• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.453-456
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• 2007

In this paper, we describes a design of Wireless Mesh Network based middleware that applied into USN(Ubiquitous Sensor Networks). WMN based middleware is a technique which links data between widely distributed sensor devices and WMN for context-awareness. The use of WMN base middleware in this paper makes possible communication on insufficiently network constructed area by use of WMN. WMN based middleware also anaylze events comprehensively that originated from specific sensor device. Based on the result from analyzed data with predetermined value WMN based middleware will given an order to designated actuator devices. Middleware operate each function of sensor network management and application service separately.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.73-78
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• 2009

We researched economic efficiency and possibility of game portal service based PDA/Smart phone by popularize of next generation portable internet WiBro. PDA/Smart phone are difficult to equal level content service with PC, because of it has low CPU and memory than PC. This paper are implemented paper of integrated server of Cable or Wireless for WiBro contents. In this research, we implemented and show test result of CP killer contents in PDA. It can apply to WiBro portable internet and has required many functions in integrated server for cable or wireless. CP Killer contents for WiBro portable internet is developed by PC server base on Window XP. It can accept next generation wireless LAN, portable internet and ubiquitous issues. We expect activation of commercial use that WiBro contents and server trading.

• Journal of KIISE:Computing Practices and Letters
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• v.6 no.1
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• pp.103-112
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• 2000

As today's market share of Intelligent Network (IN) service and wireless tele-communication is growing rapidly, the increment in service requests of wireless IN service subscribers and users has to be taken into account for implementing advanced IN services. In this paper, we design Global Service Logic for IN Freephone service, which is one of the commercially most interesting IN services, applied call queuing service feature with mass call processing to enhance call completion rate by considering the mobility of wireless service subscribers with mobile terminals as well as existing wireline service subscribers. Due to the location management of each IN subscribers 'mobile terminals, we design the structure and operation mechanism of Queue Manager which adjusts dynamically service subscribers groups according to their mobility. We optimize the queue size according to the call attempt rate and drop rate, and present the appropriate waiting time in the queue.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.1
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• pp.24-28
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• 2010

This paper is presented on the antenna design for notepc platform. We present the antenna with combination of electric-magnetic radiator for dual-band Wireless Local Area Network (WLAN) service and a High Speed Downlink Packet Access (HSDPA) service. Due to the limited antenna space in notepc platform, the antennas for various wireless communication service should be located at a very small area. In this paper, the magnetic-type radiator works for high frequency band (1.7 - 2.1 GHz) application and the electric-type radiator works for low frequency band (820 - 960 MHz) application. This combination produces wide-band characteristics in the high frequency band. Simulation and experimental results of input impedance and gain characteristics of the proposed antenna are presented. There are good agreements between the simulated and measured S11 and gain values.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.2 no.3
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• pp.325-333
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• 1998

In this paper, conventional STM(Synchronous Transfer Mode) supports another traffics by using idle channels. Proposed mobile terminals are distributed independently at the BSA(Basic Service Area). So, MAC(Medium Access Control) specified on the wireless ATM networks, which is managing statistics multiplewing functions, idle channel's ultilization is maximized and multimedia service characteristic for conventional wired networks based fixed assignment scheme(connection-oriented) and random assignment scheme(connection-oriented) improving on dynamic reservation based MAC protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.123-140
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• 2011

In this paper, we propose an Energy Efficient Media Access Control (EE-MAC) protocol for wireless sensor networks. The proposed scheme is designed to save power consumption and guarantee quality-of-service for real-time traffic. EE-MAC uses the superframe structure which is bounded by the transmission of a beacon frame and can have an active and an inactive portion. The active period is divided into the contention free period (CFP) for real-time traffic transmission and the contention access period (CAP) for non-real-time traffic transmission. We propose the exclusively allocated backoff scheme which assigns a unique backoff time value to each real-time node based on bandwidth allocation and admission control. This scheme can avoid collision between real-time nodes by controlling distributed fashion and take effect a statistical time division multiple access. We also propose the algorithm to change the duty cycle adaptively according to channel utilization of media depending on network traffic load. This algorithm can prolong network lifetime by reducing the amount of energy wasted on idle listening.

• Journal of Korea Society of Digital Industry and Information Management
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• v.14 no.4
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• pp.219-228
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• 2018

The utilization of NFC has been continuously increasing due to the spread of smart phones and the development of short-range wireless communication networks. However, it has been suggested that stability and security of convenient NFC short-range wireless communications can be unstable and problematic. The unstable causes for NFC are the lack of security technologies for NFC, the controversy about personal information infringement, and the lack of social awareness on security breach against data settlement. NFC service can be conveniently used by simply touching other NFC devices and NFC tags through the NFC device. This thesis analyzes that NFC authentication technology, which is convenient for user are one of the unstable causes of security of NFC. This thesis suggest that ministry should research countermeasures and promote how users can use NFC safely. It also suggests that users should have awareness when they use payment and authentication service through NFC to prevent from security threat.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5669-5684
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• 2018

The new mobile edge network architecture has been required for an increasing amount of traffic, quality requirements, advanced driver assistance system for autonomous driving and new cloud computing demands on highway. This article proposes a hierarchical cloud computing architecture to enhance performance by using adaptive data load distribution for buses that play the role of edge computing server. A vehicular dynamic cloud is based on wireless architecture including Wireless Local Area Network and Long Term Evolution Advanced communication is used for data transmission between moving buses and cars. The main advantages of the proposed architecture include both a reduction of data loading for top layer cloud server and effective data distribution on traffic jam highway where moving vehicles require video on demand (VOD) services from server. Through the description of real environment based on NS-2 network simulation, we conducted experiments to validate the proposed new architecture. Moreover, we show the feasibility and effectiveness for the connected car media service on highway.

• Proceedings of the KIEE Conference
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• 2007.10a
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• pp.397-398
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• 2007

Currently, most of Passenger Service System is supported to VOD in Korea. This current PSS has not internet access, real time broadcasting system and entertainment. The system did not come up to the expectation of consumer. This paper presents an application of new Passenger Service System for developing multimedia as well as wireless communication technology on internet, satellite broadcasting.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.5
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• pp.791-796
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• 2013

Advent of the brain wave health care system is considered as an important issues in the industrial and research area in these days. It is necessary to detect EEG signals in real-time in order to support the medical emergency service for the epileptic or brain infarct patients. Since the efficient network support is an essential factor for the system, several topologies using sensor node based wireless body area network is suggested and simulated in this paper. Finally the Opnet simulation result is evaluated for the efficient topology of the body area network.