• Journal of the Optical Society of Korea
• /
• 제16권3호
• /
• pp.215-220
• /
• 2012

In an earlier work, we proposed the chromatic dispersion monitoring technique of non-return to zero (NRZ) signal based on clock-frequency component (CFC) through numerical simulations. However, we have not yet shown any experimental demonstration or analytic derivation of it. In this paper, we show an experimental demonstration and analytic derivation of the proposed chromatic dispersion monitoring technique. We confirm that the experimental results and the analytic results correspond with the simulation results. We also demonstrate that monitoring range and accuracy can be improved by using a simple clock-extraction method.

• 정보처리학회논문지D
• /
• 제13D권4호
• /
• pp.613-618
• /
• 2006

임베디드 소프트웨어의 적용범위가 넓어짐에 따라 소프트웨어의 개발시간을 줄이기 위한 많은 개발도구가 개발되었다. 하지만, 기존 도구들은 특정 플랫폼 적용을 목적으로 개발되었기 때문에 적용 가능한 범위가 제한된다. 이러한 문제 해결을 위하여 다양한 통신 환경을 지원함으로써 플랫폼 제약을 제거한 임베디드 모니터링 시스템을 개발하였다. 임베디드 모니터링 시스템은 코드 인라인 기법을 통하여 모니터링 과정을 진행한다. 하지만, 코드 인라인 기법은 모니터링 센서의 수행에 대한 부하문제를 가지고 있기 때문에 모니터링 센서의 최적화에 대한 고려가 필요하다. 이에 본 논문에서는 모니터링 과정 초기화 방안과 모니터링 센서 최적화를 위한 비트마스킹 기법을 제안한다. 개발된 임베디드 모니터링 시스템은 임베디드 시스템을 사용하는 모든 분야에 적용가능하다.

• 전기학회논문지P
• /
• 제57권2호
• /
• pp.176-180
• /
• 2008

A field-oriented UHF system for on-line PD monitoring of transformers is designed, which has been installed inside the oil tank of transformer in a substation by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.829-834
• /
• 2004

This research is to development advanced health(condition) monitoring system of superconducting motors. Development of advanced condition monitoring systems offers the prospect of improved performance, assessment, and operation, simplified design, enhanced safety, and reduced overall cost of advanced and next generation superconducting motor. For advanced and next generation superconducting motor design, the opportunity exists to develop and implement real-time and continuous monitoring systems by integrating wireless and computational technique. Generally, condition monitoring and control of temperature is essential for managing the superconducting motor components, rotor and structures. In this research, development of advanced monitoring in low temperature and high speed operating environments offers the potential to greatly improve the control of harsh environments. In conventional method, slip rings have been used to acquire data from these sensors. However, the increase of sensors leads to vibration of the rotation axis and noise signals due to kinematics contact. In this study, the wireless data acquisition technique was employed to develop more stable monitoring system adequate for high speed rotating system.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.599-602
• /
• 2000

A new dressing technique with utilizes electrolytic phenomenon for realizing effective mirror surface grindings with metal bonded super-abrasive wheels is called “Electrolytic In-process Dressing Grinding”. This technique enabled metal bonded micro-grain wheels, such as micro-grain cast iron fiber bonded wheels, to be used for mirror surface finish processes effectively. But this technique requires a lot of knowledge and experience to perform. And the condition of dressing is variable according to the time. Therefore adaptation of Monitoring and Control technique is needed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 제39회 하계학술대회
• /
• pp.2116-2117
• /
• 2008

This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2008년도 춘계학술대회 논문집 센서 박막재료연구회 및 광주 전남지부
• /
• pp.115-118
• /
• 2008

A field-oriented UHF system for on-line PD monitoring of transformers. is designed, which has been installed inside the oil tank of a transformer by two ways: on-line installing mode through the oil-valve and pre-installing mode through the man hole/hand hole cover. This system has successfully captured long intermittent discharge signals that hadn't been detected through conventional techniques, and solved the problem successfully. The results demonstrate that UHF technique has great advantages for on-line PD monitoring of transformers. By adopting the peak detection technique, it becomes easy and effective for the transplantation of the phase-resolved pattern recognition technique from conventional method to UHF method, and then to realize continuous on-line monitoring, source characterization and trending analysis.

• 한국레이저가공학회지
• /
• 제4권2호
• /
• pp.29-38
• /
• 2001

A development of in-process and reliable monitoring system in laser materials processing is essential for successful applications toward the real industrial fields. It was known that optical signals induced by laser-matter interactions provide a good indication not only to monitor various defects but also to characterize and identify the process However there are still difficulties to implement the optical monitoring system in real fields since the system is susceptible to the spurious change of the signal affected by the variation of experimental conditions and environmental noises. In this article. a new type of optical monitoring technique named 'chromatic modulation technique' is described as a reliable, robust and sensitive monitor for the applications in laser materials processing in order to tackle the conventional problems in optical system.

• Smart Structures and Systems
• /
• 제12권3_4호
• /
• pp.381-397
• /
• 2013

In this paper, wireless health monitoring of stay cables using piezoelectric strain sensors and a smart skin technique is presented. For the cables, tension forces are estimated to examine their health status from vibration features with consideration of temperature effects. The following approaches are implemented to achieve the objective. Firstly, the tension force estimation utilizing the piezoelectric sensor-embedded smart skin is presented. A temperature correlation model to recalculate the tension force at a temperature of interest is designed by correlating the change in cable's dynamic features and temperature variation. Secondly, the wireless health monitoring system for stay cables is described. A piezoelectric strain sensor node and a tension force monitoring software which is embedded in the sensor are designed. Finally, the feasibility of the proposed monitoring technique is evaluated on stay cables of the Hwamyung Grand Bridge in Busan, Korea.

• Journal of the Optical Society of Korea
• /
• 제13권1호
• /
• pp.112-115
• /
• 2009

We investigate the effect of polarization-mode dispersion (PMD) on the optimum dispersion compensation (ODC) monitoring and nonlinear penalty in optical transmission systems. We report that PMD may reduce the fiber nonlinearity. We also report that the monitoring error of the clock-based ODC monitoring technique decreases after the first-order PMD compensation. A simple explanation of this phenomenon is shown.