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오픈-소스 자료처리 기술개발 소프트웨어(Madagascar)를 이용한 탄성파 현장자료 전산처리 적용성 연구
손우현 ( Woohyun Son ),김병엽 ( Byoung-yeop Kim ) 한국지구물리·물리탐사학회 2018 지구물리와 물리탐사 Vol.21 No.3
We performed the seismic field data processing using an open-source software (Madagascar) to verify if it is applicable to processing of field data, which has low signal-to-noise ratio and high uncertainties in velocities. The Madagascar, based on Python, is usually supposed to be better in the development of processing technologies due to its capabilities of multidimensional data analysis and reproducibility. However, this open-source software has not been widely used so far for field data processing because of complicated interfaces and data structure system. To verify the effectiveness of the Madagascar software on field data, we applied it to a typical seismic data processing flow including data loading, geometry build-up, F-K filter, predictive deconvolution, velocity analysis, normal moveout correction, stack, and migration. The field data for the test were acquired in Gunsan Basin, Yellow Sea using a streamer consisting of 480 channels and 4 arrays of air-guns. The results at all processing step are compared with those processed with Landmark’s ProMAX (SeisSpace R5000) which is a commercial processing software. Madagascar shows relatively high efficiencies in data IO and management as well as reproducibility. Additionally, it shows quick and exact calculations in some automated procedures such as stacking velocity analysis. There were no remarkable differences in the results after applying the signal enhancement flows of both software. For the deeper part of the substructure image, however, the commercial software shows better results than the open-source software. This is simply because the commercial software has various flows for de-multiple and provides interactive processing environments for delicate processing works compared to Madagascar. Considering that many researchers around the world are developing various data processing algorithms for Madagascar, we can expect that the open-source software such as Madagascar can be widely used for commercial-level processing with the strength of expandability, cost effectiveness and reproducibility.
스트리머 방식 탐사 자료의 동시 송신원 전파형 역산을 위한 Global correlation 기반 목적함수 최적화 연구
손우현 ( Woo Hyun Son ),편석준 ( Suk Joon Pyun ),장동혁 ( Dong Hyuk Jang ),박윤희 ( Yun Hui Park ) 한국지구물리·물리탐사학회 2012 지구물리와 물리탐사 Vol.15 No.3
The simultaneous-source full waveform inversion improves the applicability of full waveform inversion by reducing the computational cost. Since this technique adopts simultaneous multi-source for forward modeling, unwanted events remain in the residual seismograms when the receiver geometry of field acquisition is different from that of numerical modeling. As a result, these events impede the convergence of the full waveform inversion. In particular, the streamer-type data with limited offsets is the most difficult data to apply the simultaneous-source technique. To overcome this problem, the global-correlation-based objective function was suggested and it was successfully applied to the simultaneous-source full waveform inversion in time domain. However, this method distorts residual wavefields due to the modified objective function and has a negative influence on the inversion result. In addition, this method has not been applied to the frequency-domain simultaneous-source full waveform inversion. In this paper, we apply a timedamping function to the observed and modeled data, which are used to compute global correlation, to minimize the distortion of residual wavefields. Since the damped wavefields optimize the performance of the global correlation, it mitigates the distortion of the residual wavefields and improves the inversion result. Our algorithm incorporates the globalcorrelation- based full waveform inversion into the frequency domain by back-propagating the time-domain residual wavefields in the frequency domain. Through the numerical examples using the streamer-type data, we show that our inversion algorithm better describes the velocity structure than the conventional global correlation approach does.
손우현 ( Woo Hyun Son ),편석준 ( Suk Joon Pyun ),곽상민 ( Sang Min Kwak ) 한국지구물리·물리탐사학회 2011 지구물리와 물리탐사 Vol.14 No.3
We perform the frequency-domain waveform inversion based on the residual-selection strategy. In the residualselection strategy, we classify time-domain residual wavefields into several groups according to the order of absolute amplitudes. Because the residual wavefields are normalized after regularization of the gradient directions within each group, the residual-selection strategy plays a role in enhancing the small-amplitude wavefields, which contributes to improving the deep parts of inverted subsurface images. After classifying residuals in the time domain, they are transformed to the frequency domain. Waveform inversion is performed in the frequency domain using the backpropagation technique which has been popularly used in reverse-time migration. The residual-selection strategy is applied to the SEG/EAGE salt and IFP Marmousi models. Numerical results show that the residual-selection strategy yields better results than the conventional frequency-domain waveform inversion.
손우현,박상진,정재영,김재혁,빈향욱,목학수,Son, Woo Hyun,Park, Sang Jin,Jeong, Jae Yeong,Kim, Jae Hyuk,Bin, Hyang Wook,Mok, Hak Soo 한국자원리싸이클링학회 2016 資源 리싸이클링 Vol.25 No.4
전 세계적으로 자동차 산업에서 사용된 제품을 위한 재제조는 신제품에 비해 에너지와 자원 소모율을 크게 감소시킬 수 있는 장점을 가지고 있다. 본 논문에서는 자동차 부품중 하나인 스로틀바디를 대상으로, 재제조 세부 공정을 분석하고, 각 세부 공정별 고장모드 및 이에 대한 FMEA 도출 및 많은 고장유형에 대한 심각도, 검출도, 발생도의 정도를 결정하는 것이다. 그리고 RPN값을 계산하는데 사용되고 있는 현재 RPN방법과 제안하고자 하는 세 가지 방법인 합산법, 제곱근법, 볼륨법에 대하여 비교하고자한다. In global automobile industry, the remanufacturing for used products has the merit to be reduced nearly 80 percent of energy consumption and resources of new product. The objective of this paper is the analysis of detailed remanufacturing processes about research object and failure modes of each process of throttle body which is one of automobile parts, to draw a FMEA and determine the degree of seriousness (S), detection (D) and occurrence (O) of many failures. And we compared the current RPN method of being used to calculate values of RPN with three suggested methods. : Summation method, Square root method, Volume method.