Variation analysis of ultimate pullout capacity of shallow horizontal strip anchor plate with 2-layer overlying soil based on nonlinear M-C failure criterion

Based on the nonlinear Mohr-Coulomb failure criterion and an associated flow rule,a kinematic admissible velocity field of failure mechanism of the 2-layer soil above a shallow horizontal strip anchor plate is constructed.The ultimate pull-out force and its corresponding failure mechanism through the upper bound limit analysis according to a variation principle are deduced.When the 2-layer overlying soil is degraded into single-layer soil,the model of ultimate pullout force could also be degraded into the model of single-layer soil.And the comparison between results of single-layer soil variation method and those calculated by rigid limit analysis method proves the correctness of our method.Based on that,the influence of changes of geotechnical parameters on ultimate pullout forces and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are analyzed.The results show that the ultimate pull-out force and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are affected by the nonlinear geotechnical parameters greatly.Thus,it is very important to obtain the accurate geotechnical parameters of 2-layer soil for the evaluation of the ultimate pullout capacity of the anchor plate.

Peak of Electron Density in F2-Layer Parameters Variability at Quiet Days on Solar Minimum

This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried out from the two nearest days (previous and following of quietest day). The study uses International Reference Ionosphere (IRI) for ionosphere modeling. The located station is Ouagadougou, in West Africa. Solar minimum of phase 22 is considered in this study. Using three core principles of ionosphere modeling under IRI running conditions, the study enables to carry out Peak of electron density in F2-layer values during the quietest days of the characteristic months for the four different seasons. These parameters are compared to those of the previous and the following of the quietest days (the day before and following each quietest selected day) at the same hour. The knowledge of NmF2 values at the quietest days and at the two nearest days enables to calculate the relative error that can be made on this parameter. This calculation highlights insignificant relative errors. This means that NmF2 values at the two nearest days of each quietest day on solar minimum can be used for simulating the quietest days’ behavior. NmF2 values obtained by running IRI model have good correlation with those carried out by Thermosphere-Ionosphere-Electrodynamics-General Circulation Model (TIEGCM).

Electron Bulk Surface Density Effect on Critical Frequency in the F2-Layer

Ionosphere layer is the atmosphere region which reflects radio waves for telecommunication. The density in particles in this layer influences the quality of communication. This study deals with the effects of Total Electron Contents (TEC) on the critical frequency of radio waves in the F2-layer. Total Electron Contents parameter symbolizes electron bulk surface density in ionosphere layer. Above critical frequency value in F2 layer (foF2), radio waves pass through ionosphere. The knowledge of this value enables to calibrate transmission frequencies. In this study, we consider TEC effects on foF2 under quiet time conditions during the maximum and the minimum of solar cycle 22, at Ouagadougou station, in West Africa. The study also considers the effects of seasons and the hourly variability of TEC and foF2. This work shows winter anomaly on foF2 and TEC on minimum and maximum of solar cycle phase respectively. Running International Reference Ionosphere (IRI) model enables to carry out the effects of TEC on foF2 by use of their monthly average values. This leads to a new approach to calibrate radio transmitters.

An Empirical Study of Word Class Labeling of Total Reduplication Lex⁃ emes in New Century Chinese-English Dictionary ( 2nd edition)

the widely discussed study of word class categorization has a long history of more than 2000 years,which is known as the study of the“God Particles”in language.As a typical analytic language,Modern Chinese,due to its lack of morphological changes,is challenged by a thorny problem of word classes especially when it comes to the criteria for word class identification and the treat⁃ment of multiple class membership.As such,all the controversies eventually give rise to some contradiction and confusion in word class labeling in Modern Chinese and Chinese-English dictionaries.As an important grammatical means in Chinese and the focus of lexicology and rhetorics,total reduplication lexemes serve as an essential part of Chinese-English dictionaries with complex and diverse word classes.Guided by the Two-level Word Class Categorization Theory,this thesis focuses on the word class labeling of total reduplication lexemes in New Century Chinese-English Dictionary(2nd edition)backed by large-scale balanced Modern Chi⁃nese corpora.With an innovative theoretical perspective,this study not only contributes to the word class labeling of total reduplica⁃tion lexemes and even sheds light on the compilation of Chinese-English dictionaries,but also drives the study of Modern Chinese word classes in the long term.

基于L_(1/2)正则化的超分辨率图像重建算法

为提高图像重建质量,研究超分辨率图像重建技术与稀疏表示理论,提出一种基于L1/2正则化的超分辨率图像重建算法。将L1/2正则化理论运用到字典学习中,利用学习得到的字典重建高分辨率图像。实验结果表明,该算法的图像重建效果优于基于L1正则化的超分辨率图像重建算法。

基于l_(1/2)正则化的稀疏表示目标跟踪算法的研究

近年来目标的稀疏表示已经广泛应用到视频跟踪中。文中提出了一种基于局部稀疏表示的鲁棒目标跟踪算法,目标的表示将局部信息考虑在内,并且做出了遮挡处理。为了在新的帧中跟踪到目标,每一个候选目标通过在线构建的过完备字典以及模板解l1/2最小化问题稀疏表示。文中用l1/2规范最小化来代替l0,而不是用l1规范最小化,通过解l1/2最小化问题,可以找到比解l1最小化更稀疏、更精确的解。此外,l1/2比l0更容易求解。目标稀疏表示后,通过在线学习的分类器将目标区分出来。实验结果表明,与现有的一些算法相比,该算法稳定性好,性能更优越。

Self-Adapting Routing for Two-Layered Satellite Networks

The rapid advancement of communication and satellite technology drives broadband satellite networks to carry different traffic loads.However,traffic class routing of satellite cannot be provided by the existing 2-layerd satellite networks.In this paper,a 2-layered satellite network composed of low-Earth orbit and medium-Earth orbit satellite networks is presented,and a novel Self-adapting Routing Protocol(SRP)is developed.This scheme aims to adopt self-adapting routing algorithm to support different traffic classes.Meanwhile,the path discovery processing is invoked independently for each individual origin/destination pair.Simulation results are provided to evaluate the performance of the new scheme in terms of end-to-end delay,normalized data throughput,delay jitter and delivery ratio.

基于L_(1/2)自适应稀疏正则化的图像重建算法

为了解决图像超分辨率重建过程中出现的问题,结合图像的稀疏表示,增加控制邻近块兼容性的约束,建立具有邻近块兼容性约束的L1/2稀疏正则化模型.采用加权L2范式代替Lp(0<p<1)范式,对迭代加权最小二乘法进行转化,提出一种自适应正则化参数选取的算法.通过拼接字典的方法,训练出重要的特征并优化了重建图像的质量.实验结果表明,该重建方法在去噪和保留边缘信息方面具有较好的效果,重建的高分辨率图像在视觉上具有清晰锐利的特点,而且在峰值信噪比和结构相似度两项指标上都优于传统的重建方法.

基于Web应用的MVC架构实现——AWDF

Agile Web Development Framework(AWDF)开发框架是作者提出的一种新型的Web开发框架,它基于MVC模型2,用于Web应用的开发。通过与struts的比较提出了AWDF的优势所在,并对AWDF的设计思想、框架模式、各个组成部分的定义功能及责任作了详细的描述。此构架的优势在于与其它框架相比,它的简单易用使得降低系统的复杂度和系统的开发成本成为可能;并且AWDF框架采用可复用的数据验证的机制来提高系统的可复用性,从而使得在大型系统的开发中使用此构架成为可能。

基于降维稀疏重构的相干信源二维DOA估计方法

直接将压缩感知(compressed sensing,CS)思想应用到相干信源二维波达方向(direction of arrival,DOA)估计中会带来高计算复杂度的问题。为了解决这一问题,提出了一种基于降维稀疏重构的二维DOA估计方法,该方法利用特殊阵列结构将二维冗余字典构建问题转化为一维冗余字典的构建,同时提出了一种基于子字典空间谱重构的配对算法,从而在极大降低算法计算复杂度的同时,提高了配对成功概率。仿真结果表明,该方法对相干信源具有接近于克拉美罗下界(Cramér-Rao lower bound,CRLB)的估计性能,即使是在低信噪比、少快拍数和小角度间隔的情况下,仍有良好的估计性能。

一次全面深入的修订——《汉语大词典》第二版第一册管窥

文章指出《汉语大词典》的修订是一项难度很大、需要付出艰辛劳动的工作;通过与旧版的比较,认为第二版的修订目标和实际工作远远超出预期,是一次全面而深入的修订;文中扼要介绍了第二版第一册取得的成绩和闪烁的亮点,也指出第一册尚存在的不足,并对今后的工作提出了两点供参考的建议。

支持非第一范式的DBMS中DD的设计和实现

NFMDB数据库管理系统是在 RDBMS的基础上扩充而成的 ,它支持非第一范式 NF2 (Nonfirst normal form)及多媒体数据类型。首先 ,分析了集中式和分离式字典系统的特点 ,并阐述了主动 DD和被动 DD的区别 ;其次 ,讨论了 NFMDB系统为处理 NF2问题而引入的关系字典、属性字典等字典的构造 ,并给出了部分结构描述 ;然后 ,用 create语句描述了一个关于 NF2 存储模式实例 ,同时以 select语句为例讨论了用关系字典和属性字典为基础转换多维 NF2 问题为平滑关系的算法 ,所有这些操作均在关系字典和属性字典中给出了相应的存储描述 ;最后 ,探讨了以关系方式存储 DD的优点以及 DD与 DBMS的关系。由此得出以扩充 DD系统为基础处理 NF2 问题是可行的。

多模态大数据语境下科技术语翻译标准分析——以新冠肺炎和新冠病毒术语翻译为例

科技术语翻译在全球贸易、科技传播中起着举足轻重的作用,但还存在不准确、不规范和不一致等现象,例如在线词典、机器翻译引擎、在线百科等提供的新冠肺炎和新冠病毒的译法。梳理了科技术语翻译标准和多模态大数据语境理论框架。基于科技术语与翻译方面权威的规范文献的国际国内标准和术语翻译标准的相关研究等可归纳为准确、简明、一致、规范的术语翻译标准;多模态大数据语境则指术语可通过文本、图片、网页等多模态语境传播,整个网络具有多模态语境互文性。文章以新冠肺炎和新冠病毒术语翻译标准化为例,基于网络、数据库检索、图文等互文性语境,以及现有相关研究,分析在科普和学术论文场合的翻译惯例,根据术语翻译标准,更全面归纳了标准化汉英翻译,包括优选术语、全称、曾称和简称等,示范了英语科技论文中全称和简称的写作方式等,可为在线词典、机器翻译中术语优化和科技名词规范等术语翻译标准化相关工作提供参考。

A Model for Estimating Total Forest Coverage with Ground-Based Digital Photography

Vegetation fractional coverage (VFC) is one of the key indicators of vegetation distribution. In the work a measurement-based model was developed to derive total forest VFC (TG) as well as the VFC of trees (T) and shrub-grasses (G) separately in a subtropical forest area in Nanjing, China. Both upward and downward photographs were taken with a digital camera in 72 quadrats (10 m × 10 m each). Fifteen models were established and validated. Models jointly using both T and G performed better than those using the T and G separately. The best model, TG = T + G- 1.134 × T × G- 0.025 (R2 = 0.9115, P < 0.01, root mean squared error = 0.0789), is recommended for application. This model provides a good way to obtain total forest VFC values through taking tree and shrub-grass photos on ground below tree canopy rather than above tree canopy.

一种改进的稀疏表示的手写数字识别

提出一种改进的稀疏表示的手写数字识别方法。首先将样本字符块训练成过完备字典,然后通过改进的基于L1/2正则化算法进行系数分解,最后通过求重构图像与原始图像的残差进行分类。实验采用标准的数字数据库MNIST进行手写数字识别,改进的稀疏表示方法较其他方法能够有较高识别率,达到98%以上,并且具有很好的噪声鲁棒性。

A machine learning framework for low-field NMR data processing

Low-field(nuclear magnetic resonance)NMR has been widely used in petroleum industry,such as well logging and laboratory rock core analysis.However,the signal-to-noise ratio is low due to the low magnetic field strength of NMR tools and the complex petrophysical properties of detected samples.Suppressing the noise and highlighting the available NMR signals is very important for subsequent data processing.Most denoising methods are normally based on fixed mathematical transformation or handdesign feature selectors to suppress noise characteristics,which may not perform well because of their non-adaptive performance to different noisy signals.In this paper,we proposed a“data processing framework”to improve the quality of low field NMR echo data based on dictionary learning.Dictionary learning is a machine learning method based on redundancy and sparse representation theory.Available information in noisy NMR echo data can be adaptively extracted and reconstructed by dictionary learning.The advantages and application effectiveness of the proposed method were verified with a number of numerical simulations,NMR core data analyses,and NMR logging data processing.The results show that dictionary learning can significantly improve the quality of NMR echo data with high noise level and effectively improve the accuracy and reliability of inversion results.

新型混合字典学习算法改进图像超分辨率的研究

目前机器学习算法大都采用单层字典的学习训练设计,现从改进视觉效果、分辨率2个角度,设计了2层字典混合学习算法。采用经典的半耦合字典学习(SCDL)和模糊模型处理结合作为第1层字典学习,第2层则是针对第1层的残余图像进行重构,结合K值聚类以及K-SVD算法设计了第2层字典的训练过程。与经典SCSR、SCDL算法对比实验结果表明:改进算法的峰值信噪比与其他2种算法有了4%左右的提高,提高值在1 d B以上,表明了算法能够一定程度的提高重构图像的分辨率;算法的对比视觉效果看出,改进的算法能够明显改进重构质量,实现了图像视觉效果的改善。由于算法并不是以牺牲算法运算时间、速度为代价,这样其研究结果对于机器学习在图像领域的进一步推广与发展具有一定的参考价值。

MODEL OF UPPER OCEANIC CIRCULATIONS IN THE SOUTH CHINA SEA DURING NORTHEAST MONSOON

The large-scale upper oceanic circulation in the South China Sea (SCS) during the northeast monsoon was investigited using a 2 1/2-layer model inrolving entrainment and detraininent at the interface between the upper mixed layer and the seasonal thermocline. The model allows heat fluxes at the surface and at the interfaee with a reaxation scheme, the temperatures of the two active layers can vary. The model basin is idenical to the SCS lateral boundary with bottom topography of 50 m or more and is regarded as an enclosed basin by neglecting inflow and outflow through the straits, and is forced by the climetological wind stna of 12 calendar months. It was found tha the upper oceanic currents in winter were mainly wind-driven. Most aspects of streams reported by observations were simulated with eddyresolving.

NUMERICAL STUDY ON THE INTERANNUAL OSCILLATION OF SEA SURFACE TEMPERATURE IN THE SOUTH CHINA SEA

A two and a half layer oceanic model of wind-driven, thermodynamical general circulation is appliedto study the interannual oscillation of sea surface temperature (SST) in the South China Sea (SCS). Themodel consists of two active layers: the upper mixed layer (UML) and the seasonal thermocline, with themotionless abyss beneath them. The governing equations which include momentum, continuity and sea.temperature for each active layer, can describe the physics of Boussinseq approximation, reduced gravityand equatorial β-plane. The formulas for the heat flux at the surface and at the interface between twoactive layers are designed on the Haney scheme. The entrainment and detrainment at the bottom of theUML induces vertical transport of mass,momentum and heat, and couples of dynamic andthermodynamic effect.Using leap-frog integrating scheme and the Arakawa-C grid the model is forced bya time-dependent wind anomaly stress pattern obtained from category analysis of COADS. The numerical results indicate that

基于光滑L1/2正则化理论的地震数据重建

L1/2正则化比L1正则化有更稀疏的解,比L0正则化更易求解.本文将L1/2正则化引入到地震数据重建过程,提出了一种基于光滑L1/2正则化的地震数据重建方法.首先建立L1/2正则化地震数据重建模型,并利用光滑渐近函数逼近L1/2正则项,克服了L1/2正则化求解过程中的数值振荡问题;之后根据光滑L1/2正则化理论改进了字典学习算法,提高了冗余字典的训练效率;最后利用训练的冗余字典和半阈值迭代算法对地震数据进行恢复重建.对具有232道、每道751个采样点的地震炮集数据应用结果表明,与基于L1正则化的K-SVD重建方法相比,本方法重建结果的信噪比提高3.3 dB.在计算效率方面,本方法字典训练耗时仅为L1正则化K-SVD的1/3,重建耗时仅为L1正则化K-SVD一半的时间.