The Use of Wavelet Transform To Evaluate The Sensitivity of Acoustic Emission Attributes To Variation of Cutting Parameters in Milling Aluminium Alloys

Appropriate acquisition and assessment of the dominant acoustic emission (AE) signal attributes generated under various experimental cutting conditions may provide significant knowledge. Consequently, it enhances the efficiency in manufacturing process monitoring and control. However, according to the literature, a lack of information was noticed on the behavior of AE signal attributes under various cutting conditions. Considering that milling is among the most widely used machining operations, the aim of this investigation is to acquire adequate knowledge about interactions between cutting parameters and their direct and indirect effects on the obtained AE signals attributes from the milling process. In the course of this work, the effects of cutting conditions on the attributes calculated from wavelet transform (WT) of AE signals will be presented. WT signal processing was conducted with five models of mother wavelets, and appropriate decomposition numbers were deployed. The approximated signal attributes obtained from each decomposition were assessed. According to signal processing and statistical calculations, cutting speed, feed rate, and coating significantly impacted the variation of AE signal attributes. Also, the most sensitive AE signal attributes and decompositions were rms, std, entropy and energy, and 2nd and 6th decompositions, respectively. The outcome of this work can be integrated into advanced artificial intelligence (AI) approaches to implement real-time monitoring of manufacturing processes.

Decomposable Specht Modules Indexed by Bihooks II

Previously, the last two authors found large families of decomposable Specht modules labelled by bihooks, over the Iwahori–Hecke algebra of type B. In most cases we conjectured that these were the only decomposable Specht modules labelled by bihooks, proving it in some instances. Inspired by a recent semisimplicity result of Bowman, Bessenrodt and the third author, we look back at our decomposable Specht modules and show that they are often either semisimple, or very close to being so. We obtain their exact structure and composition factors in these cases. In the process, we determine the graded decomposition numbers for almost all of the decomposable Specht modules indexed by bihooks.

Description of costandard modules for Schur superalgebra S(2|2) in positive characteristic

In this paper, we shall describe costandard modules [Formula: see text] of restricted highest weight [Formula: see text] for Schur superalgebra [Formula: see text] over an algebraically closed field [Formula: see text] of positive characteristic [Formula: see text]. Additionally, for a restricted highest weight [Formula: see text], we determine all composition factors of the costandard module [Formula: see text]; in particular we compute the decomposition numbers in the process of the modular reduction of a simple module with a restricted highest weight.