考虑损失厌恶型顾客的产品推荐方法研究

随着电子商务和社交网络的快速发展,在线商品和服务的数量日益增长,顾客越来越难以依据在线信息制定其购买决策。本文基于数据体量较大的在线数值评分,构建产品推荐模型,帮助顾客成功定位所需商品。首先,引入直觉梯形模糊数进行数值评分转换,以处理历史用户给定评分数据的不确定性特征;其次,引入经典前景理论来刻画现实决策过程中顾客的损失厌恶心理。最后,通过汽车之家网站的汽车购买案例及与完全理性顾客推荐结果的对比分析,验证了该模型的实用性和有效性。     

大学数学课程“概率论与数理统计”教学的实践与认识

结合多年教学实践,本文分析了概率论与数理统计课程目前存在的几个主要问题,并对其内容设置、教学方法的改进、应用能力的培养等方面提出了改革的设想.     

高级统计学的教学实践与思考

基于教学实践和调查问卷对研究生高级统计学的各个教学环节进行了探讨和分析.区别于本科生的统计学教育,在研究生的统计教学中,不仅要介绍统计方法,而且还要通过更加有效的手段加强研究生对统计分析方法的整体认识和应用能力.教学实践和对调查问卷的统计分析结果表明:将传统的解释性教学和演示性教学与现代的具有建构主义特征的发现学习相结合将有助于培养研究生的学习能力和科研能力.     

方案集团序方法的进一步研究

从集团序方法出发,探讨了该方法在实际应用中面临的新问题,并将基于相对位置排队的思想引入到集团序中.借助优先关系0-1矩阵,有效地集结了各个不同集团排序方案之间的差异,通过阈值的设定,定义了方案之间的优先关系,进而得到方案间新的排序结果.不仅丰富了集团序的研究成果,也为集团序的进一步研究提供了新的研究空间和研究内容.     

统计决策与贝叶斯分析的实践与思考

统计决策与贝叶斯分析是一门多学科相交叉的边缘课程,具有很强的应用性.本文在对北美一流院校相关课程教学特点的描述和对比分析的基础上,结合我校理工科院校的特色,从教学内容、教学方法和实践教学三个方面系统阐述了我校在该课程教学和课程建设中的几点体会.     

统计在生命科学中的实践与认识(Ⅰ)——生物医学研究与统计的关系

汤旦林，王松柏．统计在生命科学中的实践与认识，数理统计与管理，１９９７，１６（１），６２～６４．生物医学研究和统计的实践与认识互相促进，相辅相成。本文的目的是促进对生物统计的一些基本概念、问题和进展的认识。第一部分，通过回顾一些富有教益的史实，说明统计学和生命科学的实践与认识之间的密切关系，其余部分还将涉及：四格表的“物理”意义和数据处理；两类错误、单双尾检验与单双侧检验；临床试验与调查研究中的问题与进展；对教学方法的思考等     

广西GDP的统计预测模型及其应用

本文利用SPSS统计软件及非参数统计方法(卡方检验和K-S检验法)对广西1950年至2006年共57年的GDP数据进行实证分析.在最佳准则(即AIC准则)下建立了ARIMA(1,2,1)时间序列模型,并利用非参数统计方法对此模型进行了适应性检验,然后利用2001年至2006年的实际值与该模型的预测值进行了比较.最后,本文利用该模型对广西未来五年的GDP进行了预测.     

一份关于初中生统计实践活动的教学实验报告

1问题的提出1.1义务教育阶段统计教学的教育意义和课程目标在义务教育阶段引入"概率统计初步"的理由主要基于两点:"使学生具备处理和解释数据、及根据信息作出判断和决策的能力;使学生能从随机(或统计)的角度来观察世界,面对不确定的情     

多样性解答择优问题的统计对策

随着研究手段的日益丰富,理论研究者和实证研究者越来越倾向于从各个角度分析同一问题,由此会得到不同的研究结论。多样性解答择优就是研究如何从这些不同的解答中找到更合适的解答。本文的研究目的在于探讨多样性解答择优的统计应对策略。从样本自识别建模和评价评委问题出发,本文利用统计方法探讨一类多样性解答择优问题—推广的评委评分问题,并提出了统计对策。     

试用统计方法分析散光与儿童弱视

弱视是一种影响婴幼儿视力的功能性眼病．屈光不正是导致弱视的常见原因之一．尤其是当散光得不到及时正确的矫正时很容易造成弱视．有时散光与可能被误诊为弱视．本文采用了大量临床病历，利用数统计的理论和方法对散光性弱视患儿的弱视程度、患儿的年龄结构及患儿的眼别和性别等关系进行了定量的分析．     

A reassessment of the Global Food Security Index by using a hierarchical data envelopment analysis approach

This study proposes a hierarchical data envelopment analysis (H-DEA) approach to construct a multi-dimensional indicator, and applies it to reassess the 2014 Global Food Security Index created by the Economist Intelligence Unit (EIU) across 110 countries. Instead of using expert opinions to assign weights, the proposed model endogenises the weights, and thus avoids the problems of subjective weighting for international comparisons. The results show that although the ranking is not significantly different from that of the EIU, the optimal scores and weights differ by income levels. Additionally, this work articulates the value of a well-founded performance evaluation method by leveraging experts’ opinions and data-driven techniques through constructing a best-practice frontier with observation-specific weights. It is suggested that food availability should be the top policy priority in low- to medium-income and Sub-Saharan African countries where food deficits are most prevalent. The findings can serve as guidance to improve the design of the ongoing efforts for global food security.     

Human resource allocation applications of stochastic maintenance models with super‐reserve backups

This article deals with stochastic maintenance models that include a repair facility and three types of ‘unreliable’ machines: the main facility of working and reserve machines, and an auxiliary facility of ‘super‐reserve’ machines. Working machines breakdown exponentially and are immediately replaced by available reserve machines. Defective machines line up for repair and refurbished machines are returned to the main facility. This system falls into the category of closed queues with hot standbys and has more options than the basic model. If the main facility is restored to its original quantity and the repair facility leaves on routine maintenance, all reserve machines are temporarily blocked and renewals come from the super‐reserve group until the latter is exhausted. Explicit formulas obtained demonstrate a relatively effortless use of functionals of the main stochastic characteristics, and optimization of their objective function. Human resource applications are included as optimization examples. Copyright © 2005 John Wiley & Sons, Ltd.     

一类未搅拌恒化器中食物网的共存态

本文讨论了一类在单种营养物输入的未搅拌恒化器中的简单食物网模型,该模型除了营养物以外,还包含有一个捕食者种群和两个竞争的食饵种群.应用Dancer不动点指数和度理论的知识,给出了该系统共存态存在的充分必要条件.     

M/G/1非空竭服务休假排队系统随机分解的简化算法

本文根据M／G／1非空竭服务休假排队系统稳态队长随机分解的结构特征提出一种统一算法，该方法简洁高效，避免了再生循环方法繁杂的运算。运用该方法得出的结果与已知的用再生循环方法得出的结论一致。并且修正了Levy(1989)关于Bernoulli闸门服务休假排队系统随机分解的一个错误。     

Statistical Multiplexing of Homogeneous Fractional Brownian Streams

In this paper, the statistical multiplexing of independent fractional Brownian traffic streams with the same Hurst value 0.5<H<1 is studied. The buffer overflow probabilities based on steady-state and transient queue length tail distributions are used respectively as the common performance criterion. Under general conditions, the minimal buffer allocation to the merged traffic is identified in either case so that strictly positive bandwidth savings are realized. Impact of the common H value on multiplexing gains is investigated. The analytical results are applicable in data network engineering problems, where ATM is deployed as the transport network carrying long-range dependent data traffic.     

Loss probability in a finite discrete-time queue in terms of the steady state distribution of an infinite queue

We consider a discrete-time single-server queue with arrivals governed by a stationary Markov chain, where no arrivals are assumed to occur only when the Markov chain is in a particular state. This assumption implies that off-periods in the arrival process are i.i.d. and geometrically distributed. For this queue, we establish the exact relationship between queue length distributions in a finite-buffer queue and the corresponding infinite-buffer queue. With the result, the exact loss probability is obtained in terms of the queue length distribution in the corresponding infinite-buffer queue. Note that this result enables us to compute the loss probability very efficiently, since the queue length distribution in the infinite-buffer queue can be efficiently computed when off-periods are geometrically distributed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Cyclic regenerative method of simulation

In this paper we develop a cyclic regenerative method of simulation. As an example of its application, we consider a single server queuing system with N-control policy of Heyman. Numerical results are presented to illustrate the ability of this method to reduce the variance of the estimate over that of the traditional regenerative method of simulation.     

On number-theoretic method in statistics simulation

Motivated by a random coverage problem from a real-life case study, this paper discusses and compares several number-theoretic methods including the ELP-net, NT-net, and others in statistical simulations. The methods and related conclusions studied in this paper can be extended into more general cases in statistical simulations.     

On the distribution of the number of customers in the symmetric M/G/1 queue

We consider an M/G/1 queue with symmetric service discipline. The class of symmetric service disciplines contains, in particular, the preemptive last-come-first-served discipline and the processor-sharing discipline. It has been conjectured in Kella et al. [1] that the marginal distribution of the queue length at any time is identical for all symmetric disciplines if the queue starts empty. In this paper we show that this conjecture is true if service requirements have an Erlang distribution. We also show by a counterexample, involving the hyperexponential distribution, that the conjecture is generally not true. AMS Subject Classifications Primary—60K25; Secondary—90B22     

一类具有到达损失、可选服务、反馈的M/G/1重试排队系统

考虑一个具有到达损失、可选服务、反馈的M/G/1重试排队系统.在假定重试区域中顾客具有相互独立的指数重试时间的情况下,得到了系统的转移概率矩阵和系统稳态的充分必要条件.列出微分方程,求得稳态时系统队长和重试区域中队长分布及相关指标.