Determining Six Sigma success factors in Turkey by using structural equation modeling

Since it includes strong statistical and executive techniques, Six Sigma (SS) succeeded in many countries and different sectors. Especially successful SS applications of many international companies have increased the interest of other companies. As a result of this, the number of implemented SS projects in various countries has increased. Although successful SS projects are often in mind, the number of failed projects because of various reasons is not as low as to be ignored. As well as there are many factors that affect the success level of SS projects, and these factors vary according to countries. In this study, a survey was applied to 117 people who have 1 of SS belts in order to determine success levels of the SS projects in Turkey. By using explanatory factor analysis and structural equation modeling, critical success factors were determined. According to the results, project selection and its scope, quality culture and defining and measuring of metrics were determined as the top factors that are affecting success levels of SS projects applied in Turkey. The results of the study were also compared with the results of similar projects implemented in other countries.     

On the ridge regression estimator with sub-space restriction

In the linear regression model with elliptical errors, a shrinkage ridge estimator is proposed. In this regard, the restricted ridge regression estimator under sub-space restriction is improved by incorporating a general function which satisfies Taylor’s series expansion. Approximate quadratic risk function of the proposed shrinkage ridge estimator is evaluated in the elliptical regression model. A Monte Carlo simulation study and analysis based on a real data example are considered for performance analysis. It is evident from the numerical results that the shrinkage ridge estimator performs better than both unrestricted and restricted estimators in the multivariate t-regression model, for some specific cases.     

环境挑战与对策

雾霾等大气污染、水危机、固体废弃物的资源环境污染问题,以及环境灾害和气候变化问题已经引起全社会的关注。日益凸显的生态环境问题与不可持续的生产和消费方式密切相关;解决环境问题的必由之路是新能源和可再生能源利用、系统角度的能源和资源节约、全生命周期的资源循环利用和创新理念与高新技术的应用。     

Performance analysis of the preliminary test estimator with series of stochastic restrictions

In this paper, the problem of estimation of the regression coefficients in a multiple regression model is considered under the multicollinearity situation when there are series of stochastic linear restrictions available on the regression parameter vector. We have considered the preliminary test ridge regression estimators (PTRREs) based on the Wald, likelihood ratio, and lagrangian multiplier tests. Tables for the maximum and minimum guaranteed efficiency of the PTRREs are obtained, which allow us to determine the optimum choice of the level of significance corresponding to the optimum estimator. Some numerical results support the findings.     

Call Center Delay Announcement Using a Newsvendor‐Like Performance Criterion

The problem of estimating delays experienced by customers with different priorities, and the determination of the appropriate delay announcement to these customers, in a multi‐class call center with time varying parameters, abandonments, and retrials is considered. The system is approximately modeled as an M(t)/M/s(t) queue with priorities, thus ignoring some of the real features like abandonments and retrials. Two delay estimators are proposed and tested in a series of simulation experiments. Making use of actual state‐dependent waiting time data from this call center, the delay announcements from the estimated delay distributions that minimize a newsvendor‐like cost function are considered. The performance of these announcements is also compared to announcing the mean delay. We find that an Erlang distribution‐based estimator performs well for a range of different under‐announcement penalty to over‐announcement penalty ratios.     

民族和谐共生关系的实证研究——基于对广西龙脊地区的调查

本文以广西龙脊地区实地调查的材料为依据,参考相关文献,主要从各民族之间日常生活中的往来和通婚状况等方面,论述境内民族关系解放前后的变化,描述了当代民族之间和谐共生的现状.龙脊的个案说明,在党的民族平等政策指导下,各民族在社会经济共同发展的基础上逐渐走上了融合共生的道路.     

中国皇家脊兽的思想及美学意蕴探析

中国皇家建筑中,脊兽不仅数量巨大,且材质高贵、雕刻精细、种类繁多,达到了屋顶脊兽设计的顶峰。皇家脊兽与中国传统思想文化有着非常密切的联系,在内涵、形式与功能等方面都具有鲜明的美学特征。皇家脊兽对现代建筑设计亦有重要的影响。     

浅谈大学外语教学法中的心理学应用

本文阐述了外语学习的重要性,并总结了多年以来教育家们在外语教育上的重要贡献.同时本文从心理学的角度认真分析了学生在学习过程中所体会到的各种情感变化,进一步说明了外语教学法中应用心理教学的必要性.     

College students’ use of transportation networking companies: An opportunity to decrease substance-impaired driving

Abstract

Objective: To examine the use of transportation networking companies (TNCs) (eg, Uber) among substance-using students in rural and urban college settings. Participants: Students at two large state universities were randomly selected and screened for substance use. Participants reported use of TNCs generally and after substance use and whether TNC use was on or near campus or in other environments. Methods: Data were evaluated using chi-square test, t-tests, and Fisher’s exact tests. Results: Most (85%) participants (n?=?99, 61% response rate) had used a TNC. Among students who used TNCs on/near campus, 98% of rural students used them after substance use compared to 85% of urban students (p?=?.037). We did not detect differences in TNC use by gender or age. Conclusions: Results indicate that TNC use is common after college student substance use and may play a particularly important role in preventing impaired driving for rural campuses where existing transportation options are limited.