• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1317-1322
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• 2018

In order to complete the AR UI design simply and quickly, the usable factors were studied in this thesis. The primary aim of interface design is to increase the usability. The various factors should be considered together when we evaluate the usability. The idealized usable working model is based on user-centered with the aim of perceiving the interests of users, operating easily and completing targets. In order to ensure the types of usable factors, literature survey method had been used and a total of 85 usable factors had been collected by this survey. To make the usable factors can adapt the augmented reality, the concept of factors should be redefined. We extract the items which is adaptable and user-centered, combine or delete the items that have the same meanings and finally select 25 usable evaluative factors. Then we take HCI professional as the object and collect the data by Heuristic Evaluation. We systematize the usable factors by Principal Component Analysis, and observe the correlation between the usable factors and classify those which have high correlation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.197-199
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• 2016

In this paper, we investigate a market equilibrium in multi-channel sharing cognitive radio networks (CRNs): it is assumed that every subchannel is orthogonally licensed to a single primary user (PU), and can be shared with multiple secondary users (SUs). We model this sharing as a spectrum market where PUs offer SUs their subchannels with limiting the interference from SUs; the SUs purchase the right to transmit over the subchannels while observing the interference limits set by the PUs and their budget constraints. The utility function of SU is defined as least achievable transmission rate, and that of PU is given by the net profit. We define a market equilibrium in the context of extended Fisher model, and show that the equilibrium is yielded by solving an optimization problem, Eisenberg-Gale convex program.

• Journal of the Korean Society of Safety
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• v.34 no.2
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• pp.56-62
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• 2019

Secondary accident is common type of accident which occurs in Korean highway tunnels. Fatality rate of secondary accidents in highway tunnels is six time higher than primary accidents. Video type VMS is a new way of providing information to road users which was recently introduced by Korean government to prevent secondary accidents in highway tunnels. In this study we compared changes in driver's behavior when information is provided by Text type and Video Type VMS. In addition to analyze effects of secondary accident reduction, driving behavior was analyzed based on providing advance information by video type VMS at tunnel entrance. Analysis showed that both text type and video type VMS has similar effect on driver behavior. Video type VMS showed positive effect on driver's behavior to prevent secondary accident when information is provided 1km ahead of accident. Considering there results and the short-term memory characteristics of driver, it was determined that information should be provide at about 650m from the entrance of the tunnel. The results of this study are consistent with the requirement that VMS should be installed at least 500m ahead of tunnel and produce more accurate providing information points. 650m is also appropriate interval for providing information in tunnel to cope with an accident ahead.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.4
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• pp.5-27
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• 2020

This study, as primary research that examines the communication characteristics of the library and the perception of librarians in order to make public libraries a communication space, surveyed the perception of librarians in public libraries and made an attempt to devise activation measures for the communication spaces of the library. As a result, the communication characteristics of the library were derived to be locality, community spirit, and interactivity. In addition, the perception survey found that librarians have positive remarks about the communication spaces of the library. As it shows a high degree of awareness, the library should focus on ways to revitalize communication. First, the direction of communication must be set in order to fulfill library's new role in communication and exchange. Second, it is desirable for the library to free itself from being a quiet space and recreate it as a space for communication. Third, the library needs to exchange and connect with organizations, groups, and gatherings of the community. Fourth, it seems necessary for the library to provide support for the users' independent and voluntary communication and operation of the community.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.2
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• pp.37-52
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• 2005

Traditional access control models like role-based access control model are insufficient in security needs in ubiquitous computing environment because they take no thought of access control based on user's context or environment condition. In these days, although researches on context-aware access control using user's context or environment conditions based on role-based access control are emerged, they are on the primary stage. We present context definitions md an access control model to provide more flexible and dynamic context-aware access control based on role-based access control. Specially, we describe the conflict problems occurred in the middle of making an access decision. After classifying the conflict problems, we show some resolutions to solve them. In conclusion, we will lay the foundations of the development of security policy and model assuring right user of right object(or resource) and application service through pre-defined context and context classification in ubiquitous computing environments. Beyond the simplicity of access to objects by authorized users, we assure that user can access to the object, resource, or service anywhere and anytime according to right context.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.22 no.5
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• pp.1145-1157
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• 2012

Google Android employs a security model based on application permissions to control accesses to system resources and components of other applications from a potentially malicious program. But, this model has security vulnerabilities due to lack of user comprehension and excessive permission requests by 3rd party applications. Broadcast intent message is widely used as a primary means of communication among internal application components. However, this mechanism has also potential security problems because it has no security policy related with it. In this paper, we first present security breach scenarios caused by inappropriate use of application permissions and broadcast intent messages. We then analyze and compare usage patterns of application permissions and broadcast intent message for popular applications on Android market and malwares, respectively. The analysis results show that there exists a characteristic set for application permissions and broadcast intent receiver that are requested by typical malwares. Based on the results, we propose a scheme to detect applications that are suspected as malicious and notify the result to users at installation time.

• International Journal of Computer Science & Network Security
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• v.21 no.2
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• pp.110-119
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• 2021

The Coronavirus or COVID-19 is contagiousness virus that infected almost every single part of the world. This pandemic forced a major country did lockdown and stay at a home policy to reduce virus spread and the number of victims. Interactions between humans and robots form a popular subject of research worldwide. In medical robotics, the primary challenge is to implement natural interactions between robots and human users. Human communication consists of dynamic processes that involve joint attention and attracting each other. Coordinated care involves sharing among agents of behaviours, events, interests, and contexts in the world from time to time. The robotics arm is an expensive and complicated system because robot simulators are widely used instead of for rehabilitation purposes in medicine. Interaction in natural ways is necessary for disabled persons to work with the robot simulator. This article proposes a low-cost rehabilitation system by building an arm gesture tracking system based on a depth camera that can capture and interpret human gestures and use them as interactive commands for a robot simulator to perform specific tasks on the 3D block. The results show that the proposed system can help patients control the rotation and movement of the 3D arm using their hands. The pilot testing with healthy subjects yielded encouraging results. They could synchronize their actions with a 3D robotic arm to perform several repetitive tasks and exerting 19920 J of energy (kg.m².S^-2). The average of consumed energy mentioned before is in medium scale. Therefore, we relate this energy with rehabilitation performance as an initial stage and can be improved further with extra repetitive exercise to speed up the recovery process.

• The Journal of the Convergence on Culture Technology
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• v.7 no.4
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• pp.385-390
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• 2021

This study aims to provide primary data for R&D on rollator-walking frame through researching the usability test of the rollator-walking frame and the effect of rollator-walking frames on the lives of senior citizens. This study surveyed 60 senior citizens living in Sungnam City in South Korea. As the result of the usability test, we can find users' dissatisfaction with the folding, weight, shape of backrest and material of chair. The survey shows that the frequency of outdoor activity is mostly increased by the convenience of product. However, the inconvenience while using facilities, such as elevators or public transportations, gave a significant impact on the decrease in going out experiences. Therefore, for better outside lifestyle of senior citizens, it is important to improve the function of the product, however, we need to make improvement of urban infrastructure.

• Journal of Information Technology Services
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• v.21 no.1
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• pp.163-179
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• 2022

Two dominant phenomena in modern world; population ageing and digitalization, have led public sector organizations to heavily rely on B2C(Business-to-Consumer) mobile applications. Yet, fatal concerns and complaints have often been raised by the mobile application users, notably from social welfare sector. With the continual expansion of digital landscape as well as the growth of life expectancy, usage of mobile applications has become prevalent across the stakeholders involved in social welfare sector. 'Smart Long-Term Care (SLTC)', inter alia, is a primary example of such mobile applications, designed to support Long-Term Residential Care (LTRC) service. The main goal of SLTC is to serve more convenient and practical LTRC service for both caregivers and care receivers. To examine user satisfaction of SLTC mobile application, this study investigates existing challenges and means to improve user satisfaction. Hence, we conducted this study using two methods: in-depth interview and topic modeling. Interestingly, two research outcomes commonly indicated that 5 factors (stability, accessibility, usefulness, responsiveness, and ease of use) were found significant in affecting user satisfaction of SLTC. Our findings suggest that the aforementioned factors can be seen as potential causes of the genuinely low user satisfaction. Eventually, this work will be a stepping-stone to elevate the overall quality level of LTRC service along with the user satisfaction degree of SLTC mobile application.

• Journal of The Korea Institute of Healthcare Architecture
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• v.28 no.1
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• pp.63-74
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• 2022

Purpose: The purpose of this study is to present an evacuation performance analysis model that can derive vulnerable evacuation spaces with considering the movement behavior as per the elderly groups in the event of a fire in a geriatric hospital. Methods: The evacuation characteristics of geriatric hospital users were investigated through the review of precedent studies. First, the occupant conditions and the evacuation scenario were set to analyze a study target hospital. Then, the evacuation simulation was carried out considering the group types and the density of each group. Finally, an evacuation performance analysis model according to the group type was presented based on the simulation results. Results: The results of this study are as follows: (1) The evacuation performance according to the group type is to be clarified through the suggested study model. (2) It is necessary to secure a ramp or an emergency elevator to distribute the evacuation personnel at the design stage because congestion occurs due to collisions between evacuees on the stairs and delays the evacuation time. (3) It is necessary to consider the evacuation stairs and openings of sufficient size by analyzing the frequency of congestion occurrence and the escape routes of occupants in advance to identify the space where the evacuation flow overlaps. Implications: It is expected that the study result is to be used as primary data for studies that consider the elderly and clustering evacuation behavior in the event of a fire in a geriatric hospital.