关键词： 泥石流   点云处理   地貌形态   摄影测量  

摘要： 针对重庆綦江~万盛高速公路边坡在强降雨条件下形成的坡面泥石流,采用消费级无人机航拍生成坡面泥石流点云数据。采用C++编程语言对点云数据进行切片、投影、排序、深度计算、体积计算等操作,提出了基于点云切片提取泥石流各断面侵蚀-堆积极值点平面/剖面分布、侵蚀-堆积体积等地貌特征的方法。结合该研究区进行分析可知,坡面泥石流内部存在侵蚀-堆积优势区域;该坡面泥石流侵蚀-堆积体积与平均侵蚀-堆积深度重合度高,与坡面泥石流宽度大、侵蚀深度浅的特点有关。基于点云数据处理的坡面泥石流形态特征提取方法可从不同角度对地貌特征进行分析,对坡面泥石流侵蚀-堆积关系与其产流-汇流-堆积演化过程研究具有积极意义。

ISBN: (纸本)9787030697097

ISBN: (纸本)9787115571861

关键词： Data processing   distributed systems  

摘要： Optimizing scheduling and communication of distributed data processing for resource and data characteristics is crucial for achieving high performance. Existing approaches to such optimizations largely fall into two categories. First, distributed runtimes provide low-level policy interfaces to apply the optimizations, but do not ensure the maintenance of correct application semantics and thus often require significant effort to use. Second, policy interfaces that extend a high-level application programming model ensure correctness, but do not provide sufficient fine control. We describe Apache Nemo, an optimization framework for distributed dataflow processing that provides fine control for high performance and also ensures correctness for ease of use. We combine several techniques to achieve this, including an intermediate representation of dataflow, compiler optimization passes, and runtime extensions. Our evaluation results show that Nemo enables composable and reusable optimizations that bring performance improvements on par with existing specialized runtimes tailored for a specific deployment scenario. Apache Nemo is open-sourced at https://*** as an Apache incubator project.

关键词： LIBS   Quantification   Uncertainty reduction   Plasma modulation  

摘要： Laser-induced breakdown spectroscopy (LIBS) is regarded as the future superstar for chemical analysis, but the relatively high measurement uncertainty and error remain the persistent challenges for its technological development as well as wide applications. In the present work, mechanisms of measurement uncertainty generation and basic principle of signal uncertainty and matrix effects impacting quantification performance were explained. Furthermore, methods for raw signal improvement including sample preparation, system optimization, and especially plasma modulation, which modulates the laser-induced plasma evolution process for higher signal repeatability and signal-to-noise ratio, were reviewed and discussed. Different LIBS mathematical quantification methods including calibration-free methods and calibration methods, which were classified into physical-principle based calibration model, data-driven based calibration model, and hybrid model, were discussed and compared. Overall, a framework of quantification improvement strategy including key steps and main way-out was summarized and recommended for LIBS future development. (C) 2021 Elsevier B.V. All rights reserved.

关键词： X-ray emission spectroscopy   Chemical speciation   Principal component analysis   Perovskites  

摘要： Wet chemical method was applied with the intention of obtaining Lu1-xSrxFe0.5Cr0.5O3 (0 < x < 1) perovskites in polycrystalline form. A systematic study of the crystal structure of the main perovskite phase obtained as well as a characterization of impurities was performed by X-ray techniques: powder diffraction (PXRD), high resolution emission spectroscopy (HR-XES), and photoelectron spectrometry (XPS). The PXRD data of Lu1-xSrxFe0.5Cr0.5O3 (0 < x < 1) were refined using Pbnm orthorhombic unit cell for the perovskite structure. Only samples with x = 0 and x = 0.1 resulted pure;as the amount of Sr increases, it is segregated as impurities, first as SrCrO4 and then as SrFe12O19. The mean oxidation state of Cr in the analyzed samples was obtained from HR-XES by quantifying spectral changes in the Cr-K beta" and Cr-K beta 2,5 regions by different methodologies: statistical parameters and multivariate methods. The results were compared with the ones obtained by PXRD and XPS. With the last technique Cr6+ ionic concentrations were obtained through the spectral analysis in the region Cr2p3/2-580eV. Similar Cr6+ ionic compositions were obtained using the three X-ray techniques.

ISBN: (纸本)9787518349005

关键词： 4D-STEM   first moment imaging   In2Se3   phase retrieval   ptychography   SrTiO3  

摘要： A reformulated implementation of single-sideband ptychography enables analysis and display of live detector data streams in 4D scanning transmission electron microscopy (STEM) using the LiberTEM open-source platform. This is combined with live first moment and further virtual STEM detector analysis. Processing of both real experimental and simulated data shows the characteristics of this method when data are processed progressively, as opposed to the usual offline processing of a complete data set. In particular, the single-sideband method is compared with other techniques such as the enhanced ptychographic engine in order to ascertain its capability for structural imaging at increased specimen thickness. Qualitatively interpretable live results are obtained also if the sample is moved, or magnification is changed during the analysis. This allows live optimization of instrument as well as specimen parameters during the analysis. The methodology is especially expected to improve contrast- and dose-efficient in situ imaging of weakly scattering specimens, where fast live feedback during the experiment is required.

关键词： Apache Storm   RDMA   InfiniBand   Stream-processing framework   Cloud computing   Communication optimization  

摘要： Apache Storm is a scalable fault-tolerant distributed real time stream-processing framework widely used in big data applications. For distributed data-sensitive applications, low-latency, high-throughput communication modules have a critical impact on overall system performance. Apache Storm currently uses Netty as its communication component, an asynchronous server/client framework based on TCP/IP protocol stack. The TCP/IP protocol stack has inherent performance flaws due to frequent memory copying and context switching. The Netty component not only limits the performance of the Storm but also increases the CPU load in the IPoIB (IP over InfiniBand) communication mode. In this paper, we introduce two new implementations for Apache Storm communication components with the help of RDMA technology. The performance evaluation on Mellanox QDR Cards (40 Gbps) shows that our implementations can achieve speedup up to 5x compared with IPoIB and 10 x with Gigabit Ethernet. Our implementations also significantly reduce the CPU load and increase the throughput of the system.

关键词： BRCT domain   GST pull-down assay   Mass spectrometry   HADDOCK   PDB   Dictyostelium discoideum  

摘要： Poly (ADP-ribose) polymerase-1 (PARP-1) is a multifunctional protein that is associated with various biological processes like chromatin remodeling, DNA damage, cell death etc. In Dictyostelium discoideum, PARP-1 has also been implicated in cellular differentiation and development. However, its interacting proteins during multicellular development are not yet explored. Hence, the present study aims to identify PARP-1 interacting proteins during multicellular development of D. discoideum. BRCA1 C-terminus (BRCT) domain of PARP-1, which is mainly involved in protein-protein interactions was cloned in pGEX4T1 vector and developmental interactome of PARP-1 were analyzed by affinity purification-mass spectrometry. These interactions were further confirmed by in-silico protein-protein docking analysis, which led to identification of the proteins that show high affinity for BRCT domain. Initially, the protein structures were modeled on SWISS MODEL and PHYRE2 servers, refined by 3D-refine and validated by PROCHECK. Further, interaction sites of BRCT and the conserved regions in all interacting proteins were predicted using cons-PPISP and ConSurf, respectively. Finally, protein-protein docking analysis was done by HADDOCK. Our results identified 19 possible BRCT interacting proteins during D. discoideum development. Furthermore, interacting residues involved in the interactions and functional regions were explored. This is the first report where PARP-1's developmental interactome in D. discoideum is well established. The current findings demonstrate PARP-1's developmental interactome in D. discoideum and provide the groundwork to understand its regulated functions in developmental biology which would undoubtedly extend our perception towards developmental diseases in higher complex organisms and their treatment.