网络团购的定价与收益协调策略研究

如何实现团购网站和团购参与商家之间的双赢是我国网络团购目前面临的一大挑战性问题。结合我国网络团购的特点,构建团购网站和商家之间定价与收益分配的博弈模型,针对博弈结果运用纳什谈判模型给出协调策略。最后,通过数值算例分析主要参数的变化对价格与收益的影响。结果表明,敏感市场的规模和团购网站的广告效应越大、商品的单位成本越小、开展网络团购对商家和团购网站越有利。     

连续区间数的中位算子及其灵敏度分析

研究决策信息以区间数形式给出的方案决策问题。考虑到区间数非均匀分布的特点,为避免区间极端值在区间数确定中产生较大误差,本文将中位数概念运用到区间数的确定上,提出OIP(Ordered Interval Point)有序中位算子。取单位区间单调函数(BUM函数)为二分之一所表示的值为权重,将区间数确定为一个实数,并研究算子单调性和有界性的初等运算性质。通过比较OIP算子与COWA算子对态度参数和区间长度的反应灵敏度,获得了在一定条件下OIP算子对态度参数反应更稳健,对区间长度反应更灵敏的结论。最后用算例证明该算子的可行性和有效性。     

The wavelet multiscale method for inversion of porosity in the fluid-saturated porous media

In this paper, the wavelet multiscale method is applied to the inversion of porosity in the fluid-saturated porous media. The inverse problem is decomposed to multiple scales with wavelet transform and hence the original inverse problem is re-formulated to be a set of sub-inverse problem corresponding to different scales and is solved successively according to the size of scale from the smallest to the largest. On each scale, regularization Gauss–Newton method is carried out, which is stable and fast, until the optimum solution of original inverse problem is found. The results of numerical simulations demonstrate that the method is a widely convergent optimization method and exhibits the advantages of conventional regularization Gauss–Newton method methods on computational efficiency and precision.     

Torsional oscillations in symmetrical structures

A two-time perturbation technique is used to study the lateral and torsional motions of a nonlinear symmetrical structure subject to a lateral sinusoidal ground motion. It is shown that when the ground acceleration frequency is about one-third of or three times the natural frequency of the lateral motion, the symmetrical structure is particularly susceptible to torsional oscillations even when the natural frequency of torsion is not close to the natural frequency of the lateral motion. The implication of this type of nonlinear coupling between the lateral and torsional motions in real structures subject to earthquakes is also discussed.     

Ito过程在免费邮箱硬盘容量动态分配模型中的应用

分析了目前电子邮箱市场的情况,运用微分方程建立了邮箱用户增长模型,预测某邮箱未来几年内的用户数量及企业需要提供的硬盘容量。从减少成本的角度分析,运用Ito随机过程,对风险进行评估,建立硬盘容量动态分配模型,指导企业如何安排合适的硬盘容量,既能满足市场需要,又达到规避风险和降低成本的目的,提高市场竞争力。     

AR（p）模型中的缺失数据估计

运用EM算法,对含有缺失数据的AR（p）模型进行参数估计,通过最大似然准则就非左端缺失的情况进行插补.最后,用蒙特卡洛方法给出实验分析,表明如下结果：（i）误差与AR模型的阶数正相关,与缺失比例正相关;（ii）当AR模型的特征根模长相对较小时,误差与数据长度负相关,且误差被控制在了标准差的30％以内;（iii）当模长中等时,误差基本控制在1个标准差左右;（iv）当模长较大时,误差与数据长度正相关,而且误差也相对较大.     

Optimization of functionals subject to integral constraints

The classical method for optimizing a functional subject to an integral constraint is to introduce the Lagrange multiplier and apply the Euler-Lagrange equations to the augmented integrand. The Lagrange multiplier is a constant whose value is selected such that the integral constraint is satisfied. This value is frequently an eigenvalue of the boundary-value problem and is determined by a trial-and-error procedure. A new approach for solving this isoperimetric problem is presented. The Lagrange multiplier is introduced as a state variable and evaluated simultaneously with the optimum solution. A numerical example is given and is shown to have a large region of convergence.     

Two warehouse inventory models for single vendor multiple retailers with price and stock dependent demand

Here a single vendor multiple retailer inventory model of an item is developed where demand of the item at every retailer is linearly dependent on stock and inversely on some powers of selling price. Item is produced by the vendor and is distributed to the retailers following basic period policy. According to this policy item is replenished to the retailers at a regular time interval (T₁) called basic period (BP) and replenishment quantity is sufficient to last for the period T₁. Due to the scarcity of storage space at market places, every retailer uses a showroom at the market place and a warehouse to store the item, little away from the market place. Item is sold from the showroom and is filled up from the warehouse in a bulk release pattern. Some of the inventory parameters are considered as fuzzy in nature and model is formulated to maximize the average profit from the whole system. Imprecise objective is transformed to equivalent deterministic ones using possibility/necessity measure of fuzzy events with some degree of optimism/pessimism. A genetic algorithm (GA) is developed with roulette wheel selection, arithmetic crossover and random mutation and is used to solve the model. In some complex cases, with the help of above GA, fuzzy simulation process is used to derive the optimal decision. The model is illustrated through numerical examples and some sensitivity analyses are presented.     

带有潜伏期的狂犬病模型及控制策略研究

研究建立了狗与人两个群体的SEIR狂犬病模型,把狂犬病潜伏期阶段的传染性加入到模型中,利用遗传算法对1996年到2015年的数据进行拟合,估出了中国狂犬病的基本再生数R0≈1.66,证明了狂犬病无病平衡点的全局稳定性以及模型的一致持续性.根据数值模拟结果,发现处于潜伏期的犬类对人类狂犬病造成威胁.因此控制狂犬病的一个关键措施就是要做好犬的管理,减少与犬只的接触,这对抑制狂犬病的爆发有着重要的作用,也为我国狂犬病的控制提供了可靠的理论依据.     

Analysis of cyclic queueing networks with parallelism and vacation

The aim of this paper is to improve the machine interference model with vacation to deal with more recent problems of the communication area. To this scope the model is extended to include parallelism in the vacation station. The underlying Markov process is analyzed and a state arrangement is found that yields an efficient matrix-analytic technique that substantially lowers down the time- and space-complexity of standard methods. A numerical example of the method effectiveness is presented, and an example of resource allocation is introduced that finds applications in the QoS management of wireless networks. The author is thankful to the anonymous referees for the improvements their comments have earned to the quality of the presentation and to the completeness of the paper. The author is thankful to Giuseppe Iazeolla, whose careful reading of the original draft of this paper led to significant improvements in its overall quality. This work was partially supported by funds from the FIRB project “Performance Evaluation of Complex Systems: Techniques Methodologies and Tools” and by the University of Roma TorVergata project on High Performance ICT Platforms.     

基于熵的群决策专家选择研究

群决策是研究多人如何做出统一的有效抉择.在群决策中专家决策水平直接反应到决策结论上,是影响事业的成败关键,因此专家的选择对于群决策而言是至关重要的.建立了评价群决策专家的指标集,从专家选择角度定义了理想专家,给出了专家选择的熵模型,并通过一个例子说明该模型的有效性.     

A defense of indeterminism

My goal is to defend the indeterminist approach to vagueness, according to which a borderline vague utterance is neither true nor false. Indeterminism appears to contradict bivalence and the disquotational schema for truth. I agree that indeterminism compels us to modify each of these principles. Kit Fine has defended indeterminism by claiming that ordinary ambiguous sentences are neither true nor false when one disambiguation is true and the other is false. But even if Fine is right about sentences, his point does not seem to generalize to utterances. What the indeterminist needs -- and what ordinary ambiguity does not provide -- is an ambiguous utterance where what is being said is indeterminate between two different propositions. I will show that such cases exist. These cases imply that the modifications that indeterminism makes to bivalence and the disquotational schema are required independently of indeterminism, in fact independently of vagueness.     

一种改进的蚁群算法及其在TSP中的应用

蚁群算法是一种求解复杂组合优化问题的新的拟生态算法,也是一种基于种群的启发式仿生进化算法,属于随机搜索算法的一种,并用于较好地解决TSP问题.然而此算法也有它自己的缺陷,如易于陷入局部优化、搜索时间长等.通过对基本蚁群算法的介绍及相关因素的分析,提出了一种改进的蚁群算法,用于解决TSPLAB问题的10个问题,并与参考文献中的F-W、NCSOM、ASOM算法进行比较,计算机仿真结果表明了改进算法的有效性.如利用改进的蚁群算法解决lin105问题,其最优解为14382.995933(已知最优解为14379),相对误差是0.0209%,计算出的最小值几乎接近于已知最优解.     

基于区间数贴近度的不确定多属性决策模型

针对只有部分权重信息且属性值以区间数形式给出的多属性决策问题,提出了一种基于区间数贴近度的决策方法.首先讨论了区间数贴近度的定义和性质;然后给出了解决不确定多属性决策问题的一般步骤.并依据传统的逼近理想解的基本思路,以实际评价值与理想解之间的贴近度最大化为目标建立优化模型,从而得到指标权重.进而计算出每个方案与正理想解的相对贴近度,即可得到所有方案的排序结果.方法能充分利用规范化评价的先验信息,评价结果客观可靠,不具有主观随意性.最后通过实例分析验证了该方法的有效性和实用性.     

Dual row modules and polyhedra of blocking group problems

Corresponding to every group problem is a row module. Duality for group problems is developed using the duality or orthogonality of the corresponding row modules. The row module corresponding to a group problem is shown to include Gomory's fractional cuts for the group polyhedron and all the vertices of the polyhedron of the blocking group problem. The polyhedra corresponding to a pair of blocking group problems are shown to have a blocking nature i.e. the vertices of one include some of the facets of the other and mutatis mutandis. The entire development is constructive. The notions of contraction, deletion, expansion and extension are defined constructively and related to homomorphic liftings and suproblems in a dual setting. Roughly speaking a homomorphic lifting is dual to forming a subproblem. A proof of the Gastou-Johnson generalization of Gomory's homomorphic lifting theorem is given, and dual constructions are discussed. A generalization of Gomory's subadditive characterization to subproblems is given. In the binary case, it is closely related to the work of Seymour on cones arising from binary matroids.     

基于模糊数的模糊事件概率的结构元表示

Zadeh[1]定义了在概率清晰和事件模糊条件下,模糊事件的概率表示.不过,用[1]表示概率,求解繁杂且困难.为此,利用结构元理论,定义了模糊数事件概率的表达式.不仅证明其与经典定义等价,且证明了模糊数事件复合表达形式.最后,给出了关于模糊数不等式的概率的表达式.通过算倒可看出,运用本方法求解模糊数事件概率比较简捷.     

Self-triggered filter design for a class of nonlinear stochastic systems with Markovian jumping parameters

This paper is concerned with the self-triggered filtering problem for a class of Markovian jumping nonlinear stochastic systems. The event-triggered mechanism (ETM) is employed between the sensor and the filter to reduce unnecessary measurement transmission. Governed by the ETM, the measurement is transmitted to the filter as long as a predefined condition is satisfied. The purpose of the addressed problem is to synthesize a filter such that the dynamics of the filtering error is bounded in probability (BIP). A sufficient condition is first given to ensure the boundedness in probability of the filtering error dynamics, and the characterization of the desired filter gains is then realized by means of the feasibility of certain matrix inequalities. Furthermore, a self-triggered mechanism is designed to guarantee the filtering error dynamics to be BSP with excluded Zeno phenomenon. In the end, numerical simulation is carried out to illustrate the usefulness of the proposed self-triggered filtering algorithm.     

直觉模糊模型检测在工程决策上的应用

将直觉模糊Kripke结构扩展到加权直觉模糊Kripke结构,将直觉模糊计算树逻辑诱导到加权直觉模糊计算树逻辑;研究在此之上的直觉模糊期望测度和多属性工程决策问题。用加权直觉模糊Kripke结构的权值自然地刻画了工程问题中的成本和收益,直觉模糊测度量化工程进展的不确定性,用加权直觉模糊计算树逻辑描述不确定性工程属性约束。给出了基于直觉模糊模型检测的多属性工程寻优算法,并讨论了算法的复杂度。     

页岩气区块优选的模糊动态多属性决策模型研究

页岩气作为目前最现实的可替代能源倍受各国政府和企业的高度关注。针对信息不确定下页岩气区块优选的动态多属性决策难题,在初步估测不同阶段地质资源禀赋、基础设施建设投资以及环境保护要求等不确定信息下,以优选具有商业化价值开发的页岩气目标区块为重点研究对象,从解决不同区块的投资优先次序入手,运用多属性决策、模糊优化决策和动态决策优化的方法理论,通过剖析页岩气区块优选决策过程及其复杂性特征,将页岩气区块投资优选和排序问题进行形式化描述,提出一种探索解决这种模糊动态多属性决策问题的方法,并应用到具体的页岩气区块优选问题中。本项研究不仅有助于深化不确定条件下动态多属性决策理论的研究,还为解决页岩气区块优选这一投资决策难题提供新的思路和方法。     

精确覆盖问题的加权分治算法

精确覆盖问题是组合优化中经典的NP-Hard问题之一,其在诸多领域具有广泛的应用价值。本文首先研究了精确覆盖问题的数学性质,并根据数学性质提出相应的分支降阶规则以缩小问题的规模;接着设计了一个基于分支降阶的回溯算法求解该问题;然后运用常规技术分析得出该精确算法的时间复杂度为O(1.4656^k);最后运用加权分治技术对该算法的时间复杂度进行分析,将该算法的时间复杂度降为O(1.3842^k)。文章最后通过一个示例进一步阐述该算法的原理,并与其他精确算法进行了对比分析,研究结果表明该算法是可行的,也是有效的。