A Supervised Machine Learning Approach for the Credibility Assessment of User-Generated Content

Wireless Personal Communications - Consumers increasingly rely on online reviews to assist them in their buying decisions. The rising popularity of e-commerce websites, hotel reviews, and social...     

Automated Plant Leaf Disease Detection and Classification Using Fuzzy Based Function Network

Wireless Personal Communications - In recent years, the applications of the computer vision concepts and information communication technology has been observed in number of applications including...     

Experimental and numerical investigation of heat transfer in Li‐ion battery pack of a hoverboard

Li‐ion cells are used for energy storage and conversion in electric vehicles and a variety of consumer devices such as hoverboards. Performance and safety of such devices are severely affected by overheating of Li‐ion cells in aggressive operating conditions. Multiple recent fires and accidents in hoverboards are known to have originated in the battery pack of the hoverboard. While thermal analysis and measurements have been carried out extensively on large battery packs for electric vehicles, there is relatively lesser research on smaller devices such as hoverboards, where the extremely limited thermal management design space and the critical importance of user safety result in severe thermal management challenges. This paper presents experimental measurements and numerical analysis of a novel approach for thermal management of the battery pack of a hoverboard. Measurements indicate that temperature rise in cells in the pack can be as large as 30°C at 4C discharge rate, which, although unlikely to be a standard discharge rate, may result from a malfunction or accident. A novel thermal management approach is investigated, wherein careful utilization of air flow generated by hoverboard motion is shown to result in significant temperature reduction. Measurements also indicate the key role of the metal housing around the battery pack in thermal management. Measurements are found to be in good agreement with finite element simulations, which indicate that the battery pack can be cooled as effectively in presence of a perforated metal casing as without the casing at all. Experimental data and simulation model presented here offer critical insights into the design of hoverboard thermal management and may result in safer, high performance hoverboard battery packs.     

Improving photostriction of KNN-based ceramics by MnO2 additive and polarization

The effects of sintering additives on photostriction properties have been rarely reported and the polarization effect of KNN-based ceramics on the photostriction characteristics remains uncertain. In the present work, a highly feasible approach has been adopted to obtain improved photostrictive coefficient (α = 2.4 × 10^?9 m²/W) for KNN-based ceramics by adding appropriate amount (x = 0.5 wt%) of MnO₂ as sintering additives into 0.97(K_0.5Na_0.5)NbO₃-0.03(La_0.51Na_0.49)(Zr_0.54Ni_0.46)O₃ (97KNN-3LNNZ) ceramics. The appropriate amount of MnO₂ (x ≤ 0.5 wt%) in the ceramics does not alter the inherent multi-phase structure and results in uniform grain growth of the ceramics. The ferroelectricity and piezoelectricity can be optimized by the “softening” effect of Mn²⁺ and Mn³⁺ in KNN-based ceramics. The addition of MnO₂ increases energy band gap and also optimizes the optical absorption properties in the near-infrared band. 97KNN-3LNNZ+0.5 wt% MnO₂ ceramics show optimum overall performance. In addition to this, for x = 0.5 wt% sample, the power-dependent Raman spectra of ceramics measured before and after the electrical poling shows that the prior E-field poling can enhance the red shift corresponding to F_2g bending vibration mode. Subsequently, there are changes in bond angle of elements induced by light in oxygen octahedron. These phenomena play active roles in getting a deep understanding of the underlying mechanisms of photostriction for ferroelectric ceramics.     

A method for smoothing multiple yield functions

Many models of plasticity are built using multiple, simple yield surfaces. Examples include geomechanical models and crystal plasticity. This leads to numerical difficulties, most particularly during the stress update procedure, because the combined yield surface is nondifferentiable, and when employing implicit time stepping to solve numerical models, because the Jacobian is often poorly conditioned. A method is presented that produces a single C² differentiable and convex yield function from a plastic model that contains multiple yield surfaces that are individually C² differentiable and convex. C² differentiability ensures quadratic convergence of implicit stress-update procedures; convexity ensures a unique solution to the stress update problem, whereas smoothness means the Jacobian is much better conditioned. The method contains just one free parameter, and the error incurred through the smoothing procedure is quantified in terms of this parameter. The method is illustrated through three different constitutive models. The method's performance is quantified in terms of the number of iterations required during stress update as a function of the smoothing parameter. Two simple finite-element models are also solved to compare this method with existing approaches. The method has been added to the open-source “MOOSE” framework, for perfect, nonperfect, associated, and nonassociated plasticity.     

Dispersed beamforming approach for secure communication in UDN

Wireless communication systems are prone to many security breaches due to open nature of the medium and exponential a rise in subscribers. Hence, physical layer security (PLS) has emerged as one of the dominant low complexity alternatives to overcome the impact of eavesdropping by managing the physical characteristics of the medium. In this paper, we ensure PLS to moving users which tends to experience rise in handover, as a result of proximity between users and base station. This study is based on ultra-dense network (UDN). To tackle this challenge, novel secure beamforming named as beam broadening and beam merging have been proposed. Besides, we propose a synchronization approach called synchronized mobility clustering for UDN to reduce the overheads generated due to the exchange of information about moving users. More specifically, we derive an analytical expression for secrecy outage probability—an important security metric. The effect of proposed approaches have been validated through numerical results and the results show the effectiveness of the proposed approaches against eavesdropping. Finally, the performance of the proposed scheme is evaluated and compared with the conventional beamforming approach. However, this proposed approach works well for a varied density of users and location to be targeted.

     

An approach to enhance the photocatalytic activity of ZnTiO3

ZnTiO₃ nanoparticles and Ag-Fe co-doped ZnTiO₃ nanoparticles were prepared using sol–gel method. The prepared samples were annealed at 700 °C and showed pure hexagonal ZnTiO₃. All the samples were characterized by using X-ray diffraction (XRD), field-emission scanning electron microscope, energy-dispersive X-ray analysis, and UV analyses. The result showed that the hexagonal structure of Ag-Fe ZnTiO₃ is affected with the increase in Ag-Fe concentrations. The zinc titanate nanoparticles were used for determining the degradation of cationic dye. Photocatalytic activity of ZnTiO₃ nanoparticles was studied and compared with that of bare control. The results showed enhanced photocatalytic activity of the Ag-Fe co-doped ZnTiO₃ compared to pure ZnTiO₃, showing that the Ag-Fe co-doping deposition has a major function in enhancing the degradation capability of cationic dye.     

Performance Comparison Between Different Tunneling Techniques Using Different Routing Protocols

Wireless Personal Communications - Migration to IPv6 becomes a priority with the draining of IPv4 addresses. But both IPv4 and IPv6 have different structures, and directly bringing IPv6 into the...     

Unequal Clustering Protocols for Wireless Sensor Networks—Taxonomy,Comparison and Simulation

Wireless Sensor Network (WSN) consists of randomly distributed sensor nodes which can collect, process, route and transmit data from their respective environment. Most of the research on WSN is oriented towards optimizing utilization of finite resources of Sensor Nodes to increase the overall network operative time. Recent literature on WSNs reveals that hierarchical routing unequal clustering methodologies are gaining popularity due to energy efficiency, load balancing and scalability. In literature, numerous surveys on clustering methodologies are available which address different equal clustering methods. The unequal clustering protocols, which have their own attributes viz. balance load distribution, hot spot mitigation and energy efficiency, are comparatively less explored. This motivated us to undertake the present study on the taxonomy, comparison and simulation analysis of different methodologies pertaining to less explored unequal clustering protocols. Our base metrics for comparison of different unequal clustering protocols are scalability, energy efficiency & load balancing capability of the resulting network. A comprehensive discussion has also been presented to highlight the various advantages and disadvantages of different unequal clustering protocols. Further, we have summarized the study of unequal clustering protocols in the tabular form.