Quelling Cabin Noise in Turboprop Aircraft via Active Control

Cabin noise in turboprop aircraft causes passenger discomfort, airframe fatigue, and employee scheduling constraints due to OSHA standards for exposure to high levels of noise. The noise levels in the cabins of turboprop aircraft are typically 10 to 30 decibels louder than commercial jet noise levels. However, unlike jet noise the turboprop noise spectrum is dominated by a few low frequency tones. Active structural acoustic control is a method in which the control inputs (used to reduce interior noise) are applied directly to a vibrating structural acoustic system. The control concept modeled in this work is the application of in-plane force inputs to piezoceramic patches bonded to the wall of a vibrating cylinder. The goal is to determine the force inputs and locations for the piezoceramic actuators so that (1) the interior noise is effectively damped; (2) the level of vibration of the cylinder shell is not increased; and (3) the power requirements needed to drive the actuators are not excessive. Computational experiments for data taken from a computer generated model and from a laboratory test article at NASA Langley Research Center are provided.     

Nonparametric repeated significance tests for one-way anova with adoptation to multiple comparisons

Based on two-sample rank order statistics, a repeated significance testing procedure for a multi-sample location problem is considered. The asymptotic distribution theory of the proposed tests is given under the null hypothesis as well as under local alternatives. A Bahadur efficiency result of the repeated significance test relative to the terminal test based solely on the target sample size is presented. In the adaptation of the proposed tests to multiple comparisons, an asymptotically equivalent test statistic in terms of the rank estimators of the location parameters is derived from which the Scheffé method of multiple comparisons can be obtained in a convinient way.     

高校学生党支部建在班级的实践与探索

高校学生党支部是党在学生中的最基层党组织,如何设置和建设是学生党建工作重要的基础环节。实践证明,把学生党支部建在班上,能切实地加强学生党支部的建设,更好地推动高校学生党建工作的开展。     

On the improved estimation of a function of the scale parameter of an exponential distribution based on doubly censored sample

In the present article, we have studied the estimation of entropy, that is, a function of scale parameter ln⁡σ of an exponential distribution based on doubly censored sample when the location parameter is restricted to positive real line. The estimation problem is studied under a general class of bowl-shaped non monotone location invariant loss functions. It is established that the best affine equivariant estimator (BAEE) is inadmissible by deriving an improved estimator. This estimator is non-smooth. Further, we have obtained a smooth improved estimator. A class of estimators is considered and sufficient conditions are derived under which these estimators improve upon the BAEE. In particular, using these results we have obtained the improved estimators for the squared error and the linex loss functions. Finally, we have compared the risk performance of the proposed estimators numerically. One data analysis has been performed for illustrative purposes.     

中国区域间物流产业专业化分工实证研究

利用中国物流业1999-2004年的数据,本文首先描述了物流业在中国的区域分布及其变化。其次,本文在现有文献的基础上构建了衡量区域物流行业专门化和区域间物流业同构程度的较为合理的指标和方法组合,并利用这些指标对上述问题进行了详细分析。分析结果表明,近年来中国区域物流专门化分工及各区域内省市物流行业同构总体呈上升趋势,而各区域间的差别大致上可以用自然禀赋理论和外部效应理论给出合理的解释。得出大区域物流行业专门化程度是由各子区域本身的主导行业专门化程度和各子区域间经济同构程度共同影响的结论。     

《穆天子传》中的瑶池今地考

本文列举了古今各家对《穆天子传》中瑶池今地的种种看法并认为 :可用唐朝设置瑶池都督府于莫贺城证实 ,瑶池今地应为今天山天池     

Well-Being Outcomes in Bolivia: Accounting for the Effects of Ethnicity and Regional Location

This study assesses well-being differences in Bolivia. We specifically investigate whether ethnicity and regional location explain differences in housing quality, material wealth, sanitation, and educational achievement in Bolivia. We use the 1994 and 1998 DHS surveys of 9114 and 12109 cases, respectively, to test the study hypotheses, which predict that indigenous ethnicity and highland location negatively affect well-being. Results show that in both surveys, indigenous households had lower levels of housing quality, material wealth, and sanitation as compared to non-indigenous households. Indigenous heads of household also showed lower levels of education as compared to non-indigenous heads of household. Households located in the highlands showed lower levels of housing quality and sanitation in both 1994 and 1998. Highland location was a significant predictor of material wealth in the 1998 model but not in the 1994 one. Highland location was not a significant predictor of education in either the 1994 or 1998 models. Rural–urban location had the largest influence on well-being.     

An optimal sign test for one-sample bivariate location model using an alternative bivariate ranked-set sample

The aim of this paper is to find an optimal alternative bivariate ranked-set sample for one-sample location model bivariate sign test. Our numerical and theoretical results indicated that the optimal designs for the bivariate sign test are the alternative designs with quantifying order statistics with labels {((r+1)/2, (r+1)/2)}, when the set size r is odd and {(r/2+1, r/2), (r/2, r/2+1)} when the set size r is even. The asymptotic distribution and Pitman efficiencies of these designs are derived. A simulation study is conducted to investigate the power of the proposed optimal designs. Illustration using real data with the Bootstrap algorithm for P-value estimation is used.     

位置参数的同时估计

在平方损失下，考虑ｐ（ｐ≥３）个位置参数的同时估计．对均匀分布、双指数分布给出了控制通常估计量的改进估计量，推广了Ｓｈｉｎｏｚａｋｉ（１９８４）的主要结果．     

刍议高师声乐教学中的混声训练

高师声乐教学进行混声训练的学习 ,可以在短时间内 ,更有效地帮助学生扩展音域、统一声区、美化音色 ,是正确的、科学的发声方法