Within the framework of this study, the inductive analysis of voltage stability indices’ theoretical formulation, functionality, and overall performances are introduced. The prominence is given to investigate and compare the original indices from three main dimensions (formulation, assessment, and application) standpoints, which have been frequently used and recently attracted. The generalizability of an exhaustive investigation on comparison of voltage stability indices seems problematic due to the multiplicity of the indices, and more importantly, their variety in theoretical foundation and performances. This study purports the first-ever framework for voltage stability indices classification for power system analysis. The test results found that indices in the same category are coherent to their theoretical foundation. The paper highlights the fact that each category of the indices is functional for a particular application irrespective of the drawback ranking, and negated the application of the Jacobian matrix-based indices for online application. Finally, the research efforts put forward a novel classification of voltage stability indices within the main three aspects of formulation, assessment, and behavior analysis in a synergistic manner as an exhaustive reference for students, researchers, scholars, and practitioners related to voltage stability analysis. The simulation tools used were MATLAB^® and PowerWorld^®.

Frequency hopping (FH) has been employed by various wireless systems. For the reception of FH signals, first of all, it is necessary to detect the hopping timing for dehopping. However, it is not easy under low signal-to-noise power ratio (SNR) environment. On the other hand, adaptive array antenna (AAA) technique has been paid much attention. It enables us to improve SNR by beamforming for the direction of arrival (DOA) of the signal. In this paper, we propose a novel AAA that achieves not only beamforming but also the hopping timing detection simultaneously based on the constant modulus algorithm (CMA) criterion. The performance and behaviour of the proposed method are examined through computer simulations.