• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.144-148
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• 2005

In this paper, we have proposed VGA fur MB-OFDM UWB application using $CMOS\;0.18\;{\mu}m$ technique. The proposed VGA can vary power gain from 45 dB to -6 dB and 3 dB band width is more than 264 MHz. It has 3-stage cascade structure and DC offset cancellation. It consumes less, than 4 mA for 1.8 V bias voltage.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.7 no.8
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• pp.2061-2080
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• 2013

Roaming authentication protocol is widely used in wireless network which can enable a seamless service for the mobile users. However, the classical approach requires the home server's participation during the authentication between the mobile user and the foreign server. So the more the roaming requests are performed the heavier burden will be on the home server. In this paper, we propose a new roaming authentication framework for wireless communication without the home server's participation. The new roaming authentication protocol in the new framework takes advantage of the ID-based cryptography and provides user anonymity. It has good performance compared with the roaming authentication protocols whose authentication do not need the home server's participation in terms of security and computation costs. Moreover, a new User-to-User authentication protocol in the new framework is also present. All the authentications proposed in this paper can be regarded as a common construction and can be applied to various kinds of wireless networks such as Cellular Networks, Wireless Mesh Networks and Vehicle Networks.

• Journal of Digital Convergence
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• v.15 no.4
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• pp.259-266
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• 2017

The massive traffic interferences in the wireless home IoT provides the reason for packet losses, and it degrades the QoS (Quality of Service) and throughput on the home network. This paper propose a new adaptive traffic interference control system, ATICS, for enhancing QoS and throughput for IoT services as detecting a traffic process and non-traffic process in the wireless home network. The proposed system control the traffic interferences as distinguishing the short-term traffic process and long-term traffic process by traffic characteristics in wireless home networks. The simulation results shows that the proposed scheme have more efficient traffic control performance than the other schemes.

• Journal of Digital Contents Society
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• v.7 no.2
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• pp.103-108
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• 2006

Short-range wireless communication and networking technologies are becoming increasingly important in enabling useful mobile applications. for example, ZigBee technology is expected to provide low cost and low power connectivity for equipment that needs battery life as long as several months to several years. In addition, ZigBee can be implemented in mesh networks larger than is possible with Bluetooth. The main features of this ZigBee standard are network flexibility, low cost, very low power consumption, and low data rate in an adhoc self-organizing network among fixed, portable and moving devices. Home network/Home automation is one of the key market areas for Zigbee, with an example of a simple network This paper investigates the effect of short range wireless channel on the performance of Zigbee system and DSSS-BPSK signal transmission in AWGN, interference and Rician fading environments. And we investigate performance degradation due to interference and fading effects in short range wireless channel. In particular, the impacts of the fading and interference level on the bit error probability is shown in BER performance figures.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.189-193
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• 2005

In this paper, we propose a direct conversion double-balanced down-converter fer MB-OFDM W system, which is implemented using $0.18\;{\mu}m$ CMOS technology and its measurement results are shown. The proposed down-converter adopts a resistive current-source instead of general transconductance stage using MOS transistor to achieve wideband characteristics over RF input frequency band $3\~5\;GHz$ with good gain flatness. The measured conversion gain is more than +3 dB, and gain flatness is less than 3 dB for three UWB channels. The dc consumption of this work is only 0.89 mA from 1.8 V power supply, leading to the low-power W application.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.206-208
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• 2004

A new method to control a remote robot with PDA and wireless network is presented. The needs of remote control systems using a home network environments are increased in these days. To solve the shortage of IP address in network, authorized TCP/IP and unauthorized TCP/IP address are used. The unauthorized TCP/IP is obtained by using MAC Address in the system and Network Layer. The model in the system is similar to Sever&Client in structure. Using this system, it is very easy to combine one network device with other network system. A robot system and PDA are used to show the effectiveness of the control system in home network environments.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.6
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• pp.695-700
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• 2005

In the sensor network, a lot of sensor nodes are scattered sparsely and organizes a united communication network between each node. After that, environmental information around each sensor node are gathered and analyzed. Because each node operates under resource constraint, the efficiency and hardware specification of a node should be maximized. There exist technical constraints until now but recent technical progress in IC fabrication and wireless network enables to construct a tiny embedded system, which has the properties of low cost, low power consumption, multi functions. Wireless sensor network becomes a modern research field with technical improvements, is studied in numerous laboratories, and is called as diverse different project names - Wireless Integrated Network Sensors (WINS), Mobile Ad hoc NETwork (MANET), Ubiquitous Sensor Network (USN). TinyOS is one of leading project and is widely used. In this paper, we suggest a sensor network, which uses TinyOS platforms and aims for context awareness in a home environment.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.4
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• pp.441-450
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• 2001

This dissertation deal with over-all wireless communication technology. And introduce wireless communication technology analytically that it use for Home-LAN communication technology (HomeRF, Bluetooth, IEEE 802.11, HIPERLAN, etc). Home-LAN communications issue by the terminal field of the latest high-speed network construction. This technologies possesses characteristics and significances as the representative technology using in Home-LAN communication technology. Also, the method of application is conditional on individually. Wireless LAN put Home-LAN communications to practical use. Bluetooth have practical use for an individual mobile communications with internet. HomeRF have a vision that the construction of wireless system in house purely. Therefore, this dissertation investigates merits and demerits between those technologies. And then leads the most compatible technology for application of Home-LAN. Finally, this thesis have a view of the development course hereafter.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1563-1567
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• 2005

The Home network system means that information appliances, Home PCs, etc., using wired or wireless network method enable to control and share with peripheral devices such as internet, shared data, a scanner and a printer, and it is networking solution, which intelligent communication will be possible as the system which can do a remote control such as TV Set, refrigerators, air conditioners, DVD players, digital camcorders based on external network using an internet, a potable information terminal and a mobile phone whenever, wherever and freely. In this study, the home network interface solution is used one of the wired network standards, PLC (Power-Line Communication) technology, so we can construct of intelligent home network's home controller without re-build a network at home. On keeping with current waves of thought, we will focus on a home controller development with great interest which is enabled to do an effective managed control, applying intelligent home network technology which can be new paradigm like a cyber apartment.

• Journal of the Korea Computer Industry Society
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• v.7 no.5
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• pp.487-494
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• 2006

By development of the superhigh speed network and the Networked appliance, a home network environment was equipped quickly around the cyber apartment. The home network environment provides the abundant family life style which numerous appliance and tools are connected with the network. Recently it is caused by with appearance of the Networked appliance which is connected with the network, the service demand is augmented to hacking, wrong operation, breakdown, crime prevention in home automation, fire, and break-in. This paper planned and proposed the integrated crisis management service model in the environment of home network and Networked appliance. Namely, it classifies the Networked appliance crisis management service and it defines a crisis management message with the XML. The message where the crisis situation occurs is notified and controlled in wireless PDA or the hand phone or the specific authorization.