Application of ridge regression and factor analysis in design and production of alloy wheels

This study proposes using statistical approaches to help with both the design and manufacture of wheels. The quality of a wheel is represented by the mechanical properties of spokes. Variation in the mechanical properties of different wheels is attributed to two sources, i.e. between-model variation and within-model variation. The between-model variation is due to different shapes of different wheel models. To model the effect of shapes on the mechanical properties, we first specify eight shape variables potentially critical to the mechanical properties, and then we collect relevant data on 18-wheel models and perform ridge regression to find the effects of these variables on the mechanical properties. These results are linked to the solidification theory of the A356 alloy. The within-model variation is due to natural variability and process abnormality. We extract mechanical data of a particular wheel model from the database. Factor analysis is employed to analyze the data with a view to identifying the latent factors behind the mechanical properties. We then look into the microstructure of the alloy to corroborate the fact that these two latent factors are essentially the Si phase and the Mg₂Si phase, respectively. These results can be used to efficiently identify the root cause when the manufacturing process goes wrong.     

Modified and Restricted r-k Class Estimators

In this article, we introduce the modified r-k class estimator and the restricted r-k class estimator. We compare the performances of the new estimators to the r-k class estimator with respect to the matrix mean square error (MSE) criterion. As a special case of the restricted r-k class estimator, we obtain the restricted principal components regression (RPCR) estimator. Finally, we conduct a Monte Carlo simulation study and a numerical example to investigate the performances of the proposed estimators by the scalar mean square error (mse) criterion.     

山东省粮食产量连续十年增长的保障因素分析

1978年至2012年山东省粮食产量数据显示出明显的"三阶段"波动特征。借助主成分分析与岭回归的方法,对不同阶段影响山东省粮食产量的主要因素进行实证检验,结果显示,近阶段山东省粮食产量连续10年增长的主导因素是农业生产条件的持续改善,主要包括农机总动力、有效灌溉面积、化肥使用折纯量、农村用电量及支农支出的有效保障。但同时也存在化肥使用量增速过快、复种指数偏低等制约因素,会在一定程度上降低粮食持续增产的可能性。加强水利建设、保证复种指数、提高补贴力度等可以作为进一步保证粮食安全、促进粮食增产的措施。     

湖南省住宅价格变动因素的实证研究——以长沙市为例

分析长沙市住宅价格变动因素,可以发现,影响长沙市房地产市场价格变动的因素主要有：土地价格,城乡居民收入,经济的增长,物价水平.各级地方政府应从发挥政府政策主导影响、发挥市场调节机制作用、完善基础设施建设和加强产业发展引导等方面制定相配套的经济社会发展政策.     

经世致用与老子思想的融合--魏源《老子本义》思想剖析

魏源从今文经学经世致用的原则出发,对老子的思想进行了新诠解,并视<老子>为"救世之书".他又结合自己的时代特点,对老子的社会政治价值进行了深入挖掘,对"自然无为"、"无欲为体,无为为用"、"慈、俭、不敢为天下先"、"小国寡民"等思想作出了新的诠解,体现出强烈的忧患意识与救世情怀,实现了对老子思想的超越,也开启了近代道家思想研究的新阶段.     

Jack’d,a Mobile Social Networking Application: A Site of Exclusion Within a Site of Inclusion

User-generated smartphone applications have created a new level of virtual connectivity for gay males, one in which users can create profiles and meet other users as nearby or as far away as possible. For those within close proximity, the other users can be considered their “virtual neighbors.” Although the applications are theoretically designed to be places of inclusion and not exclusion, where any gay male with economic means can download an application, many profiles have been created that exclude other users. Through an examination of profiles on one such application, Jack’d, exclusion is found in the way users celebrate and reinforce ideas of traditional masculinity and denigrate and reinforce stereotypic ideas of femininity embodied by some gay men. Jack’d, and other user-generated smartphone applications, can be read as virtual neighborhoods where one is excluded based on their gender performance.     

“Hedge Your Bets”: Technology’s Role in Young Gay Men’s Relationship Challenges

Technology is playing an increasingly pervasive role among young gay men in the process of meeting potential romantic or sexual partners. We investigated challenges posed by technology related to young gay men’s relationships. Focus groups (n = 9) of young gay men aged 18–24 (n = 43) were transcribed verbatim, and thematic analysis was used to identify two major themes regarding challenges to relationship development and maintenance. Subthemes include unrealistic expectations of relationships, inauthentic self-presentation online, sexual primacy over romance, increased opportunities for infidelity, and jealousy. The implications of this study for sexual education and sexual health promotion are discussed.     

Improved robust ridge M-estimation

It is developed that non-sample prior information about regression vector-parameter, usually in the form of constraints, improves the risk performance of the ordinary least squares estimator (OLSE) when it is shrunken. However, in practice, it may happen that both multicollinearity and outliers exist simultaneously in the data. In such a situation, the use of robust ridge estimator is suggested to overcome the undesirable effects of the OLSE. In this article, some prior information in the form of constraints is employed to improve the performance of this estimator in the multiple regression model. In this regard, shrinkage ridge robust estimators are defined. Advantages of the proposed estimators over the usual robust ridge estimator are also investigated using Monte-Carlo simulation as well as a real data example.     

Ridge estimation in generalized linear models and proportional hazards regressions

Conventionally, a ridge parameter is estimated as a function of regression parameters based on ordinary least squares. In this article, we proposed an iterative procedure instead of the one-step or conventional ridge method. Additionally, we construct an indicator that measures the potential degree of improvement in mean squared error when ridge estimates are employed. Simulations show that our methods are appropriate for a wide class of non linear models including generalized linear models and proportional hazards (PHs) regressions. The method is applied to a PH regression with highly collinear covariates in a cancer recurrence study.     

习近平贫困治理重要论述的理论意蕴及在四川藏区的实践应用

习近平关于贫困治理的系列重要论述承载着丰富的理论意蕴：其一,改革创新是贫困治理的长效保障;其二,人民群众是贫困治理的基石和源泉;其三,精准扶贫是全面建成小康社会的必要路径。本文立足于习近平贫困治理重要论述的理论意蕴,构建了精准扶贫与精细化治理有效对接的理论分析框架,对四川藏区贫困治理的现状及问题进行了深入分析,指出在后精准脱贫阶段,进一步增强四川藏区扶贫实效,需要创新集聚启动机制、完善瞄准定位机制、构建利益联结机制、健全监测调控机制、探索益贫发展机制、构建应急机制。