• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1159-1166
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• 2014

In this paper, a resource management scheme for enhancing the network connectivity and reliability in wireless USB system is proposed. Wireless USB protocol is suitable for the application that supports the real-time multimedia service in Ship Area Network since it supports high speed data transfer. However, the device's mobility is caused the dramatic change of link state and network topology, and is occurred the degradation of network performance. Therefore, a resource management scheme for wireless USB system is proposed in this paper. The proposed technique can intelligently treat the change of link state, and solve the degradation of network performance. The simulation results show that proposed protocol can enhance the throughput and delay performance by selecting relay device with better link state.

• The Journal of Korean Association of Computer Education
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• v.17 no.5
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• pp.35-42
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• 2014

This study utilized an analysis of teachers' use of smart devices in the class, which highlighted the impact factors, and elucidated the relationship between in fluencing factors. The Unified theory of Acceptance and Use of Technology (UTAUT) model is based on the study of extension and modification of the model proposed. For the study, a survey of 1,016 elementary school teachers in the Gangwon and Metropolitan(Seoul, Gyeonggi, Incheon) area was conducted. Was applied using the AMOS structural equation modeling analysis. The analysis examines the utilization of smart devices in class as factors affecting performance expectancy, effort expectancy of the main variables showed, Instant connectivity and Openness that has a direct impact on the performance expectations and effort expectancy.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.2B
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• pp.133-142
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• 2007

WPANs are formed in relatively small area and a PNC that serves as a central control device plays an important role in the operation and organization of a piconet. Typical applications of WPANs are security system and health monitoring system. In these type of systems, guaranteeing realtime service is very important, and communications cannot take place when the PNC malfunctions. Thus, in this situation, it is necessary to elect a new PNC as soon as possible. For this reason, we propose distributed PNC election scheme that considers not only QoS support but also network connectivity to avoid possible network partition. Simulation results show proposed mechanism can select PNC with guaranteeing QoS and connectivity for a limited period.

• Journal of KIISE:Software and Applications
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• v.41 no.8
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• pp.545-556
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• 2014

Internet of Things (IoT), one of the emerging research areas, is the computing paradigm where various things connect to the network and cooperate with their neighbors to reach common goals. Computing with IoT devices opens up a new array of opportunities for providing value-added smart services and applications to end users. That is, IoT devices play an important role of providing useful services to the users. However, the states of IoT devices are dynamically changed at runtime, which come from their mobility, network connectivity, and a battery drain problem. This dynamism results in difficulties in managing these IoT devices. In this paper, we propose a framework to manage those IoT devices with dynamism. Hence, we first derive issues from IoT devices' dynamism. And, we define a set of requirements to manage the IoT devices and present a framework to manage the device dynamism. The framework is equipped by a device discovery method, a device status monitoring method, a device selection and connection method, and a device replacement method. Finally, we verify the feasibility and effectiveness of the framework through experiments.

• KIISE Transactions on Computing Practices
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• v.20 no.10
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• pp.561-566
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• 2014

There are growing demands for improving the patient safety and the effectiveness of medical services through device connectivity and interoperability. However, integration through networking might greatly increase the complexity of the system if it is not properly designed, jeopardizing patient safety. In this paper, we codify safe medical device interaction patterns, and exploit them for the low complexity design and safety analysis of networked supervisory medical systems. We implement the proposed approach as a plug-in of Architecture Analysis and Description Language (AADL). Our implementation enables the modeling and safety analysis of medical devices and their interactions before actual development.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.578-580
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• 2013

Recently, personal mobile devices increased according to the rise of smart devices. Thus the all smart devices load with a bluetooth of standard specifications. However, it is deficiency to service using multiple connection of bluetooth device connection limit. Also bluetooth have other problem. bluetooth can't data communication until all device connection. In this paper, we proposed multi-connect algorithm based on TDM using AT command to overcome the problems above. As a result, it is confirmed that the real-time connectivity and data transmission between multiple devices is possible.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.161-163
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• 2022

In spite of the recent enforcement of policies to reduce traffic accidents, pedestrian safety accidents on the back road continue to occur. In this paper, we propose a device design to prevent traffic accidents capable of measuring distance and wireless communication to quickly notify pedestrians of the vehicle's approach in a safety blind spot. The accuracy of vehicle and pedestrian distance measurement was tested using ultrasonic and radar sensors with a wide sensing range, and the possibility of responding to accidents that could provide safety for pedestrians in emergency situations was verified through a wireless communication connectivity test between target boards.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.10
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• pp.4662-4677
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• 2018

The dynamic opportunistic device-to-device (DO-D2D) network will frequently emerge in the fifth generation (5G) wireless communication due to high-density and fast-moving mobile devices. In order to improve the Quality of Experience (QoE) of users with different computing capacity devices in the DO-D2D network, in this paper, we focus on the study of how to reduce the packets retransmission delay and satisfy heterogeneous devices. To select as many devices as possible to transmit simultaneously without interference, the concurrent transmitters-selecting algorithm is firstly put forward. It jointly considers the number of packets successfully received by each device and the device's connectivity. Then, to satisfy different devices' demands while primarily ensuring the base-layer packets successfully received by all the devices, the layer-cooperation instantly decodable network coding is presented, which is used to select transmission packets combination for each transmitter. Simulation results illustrate that there is an appreciable retransmission delay gain especially in the poor channel quality network compared to the traditional base-station (BS) retransmission algorithm. In addition, our proposed algorithms perform well to satisfy the different demands of users with heterogeneous devices.

• Journal of Distribution Science
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• v.10 no.11
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• pp.89-99
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• 2012

Purpose - Mobile devices, especially mobile terminals capable of telecommunication and wireless connectivity, are leading the advancements in consumer electronics. Digital convergence drives the functions of various devices, such as cellular phones, MP3 players, personal digital assistants, and gaming, into a single device. This trend would continue and applications such as digital audio and video streaming (including personalized content delivery mechanisms) would soon be on a handheld device. As customers want mobile convergence devices, manufacturers are driving new initiatives in the emerging mobile device market. Given the roles played by device design and service content in user satisfaction of a mobile convergence device, this study focuses on identifying and measuring the constructs for the process by which user satisfaction is achieved. This study synthesizes the expectation-disconfirmation paradigm with empirical theories in user satisfaction. Device and service levels are separated, and nine key constructs for user satisfaction of mobile convergence devices are proposed. Insight into this process could help web-based businesses to improve user satisfaction, thus enhancing the effectiveness of e-commerce for sellers and buyers. Research design, data, methodology - This study draws on three users of mobile convergence devices as examples. To test there search model and hypotheses, survey questionnaires were sent to 607 mobile device users. Mobile device users were initially identified from several members, and subjects were randomly drawn. Data from 577 survey responses were finally analyzed. The unit of measurement and analysis in this research study is at a personal level. Results - The measurements for the constructs were developed and tested in a two-phase study. In the first phase, the device and service dimensions were identified, and instruments for measuring them were developed and tested. In the second phase, using the salient dimensions of the device and service as the formulating first-order factors, instruments were developed and empirically tested to measure satisfaction of the device and service. In measuring satisfaction of mobile convergence devices, the critical tasks are to identify the key constructs of such user satisfaction and to develop validated instruments to measure them. Hence, the results of this study have immediate implications for businesses and for research in user satisfaction of mobile convergence devices. Conclusions - This study provides reliable instruments for operationalizing key constructs in the analysis of user satisfaction of mobile convergence devices within the expectation-disconfirmation paradigm. Hence, convergence device makers will be able to examine whether their websites meet their customers' expectations by examining the device aspect of the mobile convergence device customers, and the service aspect expectations and disconfirmation. Moreover, the introduction of expectation and disconfirmation constructs brings the marketing aspect of convergence devices into focus for such retailers, an aspect crucial to the effective design of websites for online businesses. In addition,this study provides the metrics required to initiate future studies on user satisfaction of mobile convergence devices.

• Convergence Security Journal
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• v.8 no.3
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• pp.41-49
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• 2008

Other server based-application and the need of more complex interaction is required with functional strengthening and variational uses of mobile device. And mobile environments make a problem of continuous of web-service by making a problem of instance cutting between web-server and mobile device which acts as a client because of mobility. Therefore, this paper embodies a framework which keeps security and connectivity between HTTP based web-service and mobile device, and is for connection to web-service of mobile device which uses WAP in a standard protocol based mobile environment of mobile web-service for continuous web-service. This paper is analyzed in the same standard condition to compared functional delay which is based on HTTP and WAP access, and data transmission volume. Also it investigates improvement of execution overhead which is brought by interaction process.