An asymptotic confidence interval for the process capability index Cpm

Abstract

The use of indices as an estimation tool of process capability is long-established among the statistical quality professionals. Numerous capability indices have been proposed in last few years. C_pm constitutes one of the most widely used capability indices and its estimation has attracted much interest. In this paper, we propose a new method for constructing an approximate confidence interval for the index C_pm. The proposed method is based on the asymptotic distribution of the index C_pm obtained by the Delta Method. Under some regularity conditions, the distribution of an estimator of the process capability index C_pm is asymptotically normal.     

International and National R&D Networks in Unionized Oligopoly

We study the endogenous formation of R&D networks between two domestic and one foreign firms in a unionized oligopoly. We find that the equilibrium networks are sensitive to the extent of knowledge spillovers between networked firms. If spillovers are sufficiently low, the complete network will arise in equilibrium; however, if spillovers are sufficiently high, the foreign partial network that includes a domestic and a foreign firm will arise. Moreover, for intermediate spillovers, no equilibrium network emerges. These results have implications for aggregate outcomes: equilibrium networks are not necessarily optimal in terms of aggregate effective R&D and aggregate firm profits.     

Error analysis of stochastic flight trajectory prediction models

This paper focuses on the analysis of errors between a flight trajectory prediction model and flight data. A novel stochastic prediction flight model is compared with the popular fly-by and fly-over turn models. The propagated error is measured using either spatial coordinates or angles. Depending on the case, the distribution of error is estimated and confidence bounds for the linear and directional mean are provided for all three stochastic flight models.     

Automatic sleep stage classification based on easy to register signals as a validation tool for ergonomic steering in smart bedding systems

Ergonomic sleep studies benefit from long-term monitoring in the home environment to cope with daily variations and habituation effects. Polysomnography allows to asses sleep accurately, but is costly, time-consuming and possibly disturbing for the sleeper. Actigraphy is cheap and user friendly, but for many studies lacks accuracy and detailed information. This proof-of-concept study investigates Least-Squares Support Vector Machines as a tool for automatic sleep stage classification (Wake-N1-Rem to N2-N3 separation), using automatic trainingset-specific filtered features as derived from three easy to register signals, namely heart rate, breathing rate and movement. The algorithms are trained and validated using 20 nights out of a 600 night database from over 100 different healthy persons. Different training and test set strategies were analyzed leading to different results. The more person-specific the training nights to the test nights, the better the classification accuracy as validated against the hypnograms scored by experts from the full polysomnograms. In the limit of complete person-specific training, the accuracy of the algorithm on the test set reached 94%. This means that this algorithm could serve its use in long-term monitoring sleep studies in the home environment, especially when prior person-specific polysomnographic training is performed.     

A Polynomial Logistic Distribution and its Applications in Finance

The importance of Logistic distribution has been widely recognized in many applied areas such as, demography, population studies, finance, agriculture, etc. Since its introduction as a model, much attention has been paid to the study of several generalizations of it, which would offer additional flexibility when data fitting is chased. In the present paper we introduce and develop a natural generalization of the Logistic distribution by considering a probability model whose logit cumulative distribution function transformation is of polynomial type. The performance of the model's fitting to financial data, using different parameter estimation methods, is also investigated.     

RETIREMENT,PERSONALITY, AND WELL‐BEING

This study investigates how two sources of individual heterogeneity—personality and gender—impact the well‐being effects of retirement. Using data on older men and women from the British Household Panel Survey and its continuation, Understanding Society, we estimate the causal effect of retirement on satisfaction with overall life and domains of life in the presence of personality characteristics. As retirement is often considered to be a choice and thus may be endogenous to individual‐level characteristics, we use the eligibility ages for basic state pension in the United Kingdom as instruments for retirement. We find that retirement increases leisure satisfaction of both males and females but not necessarily life satisfaction and income satisfaction. We further show that certain personality characteristics affect the well‐being of female retirees. For males, however, personality does not seem to matter in how they cope with retirement. (JEL I31, J26, A12, C23)     

Monitoring of zero-inflated binomial processes with a DEWMA control chart

Control charts are widely used for monitoring quality characteristics of high-yield processes. In such processes where a large number of zero observations exists in count data, the zero-inflated binomial (ZIB) models are more appropriate than the ordinary binomial models. In ZIB models, random shocks occur with probability θ, and upon the occurrence of random shocks, the number of non-conforming items in a sample of size n follows the binomial distribution with proportion p. In the present article, we study in more detail the exponentially weighted moving average control chart based on ZIB distribution (ZIB-EWMA) and we also propose a new control chart based on the double exponentially weighted moving average statistic for monitoring ZIB data (ZIB-DEWMA). The two control charts are studied in detecting upward shifts in θ or p individually, as well as in both parameters simultaneously. Through a simulation study, we compare the performance of the proposed chart with the ZIB-Shewhart, ZIB-EWMA and ZIB-CUSUM charts. Finally, an illustrative example is also presented to display the practical application of the ZIB charts.     

Decisive FDI obstacles as an explanatory reason for limited FDI inflows in an EMU member state: The case of Greece

A questionnaire survey covering MNCs that had invested in Greece during the period 1995–2003 is carried out in order to determine the barriers of inward FDI in Greece through a phase of increased expectations on foreign investment from hosting the 2004 Olympiad. The underlying assumption made is that the views of the local managers reflect the views of the mother company when deciding to invest. Although the findings represent the time that the investment took place, the influence of the conditions shaping the economic environment at the time the survey was carried out is also discussed. The findings indicate that the primary barriers to foreign investors are bureaucracy, taxation, corruption, and the labor market structure and support those of previous quantitative studies, leading to the conclusion that there is no progress made regarding these factors, in order to enhance FDI attractiveness. It becomes crucial for Greece to modernize and upgrade state mechanisms, through a more effective organization and administrative policies.     

A generalized polynomial-logistic distribution and applications

ABSTRACT

In the present article we introduce a new class of distributions which nests the classical Logistic distribution and offers additional flexibility when data fitting is chased. We provide exact expressions for its moments and absolute moments, investigate its ageing properties, and discuss several techniques for estimating its parameters. Finally, we use the new family to build a parametric model that describes accurately the Euro/CAD exchange reference rates for the period 1/4/1999–12/31/2011.