New Finite Difference Mapped WENO Schemes with Increasingly High Order of Accuracy

In this paper,a new type of finite difference mapped weighted essentially non-oscillatory(MWENO)schemes with unequal-sized stencils,such as the seventh-order and ninthorder versions,is constructed for solving hyperbolic conservation laws.For the purpose of designing increasingly high-order finite difference WENO schemes,the equal-sized stencils are becoming more and more wider.The more we use wider candidate stencils,the bigger the probability of discontinuities lies in all stencils.Therefore,one innovation of these new WENO schemes is to introduce a new splitting stencil methodology to divide some fourpoint or five-point stencils into several smaller three-point stencils.By the usage of this new methodology in high-order spatial reconstruction procedure,we get different degree polynomials defined on these unequal-sized stencils,and calculate the linear weights,smoothness indicators,and nonlinear weights as specified in Jiang and Shu(J.Comput.Phys.126:202228,1996).Since the difference between the nonlinear weights and the linear weights is too big to keep the optimal order of accuracy in smooth regions,another crucial innovation is to present the new mapping functions which are used to obtain the mapped nonlinear weights and decrease the difference quantity between the mapped nonlinear weights and the linear weights,so as to keep the optimal order of accuracy in smooth regions.These new MWENO schemes can also be applied to compute some extreme examples,such as the double rarefaction wave problem,the Sedov blast wave problem,and the Leblanc problem with a normal CFL number.Extensive numerical results are provided to illustrate the good performance of the new finite difference MWENO schemes.

THE FEKETE-SZEG?INEQUALITY AND SUCCESSIVE COEFFICIENTS DIFFERENCE FOR A SUBCLASS OF CLOSE-TO-STARLIKE MAPPINGS IN COMPLEX BANACH SPACES

Let C be the familiar class of normalized close-to-convex functions in the unit disk.In[17],Koepf demonstrated that,as to a function■in the class C,■By applying this inequality,it can be proven that‖a3|-|a2‖≤1 for close-to-convex functions.Now we generalized the above conclusions to a subclass of close-to-starlike mappings defined on the unit ball of a complex Banach space.

Inverse full state hybrid projective synchronization for chaotic maps with different dimensions

A new synchronization scheme for chaotic（hyperchaotic） maps with different dimensions is presented.Specifically,given a drive system map with dimension n and a response system with dimension m,the proposed approach enables each drive system state to be synchronized with a linear response combination of the response system states.The method,based on the Lyapunov stability theory and the pole placement technique,presents some useful features：（i） it enables synchronization to be achieved for both cases of n 〈 m and n 〉 m;（ii） it is rigorous,being based on theorems;（iii） it can be readily applied to any chaotic（hyperchaotic） maps defined to date.Finally,the capability of the approach is illustrated by synchronization examples between the two-dimensional H′enon map（as the drive system） and the three-dimensional hyperchaotic Wang map（as the response system）,and the three-dimensional H′enon-like map（as the drive system） and the two-dimensional Lorenz discrete-time system（as the response system）.

健康人膝关节股骨内侧髁软骨的T_(2) mapping研究

目的应用T_(2) mapping技术测量健康人膝关节股骨内侧髁负重区与非负重区各层软骨T_(2)值并分析其差异,探讨膝关节软骨分层、分区域MRI定量研究的价值。方法前瞻性纳入22名健康志愿者,其中男、女各11名,平均年龄(27.05±1.05)岁。共纳入38个膝关节,左膝20个,右膝18个。对志愿者行膝关节MRI矢状面T_(2) mapping检查,选取膝关节股骨内侧髁负重区35个、非负重区37个,并测量完整关节软骨上最厚处的T_(2)值。采用独立样本t检验和方差分析分别比较股骨内侧髁负重区与非负重区各层软骨的T_(2)值及各区域内关节软骨浅、中、深层的T_(2)值。结果股骨内侧髁负重区及非负重区的软骨各层T_(2)值由大到小依次为浅层、中层、深层,除非负重区软骨浅层与中层间的T_(2)值差异无统计学意义(P>0.05),余各2层间T_(2)值差异均有统计学意义(均P<0.05);负重区软骨中层、深层T_(2)值均小于非负重区(均P<0.05),负重区与非负重区软骨浅层的T_(2)值差异无统计学意义(P>0.05)。结论健康人膝关节软骨依据T_(2)值差异可分为3层且负重区软骨T_(2)值更低,对膝关节软骨分层、分区域研究具有可行性。

SOME EULER SPACES OF DIFFERENCE SEQUENCES OF ORDER m

Kizmaz [13] studied the difference sequence spaces ∞（A）, c（A）, and co（A）. Several article dealt with the sets of sequences of m-th order difference of which are bounded, convergent, or convergent to zero. Altay and Basar [5] and Altay, Basar, and Mursaleen [7] introduced the Euler sequence spaces e0^r, ec^r, and e∞^r, respectively. The main purpose of this article is to introduce the spaces e0^r△^（m））, ec^r△^（m））, and e∞^r△^（m））consisting of all sequences whose mth order differences are in the Euler spaces e0^r, ec^r, and e∞^r, respectively. Moreover, the authors give some topological properties and inclusion relations, and determine the α-, β-, and γ-duals of the spaces e0^r△^（m））, ec^r△^（m））, and e∞^r△^（m））, and the Schauder basis of the spaces e0^r△^（m））, ec^r△^（m））. The last section of the article is devoted to the characterization of some matrix mappings on the sequence space ec^r△^（m））.

ON THE m^(th) ORDER DIFFERENCE SEQUENCE SPACE OF GENERALIZED WEIGHTED MEAN AND COMPACT OPERATORS

In this article, using generalized weighted mean and difference matrix of order m, we introduce the paranormed sequence space l（u, v, p; △（m））, which consist of the sequences whose generalized weighted △（m）-difference means are in the linear space l（p） defined by I.J.Maddox. Also, we determine the basis of this space and compute its α-, β- and γ-duals. Further, we give the characterization of the classes of matrix mappings from l（u, v, p, △（m）） to l∞, c, and co. Finally, we apply the Hausdorff measure of noncompacness to characterize some classes of compact operators given by matrices on the space lp（U, v, △（m）） （1 ≤ p 〈 ∞）.

A GENERALIZED SEMICONJUGACY IN DIFFERENCE EQUATIONS

Difference equations arise in many fields. This article is concerned to general- ization of semiconjugacy in difference equations. In fact, H. Sedaghat in [7] investigated the semiconjugacy in difference equations where the factor maps are one-dimensional. We gen- eralize the definition of semiconjugacy of maps, where the factor map is multi-dimensional. This generalization is very useful. By this generalization, we can investigate the dynamics of many difference equations especially the dynamics of systems of higher order difference equations. Some systems of difference equations are investigated using the semiconjugacy property.

Comparison of Digital Maps: Recognition and Quantitative Measure of Changes

A new methodology of comparing digital raster maps was proposed which allows not only detecting changes in the maps, but also obtaining quantitative measures of the importance of selected differences. Procedure of object interpretation of satellite images and forming of OMT (Object Map of Territory) is described. A list of allowable differences between two OMTs is defined. Two steps technique of quantitative measuring is proposed. At the first stage functions are constructed for calculating local measures of differences in the amount, areas and locations of objects on the map, as well as relations between the objects. In the second stage local measures are used to calculate the integral measure in order to get generalized assessment of difference between maps. The methods for constructing functions which calculate local and integral measures of differences are described. Examples of comparing and measuring the differences between OMTs are provided. Obtained results by utilizing this technique can be used to analyze trends, forecast of development and might be helpful for choosing most efficient scenarios for sustainable spatial planning and land management.

Mapping the Dyke Swarms Emplaced within the Different Archean Cratons of the Indian Shield Using Google^(TM) Earth Images and Arc GIS^(TM) Techniques

The Indian shield comprises a number of Archean–Paleoproterozoic cratonic blocks and predominantly Meso–Neoproterozoic mobile belts with Archean protoliths.All these ancient cratons were thought to be integral parts of

Comparison of detection results of hypoxic-ischemic encephalopathy at different degrees in infant patients between brain electrical activity mapping, transcranial Doppler sonography and computer tomography examinations

BACKGROUND： It has been proved that brain electrical activity mapping （BEAM） and transcranial Doppler （TCD） detection can reflect the function of brain cell and its diseased degree of infant patients with moderate to severe hypoxic-ischemic encephalopathy （HIE）. OBJECTIVE： To observe the abnormal results of HIE at different degrees detected with BEAM and TCD in infant patients, and compare the detection results at the same time point between BEAM, TCD and computer tomography （CT） examinations. DESIGN ： Contrast observation SETTING： Departments of Neuro-electrophysiology and Pediatrics, Second Affiliated Hospital of Qiqihar Medical College. PARTICIPANTS： Totally 416 infant patients with HIE who received treatment in the Department of Newborn Infants, Second Affiliated Hospital of Qiqihar Medical College during January 2001 and December 2005. The infant patients, 278 male and 138 female, were at embryonic 37 to 42 weeks and weighing 2.0 to 4.1 kg, and they were diagnosed with CT and met the diagnostic criteria of HIE of newborn infants compiled by Department of Neonatology, Pediatric Academy, Chinese Medical Association. According to diagnostic criteria, 130 patients were mild abnormal, 196 moderate abnormal and 90 severe abnormal. The relatives of all the infant patients were informed of the experiment. METHOOS： BEAM and TCD examinations were performed in the involved 416 infant patients with HIE at different degrees with DYD2000 16-channel BEAM instrument and EME-2000 ultrasonograph before preliminary diagnosis treatment （within 1 month after birth） and 1,3,6,12 and 24 months after birth, and detected results were compared between BEAM, TCD and CT examinations. MAIN OUTCOME MEASURES： Comparison of detection results of HIE at different time points in infant patients between BEAM. TCD and CT examinations. RESULTS： All the 416 infant patients with HIE participated in the result analysis. （1） Comparison of the detected results in infant patients with mild HIE at different time points after birth between BEAM, TCD and CT examinations： BEAM examination showed that the recovery was delayed, and the abnormal rate of BEAM examination was significantly higher than that of CT examination 1 and 3 months after birth [55.4%（72/130）vs. 17.0% （22/130 ）,x^2=41.66 ;29.2% （ 38/130 ） vs. 6.2% （ 8/130 ）, x^2=23.77, P 〈 0.01 ], exceptional patients had mild abnormality and reached the normal level in about 6 months. TCD examination showed that the disease condition significantly improved and infant patients with HIE basically recovered 1 or 2 months after birth, while CT examination showed that infant patients recovered 3 or 4 months after birth. （2） Comparison of detection results of infant patients with moderate HIE at different time points between BEAM, TCD and CT examinations： The abnormal rate of BEAM examination was significantly higher than that of CT examination 1,3,6 and 12 months after birth [90.8% （178/196）,78.6% （154/196）,x^2=4.32,P 〈 0.05;64.3% （126/196）,43.9% （86/196） ,x^2=16.44 ;44.9% （88/196） ,22.4% （44/196）,x^2=22.11 ;21.4% （42/196）, 10.2% （20/196）,x^2=9.27, P 〈 0.01]. BEAM examination showed that there was still one patient who did not completely recovered in the 24^th month due to the relatives of infant patients did not combine the treatment,. TCD examination showed that the abnormal rate was 23.1%（30/196）in the 1^st month after birth, and all the patients recovered to the normal in the 3^rd month after birth, while CT examination showed that mild abnormality still existed in the 24^th month after birth （1.0% ,2/196）. （3） Comparison of detection results of infant patients with severe HIE at different time points between BEAM, TCD and CT examinations： The abnormal rate of BEAM examination was significantly higher than that of CT examination in the 1^st, 3^rd, 6^th and 12^th months after birth[86.7% （78/90）,44.4% （40/90）,x^2=35.53;62.2% （56/90）,31.1% （28/90）,x^2=17.51 ;37.8% （34/90）,6.7% （6/90）, x^2=27.14, P 〈 0.01]. BEAM examination showed that mild abnormality still existed in 4 infant patients in the 24^th month after birth. TCD examination showed that the abnormal rate was 11.1% （10/90） in the 3^rd month after birth, and all the infant patients recovered in the 6^th month after birth. CT examination showed that the abnormal rate was 6.7%（6/90） in the 12^th month after birth, and all of infant patients recovered to the normal in the 24^th month after birth.CONCLUSION ： BEAM is the direct index to detect brain function of infant patients with HIE, and positive reaction is still very sensitive in the tracking detection of convalescent period. The positive rate of morphological reaction in CT examination is superior to that in TCD examination, and the positive rate is very high in the acute period of HIE in examination.

Inundation Maps for Extreme Flood Events at the Mouth of the Danube River

Hydrodynamic modeling is used to analyse the inundation behavior of St. George village during extreme flood events, in particular for a flood happened in spring 2006. The study reach, 4 km in length, is situated in the Danube Delta, at the mouth of St. George distributary and includes St. George village. Land and bathymetric surveys were used to create a digital terrain model (DTM) of the river channel and the village. By coupling the geometry with hydrologic data, a 2D hydrodynamic model was built up with the help of the CCHE2D code (University of Mississippi). The model is based on integrating Saint-Venant shallow waters (depth averaged) equations through finite-difference implicit numerical scheme. It was calibrated in terms of roughness coefficients on measured values of water surface elevation registered in the St. George port. Flood maps obtained from computations were compared to satellite images from the same days of the spring 2006 extreme event. Inundation behaviour of the St. George village was analysed for different scenarios of river hydrological and sea level (variable because of wind waves) conditions. Findings were compared with high water marks and inhabitants testimonials. The model proved that sea level has a higher influence upon the inundability of the area than the river flood events.

基于映射距离比离群因子的离群点检测算法

针对基于邻近性的离群点检测方法需要花费大量时间过滤正常点,并且在检测全局离群点时难以检测出局部离群点的问题,提出一种基于映射距离比离群因子离群点检测(MDROF)算法。首先,为了减少正常点在检测过程中的时间消耗,给出了差异相似度的概念,通过定义差异相似度剪枝因子过滤掉数据集中的大部分正常点。其次,定义映射k距离,通过映射距离与可达距离的比值刻画数据对象的局部离群程度,通过可达密度刻画数据对象的全局离群程度。最后,结合数据对象相互近邻点的平均排位定义映射距离比离群因子来检测离群点。在人工数据集以及真实数据集上分别对该算法与其他经典的离群点检测算法在精确率、AUC值和离群点发现曲线上进行实验对比分析。实验结果证明MDROF算法在离群点检测的准确性和稳定性上明显优于对比算法。

基于多目标遗传算法的8×8 S盒的优化设计方法

混沌系统具有非线性、伪随机性、初始值敏感等特性,为基于动力系统构造性能良好的S盒提供了基础,进一步保证了分组加密算法安全性.目前,基于混沌构造S盒的方法大多数针对单个性能指标进行优化,难以获得全面的性能提升.针对此问题,结合混沌映射与多目标遗传算法,提出了一种新的S盒设计方法.首先,利用混沌映射的特性产生初始S盒种群;然后,以S盒的非线性度和差分均匀性为优化目标,基于遗传算法框架对上述两指标进行优化.针对S盒的特点,在优化算法中引入了交换操作,设计了新的变异操作以及非支配序集计算,有效提升了S盒的非线性度和差分均匀性.实验结果表明该算法产生的S盒其差分均匀度为6,非线性度值至少为110,有效提升了S盒的综合性能.

博物馆展示交互设计发展态势可视化分析

目的对国内外博物馆展示交互设计的相关文献进行分析与总结,探讨该领域的研究热点、演进历程、发展趋势及国内外发展差异,并找出差异形成的原因,为今后博物馆展示交互设计的发展提供思路。方法以1995一2023年CNKI中国知网、Webof Science两大文献数据库作为数据来源,以1401篇博物馆展示交互设计相关文献为分析对象,经CiteSpace软件的运行,就国内外学界的已有研究生成相应的关键词共现图谱,并生成关键词聚类合成知识谱图,对该领域文献的发文统计、文献分布情况、作者、机构及关键词等内容进行梳理、知识图谱的生成及可视化分析。结果研究结果表明,国内外针对博物馆展示交互设计的研究都围绕观众展开,同时也都强调利用数字技术进行多感官体验的打造。但国外研究更注重以用户体验为中心的设计理念,研究重点聚焦以参与需求为目的社交空间等维度。国内研究则更多关注以数字展示为手段的展示内容上的感官呈现,更注重博物馆文化的传播。结论由于国内外博物馆展示交互设计中展陈设计理念、空间叙事逻辑、传播媒介偏向的不同,出现了基于不同研究视角的发展差异。伴随着社会职能的不断拓展与科学技术的不断进步,未来博物馆将在技术应用、展示功能、职能变革和交互体验等方面产生更多突破。

融合T-分布小波变异的混沌鲸鱼优化算法

针对鲸鱼优化算法难以跳出局部最优导致收敛精度不足的问题,提出一种融合了T-分布小波变异和多项式差分学习策略的鲸鱼优化算法.该算法首先引入Circle混沌扩大搜索范围,提高收敛速度;然后采用T-分布小波变异策略平衡全局和局部搜索能力;最后采用多项式差分学习策略改进算法的优化精度.对3种改进策略作单一引入的仿真对比分析,并将改进的鲸鱼优化算法在12个可变维度的基准测试函数上进行仿真,对本文改进的鲸鱼优化算法与其他改进策略的鲸鱼优化算法以及其他几种智能算法进行比较.结果表明,基于T-分布小波变异和多项式差分学习策略的改进鲸鱼优化算法具有较好的稳定性,收敛速度和精度更好.

基于参数特征映射的多站时差测量实现

在现代定位系统中,传统的时差测量方法往往受限于信号调制方式、噪声干扰以及硬件实现复杂度等因素,难以保持高精度和实时性。针对上述问题,本文设计一种基于参数特征映射的多站时差定位系统中时差测量方法,由主站检测并产生参考信号,广播至各从站;各站根据此参考信号基于频域互相关算法完成时差测量。该方法有效提高二进制相移键控(binary phase shift keying,BPSK)信号、四相相移键控(quadrature phase shift keying,QPSK)信号、频移-相移复合调制(frequency shift keying-phase shift keying,FSK-PSK)信号等时差测量精度。本文给出了基于现场可编程逻辑门阵列(field programmable gate array,FPGA)时差测量方法的硬件实现,采用实时动态压缩方法,FPGA算法实现资源减少50%;采用抛物线拟合方法,提高时差估计精度;采用基于参数特征映射的数据传输方法,保障多站数据的完备、避免数据缺失和冗余的同时,数据传输量降低95%。仿真与试验测试结果表明,信噪比(signal-to-noise ratio,SNR)大于等于5 dB时,PSK调制信号时差测量精度优于5 ns;对于前沿缓变调制信号,随着脉冲上升沿宽度增大,时差测量精度无明显变化;最后,在外场试验与飞行试验结果中验证方法的有效性与可行性,为高精度多站时差定位系统的实际应用提供了有力支持。

基于虚拟坐标的矢量地图差值扩展可逆水印方法

传统差值扩展技术受数据相关性限制,直接应用于矢量数据可逆水印方案易导致较低的水印容量和较大的数据失真,对顶点相关性低的矢量地图,水印效果更差。为实现更高的水印容量并控制数据失真,该文针对传统差值扩展技术提出改进:①在顶点坐标之间插入虚拟坐标,以虚拟坐标为参考点计算坐标差值;②将计算得到的坐标差值直方图向左平移,使直方图峰值点与原点重合;③水印以差值扩展的方式嵌入平移后的坐标差值中。实验结果表明:该算法的水印容量为2 bit/点,至少是传统差值扩展水印容量的6倍;与传统差值扩展方法相比,数据失真更小,原始地图坐标与水印地图坐标的RMSE和地图坐标最大改变量Max-R均大幅降低,算法严格可逆且对顶点相关性低的矢量地图水印效果仍然很好。

基于绿视率和NDVI的城市街道景观分析与优化研究

街道景观空间对市民健康和城市风貌具有重要影响。既往研究中常以归一化植被指数(NDVI)和绿视率(GVI)来分别代表二维和三维的绿色指标,但对二者的指标相关性研究甚少。采用基于深度学习的图像语义分割方法分析百度街景计算代表性街道的GVI,利用GF-1卫星数据计算NDVI,比较分析城市街道的GVI和NDVI指标特征及相关性。结果表明,1)中山市中心城区各代表街道GVI指标参差不齐,从8.06%到36.00%,其中石岐街道兴中道GVI最高;2)各街道观测点的NDVI均值随着缓冲区尺度的增加也随之呈现出不同变化,NDVI均值具有强烈的尺度敏感性;3)50 m GVI和DNVI均值的皮尔逊相关系数最高,达到0.832。在此基础上分析街道景观存在的不足并给出优化建议,为城市街景评估、空间优化、景观提升提供参考。