关键词： GAMIT   数据处理   IGS站   标准均方根   基线重复率  

摘要： 随着高精度GNSS在地学中的应用越来越广泛,如何提高GNSS数据处理精度成为一个热点问题。IGS站的选取对GNSS数据处理的精度起着重要的作用。论文以GNSS数据处理软件GAMIT进行数据处理为例,从IGS站选取的几何意义和统计意义,研究其对GNSS数据处理精度的影响。通过比较和分析,说明合理先取IGS站点能够有效提高基线解算的精度,并对合理选取IGS站点的方法提出建议。

关键词： forward model   Abel integral   radio occultation data processing   interpolation of a forward model   evaluation of forward model   sensitivity of forward model  

摘要： In radio occultation (RO) data processing and data assimilation, the forward model (FM) is used to calculate bending angle (BA) from refractivity (N). The accuracy and precision of forward modeled BA are affected by refractivity profiles and FM methods, including Abel integral algorithms (direct, exp, exp_T, linear) and methods of interpolating refractivity during integral (log-cubic spline and log-linear). Experiment 1 compares these forward model methods by comparing the difference and relative difference (RD) of the experimental value (forward modeled ECMWF analysis) and the true value (BA of FY3D RO data). Results suggested that the exp with log-cubic spline (log-cubic) interpolation is the most accurate FM because it has better integral accuracy (less than 2%) to inputs, especially when the input is lower than an order of magnitude of 1 x 10(-2) (that is, above 60 km). By contrast, the direct induced a 10% error, and the improvement of exp T to exp is limited. Experiment 2 simulated the exact errors of an FM (exp) based on inputs on different vertical resolutions. The inputs are refractivity profiles on model levels of three widely used analyses, including ECMWF 4Dvar analysis, final operational global analysis data (FNL), and ERA5. Results demonstrated that based on exp and log-cubic interpolation, BA on model level of ECMWF 4Dvar has the highest accuracy, whose RD is 0.5% between 0-35 km, 4% between 35-58 km, and 1.8% between 58-80 km. By contrast, the other two analyses have low accuracy. This paper paves the way to better understanding the FM, and simulation errors on model levels of three analyses can be a helpful FM error reference.

关键词： Combination index   Dual antiplatelet therapy   Platelet inhibitors   Regression   Synergism  

摘要： Introduction: The combination index (CI), a common quantitative indicator of the degree of synergy/antagonism, may be determined using different regression methods. However, any analysis with constraints has the potential for underestimating the combined effect of multiple drugs. Objectives: This in vitro study describes the combined effects of selected platelet antagonists on ADP-induced platelet activation in different regression models. Methods: The inhibitory effects of P2Y(12) receptor antagonists in combination with P2Y(1) receptor antagonists (i.e. cangrelor with MRS 2279, prasugrel metabolite with MRS 2179 and PSB 0739 with MRS 2179) were characterized with the aid of three software packages: CompuSyn (for linear regression with constraints), CISNE (for non-linear regression with constraints) and GraphPad Prism (for non-linear regression without constraints). The synergism between P2Y(12) and P2Y(1) inhibitors was quantified by CI and synergy area. Results: MRS 2279 and MRS 2179 were found to act synergistically with selected P2Y(12) receptor antagonists to potentiate their antiplatelet effect. The models of regression with constraints, linear regression in particular, demonstrated a worse fit for experimental data than non-linear regression without constraints;this resulted in an incorrect estimation of the combined effects of two antiplatelet drugs, i.e., underestimating the CI and over-estimating the synergy area. Also, the synergy area was found to better reflect the differences among models than the CI. Conclusions: These findings suggest that non-linear regression without constraints offers more precise quantitative determination of combined effects between two drugs compared to the regression models with constraints.

关键词： Strong data processing inequality (SDPI)   contraction coefficient   f-divergence  

摘要： For any channel P-Y vertical bar X the strong data processing constant is defined as the smallest number eta(KL) is an element of [0,1] such that I(U;Y) <= eta I-KL(U;X) holds for any Markov chain U - X - Y. It is shown that the value of eta(KL) is given by that of the best binary-input subchannel of P-Y vertical bar X. The same result holds for any f-divergence, verifying a conjecture of Cohen, Kemperman and Zbaganu (1998).

关键词： 生态环境   数据处理  

ISBN: (纸本)9787030699732

摘要： 当今生态学已经发展到大科学、大数据、大理论时代，生态大数据的集成分析与信息挖掘逐渐成为地球系统科学研究的重要手段。

关键词： Allosteric regulation   Enzyme evolution   Post-translational regulation   Redox regulation   Subfunctionalization   Nucleotide-sugar synthesis  

摘要： Key message This review outlines research performed in the last two decades on the structural, kinetic, regulatory and evolutionary aspects of ADP-glucose pyrophosphorylase, the regulatory enzyme for starch biosynthesis. ADP-glucose pyrophosphorylase (ADP-Glc PPase) catalyzes the first committed step in the pathway of glycogen and starch synthesis in bacteria and plants, respectively. Plant ADP-Glc PPase is a heterotetramer allosterically regulated by metabolites and post-translational modifications. In this review, we focus on the three-dimensional structure of the plant enzyme, the amino acids that bind the regulatory molecules, and the regions involved in transmitting the allosteric signal to the catalytic site. We provide a model for the evolution of the small and large subunits, which produce heterotetramers with distinct catalytic and regulatory properties. Additionally, we review the various post-translational modifications observed in ADP-Glc PPases from different species and tissues. Finally, we discuss the subcellular localization of the enzyme found in grain endosperm from grasses, such as maize and rice. Overall, this work brings together research performed in the last two decades to better understand the multiple mechanisms involved in the regulation of ADP-Glc PPase. The rational modification of this enzyme could improve the yield and resilience of economically important crops, which is particularly important in the current scenario of climate change and food shortage.

ISBN: (纸本)9787576500882

关键词： digital signal processing   analysis of rheographic signals   base impedance compensation   rheogram characteristic points   impedance plethysmography   avanced computing methods  

摘要： In this paper we are introducing innovative solutions applied in impedance plethysmography concerning improvement of the rheagraph characteristics and the efficiency increase of the developing rheograms using computer methods. The described methods have been developed in order to ensure the stability of parameters and to extend the functionality of the rheographic system based on digital signal processing, which applies to the compensation of the base resistance with a digital potentiometer, digital synthesis of quadrature excitation signals and the performance of digital synchronous detection. The emphasis was put on methods for determination of hemodynamic parameters by computer processing of the rheograms. As a result-three methods for respiratory artifacts elimination have been proposed: based on the discrete cosine transform, the discrete wavelet transform and the approximation of the zero line with spline functions. Additionally, computer methods for physiological indicators determination, including those based on wavelet decomposition, were also proposed and described in this paper. The efficiency of various rheogram compression algorithms was tested, evaluated and presented in this work.

关键词： spatio-temporal sensing data   spatio-temporal data processing   spatio-temporal index   polygon range query algorithm   k nearest neighbor query algorithm   query optimization   SpatialHadoop  

摘要： The unprecedented development of Internet of Things (IoT) technology produces humongous amounts of spatio-temporal sensing data with various geometry types. However, processing such datasets is often challenging due to high-dimensional sensor data geometry characteristics, complex anomalistic spatial regions, unique query patterns, and so on. Timely and efficient spatio-temporal querying significantly improves the accuracy and intelligence of processing sensing data. Most existing query algorithms show their lack of supporting spatio-temporal queries and irregular spatial areas. In this paper, we propose two spatio-temporal query optimization algorithms based on SpatialHadoop to improve the efficiency of query spatio-temporal sensing data: (1) spatio-temporal polygon range query (STPRQ), which aims to find all records from a polygonal location in a time interval;(2) spatio-temporal k nearest neighbors query (STkNNQ), which directly searches the query point's k closest neighbors. To optimize the STkNNQ algorithm, we further propose an adaptive iterative range optimization algorithm (AIRO), which can optimize the iterative range of the algorithm according to the query time range and avoid querying irrelevant data partitions. Finally, extensive experiments based on trajectory datasets demonstrate that our proposed query algorithms can significantly improve query performance over baseline algorithms and shorten response time by 81% and 35.6%, respectively.

关键词： 视频系统   数据采集   数据处理  

ISBN: (纸本)9787563564446

摘要： 本书主要研究了面向智慧旅游的视频数据智能处理与挖掘相关技术及应用，以提高旅游景区视频大数据中异常事件检测和识别的精度、鲁棒性、实时性等性能为目的，从而实现对旅游突发事件及时预测和预警，保障旅游安全。本书首先研究了视频大数据的去噪技术，重点研究了基于残差卷积神经网络的视频去噪算法；然后研究了视频大数据的超分辨率重建技术，重点研究了综合深度学习、半耦合字典学习和时空非局部相似性特征的视频超分辨率重建算法；其次研究了旅游景区视频的显著性时空特征提取算法；然后在此基础上研究了旅游景区视频大数据中的异常事件检测和识别技术，重点研究了基于稀疏组合学习的旅游景区视频异常事件检测算法，以及基于时空感知深度网络的旅游景区视频异常事件识别算法。最后设计并实现了面向视频大数据的旅游突发事件监测系统。