Residual Responses to Change Patterns of Autocorrelated Processes

This article studies the residual behaviour of various stationary processes in the presence of change patterns. Three types of change patterns are considered, Additive Outliers, Innovative Outliers and Level Shift. The knowledge of the residual behaviour is important for monitoring production processes. A new method of residual process control is proposed, the patterns chart. In addition to the advantage of detecting change patterns, it distinguishes their nature. The patterns chart's performance is compared to the performance of the special causes control (SCC) chart based on average run length. The results show that the proposed method performs better than a SCC chart. A real case study illustrates that the patterns chart has all the desirable properties of a SCC chart and it overcomes the negative ones.     

Perceptions of undergraduate pharmacy students on plagiarism in three major public universities in Egypt

The survey aimed to capture the perceptions of undergraduate pharmacy students towards plagiarism in three major public universities in Cairo, Egypt: Helwan, Ain-Shams, and Cairo Universities. This was a paper-based self-administrated survey study. The questionnaire was validated by both content and face validation. The final survey form captured the knowledge of the students on plagiarism in terms of definitions, attitudes, and practices. Four hundred and fourteen students, 320 females and 94 males, participated in the study. There was a significant difference between the students who knew the definition of plagiarism among the three universities with p-value = .01. More than half of the participants (67%) claimed that they had no previous education or training on plagiarism. However, after being informed about plagiarism, most of them agreed that plagiarism should be regarded as stealing and a punishment. Additionally, poor study skills and the ease of copying and pasting from the Internet were identified by the majority of the students to be the leading causes of plagiarism. Pharmacy students need to be more educated on plagiarism and its consequences on research and educational ethics. Finally, more strict policies should be incorporated to monitor and control plagiarism in undergraduate sections.     

Si-GARCH: Construction and validation of a new method for the detection of breaking points in models

In this article, we define a new method (Si-GARCH) for signal segmentation based on a class of models coming from econometrics. We make use of these models not to perform prediction but to characterize portions of signals. This enables us to compare these portions in order to determine if there is a change in the signal’s dynamics and to define breaking points with an aim of segmenting it according to its dynamics. We, then, expand these models by defining a new coefficient to improve their accuracy. The Si-GARCH method was tested on several thousands of hours of biomedical signals coming from intensive care units.     

Explicit expressions for gamma spacings and their moments

This work is concerned with the distributions of spacings from a two-parameter gamma distribution, when the shape parameter is a positive integer (or Erlang Distribution). We express the probability density functions of spacings and their moments in closed forms that are easy to implement using computer algebra systems like Mathematica.