Processor array architectures for deep packet classification

This paper presents a systematic technique for expressing a string search algorithm as a regular iterative expression to explore all possible processor arrays for deep packet classification. The computation domain of the algorithm is obtained and three affine scheduling functions are presented. The technique allows some of the algorithm variables to be pipelined while others are broadcast over system-wide buses. Nine possible processor array structures are obtained and analyzed in terms of speed, area, power, and I/O timing requirements. Time complexities are derived analytically and through extensive numerical simulations. The proposed designs exhibit optimum speed and area complexities. The processor arrays are compared with previously derived processor arrays for the string matching problem.     

Developing a Model of Construction Safety Culture

The concept of safety culture is relatively new in the construction industry; however, it is gaining popularity due to its ability to embrace all perceptional, psychological, behavioral, and managerial factors. To address the lack of a verifiable process to analyze construction safety culture, this technical note presents a robust conceptual model that has its roots firmly entrenched in pertinent academic and applied literature. It provides a critical review of the term “safety culture”; along with distinct yet related concepts (i.e., safety climate, behavior-based safety, and safety system). It also compares the proposed model with available safety culture models in order to demonstrate its applicability in construction site environments.     

Thermal analysis of dielectric insulation,ethylene/propylene rubbers,and cross-linked polyethylenes decomposed in a nitrogen atmosphere

The techniques of thermogravimetric and derivative thermogravimetric analyses have been applied to the determination of temperatures and heats of decompositions of four ethylene/propylene rubbers and seven cross-linked polyethylenes in nitrogen. These materials are commonly used in the wire and ruble industry as dielectric insulation. The polymers were found to decompose in at least three overlapping stages. Each stage has an activation energy characteristic of the process. Differential thermal analysis was significantly less useful in this study due to the conflict of the endothermal heat of vaporization and the exothermal heat of decomposition.     

Temporal validation of multimedia protocols

With the emergence of distributed multimedia systems, temporal constraints are becoming a fundamental feature in specifying and validating distributed systems. We have already developed an approach for specifying and validating end-to-end protocols with temporal constraints. The method based on reachability analysis, consists in constructing a temporal reachability graph describing the communication between two temporal machines through two temporal FIFO channels. The structure and states of this graph are then studied according to given communication properties to validate the related protocol. In this paper, we show how to genera lize this model for describing and validating multimedia protocols that are generally made up of more than two temporal machines communicating either through temporal FIFO channels or by rendezvous. Two examples of such protocols are considered as case studies.     

Numerical Analysis of Novel Coronavirus (2019-nCov) Pandemic Model with Advection

Recently, the world is facing the terror of the novel corona-virus, termed as COVID-19. Various health institutes and researchers are continuously striving to control this pandemic. In this article, the SEIAR (susceptible, exposed, infected, symptomatically infected, asymptomatically infected and recovered) infection model of COVID-19 with a constant rate of advection is studied for the disease propagation. A simple model of the disease is extended to an advection model by accommodating the advection process and some appropriate parameters in the system. The continuous model is transposed into a discrete numerical model by discretizing the domains, finitely. To analyze the disease dynamics, a structure preserving non-standard finite difference scheme is designed. Two steady states of the continuous system are described i.e., virus free steady state and virus existing steady state. Graphical results show that both the steady states of the numerical design coincide with the fixed points of the continuous SEIAR model. Positivity of the state variables is ensured by applying the M-matrix theory. A result for the positivity property is established. For the proposed numerical design, two different types of the stability are investigated. Nonlinear stability and linear stability for the projected scheme is examined by applying some standard results. Von Neuman stability test is applied to ensure linear stability. The reproductive number is described and its pivotal role in stability analysis is also discussed. Consistency and convergence of the numerical model is also studied. Numerical graphs are presented via computer simulations to prove the worth and efficiency of the quarantine factor is explored graphically, which is helpful in controlling the disease dynamics. In the end, the conclusion of the study is also rendered.     

Validation of protocols with temporal constraints

Reachability analysis is the most popular and most used method in protocol validation. It consists in constructing a graph called a reachability graph, describing communication of machines exchanging messages through FIFO channels. The states and structure of this graph are then analysed according to given properties to validate the related communication protocol. In this paper, we deal with a generalization of reachability analysis to take into account quantitative temporal constraints in protocol validation. A temporal reachability graph is designed, and we show how it can be used to analyse new general properties of communication protocols submitted to temporal constraints.     

Investigations of novel nitrile-based ionic liquids as pre-treatment solvent for extraction of lignin from bamboo biomass

In this work, nitrile-based ionic liquids (ILs) i.e., 1-propyronitrile-3-butylimidazolium chloride [C2CNBim]Cl, 1-propyronitrile-3-allylimidazolium chloride [C2CNAim]Cl, 1-propyronitrile-3-(2-hydroxyethyl)imidazolium chloride [C2CN HEim]Cl and 1-propyronitrile-3-benzyllimidazolium chloride [C2CN Bzim]Cl were used as pre-treatment solvent for the extraction of lignin from bamboo biomass. The pre-treatment process was investigated with respect to several factors such as the types of ionic liquid cation used, the effect of pretreatment temperature and time, sample loading and particle size, the effect of recycling the ionic liquid on lignin extraction and the effect of multi-extraction to enhance the recovery of lignin which were collectively found to have an impact on the lignin extraction as a whole. The crystallinity of the cellulose-rich material obtained from the extraction was analyzed using XRD while the extracted lignin was characterized using FTIR, NMR, TGA and elemental analysis. From the XRD analysis, the crystallinity of the cellulose-rich material obtained after treatment with the synthesized nitrile-based ILs was found to remain the same. Among the nitrile-based ILs used, [C2CN Bzim]Cl demonstrate the best performance for the extraction process in a predetermined condition (T = 120 °C, t = 24 h) where 53% of the lignin from the bamboo was successfully extracted. This was confirmed from the FTIR and NMR analysis showing the characteristic peaks indicating the presence of lignin in the spectra of the respective samples tested.     

Electrospun titanium dioxide nanofiber humidity sensors with high sensitivity

Titanium dioxide nanofibers were synthesized using electrospinning technique. The nanofibers were porous with an average diameter and length of ～150 nm and 200 μm, respectively. Humidity-sensing devices were fabricated by lithographically defined aluminum electrodes on top of the nanofibers deposited on silicon dioxide grown thermally on a silicon substrate. The performance of a TiO₂ nanofiber humidity sensor was tested by AC and DC electrical measurements at 40–90% relative humidity. The response and the recovery time were 1 s and 4 s, respectively, between 40% and 90% relative humidity. The sensitivity of the TiO₂ humidity sensor in the range of 40–90% RH was 150 MΩ/%RH and 20 MΩ/%RH at 10 Hz and 100 Hz, respectively. The excellent sensing characteristics are attributed to the porous nature and the small diameter of the nanofibers.     

Sulfate-vanadate hot corrosion of neodymium cerate/yttria stabilized zirconia composite coating

Neodymium cerate (Nd₂Ce₂O₇) was laboratory synthesized by solid-state reactions of neodymia and ceria and spray dried to get the feedstock for plasma spraying. Hot corrosion behavior of air plasma sprayed 10% Nd₂Ce₂O₇/yttria stabilized zirconia (YSZ) topcoat was studied in the presence of V₂O₅ and Na₂SO₄ salts at 950°C for 10-60 hours. It was observed that due to the presence of relatively higher basic compounds Nd₂O₃ and CeO₂ (form Nd₂Ce₂O₇) than Y₂O₃ in YSZ changed the reaction dynamics during hot corrosion and the major part of corrosive (NaVO₃) was consumed by Nd of Nd₂Ce₂O₇, making NdVO₄. The Y₂O₃ of YSZ contributed in the corrosive reaction partially, relieving majority tetragonal zirconia (t-ZrO₂) in topcoat (YSZ). No remarkable cracking was developed in the topcoat even after 60 hours of accelerated hot corrosion, which was attributed to the retention of in-relief t-ZrO₂ in YSZ.     

Preparation of asymmetric polysulfone/polyimide blended membranes for CO<Subscript>2</Subscript> separation

Asymmetric Flat sheet polysulfone-polyimide (PSF-PI) blended polymeric membranes (with PI content from 5–20%) have been fabricated following phase inversion technique. The membranes have been thoroughly characterized by the measurement of porosity, mechanical properties and also by SEM, FTIR and DSC analyses. With the increase in the PI content, the mechanical properties of the membranes, like Young’s modulus, tensile strength and elongation at break, increased. SEM investigations revealed that the surfaces of fabricated blended membranes possessed adequate homogeneity and their cross-sections showed non-porous top and diminutive porous substructure. From DSC analyses it has been observed that different compositions of the blended membranes exhibited single glass transition temperatures, implying proper compatibility of the polymers. The permeance of CO₂ and CH₄ through the membrane increased with the increase in PI content and it gradually decreased with the increase in the feed pressure in the range of 2–10 bar. Under the present investigation, the membrane with 20% PI content exhibited the maximum selectivity for the separation of CO₂/CH₄ gas mixes.