• 한국태양에너지학회 논문집
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• 제28권6호
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• pp.58-63
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• 2008

It is essential to investigate the structure and the main characteristic of Home USN (Ubiquitous Sensor Network) technologies in built ubiquitous environment while designing bio-sensors. For this study, Thermistor elements and Thermopile black body have been selected to implement ubiquitous technologies for bio-sensors and wireless network such as WiBro has been used to transfer sensing data to the BSN (Bio-Sensor Network) gateway. It is certain that efficiency of ubiquitous space design is improved if main components of each specific sensor network are analyzed precisely in digital way and corresponding communication modules are prepared accordingly. Ubiquitous technology, in conclusion, has to be applied not only with systematical mechanism or electronic setting but in human-centered atmosphere as well, keeping with deep consideration for bio-housing service factors in eco-friendly surrounding.

• Journal of Communications and Networks
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• 제7권4호
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• pp.401-407
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• 2005

Simulations are currently an essential tool to develop and test wireless sensor networks (WSNs) protocols and to analyze future WSNs applications performance. Researchers often simulate their proposals rather than deploying high-cost test-beds or develop complex mathematical analysis. However, simulation results rely on physical layer assumptions, which are not usually accurate enough to capture the real behavior of a WSN. Such an issue can lead to mistaken or questionable results. Besides, most of the envisioned applications for WSNs consider the nodes to be at the ground level. However, there is a lack of radio propagation characterization and validation by measurements with nodes at ground level for actual sensor hardware. In this paper, we propose to use a low-computational cost, two slope, log-normal path­loss near ground outdoor channel model at 868 MHz in WSN simulations. The model is validated by extensive real hardware measurements obtained in different scenarios. In addition, accurate model parameters are provided. This model is compared with the well-known one slope path-loss model. We demonstrate that the two slope log-normal model provides more accurate WSN simulations at almost the same computational cost as the single slope one. It is also shown that the radio propagation characterization heavily depends on the adjusted model parameters for a target deployment scenario: The model parameters have a considerable impact on the average number of neighbors and on the network connectivity.

• 한국콘텐츠학회논문지
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• 제11권4호
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• pp.101-111
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• 2011

최근 유무선 통신 기술의 발전 및 모바일 정보기기의 보편화에 힘입어, 시간과 장소에 제약 없이 서비스를 제공할 수 있는 유비쿼터스 컴퓨팅(Ubiquitous computing)기술이 각광받고 있다. 이에 따라, 무선 센서네트워크(Wireless Sensor Network: WSN) 기술과 상황인식(Context-awareness) 기술에 대한 관심이 크게 고조 되고 있으며, WSN과 상황인식을 접목하여 다양한 분야에서 활용할 수 있는 응용시스템의 개발이 활발하다. 하지만 기존 상황인식 기술을 WSN에 적용할 경우, 첫째, 불필요한 데이터를 전송하여 에너지효율성을 저하시키는 단점이 존재한다. 둘째, 새로운 응용 서비스를 구현할 경우, 특정 응용에 의존적이 기 때문에, 새로운 상황인식 모듈을 구현해야 하는 문제점이 있다. 이를 위해 본 연구에서는 무선 센서 네트워크에서 상황인식에 근거한 새로운 실시간 감시시스템을 제안한다. 제안하는 시스템은 센서노드에서 상황인식을 수행하여 불필요한 데이터 전송을 줄여 에너지 효율성을 높이고, 모듈화를 통해 새로운 상황인식 기능을 지원할 수 있는 확장성을 지닌다.

• 정보보호학회논문지
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• 제25권2호
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• pp.467-478
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• 2015

사물인터넷에 대한 관심이 증가하면서 사물인터넷에 적합한 여러 보안 기술들이 연구되고 있다. 특히 디바이스 센서 네트워크 영역에서는 사물인터넷의 특성상 저사양 디바이스의 사용이 증가하고 다양화되었다. 그러나 현재의 인증 기술등의 보안 기술을 저전력 저사양 디바이스에 그대로 적용하기에 어려움이 있고, 이로 인해 보안 위협도 증가하였다. 따라서 사물인터넷의 센서 네트워크 통신상의 엔티티간 인증 프로토콜이 연구되고 있다. 2014년 Porambage 등은 타원곡선 암호 알고리즘에 기반한 센서 네트워크 인증 프로토콜을 제안하여 사물인터넷 환경의 안전성을 향상하고자 하였지만, 취약성이 존재하였다. 이에 따라 본 논문에서는 Porambage 등이 제안한 타원곡선 암호 알고리즘 기반 인증 프로토콜의 취약성을 분석하고, 사물인터넷 환경에서 센서 네트워크에 대한 개선된 인증 프로토콜을 제안한다.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2006년도 정기학술발표대회 논문집
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• pp.606-609
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• 2006

국내 건설업은 90년대 중반 이후 잇따른 건설구조물 붕괴사고가 발생하기 이전까지 구조물의 완공 자체에만 치중하여 유지관리분야에 대해서는 상당히 소홀했던 것이 사실이다. 현재, 국내의 시설물 모니터링체계는 유선방식의 대형시설물을 중심으로 극히 제한적으로 활용되고 있는바, 전국의 노후화된 수많은 중, 소형 시설물을 모니터링 하기에는 한계가 있다. 최근 센서, 센서네트워크, 무선통신 등 유비쿼터스 관련 기술의 급속한 발전으로 인하여 이를 건설분야에 적용하고자 하는 노력들이 증가하고 있는 추세이다. 그러나, 이와 같은 각종 연구가 진행되고는 있는 반면, 실제 실용화를 위한 연구나 기술개발은 미비하며, 특히 시설물 모니터링 분야에서의 적용 연구는 더욱 미흡한 실정이다. 따라서, 본 논문은 유비쿼터스 환경의 시설물 모니터링 시스템 구현을 위해 필요한 각 단계별 모듈 구성에 대한 방법론에 대하여 논하고자 한다.

• 디지털융복합연구
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• 제4권1호
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• pp.31-41
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• 2006

This article introduces developing trends of an 'Ubiquitous Interface' as an access method for use of various network resources, such as public wireless networks and un-licensed wireless networks in ubiquitous sensor network environments, without troublesome settings or operations by users. 'Ubiquitous Interface' is a relatively wide sense meaning not only physical interface of specified device or between processors, but anything method for access USN. These 'Ubiquitous Interface' able to provide seamless services that adapt autonomously to the user's movements and changes in the state of wireless resources. Recently, strongly recommended current technologies are RFID, NFC, Multi-mode mobile terminal, UMA mobile terminal and Wearable computer as a future ubiquitous interface. These technologies are have to have flexibility and multiple physical communication channels for seamless service hand over and serve easy connection at huge USN to user. Also, they have to must have flexible software structure. Finally, through the 'Ubiquitous Interface', we will be experience of seamless communication and realize a real liberty of communication.

• 전자통신동향분석
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• 제34권2호
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• pp.10-18
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• 2019

Since the introduction of CRT(Cathode Ray Tube) in the 1950s, display technologies have been developed continuously. Flat panel displays such as PDP(Plasma Display Panel) and LCD(Liquid Crystal Display) were commercialized in the late 1990s, and OLED(Organic Light Emitting Diodes) and Micro-LED(Micro-Light Emitting Diodes) are now being developed and are becoming widespread. In the future, we expect to develop ultra-realistic, flexible, embedded sensor displays. Ultra-realistic display can be applied to AR/VR(Augmented Reality/Virtual Reality) devices and spatial light modulators for holography. The sensor-embedded display can be applied to robots; electronic skin; and security devices, including iris recognition sensors, fingerprint recognition sensors, and tactile sensors. AR/VR technology must be developed to meet technical requirements such as viewing angle, resolution, and refresh rate. Holography requires optical modulation technology that can significantly improve resolution, viewing angle, and modulation method to enable wide-view and high-quality hologram stereoscopic images. For electronic skin, stable mass production technology, large-area arrays, and system integration technologies should be developed.

• Journal of Information Technology Applications and Management
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• 제12권4호
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• pp.93-104
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• 2005

Recently, RFID/USN is one of fundamental technologies in information and communications networks. Low-Rate WPAN, IEEE802.15.4 is a low-cost communication network that allows wireless connectivity in applications with limited Power and relaxed throughput requirements. Its applications are building automation, personal healthcare, industrial control, consumer electronics, and so on. Some applications require location information. Of course location awareness is useful to improve usability of data Low-Rate WPAN Is regarded as a key specification of the sensor network with the characteristics of wireless communication, computing, energy scavenging, self-networking, and etc. Unfortunately ZigBee alliance propose a lot of applications based on location aware technologies, but the specification and low-rate WPAN devices don't support anything about location-based services. RSSI ( Received Signal Strength indication) is for energy detection to associate, channel selection, and etc. RSSI is used to find the location of a potable device in WLAN. In this paper we studied indoor location awareness using vector matching of RSSI in low-Rate wireless PAN. We analyzed the characteristics of RSSI according to distance and experimented location awareness. We implemented sensor nodes with different shapes and configured the sensor network for the location awareness with 4 fixed nodes and a mobile node. We try to contribute developing location awareness method using RSSI in 3-dimension space.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 춘계 학술발표회 논문집
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• pp.1100-1109
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• 2006

In this study, two different technologies which can measure temperature simultaneously at many points are introduced. One is to use a thermal sensor cable that is comprised of addressable thermal sensors connected in parallel within a single cable. The other is to use an optic fiber with Distributed Temperature Sensing (DTS) system. The difference between two technologies can be summarized as follows. A thermal sensor cable has a concept of 'point sensing' that can measure temperature at accurate position of a thermal sensor. So the accuracy and resolution of temperature measurement are up to the ability of the thermal sensor. Whereas optic fiber sensor has a concept of 'distributed sensing' because temperature is measured by ratio of Stokes and anti-Stokes component intensities of Raman backscatter that is generated when laser pulse travels along an optic fiber. It's resolution is determined by measuring distance, measuring time and spatial resolution. The purpose of this study is that application targets of two temperature measurement techniques are checked in technical and economical phases by examining the strength and weakness of them. Considering the functions and characteristics of two techniques, the thermal sensor cable will be suitable to apply to the assessment of groundwater flow, geothermal distribution and grouting efficiency within 300m distance. It is expected that the optic fiber sensor can be widely utilized at various fields (for example: pipe line inspection, tunnel fire detection, power line monitoring etc.) which need an information of temperature distribution over relatively long distance.

• 전자통신동향분석
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• 제35권4호
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• pp.11-20
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• 2020

With the widespread use of high-performance electronics and mobile communications, electromagnetic interference (EMI) shielding has become crucial for protection against malfunctioning of electronic equipment and harmful effects to human health. In addition, smart sensor technologies will be rapidly developed in untact (non-contact) environments and personal healthcare fields. Herein, we introduce our recently developed technologies for flexible multifunctional EMI shielding, and highly sensitive wearable pressure-strain and humidity sensors realized using low-dimensional nanomaterials.