选区划分模型及快速分类算法

本文主要研究选区重新划分问题.利用公平性原则和广度优先搜索方法,获得一个选区划分模型和一个求解该模型的定向目标算法.理论分析和数值计算结果表明模型设计合理,算法切实可行.     

图的导出森林2-划分

对一个给定的简单图Ｇ，是否存在Ｖ（Ｇ）的一个２－划分（Ｖ１，Ｖ２）使得每个导出子图Ｇ［Ｖｉ］为森林？称该问题为导出森林２－划分问题．本文证明了对最大度为５的图该问题是ＮＰ－完全的，而对最大度≤４的图该问题多项式时间可解．     

最小最大树划分的近似算法与最小和树划分的精确算法

本文研究把连通赋权图的点集划分成p个子集,要求每个点子集的导出子图都连通,并且使得所得到的p个子图的最小支撑树中权重最大者的权重达到最小(最小最大树划分问题),或者使得所得到的p个子图的最小支撑树权重之和达到最小(最小和树划分问题)．文中给出了最小最大树划分问题的强NP困难性证明,并给出了一个多项式时间算法,该算法是最小最大树划分问题的竞争比为p的近似算法,同时是最小和树划分问题的精确算法．     

模糊聚类最优划分判定的一种新模型

针对聚类分析的模糊模式未解决的问题:模糊划分空间中模糊最优划分的判定问题,提出一个新的判定模型。给出基于新的最优划分判定模型的应用例子,验证了模型算法应用的可行性。     

矿井瓦斯抽放效果的灰色聚类评估

为了对矿井瓦斯抽放效果进行合理评估,通过将中心点三角白化权函数中对应于两端灰类的白化权函数分别划分为下限测度白化权函数和上限测度白化权函数,构建矿井瓦斯抽放效果评估模型,并利用模型对矿井重点位置的瓦斯浓度值进行评估、诊断.模型计算结果表明,改进的中心点白化权函数评估模型可以确保各灰类聚类系数之和为1,而且在划分瓦斯抽放效果的灰类时较中心点三角白化权函数评估模型更为准确.     

基于改进目标函数聚类法的模糊最优划分判定模型

针对聚类分析的Fuzzy模式未解决的问题:模糊划分空间中模糊最优划分的判定问题,以改进的目标函数聚类法为基础,建立与定义指标集对应的模糊最优划分判定模型,求解最优划分矩阵.     

一种连续的谱聚类优化模型

聚类与图的划分问题在大数据分析中有着重要的应用.这类问题一般被描述为组合优化问题,因此较难快速求解.本文设计了一种新的连续优化模型,并提出了一种块坐标下降算法,数值实验显示我们的新方法在求解聚类与图的划分问题上很有潜力.我们还更进一步分析了我们的连续优化模型和组合优化模型的关系.     

自然数划分中两类非通项约束

自然数划分中两类非通项约束娄惠元，那履弘（沈阳黄金学院，１１００１５）关键词自然数，划分，约束．分类号ＡＭＳ（１９９１）１１Ｐ８１／ＣＣＬＯ１５６．４自然数ｎ划分为ｍ个自然数之和是指将ｎ表示为ｎ＝ｎ＿１＋ｎ＿２＋…＋ｎ＿ｍ的形式，其中ｎ＿１，…，ｎ＿...     

自然数划分中一种新约束

自然数划分中一种新约束那履弘，娄惠元（沈阳黄金学院，１１００１５）自然数ｎ分为ｍ个部分的一个划分的定义是ｎ的一种形如ｎ＝ｎ＿１＋ｎ＿２＋…ｎ＿ｍ的表示，其中自然数ｎ＿ｉ满足ｎ＿１≥ｎ＿２≥…≥ｎ＿ｍ≥１．由划分给出的ｎ＿１，…，ｎ＿ｍ称为项。我们用Ｐ...     

基于平滑扩充原理的商业银行信用风险评级模型及实证

本文通过银行的资产质量方面、资本充足率方面、管控效能层面、盈利状态层面、流动性层面与社会敏感度层面等构建商业银行信用风险评价体系。根据平滑扩充原理模拟生成大样本数据,对评级得分进行扩充,进而根据扩充后的大样本数据划分银行的信用风险等级。解决了由于样本少、无法对信用等级合理划分的难题。通过实证分析可以了解到,本文得出的银行评级信息和标准普尔提供的评价结论存在共同的序关系状态。因此,可根据本模型对大多数未经过国际权威机构评级的银行进行风险评级。     

Replica Symmetry Breaking in an Axial Model of Quadrupolar Glass

We investigate the replica symmetry breaking (RSB) in a neighborhood of the instability point of the replica-symmetric solution in the axial quadrupolar glass model. We show that the solution with the first-stage RSB is stable against the subsequent RSB. Although there is no reflection symmetry, the first-stage RSB solution continuously bifurcates from the replica-symmetric one. This implies that our model does not belong to either of the two classes into which spin glasses are usually divided.     

A Simple Cluster Model for the Liquid–Glass Transition

Using the classical distribution-function approach to simple liquids, we estimate the orientational interaction between clusters consisting of a particle and its nearest neighbors. We show that there are density and temperature ranges where the interaction changes sign as a function of the cluster radius. On this basis, the corresponding model of interacting cubic and icosahedral clusters (of the type of a spin glass model) is proposed and solved in the replica-symmetric approximation. We show that the glass order parameter grows continuously on cooling and the replica-symmetry-breaking temperature can be identified with the glass transition temperature. We also show that on cooling a system of particles with a Lennard-Jones interaction, cubic clusters freeze first. The transition temperature for icosahedral clusters is somewhat lower; therefore, the cubic structure of the short-range order is more likely in a Lennard-Jones glass near transition.     

玻壳成型过程诱导残余应力的数值预测

建立了玻壳压制成型固化过程中残余应力预测的数值模拟模型,采用平行平板间玻璃熔体的固化问题来描述成型过程中残余应力形成的机理,并假定材料为热流变简单粘弹性材料．基于板壳理论,将产品视为平板单元的组合,并采用有限元法来求解,这种方法可以象全三维计算一样一层层地计算残余应力,非常适合复杂形状的薄压制成型产品．最后通过实验比较验证了所提出的模型和方法．     

Spin-glass-type state in complex nonmagnetic systems

We briefly review our works concerned with generalized models of spin glass, which describe a wide class of glasses (multipole systems, real cluster glasses, and others). We consider several new models and discuss how the scenario of glass transition depends on different factors. We propose a classification of the behaviors of complex spin glasses depending on the system symmetry properties.     

Orientation ordering and the transition to the orientational glass state in fullerite C<Subscript>60</Subscript>

We propose a model for describing the low-temperature transition to the orientational glass state in solid molecular C₆₀ in the framework of a theory similar to spin glass theory. We find a replica symmetric solution and also break the replica symmetry. The obtained results agree with experimental data on the partial retention of the orientational long-range order in the glass phase and on the presence of a broad maximum on the curve corresponding to the temperature dependence of the orientational part of the heat capacity. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 155, No. 2, pp. 356–368, May, 2008.     

Ultrametricity of the state space in glasses

We review the results related to the ultrametricity notion in glasses. We present the proof of the ultrametricity of the replica space for an arbitrary spin glass model with reflection symmetry. We solve the problem of describing the dynamics of a system with an ultrametric state space using the Keldysh functional method for nonequilibrium dynamics in which the quasinonergodicity of the system is taken into account by introducing a hierarchical spectrum of relaxation times.     

Kinetics of glass transition and crystallization in multicomponent bulk amorphous alloys

Differential scanning calorimeter (DSC) is used to investigate apparent activation energy of glass transition and crystallization of Zr-based bulk amorphous alloys by Kissinger equation under non-isothermal condition. It is shown that the glass transition behavior as well as crystallization reaction depends on the heating rate and has a characteristic of kinetic effects. After being isothermally annealed near glass transition temperature, the apparent activation energy of glass transition increases and the apparent activation energy of crystallization reaction decreases. However, the kinetic effects are independent of the pre-annealing.     

Soft-mode related origin of the boson peak and acoustic-phonon broadening in glasses

We study the origin of the boson peak and an associated mechanism for acoustic-phonon broadening (below the peak) in glasses exhibiting a high-frequency sound above the peak. The origin is related to the Ioffe-Regel crossover for inelastic (resonant) scattering of acoustic phonons from harmonic soft-mode vibrations. The broadening mechanism is due to the resonant interaction of a harmonic soft-mode vibration with acoustic phonons, which results in the resonant scattering. We find that the associated width of the phonon is independent of temperature and is characterized by a power-law frequency dependence with the exponent varying from ϰ=2 just below the boson peak to ϰ=4 at lower frequencies. The dependences seem to partly agree with some recent experimental data for the glasses under consideration. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 154, No. 1, pp. 77–90, January, 2008.     

Random overlap structures: properties and applications to spin glasses

Random overlap structures (ROSt’s) are random elements on the space of probability measures on the unit ball of a Hilbert space, where two measures are identified if they differ by an isometry. In spin glasses, they arise as natural limits of Gibbs measures under the appropriate algebra of functions. We prove that the so called ‘cavity mapping’ on the space of ROSt’s is continuous, leading to a proof of the stochastic stability conjecture for the limiting Gibbs measures of a large class of spin glass models. Similar arguments yield the proofs of a number of other properties of ROSt’s that may be useful in future attempts at proving the ultrametricity conjecture. Lastly, assuming that the ultrametricity conjecture holds, the setup yields a constructive proof of the Parisi formula for the free energy of the Sherrington–Kirkpatrick model by making rigorous a heuristic of Aizenman, Sims and Starr.     

Description of the paramagnet-spin glass transition in the Edwards-Anderson model using critical-dynamics methods

We show that the paramagnet-spin glass transition can be described in the Edwards-Anderson model using critical-dynamics methods and taking the ultrametric topology of the temporal space into account. In the framework of the suggested approach, we derive the Vogel-Fulcher relation for the system relaxation time. We prove that the fluctuation-dissipation theorem holds for the given model if there is no relaxation-time hierarchy. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 147, No. 2, pp. 328–336, May, 2006.