• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.3
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• pp.246-259
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• 2011

This study presents a structural health monitoring (SHM) method for bolted connections by using multi-channel wireless impedance sensor nodes and multiple PZT-interfaces. To achieve the objective, the following approaches are implemented. Firstly, a PZT-interface is designed to monitor bolt loosening in bolted connection based on variation of electro-mechanical(EM) impedance signatures. Secondly, a wireless impedance sensor node is designed for autonomous, cost-efficient and multi-channel monitoring. For the sensor platform, Imote2 is selected on the basis of its high operating speed, low power requirement and large storage memory. Finally, the performance of the wireless sensor node and the PZT-interfaces is experimentally evaluated for a bolt-connection model Damage monitoring method using root mean square deviation(RMSD) index of EM impedance signatures is utilized to estimate the strength of the bolted joint.

• Proceedings of the IEEK Conference
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• 2003.07a
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• pp.569-572
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• 2003

The broadband wireless access industry, which provides high-tate network connections to stationary sites, has matured to the point at which it now has a standard for second-generation wireless metropolitan area networks. IEEE Standard 802.16, with its WirelessMAN air interface, set the stage for widespread and effective deployments worldwide. This paper presents an implementation of media access control that can be applied to BWA (Broadband Wireless Access) system. Medium access control (MAC) is a key issue in multi-access networks where a common channel is shared by many users. The designed MAC prototype roughly consists of MAC Hardware and MAC Software. The MAC Hardware part includes timing process, MAC transmission control, MAC reception control, and CRC/HCS process. The MAC Software part includes control of MAC signaling, network interface, and Physical (PHY) control. The designed MAC protocol will be integrated with the PHY of BWA in future and we can test overall system performance of MAC and PHY.

• Journal of the Korea Society of Computer and Information
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• v.8 no.2
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• pp.122-128
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• 2003

There are many development methods to implement wireless internet service. These methods are WAP(Wireless Application Protocol) based services and Java based service WAP based service has been proposed to support limited convenience for user But Java based service can support many convenience and GUI(Graphic User Interface) and easy to use to access for user. This paper will be propose a WAP based application development method and Java based application development method. As an illustrative experiment, WAP based service and Java based service are used to show performance for each systems.

• Information and Communications Magazine
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• v.24 no.8
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• pp.40-52
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• 2007

본고에서는 비/저활용(57-66GHz) 대역에 대한 새로운 주파수 자원을 개척하여 HDTV급 신호를 케이블 및 위성방송 셋톱박스, 게임콘솔, DVD플레이어, 캠코더 및 이동식 멀티미디어 장비와 무선으로 연결시키는 전송 기술 개발을 위하여 Intel, Philips, Motorola, IBM, SiBeam, Panasonic, Sony등 세계적인 기업들이 국제 표준화(IEEE802.15, ETSI/BRAN, ECMA International) 공동 협력 및 기술 개발 경쟁을 벌이고 있는 상황이다. 본 표준기술은 국내 기업이 세계 시장을 장악하고 있는 LCD, PDP 및 차세대 DVD플레이어 등에 적용될 Wireless HD-SDI(High Definition Serial Data Interface)/ DVI(Digital Visual Interface)와, 외장 하드 디스크, 메모리 등 외부 기억 장치와의 자원 공유에 사용될 Muti-Gbps급 Wireless LAN, Wireless PAN, Wireless SAN(System Area Network) 등에 적용될 무선 전송 기술이다. 비/저활용 $59{\sim}66GHz$ 대역에 대한 국제 표준화로 IEEE802.15.3c를 중심으로 활발히 일어나고 있는 표준기술과 표준화 동향을 살펴본다.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.130-134
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• 2012

This paper introduces a home network service system using a low-cost wireless router on OpenWrt which can be remotely controled by Android devices. The proposed system consists of an embedded system development platform for home network service control based on OpemWrt embedded Linux, an embedded system development platform, a remote control on Android, and a home linghting device made by an interface board with LEDs. The prototype system is made of a wireless router of Buffalo, WZR-HP-G450H, Arduino Uno interface board with LEDs, and an Android development kit of HBE-SM5-S421. The operation was performed by TCP/IP programming for Android remote control, socket programming between Android development kit and wireless router, and UART communication programming between the interface board and wireless router. The implementation result shows that a low cost home network systme could be implemented with a wireless router.

• Archives of design research
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• v.17 no.1
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• pp.49-62
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• 2004

Due to the recent surge of wireless Internet and concurrent development of the end user terminal devices having standardized graphical user interface(GUI) and unified operation mechanism for better interactivity in information representation and ease of use, various efforts on the improvement of GUI is widely recognized as one of the key factors that will usher in the next stages of the wireless Internet for the users. Especially, improved usability along with unique visual effect are considered to be the key elements for GUI considering the rapid improvement of the resolution and color on the end user handset devices; thus, the study and research on the subject of GUI is expected to increase along with the wireless Internet using smart phones. User interface of the wires Internet end user handsets will have a definite and significant effect on the user interaction as well as productivity. Domestically, wireless Internet service providers and GUI design companies are making various efforts in producing a common GUI models for standardized operation scheme and improved graphical display capabilities of the hand phones, PDAs and smart phones. In the study, Nokia 3650 model and Microsoft Orange SPV model were chosen as test devices for usability comparison and data collection to collect directional benchmark data in developing next generation smart phone user interface integrating PDAs and phones. The mail purpose of this study is to achieve the most efficient user accessibility to WAP menu through intensive focus on developing WIPI WAP menu having most effective usability for the users in their twenties and thirties. The result of this study can also be used as the base research materials for WAP service development, VM browser development and PDA browser development. The result of this study along with the evaluation model is expected to provide effective analysis materials on the subject of user interface to the developers of the wireless Internet user devices, GUI designers and service planners while short listing key factors to consider in developing smart phones therefore serving as the GUI guideline of WIPI phones.

• Journal of the Korean Institute of Intelligent Systems
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• v.17 no.3
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• pp.336-342
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• 2007

Industrial HMI(Human Machine Interface) system is the main element among the factory automation processes and have been used to monitor and control operation and status of machine in factory with PLC. This HMI often brings heavy loads to the system development and difficult decreasing the system because it tends to use a specific system per each manufacturer. Therefore, in this thesis, we have developed an embedded linux-based embedded industrial HMI software modules which can be used for touch panel embedded system to solve these problem. In this module, we have used the Qt/Embedded software component because it can be used by all systems which support C++ compiler without modifying the existing codes. We can design more flexible system and network configuration because we have used the wireless communication module. In this thesis, we implement linux-based HMI software modules which are capable of wireless communication as well as bringing the mobility to the overall system and finally decreasing the system development loads by using the general purpose OS with competitive price.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.4
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• pp.839-847
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• 2014

A recent major development in computer technology is the advent of the wearable computer system that is based on human-centric interface technology trends and ubiquitous computing environments. Wearable computer systems can use the wireless universal serial bus (WUSB) that refers to USB technology that is merged with WiMedia PHY/MAC technical specifications. In this paper, we focus on an integrated system of the wireless USB over the wireless body area networks (WBAN) for wireless wearable computer systems supporting U-health services. To construct the WUSB over WBAN communication systems, we propose a WBAN beaconing structure to assign WUSB communication periods. In the proposed structure, WUSB uses private periods of WBAN. In our performance evaluations, we compare theoretical results and simulation results about throughputs of WUSB under various WBAN channel occupations to evaluate the effectiveness of proposed structure in WUSB over WBAN communications.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.9 no.5
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• pp.53-63
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• 2009

This paper is to develop WiMAX CPE(wireless AP) that can provides Wi-Fi terminal with wireless Internet service by connecting to Wibro wireless network. This AP aims to support WiBro in upstream interface basically, and Wi-Fi and 100M Ethernet interface in downstream. So, we has developed the equipment for business that wireless ISP can provide many Internet customers with wireless Internet service by using Wi-Fi terminal in subway, car, ship, and so on, and the equipment for users that a user can purchase and then install in person. For the latter, multiple Wi-Fi terminals that be registered in WiBro service can be connected to Internet simultaneously.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.229-235
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• 2017

Until now, a study on a ubiquitous sensor network has been mainly concentrated in the areas of sensor nodes, and as a results, technologies related with sensor node were greatly developed. Despite of many achievements on research and development for a sensor node, a ubiquitous sensor network may failed to establish the actual service environment because variety of restrictions. In order to provide a actual service using a ubiquitous sensor networks applied to many results on research and development for a sensor nodes, a study on a wired/wireless composite router must be carried out. However a study on a wired/wireless composite router is relatively very slow compared with the sensor node. In this study, developed a high-performance router platform supporting IPv6 that can provide high-speed wired/wireless interface and QoS, and it can provide the multimedia service Interlocking the wireless sensor network and the Internet network. To analysis a given network environment and to develop the appropriate hardware and software in accordance with this requirement.