• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.9
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• pp.1117-1122
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• 2019

In this paper, a power allocation scheme is proposed to improve the fairness of user data rates in downlink non-orthogonal multiple access systems with one base station and two users. In particular, the power allocation scheme is presented to maximize the fairness of average user data rates assuming independent Rayleigh fading channels, where the fairness maximization is achieved when the average user data rates are equal. For the fairness evaluation, hence approximate expressions for the average user data rates and the average sum date rate of the proposed scheme are provided by using high signal-to-noise ratio approximation. Through simulation investigation, the derived approximate expressions for the average data rates are verified, and it is shown that the proposed scheme is superior to the conventional power allocation schemes in terms of the fairness of the average user data rates.

• Journal of The Korea Institute of Healthcare Architecture
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• v.1 no.2
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• pp.39-51
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• 1996

Design scheme drawings of the two major corporate hospitals - Asan Medical Center and Samsung Medical Center - are analysed in the aspect of floor area distributions and their proportions for various users and user-functions. Primary users of hospitals are categorized into three ; patients, employees and others. Then, patient spaces are subdivided into patient private, patient/medical, patient/support staff, patient/nursing, patient/guardian, patient common ; employee spaces into doctors, trainees, doctors common, nurses, support staffs, non-medical staffs, employee common ; others spaces into subcontractors, general publics, non-living, and internal circulation. The purpose of this research is to develop a user-focused insight into hospital spaces and a new method of hospital programming and design.

• Journal of the Korean Society for information Management
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• v.14 no.1
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• pp.207-222
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• 1997

This study is aimed at design and implementation of data format for non-book materials in the field of library user interface. The ba-sic data elements were complied with KORMARC and some amend-ments with detailed expansions were applied for development of the use of at libraries. The data formats of various types of media such as books, audio materials, image data, pamphlets, posters which stored in art library were designed respectively through the use of Graphical User Interface.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.111-114
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• 2019

This paper intends to implement a software that controls TurtleBot 2 remotely. The moving of the robot TurtleBot 2 can be controlled using command control based on Windows 10 IoT core instead of the Robot Operating System (ROS). The implemented software allows the user to move remotely TurtleBot 2 in any specified direction and perform the monitoring such as reading feedback data from the robot. Through TCP/IP and serial communication technology, TurtleBot 2 can successfully receive command control and send feedback to the user. Using C# programming language, two Universal Windows Platform apps (client app and server app) have been implemented to allow communication between the user and TurtleBot 2. The result of this implementation has been verified and tested in an indoor platform.

• Journal of the Korean Home Economics Association
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• v.41 no.8
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• pp.19-31
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• 2003

This study was intended to present the plan for preventing and solving the seriousness of the consumer problem perceived in the e-commerce. For this purpose, 723 questionnaires were distributed to university As a result of analysis, the following findings were obtained: 1) It was found that e-commerce users had higher knowledge of the degree of internet un, the ability to use information on the internet, the disposition of computerization, and e-commerce related consumer than e-commerce non-users. 2) It was found that e-commerce non-users had the higher level of perceived seriousness of the consumer problem than e-commerce users. Especially, it was found that e-commerce non-users had the high level of perceived seriousness of the consumer problem related to the problem of exchange, termination and after-sale nice and the leakage of exchange, termination and after-sale service and the leakage of private information e-commerce user. 3) It was found that university consumers' perceived seriousness of the consumer problem in e-commerce over the internet showed a significant difference in the ability to use information on the internet between e-commerce users and non-users.

• Journal of Information Processing Systems
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• v.17 no.5
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• pp.933-946
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• 2021

In the non-orthogonal multiple access (NOMA) system, multiple user signals on the single carrier are superimposed in a non-orthogonal manner, which results in the interference between non-orthogonal users and noise interference in the channel. To solve this problem, an improved algorithm combining regularized zero-forcing (RZF) precoding with minimum mean square error-serial interference cancellation (MMSE-SIC) detection is proposed. The algorithm uses RZF precoding combined with successive over-relaxation (SOR) method at the base station to preprocess the source signal, which can balance the effects of non-orthogonal inter-user interference and noise interference, and generate a precoded signal suitable for transmission in the channel. At the receiver, the MMSE-SIC detection algorithm is used to further eliminate the interference in the signal for the received superimposed signal, and reduce the calculation complexity through the QR decomposition of the matrix. The simulation results show that the proposed joint detection algorithm has good applicability to eliminate the interference of non-orthogonal users, and it has low complexity and fast convergence speed. Compared with other traditional method, the improved method has lower error rate under different signal-to-interference and noise ratio (SINR).

• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.3
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• pp.221-232
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• 2023

In this paper, we propose a recommendation system based on the latent factor model using matrix factorization, which is one of the most commonly used collaborative filtering algorithms for recommendation systems. In particular, by introducing the concept of creating a list of recommended content and a list of non-preferred recommended content, and removing the non-preferred recommended content from the list of recommended content, we propose a method to ultimately increase the satisfaction. The experiment confirmed that using a separate list of non-preferred content to find non-preferred content increased precision by 135%, accuracy by 149%, and F1 score by 72% compared to using the existing recommendation list. In addition, assuming that users do not view non-preferred content through the proposed algorithm, the average evaluation score of a specific user used in the experiment increased by about 35%, from 2.55 to 3.44, thereby increasing user satisfaction. It has been confirmed that this algorithm is more effective than the algorithms used in existing recommendation systems.

• Journal of the Korea Society of Computer and Information
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• v.18 no.2
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• pp.157-164
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• 2013

Self efficacy is a term used in psychology, roughly corresponding to a person's belief in their own competence. It has been defined as the belief that one is capable of performing in a certain manner to attain certain goals. It is believed that our personalized ideas of self-efficacy affect our social interactions in almost every way. Understanding how to foster the development of self-efficacy is a vitally important goal for positive psychology because it can lead to living a more productive and happy life. The objective of this study is to show difference of the relationship between user and non-user in smartphone by self efficacy. For this purpose, we propose a research model which consists of 3type' self efficacy. For empirical test of this model, the sample data is collected from employee in a company and divided into two groups by user and nonuser. By multi-group analysis, we show two groups are different from each other in the relationship between user and nonuser of smartphone. Results show difference of the relationship smartphone user and non-user's self-efficacy(self-control self-efficiacy and problem difficulty preference).

• Journal of Information Processing Systems
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• v.14 no.5
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• pp.1102-1113
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• 2018

Vibrotactile feedback is widely used in designing non-visual interactions on mobile phones, such as message notification, non-visual reading, and blind use. In this work, novel vibrotactile codes are presented to implement a non-visual text reading system for mobile phones. The 26 letters of the English alphabet are formed in an index table with four rows and seven columns, and each letter is mapped using the codes of vibrations. Two kinds of vibrotactile codes are designed with the actuator's on and off states and with specific lengths (short and long) assigned to each state. To improve the efficiency of tactile perception and user satisfaction, three user experiments are conducted. The first experiment explores the maximum number of continuous vibrations and minimum vibration time of the actuator's on and off states that the human can perceive. The second experiment determines the minimum interval between continuous vibrations. The vibrotactile reading system is designed and evaluated in the third experiment according to the results of the two preceding experiments. Results show that the character reading accuracy reaches 91.7% and the character reading speed is approximately 617.8 ms. Our method has better reading efficiency and is easier to learn than the traditional Braille coding method.

• International journal of advanced smart convergence
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• v.9 no.2
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• pp.68-75
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• 2020

Non-orthogonal multiple access (NOMA) has gained the significant attention in the fifth generation (5G) mobile communication, which enables the advanced smart convergence of the artificial intelligence (AI), the internet of things (IoT), and many of the state-of-the-art technologies. Recently, correlated superposition coding (SC) has been proposed in NOMA, to achieve the near-perfect successive interference cancellation (SIC) bit-error rate (BER) performance for the stronger channel users, and to mitigate the severe BER performance degradation for the weaker channel users. In the correlated SC NOMA scheme, the stronger channel user BER performance is even better than the perfect SIC BER performance, for some range of the power allocation factor. However, such excessively good BER performance is not good for the user-fairness, i.e., the more power to the weaker channel user and the less power to the stronger channel user, because the excessively good BER performance of the stronger channel user results in the worse BER performance of the weaker channel user. Therefore, in this paper, we propose the power splitting to establish the user-fairness between both users. First, we derive a closed-form expression for the power splitting factor. Then it is shown that in terms of BER performance, the user-fairness is established between the two users. In result, the power splitting scheme could be considered in correlated SC NOMA for the user-fairness.