Digital Twins for Moving Target Defense Validation in AC Microgrids

Cyber-physical microgrids are vulnerable to stealth attacks that can degrade their stability and operability by performing low-magnitude manipulations in a coordinated manner. This paper formulates the interactions between CSAs and microgrid defenders as a non-cooperative, zero-sum game. Additionally, it presents a hybrid Moving Target Defense (MTD) strategy for distributed microgrids that can dynamically alter local control gains to achieve resiliency against Coordinated Stealth Attacks (CSAs). The proposed strategy reduces the success probability of attack(s) by making system dynamics less predictable. The framework also identifies and removes malicious injections by modifying secondary control weights assigned to them. The manipulated signals are reconstructed using an Artificial Neural Network (ANN)-based Digital Twin (DT) to preserve stability. To guarantee additional immunity against instability arising from gain alterations, MTD decisions are also validated (via utility and best response computations) using the DT before actual implementation. The DT is also used to find the minimum perturbation that defenders must achieve to invalidate an attacker's knowledge effectively.Comment: IEEE Energy Conversion Congress and Expo (ECCE) 202

Digital Twins for Moving Target Defense Validation in AC Microgrids

Cyber-physical microgrids are vulnerable to stealth attacks that can degrade their stability and operability by performing low-magnitude manipulations in a coordinated manner. This paper formulates the interactions between CSAs and microgrid defenders as a non-cooperative, zero-sum game. Additionally, it presents a hybrid Moving Target Defense (MTD) strategy for distributed microgrids that can dynamically alter local control gains to achieve resiliency against Coordinated Stealth Attacks (CSAs). The proposed strategy reduces the success probability of attack(s) by making system dynamics less predictable. The framework also identifies and removes malicious injections by modifying secondary control weights assigned to them. The manipulated signals are reconstructed using an Artificial Neural Network (ANN)-based Digital Twin (DT) to preserve stability. To guarantee additional immunity against instability arising from gain alterations, MTD decisions are also validated (via utility and best response computations) using the DT before actual implementation. The DT is also used to find the minimum perturbation that defenders must achieve to invalidate an attacker's knowledge effectively.</p

Effects of fatty acid esters on mechanical, thermal, microbial, and moisture barrier properties of carboxymethyl cellulose-based edible films

Fatty acid esters being biodegradable and environment friendly has been a sought-after class of molecule for various food grade applications. This work involves the incorporation of fatty acid esters namely cetyl-caprylate and cetyl-caprate in edible Carboxymethyl cellulose -based films. The esters were enzymatically synthesized by esterification of caprylic acid and capric acid respectively with cetyl alcohol at a molar ratio of 1:1, using Candida antarctica lipase B which was immobilized (10 % w/w) at 65 °C. Carboxymethyl cellulose films were prepared. To it, glycerol and by emulsification, cetyl-caprylate or cetyl-caprate esters were amalgamated. Film characterizations involved analysis of surface morphology, mechanical properties, and thermal properties. It was further characterized by X-Ray diffraction analysis, water vapor permeability, and moisture uptake. Barrier property carboxymethyl cellulose films showed significant improvement due to the incorporation of cetyl-caprylate or cetyl-caprate esters. However, when the film's melting point was measured, it was seen that glycerol influenced the thermal properties more prominently than cetyl-caprylate and cetyl-caprate esters. Thus, the addition of an optimized amount of glycerol and cetyl-caprylate or cetyl-caprate esters to the carboxymethyl cellulose films is required for improved mechanical strength and better thermal properties. Further, an antimicrobial well diffusion assay of both the esters established the antimicrobial property of the same, which thereby recommends the addition of the wax esters even more