• Proceedings of the KIEE Conference
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• 2003.10a
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• pp.15-18
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• 2003

본 논문에서는 오손된 EPDM 배전용 현수애자에서 측정한 누설 전류의 파형을 분석하여 정확한 섬락 시기를 예측하기 위한 방법을 제안하였다. 이를 위하여 일정 시간 단위로 측정한 누설 전류들을 포락 한 후 레벨 교차율을 적용해 cdf 형태로 변환하였다. 획득된 cdf들은 서로 다른 기울기(각도)를 가지므로 애자의 섬락 시기를 예측하는데 유용하게 사용될 수 있다. 그러나 cdf들 간의 기울기 차는 매우 작아서 서로 구분되기 어려우므로 이를 해결하기 위하여 새로운 가중치를 정의하여 사용하였다. 실험 결과 제안한 방법은 배전용 현수애자의 섬락 시기를 적절히 예측할 수 있었다.

• Journal of Cadastre & Land InformatiX
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• v.45 no.2
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• pp.101-116
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• 2015

In Boundary Point Coordinate Register Area, the accuracy on Transformation of World Geodetic System(WGS) is determined by surveying results at the reference point. However, the present surveying result in reference points indicates the irregular performance due to the limitations of measurement techniques and methodologies, moreover, can be contaminated by various error sources from the unique characteristics of each project district and start time of the project. Therefore, the main purpose of present investigation is to conduct an inquest into error cause by project districts for each type in Boundary Point Coordinate Register Area, and propose the improvement plan of surveying accuracy through the WGS Transformation and verification-surveying.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.329-330
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• 2008

제주-해남간 HVDC 변환설비는 제주 전력수요의 약 40%를 담당하는 주요 설비로, 국내에서는 처음으로 도입되어 상용 운전중인 직류송전 설비이다. 10년간의 변환설비 운전중에 크고 작은 고장이 많이 발생하였으며 PCB Card에 의한 고장은 전체 고장의 약 30%를 차지하고 있다. 본 논문에서는 해남변환소에서 사용중인 VBE (Valve Base Electronics : Thyristor 점호 제어반) Cubicle에 설치된 Databack PCB Card 점검장비 개발내용을 설명하였다. 이 장비 사용시 설비사고 및 고장의 원인을 줄일 수 있고, 카드의 연도별 이력관리를 할 수 있다. 또한 Card의 경년열화 특성을 파악하여 교체시기를 판단할 수 있고 Card 시험시간의 단축이 가능하다. 상기 이외에 점검기술에 대하여 기존 방식과 비교하고 시험기 개발 및 운영사항에 대하여 기술하고자 한다.

• Journal of the Korea Society of Computer and Information
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• v.15 no.4
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• pp.91-98
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• 2010

Advances in communications and control technology, the strengthening of the Internet, and the growing recognition of the urgency to reduce the risk and production cost are motivating the development of improvements in the traditional manufacturing industry. In this paper, we developed a remote dust collector bag control system which is a combination of advanced IT and traditional dust collector based on the event. At first, we made the A/D(Analog/Digital) converter using a micro processor because the differential pressure transmission, which is a sensor of the dust collector, produces analog volt data. A/D converter can provide RS-232 communication to connect with Power Line Communication(PLC) modem. And, n-bytes message format was defined for the efficient dust collector bag information transmission from a dust collector to a user. Also, we designed the data types to model the dust collector and the dust collector bag, and they were logically modeled using XML and object-oriented modeling method. In addition to that, we implemented the system for showing the dust collector bag exchange time exactly to users at real-time using various visual user interfaces.

• Journal of Biomedical Engineering Research
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• v.22 no.2
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• pp.179-185
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• 2001

혈관에 발생하는 동맥 경화증은 그 발생 시기와 진행 정도를 예측하기 힘들어 초기 단계의 진단 및 치료가 어렵다. 이러한 이유로 혈관 질병의 진단은 많은 연구자들의 관심 대상이 되어왔고, 현재까지도 그 진단 장치 및 방법에 관한 연구가 활발히 진행되고 있다. 혈관 벽의 두께 측정은 혈관 질병을 진단할 수 있는 대표적인 지표이다. 그러므로 본 연구는 혈관 벽에서 수신되는 초음파 RF(Radio Frequency) 신호를 wavelet 변환하여 두께를 측정할 수 있는 방법을 제안한다. 시뮬레이션 결과를 토대로 두께가 각각 0.53mm, 1.2mm인 고분자 물질을 가지고 두께측정 실험을 행하였다. 기존의 방법인 주파수 스펙트럼법과 제안한 방법인 wavelet 변환법에 의하여 측정된 평균 두께는 0.53mm인 경우 각각 0.670$\pm$0.168mm(79.10%), 0.448$\pm$0.084mm(84.53%)이고, 1.2mm인 경우 각각 0.962$\pm$0.072mm(80.17%), 1.149$\pm$0.066mm(95.15%)이다. In-vitro 실험을 행하기 위하여 한천, gelatin, SiC 결정을 가지고 두께가 0.85mm인 혈관 유사 시편을 제작하였고, 이 시편으로부터 데이터를 획득하여 이를 제안한 방법으로 두께를 측정하였다. 그 결과 제안한 방법으로 측정된 평균 두께는 0.8008$\pm$0.0154mm(94.22%)이다. 결론적으로 wavelet 변환을 통해서 혈관 벽의 두께를 정밀하게 측정할 수 있는 가능성이 있음을 알 수 있다.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.739-740
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• 2001

DNA microarray with a set of 37 Corynebacterium glutamicum genes encoding enzymes for primary metabolism of glycolysis, TCA cycle and lysine biosynthesis, anaplerosis etc was constructed on slide glass in triplicate. With this DNA microarray, metabolic characteristics of the lysine-producing strain was analyzed during different phase of the cultivation. The major differences in using glucose as a carbon source instead of sucrose was found in the anaplerolytic enzymes, which control the interconversion of C3 and C4 metabolites. Also, the expression profile of these major enzymes was found to be quite distinct among different phases of growth.

• Journal of Biomedical Engineering Research
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• v.24 no.2
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• pp.61-68
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• 2003

This paper presents a quantitative analysis method for fall in sick times of the cerebral infarction patients using three types of magnetic resonance image, which play an important role in deciding method of medical treatment. For this object, image characteristics obtained by three radiographic methods of MRI and their relation were analyzed by means of object centered hierarchical Planning method. This methode presents an approach to the knowledge based processes for image interpretation and analysis. To compare three type of MRI. a multiple warping algorithm and affine transform method performed for image matching. Then each fall in sick times level of cerebral infarction was quantified and pseudo-color mapping performed by comparing gray level value one another according to Previously obtained hand maid data. The result of this study was compared to a medical doctors decision.

• Smart Media Journal
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• v.6 no.2
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• pp.33-41
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• 2017

Railway point machines act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Since point failure caused by the aging effect can significantly affect railway operations with potentially disastrous consequences, replacement detection of point machine at an appropriate time is critical. In this paper, we propose a replacement condition detection method of point machine in railway condition monitoring systems using electrical current signals, after analyzing and relabeling domestic in-field replacement data by means of OLAP(On-Line Analytical Processing) operations in the multidimensional data cube into "does-not-need-to-be replaced" and "needs-to-be-replaced" data. The system enables extracting suitable feature vectors from the incoming electrical current signals by DWT(Discrete Wavelet Transform) with reduced feature dimensions using PCA(Principal Components Analysis), and employs SVM(Support Vector Machine) for the real-time replacement detection of point machine. Experimental results with in-field replacement data including points anomalies show that the system could detect the replacement conditions of railway point machines with accuracy exceeding 98%.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5D
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• pp.483-492
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• 2012

The early setting time of concrete is an important factor determining the slip up velocity of the slip-form system. Accordingly, need is for a technique evaluating the early setting time in order to secure the safety of the slip-form system and the construction quality of concrete. This paper intends to estimate the early setting time by evaluating the setting degree of concrete using surface wave velocity so as to determine the slip up time of the slip-form system. Penetration resistance test and compressive strength test are performed first to clarify the relationship between the early setting time of concrete and the compressive strength. Then, compressive strength test and ultrasonic wave test are conducted to examine the relation between the compressive strength and the surface wave velocity. Continuous wavelet transform is adopted to measure the surface wave velocity. Numerical analysis is carried out to demonstrate the appropriateness of the application of continuous wavelet transform. Based on these results, the propagation velocity of the surface wave required for the slip up of slip-form system is suggested. Finally, a reduced model test of the slip-form system is conducted to verify the feasibility of the proposed surface wave velocity for the determination of th slip up velocity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.1 no.1
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• pp.29-37
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• 2002

The wavelet transform is a popular tool for studying intermittent and localized phenomena in signals. In this study the wavelet transform of cutting force signals was conducted for the diagnosis of grinding conditions in grinding process. We used the Daubechies wavelet analyzing function to detect a sudden change in cutting signal level. STD11 workpiece was 85 times of machined pieces cut by the WA wheel and a tool dynamometer obtained cutting force signals. From the results of the wavelet transform, the obtained signals were divided into approximation terms and detailed terms. At dressing time, the approximation signals were slowly increased and 45 machined times noticed dressing time.