An Examination of the Robustness to Non Normality of the EWMA Control Charts for the Dispersion

The EWMA control chart is used to detect small shifts in a process. It has been shown that, for certain values of the smoothing parameter, the EWMA chart for the mean is robust to non normality. In this article, we examine the case of non normality in the EWMA charts for the dispersion. It is shown that we can have an EWMA chart for dispersion robust to non normality when non normality is not extreme.Average run length, Control charts, Exponntially weighted moving average control chart, Median run length, Non normality, Statistical process control

EWMA Chart and Measurement Error

Measurement error is a usually met distortion factor in real-world applications that influences the outcome of a process. In this paper, we examine the effect of measurement error on the ability of the EWMA control chart to detect out-of-control situations. The model used is the one involving linear covariates. We investigate the ability of the EWMA chart in the case of a shift in mean. The effect of taking multiple measurements on each sampled unit and the case of linearly increasing variance are also examined. We prove that, in the case of measurement error, the performance of the chart regarding the mean is significantly affected.Exponentially weighted moving average control chart, Average run length, Average time to signal, Measurement error, Markov chain, Statistical process control

Control Charts for the Lognormal Distribution

Control Charts are the main tools of Statistical Process Control. They are used for deciding whether a process is statistically stable or not. Much theory and many applications have been developed for the Gaussian (Normal) distribution in this area. However, in real data sets we usually face up nonnormal processes. Consequently, this theory does not apply. In the present paper, we focus attention on the lognormal distribution that can be considered as a special nonnormal case. In particular, we present the Shewhart Control Charts developed up to now, under such distributional assumptions and a new Control Chart based on the CUSUM theory.Control chart, Nonnormality, Shewhart, CUSUM, Average run length, Lognormal

The Use of Indices in Surveys

The paper deals with some new indices for ordinal data that arise from sample surveys. Their aim is to measure the degree of concentration to the “positive” or “negative” answers in a given question. The properties of these indices are examined. Moreover, methods for constructing confidence limits for the indices are discussed and their performance is evaluated through an extensive simulation study. Finally, the values of the indices defined and their confidence intervals are calculated for an example with real dataMultinomial proportions, Ordinal data, Indices, Confidence intervals, Sample surveys

Developing intrinsically motivated information systems - a critical systems approach

This paper deals with the problematic of development methodologies for organisational information systems and especially with their application to business systems. Historically, information systems development methodologies tend to fail, because either they take the organisational purposefulness for granted, or they do not analyse it thoroughly. This paper's position is that the analysis, and the definition or redefinition of the systemic purpose are regarded as the utmost expression of the system 's purposefulness. This is to be achieved by ensuring the participation of all the stakeholders who affect, or are affected by, a particular business system's operations. The nature of participation, defined as a process of the stakeholders' perceptual exchanges, is deemed to be problematic in itself, due to the influence exerted upon it by organisational power, coercion and false consciousness. The paper highlights the philosophical reasons for the failures of information systems development methodologies, and provides a conceptual solution to this problematic as well as a strategy for the development of intrinsically motivated organisational information systems. The intrinsically motivated information systems methodology outlined here (BSPA) is intended to yield organisational information systems that demonstrably improve co-ordination of organisational activities, by enabling the development and maintenance of a single/multifaceted view of purpose throughout organisations

On Certain Indices for Ordinal Data with Unequally Weighted Classes

In this paper, some new indices for ordinal data are introduced. These indices have been developed so as to measure the degree of concentration on the “small” or the “large” values of a variable whose level of measurement is ordinal. Their advantage in relation to other approaches is that they ascribe unequal weights to each class of values. Although, they constitute a useful tool in various fields of applications, the focus here is on their use in sample surveys and specifically in situations where one is interested in taking into account the “distance” of the responses from the “neutral” category in a given question. The properties of these indices are examined and methods for constructing confidence intervals for their actual values are discussed. The performance of these methods is evaluated through an extensive simulation study.

Enhancing the Collection Process for the Delphi Technique

The purpose of this manuscript is to describe a process that enhances the data collection process for a Delphi technique. The approach consists of online platforms to expedite the process and reinforce the validity of the Delphi technique. The context of the study was the identification of quality indicators for visual-based learning material development for Technology Education programs for grades 7-12

Effect of Estimation on the Univariate Control Charts for Process Dispersion

Control charts are extensively used in many real world applications. Since process parameters are rarely known common practice is to estimate them. Then, the control limits are modified and become actually random variables. In this paper, we deal with the univariate control charts for dispersion for both rational subgroups and individual measurements. We study the effect of estimating the process parameters of this chart on the first two moments of the run length distribution. The results are used for proposing appropriate values of sample size and number of samples in order to make the estimated control limits perform as the theoretical ones.Shewhart charts, ARL, S chart, X chart

The Complexity of the Caspian Basin

The collapse of the Soviet Union and the emergence of newly independent States marked the uprising of a new era in the region of the Caspian Basin. Failing to reach a consensus regarding the legal nature of the Caspian, Russia, Turkmenistan, Iran, Azerbaijan, and Kazakhstan’s policies have been characterized by a perpetual pursuit of establishing themselves as key-role agents in the region. The question about “Lake or Sea” is yet to be answered after many decades. This paper focuses on analyzing the significance of the Caspian Basin for the littoral States and how it determines their political agenda

Shape memory alloy honeycombs: experiments & simulation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76238/1/AIAA-2007-1739-156.pd