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Least-squares reverse-time migration for reflectivity imaging

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Science China Earth Sciences 2015年第11期58卷 1982-1992页

作者： yao gang WU Di Department of Earth Science and Engineering Imperial College London The Unconventional Natural Gas Institute China University of Petroleum (Beijing)

A least-squares reverse-time migration scheme is presented for reflectivity imaging. Based on an accurate reflection modeling formula, this scheme produces amplitude-preserved stacked reflectivity images with zero phase. Spatial preconditioning, weighting and the Barzilai-Borwein method are applied to speed up the convergence of the least-squares inversion. In addition, this scheme compensates the effect of ghost waves to broaden the bandwidth of the reflectivity images. Furthermore, roughness penalty constraint is used to regularize the inversion, which in turn stabilizes inversion and removes high-wavenumber artifacts and mitigates spatial aliasing. The examples of synthetic and field datasets demonstrate the scheme can generate zerophase reflectivity images with broader bandwidth, higher resolution, fewer artifacts and more reliable amplitudes than conventional reverse-time migration.

关键词： adjoint migration least-squares reverse-time migration cross-correlation imaging condition deconvolution imagingcondition deghost

Reflection full waveform inversion

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Science China Earth Sciences 2017年第10期60卷 1783-1794页

作者： yao gang WU Di Department of Earth Science and Engineering Imperial College London The Unconventional Natural Gas Institute China University of Petroleum

Because of the combination of optimization algorithms and full wave equations, full-waveform inversion(FWI) has become the frontier of the study of seismic exploration and is gradually becoming one of the essential tools for obtaining the Earth interior information. However, the application of conventional FWI to pure reflection data in the absence of a highly accurate starting velocity model is difficult. Compared to other types of seismic waves, reflections carry the information of the deep part of the subsurface. Reflection FWI, therefore, is able to improve the accuracy of imaging the Earth interior further. Here, we demonstrate a means of achieving this successfully by interleaving least-squares RTM with a version of reflection FWI in which the tomographic gradient that is required to update the background macro-model is separated from the reflectivity gradient using the Born approximation during forward modeling. This provides a good update to the macro-model. This approach is then followed by conventional FWI to obtain a final high-fidelity high-resolution result from a poor starting model using only reflection *** analysis reveals the high-resolution result is achieved due to a deconvolution imaging condition implicitly used by FWI.

关键词： Full-waveform inversion Reflection full-waveform inversion Least-squares reverse-time migration Tomographic gradient Reflectivity gradient Deconvolution imaging condition

Creating animal models, why not use the Chinese tree shrew ( Tupaia belangeri chinensis)？

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Zoological Research 2017年第3期38卷 118-126页

作者： Yong-gang yao Key Laboratory of Animal Models and Human Disease Mechanisms Kunming Institute of Zoology Chinese Academy of SciencesKunming Yunnan 650223 China Kunming Primate Research Center of the Chinese Academy of Sciences Kunming Institute of Zoology Chinese Academy of SciencesKunming Yunnan 650223 China

The Chinese tree shrew （Tupaia belangeri chinensis） a squirrel-like and rat-sized mammal, has a wide distribution in Southeast Asia, South and Southwest China and has many unique characteristics that make it suitable for use as an experimental animal. There have been many studies using the tree shrew （Tupaia belangeri） aimed at increasing our understanding of fundamental biological mechanisms and for the modeling of human diseases and therapeutic responses. The recent release of a publicly available annotated genome sequence of the Chinese tree shrew and its genome database （***） has offered a solid base from which it is possible to elucidate the basic biological properties and create animal models using this species. The extensive characterization of key factors and signaling pathways in the immune and nervous systems has shown that tree shrews possess both conserved and unique features relative to primates. Hitherto, the tree shrew has been successfully used to create animal models for myopia, depression, breast cancer, alcohol-induced or non-alcoholic fatty liver diseases, herpes simplex virus type 1 （HSV-1） and hepatitis C virus （HCV） infections, to name a few. The recent successful genetic manipulation of the tree shrew has opened a new avenue for the wider usage of this animal in biomedical research. In this opinion paper, I attempt to summarize the recent research advances that have used the Chinese tree shrew, with a focus on the new knowledge obtained by using the biological properties identified using the tree shrew genome, a proposal for the genome-based approach for creating animal models, and the genetic manipulation of the tree shrew. With more studies using this species and the application of cutting-edge gene editing techniques, the tree shrew will continue to be under the spot light as a viable animal model for investigating the basis of many different human diseases.

关键词： Chinese tree shrew Genome biology Animal model Gene editing Innate immunity

Synthesis of Petri net supervisors enforcing general constraints

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第4期7卷 623-628页

作者： ZHANG yao-yao YAN gang-feng School of Electrical Engineering Zhejiang University Hangzhou 310027 China

This paper deals with the synthesis of Petri net supervisor enforcing the more expressive constraints including marking terms, firing vector terms and Parikh vector terms. The method is developed to handle uncontrollable and unobservable transitions existing in the constraints. The “greater-than or equal” general constraints can also be transformed into “less-than or equal” Parikh constraints. An example is analyzed to show how the problem is solved. General constraint is first transformed into Parikh vector constraints, and Matrix-Transformation is proposed to obtain the admissible constraints without uncontrollable and unobservable transitions. Then the supervisor can be constructed based on constraints only consisting of Parikh vector terms. The method is proved to be more concise and effective than the method presented by Iordache and Moody especially when applied to large scale systems.

关键词： Petri net Supervisor control Parikh vector Uncontrollable Unobservable

Pursuing innovation in a new era

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ZOOLOGICAL RESEARCH 2024年第6期45卷 1232-1234页

作者： yao, Yong-gang Shi, Peng Chinese Acad Sci Kunming Inst Zool Kunming 650223 Yunnan Peoples R China

This year marks a significant milestone as we celebrate the75th anniversary of our nation,alongside the 65th anniversary of the Kunming Institute of Zoology(KIZ) and the 75^(th) anniversary of the Chinese Academy of Sciences(CAS).This juncture provides an opportunity to reflect on our progress over the past five years and strategically enhance our culture of innovation,while pursuing new aspirations(yao & Shen,2019).It is a critical moment to advance innovation and take decisive steps toward leadership in this new era.

关键词： steps anniversary strategic

From our roots, we grow

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Zoological Research 2019年第6期40卷 471-475页

作者： Yong-gang yao Hua Shen Kunming Institute of Zoology Chinese Academy of SciencesKunming Yunnan 650223China

Located at the head of the Indo-Burma biodiversity hotspot,the Kunming Institute of Zoology (KIZ), Chinese Academy of Sciences (CAS), serves as China’s main center for research into the diverse animal and ecological ... 详细信息

关键词： Kunming Institute of Zoology ecological resources

Magnesium effects on behavior and substance P mRNA expression in the midbrain of a rat migraine model

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Neural Regeneration Research 2009年第11期4卷 912-917页

作者： Tingmin Yu gang yao Liping Zhang Department of Life Science Northeast Normal University Changchun 130024 Jilin Province China Department of Neurology Second Hospital of Jilin University Changchun 130041 Jilin Province China

BACKGROUND： Substance P participates in pain transmission and modulation, suggesting a close association with migraine headaches. The clinical application of magnesium has been effective in treating migraines, and the action mechanisms underlying migraines correlate with substance P expression. OBJECTIVE： To analyze different magnesium doses on behavior and substance P mRNA expression in the midbrain of a rat migraine model, and to determine the action pathway of migraine treatment using magnesium. DESIGN, TIME AND SETTING： A completely randomized, controlled, animal experiment was performed at the Experimental Animal Center and Central Laboratory in the Second Hospital of Jilin University between 2007 and 2008. MATERIALS： Magnesium sulfate （25%） was supplied by Tianjin Pharmaceutical Jiaozuo, China. Nitroglycerin was provided by Shanxi Kangbao Biological, China. Substance P primer sequence was synthesized by TaKaRa Biotechnology （Dalian）, China. METHODS： A total of 36 healthy, adult, Wistar rats were randomly assigned to 6 groups： control, migraine, low- and high-dose magnesium sulfate treated, and low- and high-dose magnesium sulfate control, with 6 rats in each group. Migraines were induced by subcutaneous injection of 10 mg/kg nitroglycerin in the migraine and low- and high-dose magnesium sulfate treated groups, and 2 mL/kg physiological saline was administered to rats in the control and low- and high-dose of magnesium sulfate control groups. Five minutes following administration, rats in low-dose groups were intraperitoneally injected with 100 mg/kg magnesium sulfate, while those in high-dose groups were injected with 300 mg/kg magnesium sulfate. No interventions were administered to the control and migraine groups. MAIN OUTCOME MEASURES： At 2 hours after nitroglycerin injection, substance P mRNA expression in the rat midbrain was measured by real-time quantitative polymerase chain reaction. At 60-90 minutes after nitroglycerin injection, behavioral changes of

关键词： substance P migraine magnesium midbrain real-time quantitative polymerase chain reaction: rat

A review on reflection-waveform inversion

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Petroleum Science 2020年第2期17卷 334-351页

作者： gang yao Di Wu Shang-Xu Wang Unconventional Petroleum Research Institute State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Beijing 102249China College of Geophysics State Key Laboratory of Petroleum Resources and ProspectingChina University of Petroleum(Beijing)Beijing 102249China

Full-waveform inversion(FWI)utilizes optimization methods to recover an optimal Earth model to best fit the observed seismic record in a sense of a predefined *** FWI combines mathematic inversion and full-wave equations,it has been recognized as one of the key methods for seismic data imaging and Earth model building in the fields of global/regional and exploration ***,conventional FWI fixes background velocity mainly relying on refraction and turning waves that are commonly rich in large *** contrast,reflections in the short offsets mainly contribute to the reconstruction of the high-resolution *** by acquisition geometries,refractions and turning waves in the record usually have limited penetration depth,which may not reach oil/gas ***,reflections in the record are the only source that carries the information of these ***,it is meaningful to develop reflection-waveform inversion(RWI)that utilizes reflections to recover background velocity including the deep part of the *** review paper includes:analyzing the weaknesses of FWI when inverting reflections;overviewing the principles of RWI,including separation of the tomography and migration components,the objective functions,constraints;summarizing the current status of the technique of RWI;outlooking the future of RWI.

关键词： Full-waveform inversion Reflection-waveform inversion Tomographic component Migration component Travel time-based objective function Waveform-based objective function Constraint

Zoological Research shines in the East

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Zoological Research 2022年第1期43卷 1-2页

作者： Yong-gang yao Yun Zhang Institute of Zoology Chinese Academy of SciencesKunmingYunnan 650223China Kunming Institute of Zoology Chinese Academy of SciencesKunming Yunnan 650223China

With the long-term support of every friend and contributor,Zoological Research(ZR)has continued to move forward over the past year,with impressive ***,ZR attained an impact factor of 4.56(JCR Q1)and CiteScore of 4.6 in mid-2021,thus ranking in the top five of the 175 SCI journals within the Zoology *** November 2021,our Citescore reached 5.6,and we expect a higher impact factor in 2022 than in *** we are not driven by chasing these scores,the increase in these metrics does reflect an elevation in the quality of submissions and publications,as well as the march towards our original aspiration when launching this journal(yao et al.,2019).The current areas of focus of ZR(i.e.,primate and animal models;animal diversity and evolution;conservation&utilization of animal resources)are not only tightly connected to our host-the Kunming Institute of Zoology,which has grown and evolved into“a comprehensive research institution renowned for its remarkable achievements in evolutionary mechanisms of animal biodiversity,animal resources protection,and sustainable utilization”(yao&Shen,2019)-but also represent the very frontiers of zoology.

关键词： frontier journal utilization