Some Results and a Conjecture for Manna's Stochastic Sandpile Model

We present some analytical results for the stochastic sandpile model, studied earlier by Manna. In this model, the operators corresponding to particle addition at different sites commute. The eigenvalues of operators satisfy a system of coupled polynomial equations. For an L X L square, we construct a nontrivial toppling invariant, and hence a ladder operator which acting on eigenvectors of evolution operator gives new eigenvectors with different eigenvalues. For periodic boundary conditions in one direction, one more toppling invariant can be constructed. We show that there are many forbidden subconfigurations, and only an exponentially small fraction of all stable configurations are recurrent. We obtain rigorous lower and upper bounds for the minimum number of particles in a recurrent configuration, and conjecture a formula for its exact value for finite-size rectangles.Comment: 12 pages. 3 eps figures. Minor revision of text. Some typographical errors fixed. Talk given at StatPhys-Calcutta III, Jan. 1999. To appear in Physica

Safeguarding IoMT: Semi-automated Intrusion Detection System (SAIDS) for detecting multilayer attacks

The Internet of Medical Things (IoMT) plays a significant role in the healthcare system as it improves effectiveness and efficiency of treatment by continuously monitoring patients using smart home sensor and wearables (Fig. 1). IoMT devices are vulnerable to Multi-layer attacks that are exploiting multiple layers of IoMT architecture (Fig. 2). Denial-of-service (DoS) and Man-In-The-Middle (MITM) attacks, for instance, can target the three layers of the IoMT system and lead to serious consequences, such as theft of patients’ sensitive data and reputational damages [2]. This project aims to create a robust detection system for multilayer attacks using a Semi-automated Intrusion Detection System (SAIDS) for IoT devices. To achieve this aim, we have focused on the following objectives: • Explore a variety of feature selection algorithms. • Apply feature weighting. • Integrating human and machine learning approaches to work together. • Increase detection efficiency by utilizing significant features

Investigating the security issues of multi-layer IoMT attacks using machine learning techniques

The Internet of Medical Things (IoMT) plays a significant role in the healthcare system as it improves effectiveness and efficiency of treatment by continuously monitoring patients using smart home sensor and wearables (Fig. 1), early disease diagnosis using data collected from the Internet of Medical Things (IoMT) devices and assisting doctors in deciding the best treatment and acting immediately if necessary. Additionally, it helps to reduce the number of hospital visits, limiting carbon footprint.IoMT devices are vulnerable to Multi-layer attacks because most of these devices are resource-constrained and portable, which is why there is not that much implementation of security features in these devices and making them a prime target for intruders looking to steal patients’ sensitive information and healthcare records. Multi-layer attacks are a group of attacksexploiting multiple layers of IoMT architecture. Denial-of-service (DoS) and Man-In-The-Middle (MITM) attacks, for instance, can target the three layers of the IoMT system and lead to serious consequences, such as theft of patients’ sensitive data and reputational damages. The main aim of the project is to create a robust IDS for IoT devices

Chaos in Sandpile Models

We have investigated the "weak chaos" exponent to see if it can be considered as a classification parameter of different sandpile models. Simulation results show that "weak chaos" exponent may be one of the characteristic exponents of the attractor of \textit{deterministic} models. We have shown that the (abelian) BTW sandpile model and the (non abelian) Zhang model posses different "weak chaos" exponents, so they may belong to different universality classes. We have also shown that \textit{stochasticity} destroys "weak chaos" exponents' effectiveness so it slows down the divergence of nearby configurations. Finally we show that getting off the critical point destroys this behavior of deterministic models.Comment: 5 pages, 6 figure

Human Ecology, Process Philosophy and the Global Ecological Crisis

This paper argues that human ecology, based on process philosophy and challenging scientific materialism, is required to effectively confront the global ecological crisis now facing us

Sandpile Model with Activity Inhibition

A new sandpile model is studied in which bonds of the system are inhibited for activity after a certain number of transmission of grains. This condition impels an unstable sand column to distribute grains only to those neighbours which have toppled less than m times. In this non-Abelian model grains effectively move faster than the ordinary diffusion (super-diffusion). A novel system size dependent cross-over from Abelian sandpile behaviour to a new critical behaviour is observed for all values of the parameter m.Comment: 11 pages, RevTex, 5 Postscript figure

Prediction of a magnetic Weyl semimetal without spin-orbit coupling and strong anomalous Hall effect in the Heusler compensated ferrimagnet Ti2MnAl

We predict a magnetic Weyl semimetal in the inverse Heusler Ti2MnAl, a compensated ferrimagnet with a vanishing net magnetic moment and a Curie temperature of over 650 K. Despite the vanishing net magnetic moment, we calculate a large intrinsic anomalous Hall effect (AHE) of about 300 S/cm. It derives from the Berry curvature distribution of the Weyl points, which are only 14 meV away from the Fermi level and isolated from trivial bands. Different from antiferromagnets Mn3X (X= Ge, Sn, Ga, Ir, Rh, and Pt), where the AHE originates from the non-collinear magnetic structure, the AHE in Ti2MnAl stems directly from the Weyl points and is topologically protected. The large anomalous Hall conductivity (AHC) together with a low charge carrier concentration should give rise to a large anomalous Hall angle. In contrast to the Co-based ferromagnetic Heusler compounds, the Weyl nodes in Ti2MnAl do not derive from nodal lines due to the lack of mirror symmetries in the inverse Heusler structure. Since the magnetic structure breaks spin-rotation symmetry, the Weyl nodes are stable without SOC. Moreover, because of the large separation between Weyl points of opposite topological charge, the Fermi arcs extent up to 75% of the reciprocal lattice vectors in length. This makes Ti2MnAl an excellent candidate for the comprehensive study of magnetic Weyl semimetals. It is the first example of a material with Weyl points, large anomalous Hall effect and angle despite a vanishing net magnetic moment.Comment: 6 pages, 4 figure

Study of the Effects of Flow Conditions on the Performance of Corrosion inhibitors under CO2 Environment

PresentationMajor process safety incidents have been caused by corrosion all over the world. These incidents are usually related to loss of containment of highly flammable liquids or gases, causing severe damages to the environment, impacts on people and monetary losses. Despite the increasing knowledge in corrosion, efforts are still needed to understand different damage mechanisms and their control methods. This work focuses on the study of different flow parameters such as flow velocity in a brine solution saturated with CO2 in presence of a non-toxic corrosion inhibitor. The tests will be performed using a rotating cylinder electrode which is a well-defined apparatus to study changes in hydrodynamic conditions in a pipe. Electrochemical techniques such as Electrochemical Impedance Spectroscopy (EIS) coupled with surface images will be used to understand the behavior of the inhibitor under different flow velocities. The objective isto enhance the fundamental understanding of the damage mechanisms present in the in downstream processes of oil and gas industry. The experimental results from this work would allow developing a model describing the corrosion behavior