Consensus in the Presence of Multiple Opinion Leaders: Effect of Bounded Confidence

The problem of analyzing the performance of networked agents exchanging evidence in a dynamic network has recently grown in importance. This problem has relevance in signal and data fusion network applications and in studying opinion and consensus dynamics in social networks. Due to its capability of handling a wider variety of uncertainties and ambiguities associated with evidence, we use the framework of Dempster-Shafer (DS) theory to capture the opinion of an agent. We then examine the consensus among agents in dynamic networks in which an agent can utilize either a cautious or receptive updating strategy. In particular, we examine the case of bounded confidence updating where an agent exchanges its opinion only with neighboring nodes possessing 'similar' evidence. In a fusion network, this captures the case in which nodes only update their state based on evidence consistent with the node's own evidence. In opinion dynamics, this captures the notions of Social Judgment Theory (SJT) in which agents update their opinions only with other agents possessing opinions closer to their own. Focusing on the two special DS theoretic cases where an agent state is modeled as a Dirichlet body of evidence and a probability mass function (p.m.f.), we utilize results from matrix theory, graph theory, and networks to prove the existence of consensus agent states in several time-varying network cases of interest. For example, we show the existence of a consensus in which a subset of network nodes achieves a consensus that is adopted by follower network nodes. Of particular interest is the case of multiple opinion leaders, where we show that the agents do not reach a consensus in general, but rather converge to 'opinion clusters'. Simulation results are provided to illustrate the main results.Comment: IEEE Transactions on Signal and Information Processing Over Networks, to appea

Machine Learning for Detecting Malware in PE Files

The increasing number of sophisticated malware poses a major cybersecurity threat. Portable executable (PE) files are a common vector for such malware. In this work we review and evaluate machine learning-based PE malware detection techniques. Using a large benchmark dataset, we evaluate features of PE files using the most common machine learning techniques to detect malware

Fabrication of PECVD-grown fluorinated hydrocarbon nanoparticles and circular nanoring arrays using nanosphere lithography

Nanosphere lithography (NSL) masks were created by spin-coating of polystyrene particles onto silicon surfaces. Fluorinated hydrocarbon films were coated on the nanosphere lithography masks using plasma-enhanced chemical vapor deposition (PECVD) to obtain ordered arrays of fluorinated hydrocarbon. Atomic force microscope images show hexagonally ordered nanodots of dimension 225 ± 11 nm with a height of 23 ± 4 nm. Every hexagon encloses a circular ring of diameter 540 ± 24 nm having a height and width of 13.5 ± 0.6 nm and 203 ± 16 nm, respectively. FTIR analysis shows two distinct zones of atomic bonding of CHx and CFx in the plasma coated ordered fluorinated hydrocarbon films

Superhydrophobic coatings with reduced ice adhesion

A brief description of how superhydrophobicity can help mitigate the ice accretion problem on power network equipment and other exposed structures by reducing ice-to-surface adhesion is presented. Basic models, namely the Wenzel and Cassie–Baxter models, accounting for the contact angle of water on solid surfaces relating to the influence of surface roughness on hydrophobicity are discussed. The results on superhydrophobic aluminum surfaces, superhydrophobic nanostructured silver thin films, superhydrophobic nanostructured zinc oxide as well as superhydrophobic nanofibres are also discussed. Some of the superhydrophobic surfaces were tested for ice adhesion and a reduced ice adhesion was obtained

One-Step Deposition Process to Obtain Nanostructured Superhydrophobic Thin Films by Galvanic Exchange Reactions

Superhydrophobic thin films of silver were fabricated on copper substrates by galvanic ion exchange reactions in a one-step process by immersing copper substrates in silver nitrate solution containing fluoroalkylsilane in different quantities. The X-ray diffraction (XRD) analyses confirmed the formation of silver films on copper substrates and the fractal-like morphological features of the silver films were confirmed using scanning electron microscopy (SEM). The contact angle of water on these surfaces is found to be greater than 165°, demonstrating water repellency with water drops rolling off the surfaces. The X-ray photoelectron spectroscopy (XPS) depth profile confirms the presence of fluorine in the silver films

Parallel Parsing in a Multiprocessor Environment

Parsing in a multiprocessor environment is considered. Two models for asynchronous bottom-up parallel parsing are presented. A method for estimating speedup in asynchronous bottom-up parallel parsing is developed, and it is used to estimate speedup obtainable by bottom-up parallel parsing of Pascal-like languages. It is found that bottom-up parallel parsing algorithms can attain a maximum speedup of 0 (L1/2) with (L1/2) processors, where L is the number of tokens in the string being parsed. Hence, bottom-up parallel parsing technique does not yield good speedup. A new parsing technique is proposed for parsing a class of block-structured languages. The novelty of the technique is that it is inherently parallel. By applying this new technique, a string of L tokens can be parsed in O (log L) time with (L /log L) processors. The parsing algorithm uses a parenthesis-matching algorithm developed here. The parenthesis-matching algorithm can find matching of a sequence of parentheses in O (log L) time with (L /log L) processors. Thus, the new parsing algorithm is cost optimal

Superhydrophobic properties of silver-coated films on copper surface by galvanic exchange reaction

Hydrophobic properties of thin nanostructured silver films produced by galvanic exchange reaction on a copper surface were studied after passivation with stearic acid. The morphology of the silver films was controlled by varying the concentration of silver nitrate in the solution. Water contact angle as high as 156° and contact angle hystérésis as low as 5° were achieved for samples obtained with initial silver ion concentration of 24.75 mM in the solution. However, a strong dependence of contact angle and contact angle hysteresis on the fractal-like morphology of the silver films was observed with the variation of silver ion concentration