individual user-rates, fairness index, and outage probability, approach near-optimal values at moderate to high SNRs.

• Journal of Korea Society of Digital Industry and Information Management
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• v.18 no.1
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• pp.115-124
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• 2022

This study analyzed the intention of continuous use of the electronic attendance-absence system. Perceived ease of use, acceptance attitude, and user satisfaction variables were selected to analyze the factors affecting the intention of continuous use. To achieve the purpose of this study, a survey was conducted targeting students who had experience in using the electronic attendance-absence system at K University located in Chungcheongbuk-do. The use environment of the electronic attendance-absence system was non-face-to-face, and the questionnaires answered by 921 students were analyzed. The study results are as follows. First, perceived ease of use and acceptance of the electronic attendance-absence system were found to have a positive effect on user satisfaction. Second, it was found that the learner's perceptual ease, acceptance attitude, and user satisfaction for the electronic attendance-absence system had a positive effect on the intention of continuous use. This study is meaningful in that it identified the intention of continuous use based on the experience of the electronic attendance-absence system in a non-face-to-face environment.