• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.2
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• pp.974-987
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• 2018

This paper presents a novel and efficient data transmission scheme based on mobile edge computing for the massive IoT environments which should support various type of services and devices. Based on an accurate and precise synchronization process, it maximizes data transmission throughput, and consistently maintains a flow's latency. To this end, the proposed efficient software defined data transmission scheme (ESD-DTS) configures and utilizes synchronization zones in accordance with the 4 usage cases, which are end node-to-end node (EN-EN), end node-to-cloud network (EN-CN), end node-to-Internet node (EN-IN), and edge node-to-core node (EdN-CN); and it transmit the data by the required service attributes, which are divided into 3 groups (low-end group, medium-end group, and high-end group). In addition, the ESD-DTS provides a specific data transmission method, which is operated by a buffer threshold value, for the low-end group, and it effectively accommodates massive IT devices. By doing this, the proposed scheme not only supports a high, medium, and low quality of service, but also is complied with various 5G usage scenarios. The essential difference between the previous and the proposed scheme is that the existing schemes are used to handle each packet only to provide high quality and bandwidth, whereas the proposed scheme introduces synchronization zones for various type of services to manage the efficiency of each service flow. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of throughput, control message overhead, and latency. Therefore, the proposed ESD-DTS is very suitable for upcoming 5G networks in a variety of massive IoT environments with supporting mobile edge computing (MEC).

• The Journal of Information Systems
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• v.28 no.4
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• pp.293-311
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• 2019

Purpose This paper is to make a meta-analysis of the relationship between the social media use and learning performance as well as its potential moderating variables to clarify the differences in research conclusions in existing literatures, and refine the situational and method factors that affect the relationship between them. Methodology Meta-analysis used in this study can combine the quantitative data from different empirical studies, focus on the same research problem, and finally reach a research conclusion. Findings The results show that social media use and learning performance have a moderating positive correlation. The moderating effect test of usage scenarios shows that social media types, usage groups, application platforms and discipline fields have moderating effects on the relationship between social media use and learning performance. The moderating effect test of the research method found that measurement models, data attributes and learning performance indicators also had moderating effects on the relationship between social media use and learning performance.

• Journal of the Korea Convergence Society
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• v.11 no.11
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• pp.63-74
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• 2020

AI products are used 'AI assistants' as embedded in smart phones, speakers, appliances as agents. Studies on anthropomorphism, such as personality, voice with a weak AI are being conducted. Role and function of AI agents will expand from development of AI technology. Various attributes related to the agent, such as user type, usage environment, appearance of the agent will need to be considered. This study intends to categorize interaction factors related to agents from the user's perspective through analysis of concept videos which agents with strong AI. Framework for analysis was built on the basis of theoretical considerations for agents. Concept videos were collected from YouTube. They are analyzed according to perspectives on environment, user, agent. It was categorized into 8 attributes: viewpoint, space, shape, agent behavior, interlocking device, agent interface, usage status, and user interface. It can be used as reference when developing, predicting agents to be commercialized in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.8C
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• pp.731-741
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• 2009

Optical repeater is often installed at the isolated area. Spatial separation makes it possible to reduce the inter-code interference when secondary scrambling codes are used for traffic connected through repeater. In this paper, we propose five secondary scrambling code usage scenarios with the aids of optical repeater to maximize the user capacity. In order to evaluate the performance, dynamic system level simulation is performed. We also propose a base station-repeater switching where each active users can change access points by comparing the channel condition from base station and repeater thorough secondary common pilot channel (S-CPICH) signal to noise-interference ratio (SINR). Moreover, primary-secondary scramble code replacing scheme is proposed which replaces secondary scramble code with primary scramble code when a call using primary scramble code is ended and its corresponding OVSF code is available to users using the secondary scramble code

• Journal of the Korean Society of Clothing and Textiles
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• v.32 no.7
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• pp.1046-1055
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• 2008

The purpose of this study is to investigate the effects of product variables(i.e., fashionability, brand fame) and situational variables(i.e., time constraint, usage occasion) on the internet browsing behavior (i.e., prepurchase search; ongoing search for products, stores, fashion trends, promotions, and post-purchasing information) for fashion products. This study developed hypothetical scenarios based on the factorial design of the two independent variables for the survey with a questionnaire. All items in the questionnaire were measured on a six-point scale. By convenience sampling and on-line survey, a total of 209 usable responses were used for further analyses. The results show as follows; firstly, respondents more intensively browse for information search on products, stores and fashion trends when the style of browsing products is trendy. Secondly, whether the fashion products have a famous brand name or not has a significant influence on browsing behavior for stores and fashion trends information search. Thirdly, time constraint is found to influence significantly on respondents' browsing for promotions information search. Lastly, occasion for product worn shows a significant influence on browsing behavior for stores and fashion trends information search. The managerial implications are provided based on findings.

• 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.

• Journal of Korean Academy of Nursing
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• v.38 no.1
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• pp.83-91
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• 2008

Purpose: The purpose of this study was to test the validity of a modified clinical performance examination (CPX) for preclinical students in nursing. Method: 70 nursing students in their second semester of the junior year at C University participated in CPX. Scenarios and checklists were developed by our research team from September to October 2005. Six stations were organized. Evaluation included physical examination of a patient with lung cancer, education on usage of a metered dosage inhaler, and lobectomy postoperative care. Students were randomly assigned to a station. Result: There was a difference in the CPX scores according to stations. The agreement of scoring between trained faculty members and SPs was more than moderate (r=.647). The correlation between the CPX score and the average grade in the previous semester and between the CPX score and the average grade of a paper and pen test of the pulmonary system of adults was low (r=.276; r=.048). Conclusion: Traditional CPX is generally recommended, however, modified CPX is appropriate for preclinical students in the current Korean Nursing school setting if there are additional scoring systems to balance the testing level at each station.

• Journal of the Korean housing association
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• v.27 no.6
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• pp.57-64
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• 2016

Life-long housing refers to housing units whose performance is certified by the head of a Life-long Housing certification authority with respect to durability, variability and ease of repair. Since life-long housing should be able to meet residents' demands for changes in living space, the space of the housing should be able to be varied by using a dry construction method, instead of a wet construction method. For life-long housing to be approved, the installation of infill systems that life-long housing certification standards is needed. At present, apartment houses are being constructed only in accordance with the general rating, which is the lowest rating in the life-long housing certification system. The reason for this is that, since the infill system was created, it has not yet been actively used due to a rise in construction costs when infill products are utilized. In this regard, this study seeks to propose ways to optimize infill usage and create scenarios that can minimize the costs of life-long housing construction, taking into consideration variations in construction costs based on the characteristics of infill systems applied to housing.

• Journal of electromagnetic engineering and science
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• v.10 no.3
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• pp.104-116
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• 2010

With several advantages such as flexible downlink-to-uplink(DL-to-UL) ratio and flexible spectrum usage, Time Division Duplexing(TDD) is emerging as an alternate to Frequency Division Duplexing(FDD), especially in wireless broadband systems. We already have at least four different TDD systems in the industry: Time Division-Synchronous Code Division Multiple Access(TD-SCDMA), IEEE 802.16e-TDD, IEEE 802.16m-TDD, and Time Division-Long Term Evolution(TD-LTE). A disadvantage of TDD is that tight coordination such as time synchronization between adjacent operators is required to prevent interference between the adjacent TDD systems. In this paper, we investigate coexistence scenarios among the above four well-known TDD systems and calculate spectral efficiency(SE) loss in each scenario. Our findings are that SE loss can be significant if TDD ratios of the adjacent operators are considerably different. However, as long as the TDD ratios of the adjacent operators are similar, configurations in the systems permit perfect time synchronization between the two heterogeneous TDD systems, and the resulting SE loss is zero or reasonably low. We believe that the above findings and the configurations of the TDD systems recommended tominimize SE loss will be helpful for operators who deploy TDD systems in system parameter determination and cross-operator coordination.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.4
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• pp.435-445
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• 2012

In this paper, a design process is established by integrating aviation safety requirements for the development of general aviation aircraft. An Airworthiness-Design Integration System, which integrates certification requirements with the entire design/analysis process, is developed and presented. For the proposed system, KAS 23/FAR 23/AC 23/CS 23 certification regulations are analyzed to determine design constraints and system compliance checks and to construct an ER&G (Engineering Requirement and Guide) and a Design-Certification Related Table (DCRT). Furthermore, through building a DB (Data Base), the management of design and certification related resources for developing a FAR 23 class aircraft are made. Certification tools and resources are also efficiently managed by the DB. The connection between the certification requirements and the detailed design process is proposed in this system. Tracking of this proposed method is validated by configuring a USE CASE and a system. The Airworthiness-Design Integration system will be constructed based on the system's design plan, certification system, and usage scenarios.