• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1222-1232
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• 2011

RFID/USN core technologies for ubiquitous computing, It is possible to use variety of sensors, direct processors, and wireless network technology that easily collect the actual physical environment and can monitor information remotely. Especially the healthcare industry and services combined with U-Healthcare that have international competitiveness in the medical field. But the USN, standard management system of RFID such as EPCglobal architecture framework, the lack of interoperability issues and the global sensor network implementation. In this paper, a system for managing sensor nodes of the USN, USN of SIP-based management system (UMS) is proposed. UMS support Session Initiation Protocol (SIP), provide session management and mobility capabilities, that is based on Internet standard protocol. UMS architecture of the existing SIP architecture, added USN User Agent (UUA) and the USN Name Server (UNS) that the location of sensor nodes should be possible to trace. UUA on behalf of the limited capacity of the location of the sensor nodes to perform the registration process, UNS to track the location of the sensor nodes to provide name resolution services. The proposed management system has the advantage of internet applications such as Web services interoperability and easy to recycle existing resources with other SIP-based because it uses the Internet standard protocol SIP. In this paper we propose is based on the UMS blood temperature management system is verified through the scenario.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1A
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• pp.33-43
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• 2010

Recently, users want to use real-time multimedia services, such as internet, VoIP, etc., using their IEEE 802.11 wireless lan mobile stations. In order to provide such services, a handoff among access points is essential to support the mobility of a node, in such an wide area. However, the legacy handoff methods of IEEE 802.11 technology are easy to lose connections. Also, the recognition of a disconnection and channel re-searching time make the major delay of the next AP to connect. In addition, because IEEE 802.11 decides the selection of an AP depending only on received signal strength, regardless of a node direction, position, etc., it cannot guarantee a stable bandwidth for communication. Therefore, in order to provide a real-time multimedia service, a node must reduce the disconnection time and needs an appropriate algorithm to support a sufficient communication bandwidth. In this paper, we suggest an algorithm which predicts a handoff point of a moving node by using GPS location information, and guarantees a high transmission bandwidth according to the signal strength and the distance. We implemented the suggested algorithm, and confirmed the superiority of our algorithm by reducing around 3.7ms of the layer-2 disconnection time, and guaranteed 24.8% of the communication bandwidth.

• Journal of Broadcast Engineering
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• v.13 no.1
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• pp.6-16
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• 2008

An instable wireless channel condition causes more packet losses and retransmissions due to interference, fading, station mobility, and so on. Therefore video streaming service over a wireless networks is a challenging task because of the changes in the wireless channel conditions and time-constraints characteristics of the video streaming services. To provide efficient video streaming over a wireless networks, QoS-enhanced MAC protocol, IEEE 802.11e, is standardized recently. Tn this paper, we propose a new network-adaptive H.264 video streaming mechanism in the IEEE 802.11e wireless networks. To improve the quality of video streaming services, video stream has to adapt to the changes in the wireless channel conditions. The wireless channel conditions are estimated by the packet loss probability and informed to the application layer by the cross-layering. According to the wireless channel information, the video streaming application filters out the low-priority data. This adaptation mechanism efficiently uses system resources because it drops the low-priority data in advance. Therefore, our cross-layer design can provide improved video streaming services to the end-user. Through the implementation and performance evaluation, we prove that the proposed mechanism improves the QoS of the video streaming by providing the smoothed playback.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.38-48
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• 2006

For extending of hot-spot of WLAN, (2) proposes internetworking scheme between wireless LAN (WLAN) and mobile ad-hoc network (MANET), which employ the same layer-2 protocol with different mode. Compared to internetworking schemes between UMTS (Universal Mobile Telecommunications Systems) and WLAN (3-4), the scheme from (2) has relatively low overhead and latencies because WLAN and MANET are physically and logically similar to each other. However, the mode switching algorithm proposed in r2] for internetworking between WLAN and MANET only considers signal strength and determines handoff, and mobile nodes following a zigzag course in pollution area may perform handoff at short intervals. Furthermore, (2) employs mobile IPv6 (MIPv6) at base, which brings still high delay on handoff and overhead due to signal message exchange. In this paper, we present optimized internetworking scheme between WLAN and MANET, modified from (2). To settle ping-pong handoff from (2), we propose adaptive mode switching algorithm. HMIPv6 is employed for IP connectivity and mobility service in WLAN, which solves some shortcomings, such as high handoff overhead and vulnerable security. For routing in MANET, OLSR is employed, which is a proactive Protocol and has optimally reduced signal broadcasting overhead. OLSR operates with current P protocol compatibly with no change or modification. The proposed internetworking scheme based on adaptive mode switching algorithm shows better performance than scheme from (2).

• Journal of vocational education research
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• v.35 no.4
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• pp.47-61
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• 2016

The purpose of this study is to analyze student and university features affecting outcome in labor market after university graduates. For accomplish this, multi-level analysis modeling with HLM(Hierarchical Linear Modeling) was adopted. GOMS(Graduates Occupational Mobility Survey) 2013 data were used for this study, and we added the Information Service of Education data for university information. The result of analysis were as follows. (a) Factors affecting outcome in labor market after university graduate were both student and university features. Significant features were house income, gender, academic major, GPA, and satisfaction in view point of student level. In university level, there were significant variables likes foundation, location, education costs, school type, and satisfaction. (b) We found the different significant variables between student and school level in the participations on the university career program. Significant features were job-experience and job-exhibition in student level, but there were no significant after adding variable in school level. In the school level, there were significant in subjects related career and job, job-exhibition, and consulting.

• Journal of Korea Entertainment Industry Association
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• v.15 no.3
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• pp.13-26
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• 2021

The purpose of this study is to understand the relationship between the subfactors(economic benefits, customized benefits, psychological benefits) of tourism SNS benefits and the intention to reuse tourism SNS values, and propose measures to revitalize the tourism industry through marketing strategies that can continuously provide differentiated services from customers through long-term relationship formation, increase profits, maintain and secure customers. This study conducted an empirical analysis of 326 people aged 19 or older. The results of the study are as follows. First, in the relationship between tourism SNS benefits(Economic benefits, customized benefits, psychological benefits) and tourism SNS values(economic value, functional value, emotional value), it was confirmed that tourism SNS benefits have a positive impact on all of the tourism SNS values. Second, in the relationship between the sub-factors of tourism SNS values and the intention of reuse, it was analyzed that all sub-factors of SNS values have a positive effect on the intention of reuse. Based on result of this study, developing contents such as mobility apps to strengthen long-term relationships with customers to maximize the value of tourism SNS and tourism SNS will improve the reuse of tourism service.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.2
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• pp.119-133
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• 2022

Due to the improvement of surveying, mapping and communication techniques, various apps for road direction guides and vehicle navigations have been developed. Although such a development has impacted on walking and driving, there is a limit to improving the daily convenience of the socially impaired people. This is mainly due to the fact that the software have been developed for normal pedestrians and drivers. Therefore, visually impaired people still have problems with the confusion of direction and/or non-provision of risk factors in walking. This study aimed to propose a scheme which constructs data for mobility-impaired or traffic-impaired people based on various geospatial information. The factors and components related to walking for the visually impaired are selected by geospatial data and a walking route guidance network that can be applied to a commercial software. As a result, it was confirmed that road direction guidance would be possible if additional contents, such as braille blocks (dotted/linear), sound signals, bus stops, and bollards are secured. In addition, an initial version of the application software was implemented based on the suggested data model and its usefulness was evaluated to a visually impaired person. To advance the stability of the service in walking for the visually impaired people, various geospatial data obtained by multiple institutes are necessary to be combined, and various sensors and voice technologies are required to be connected and utilized through ICT (Information and Communications Technologies) technology in near future.

• Journal of Navigation and Port Research
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• v.46 no.6
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• pp.570-575
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• 2022

The MX-S2X, utilizing high-frequency broadband communication technology, provides a reliable connection between land, ship, and facilities. This technology is expected to be effectively utilized as a future maritime communication infrastructure in the upcoming mixed navigational situation among autonomous and manned and/or unmanned ships. Following the physical layer design and M&S-based performance analysis of the MX-S2X system to overcome maritime multipath fading, this paper confirms the optimized and detailed design of physical layer hardware and implemented it to verify the performance. The PER(Packet Error Rate) performance was then measured by configuring a test environment to verify the implemented hardware. The results showed that the performance degradation was 0.2 dB in the AWGN environment and 1.2 dB in the Multi-path Fading on Sea Environment, thus confirming the successful implementation of the physical layer.

• The Journal of the Korea Contents Association
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• v.22 no.2
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• pp.173-186
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• 2022

The purpose of this study is to investigate the influence of gamification strategies on improving participation and motivation of shared electric scooter users. To this end, this study derived the user type through the first research question of how the shared electric scooter usage behavior and pulse are, and derived user tasks and scenarios. The second research question, a shared electric kickboard app with gamification, was tested by users to see if it helps increase user participation and form motivation. As a result of the analysis, it was found that users were induced to be considerate of other users by using a combination of the motivational, relational, and self-expression strategies of gamification. Second, it was found that the use of motivation, achievement and reward, and reward visualization strategy elements promotes user's voluntary behavior. Third, through relationship, achievement, and reward strategies, users participated to create a positive culture of shared electric scooters, drawing immediate feedback, indicating that convenience has increased. In conclusion, it was found that the user helped to play a positive role in voluntary participation and motivation through the use of the shared electric kickboard service with gamification.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.1
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• pp.233-251
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• 2023

Metropolitan buses are managed as either a direct seat type or a metropolitan express type according to the 「Passenger Transport Service Act」. However, a management system that reflects the characteristics of metropolitan buses is not currently established. Therefore, in this study, the driving characteristics of metropolitan buses, dangerous driving behavior characteristics of metropolitan bus drivers, metropolitan bus accident characteristics, and the safety management system of domestic and foreign buses and other means were investigated. Through this, a plan for strengthening the safety management of metropolitan buses suitable for Korea was presented by dividing it into short-term and mid to long term. The short-term plan is a plan that can be carried out through consultation between metropolitan bus agencies and transportation companies, and the mid to long term plan is a plan that can be implemented only when related laws are revised. Through this study, it is expected to serve as an opportunity for in-depth discussions by the government, business operators, and related experts to strengthen the safety management of metropolitan buses.