Robustness of the octupole collectivity in 144Ba within the cranking covariant density functional theory in 3D lattice

The octupole deformation and collectivity in octupole double-magic nucleus 144Ba are investigated using the Cranking covariant density functional theory in a three-dimensional lattice space.The reduced B(E3)transition probability is implemented for the first time in semiclassical approximation based on the microscopically calculated electric octupole moments.The available data,including the I-ωrelation and electric transitional probabilities B(E2)and B(E3)are well reproduced.Furthermore,it is shown that the ground state of 144Ba exhibits axial octupole and quadrupole deformations that persist up to high spins(I≈24h).

Explanation of Relation between Wave Function and Probability Density Based on Quantum Mechanics in Phase Space

The main problem of quantum mechanics is to elucidate why the probability density is the modulus square of wave function. For the purpose of solving this problem, we explored the possibility of deducing the fundamental equation of quantum mechanics by starting with the probability density. To do so, it is necessary to formulate a new theory of quantum mechanics distinguished from the previous ones. Our investigation shows that it is possible to construct quantum mechanics in phase space as an alternative autonomous formulation and such a possibility enables us to study quantum mechanics by starting with the probability density rather than the wave function. This direction of research is contrary to configuration-space formulation of quantum mechanics starting with the wave function. Our work leads to a full understanding of the wave function as the both mathematically and physically sufficient representation of quantum-mechanical state which supplements information on quantum state given solely by the probability density with phase information on quantum state. The final result of our work is that quantum mechanics in phase space satisfactorily elucidates the relation between the wave function and the probability density by using the consistent procedure starting with the probability density, thus corroborating the ontological interpretation of the wave function and withdrawing a main assumption of quantum mechanics.

Linearized Controller Design for the Output Probability Density Functions of Non-Gaussian Stochastic Systems

This paper presents a linearized approach for the controller design of the shape of output probability density functions for general stochastic systems. A square root approximation to an output probability density function is realized by a set of B-spline functions. This generally produces a nonlinear state space model for the weights of the B-spline approximation. A linearized model is therefore obtained and embedded into a performance function that measures the tracking error of the output probability density function with respect to a given distribution. By using this performance function as a Lyapunov function for the closed loop system, a feedback control input has been obtained which guarantees closed loop stability and realizes perfect tracking. The algorithm described in this paper has been tested on a simulated example and desired results have been achieved.

An Information Theory Approach to the Data Compression and Imaging System for Synthetic Aperture Radar （SAR）

Synthetic aperture radar (SAR) is portrayed as a multiple access channel. An information theory approach is applied to the SAR imaging system, and the information content about a target that can be extracted from its radar image is evaluated by the average mutual information measure. A conditional (transition) probability density function (PDF) of the SAR imaging system is derived by analyzing the system and a closed form of the information content is found. It is shown that the information content obtained by the SAR imaging system from an independent sample of echoes will decrease and the total information content obtained by the SAR imaging system will increase with an increase in the number of looks. Because the total average mutual information is also used to define a measure of radiometric resolution for radar images, it is shown that the radiometric resolution of a radar image of terrain will be improved by spatial averaging. In addition, the imaging process and the data compression process for SAR are each treated as an independent generalized communication channel. The effects of data compression upon radiometric resolution for SAR are studied and some conclusions are obtained.

南水北调中线工程冬季输水冰情风险研究

针对南水北调中线工程冬季输水冰情的安全运行问题,以南水北调中线工程河北段为研究对象,以热平衡理论为出发点推导出目标单元渠段的整体总热量变化公式;采用单因素局部分析法选出风险评价指标,基于概率论构建了风险评价指标之间的联合概率密度函数,将气象事件发生概率、热量变化率与冰情风险等级一一对应,从而对渠道冰情进行风险评估。对2021年1月6—8日南水北调中线工程河北段输水渠道冰情风险分析结果表明:在整个热交换过程中,短波辐射、蒸发和对流热交换是影响热量变化的主要因素,且夜间渠道的热量散失明显大于白天,加大了夜间发生冰情的风险;沙河节制闸—渠末段虽然与其他渠段风险等级一样,但其单位面积热量损失明显高于其他渠段,接近于极高风险,应加强对该渠段的实时监测并做好冰情防护。

A Stochastic Optimal Control Theory to Model Spontaneous Breathing

Respiratory variables, including tidal volume and respiratory rate, display significant variability. The probability density function (PDF) of respiratory variables has been shown to contain clinical information and can predict the risk for exacerbation in asthma. However, it is uncertain why this PDF plays a major role in predicting the dynamic conditions of the respiratory system. This paper introduces a stochastic optimal control model for noisy spontaneous breathing, and obtains a Shrödinger’s wave equation as the motion equation that can produce a PDF as a solution. Based on the lobules-bronchial tree model of the lung system, the tidal volume variable was expressed by a polar coordinate, by use of which the Shrödinger’s wave equation of inter-breath intervals (IBIs) was obtained. Through the wave equation of IBIs, the respiratory rhythm generator was characterized by the potential function including the PDF and the parameter concerning the topographical distribution of regional pulmonary ventilations. The stochastic model in this study was assumed to have a common variance parameter in the state variables, which would originate from the variability in metabolic energy at the cell level. As a conclusion, the PDF of IBIs would become a marker of neuroplasticity in the respiratory rhythm generator through Shr?dinger’s wave equation for IBIs.

网络环境下一种基于概率密度的信任博弈模型

随着可信计算的飞速发展,网络可信受到越来越多研究者的关注,信任模型的研究是其中主要研究内容之一.本文提出一种网络环境下基于概率密度的信任博弈模型,将信任模型的研究和网络环境相结合,把整个信任系统分为证据收集、基于概率密度的信任度量以及服务博弈三部分.证据收集模块利用数据挖掘和关联规则匹配进行信任证据的判断与评估.信任度量模块将信任细分为信任度和确定度,并按照熵原理使用概率密度函数来表现.虽然信任度量的目的是为了指导服务,单纯依靠信任度量并不可靠,服务博弈模块将度量结果结合支付矩阵进行博弈分析,计算出服务提供者行为的混合合纳什均衡策略.在三部分的分析过程中,与网络环境紧密结合,因此该方法对于网络可信的研究具有重要指导意义.

采煤机牵引部传动系统动态可靠性分析

考虑齿轮的时变啮合刚度、非线性侧隙等因素,根据3自由度齿轮集中质量模型,建立了采煤机牵引部的动力学整体模型,研究变速重载工况下系统的振动响应,获得了牵引部各位置的动态接触应力。考虑随机运动参数、结构参数与材料参数系统等的影响,基于鞍点逼近方法获得了系统功能函数的概率密度函数与概率分布函数,基于顺序统计量理论研究了载荷多次作用下牵引部传动系统的动态可靠性评价问题,计算结果表明:随着系统运转时间的增加,传动系统中齿轮接触应力分布均值增大且标准差减小;动态运转过程中,牵引系统首次运转是较为安全的,系统前期可靠性降低速度较快,后期可靠性递减速度较缓慢。

基于交叉熵理论的配电变压器寿命组合预测方法

对配电变压器进行状态评估和剩余寿命预测,是开展状态检修的重要前提。以变压器历年的健康指数HI为基础,提出了一种基于交叉熵理论的配电变压器寿命组合预测模型。在剩余寿命模型中运用故障概率密度函数并引入交叉熵理论动态确定改进灰色理论和改进马尔科夫两个单一预测算法的权重。模型考虑了配电变压器寿命周期中故障概率密度函数形状参数和尺度参数的变化,实现了对变压器全寿命周期健康指数的评估和预测,确定了健康指数的分布函数。最后通过实际数据验证了模型的有效性和合理性,相比于单一预测法更符合实际情况。

非线性函数的混沌优化方法比较研究

已有的混沌优化方法几乎都是利用Logistic映射作为混沌序列发生器,而Logistic映射产生的混沌序列的概率密度函数服从两头多、中间少的切比雪夫型分布,不利于搜索的效率和能力。为此,首先根据Logistic映射混沌轨道点密度函数的特点,建立改进的混沌-BFGS混合优化算法。之后,考虑到Kent映射混沌轨道点密度为均匀分布,建立了基于Kent映射的混沌-BFGS混合优化算法。然后对五种混合优化方法——不加改进的和改进的基于Logistic映射的混沌-BFGS法,基于Kent映射的混沌-BFGS法,MonteCarlo试验-BFGS法,网格-BFGS法进行了研究,分别对3个低维和2个高维非线性复杂测试函数进行优化计算,对它们的全局优化计算效率和寻优能力做了比较,并探讨了混合优化方法全局优化性能差异的原因。结果表明,混沌优化方法是与MonteCarlo方法类似的一种随机性试验优化方法。而且,这类优化方法的计算性能至少与以下因素有关:混沌/随机序列的统计性质,优化问题全局最优点位置。

金属热疲劳的非平衡统计理论研究

从微观机理出发探讨金属热疲劳的宏观统计性质 .利用疲劳断裂非平衡统计理论 ,由 Raj和 Baik的混合模型 ,从微观机理与宏观特性相结合的角度对热疲劳进行分析研究 .得到迁移长大速率、涨落长大系数、热疲劳微裂纹的统计分布和统计平均值、热疲劳断裂概率及可靠性等 ,同时对结果进行了讨论 .结果表明热疲劳微裂纹分布函数、断裂概率。

三稳态Van der Pol-Duffng振子的随机P分岔

分析了乘性和加性噪声作用下三稳态Van der Pol--Duffng振子的随机P分岔.首先用随机平均法得到系统的随机微分方程,求得系统响应幅值的稳态概率密度函数.然后应用分岔分析的奇异性理论,求得随机P分岔发生的临界参数条件,得到多种定性不同的稳态概率密度曲线.讨论了2种激励噪声强度和系统阻尼对响应稳态概率密度曲线峰的个数、各峰值相对大小的影响.通过Monte--Carlo数值模拟对理论计算结果进行了验证.该方法可用于其他系统的随机P分岔分析.

基于高斯混合模型的语音带宽扩展算法的研究

为了降低高带谱失真,研究了带宽扩展算法中特征参数与高带谱包络的互信息和高带谱失真之间的函数关系,并在此基础上提出了一种扩展高斯混合模型带宽扩展算法。首先,算法选择与高带谱包络互信息大的参数构成特征矢量,并根据高斯混合模型计算特征矢量与高带谱包络的联合概率密度。其次,采用Expectation-Maximization(EM)算法估计高斯分量模型参数并计算后验概率。最后,通过后验概率估计高带谱包络。实验结果表明,与传统的高斯混合模型带宽扩展算法相比,本文算法可降低0.3 dB的高带平均谱失真,将谱失真大于10dB的语音帧减少了50%以上。

基于典型样本的信度函数分配的构造方法

D-S证据理论信度函数分配的取值是得到较为准确的融合结果的关键,然而传统方法如采用隶属度函数、正态分布等得到的信度函数分配都具有较大的主观性。为使信度函数分配更具客观性,在总结其它方法的基础上,提出了基于典型样本的信度函数分配构造方法。首先采集各目标模式下的样本,并判断每一模式下的各条证据服从何种概率分布,利用相应的概率公式计算待识别目标模式的各条证据的概率密度,然后进行归一化处理,最后利用联合规则得到融合结果。实例表明利用此法可得到较为准确的融合结果,不仅提高了判别结果的准确性,而且降低了不确定度,并再一次证明了融合诊断结果比单一数据具有更高的可靠性。

贝叶斯判别方法在叠前反演数据解释中的应用

通过开展贝叶斯判别理论在叠前反演数据解释中的应用研究来提高储层预测的准确性。以岩石物理模拟、叠前反演处理和概率密度函数建立作为该技术的关键,基于贝叶斯理论利用测井和岩石物理模拟数据作为先验信息,利用反演成果作为基本数据估计不同岩相的分布概率。该技术充分利用概率和统计作为处理地质不确定性的工具定量解释繁多的叠前反演成果,用这种方法对岩相进行表征和识别,更加适合地质复杂性和多解性特点。火成岩储层预测中的应用表明,贝叶斯判别理论对储层含气性表征更加准确,解决了储层含气性预测难题。

一种考虑失效准则模糊性的时变可靠度分析方法

针对工程结构失效准则不确定性的时变可靠度问题,构造了一种考虑失效准则模糊性的时变可靠度分析方法,可处理模糊失效准则下抗力和荷载随时间变化的可靠性计算问题。该方法首先将模糊失效准则下的时变功能函数随机过程进行离散,然后应用模糊集基本理论,引入新的随机变量,得到不同时间段的等效功能函数,最终将模糊失效准则下的时变可靠性问题转化为常规的可靠性问题,通过一次二阶矩方法求解获得时变可靠度和失效概率。最后以某机械零件和齿轮传动为例,分别得出模糊失效准则下的时变可靠度曲线和失效概率曲线,验证了该方法的有效性。

机械可靠性设计的精确方法──全概率法

目的研究不同应力分布和强度分布组合下的可靠度精确计算方法．方法采用以失效物理和应力－强度干涉理论为基础的全概率法建模，并用数值积分法求解。结果导出了５种分布类型２５种不同组合的应力。强度相干的可靠度计算表达式，实现了威布尔分布３参数（形状参数、尺寸参数、位置参数）和２统计量（均值、标准差）间的可逆转换。结论全概率法是可靠度计算的精确理论解法，它可给出机械产品可靠度的高精度解。

增强操作工况识别可靠性的概率PLS-ELM方法

针对分类阈值任意给定和临近边界区域操作工况识别可靠性低问题,提出基于贝叶斯理论的概率偏最小二乘极限学习机(p-PLS-ELM)分类算法.偏最小二乘被嵌入到极限学习机框架内,通过提取隐含层正交潜在变量,避免共线性引起输出权值系数不稳定,降低输出预报值的不确定性,改善分类编码输出预报模型的鲁棒性和稳定性.应用非线性最小二乘方法估计每类条件概率密度函数的参数,结合概率密度函数和贝叶斯定理,计算每类输出预报值后验概率作为分类可靠性测度.采用该方法在某污水处理厂进行实验验证.实验结果表明,基于概率PLSELM方法的污水处理操作工况识别可靠性和准确性相对优于PLS-ELM方法.

高斯噪声中的参数盲估计

盲信号处理方法中常忽略噪声的影响 ,而实际问题中噪声的影响是存在的 .本文主要讨论了在协方差矩阵未知的加性高斯噪声中混合系数的盲估计问题 .本文以最大似然估计为基础 ,提出一种求解参数的最优化算法 ,给出了混合矩阵和协方差矩阵的计算式 .采用高斯混合模型 (GMM)来逼近源信号的概率密度函数 ,简化了算法中的积分 ,导出了一种基于EM算法的迭代式 .仿真表明 ,算法不仅能稳定收敛 。

面向大数据集的递增聚类方法研究

以往提出的面向大数据集的递增聚类方法直接将多维度的大数据集转换成一维大数据集,导致聚类成果不佳,故提出面向大数据集的递增聚类新方法。为取得高聚类效率,在高度保留原始数据维度的情况下,简化了大数据集递增聚类步骤,构建出大数据处理集合,对集合中的标志样本进行局部递增聚类,将未能成功聚类的大数据平均分配到局部递增聚类结果中,使用高斯概率密度函数和证据理论检测其中的错误坐标并进行改正,获取最终的递增聚类结果。实验结果证明该方法具有优越的聚类成果和聚类效率。