Energy-Aware Controllability of Complex Networks

Understanding the fundamental principles and limitations of controlling complex networks is of paramount importance across natural, social, and engineering sciences. The classic notion of controllability does not capture the effort needed to control dynamical networks, and quantitative measures of controllability have been proposed to remedy this problem. This article presents an introductory overview of the practical (i.e., energy-related) aspects of controlling networks governed by linear dynamics. First, we introduce a class of energy-aware controllability metrics and discuss their properties. Then, we establish bounds on these metrics, which allow us to understand how the structure of the network impacts the control energy. Finally, we examine the problem of optimally selecting a set of control nodes so as to minimize the control effort, and compare the performance of some simple strategies to approximately solve this problem. Throughout the article, we include examples of structured and random networks to illustrate our results. Expected final online publication date for the Annual Review of Control, Robotics, and Autonomous Systems, Volume 5 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Dynamics of glass windows in mining vehicles under the impacts of rock pieces: numerical and analytical comparison for computational models validation

This study represents the results of linear dynamics analysis of glass plates subjected to rock pieces impacts occurring in underground machines’ windows. The aim of the work is to provide analytical and numerical solutions, obtain frequencies and plate displacement, and compare results of stress calculation for different models. The work performs finite element method (FEM) computations within a modal analysis in 3D statement including a mesh-size convergence analysis. Given approach is a basement for estimation of safety work conditions for operators in cabins of underground mining vehicles when glass windows are subjected to rock bursts and damages.

Do Exchange Rates Fluctuations Influence Gold Price in G7 Countries? New Insights from a Nonparametric Causality-in-Quantiles Test

In the recent era, gold is considered an essential investment source, a source of hedging inflation, and a medium of monetary exchange. The gold and exchange rate nexus become prominent after events like sovereign debt crisis, subprime mortgage crisis, low-interest rate problem, and global financial market solvency. These events attract the attention of researchers and academician for investigating the dynamics of the relationship between gold and exchange rates, and the majority of the studies discusses the linear dynamics, but the non-linear dynamics are ignored. Therefore, the current research investigates the non-linear dynamics of gold price and exchange rate relationship in G7 countries using the new technique named the nonparametric causality approach. This study uses monthly data from the years 1995(January)-2017 (March). The empirical results show that exchange rate return causes gold prices in four out of G7, especially at the low tails. This study also gives valuable insights for monetary policymakers, gold exporter’s international portfolio managers, and hedge fund managers.