In steel manufacturing industry, as many advanced technologies increase manufacturing speed, fast and exact products inspection gets more important. This paper deals with a real-time defect detection algorithm for high-speed steel bar in coil (BIC). To get good performance, this algorithm has to solve several difficult problems such as cylindrical shape of a BIC, influence of light, many kinds of defects. Additionally, it should process quickly the large volumes of image for real-time processing since a steel bar moves at high speed. Therefore defect detection algorithm should satisfy two conflicting requirements of reducing the processing time and improving the efficiency of defect detection. This paper proposes an effective real-time defect detection algorithm that can solve above problems. And the algorithm is implemented by a high speed image processing system and will be applied to a practical manufacturing line. Finally, the performance of the proposed algorithm is demonstrated by experiment results.
It is important to estimate the intensity distribution of a magnetic field as a possible magnetic method in an industrial nondestructive evaluation application. A magnetic camera provides the distribution of a quantitative magnetic field with homogeneous lift-off and same spatial resolution. Magnetic flux leakage near a crack on the specimen can be amplified by using a 3- dimensional magnetic fluid, that is to say a magnetic lens. This study introduces the experimental consideration of the effects of magnetic lenses for concentrating of magnetic flux. The experimental results showed that the magnetic fluid has a sufficient lens effect for magnetic camera and effect of improvement in probability of detection.
It is important to estimate a magnetic field’ intensity distribution for the application of to industrial nondestructive evaluations. A magnetic camera provides the same spatial resolution and a distribution of a quantitative magnetic field with homogeneous lift-off. The method for arraying sensors is important on the magnetic camera because it must obtain a high spatial resolution. This work proposes an equation to evaluate the limitation of spatial resolution on the condition of the decided size of a magnetic sensor package. The possibility of obtaining the high spatial resolution in spite of the above-mentioned limitation would also be verified.
The linear source FMM evaporation can only provide 600ppi AMOLED devices because of the shadow effect so that new concept of FMM patterning technology is needed in order to fabricate the 2250ppi AMOLEDs. Recently, the plane source FMM evaporation techniques has been developed to show a dramatically suppressed shadow effect and to measure the 0.18um of shadow distance and Hwang's mixing for the new way of EML layer process. The green color OLED device has been fabricated by the plane source evaporation to study the emission property for the first time. In addition, the fabrication process of the plane source FMM evaporator has been discussed for the 2250ppi flexible AMOLED.
요 지 : 본 논문에서는 공정별 해상작업 가능 기간의 합리적 산출이 가능한 확률모형이 제시된다. 확률모형을 유도 하기 위해, 먼저 JMA(Japan Meterological Agency)와 NOAA(National Oceanic and Atmospheric Administration)의 해상풍 자료와 SWAN에 기초하여 2003년 1월 1일부터 2017년 12월 31일까지 한 시간 간격으로 울산 전면 해역에 서의 유의 파고와 첨두 주기를 역추산 하였다. 이어 모의된 유의파고 시계열 자료로부터 최소 자승법을 활용하여 장 기 유의파고 확률분포를 도출하였으며, 해석결과 그 동안 선호되던 삼 변량 Weibull 분포보다는 수정 Glukhovskiy 분포 계열에서 일치도가 가장 우월하였다. 보다 정확한 확률모형의 개발 가능성을 검토하기 위해 Borgman 선회적분 을 활용하여 역 추산 단위 간격인 한 시간 내에서 출현하는 개별 파랑이 고려된 파고분포도 함께 유도하였다. 수정 Glukhovskiy 분포의 모수는 A p = 15.92, H p = 4.374 m, κ p = 1.824로 드러났으며 해상작업 한계 파고가 H S = 1.5 m인 경우 작업가능일 수는 319일로 모의되었다. 이와 더불어 확률모형의 검증자료를 얻기 위해 파고가 해상 준설작업 한계 파고로 기 보고된 바 있는 H S = 1.5 m(Lee, 1991)를 상회하여 지속되는 시간을 유의파고 시계열 자료를 파별분 석(wave by wave analysis)하여 산출하였다. 산출결과 2003년부터 2017년까지의 평균 지속기간은 45.5일로 확률모형 으로부터 산출된 기간에 상당히 근접하였다. 핵심용어 : 복합 Weibull 파고분포, 해상작업 가능 기간, 수정 Glukhovskiy 분포, Borgman 적분, 고파랑 지속 시간, 전수조사Abstract : In this study, a probabilistic model for the estimation of yearly workable wave condition period for offshore operations is developed. In doing so, we first hindcast the significant wave heights and peak periods off the Ulsan every hour from 2003.1.1 to 2017.12.31 based on the meteorological data by JMA (Japan Meterological Agency) and NOAA (National Oceanic and Atmospheric Administration), and SWAN. Then, we proceed to derive the long term significant wave height distribution from the simulated time series using a least square method. It was shown that the agreements are more remarkable in the distribution in line with the Modified Glukhovskiy Distribution than in the three parameters Weibull distribution which has been preferred in the literature. In an effort to develop a more comprehensive probabilistic model for the estimation of yearly workable wave condition period for offshore operations, wave height distribution over the 15 years with individual waves occurring within the unit simulation period (1 hour) being fully taken into account is also derived based on the Borgman Convolution Integral. It is shown that the coefficients of the Modified Glukhovskiy distribution are A p = 15.92, H p = 4.374 m, κ p = 1.824, and the yearly workable wave condition period for offshore work is estimated to be 319 days when a threshold wave height for offshore work is H S = 1.5 m. In search of a way to validate the probabilistic model derived in this study, we also carry out the wave by wave analysis of the entire time series of numerically simulated significant wave heights over the 15 years to collect every duration periods of waves the height of which are surpassing the threshold height which has been reported to be H S = 1.5 m in the field practice in South Korea. It turns out that the average duration period is 45.5 days from 2003 to 2017, which is very close to 46 days from the probabilistic model derived in this study.
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