Tolerance Limits Based on the Multivariate MaxMin Chart

In a previous paper, we have showed how to obtain sequences of number proved random. With this aim, we used sequences of noises y_n such that the conditional probabilities have Lipschitz coefficients not too large. We transformed them using Fibonacci congruences. Then, we obtained sequences x_n which admit the IID model for correct model. This method consisted to value the work of Marsaglia in order to build his CD-ROM. But we did not use Rap Music (as Marsaglia), but texts files. This method also uses an extractor and at the same time the notion of correct models. In this paper, we apply this method to numbers provided by machines or chips. Unfortunately, it is less sure than they have Lipschtiz coefficient not too large. But we can solve this problem: it suffices to use the Central Limit Theorem. We do it modulo 1. In this case, we use a new limit theorem, the XOR Limit theorem : asymptotic distribution of sum of random vectors modulo 1 are asymptotically independent. Then Lipschtiz coefficient of associated sequences are not too large and we can obtain IID sequences by using Fibonacci congruences.     

A New Chart for Monitoring the Covariance Matrix of Bivariate Processes

In this article we consider a control chart based on the sample variances of two quality characteristics. The points plotted on the chart correspond to the maximum value of these two statistics. The main reason to consider the proposed chart instead of the generalized variance | S | chart is its better diagnostic feature, that is, with the new chart it is easier to relate an out-of-control signal to the variables whose parameters have moved away from their in-control values. We study the control chart efficiency considering different shifts in the covariance matrix. In this way, we obtain the average run length (ARL) that measures the effectiveness of a control chart in detecting process shifts. The proposed chart always detects process disturbances faster than the generalized variance | S | chart. The same is observed when the size of the samples is variable, except in a few cases in which the size of the samples switches between small size and very large size.     

董事会约束与企业信用实证研究

本文基于企业信用的角度,设计董事会约束机制评价指标体系,在此基础上建立董事会约束机制评价模型,对董事会约束机制状况进行评价。并将董事会约束状况与企业信用相联系,进行实证分析,观察董事会约束机制对企业信用的影响,借以了解企业在信用保障方面的制度建设状况,使企业信用的制度建设建立在牢固的制度基础之上。     

中国民营上市公司的家族治理与企业价值

本文以最终控制者可以追溯到家族或自然人的民营上市公司为研究对象,将广义家族上市公司区分为真正或狭义家族上市公司(FB)和自然人上市公司(PB)两类,从家族所有、家族控制和家族管理三个维度考察了民营上市公司的家族治理对企业价值的影响。实证结果表明:总体上,家族治理降低了民营上市公司的价值,但家族所有、控制、管理三个维度的影响各不相同,家族治理的绩效最终取决于不同维度之间的组合。鉴于不同类型家族上市公司的主要回归结果皆不相同,本文认为家族企业的不同界定标准会在很大程度上影响到相关实证研究的结论。     

Just-in-time in ATO vehicle manufacturing: The Minivan-Piaggio V.E. case study

The system adopted by Piaggio V.E. to run the production of 'Minivan' aims at conciliating the manufacturing philosophy 'just-in-time' JIT with the creation of a wide range of end-product codes. Some general assumptions for a JIT production, with small lot sizes, are described together with their implementation in the operationorganizing system adopted by Piaggio V.E. for the 'Minivan' assembly line. The strategy pursued by Piaggio V.E. for the Minivan focuses on the quality of the product and the level of service in the form of fast order cycle and a high number of options offered on catalogue. According to the logic of an ATO production system, the customer orders a customized product and the manufacturer does not keep any finished inventory, but aims at effective management of the information flows.     

Employee reactions to behavioural control under conditions of stress: The moderating role of self-efficacy

Extensive research conducted in the occupational stress literature has failed to provide convincing support for the stress-buffering effects of work control on employee adjustment. Drawing on research conducted in the laboratory context, it was proposed that the stress-buffering effects of work control on employee adjustment would be more marked at high, rather than low, levels of self-efficacy. In a sample of 100 customer service representatives, a significant three-way interaction among role conflict, work control and self-efficacy (measured at Time 1) was observed on (low) depersonalization (measured at Time 2). Consistent with expectations, work control reduced the negative effects of work stress on this outcome measure only for employees who perceived high levels of self-efficacy at work. In addition, there was evidence to suggest that self-efficacy moderated the main effects of work control on job satisfaction and somatic health. These findings are discussed in terms of their theoretical contribution to the job strain model, and also in relation to workplace interventions designed to improve levels of employee adjustment.     

The Demands-Control-Support model,locus of control and job dissatisfaction: A longitudinal study

The Job-Demands-Control model (Karasek, 1979) has been widely studied in the job stress field, but the results obtained are frequently contradictory. Therefore, some investigations have expanded the model by including social support and personality characteristics such as locus of control. However, results obtained with these elaborated models have not been conclusive either. The present study sets out to integrate both types of expansions by simultaneously including social support at work and the employee's locus of control in a longitudinal multi-national study among 542 administrative personnel from Belgium, England, Spain, Italy and Israel. Hierarchical moderated multiple regression showed a significant 4-way interaction term (Demands 2 Control 2 Social support 2 Locus of control) on the change in job dissatisfaction. This effect is qualified by the interaction between job demands and control only for an internal locus of control with high social support. Contrary to the prediction of the JDC model, which posits that high control has a buffering effect on job dissatisfaction, the study result indicates a damaging effect of excess control (perceived job control and high internal locus of control), specifically in high social support situations.