Multi-Parallel Adaptive Grasshopper Optimization Technique for Detecting Anonymous Attacks in Wireless Networks

Wireless Personal Communications - For a number of years, due to exponential increase in the demand for sustainable environment, suspicious activities have recently been identified as over-serious...     

Sharing Political Content in Online Social Media: A Planned and Unplanned Behaviour Approach

Human’s decision making is not necessarily always planned; their unplanned behaviour—determined by natural personality traits—also contributes to the decision making process. In this study, we investigate factors related to planned and unplanned behaviour to understand why people share political content in online social media. Based on an online survey of 257 social media users, our results demonstrate that the factors representing both planned (i.e., perceived social recognition and altruistic motivation) and unplanned behaviour (i.e., extroversion and impulsiveness) affect people’s political content sharing behaviour. Our study understands that sharing political content is not like sharing other forms of content such as tourist attractions—the former can provoke serious punishment in some countries. Accordingly, trait impulsiveness is negatively associated with political content sharing behaviour. We also found that collective opinion moderates people’s planned behaviour, but not their unplanned behaviour. In other words, personality traits are unaffected by others’ opinions, but traits that humans can control can be shaped by others’.     

Optimal estimation of interferometric phase for measuring surface deformation

In recent times, time-series interferometric synthetic aperture radar (InSAR) methods are developed to retrieve the deformation signal in non-urban areas from distributed scatterers (DS). Phase triangulation algorithm (PTA), an important step in these methods for filtering decorrelation noise from DS, aims at optimal estimation of the filtered wrapped interferometric phase values using InSAR data stack. The uniqueness of this research work lies in the incorporation of one such PTA only to provide an optimal set of wrapped interferometric phase values before phase unwrapping in the open source StaMPS processing environment. The proposed methodology, when adapted to measure surface deformation in Tehri reservoir rim region, Uttarakhand, India using Environmental Satellite (Envisat) C-band advanced synthetic aperture radar images, works efficiently and has enhanced the spatial coverage of measurement pixels compared to standalone PS-InSAR processing. It is also revealed from the one-dimension-line of sight velocity map that resulted velocity estimates are congruent with standalone PS-InSAR processing.     

Performance Enhancement of 5G OFDM Systems Using Modified Raised Cosine Power Pulse

Wireless Personal Communications - OFDM is a key modulation technology of current wireless communication systems such as 4G LTE/LTE-A. The fifth generation (5G) of wireless cellular networks is...     

A conceptual framework for the adoption of big data analytics by e-commerce startups: a case-based approach

Information Systems and e-Business Management - E-commerce start-ups have ventured into emerging economies and are growing at a significantly faster pace. Big data has acted like a catalyst in...     

Open data and its usability: an empirical view from the Citizen’s perspective

Government legislation and calls for greater levels of oversight and transparency are leading public bodies to publish their raw datasets online. Policy makers and elected officials anticipate that the accessibility of open data through online Government portals for citizens will enable public engagement in policy making through increased levels of fact based content elicited from open data. The usability and benefits of such open data are being argued as contributing positively towards public sector reforms, which are under extreme pressures driven by extended periods of austerity. However, there is very limited scholarly studies that have attempted to empirically evaluate the performance of government open data websites and the acceptance and use of these data from a citizen perspective. Given this research void, an adjusted diffusion of innovation model based on Rogers’ diffusion of innovations theory (DOI) is proposed and used in this paper to empirically determine the predictors influencing the use of public sector open data. A good understanding of these predictors affecting the acceptance and use of open data will likely assist policy makers and public administrations in determining the policy instruments that can increase the acceptance and use of open data through an active promotion campaign to engage-contribute-use.     

Effect of metallic interfacial layers on the properties of diamond-like carbon thin films

Diamond like carbon (DLC) thin films with metallic interfacial layers of aluminum and nickel-chromium (Al and Ni-Cr) were grown using a low cost hybrid technique involving a resistive heating thermal evaporator and radio frequency plasma enhanced chemical vapor deposition techniques. Stress, hardness, elastic modulus, bonding, phase, and electrical conductivity of these films were investigated. Introduction of interfacial Al and Ni-Cr layers in DLC led to drastic improvement of its conductivity along with a significant reduction in residual stress but with some reduction of hardness and the elastic modulus. The structural and surface properties of thin films were studied using X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques.     

Determination of Thermal Spray Coating Property with Curvature Measurements

Real-time curvature measurement of a coating-substrate system during deposition has facilitated the monitoring of coating stresses and provided additional insights into thermal spray deposition mechanisms. However, the non-equilibrium state of coating formation along with harsh spray booth environment introduces complexity not only in data interpretation but also in the coating properties estimation. In this paper, a new procedure is proposed to estimate the elastic modulus of thermal sprayed ceramic coatings using in situ curvature and temperature measurements. In order to correlate the measurable parameters to coating elastic modulus, a systematic study is conducted to develop a suitable methodology. First, various finite element model analyses are carried out to formulate suitable relations between the measurements and elastic modulus. Subsequently, experiments are conducted to validate the procedure to estimate coating moduli. The results are compared with more accurate measurements obtained from post-deposition characterization technique under low temperature thermal cycles. The comparison suggests that the moduli estimated using the proposed procedure are in good agreements with those obtained from the post-deposition technique. Further, the nonlinear response of coatings are evaluated from the estimated moduli during deposition and cool down, which offer additional information on the characteristics of thermal spray coatings.     

Glass/epoxy composites and aluminium alloy joint using Kevlar® intermediate layer and nanoclay-reinforced epoxy adhesive

Adhesive lap joint between glass fibre/epoxy composites and aluminium alloy (2014 T4) was prepared by an in situ moulding process using a matched die mould. The surface of aluminium alloy was treated with chromic acid before adhesive bonding. Lap shear strength and fatigue life were evaluated in tensile mode and tension–compression mode (at 40% of lap shear load of adhesive joint), respectively. Knurling on the surface of aluminium alloy improved the lap shear strength of the adhesive joint but did not influence the fatigue life of the same. Lap shear strength and fatigue life of adhesive joint made with neat epoxy adhesive and reinforcement of an intermediate layer of Kevlar^® between glass/epoxy composite and aluminium alloy were observed to be 0.44?kg/mm² and 3.6?×?10⁵ cycles, respectively. In another case, lap shear strength and fatigue life of similar type of adhesive joint made from nanoclay (Cloisite 30B)-reinforced epoxy adhesive and without reinforcement of an intermediate layer of Kevlar^® were observed to be 0.38?kg/mm² and 2.3?×?10⁵ cycles, respectively. Whereas, lap shear strength and fatigue life of adhesive joint made from nanoclay-reinforced epoxy adhesive along with the reinforcement of an intermediate layer of Kevlar^® were 0.48?kg/mm² and 3.9?×?10⁵ cycles, respectively. Therefore, adhesive joint made from nanoclay-reinforced epoxy adhesive along with the reinforcement of an intermediate layer of Kevlar^® was the best.     

Fracture Toughness of Plasma‐Sprayed Thermal Barrier Ceramics: Influence of Processing,Microstructure, and Thermal Aging

Fracture toughness of thermal barrier coatings (TBCs) has gained significant interest in recent years as one of the dominant design parameters dictating selection of materials and assessing durability. Much progress has been made in characterizing and understanding fracture toughness of relevant TBC compositions in their bulk form, but it is also apparent that the toughness is significantly affected by process‐induced microstructural defects. In this investigation, a systematic study of the influence of coating microstructure on the fracture toughness of atmospheric plasma‐sprayed TBCs has been carried out. Yttria partially stabilized zirconia (YSZ) coatings were fabricated under different process conditions inducing different levels of porosity and defect densities. Fracture toughness was measured on free‐standing coatings in as‐processed and thermally aged conditions using the double torsion technique. Results indicate significant variance in fracture toughness among coatings with different microstructures including changes induced by thermal aging. Comparative studies were also conducted on an alternative composition, Gd₂Zr₂O₇ which, as anticipated, shows significantly lower fracture toughness compared to YSZ. The results not only point toward a need for process and microstructure optimization for enhancing TBC performance, but also a framework for establishing performance metrics for promising new TBC compositions.