• Journal of Korea Society of Digital Industry and Information Management
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• v.19 no.1
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• pp.91-107
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• 2023

With the recent expansion of the commerce ecosystem, a large number of user evaluations have been produced. Accordingly, attempts to create business insights using user evaluation data have been actively made. However, since user evaluation can change after the user experiences the product, it is difficult to say that the analysis based only on reviews immediately after purchase fully reflects the user's evaluation of the product. Moreover, studies conducted so far on user evaluation have overlooked the fact that the length of time a user has used a product can affect the user's product evaluation. Therefore, in this study, we build a model that predicts the direction of change in the user's rating after use from the user's rating and reviews immediately after purchase. In particular, the proposed model reflects the product's period of use in predicting the change direction of the star rating. However, since the posterior information on the duration of product use cannot be used as input in the inference process, we propose a structure that utilizes information about the product's period of use using an auxiliary classifier. As a result of an experiment using 599,889 user evaluation data collected from the shopping platform 'N' company, we confirmed that the proposed model performed better than the existing model in terms of accuracy.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.283-288
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• 2006

In the future television broadcasting a flood of information from various sources will not always be welcomed by everyone. The need of accessing specific information as required is becoming a necessity. We are interested to make the life of television consumer easier by providing an intelligent television set which can adaptively proposed certain shows to the viewer based on the user historical consumed shows. The TV watching history data consists of TV program titles with their respective genres, channels, watched times and durations, etc. The method proposed is by utilizing Hidden Markov Model (HMM) to model the user preference of kind of genres the viewer will watch based on recorded genres of several weeks time. We take watching schedule from 6 PM to midnight as boundary. The range thus divided into 3 independent time band of 2 hours each resulting in 3 time bands from 6 PM to 8 PM, 8 PM to 10 PM, and lastly 10 PM to midnight. Each time band will be represented by an HMM. From each HMM we can generate a sequence of predicted genre that the user will probably watch during corresponding time-band. Our approach assumes that the user shows a consistent behavior of watching pattern in week to week basis and during the moment of watching TV. To asses the method performance experiment is conducted using real data collected from December 2002 to May 2003. Some user's data are selected and based on that predictions are made. The resulting predictions are then compared with the actual user's history. The experiment shows satisfactory result for user with middle to high consistent behavior level.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1638-1641
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• 2004

Many walking stands, and assisting tools have been developed for the people with low-limb disability to prevent diseases from bedridden state and to help them walk again. But many of those equipments require user to have some physical strength or balancing ability. In our last research, we developed walking assist system for the people with lower-limb disability. With the system, user can be assisted by actuators, and do not have to worry about falling down. The system adapted the unique closed links structure with four servomotors, three PICs as controller, and four limit switches as HMI (human man interface). We confirmed the adaptability of the system by the experiment. In this research, Muscle Stiffness Sensor was tested as the advanced HMI for walking assist system, and confirmed the adaptability by the experiment. As Muscle Stiffness Sensor can attain the muscle activity, user can interface with any device he want to control. Experimental result with Muscle Stiffness sonsor showed that user could easily control the walking assist system as his will, just by changing his muscle strength.

• Journal of the Ergonomics Society of Korea
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• v.32 no.1
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• pp.69-75
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• 2013

Objective: This study proposes an alarm display and compares it with the one(alarm tile display) widely used in main control rooms(MCRs) of nuclear power plants. Background: Catching up with the rapid development of computer technologies, advanced MCRs has been required. Using modern technologies of computers and visual displays, we have a lot of potential to improve user performance and satisfaction as well as safety in MCRs. Method: The alarm bar display has been proposed to reduce some potential problems of the alarm tile display in this study. Human factors evaluations were conducted to compare both types of displays. Two interfaces of bar alarm and tile alarm were simulated on the desktop computer for the user-involved experiment. Eight students participated in the experiment with the within-subject design. Results: The alarm bar was slightly better in terms of situation awareness, and preferred to understand alarm dynamics. The alarm tile was slightly or significantly better in other measures. Conclusion: Both alarm displays have their own advantages and disadvantages. Therefore, combining benefits of both displays can be used to optimize the design of alarm displays. Application: The proposed display is expected to compensate the existing displays for certain purposes.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.11a
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• pp.191-194
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• 2003

As internet commerce grows, many company has begun to use a CF (Collaborative Filtering) as a Recommender System. To achieve an accuracy of CF, we need to obtain sufficient account of voting scores from customers. Moreover, those scores may not be consistent. To overcome this problem, we propose a new recommendation scheme using binary user-item matrix, which represents whether a user purchases a product instead of using the voting scores. Through the experiment regarding this new scheme, a better accuracy is demonstrated.

• Journal of the Ergonomics Society of Korea
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• v.31 no.1
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• pp.15-21
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• 2012

Objective: We propose empathy as a user research method for service design. Background: We argue that empathy will enable user researchers to go beyond the conceptual knowledge to the design knowledge of user experience. Method: We tested our hypothesis by conducting an experiment in which subjects were required to propose solutions to improve the experience of a family member of a patient hospitalized in an emergency department. Results: We found that the subjects who empathized with the family member of a patient tended to suggest the solutions based on design knowledge rather than the solutions based on conceptual knowledge compared to the subjects who did not empathize. Conclusion: Data support our hypothesis that empathy enables people to focus on design knowledge rather than conceptual knowledge. Application: These findings provide practical implications for user researchers in service design.

• ETRI Journal
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• v.10 no.1
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• pp.3-13
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• 1988

With the contunuing trends towards an information based society, telecommunications services are becoming an integral part of social activities. So, emphasis on ISDN is growing rapidly and placed on supporting integrated services delivery of different levels to the end user. The end user’s perception of an integraged services delivery(in particular, ISDN services) should reflect three interrelated capabilities, ISDN access capabilities and ISDN network capabilities. For turning the ISDN concept of above capabilities into reality, we have implemented the experimental system on user-network interfaces, which are three kinds of implementations in user access arrangements, namely basic access, intermediate rate multiplexed access and primary rate multiplexed access. Through these implementations, NTE(Network Terminating Equipment) is used for single basic access [2B+D], IMUX (Intermediate rate Multiplexer) for 4 basic accesses [4X(2B+D)] and PMUX(Primary rate Multiplexer) for [10/12 X (2B+D)]. This paper describes the outlines of system features on user access equipments, system architectures of testbed and experiment result of each access arrangements.

• International Journal of Computer Science & Network Security
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• v.22 no.2
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• pp.250-260
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• 2022

Mobile Banking Applications (MBAPs) is one of the recent fads in mobile trading applications (Apps). MBAPs permit users to execute exchanges of money and many more whenever it might suit them; however, the primary issue for mobile banking Apps is usability. Hardly any investigation analyzes usability issues dependent on user's age, gender, exchanging accomplices, or experience. The purpose of this study is to determine the degree of usability issues, and experience of mobile banking users. The survey employs a quantitative method and performs user experiment on 240 participants with six different tasks on the application's interface. The post experiment survey is done with concerning participants. On the other hand, banking experts and Information Technology (IT) expert's group is also involved after the experiment. Expert's opinions about existing mobile banking Apps and suggestions for improving usability of MBAPs are collected through physical means (like questionnaire and interview) and online means like Google form. After that comparison of the opinions of users and experts about MBAPs is performed. The experimentation measures the tasks usability of various mobile banking apps with respect to its effectiveness, efficiency, trustfulness, learnability, memorability and satisfaction. The usability testing was led at different Universities and the outcomes acquired show that there are privacy and trust issues with their mobile banking apps. There is also a gap between users and experts which should be minimized by applying customized usability models, modes concept like other application software and also by adding complete features of banking in MBAPs. It will benefit mobile banking apps users, developers and usability engineers by providing user-friendly which are up to the mark of user's requirements.

• Korean Management Science Review
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• v.22 no.1
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• pp.27-46
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• 2005

As the electronic commerce has grown dramatically, visiting the Internet shopping malls is accepted as one of our daily life. Despite many studies about user acceptance of the Internet shopping malls, it still remains unanswered how the Internet shopping mall's three quality factors such as system qualify, Information qualify, and service quality affect user trust, and eventually user acceptance of the mall. To investigate this issue, we propose a research model in which six external factors such as three qualify factors as well as self-efficacy, subjective norm, and trust have a significant impact on user's attitude and intention to use the mall. After garnering 244 valid questionnaires from users, we analyze them with structural equation modeling. Experiment results show that the Internet shopping mall's three quality factors such as system quality, information qualify, and service quality significantly Influence user trust for the mall, which in turn impacts user's perceived usefulness, attitude toward using the mall. Another external factors such as self-efficacy and subjective norm also influence user's perceived ease of use and perceived usefulness respectively, affecting user's attitude altogether. Implications and further research directions are presented.

• The Journal of the Acoustical Society of Korea
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• v.36 no.1
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• pp.39-48
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• 2017

CDMA (Code Division Multiple Access) is promising medium access control schemes for underwater acoustic sensor networks because of its robustness against frequency-selective fading and high frequency-reuse efficiency. In this paper, we design diversity schemes of underwater CDMA transceiver for the forward and reverse links. User data are multiplexed by Walsh code and a pseudo random noise code acquisition process is added for phase error correction before decoding the user data at the receiver. Then, the diversity reception using equal gain combining and maximal ratio combining is performed in order to minimize performance degradation caused by rich multipath fading of underwater acoustic channel. We evaluated the performance of diversity transceiver through lake experiment, which was performed at Lake Kyungcheon, Mungyeong city using two transmitters and two receivers placed 460 m apart at an average depth of 40 m. The lake experiment results show that user data are recovered with error-free in both of the forward and reverse links.