分配格上对角占优阵的幂收敛性与可实现问题

本文得到分配格上行（或列）对角占优阵Ａ的不变式ｐｅｒ（Ａ）的特征,以及Ａ的幂序列的收敛性。给出对称方阵可实现的充要条件,对于有界分配格上的行（或列）对角占优阵给出其可逆的充要条件。     

一种对称损失下Pareto分布参数的Bayes估计

本文讨论了给定容量n的一个Pareto样本在对称损失函数下,Pareto分布参数的Bayes估计,证明了这一估计是可容许的,并给出了Bayes的置信下限。     

论"意与境浑"不等于情景交融

情景交融一般是指创作主体的情感渗透于客体景物而形成的一种情寓景中的艺术形态."意与境浑"则是指诗所描写的自然环境和社会环境,不但能令处身于环境的主体感发、引起某种思想感情,而且能令读者感到这环境与情意之间的因果关系全然可信、自然天成而和谐统一.     

刑事辩护中律师与委托人的关系

在刑事辩护中,当辩护律师与委托人的意见发生分歧时,一般以为律师不应违背委托人的意愿做出有损其合法利益的辩护。然而,当律师认为委托人的主观意愿违背了其本身的客观利益时,律师应当如何选择这一问题在法学界一直没有定论。文章首先指出:现实生活中对律师和委托人关系存在两种不同理解:完全委托模式和诉讼代行模式。在列举了美国法曹协会和日本律师联合会对上述问题的看法和有关规定后,针对日美两国对刑事辩护人职能和地位的认识差异开展了比较分析。最后,作者提出刑事辩护和律师应当开展有利于委托人的辩护活动,尊重委托人的选择和主观意愿,并通过主动的接触和沟通与委托人建立充分的信赖关系。在辩护律师与委托人在辩护方针和策略上出现矛盾时,辩护律师应当加强对委托人的理解,不能将自己的意志强加于委托人。当然,在一些特定的情况下(如委托人的精神残疾、死刑案件等),允许辩护律师凭借自身的判断为委托人提供妥当的辩护服务。      

Double unit root tests for cross-sectionally dependent panel data

This paper proposes various double unit root tests for cross-sectionally dependent panel data. The cross-sectional correlation is handled by the projection method [P.C.B. Phillips and D. Sul, Dynamic panel estimation and homogeneity testing under cross section dependence, Econom. J. 6 (2003), pp. 217–259; H.R. Moon and B. Perron, Testing for a unit root in panels with dynamic factors, J. Econom. 122 (2004), pp. 81–126] or the subtraction method [J. Bai and S. Ng, A PANIC attack on unit roots and cointegration, Econometrica 72 (2004), pp. 1127–1177]. Pooling or averaging is applied to combine results from different panel units. Also, to estimate autoregressive parameters the ordinary least squares estimation [D.P. Hasza and W.A. Fuller, Estimation for autoregressive processes with unit roots, Ann. Stat. 7 (1979), pp. 1106–1120] or the symmetric estimation [D.L. Sen and D.A. Dickey, Symmetric test for second differencing in univariate time series, J. Bus. Econ. Stat. 5 (1987), pp. 463–473] are used, and to adjust mean functions the ordinary mean adjustment or the recursive mean adjustment are used. Combinations of different methods in defactoring to eliminate the cross-sectional dependency, integrating results from panel units, estimating the parameters, and adjusting mean functions yields various available tests for double unit roots in panel data. Simple asymptotic distributions of the proposed test statistics are derived, which can be used to find critical values of the test statistics.

We perform a Monte Carlo experiment to compare the performance of these tests and to suggest optimal tests for a given panel data. Application of the proposed tests to a real data, the yearly export panel data sets of several Latin–American countries for the past 50 years, illustrates the usefulness of the proposed tests for panel data, in that they reveal stronger evidence of double unit roots than the componentwise double unit root tests of Hasza and Fuller [Estimation for autoregressive processes with unit roots, Ann. Stat. 7 (1979), pp. 1106–1120] or Sen and Dickey [Symmetric test for second differencing in univariate time series, J. Bus. Econ. Stat. 5 (1987), pp. 463–473].     

Markov switching model of nonlinear autoregressive with skew-symmetric innovations

We consider data generating structures which can be represented as a Markov switching of nonlinear autoregressive model with considering skew-symmetric innovations such that switching between the states is controlled by a hidden Markov chain. We propose semi-parametric estimators for the nonlinear functions of the proposed model based on a maximum likelihood (ML) approach and study sufficient conditions for geometric ergodicity of the process. Also, an Expectation-Maximization type optimization for obtaining the ML estimators are presented. A simulation study and a real world application are also performed to illustrate and evaluate the proposed methodology.     

Comparison of experiments for a class of positively dependent random variables

Using Blackwell's definition for comparison of experiments, it is shown that some sets of positively dependent random variables are less informative than similar sets of independent random variables. It is also shown that the information content of symmetric multivariate normal random vectors with a common known variance increases as the common correlation coefficient decreases. Some results which compare members of two-parameter exponential families are also included.     

共轭对称数据DFT,FFT的研究及应用

本文研究了共轭对称输入序列的离散付里叶变换DFT的特点,推导出高效的共轭对称数据FFT算法,并将其应用于机构学中对称连杆曲线的综合,取得了令人满意的结果.     

量子Hall效应与Berry相因子

将绝热过程中的Berry相因于的概念推广到简并系统.在对称规范条件下研究了量子Hall效应与Berry相因子之间的关系,导出了量子Hall电导率与Berry相因子之间的关系,理论分析与Klitzing,Tsui等人的实验结果一致.