一种改进的贝叶斯网络知识合成算法

为了解决贝叶斯网络知识合成中的不一致问题,对现有的算法进行了改进.改进后的算法在现有方法的基础上,引入了约束集不一致时的知识合成算法,在知识合成迭代过程中,通过对联合概率分布和概率知识的双向修正,在每一步迭代过程中降低了不一致度,从而实现了贝叶斯网络知识合成时对不一致概率知识的处理.实验结果表明,改进后的算法不仅能够处理概率知识之间相互不一致问题,而且能够处理概率知识与网络结构不一致问题.     

基于近似零范数的子空间迭代稀疏分解算法

针对近似零范数算法单参数代价函数不能协调近似精度与噪声容限的问题,提出了基于多参数代价函数的改进算法.在此基础上,利用子空间表示的方法确定了满足方程的源信号矢量空间,以此约束迭代算法的搜索范围,提高算法效率.理论分析和仿真实验表明,基于矢量空间迭代的算法收敛速度更快.此外,代价函数的改进在保持算法性能随源信号活跃概率变...     

MIMO系统的迭代降维并行检测算法

针对传统多输入多输出(MIMO)系统检测算法先检测的子流分集度较低以及错误传播的问题,提出了一种改进的迭代降维并行检测算法.该算法在每次迭代内对第1个子流遍历取值,其余子流采用排序连续干扰消除(OSIC)算法进行检测,在每次迭代结束时仅输出分集度最高的首子流的估计值,在迭代间通过干扰消除降低待检测子流的维度.仿真结果表明:该算法能以较低的复杂度代价获得逼近最大似然检测算法的差错概率性能;在4×4、QPSK调制的MIMO系统中,相对于传统的OSIC算法,文中算法在误比特率为10-3时获得了9.3 d B的增益.     

基于改进杂草优化算法的最优线性协作频谱感知

线性加权协作频谱感知模型下,针对虚警概率最大化检测概率的问题,提出了一种基于改进入侵性杂草优化算法的协作频谱感知方案。算法中的可行解与频谱协作感知模型中的权重向量相对应,通过寻求最优权重向量,来达到最大化检测概率的目的。同时将改进后的杂草算法与传统的杂草算法及基于修正偏差因子方法性能进行对比。结果表明,改进后的杂草算法可根据当前噪声环境合理分配系统的权重系数,以较小的迭代次数找到更优的权重向量,在虚警概率一定的前提下,获得高的检测概率,其性能优于原始MDC算法。     

货物三维装箱问题建模及其乌鸦搜索算法优化

针对货物三维装箱问题建立三维装箱模型.在模型中,为避免货物在运输过程中转弯时由于偏心导致翻车现象的发生,加入了考虑转弯时重心约束,得到重心区域投影为等腰三角形或者等腰梯形.货物放置规则中扩大了剩余空间区域,增加了解的多样性.在算法中,为了提高迭代收敛速度,增强其全局寻优的能力,采用改进的乌鸦搜索算法对模型进行求解与优化.在改进算法中,提出并引入了多概率随机游走策略和解修复策略.解修复策略使得算法适用于模型求解,尽可能增加解的多样性.多概率随机游走策略是种群迭代后继续以多种不同的概率进行随机游走,使得算法全局寻优能力更强.仿真实例与基准函数测试结果表明,改进后的算法优化效果明显.     

PageRank-Pro: 一种改进的网页排序算法

根据网页点击信息改进了原有的PageRank算法, 利用Seidel迭代算法加快了迭代收敛 过程. 实验结果表明, 改进后的迭代算法效率提高23%左右.     

基于Broyden算法的概率积分法预计参数求取方法研究

以概率积分法为例对泰勒级数展开法的不足进行了深入研究.首先给出了概率积分法的预计参数,分析了根据参数定义和实测资料直接求定法的不足;论述了曲线拟合的基本思想和泰勒级数展开法的迭代步骤,指出泰勒级数展开法具有迭代易失真、收敛速度慢以及计算量大等不足;针对这些不足提出借助Broyden算法的基本思想建立迭代模型,并给出了新模型的计算步骤;最后对改进前、后的算法进行了对比分析,验证了改进后的算法的优越性.图1,表2,参13.     

关于半收敛问题的探讨

针对实际CT系统中的不完全数据图像重建算法半收敛问题,分析了迭代外插算法收敛性与引入的参数因子、已知的检测数据的关系,并给出了改进的迭代外插算法.数值实验结果表明迭代外插算法迭代过程有时是发散的,存在半收敛问题,而改进的迭代外插算法是收敛的.     

一种改进的AdaBoost算法——M-AsyAdaBoost

提出一种Asymmetric AdaBoost改进算法——M-Asy AdaBoost.M-Asy AdaBoost算法通过新的样本权重分配方式可以确保训练过程不失败;分类器权重采用对正样本的分类错误率形成优化权重,突出对正样本的识别能力,提高检测概率;并且通过对加入分类器集的分类器的限制,使检测概率单调增加.该算法在较低虚警概率下,达到高检测概率.计算机仿真结果验证了算法的正确性.     

CDMA中的QAM调制迭代PDA联合检测方法

为提高检测器性能并在检测器和信道解码器之间充分利用已知信号信息,多天线系统的广义概率数据关联检测算法被推广到多用户联合检测中.基于Turbo迭代原理,通过基于此算法的迭代多用户检测器和多电平正交调制以及软入软出的前向纠错编码的结合,提出一种软入软出的广义概率关联算法与软入软出的信道解码方法有机结合的新型迭代多用户检测方法.该方法利用外部信息在检测器与解码器之间的交换,进行干扰抵消并进行联合解码和判决.计算机仿真显示该方案收敛所需的迭代次数比传统的使用线性最小均方误差的联合检测解码方案少5次左右,且其误比特率性能接近最大似然接收机的性能.     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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