一种基于改进Softplus激活函数的卷积神经网络模型

为提高Softplus函数在神经网络中的性能,针对Softplus函数的缺点提出了一种基于改进Softplus激活函数的卷积神经网络模型。根据"输出均值接近零的激活函数可以提升神经网络的学习性能"原理,首先对原函数的输出向下平移缓解Softplus激活函数的均值偏移现象;然后对调整后的输出乘以一个参数调整函数在正数部份的坡度和负数部分的饱和点位置,以缓解在训练过程中出现的梯度消失/溢出现象。最后在MNIST、CIFAR-10和CIFAR-100数据集上的实验结果表明,同其它常用激活函数相比,改进后的Softplus函数取得了较好的识别率。     

基于Softplus函数的双隐含层BP神经网络的公路客运量预测

为了提高预测模型的精度,提出一种基于Softplus激活函数的双隐含层BP神经网络的预测方法,提高了模型的非线性学习和泛化能力及预测精度,并改善了网络性能。将该方法应用于公路客运量实际预测中进行有效性验证,结果表明该方法对公路客运量有更好的非线性拟合能力和预测准确性。     

基于深度残差网络的车标识别

针对车标识别准确率的问题, 提出一种基于ResNet-18模型改进残差网络的车标识别算法. 首先, 利用残差网络并对其进行改进, 使用改进的线性修正单元Leaky ReLU激活函数代替原激活函数; 其次, 调整传统的残差网络结构, 将批量标准化和激活函数放在卷积层前, 并减少网络参数以加速网络训练. 实验结果表明, 改进后的残差网络模型识别准确率达99.8%.     

求解非线性互补问题的一种光滑化算法

求解非线性互补问题是利用光滑逼近函数将其转化为光滑方程组。提出了非线性互补问题的一个新的光滑逼近函数,并使用光滑化算法求解非线性互补问题。对P0函数的非线性互补问题,证明了算法的收敛性,数值实验表明算法的有效性。     

深度学习神经网络的新型自适应激活函数

构造一个含有参数的光滑激活函数用于深度学习神经网络, 通过基于误差反向传播算法建立参数的在线修正公式, 避免了梯度弥散、 不光滑及过 拟合等问题. 与一些常用的激活函数进行对比实验结果表明, 新的激活函数在多个数据集上效果均较好.     

深度学习神经网络的新型自适应激活函数

构造一个含有参数的光滑激活函数用于深度学习神经网络, 通过基于误差反向传播算法建立参数的在线修正公式, 避免了梯度弥散、 不光滑及过 拟合等问题. 与一些常用的激活函数进行对比实验结果表明, 新的激活函数在多个数据集上效果均较好.     

基于稀疏模型和Gabor小波字典的跟踪算法

基于稀疏表示理论的目标跟踪方法可以通过激活少量神经元完成目标的动态跟踪,但是要求在当前图像背景中的遮挡或者目标物的姿态变化是可以进行稀疏表示的小面积范围.针对这一问题,基于Gabor函数和稀疏理论提出一种强鲁棒性的目标跟踪算法.该算法首先使用目标模板在初始帧中创建Gabor字典,其次使用该字典对候选目标完成稀疏表示,最后通过对Gabor字典的更新完成目标跟踪.实验结果表明了算法的有效性.     

冲击噪声下基于Lorentzian范数的CSR参数估计

针对现有重构算法及其改进算法在压缩感知雷达(CSR)参数估计中存在的稳健性不强、适用性不广等问题,提出了一种适用于冲击噪声背景的鲁棒性算法——Lorentzian-ISL0(基于Lorentzian范数的改进光滑l0范数).建立CSR参数估计的稀疏线性模型,并基于Lorentzian范数和高斯函数稀疏正则化,构造冲击噪声下稳健的优化目标函数;修正优化目标函数的牛顿方向,并沿修正方向对估计值进行更新,直至收敛.仿真实验结果表明:与已有算法相比,本文方法计算复杂度更小,支撑集重构更精确,信号重构精度更高.     

基于深度神经网络的入侵检测方法

为改善传统机器学习技术解决海量网络数据和复杂入侵模式对信息网络的入侵检测的不足,提出一种基于深度神经网络的入侵检测方法.采用神经元映射卷积神经网络(NPCNN)为网络结构,使用较少的连接和参数,具有易于训练和泛化能力强等优点.在训练过程中,使用Re LU激活器作为非线性激活函数,采用Adam算法进行模型学习,从而避免了传统深度网络须进行预训练的过程.在NSL-KDD数据集上的实验结果表明:提出的方法较基于传统机器学习的入侵检测方法具有良好的特征表征学习和分类能力,且随着数据量的增大,模型的分类精度有较大的提升.     

一种非光滑函数的二阶梯度微分方程求解算法

为了更好地解决复杂非线性多目标模型求解问题,提出一种非光滑函数的二阶梯度微分方程求解算法.结合非光滑函数针对二阶梯度微分方程中的凸函数性质进行分析和演化,规范凸函数的一阶和二阶性质定义,从而求解常微分方程和偏微分方程.进一步根据非光滑函数的基本原理,对非光滑函数导数进行求解,并对非光滑函数的二阶梯度微分方程的误差数值进行检测和修正,保证二阶梯度微分方程求解算法的有效性同时提高算法的防滑性能,最后通过对比实验证实了非光滑函数的二阶梯度微分方程求解算法在实际应用过程中的可行性.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.