Approximation of the Bivariate Renewal Function

Recently, Kambo and his co-researchers (2012) proposed a method of approximation for evaluating the one-dimensional renewal function based on the first three moments. Their method is simple and elegant, which gives exact values for well-known distributions. In this article, we propose an analogous method for the evaluation of bivariate renewal function based on the first two moments of the variables and their joint moment. The proposed method yields exact results for certain widely used bivariate distributions like bivariate exponential distribution, bivariate Weibull distributions, and bivariate Pareto distributions. An illustrative example in the form of a two-dimensional warranty problem is considered and comparisons of our method are made with the results of other models.     

GPS接收机P(Y)直捕方法研究

GPS接收机P(Y)直捕算法是基于存储的滑动相关搜索,并利用FFT将时频二维联合搜索变成时域一维搜索。同时,考虑位同步点已知的条件,接收资源池只需存储一段接收序列,缩短了捕获时间且利于硬件实现。仿真结果表明,多普勒频移为±5kHz时,所带来的峰值衰减为2dB左右,本地信号与接收信号对齐时出现明显的相关峰,很好地实现了捕获功能;提出了用重叠分段补零FFT操作实现并行相关,成倍降低了捕获时间;提出了利用位同步信息,避免了码极性翻转可能引起的信噪比损耗;针对码相位漂移,提出了优化捕获策略,可在短时间内完成重捕。     

BAYESIAN SUBSET SELECTION AND MODEL AVERAGING USING A CENTRED AND DISPERSED PRIOR FOR THE ERROR VARIANCE

This article proposes a new data‐based prior distribution for the error variance in a Gaussian linear regression model, when the model is used for Bayesian variable selection and model averaging. For a given subset of variables in the model, this prior has a mode that is an unbiased estimator of the error variance but is suitably dispersed to make it uninformative relative to the marginal likelihood. The advantage of this empirical Bayes prior for the error variance is that it is centred and dispersed sensibly and avoids the arbitrary specification of hyperparameters. The performance of the new prior is compared to that of a prior proposed previously in the literature using several simulated examples and two loss functions. For each example our paper also reports results for the model that orthogonalizes the predictor variables before performing subset selection. A real example is also investigated. The empirical results suggest that for both the simulated and real data, the performance of the estimators based on the prior proposed in our article compares favourably with that of a prior used previously in the literature.     

洋桔梗叶盘高频率不定芽诱导的初步研究

采用正交设计法研究了细胞分裂素ZT,生长素NAA,培养基pH值和光照强度对洋桔梗叶盘不定芽诱导的影响.结果表明,实验的4个因子对洋桔梗叶盘不定芽都具有极显著的诱导作用,最佳培养基和培养条件为:MS ZT 0.5 mg/L NAA 0.01 mg/L,培养基pH值为6.3,光照强度为3000 lx.该处理中每叶盘再生不定芽数平均达9.41个.     

"不美"论纲--关于一个新的美学基本范畴的思考

文章围绕“不美”这一新的审美范畴命题,探讨了“不美”发生的事实依据、时代根源、本质特征以及在审美心理和文艺实践中的具体表现形态,从基础理论方面触及了当代审美潮流的新特征和新趋向。     

基于分数本征特征的手写数字识别

特征提取是手写体数字识别研究中的重要问题,有效、稳定的特征是提高识别率和识别精度的关键。该文提出了一种基于分数本征特征和核非线性分类器的手写数字识别方法,首先找到时频平面的一个轴进行分数傅里叶变换,使不同类别样本在这个轴上最大限度地分开,然后用主元分析进行降维,得到比较稳健的低维特征,再将常用分类器用于特征分类,实现对手写数字的识别。对实际数据进行实验,结果表明上述本征特征与核非线性分类器相结合有较高的识别率和训练、分类效率。     

BATHTUB-TYPE CURVES IN RELIABILITY AND BEYOND

Finding optimal, or at least good, maintenance and repair policies is crucial in reliability engineering. Likewise, describing life phases of human mortality is important when determining social policy or insurance premiums. In these tasks, one searches for distributions to fit data and then makes inferences about the population(s). In the present paper, we focus on bathtub‐type distributions and provide a view of certain problems, methods and solutions, and a few challenges, that can be encountered in reliability engineering, survival analysis, demography and actuarial science.     

对中国传统行政文化宗法化倾向的探讨

在中国社会由传统向现代的转型过程中,行政文化也进入了激变再生的重要时期。考察我国传统行政文化的形成和发展,可以清楚地看到,在其历经原始社会后期、奴隶社会和封建社会的历史传承中,一个非常鲜明的基本特征就是宗法化倾向,这一倾向表现在行政文化功能的实现过程中就是它的浓郁的人情化色彩。因此,要进行我国的行政体制改革,就必须思考对传统的行政文化进行改造并保持行政文化效能健全与连续的问题,这也是我国行政体制改革成败的一个关键。     

Approximation of density functions by orthogonal series with grouped data

Summary Letg(x) andf(x) be continuous density function on (a, b) and let {ϕ_j} be a complete orthonormal sequence of functions onL ₂(g), which is the set of squared integrable functions weighted byg on (a, b). Suppose that over (a, b). Given a grouped sample of sizen fromf(x), the paper investigates the asymptotic properties of the restricted maximum likelihood estimator of density, obtained by setting all but the firstm of the ϑ_j’s equal to0. Practical suggestions are given for performing estimation via the use of Fourier and Legendre polynomial series. Research partially supported by: CNR grant, n. 93. 00837. CT10.     

高校会计制度改革初探

根据《中华人民共和国会计法》等法规条例,参照国际会计准则,高等学校的会计改革应当按基金会计原则,采用＂资产＝负债＋基金结余＂的会计平衡公式,实行预算会计模式的转换．