论郑和下西洋的航海价值观

探讨对郑和下西洋起决定性作用的航海价值观。通过对历史文献的具体分析,指出郑和下西洋航海价值观的主要内涵是维护封建明王朝的统治,保障统治集团的利益;基本特征是重政治效应,轻经济利益,重官方控制,轻民间开放;历史本质是中国封建社会步入晚期,其上层建筑要顽固地维护和巩固自己的经济基础,从而确保封建专制主义统治的历史产物。认为正是落伍于世界发展潮流的封建主义航海价值观,导致郑和下西洋成为后继无人的千古绝唱,导致具有悠久辉煌古代历史的中国航海事业在近代陷于艰难困苦的中衰泥淖。     

激光宽带熔覆侧向送粉喷嘴设计

激光宽带熔覆侧向送粉喷嘴在激光宽带熔覆中起着重要的作用。文章设计了一种激光宽带熔覆侧向送粉喷嘴, 介绍了喷嘴的结构特性以及工作原理,通过旋转轴杆调节挡条的移动实现粉末出口宽度可调。对喷嘴进行送粉实验,通 过在喷嘴下端放置接粉槽收集粉末,计算粉末的有效利用率,实现粉末利用率在50%左右。     

长江下游地区挖入式港池口门宽度的计算方法

受长江航道的自然地形水深和南京长江大桥通航净空的限制,港口物流服务的腹地纵向延伸和广域化辐射受到较大阻碍,因此,在长江下游河段新建的港口宜尽量兼备承接上游来船转运出海的功能和由海轮转驳江轮的功能。现行规范对于挖入式港池宽度已有较为详细的规定,但对于船舶进出于两码头之间的挖入式港池口门宽度还没有明确的规定和要求,从航道角度出发,引入航行漂角和偏航角概念,着力于阐述船舶进出于两码头之间的挖入式港池口门宽度的计算确定方法。     

Simple Measures of Individual Cluster-Membership Certainty for Hard Partitional Clustering

We propose two probability-like measures of individual cluster-membership certainty that can be applied to a hard partition of the sample such as that obtained from the partitioning around medoids (PAM) algorithm, hierarchical clustering or k-means clustering. One measure extends the individual silhouette widths and the other is obtained directly from the pairwise dissimilarities in the sample. Unlike the classic silhouette, however, the measures behave like probabilities and can be used to investigate an individual’s tendency to belong to a cluster. We also suggest two possible ways to evaluate the hard partition using these measures. We evaluate the performance of both measures in individuals with ambiguous cluster membership, using simulated binary datasets that have been partitioned by the PAM algorithm or continuous datasets that have been partitioned by hierarchical clustering and k-means clustering. For comparison, we also present results from soft-clustering algorithms such as soft analysis clustering (FANNY) and two model-based clustering methods. Our proposed measures perform comparably to the posterior probability estimators from either FANNY or the model-based clustering methods. We also illustrate the proposed measures by applying them to Fisher’s classic dataset on irises.     

Order Statistics from the Generalized Exponential Distribution and Applications

With linear dispersion effects, the standard factorial designs are not optimal estimation of a mean model. A sequential two-stage experimental design procedure has been proposed that first estimates the variance structure, and then uses the variance estimates and the variance optimality criterion to develop a second stage design that efficiency estimates the mean model. This procedure has been compared to an equal replicate design analyzed by ordinary least squares, and found to be a superior procedure in many situations.

However with small first stage sample sizes the variance estiamtes are not reliable, and hence an alternative procedure could be more beneficial. For this reason a Bayesian modification to the two-stage procedure is proposed which will combine the first stage variance estiamtes with some prior variance information that will produce a more efficient procedure. This Bayesian procedure will be compared to the non-Bayesian twostage procedure and to the two one-stage alternative procedures listed above. Finally, a recommendation will be made as to which procedure is preferred in certain situations.     

Interpreting the Principal Component Analysis of Multivariate Density Functions

Functional principal component analysis (FPCA) as a reduction data technique of a finite number T of functions can be used to identify the dominant modes of variation of numeric three-way data.

We carry out the FPCA on multidimensional probability density functions, relate this method to other standard methods and define its centered or standardized versions. Grounded on the relationship between FPCA of densities, FPCA of their corresponding characteristic functions, PCA of the MacLaurin expansions of these characteristic functions and dual STATIS method applied to their variance matrices, we propose a method for interpreting the results of the FPCA of densities. This method is based on the investigations of the relationships between the scores of the FPCA and the moments associated to the densities.

The method is illustrated using known Gaussian densities. In practice, FPCA of densities deals with observations of multidimensional variables on T occasions. These observations can be used to estimate the T associated densities (i) by estimating the parameters of these densities, assuming that they are Gaussian, or (ii) by using the Gaussian kernel method and choosing the matrix bandwidth by the normal reference rule. Thereafter, FPCA estimate is derived from these estimates and the interpretation method is carried out to explore the dominant modes of variation of the types of three-way data encountered in sensory analysis and archaeology.     

The construction of optimal histograms

In this note, a stopping rule is derived that gives the optimal histogram bin width to approximate a probability density function, The procedure minimizes the mean integrated square error between the density function and the histogram, and requires no prior knowledge of the density function.     

A procedure for approximate negative binomial tolerance intervals

In this article, we present a procedure for approximate negative binomial tolerance intervals. We utilize an approach that has been well-studied to approximate tolerance intervals for the binomial and Poisson settings, which is based on the confidence interval for the parameter in the respective distribution. A simulation study is performed to assess the coverage probabilities and expected widths of the tolerance intervals. The simulation study also compares eight different confidence interval approaches for the negative binomial proportions. We recommend using those in practice that perform the best based on our simulation results. The method is also illustrated using two real data examples.     

对青岛海洋文明历史中几个问题的初步探讨

青岛市的建制历史虽然只有百余年,但是却有6000多年海洋文明历史的深厚积淀。在“Q”形青岛滨海文明带上,大汶口文化时期的胶州三里河人,是我国最早闯荡外海的航海者;2200年前从琅琊启航的徐福船队东渡,是史书上记载的年代最早、规模最大的海上远航活动;千帆云集的北宋密州板桥镇,是我国北方唯一设市舶司的东方海上丝绸之路大口岸。在以往打造“帆船之都”过程中,对具有深厚积淀的青岛海洋文明历史鲜有探讨,这不能不说是一种缺憾。在后奥运时代,对悠久的青岛海洋文明史进行一些渐次深入的探讨,以增强“帆船之都”的历史文化底蕴,应有其价值。     

Could hemogram parameters be predictors of dementia in elderly patients?

Objective: To study red cell distribution width (RDW), RDW to platelet ratio (RPR) and mean platelet volume to platelet ratio (MPR), novel inflammatory markers of routine hemogram, of patients with or without dementia, according to the grade of the disease established by Fazekas’s score in magnetic resonance imaging (MRI).

Methods: A total of 1342 cases that undergone cranial MRI study were retrospectively analyzed. Patients without a previous stroke and over 45 years were enrolled in the study. Demographic and laboratory characteristics of the participants were obtained from institutional computerized database. Subcortical and periventricular white matter were evaluated in axial FLAIR images according to Fazekas’s grading scale. Univariate and multivariate analysis were performed for assessing the predictors of Fazekas’s grading scale.

Results: MPR of Fazekas 0, Fazekas 1, Fazekas 2 and Fazekas 3 groups were 3, 3, 4 and 3%, respectively. MPR difference between study groups was not significant (p?=?.32). RPR of Fazekas 0, Fazekas 1, Fazekas 2 and Fazekas 3 groups were 6, 7, 7 and 7%, respectively. RPR difference between study groups was significant (p?Conclusion: We suggest that increased RDW and RPR values may indicate higher Fazekas’s score and dementia in cranial imaging studies. The radiologist should pay particular attention in interpretation of cranial MRI of these patients.