Mechanism Of Attack Research Articles

An Effective and Secure Mechanism for Phishing Attacks Using a Machine Learning Approach

Phishing is one of the biggest crimes in the world and involves the theft of the user’s sensitive data. Usually, phishing websites target individuals’ websites, organizations, sites for cloud storage, and government websites. Most users, while surfing the internet, are unaware of phishing attacks. Many existing phishing approaches have failed in providing a useful way to the issues facing e-mails attacks. Currently, hardware-based phishing approaches are used to face software attacks. Due to the rise in these kinds of problems, the proposed work focused on a three-stage phishing series attack for precisely detecting the problems in a content-based manner as a phishing attack mechanism. There were three input values—uniform resource locators and traffic and web content based on features of a phishing attack and non-attack of phishing website technique features. To implement the proposed phishing attack mechanism, a dataset is collected from recent phishing cases. It was found that real phishing cases give a higher accuracy on both zero-day phishing attacks and in phishing attack detection. Three different classifiers were used to determine classification accuracy in detecting phishing, resulting in a classification accuracy of 95.18%, 85.45%, and 78.89%, for NN, SVM, and RF, respectively. The results suggest that a machine learning approach is best for detecting phishing.

A Review: Antibacterial Activity of Metal Impregnated Zeolite in Water Treatment Process

Environmental and health problems related to water pollution by bacteria are a big challenge in the water treatment process. This pollution is caused by industrial development and increased population growth. Bacterial removal methods in water are continuously developed to find an efficient water treatment process. Zeolite has the potential to be an adsorbent used in the water treatment process. Zeolite has been widely used in adsorption and catalytic processes. Zeolite is a porous alumina silicate consisting of silicon, aluminium, and oxygen in its framework. Zeolite cations can be exchanged with monovalent or divalent ions. Zeolite does not have antibacterial activity, so it should combine with metal cations such as Ag, Cu, Zn, and Fe. Metal active that loaded into zeolite framework is a solution to improve the zeolite performance for bacteries removing in water. The impregnation method is the most widely used for the metal loading process into zeolite framework, because of its simple and economical process. This review will discuss natural and synthetic zeolites, types of metal, impregnation process, the antibacterial activity of metal impregnated zeolite, bacterial attack mechanism, and antibacterial application of metal impregnated zeolite in water

A comparative evaluation of waste wood and herbaceous biomass fireside corrosion behaviours

Biomass/biomass waste (BBW) is a renewable energy source fired in combustion power plants. However, challenges associated include accelerated ‘fireside’ corrosion of heat exchangers. Fireside corrosion is fuel dependent, e.g. virgin wood fuels have lower fireside corrosion risks; as such their demand and cost is high. Waste wood fuels (WWF) and herbaceous grass biomass (HGB), generate different combustion environments, influencing heat exchanger fireside corrosion damage.This paper compares the fireside corrosion of WWF and HGB fuels to improve understanding of their attack mechanisms on T91 and 374HFG. The species generated in combustion have been investigated by thermodynamic modelling. Corrosion damage has been evaluated by high temperature corrosion furnace tests at 600 °C, employing the well-established deposit recoat method based on these evolved species. Vapour condensation fluxes have been compared for both fuel categories; corrosion rates increase with this condensation flux. Deposition fluxes from HGB fuels are higher than for WWF. For example, the average KCl deposition fluxes calculated are 1566 µg/cm2h and 295 µg/cm2h per kg fuel feed respectively, explaining the comparatively greater fireside corrosion rates experienced in power plants combusting HGB fuels. The deposit chemistries generated are also different: K-containing compounds only (for HGB fuels) versus K-, Na- and Ca-containing compounds (for WWF).Evaluation of corroded samples exposed to the different deposit chemistries show increased corrosion attack to both steels under simulated WWF firing conditions than for the HGB at matched deposit flux (100 µg/cm2h).

Benchmark Ab Initio Characterization of the Abstraction and Substitution Pathways of the Cl + CH3CN Reaction.

We investigate the reaction pathways of the Cl + CH3CN system: hydrogen abstraction, methyl substitution, hydrogen substitution, and cyanide substitution, leading to HCl + CH2CN, ClCN/CNCl + CH3, ClCH2CN + H, and CH3Cl + CN, respectively. Hydrogen abstraction is exothermic and has a low barrier, whereas the other channels are endothermic with high barriers. The latter two can proceed via a Walden inversion or front-side attack mechanism, and the front-side attack barriers are always higher. The C-side methyl substitution has a lower barrier and also a lower endothermicity than the N-side reaction. The computations utilize an accurate composite ab initio approach and the explicitly correlated CCSD(T)-F12b method. The benchmark classical and vibrationally adiabatic energies of the stationary points are determined with the most accurate CCSD(T)-F12b/aug-cc-pVQZ energies adding further contributions of the post-(T) and core correlation, scalar relativistic effects, spin–orbit coupling, and zero-point energy corrections. These contributions are found to be non-negligible to reach subchemical accuracy.

Sulfuric acid and citric acid attack of calcium sulfoaluminate-based binders

Calcium sulfoaluminate (CSA) cement-based binders are low CO2 binders which exhibit rapid hardening or shrinkage compensating characteristics. Due to their unique properties, they have potential to be used in concrete elements exposed to acidic environment such as sewage system. In this paper, the performance of CSA-based binders in acidic environment is examined and compared against Portland cement (PC). Attack of sulfuric acid and citric acid on PC and CSA-based binders was evaluated with respect to mass loss, dimensional change, cumulative H+ ion neutralisation, strength loss, and changes in mineralogical and microstructural characteristics. CSA-based binder exhibited higher resistance than PC-dominated binder in citric acid attack (pH ∼ 2–3), whereas PC-dominated binder outperformed CSA-based binder in case of sulfuric acid attack (pH ∼ 1.5–2). The mechanism of acid attack was found to be dependent on acid type. A calcium citrate salt was identified as the major product in case of citric acid attack of PC-dominated binders.

Mitigation of black hole attacks in 6LoWPAN RPL-based Wireless sensor network for cyber physical systems

A cyber–physical system (CPS) classically comprises the physical components, computational units, the controller, and the communication network. The Wireless sensor networks (WSNs) is a key component in the CPS and connects the distributed sensors for computation and communication. As the usage of such networks increases, the attack surface also increases and mechanisms for mitigating security threats must be developed. The nodes in the WSN are low-powered devices that cannot host traditional security systems. Moreover, specialized architectures of such networks mean that new attacks specifically targeting such architectures would be discovered. The proposed work introduces a security mechanism for black hole attack in Ripple Routing Protocol (RPL) networks, utilizing features such as IPv6 over Low-Power Wireless Personal Area Networks (6LoWPAN) network discovery. The state-of-the-art mechanisms existing today for such threats are either heavyweight intrusion detection systems or require nodes working in promiscuous mode. The promiscuity of nodes can be a security concern in itself, whereas large intrusion detection systems require huge processing and network overheads. The proposed work does not rely on either but utilizes a distributed timer-based mechanism to perform malicious node detection. The work has been evaluated using the Cooja simulator, and it has been seen that it can detect black holes with high accuracy resulting in a decrease in packet loss. The true positive rate can reach up to 100%.

Gut Microbiome and Metabolomics Profiles of Allergic and Non-Allergic Childhood Asthma.

PurposeThis study aimed to investigate the characteristics of gut bacteria and the derived metabolites among allergic asthmatic children, non-allergic asthmatic children and healthy children without asthma.MethodsFecal samples were collected from 57 participants, including 20 healthy children, 27 allergic asthmatic children, and 10 non-allergic asthmatic children. 16S rRNA gene sequencing was conducted for analyzing gut bacterial compositions and untargeted metabolomics was used to analyze the alterations of gut microbe-derived metabolites. The associations between gut bacterial compositions and metabolites were analyzed by the method of Spearman correlation.ResultsThe results showed that the compositions and metabolites of gut microbiome were altered both in allergic and non-allergic asthmatics compared with healthy controls. Chao1 (p = 0.025) index reflected a higher bacterial richness and Simpson (p = 0.024) index showed a lower diversity in asthma group. PERMANOVA analysis showed significant differences among the three groups based on unweighted UniFrac distance (p = 0.001). Both allergic and non-allergic asthmatics showed a higher relative abundance of Proteobacteria and a lower relative abundance of genera from Clostridia. More bacteria were altered in non-allergic asthmatics compared with allergic asthmatics. Metabolomics analysis identified that 42 metabolites were significantly associated with allergic asthma, and 58 metabolites were significantly associated with non-allergic asthma (multiple linear regression, p < 0.05). Histamine was 4 folds up-regulated only in the non-allergic asthma group. The relative abundance of Candidatus Accumulib was significantly correlated with the upregulation of histamine. The relative abundance of genera from Clostridia was significantly correlated with the downregulation of lipid and tryptophan metabolism.ConclusionThe altered gut microbes was associated with the mechanism of asthma attack through metabolites in allergic and non-allergic asthma group, respectively. The result suggested that gut microbiome had an impact on the development of both allergic and non-allergic asthma. The distinct gut microbiome and microbiome-derived metabolites in non-allergic asthma children suggested that gut microbiome might play a critical role in modulation of asthma phenotype.

Network optimization using defender system in cloud computing security based intrusion detection system withgame theory deep neural network (IDSGT-DNN)

Cloud computing leads an organization for data storage, sharing, processing, and other services. It was subjected to several challenges insecurity due to the presence of regular attacks. These security challenges are worsened due to the presence of various attack environments. The conventional techniques adopted in cloud security are Intrusion Detection System (IDS). However, the IDS system requires an efficient security model for improving security in the cloud. In this paper, to improve the security in the cloud IDS system developed a framework stated as IDSGT-DNN. The proposed model incorporates an attacker and a defender mechanism for attack and normal data processing. The developed game theory is implemented in the DNN model with IWA for the identification of optimal solutions. The estimation is based on the identification of minimal and maximal optimal points in the dataset. The proposed IDSGT-DNN model is evaluated for CICIDS - 2017 dataset. The performance of proposed IDSGT-DNN is evaluated with existing technique is performed. Simulation analysis exhibited that proposed IDSGT-DNN exhibits enhanced performance in terms of accuracy, detection rate, and precision, F-Score, AUC, and FPR.

Adversarial Attack and Defence Strategies for Deep-Learning-Based IoT Device Classification Techniques

Concurrent advancements in machine learning (ML) and Internet of Things have allowed several interesting interdisciplinary applications, such as classification tasks based on data generated by smart devices for applications, such as security, resource allocation, activity and task classification. However, these applications can be vulnerable to attacks by adversarial examples. The first contribution of this article is the development of a white-box adversarial attack mechanism to generate adversarial examples for data obtained from smart meters installed in residential houses. For the second contribution, we present an analysis to demonstrate that the statistical properties of adversarial datapoints are indistinguishable from those of the true datapoints. The attack is developed specifically for deep-learning-based models used to perform appliance classification in smart home environments. The statistical indistinguishability of the adversarial datapoints from the true datapoints indicates that non ML-based solutions may not be able to tackle the challenge posed by adversarial examples. As the final contribution, we evaluate the effectiveness of defence mechanisms for white-box adversarial attacks on the proposed attack mechanism, and show that while they can reduce the potency of the attack, the original models still remain significantly affected by the adversarial attack. The effectiveness of the proposed techniques is demonstrated on two publicly available data sets: 1) United Kingdom-domestic appliance-level electricity smart meter data set and 2) the Personalized Retrofit Decision Support Tools For U.K. Homes Using Smart Home Technology data set.

Corrosion failure analysis of a cooling system of an injection mold

High-pressure injection molding is an important industrial process, which requires a precise cooling stage. In this work, we analyzed the reasons for the corrosion failure of the cooling circuit of molds in the molding plant. The cooling circuit was inspected visually and collected samples were further analyzed in a laboratory using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The main problems were an improper selection of the antibacterial agent and materials of the cooling circuit. Based on the performed analyses, a possible mechanism of the corrosion attack was proposed and recommendations to decrease the number of corrosion-related failures and services were formulated.

Electrocatalytic Water Oxidation Activity of Molecular Copper Complexes: Effect of Redox-Active Ligands.

Two molecular copper(II) complexes, (NMe4)2[CuII(L1)] (1) and (NMe4)2[CuII(L2)] (2), ligated by a N2O2 donor set of ligands [L1 = N,N'-(1,2-phenylene)bis(2-hydroxy-2-methylpropanamide), and L2 = N,N'-(4,5-dimethyl-1,2-phenylene)bis(2-hydroxy-2-methylpropanamide)] have been synthesized and thoroughly characterized. An electrochemical study of 1 in a carbonate buffer at pH 9.2 revealed a reversible copper-centered redox couple at 0.51 V, followed by two ligand-based oxidation events at 1.02 and 1.25 V, and catalytic water oxidation at an onset potential of 1.28 V (overpotential of 580 mV). The electron-rich nature of the ligand likely supports access to high-valent copper species on the CV time scale. The results of the theoretical electronic structure investigation were quite consistent with the observed stepwise ligand-centered oxidation process. A constant potential electrolysis experiment with 1 reveals a catalytic current density of >2.4 mA cm-2 for 3 h. A one-electron-oxidized species of 1, (NMe4)[CuIII(L1)] (3), was isolated and characterized. Complex 2, on the contrary, revealed copper and ligand oxidation peaks at 0.505, 0.90, and 1.06 V, followed by an onset water oxidation (WO) at 1.26 V (overpotential of 560 mV). The findings show that the ligand-based oxidation reactions strongly depend upon the ligand's electronic substitution; however, such effects on the copper-centered redox couple and catalytic WO are minimal. The energetically favorable mechanism has been established through the theoretical calculation of stepwise reaction energies, which nicely explains the experimentally observed electron transfer events. Furthermore, as revealed by the theoretical calculations, the O-O bond formation process occurs through a water nucleophilic attack mechanism with an easily accessible reaction barrier. This study demonstrates the importance of redox-active ligands in the development of molecular late-transition-metal electrocatalysts for WO reactions.

Systematic Influence of Electronic Modification of Ligands on the Catalytic Rate of Water Oxidation by a Single-Site Ru-Based Catalyst.

Catalytic water oxidation is an important process for the development of clean energy solutions and energy storage. Despite the significant number of reports on active catalysts, systematic control of the catalytic activity remains elusive. In this study, descriptors are explored that can be correlated with catalytic activity. [Ru(tpy)(pic)2 (H2 O)](NO3 )2 and [Ru(EtO-tpy)(pic)2 (H2 O)](NO3 )2 (where tpy=2,2' : 6',2"-terpyridine, EtO-tpy=4'-(ethoxy)-2,2':6',2"-terpyridine, pic=4-picoline) are synthesized and characterized by NMR, UV/Vis, EPR, resonance Raman, and X-ray absorption spectroscopy, and electrochemical analysis. Addition of the ethoxy group increases the catalytic activity in chemically driven and photocatalytic water oxidation. Thus, the effect of the electron-donating group known for the [Ru(tpy)(bpy)(H2 O)]2+ family is transferable to architectures with a tpy ligand trans to the Ru-oxo unit. Under catalytic conditions, [Ru(EtO-tpy)(pic)2 (H2 O)](NO3 )2 displays new spectroscopic signals tentatively assigned to a peroxo intermediate. Reaction pathways were analyzed by using DFT calculations. [Ru(EtO-tpy)(pic)2 (H2 O)](NO3 )2 is found to be one of the most active catalysts functioning by a water nucleophilic attack mechanism.

Hydrogen atom abstraction mechanism for organic compound oxidation by acetylperoxyl radical in Co(II)/peracetic acid activation system

Peracetic acid (PAA) has been widely used as an alternative disinfectant in wastewater treatment, and PAA-based advanced oxidation processes (AOPs) have drawn increasing attention recently. Among the generated reactive species after PAA activation, acetylperoxyl radical (CH3CO3•) plays an important role in organic compounds degradation. However, little is known about the reaction mechanism on CH3CO3• attack due to the challenging of experimental analysis. In this study, a homogeneous PAA activation system was built up using Co(II) as an activator at neutral pH to generate CH3CO3• for phenol degradation. More importantly, reaction mechanism on CH3CO3•-driven oxidation of phenol is elucidated at the molecular level. CH3CO3• with lower electrophilicity index but much larger Waals molecular volume holds different phenol oxidation route compared with the conventional •OH. Direct evidences on CH3CO3• formation and attack mechanism are provided through integrated experimental and theoretical results, indicating that hydrogen atom abstraction (HAA) is the most favorable route in the initial step of CH3CO3•-driven phenol oxidation. HAA reaction step is found to produce phenoxy radicals with a low energy barrier of 4.78 kcal mol−1 and free energy change of -12.21 kcal mol−1. The generated phenoxy radicals will undergo further dimerization to form 4-phenoxyphenol and corresponding hydroxylated products, or react with CH3CO3• to generate catechol and hydroquinone. These results significantly promote the understanding of CH3CO3•-driven organic pollutant degradation and are useful for further development of PAA-based AOPs in environmental applications.

Resolving the conflict between antibiotic production and rapid growth by recognition of peptidoglycan of susceptible competitors

Microbial communities employ a variety of complex strategies to compete successfully against competitors sharing their niche, with antibiotic production being a common strategy of aggression. Here, by systematic evaluation of four non-ribosomal peptides/polyketide (NRPs/PKS) antibiotics produced by Bacillus subtilis clade, we revealed that they acted synergistically to effectively eliminate phylogenetically distinct competitors. The production of these antibiotics came with a fitness cost manifested in growth inhibition, rendering their synthesis uneconomical when growing in proximity to a phylogenetically close species, carrying resistance against the same antibiotics. To resolve this conflict and ease the fitness cost, antibiotic production was only induced by the presence of a peptidoglycan cue from a sensitive competitor, a response mediated by the global regulator of cellular competence, ComA. These results experimentally demonstrate a general ecological concept – closely related communities are favoured during competition, due to compatibility in attack and defence mechanisms.

Association Between Preinfarction Angina and Culprit Lesion Morphology in Patients With ST-Segment Elevation Myocardial Infarction: An Optical Coherence Tomography Study.

BackgroundPrevious studies reported the cardiac protection effect of preinfarction angina (PIA) in patients with acute myocardial infarction (AMI). We sought to identify culprit-plaque morphology and clinical outcomes associated with PIA in patients with ST-segment elevation myocardial infarction (STEMI) using optical coherence tomography (OCT).Methods and ResultsA total of 279 patients with STEMI between March 2017 and March 2019 who underwent intravascular OCT of the culprit lesion were prospectively included. Of them, 153 (54.8%) patients were presented with PIA. No differences were observed in clinical and angiographic data between the two groups, except STEMI onset with exertion was significantly less common in the PIA group (24.2 vs. 40.5%, p = 0.004). Patients with PIA exhibited a significantly lower incidence of plaque rupture (40.5 vs. 61.9%, p < 0.001) and lipid-rich plaques (48.4 vs. 69.0%, p = 0.001). The thin-cap fibroatheroma (TCFA) prevalence was lower in the PIA group, presenting a thicker fibrous cap thickness, although statistically significant differences were not observed (20.3 vs. 30.2%, p = 0.070; 129.1 ± 92.0 vs. 111.4 ± 78.1 μm, p = 0.088; respectively). The multivariate logistic regression analysis indicated that PIA was an independent negative predictor of plaque rupture (odds ratio: 0.44, 95% CI: 0.268–0.725, p = 0.001). No significant differences in clinical outcomes were observed besides unplanned revascularization.ConclusionCompared with the non-PIA group, STEMI patients with PIA showed a significantly lower prevalence of plaque rupture and lipid-rich plaques in culprit lesion, implying different mechanisms of STEMI attack in these two groups.

Understanding the acrylates formation from CO2 and ethylene over Ni- and Pd-based catalysts: A DFT study on the effects of solvents, methyl halides, and ligands

In this work, two methylation reaction pathways were investigated to explore the role of solvent and I− on the formation of methyl acrylate from coupling of CO2 and ethylene catalyzed by nickel and palladium catalysts in the presence of MeI. The stabilization of non-productive intermediates is inhibited in the gas phase as well as in low-polar solvents, which explains the requirement of high excess of MeI to obtain high yields of methyl acrylate. The energy barrier for M-O bond cleavage as well as the stability of the overall reaction intermediates is consistent with the corresponding halogen electron-donating ability. The different catalytic behaviors of various bidentate ligands on Ni- and Pd-based catalysts were systematically investigated, mainly including dmpe(1,2-bis(dimethylphosphino)ethane), tmeda(tetramethylethylenediamine), dppe(1,2-bis(diphenylphosphino)ethane), dcpe(1,2-bis(dicyclohexylphosphino)ethane) and dtbpe(1,2-bis(di-tert-butylphosphino)ethane). The energy barrier of M-O bond cleavage increases with the enhancement of ligand steric hindrance in the O1 (ester sp3 O atom) attack mechanism, while the corresponding O2 (carboxylic sp2 O atom) attack mechanism shows an opposite trend. The energy barrier of β-H elimination in both catalytic systems is strongly related to the electron-donating ability of the diphosphine ligand substituents. The dcpp(1,3-bis(dicyclohexylphosphino)propane) ligand shows relatively good performance for β-H elimination among all the investigated ligands in Pd-mediated system. In general, diphosphine ligands are superior to diamine ligands in Pd-mediated system in terms of efficiency.

Logic Locking Using Emerging 2T/3T Magnetic Tunnel Junctions for Hardware Security

With the advancement of beyond CMOS devices, a new approach to utilize the inherent physics of such emerging structures for various applications is of great interest in recent research. Spintronics-based devices offer key advantages like ease of fabrication with Si-substrate, non-volatile memory, low operational voltage, and non-linear device characteristics, which have shown potential for several emerging fields of study. Hardware security is one of the key interest areas which heavily relies on CMOS-based ICs, and the defense and attack mechanism is mostly based on CMOS-based structures. This work explores several emerging structures based on 2T/3T magnetic tunnel junctions (MTJ) for possible logic locking applications in hardware security systems. We demonstrate the effect of MTJ-based devices to implement logic locking even in the presence of process variations, and its ability of robustness to device imperfections has been evaluated using monte carlo simulations for practical applications.

Cerebral venous hemodynamics and venous blood flow reactivity in patients with migraine

Introduction. Headache is currently one of the most common complaints in various pathological conditions. At the present level, the use of transcranial duplex scanning (TDS) in the diagnosis of various types of headache is relevant. Recently, a sufficiently large number of works have been published on the study of cerebral hemodynamic disorders in patients with migraine with and without aura, in the interictal period and during an attack. The ample data support the vascular hypothesis of migraine pathogenesis. Studies of venous cerebral hemodynamics have also been conducted in patients with migraine. The relationship between the severity of venous disorders and the state of vascular tone was revealed. Cerebrovascular reactivity (CVR) is considered as an integral indicator of the adaptive capabilities of the cerebral circulatory system. The use of TDS to assess CVR is informative in patients with migraine. The aim of the study was to assess the state of the cerebral venous hemodynamics and regulation cerebral venous blood flow in patients with migraine. Materials and methods. We performed clinical Doppler examination of 124 young patients (55 men, 69 women) with migraine without aura (group 1 – 63 patients), migraine with aura (group 2 – 61 patients). The TDS method was used to study indicators maximum linear speed blood flow (Vmax) in the supraocular (SOV) and vertebral (VV) veins, basal veins of Rosenthal (BV), direct sinus (DS), as well as reactivity coefficients in DS and BV using hypercapnic, orthostatic, antiorthostatic loads. Results. Patients of the 1st group were characterized by hyporeactivity in DS and BV to hypercapnic load, as a sign of primary venous angiodystonia. Also hyperreactivity of these patients to antiorthostatic load in PS and BV was revealed, as an indicator of dysfunction of the neurogenic regulation circuit. The patients of the 2nd group showed a combined hyperreactivity in DS and BV to hypercapnic and antiorthostatic loads, as a sign of dysfunction of the neurogenic circuit of vascular regulation. Conclusions. Cerebral venous hemodynamic changes in patients with migraine in the interictal period are manifested as disorders of cerebral venous blood flow in the superocular veins, basal veins of Rosenthal and direct sinus, more pronounced in the migraine with aura group. Patients with migraine without aura are characterized by hyporeactivity in DS and BV to hypercapnic load and hyperreactivity to antiorthostatic load in PS and BV. In patients with migraine with aura, hyperreactivity in PS and BV to hypercapnic and antiorthostatic loads is observed. The use of Doppler study of cerebral venous hemodynamics and reactivity of venous cerebral blood flow makes it possible to clarify the pathogenetic mechanisms of a migraine attack and helps to optimize the treatment of patients with migraine, taking into account the state of cerebral vascular regulation.

Unidirectional Penetration Approach for Characterizing Sulfate Attack Mechanisms on Cement Mortars and Pastes

Unidirectional Penetration Approach for Characterizing Sulfate Attack Mechanisms on Cement Mortars and Pastes

Optimal stealthy attack against stochastic event‐based scheduling for remote state estimation in cyber‐physical systems

AbstractThis article concentrates on security issues of stochastic event‐based (SEB) sensor scheduling in cyber‐physical systems (CPSs). An SEB attack mechanism is proposed to compromise remote state estimation, in which the attacker can jam the feedback channel and inject false acknowledgments. Based on the Gaussian assumption, the minimum mean square error estimator under the SEB attack is obtained utilizing Bayes' theorem. In this article, the SEB attack stealthiness is composed of communication ratio invariance and anomaly detection invisibility with the forward channel. Furthermore, a double stealthy attack condition is given to complete persistent attacks from the perspective of the attacker. Aiming at maximizing average error covariances on the remote estimator, we design a generation algorithm of optimal SEB stealthy attack sequence and prove its optimality by rearrangement inequality and mathematical induction. Finally, the scalar and networked dc motor vector system simulations illustrate the corresponding theoretical results.