3,575,868 research outputs found
sj-rar-1-pid-10.1177_09544070221135390 – Supplemental material for Electro-hydraulic braking dynamics for pressure demand control of brake-by-wire system
No full textSupplemental material, sj-rar-1-pid-10.1177_09544070221135390 for Electro-hydraulic braking dynamics for pressure demand control of brake-by-wire system by Ligao Jiang, Qin Shi, Yujiang Wei, Yunfeng He, Zejia He and Lin He in Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering</p
Qiong han ling.
No full text白玉江[等]執筆 ; 大連市寺兒溝區大糞合作社集體創作.Play.五幕劇本電子書乃根據《香港版權條例(第528章)》而複製, 並只可在大學圖書館系統內的獨立電子書系統上使用.Bai Yujiang [deng] zhi bi ; Dalian Shi shi er gou ju da fen he zuo she ji ti chuang zuo.Ben dian zi shu nai gen ju "Xianggang ban quan tiao li (Di 528 zhang)" er fu zhi, bing zhi ke zai da xue tu shu guan xi tong nei de du li dian zi shu xi tong shang shi yong.Detailed notes in vernacular field only
Predicting the distribution of reservoirs by combining variable wavelet model of seismograms with wavelet edge analysis and modeling
No full textReservoir prediction with its unique role in oil and gas fields is constantly facing new challenges, such as high-resolution seismic data and fast-accurate impedance inversion are needed. Generally, conventional methods used to enhance the resolution of seismic data, for example the spectral whitening, sometimes called balancing or broadening, is hard to yield valuable results as the seismic wavelets change during traveling subsurface. Besides, impedance inversion used in reservoir such as acoustic impedance inversion (AII) also confronts problem—low computational efficiency when more geological and geophysical parameters are taken into consideration in the modeling inversion. Based on these questions, in this study, a joint approach is presented. The first approach is the variable wavelet model of seismograms (VWMS), which is carried out by a series of processes such as time partition and frequency domain processing, to enhance the resolution of the seismic traces. Another approach that can improve the computational efficiency of the AII is the acoustic impedance inversion based wavelet edge analysis and modeling (AII-WEAM). In this approach, the algorithms of the AII were replaced by the modified very fast simulated annealing (MVFSA), to improve the inversed speed. By using a gas reservoir predicting example, we show that the joint approaches produce results that are feasible and reliable after comparing with the well data. Hence, these joint approaches have great potential to be the next-generation tools for reservoir description and prediction
3D wavefront attribute determination and conflicting dip processing
No full textThe knowledge of 3D wavefront attributes allows many important applications, such as stacking, 5D interpolation, 3D diffraction separation and imaging, and 3D wavefront tomography, just to name a few. For the determination of wavefront attributes, we use the common-reflection-surface (CRS) operator. We adopt a simultaneous search for the determination of wavefront attributes and combine it with conflicting dip processing. For the simultaneous search, we compare three heuristic global optimization algorithms such as particle swarm optimization (PSO), genetic algorithm (GA), and differential evolution (DE). For conflicting dip processing, a dip angle decomposition method for the probed sample is introduced and the simultaneous search is independently performed in specified dip ranges to individually obtain attributes and semblance for each range. Results for the laterally heterogeneous 3D SEG C3WA data indicate that DE has superior performance to determine the 3D wavefront attributes when compared with PSO, GA, and the conventional pragmatic approach because a higher semblance and an improved set of wavefront attributes are achieved. A comparison of the data-driven wavefront attributes obtained from the DE with the model-driven wavefront attributes computed by kinematic and dynamic ray tracing reveals the validity of the data-driven wavefront attributes. Combining the simultaneous search with conflicting dip processing for the 3D CRS stack further improved reflected energy and diffraction details when compared with results without simultaneous search and/or conflicting dip processing
Reliability of data-driven wavefront attributes in laterally heterogeneous media
No full text3D wavefront attributes play a major role in many processing steps, such as prestack data enhancement, diffraction separation, and wavefront tomography. For the determination of the 3D wavefront attributes, various stacking operators can be used by adopting semblance optimization. These operators are derived for laterally homogeneous media. In praxis, however, they are applied in real geologic environments with even strong lateral velocity variations such as salt structures. This leads to the question of the quality of the 3D wavefront attributes using these operators when determined in the presence of strong lateral velocity changes. We compared the 3D wavefront attributes determined by 3D common-reflection-surface (CRS) operator (called data-driven wavefront attributes) with the 3D wavefront attributes computed by 3D kinematic and dynamic ray tracing (called model-driven wavefront attributes). For the determination of the 3D CRS wavefront attributes, we have developed a global optimization scheme based on differential evolution. Reflection seismic data of the laterally heterogeneous 3D SEG C3WA salt model are considered, and the model-driven wavefront attributes are computed for a smoothed version of the 3D SEG salt model. The comparison reveals that the wavefront attributes for the normal-incidence-point ray indicate a very good match not only in areas of mild lateral velocity variation but even in regions with strong lateral velocity variations. Approximately 80%–90% of the total picks indicate the good match with a relative error of less than 10% when a semblance threshold of 0.1 is considered in the automatic picking process. This confirms the validity of the determined wavefront attributes even in the presence of strong lateral velocity changes. Using a higher semblance threshold in the automatic picking leads to fewer picks but with an even better match between model- and data-driven wavefront attributes
Zhonghua Jidu jiao hui he yi tang jian zhu zheng xin.
No full textCover title.; Special collection from London Missionary Society.; Also available in an electronic version via the Internet at http://nla.gov.au/nla.gen-vn442799.880-03 Xianggang Zhonghua Jidu jiao hui he yi tang jian zhu zheng xin lu.Story of Hop Yat (Union) Church, Hong Kong
5-D interpolation with wave-front attributes
No full textMost 5-D interpolation and regularization techniques reconstruct the missing data in the frequency domain by using mathematical transforms. An alternative type of interpolation methods uses wave-front attributes, that is, quantities with a specific physical meaning like the angle of emergence and wave-front curvatures. In these attributes structural information of subsurface features like dip and strike of a reflector are included. These wave-front attributes work on 5-D data space (e.g. common-midpoint coordinates in x and y, offset, azimuth and time), leading to a 5-D interpolation technique. Since the process is based on stacking next to the interpolation a pre-stack data enhancement is achieved, improving the signal-to-noise ratio (S/N) of interpolated and recorded traces. The wave-front attributes are determined in a data-driven fashion, for example, with the Common Reflection Surface (CRS method). As one of the wave-front-attribute-based interpolation techniques, the 3-D partial CRS method was proposed to enhance the quality of 3-D pre-stack data with low S/N. In the past work on 3-D partial stacks, two potential problems were still unsolved. For high-quality wave-front attributes, we suggest a global optimization strategy instead of the so far used pragmatic search approach. In previous works, the interpolation of 3-D data was performed along a specific azimuth which is acceptable for narrow azimuth acquisition but does not exploit the potential of wide-, rich- or full-azimuth acquisitions. The conventional 3-D partial CRS method is improved in this work and we call it as a wave-front-attribute-based 5-D interpolation (5-D WABI) as the two problems mentioned above are addressed. Data examples demonstrate the improved performance by the 5-D WABI method when compared with the conventional 3-D partial CRS approach. A comparison of the rank-reduction-based 5-D seismic interpolation technique with the proposed 5-DWABI method is given. The comparison reveals that there are significant advantages for steep dipping events using the 5-D WABI method when compared to the rank-reduction-based 5-D interpolation technique. Diffraction tails substantially benefit from this improved performance of the partial CRS stacking approach while the CPU time is comparable to the CPU time consumed by the rank-reduction-based method
Resolution enhancement of non-stationary seismic data using amplitude-frequency partition
No full textAs the Earth's inhomogeneous and viscoelastic properties, seismic signal attenuation we are trying to mitigate is a long-standing problem facing with high-resolution techniques. For addressing such a problem in the fields of time–frequency transform, Gabor transform methods such as atom-window method (AWM) and molecular window method (MWM) have been reported recently. However, we observed that these methods might be much better if we partition the non-stationary seismic data into adaptive stationary segments based on the amplitude and frequency information of the seismic signal. In this study, we present a new method called amplitude-frequency partition (AFP) to implement this process in the time–frequency domain. Cases of a synthetic and field seismic data indicated that the AFP method could partition the non-stationary seismic data into stationary segments approximately, and significantly, a high-resolution result would be achieved by combining the AFP method with conventional spectral-whitening method, which could be considered superior to previous resolution-enhancement methods like time-variant spectral whitening method, the AWM and the MWM as well. This AFP method presented in this study would be an effective resolution-enhancement tool for the non-stationary seismic data in the fields of an adaptive time–frequency transform
杏元和番 = Xingyuan he fan
No full textOn double leaves, oriental styleCover titleHarry Simon Collection[成都] : 和記書莊印, [19--?]At head of title : 重台 = Chong taiRunning title : 杏元和番 = Xingyuan he fa
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