• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 가을 학술발표논문집 Vol.31 No.2 (3)
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• pp.142-144
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• 2004

To provide more qualified data service on the HFC(Hybrid-Fiber Coaxial) access network, the channel characteristics of upstream transmission band should be carefully investigated and analysed. It will be easier to do network management if the monitoring system for noise measurement in the network is available, In this paper, noise analysis method and the frequency selection method in the upstream band for duplex transmission are suggested. And, Data aquisition device for the signal measurement Is implemented. With this network monitoring system, field test and the result from the collected data are described.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.505-524
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• 2010

Wireless structural monitoring systems consist of networks of wireless sensors installed to record the loading environment and corresponding response of large-scale civil structures. Wireless monitoring systems are desirable because they eliminate the need for costly and labor intensive installation of coaxial wiring in a structure. However, another advantageous characteristic of wireless sensors is their installation modularity. For example, wireless sensors can be easily and rapidly removed and reinstalled in new locations on a structure if the need arises. In this study, the reconfiguration of a rapid-to-deploy wireless structural monitoring system is proposed for monitoring short- and medium-span highway bridges. Narada wireless sensor nodes using power amplified radios are adopted to achieve long communication ranges. A network of twenty Narada wireless sensors is installed on the Yeondae Bridge (Korea) to measure the global response of the bridge to controlled truck loadings. To attain acceleration measurements in a large number of locations on the bridge, the wireless monitoring system is installed three times, with each installation concentrating sensors in one localized area of the bridge. Analysis of measurement data after installation of the three monitoring system configurations leads to reliable estimation of the bridge modal properties, including mode shapes.

• 전자공학회논문지A
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• 제31A권10호
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• pp.10-20
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• 1994

This paper presents a CATV SMS (Status Monitoring System) using HDLC (High Level Data Link Contorl) protocol and the system implementation.The system specifications were derived from the analysis of technical status and requirement of the domestic CATV industry. For the interoperability with a global network management system in the future, HDLC protocol was adopted in the system. The system performance was improved by using the communication controller chip and the large data buffer. For reducting the communication problems induced by accumulated noise in up-stream data channels, the system was designed that the different communication channel can be assigned to each proper mass of terminal. The operating software was designed with menu driven user interface and have various functions for the convenience of users. The test result of the implemented system at the experimental network showed good performance and suitability for a coaxial CATV Status Monitoring System.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.116-119
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• 2004

The existing monitoring and control systems of utility-pipe conduit (power tunnel, cable tunnel etc) have established communication lines using optical fiber, leaky coaxial cable (LCX), and several kinds of control cable. Due to the properties of the used media, the cost of equipment is considerably high and the maintenance of the system is difficult. Also, the term of carrying out is long so that the extension of the system is in difficulty. Now it is desirable to adopt Power Line Communication (hereinafter, PLC) technology in the monitoring and control systems and use the existing low-voltage power-line for lamplight as communication line. This will lead the reduction of the construction cost and the easy maintenance of the system. In this paper, we research the characteristics of PLC in conduit, design and manufacture the field test system, and analyze the performance of the system by field test. Then, we introduce the reliable monitoring and control system of utility-pipe conduit using PLC.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.560-562
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• 2017

본 논문에서는 최근 택배 유인드론의 개발 등 높은 유상하중을 요구하는 임무를 수행하기 위해 드론에 적용되고 있는 동축반전 프로펠러의 제자리 비행성능을 확인하기 위한 시험 장치 개발과 시험 결과를 제시하였다. 프로펠러 직경 대비 상/하 프로펠러 간격에 따른 각 추력과 토크의 변화를 측정하여 성능을 비교하였다. 프로펠러가 회전할 때 발생하는 추력, 토크를 측정하기 위해 로드셀과 토크셀을 이용하였고 회전수를 측정하기 위해서 광센서를 이용하였다. 각 센서의 신호획득을 위해 자료획득시스템(Data Acquisition System)을 이용하고 신호 저장, 모니터링과 BLDC 모터를 제어할 수 있도록 LabVIEW소프트웨어를 활용하였다. 시험은 각 프로펠러가 동일 회전수에서 간격 변화에 따른 성능지수(Figure of Merit)를 측정하였다.

• 한국전자통신학회논문지
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• 제16권4호
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• pp.763-770
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• 2021

본 논문에서는 ISM 대역에서 동작하는 BAN(Body Area Network) 신호의 영향을 배제하기 위해서 4.567 GHz에서 작동하는 온 바디 마이크로스트립 패치 안테나의 설계 및 최적화 과정을 제시하였다. 하지 해면골 골다공증 감시를 위한 이 안테나는 향상된 반사손실 및 대역폭을 가지면서, 경박단소하도록 설계하였다. 적용된 하지 주변 구조는 5층 유전체 평면으로 구조화 하였으며, 손실을 고려한 각층의 복소유전상수는 다중 Cole-Cole 모델 매개변수를 사용하여 계산하였으나, 정상 및 골다공증 해면골은 단극형 모델을 사용하였다. 팬텀상 동축급전 안테나의 반사손실은 4.567 GHz에서 -67.26 dB이고, 골다공증 경우 동일 주파수에서 반사손실차 𝚫S₁₁=35.88 dB이고, 공진 주파수 차는 약 7 MHz이다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.79-86
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• 2010

In this paper, using soil slope inclinometer observations of lateral flow is used as a traditional way, but there are some decisions. Inclinometers in the process of installing and monitoring is costly. Severe incline slope of the lateral flow is observed in the inefficient. As a solution for it using TDR sensors are used to. Metal conductors such as coaxial cable and general cable uses a measurement sensor can be installed on site at a lower cost and slope measurements are available for long-term monitoring. When TDR sensor is installed on the slopes, changes in the behavior of slopes causes the earth pressure. TDR sensors determine the change of earth pressure and tried to analyze the behavior of slopes.

• Smart Structures and Systems
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• 제10권1호
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• pp.1-14
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• 2012

Given an object, its positioning in the space is a main concern in structural monitoring and a required feedback in structural health monitoring, structural control and robotics. In addition, to make the sensor unit wireless is a crucial issue for advanced applications. This paper deals with the exploitation of wireless transmission technology to long-term monitoring GPS (Global Positioning System) receivers - like the Leica GMX 902 and the Leica GRX 1200-pro. These GPS receivers consist of five parts: antenna, receiver, user client computer, interface and power supply. The antenna is mounted on the object to be monitored and is connected with the receiver by a coaxial-cable through which the radio frequency signals are transmitted. The receiver unit acquires, tracks and demodulates the satellite signals and provides, through an interface which in this paper is made wireless, the resulting GPS raw data to the user client computer for being further processed by a suitable positioning algorithm. The power supply reaches the computer by a wired link, while the other modules rely on batteries re-charged by power harvesting devices. Two wireless transmission systems, the 24XStream and the CC1110, are applied to replace the cable transmission between the receiver and the user client computer which up to now was the only market offer. To verify the performance and the reliability of this wireless transmission system, some experiments are conducted. The results show a successful cable replacement.

• 한국산학기술학회논문지
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• 제11권3호
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• pp.1101-1107
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• 2010

VCR에 비해 성능이 우수하여 DVR이 보안 모니터링 시스템에 활발히 사용되고 있다. 본 논문에서는 기존 DVR의 성능을 향상시킬 수 있는 DVR 인터페이스와 중계 장치를 설계 구현하여 대규모 보안감시시스템을 경제적으로 구축할 수 있도록 하였다. 본 논문의 중계 장치는 8대의 감시 단말기를 DVR 두 채널에 수용하며, 한 개의 DVR 인터페이스는 16개의 중계 장치를 관리하여 총 128대의 감시 단말기를 수용할 수 있다. 결국, 본 시스템은 기존 시스템보다 4배의 시스템 확장성을 가지며, DVR 인터페이스, 중계 장치 및 감시 단말기 사이의 연결에 동축 케이블 대신 저렴한 UTP 케이블을 사용할 수 있도록 하여 설치비용을 대폭 절감할 수 있다. 또한 본 보안 모니터링 시스템은 영상전송, 음성통화, 비상호출, RFID 카드 등의 다양한 기능들이 하나로 통합되어 있어, 다양한 환경과 조건에서 효과적으로 사용될 수 있다.

• 한국정밀공학회지
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• 제22권7호
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• pp.27-37
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• 2005

Direct writing technology on the silicon wafer surface is used to reduce the size of the chip as the miniature trend in electronic circuit. In order to improve the productivity and efficiency, the real time quality estimation is very important in each semiconductor process. In laser marking, marking quality is determined by readability which is dependant on the contrast of surface, the line width, and the melting depth. Many researchers have tried to find theoretical and numerical estimation models fur groove geometry. However, these models are limited to be applied to the real system. In this study, the estimation system for the line width during the laser marking was proposed by process monitoring method. The light intensity emitted by plasma which is produced when irradiating the laser to the silicon wafer was measured using the optical sensor. Because the laser marking is too fast to measure with external sensor, we build up the coaxial monitoring system. Analysis for the correlation between the acquired signals and the line width according to the change of laser power was carried out. Also, we developed the models enabling the estimation of line width of the laser marking through the statistical regression models and may see that their estimating performances were excellent.