• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.7-15
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• 2010

Recently, there are many home network applications using the convergence between mobile platforms and home network system. As smart phones which are called small PC in the hand becoming popular, the development of home network application beyond the one of cellular phones is required. Android mobile platform of Google includes OS, middleware and primary applications. Also, in addition to smart phones, it can be mounted on various devices such as set-top box and household appliances. In this paper, home network services on smart phones of Android platform are designed and implemented. The services provide real-time monitoring information (temperature, humidity, real-time video) of rooms and appliance control in a house.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1372-1377
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• 2013

In this Paper, a back propagation neural network learning algorithm based on the complex multilayer perceptron is represented for controling and detecting interference of the received signals in cellular mobile communication system. We proposed neural network adaptive correlator which has fast convergence rate and good performance with combining back propagation neural network and the receiver of cellular. We analyzed and proved that NNAC has lower bit error probability than that of traditional RAKE receiver through results of computer simulation in the presence of the tone and narrow-band interference and the co-channel interference.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10B
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• pp.845-853
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• 2003

It is expected that wireless LANs will substitute wired LANs and will be tightly coupled with mobile cellular systems. In this integrated network environment, vertical handoff between wireless LANs and mobile cellular systems is needed. In this paper, we propose handoff procedures and requirements for implementing of the vertical handoff. The proposed vertical handoff procedures are likely to be use as a basic example lot implementing of the vertical handoff.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.12C
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• pp.1245-1250
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• 2002

For recent years, the environment of use on internet has been changed from the wired internet access to the wireless internet access increasingly, and the use of real time application data has been increased. Therefore the research and evolution of wireless network for providing of user's mobility and QoS at the same time must be essential. IETF already proposed Mobile IPv6 for providing mobility and RSVP for QoS through resource reservation. These future are expected to be used not only wired network but also wireless network. But there are not yet proposed the integration and efficient interworking of two mechanism. For the solution of problem on efficient interworking issue, for instance signaling overhead and reservation delay increasing due to often handoff, this paper first proposed to use of IETF Cellular IP based on Mobile IPv6 for wireless network model with fast mobility and a improved RSVP mechanism using the flow label field in IPv6 header.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.581-584
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• 2004

Currently, there are many subscriber access networks: PSTN, ADSL, Cellular Network, IMT200 and so on. To these service providers that provide above network service, it is important that they authenticate and authorize legal subscribers and account for their usage. At present, There exist the several protocols that Support AAA(Authentication, Authorization and Accounting) service : RADIUS, Diameter, TACACS+. Nowadays, RADIUS has used for AAA service widely. It has been extended to support other access network environment. So, we extend RADIUS to support environment of Mobile IPv6. Mobile IPv6 uses IPsec as a security mechanism, basically. But, IPsec is a heavy security technology for small, portable, mobile device. Especially, it is serious at IKE, the subset of IPsec. IKE is a key distribution protocol that distributes the key to the endpoints of IPsec. In t:lis paper, we extend RADIUS to support environment of Mobile IPv6 and simplify the IKE phase of IPsec by AAA system distributing the keys by using its security communication channel. Namely, we propose the key distribution method for IPsec SA establishment between mobile node and home agent. The suggested method was anticipated to be effective at low-power, low computing deyice. Finally, end users feel the faster authentication.

• Proceedings of the CALSEC Conference
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• 2005.11a
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• pp.78-84
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• 2005

As the research activities related to 'Ubiquitous Computing' whose concept was introduced by Mark Weiser are growing, RFID(Radio Frequency Identification) technology has recently gained attention as a technology to advance the ubiquitous computing and a lot of related researches are also in progress. Research works done so far are mainly linked to the situation that the research outputs apply to meet the requirements for asset tracking and data sharing with partners over supply chain by using fixed RFID readers. However, it is essential that users have access to real-time information about the tagged objects and services whenever and wherever they want in the era of ubiquitous computing, so mobile devices-including PDA, smart phone, cellular phone, etc - which are equipped with an RFID reader can be regarded as an essential terminal for users living in ubiquitous computing environment. As far as the application with mobile devices are concerned, there are many considerations due to their limited capabilities of data processing, battery consumption and so on. In this paper, we review the generic RFID network model and introduce the revised RFID network model in consideration of incorporation with mobile devices equipped with an RFID reader. Also, we derive the requirements for software embedded within an RFID- enabled mobile terminal and then discuss essential components for implementation. Moreover, we develop the applications for asset management at museum by using mobile RFID network model.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.5
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• pp.833-841
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• 2011

In this paper, we propose uncoordinated dynamic frequency(channel) allocation schemes based on cognitive radio in mobile cellular networks(MCNs). Under the assumptions that mobile base stations are equipped with cognitive radio(CR) function and they construct uncoordinated network, the proposed scheme enables the MCNs by suppression of successive channel switching and management of channel allocation in a dynamic and distributed manner. The proposed scheme is composed of two phase processes. In the first phase, highly orthogonal sequences are generated and assigned to mobile base stations. In the second phase, each mobile base station is allocated a channel according to the pre-assigned orthogonal sequences. Simulation results show that the number of successive spectrum switching is reduced significantly compared with the random switching scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.12B
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• pp.1199-1210
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• 2010

In recent years opportunistic computing has gained popularity in Ad-hoc network research area and it is highly required to research for actual services and related requirements. In this paper we summarized a virtual opportunistic service that is named "Children Care System" and proposed an Ad-hoc communication node (uMobile) that is connected with cellular phone and a sensor node (uClo) which is embedding into clothes. uMobile can support cellular phone communication and Ad-hoc communication and uClo can be embedded into clothes and recognize the user status using multiple sensors. In this paper we implemented the location awareness and user status awareness services using uMobile and uClo. We also tested them in indoor situation and showed the result. We expect that our research can play a significant role to inspire another various opportunistic computing services.

• The Journal of the Korea institute of electronic communication sciences
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• v.1 no.2
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• pp.120-126
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• 2006

In this paper, we propose for improving QoS in hospital wireless network using Cellular-IP/PRC(Paging Route Cache) with Paging Cache and Route Cache in Cellular-IP. Although the Cellular-IP/PRC technology is devised for mobile internet communication, it has its vulnerability in frequent handoff environment. This handoff state machine using differentiated handoff improves quality of services in Cellular-IP/PRC. Suggested algorithm shows better performance than existing technology in wireless mobile internet communication environment. When speech quality is secured considering increment of interference to receive in case of suppose that proposed acceptance method grooves base radio station capacity of transfer node is plenty, and most of contiguity cell transfer node was accepted at groove base radio station with a blow, groove base radio station new trench lake acceptance method based on transmission of a message electric power estimate of transfer node be. Do it so that may apply composing PC(Paging Cache) and RC(Routing Cache) that was used to manage paging and router in radio Internet network in integral management and all nodes as one PRC(Paging Router Cache), and add hand off state machine in transfer node so that can manage hand off of transfer node and Roaming state efficiently, and studies so that achieve connection function at node. Analyze benevolent person who influence on telephone traffic in system environment and forecasts each link currency rank and imbalance degree, forecast most close and important lake interception probability and lake falling off probability, GoS(Grade of Service), efficiency of cell capacity in QoS because applies algorithm proposing based on algorithm use gun send-receive electric power that judge by looking downward link whether currency book was limited and accepts or intercept lake and handles and displays QoS performance improvement.

• Journal of Biomedical Engineering Research
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• v.30 no.3
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• pp.185-190
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• 2009

Biomedical mobile devices for ubiquitous healthcare consist of biomedical sensors and communication terminal. They have two types of configuration. One is the sensor-network type device using wired or wireless communication with intelligent sensors to acquire biomedical data. The other is the sensor embedded type device, where the data can be acquired directly by itself. There are many examples of sensor network type, such as, fall detection sensor, blood glucose sensor, and ECG sensors networked with commercial PDA phone and commercial phone terminal for ubiquitous healthcare. On the other hand, sensor embedded type mounts blood glucose sensor, accelerometer, and etc. on commercial phone. However, to enable true ubiquitous healthcare, motion sensing is essential, because users go around anywhere and their signals should be measured and monitored, when they are affected by the motion. Therefore, in this paper, two biomedical mobile devices with motion monitoring function were addressed. One is sensor-network type with motion monitoring function, which uses Zigbee communication to measure the ECG, PPG and acceleration. The other is sensor-embedded type with motion monitoring function, which also can measure the data and uses the built-in cellular phone network modem for remote connection. These devices are expected to be useful for ubiquitous healthcare in coming aged society in Korea.