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1.
Gk-frugal列表色数一般记作chkG,关于稀疏的k-frugal列表色数上界,有以下3个结论:? k3,如果图G满足madG<3-a(其中0<a13)且ΔGk+3a-3,则chkG=?k-1+1? k4,如果图G满足madG<3,则chkG?k-1+2? k4,如果图G满足madG<103,则chkG?k-1+3。  相似文献   

2.
基于一种选择系数矩阵A的工作列的策略,提出了求解大型线性最小二乘问题的一种不同的贪婪Gauss-Seidel方法,并对该方法进行了收敛性分析。数值实验表明,在相同的精度下,所提方法在计算时间上优于文献提出的贪婪随机坐标下降方法。  相似文献   

3.
以长江口长兴岛潜堤后方滩涂圈围工程为研究背景,采集堤坝地基土样,根据实际工况应力路径设计不同围压和动静应力组合,对淤泥质软黏土进行动三轴试验,探究地基土在分级施工加载与波浪荷载耦合作用下软黏土应变、孔压特性以及强度弱化特性。研究结果表明:耦合应力加载后土样的应力-应变曲线呈现应变软化和强度弱化特性,分级加载效应可使应变及孔压增量减少,且应变增量、孔压增量与循环振后静强度折减度,均和固结围压、静偏应力比、动偏应力比等因素相关。当动偏应力比相同时,深度较浅土层围压较小,静偏应力比反而较大,其应变与孔压增量越大,静强度衰减越明显。随着动偏应力比增大,土单元的应变增量与孔压增量、强度折减度有不同程度的增大,并且不同深度的差异性较大。在此基础上,分别对强度折减度β、广义综合剪应变γgs及广义综合孔压增量比Δu/σ3进行了量化,并对(γgs-β)及(Δu/σ3-β)相关性进行了探讨。研究结果对于指导具体工程实践具有一定的参考价值。  相似文献   

4.
为探究富营养化水体中藻类的新型治理技术,通过水热法和高温煅烧法,使颗粒活性炭(AC)表层上负载铜铁双金属氧化物Cu-FeOx,制得可回收的Cu-FeOx@AC复合催化剂。以XRD、SEM、FTIR和XPS对Cu-FeOx@AC的表征为基础,研究Cu-FeOx占AC的负载比、过一硫酸盐(PMS)使用量、初始pH及不同反应体系对除藻的影响,探究Cu-FeOx@AC活化过一硫酸盐体系的除藻效能。Cu-FeOx@AC活化过一硫酸盐体系反应机理,通过自由基淬灭实验、XPS表征进行探究。结果可知,初始pH为6,初始藻细胞密度为1.4×109个/L,使用催化剂0.5 g/L,PMS 0.2 g/L时,反应90 min,该体系对藻的降解率有97.25%。在该体系中,藻细胞能被吸附在Cu-FeOx@AC复合催化剂表面,在铜、铁不同价态离子的转换及AC的协同作用下,产生空穴、·O2-·OHSO4-·,单线态氧等多种氧化基团而被去除。  相似文献   

5.
以气流流经固体壁面产生的气动声源为研究对象,以力点源对应的偶极子气动声源声波动方程的声压解为基础,利用流场中声源辐射声压和脉动力、脉动力和压力梯度的关系,建立偶极子气动声源辐射声压与流场压力梯度的关系式;利用两偶极子声源可组成一四极子声源的概念,建立四极子气动声源辐射声压与流场脉动速度的关系式。最后,以圆柱绕流为研究对象,采用上述两关系式并结合数值仿真计算方法,得到圆柱绕流的偶极子和四极子气动声源大小和分布特征。结果表明:偶极子气动声源向远场的声辐射声压由??p?t决定,四极子气动声源向远场的声辐射声压由?2ur2?t2决定。  相似文献   

6.
求解线性方程组的稀疏解在图像重构、信号处理和机器学习等领域中具有广泛的应用,通过引入l1-范数正则化,可以转化为求解一个约束优化问题。基于一种选择系数矩阵工作行的概率准则,提出了稀疏贪婪随机Kaczmarz算法,并给出了有噪声干扰和无噪声干扰情况下该算法的收敛性分析。理论表明本文算法的收缩因子小于随机稀疏Kaczmarz算法的收缩因子。数值实验验证了本文算法的有效性。  相似文献   

7.
通过加湿除湿蒸发实验,对高盐工业废水34个不同水样采用了加湿除湿技术进行脱盐处理。在所得实验数据的基础上,对加湿除湿技术在实际工业中的普遍应用进行了可行性研究,并结合不同高盐工业废水的水质特点和处理效果,总结了判定该方法处理高盐工业废水的效果的一般规律。结果表明,实验中所有废水的冷凝液的电导率下降百分比ησ均在80.0%以上,最高可达99.9%;冷凝液的盐度均可达到生化处理标准,其中,有32个废水样的冷凝液的电导率可降到2 000 μS?cm-1以下。另外,加湿除湿技术对沸点比水高的盐类物质的去除效果较为彻底,对沸点比水低且电离常数较大的盐类物质也有较好的去除效果,而对沸点比水低且电离常数较小的盐类物质的去除效果较差。  相似文献   

8.
通过一系列刚性模型测压风洞试验,研究了矩形截面高层建筑立面面风压极值的变化特征,并与我国建筑结构荷载规范GB 50009—2012中的相关规定进行了对比,分析了受压面的面积、水平尺度及竖向尺度的影响,给出了更合理的尺度参数。试验结果表明,随受压面尺度的增加,面风压极值逐渐减小,当足尺面积达到50 m2时,面风压正极值的尺度折减系数在0.9左右,而负极值的尺度折减系数在0.8左右。我国建筑结构荷载规范对围护结构风荷载的尺度折减方法将导致面风压极值的低估,尤其是面风压正极值。以作用面面积、对角线长度和宽度作为尺度参数描述面风压极值折减系数的变化规律都不合理,建议采用以受压面的水平尺度b、竖向尺度h和整个建筑迎风面宽度B确定的综合尺度参数(b0.85h0.15/B)来描述建筑立面上面风压极值的尺度折减系数的变化规律。  相似文献   

9.
为了实现施工期盾构管片上浮过程的智能预测,采用动力水准仪对施工期盾构管片上浮过程进行自动化监测并建立了基于卷积神经网络?长短期记忆(CNN-LSTM)深度学习算法的管片上浮过程智能预测模型。结果表明:管片上浮阶段呈现出“阶梯状”,即管片上浮主要发生在盾构掘进期间,且掘进状态的上浮量最大,占峰值的75.24 %~98.29 %;CNN-LSTM模型对施工期盾构管片上浮过程具有较好的预测效果,在训练集上的均方误差MSE、平均绝对误差MAE和决定系数R2分别为0.038 7、0.148 2和0.999 3,在测试集上为0.030 7、0.138 9和0.801 9;相较于反向传播(BP)模型,CNN-LSTM模型在训练集与测试集上的性能均有所提升,且测试集的提升更明显,最高可达89.71 %。研究结果可为盾构管片上浮的现场实测及预防处治提供新思路。  相似文献   

10.
研究了路径直积图Pn×Pm的意大利控制数。结合计算机构造证明和数学推导证明,确定了Pn×P1Pn×P2Pn×P3的意大利控制数,并给出了Pn×Pm m4)意大利控制数的界。  相似文献   

11.
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.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
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。  相似文献   

14.
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  相似文献   

15.
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  相似文献   

16.
17.
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.  相似文献   

18.
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).  相似文献   

19.
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.  相似文献   

20.
Advances in wireless technologies and positioning technologies and spread of wireless devices, an interest in LBS (Location Based Service) is arising. To provide location based service, tracking data should have been stored in moving object database management system (called MODBMS) with proper policies and managed efficiently. So the methods which acquire the location information at regular time intervals then, store and manage have been studied. In this paper, we suggest tracking data management techniques using topology that is corresponding to the moving path of moving object. In our techniques, we update the MODBMS when moving object arrived at a street intersection or a curved road which is represented as the node in topology and predict the location at past and future with attribute of topology and linear function. In this technique, location data that are corresponding to the node in topology are stored, thus reduce the number of update and amount of data. Also in case predicting the location,because topology are used as well as existing location information, accuracy for prediction is increased than applying linear function or spline function.  相似文献   

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