Search

Software aging is a problem that was discovered two decades ago. Since then, many research studies have investigated how to manage aging problems caused by memory leakage and accumulated round-off error through resource consumption prediction or state forecasting. When applying state prediction, the performances of various aging classification algorithms are compared by the prediction error. Since forecasting error is not a precise measure and must be estimated, the forecast error variance needs to be analyzed. In this work, we carefully analyze the forecast error variance by three steps. In the first step, we propose a method to decompose the variance by considering the influence of the data sampling process and data partition procedure. In the second step, we use an enhanced Friedman test and the Nemenyi post hoc test to analyze the influence of the data sampling process on the data partitioning procedure. In the last step, a corrected t-test is proposed to compare the performance of two off-the-shelf classification algorithms. The software comparison experiment is based on a real-time web environment. We end this work by proposing a set of feasible suggestions. [ABSTRACT FROM AUTHOR]

The numerical evaluation of high-order modes of a uniform Euler-Bernoulli beam has been studied by reformatting the classical expression of mode shapes. That method, however, is inapplicable to a stepped beam due to the nonuniform expressions of the mode shape for each beam segment. Given that concern, this study develops an alternative method for the numerical evaluation of high-order modes for stepped beams. This method effectively expands the space of high-order modal solutions by introducing local coordinate systems to replace the conventional global coordinate system. This set of local coordinate systems can significantly simplify the frequency determinant of vibration equations of a stepped beam, in turn, largely eliminating numerical round-off errors and conducive to high-order mode evaluation. The efficacy of the proposed scheme is validated using various models of Euler-Bernoulli stepped beams. The principle of the method has the potential for extension to other types of Euler-Bernoulli beams with discontinuities in material and geometry. (The Matlab code for the numerical evaluation of high-order modes for stepped beams can be provided by the corresponding author upon request.) [ABSTRACT FROM AUTHOR]

Abstract: Accurate and reliable analytical measurements are essential when data are to be used to assist the Court in deciding whether or not a drug offence has been committed and therefore about either the innocence or guilt of the accused. The Italian law on drugs demands that compliance with specification limits be assessed on the basis of the actual content of controlled substance contained in seized materials. As a consequence, the role of measurement uncertainty, significant figures and rounding errors becomes critical. In order to assist analysts of forensic toxicology laboratories with illicit drug-related cases, a software tool named Drugs WorkBook (DWB) has been developed. The tool is useful for the quantification of illicit drugs in seized materials along with their measurement uncertainties, the assessment of compliance to specification limits, the printing of comprehensive laboratory reports and the organization of case archives. Other quality control topics, such as control charts, are included. The tool's databases can be edited by the user and maintained up to date. The tool is made freely available to the scientific community. [Copyright &y& Elsevier]

This paper analyzes the rounding errors that occur in the assessment of an interdisciplinary Project-Led Education (PLE) process implemented in the Integrated Master degree on Industrial Management and Engineering (IME) at University of Minho. PLE is an innovative educational methodology which makes use of active learning, promoting higher levels of motivation and students' autonomy. The assessment model is based on multiple evaluation components with different weights. Each component can be evaluated by several teachers involved in different Project Supporting Courses (PSC). This model can be affected by different types of errors, namely: (1) rounding errors, and (2) non-uniform criteria of rounding the grades. A rigorous analysis of the assessment model was made and the rounding errors involved on each project component were characterized and measured. This resulted in a global maximum error of 0.308 on the individual student project grade, in a 0 to 100 scale. This analysis intended to improve not only the reliability of the assessment results, but also teachers' awareness of this problem. Recommendations are also made in order to improve the assessment model and reduce the rounding errors as much as possible. [ABSTRACT FROM AUTHOR]

The implementation of a controller in a Finite Word Length (FWL) context may lead to a deterioration of the global performance, due to parametric errors (quantification of coefficients) and numerical noises (roundoff noises). This deterioration depends on the choise of the realization used to numerically implement the controller. In previous papers, the authors have introduced a new representation allowing to unify different realizations including among others those using q or δ-operators. In this paper, the parametric sensitivity measure is generalized in the MIMO case and used with a specific realization : the Observer-State-Feedback realization. Such a realization is not unique and one problem consists in finding an optimal realization according to that measure. Looking for such a structure is applied on a pratical example : the active control of vehicle longitudinal oscillations. [ABSTRACT FROM AUTHOR]