On subtractive varieties II: General properties

As a sequel to [23] we investigate ideal properties focusing on subtractive varieties. After having listed a few basic results, we give several characterizations of the commutator of ideals and prove, for example, that it commutes with finite direct products. We deal with the ideal extension property (IEP) and with related commutator properties, showing for instance that IEP implies that the commutator commutes with restriction to subalgebras. Then we characterize varieties with distributive ideal lattices and relate this property with (a form of) equationally definable principal ideals and with IEP. Then, at the other extreme, we deal with Abelian and Hamiltonian properties (of ideals and congruences), giving for example a purely ideal theoretic characterization of varieties of Abelian groups with linear operations. To finish with, we present a few examples aiming at vindicating our work.Presented by A. F. Pixley.     

Sampling with a String

Kramer's sampling theorem forms a bridge between the Whittaker-Shannon-Kotel'nikov sampling theorem and boundary-value problems. It has been shown that sampling expansions associated with Sturm-Liouville boundary-value problems are Lagrange-type sampling series, i.e., Lagrange series with infinitely many terms converging to entire functions. String theory as developed by Feller, Kac, and Krein, is a generalization of the Sturm-Liouville theory. We investigate sampling series associated with strings and compare them with those associated with Sturm-Liouville problems. We show that unlike sampling series associated with Sturm-Liouville problems, those associated with strings include not only Lagrange-type sampling series, but also Lagrange polynomial interpolation.     

大密度比和大压力比可压缩流的数值计算

将WENO方法、RKDG方法、RKDG方法结合原来的Ghost Fluid方法以及RKDG方法结合改进的Ghost Fluid方法,应用到大密度比和大压力比的单相流以及气-气、气-液两相流的数值计算,并对计算结果进行了比较分析．结果表明,与其它的方法相比,RKDG方法结合改进的Ghost Fluid方法得到了高分辨率的计算结果,可以捕捉到正确的激波位置,随着网格的加密,计算解收敛到物理解．     

Homeomorphs and amallamorphs of the Petersen graph

Let P be the Petersen graph. The main results of this paper are the discovery of infinite families of chromatically equivalent pairs of P homeomorphs and the discovery of infinite families of flow equivalent pairs of P amallamorphs. In particular, three families of P homeomorphs with 8 parameters, five families with 7 parameters and many families with fewer parameters are obtained. Also one family of P amallamorphs with 9 parameters, three families with 7 parameters, seven families with 6 parameters and many families with fewer parameters are obtained.     

拉伸偏心椭圆孔板的应力集中系数表达式

先用半解析半经验的方法推导出拉伸中心椭圆孔有限宽板应力集中系数的显式表达式．将其计算结果和Durelli的光弹性实验结果、Isida公式以及有限元分析结果比较可知,新推导公式的精度较高,且适用范围更广．再用类似的方法推导出拉伸偏心椭圆孔板应力集中系数的显式表达式．经与Isida的公式和有限元分析结果比较可知,该公式适用范围更广、精度更高．当偏心距在一定范围内,误差小于8%．根据应力集中系数与应力强度因子的关系,由已得到的应力集中系数得出拉伸中心裂纹有限宽板和拉伸偏心裂纹板的应力强度因子．经与已有公式以及有限元分析结果比较可知,该应力强度因子表达式也有足够的精度．     

The lattice of convex subgroupoids of an ordered groupoid

Let V(A) (V_o (A)) be the lattice consisting of ϕ and all convex subgroupoids (with zero) of an o-groupoid A (with zero) with respect to the union B∨C which is the convex subgroupoid generated by B∩C and the set-theoretical intersection. In this paper, we study partially ordered groupoids (o-groupoids with zero) without proper convex subgroupoids (with zero), o-groupoids (with zero) for which V(A) (V_o (A)) is a chain, is the Cartesian product of two chains, is modular, is distributive, is complemented, or has a finite length, and also o-groupoids with zero and with associative powers (o-semigroups) in which every subgroupoid with zero (sub-semigroup) is convex. Finally, we give some results about lattice-closed classes of o-groupoids.     

A one‐dimensional computational model for hyperelastic string structures with Coulomb friction

In this paper, we consider a new model for the simulation of textiles with frictional contact between fibers and no bending resistance. In the model, one‐dimensional hyperelasticity and the Capstan equation are combined, and its connection with conventional hyperelasticity and Coulomb friction models is shown. Then, the model is formulated as a problem with the rate‐independent dissipation, and we prove that the problem possesses proper convexity and continuity properties. The article concludes with a numerical algorithm and provides numerical experiments along with a comparison of the results with a real measurement. Copyright © 2016 John Wiley & Sons, Ltd.     

一种资源投入不确定情形下的合作博弈形式及收益分配策略

首先,将经典合作博弈进行扩展,提出了一类模糊联盟合作博弈的通用形式,涵盖常见三种模糊联盟合作博弈,即多线性扩展博弈、比例模糊博弈与Choquet积分模糊博弈.比例模糊博弈、Choquet积分模糊博弈的Shapley值均可以作为一种特定形式下模糊联盟合作博弈的收益分配策略,但是对于多线性扩展博弈的Shapley值一直关注较少,因此利用经典Shapley值构造出多线性扩展博弈的Shapley值,以此作为一种收益分配策略.最后,通过实例分析了常见三类模糊联盟合作博弈的形式及其对应的分配策略,分析收益最大的模糊联盟合作对策形式及最优分配策略,为不确定情形下的合作问题提供了一定的收益分配依据.     

Manifolds with Cusps

In this paper manifolds with cusps are defined and their properties investigated. Manifolds with cusps are manifolds with boundary where the dimension of the tangent cone at points varies widely with that point. Examples are exponential sums, splines, and polynomials with only real roots. The investigations are motivated by numerical algorithms in approximation theory and other areas.     

变厚度圆薄板非对称非线性弯曲问题

首先将直角坐标系中的横向变厚度薄板的大挠度方程,转化到极坐标系中的变厚度圆薄板的非对称大挠度方程·　此方程和极坐标系中径向、切向两个平衡方程联立求解·　将物理方程和中面应变非线性变形方程,代入3个平衡方程,可得用3个变形位移表示的3个非对称非线性方程·　用Fourier级数表示的解代入基本方程,获得相应的基本方程·　在周边夹紧边界条件下,用修正迭代法求解·　作为算例,研究了余弦形式载荷作用下的问题,还给出了载荷与挠度的特征曲线,曲线依据变厚度参数变化而变化,其结果和物理概念完全吻合·     

Differential equations on manifolds with edge singularities in spaces with asymptotics

The present paper deals with differential equations with edge degeneration in spaces with asymptotics. We give the definition of an edge space with asymptotics, prove the continuity of operators with edge degeneration in the scale of these spaces, present statements of problems with edge operators, and state conditions providing their Fredholm property.     

On the existence,uniqueness and stability of periodic solutions of large scale systems with unbounded delay

In this paper, we consider the periodic solution problems for the systems with unbounded delay, and the existence, uniqueness and stability of the periodic solution are dealt with unitedly. First we establish the suitable delay-differential inequality, then study seperately the problems of periodic solution for the systems with bounded delay, with unbounded delay and the Volterra integral-differential systems with infinite delay by using the character of matrix measure and the asymptotic fixed point theorem of poincaré's periodic operator in the dfferent phase spaces. A series of simple criteria for the existence, uniqueness and stability of these systems are obtained.     

居民消费的习惯形成与实际经济周期模型的求解分析——一个基于三部门RBC模型的研究

结合H-P滤波法和King,Plosser&.Robelo(1987)的研究,探讨了一个求解引入居民消费的习惯形成和存在稳态趋势增长的RBC模型的对数线性化方法,并利用该方法求解引入习惯形成和政府支出冲击的三部门RBC模型来分析中国1979-2009年间宏观经济波动.研究表明:这个方法求解本文模型的预测结果与中国的特征事实较一致;与NHG方法求解的预测结果相比较,二者存在明显的差异;对中国经济的解释力要强于NHG方法求解的预测结果.     

Complete classification of spatial surfaces with parallel mean curvature vector in arbitrary non-flat pseudo-Riemannian space forms

Submanifolds with parallel mean curvature vector play important roles in differential geometry, theory of harmonic maps as well as in physics. Spatial surfaces in 4D Lorentzian space forms with parallel mean curvature vector were classified by B. Y. Chen and J. Van der Veken in [9]. Recently, spatial surfaces with parallel mean curvature vector in arbitrary pseudo-Euclidean spaces are also classified in [7]. In this article, we classify spatial surfaces with parallel mean curvature vector in pseudo-Riemannian spheres and pseudo-hyperbolic spaces with arbitrary codimension and arbitrary index. Consequently, we achieve the complete classification of spatial surfaces with parallel mean curvature vector in all pseudo-Riemannian space forms. As an immediate by-product, we obtain the complete classifications of spatial surfaces with parallel mean curvature vector in arbitrary Lorentzian space forms.      

附加非线性振子的双稳态电磁式振动能量捕获器动力学特性研究

随着微机电科技的进步,利用环境振动进行系统自供电已经成为目前非线性动力学研究的热点.将质量-弹簧-阻尼系统与双稳态振动能量捕获系统相结合,提出了附加非线性振子的双稳态电磁式振动能量捕获器,建立系统的力学模型及控制方程.通过数值仿真研究了简谐激励下质量比和调频比发生变化时附加非线性振子的双稳态电磁式振动能量捕获器的动力学响应.通过与附加线性振子双稳态系统的对比,获得了上述参数对附加非线性振子的双稳态电磁式振动能量捕获器发生大幅运动的影响规律,显示出附加非线性振子的双稳态电磁式振动能量捕获器的优越性,并获得了附加非线性振子的双稳态电磁式振动能量捕获器发生连续大幅混沌运动的最优参数配合.上述研究结果为双稳态电磁式振动能量捕获系统的相关研究提供了理论基础.     

Infectious disease models with time-varying parameters and general nonlinear incidence rate

Infectious disease models with time-varying parameters and general nonlinear incidence rates are analyzed. The functional form of the nonlinear incidence rate is assumed to change in time, due to, for example, environmental factors or a change in population behavior. More specifically, a new SIR model with time-varying parameters and switched nonlinear incidence rate is studied. The stability of the disease-free equilibrium is investigated, as well as disease persistence in the endemic case. A switched epidemic model with generalized compartments and time-varying parameters is also proposed and analyzed. Pulse vaccination and pulse treatment are applied to the new SIR model with seasonality and switched incidence rate. A control strategy with vaccine failure is applied to the switched epidemic model with generalized compartments. The control strategies are analyzed to determine their success in eradicating the disease. Some examples are given, with simulations, to illustrate the threshold conditions found.     

半环中带算子的L-模糊h-理想

The notions of M-hemirings and L-fuzzy left h-ideals with operators in M-hemirings are introduced,and some properties are investigated.Given an L-fuzzy left h-ideal with operators,a new L-fuzzy left h-ideal with operators is established. Using a collection of left M-h-ideals,L-fuzzy left h-ideais with operators are con- structed.Moreover,the concept of M-Notherian M-hemiring is introduced and its characterization is given.     

Balanced contributions for TU games with awards and applications

Calleja et al. [Calleja, P., Borm, P., Hendrickx, R., 2005. Multi-issue allocation situations. European Journal of Operational Research 164, 730–747] introduced multi-issue allocation situations with awards. In this paper, we extend the classical model of cooperative games with transferable utility to the cooperative games with transferable utility and awards. We define a run-to-the-bank rule for cooperative games with transferable utility and awards and characterise it in terms of a property of balanced contributions. We apply our main result to bankruptcy problems and multi-issue allocation situations with awards.     

带两个服务等级的三台机最优在线算法

研究了带服务等级约束的三台平行机在线排序问题.每台机器和每个工件的服务等级为1或者2,工件只能在等级不高于它的机器上加工,即等级为1的工件只能在等级为1的机器上加工,等级为2的工件可在所有机器上加工.每个工件的加工时间为一个单位,目标是极小化所有工件的总完工时间.考虑两种情形:当一台机器等级为1,两台机器等级为2时,给出了竞争比为17/14的最优在线算法;当两台机器等级为1,一台机器等级为2时,给出了竞争比为43/36的最优在线算法.