• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.569-572
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• 2005

A generation to have felt convenience of a network by a development of Internet is pressing for realization of a wireless network. However, security of wireless network must begin with an attack to be good at all expectations. especially considred from L1 layer to L7 layer. Wireless Network weaker than wire because smuggle through various sensor terminal and invasion of radio waves netwwork Wireless network recognizes a security proposal of physical, network application layer, and is going to discuss a security development point of wiress network from now on.

• The KIPS Transactions:PartC
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• v.9C no.1
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• pp.39-44
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• 2002

In this paper, in order to improve the performance of TCP short traffic application services in wireless Internet environments, the Split-ACKs (SPACK) scheme is proposed. In wireless networks, unlike wired networks, packet losses will occur more often due to high bit error rates. Therefore, each packet loss over wireless lints results in congestion control procedure of TCP being invoked at the source. This causes severe end-to-end Performance degradation of TCP. In this paper, to alleviate the TCP Performance, the SPACK method, split acknowledgement Packets in the base station, is proposed. Using computer simulation, the performance of TCP using SPACK is analysed and shows better performance than traditional TCP Protocol.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.9
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• pp.1528-1543
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• 2011

With increasing the using of wireless technologies in essential fields such as the medical application, this paper proposes different scenarios for the transmission of images over wireless networks. The paper uses the IEEE ZigBee 802.15.4 for applying the proposed schemes. It is a Wireless Personal Area Network (WPAN). This paper presents a novel chaotic interleaving scheme against error bursts. Also, the paper studies the proposed interleaver with the convolutional code with different constraint lengths (K). A comparison study between the standard scheme and proposed schemes for image transmission over a correlated fading channel is presented. The simulation results show the superiority of the proposed chaotic interleaving scheme over the traditional schemes. Also, the chaotic interleaver packet-by-packet basis gives a high quality image with (K=3) and reduces the need for the complex encoder with K=7.

• Journal of Biomedical Engineering Research
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• v.27 no.4
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• pp.197-202
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• 2006

Devices in current market to perform electrical stimulation therapy of the urinary incontinence frequent in aging women are very much impractical to us ε due to the wired configuration. The present study implemented new wireless device to enhance self as well as in-hospital therapy with the easiest and the most convenient application. The therapy system consisted of two modules, called 'master' and 'slave', communicating with each other by the wireless Bluetooth protocol. The patient controls therapy processes on the master module in hand, transmitting the required informations to operate the slave module placed within her pants with the viginal electrode connected, delivering appropriate electrical stimulation. Wireless communication enabled self therapy with clothes on, leading to a great convenience for the patient. The stimulation output signal was comparable to commercialized products in both waveform and stimulation capacity.

• Smart Structures and Systems
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• v.6 no.5_6
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• pp.661-673
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• 2010

This paper presents recent developments in an extremely compact, wireless impedance sensor node (the WID3, $\underline{W}$ireless $\underline{I}$mpedance $\underline{D}$evice) for use in high-frequency impedance-based structural health monitoring (SHM), sensor diagnostics and validation, and low-frequency (< ~1 kHz) vibration data acquisition. The WID3 is equipped with an impedance chip that can resolve measurements up to 100 kHz, a frequency range ideal for many SHM applications. An integrated set of multiplexers allows the end user to monitor seven piezoelectric sensors from a single sensor node. The WID3 combines on-board processing using a microcontroller, data storage using flash memory, wireless communications capabilities, and a series of internal and external triggering options into a single package to realize a truly comprehensive, self-contained wireless active-sensor node for SHM applications. Furthermore, we recently extended the capability of this device by implementing low-frequency analog-to-digital and digital-to-analog converters so that the same device can measure structural vibration data. The compact sensor node collects relatively low-frequency acceleration measurements to estimate natural frequencies and operational deflection shapes, as well as relatively high-frequency impedance measurements to detect structural damage. Experimental results with application to SHM, sensor diagnostics and low-frequency vibration data acquisition are presented.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.260-263
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• 2019

Recently, the need of researches and developments about WSN(Wireless Sensor Network) technologies, which can be applied to services to regions where the access is difficult or services that require continuous monitoring, has gradually increased due to its expansion and efficiency of the application areas. In this paper, we analyze existing researches which focused on reducing packet loss rate and increasing lifetime of sensor nodes. Then, we conduct studies about performance improvement factors where some schemes - clustering and location-based approaches - are applied and compare our study results with existing researches. Based on our studies, we are planning to conduct researches about a new scheme that could contribute to improve WSN's performance in terms of packet loss rate and network lifetime.

• Journal of electromagnetic engineering and science
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• v.3 no.1
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• pp.12-16
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• 2003

In this paper, low noise amplifiers with coplanar waveguide structure are presented for Wireless LAN data communication application. For comparison of microwave performance, LNAs of cascode type and balanced type using cascode cell with the same substrate and same bias conditions are designed and implemented. A cascode type of LNA shows the gain of 12.45 ㏈, input return loss of 11.63 ㏈, and noise figure of 1.52㏈. A balanced type of LNA using cascode cell shows the gain of 6.58 ㏈, input return loss of 16.6 ㏈, and noise figure of 1.18 ㏈.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.376-378
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• 2003

Internet의 확대와 망의 진화에 따라 현 통신 방식은 기존 회선 교환 방식에서 패킷 교환 방식으로 진화를 한다. NGN(Next Generation Network)이란 정확하게 정의를 내리기는 어렵지만, 개념적으로는 현존하는 모든 서비스(Voice, Data, Video 등)들과 미래에 나타날 멀티 서비스를 통합하여 수용할 수 있는 패킷 기반의 통신망을 의미한다. 이러한 개념은 망의 통합을 목적으로 하는 NGcN(Next Generation Convergence Network, 이하 NGcN)로 진화하고 있다. 하지만, 진정한 의미의 NGcN은 Legacy 회선 교환 방식(include Wireless Network)과 패킷 교환 방식의 모든 망 사용자에게 동일한 서비스를 제공하는 것이며, 이것은 Convergence Service라는 개념으로 정리를 할 수 있다. 본 논문에서는 이와 같은 접근을 Next Generation Convergence Service(이하 NGcS)로 정의를 한다. 논문에서는 NGcS 구축을 위해 지능망 서비스와 연계하여 접근을 할 것이며, INAP(Intelligent Network Application Protocol), WIN(Wireless Intelligent Network) 및 CAP(CAMEL Application Part) 등의 제어방식에 근거한다. 이러한 방식들에 대한 연동에 대해 논하며, NGcS 구축을 위한 Service Switching Function 설계 방법과 서비스를 트리거(Trigger)하기 위한 방법에 대해 논한다.

• 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.

• Electronics and Telecommunications Trends
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• v.35 no.5
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• pp.139-150
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• 2020

Fifth-generation (5G) wireless communication supports low latency of up to 1 ms or less, 20 Gbps of data rate, and more than 1 million connections. With these technical advantages, machines and equipment can be precisely adjusted, allowing 5G to be applied to industrial applications. To expand the industrial application of 5G wireless communications, major countries have introduced dedicated 5G, allowing specific companies to build and use 5G directly. Germany, UK, and Japan allocate 100 MHz, 416 MHz, and 1,200 MHz, respectively, of bandwidth dedicated to 5G. Companies with local licenses from the government are expected to accelerate the application of 5G at a low cost and low-frequency range. Therefore, Korea should introduce private 5G to foster 5G-related industrial ecosystems and successfully implement the fourth industrial revolution.