Identification of Influential Cases in Kernel Fisher Discriminant Analysis

We study the influence of a single data case on the results of a statistical analysis. This problem has been addressed in several articles for linear discriminant analysis (LDA). Kernel Fisher discriminant analysis (KFDA) is a kernel based extension of LDA. In this article, we study the effect of atypical data points on KFDA and develop criteria for identification of cases having a detrimental effect on the classification performance of the KFDA classifier. We find that the criteria are successful in identifying cases whose omission from the training data prior to obtaining the KFDA classifier results in reduced error rates.     

Statistical Analysis of Coins Lost in Circulation

The loss rate of coins in the Israeli pound (IL) series issued in Israel in 1960–1979 is estimated, and the connection between it and the characteristics of the coins is examined. A lifetime model with time-dependent hazard rate and an estimation procedure for the model parameters are presented. The estimates are then used to forecast the number of coins surviving in circulation and the median lifetime of different denominations. The data are random samples drawn from the coins in circulation at a point in time, the sampled coins being sorted by date of issue.     

我国主要产业之间合作竞争关系的实证分析

利用文①中所述方法和我国6产业的历史数据,建立了我国6产业的线性动力系统模型.利用这个线性动力系统模型,分析了我国6个产业之间的合作竞争关系,各产业对国民经济发展速度的影响,及产业比例结构的时间演化特征.分析显示,在现阶段,建筑业每单位产值将使GDP每年增加11.71单位;交通邮电通信业,每单位产值将使GDP每年增加6.83单位.这意味着建筑业、交通邮电通信业的发展,将显著地提高国民经济的发展速度.     

A Retrial Queue with a Constant Retrial Rate,Server Downs and Impatient Customers

ABSTRACT

In this paper, we consider a retrial queueing system consisting of a waiting line of infinite capacity in front of a single server subject to breakdowns. A customer upon arrival may join the queue (waiting line) or go to the retrial orbit (another queue) to retry for service after a random time. Only the customer at the head of the retrial orbit is allowed to retry for service. Upon retrial, the customer enters the service if the server is idle; otherwise, it may go back to the retrial orbit or leave the system (become impatient). All the interarrival times, service times, server up times, server down times and retrial times are exponential, and all the necessary independence conditions in these variables are assumed. For this system, we provide sufficient conditions under which, for any given number of customers in the orbit, the stationary probability of the number of customers in the waiting line decays geometrically. We also provide explicitly an expression for the decay parameter.     

中国城市化发展进程及展望

中国的城市化在改革开放后步入了平稳发展期,遵循城市化逻辑增长模型,利用1973-2008年的数据进行估计后得出:中国城市化年均增长速度为0.0412,远远快于0.01729的世界平均水平;2014年左右,中国将结束高速城市化过程,此时的城市化率将达50.11%;中国城市化的饱和值约为84.98%,而67%左右可能是中国未来20年城市化发展的顶部,此后城市化水平会在一个较长的时期维持在70%左右。     

哲学思维与自然信念之间的张力——王阳明“山中观花问答”新论

心物关系问题在阳明哲学中至关重要,解答该问题的经典案例是＂山中观花问答＂。该问答的＂问＂,问出了哲学思维和自然信念之间的张力;该问答的＂答＂,答出了心物＂同寂同感＂、＂一气流通＂、＂同有同无＂的意向性结构特征。意向性结构是理解＂心外无物＂之哲学命题与＂有物与心无关＂之自然信念并使二者达成和解的关键。     

SOJOURN TIMES IN NON-HOMOGENEOUS QBD PROCESSES WITH PROCESSOR SHARING

We study sojourn times of customers in a processor sharing queue with a service rate that varies over time, depending on the number of customers and on the state of a random environment. An explicit expression is derived for the Laplace–Stieltjes transform of the sojourn time conditional on the state upon arrival and the amount of work brought into the system. Particular attention is paid to the conditional mean sojourn time of a customer as a function of his required amount of work, and we establish the existence of an asymptote as the amount of work tends to infinity. The method of random time change is then extended to include the possibility of a varying service rate. By means of this method, we explain the well-established proportionality between the conditional mean sojourn time and required amount of work in processor sharing queues without random environment. Based on numerical experiments, we propose an approximation for the conditional mean sojourn time. Although first presented for exponentially distributed service requirements, the analysis is shown to extend to phase-type services. The service discipline of discriminatory processor sharing is also shown to fall within the framework.     

通风与空调工程漏风量测试装置的改进

风管漏风量的大小是检验通风与空调系统工程质量和降低能耗的一项重要指标，以“通风与空调工程施工及验收规范GB50243－97”的一项新增条款为依据，对漏风量测试装置作了分析，着重对以孔板作节流元件的风管式漏风测试装置在风压调整及自动取压两方面作了改进，并做了相应的试验，为新规范在行业内的实施与推广作必要的准备。     

供给因素、结构变化、汇率与中国的机电产品贸易

基于考虑供给因素、结构变化的出口决定模型,采用两方程方法研究了外国GDP、中国GDP、结构变化、汇率与中国机电产品贸易之间的关系。研究表明：供给因素、结构变化对中国机电产品贸易有重要影响,供给因素对中国机电产品贸易的影响存在不对称性,结构变化对中国机电产品贸易的影响基本对称,汇率对中国机电产品贸易的影响存在不对称性。     

On the incidence–prevalence relation and length‐biased sampling

For many diseases, logistic constraints render large incidence studies difficult to carry out. This becomes a drawback, particularly when a new study is needed each time the incidence rate is investigated in a new population. By carrying out a prevalent cohort study with follow‐up it is possible to estimate the incidence rate if it is constant. The authors derive the maximum likelihood estimator (MLE) of the overall incidence rate, λ, as well as age‐specific incidence rates, by exploiting the epidemiologic relationship, (prevalence odds) = (incidence rate) × (mean duration) (P/[1 ? P] = λ × µ). The authors establish the asymptotic distributions of the MLEs and provide approximate confidence intervals for the parameters. Moreover, the MLE of λ is asymptotically most efficient and is the natural estimator obtained by substituting the marginal maximum likelihood estimators for P and µ into P/[1 ? P] = λ × µ. Following‐up the subjects allows the authors to develop these widely applicable procedures. The authors apply their methods to data collected as part of the Canadian Study of Health and Ageing to estimate the incidence rate of dementia amongst elderly Canadians. The Canadian Journal of Statistics © 2009 Statistical Society of Canada