Chandigarh University

About: Chandigarh University is a education organization based out in Mohali, India. It is known for research contribution in the topics: Materials science & Computer science. The organization has 1358 authors who have published 2104 publications receiving 10050 citations.

A hybridized multi-algorithm strategy for engineering optimization problems

Abstract: This paper presents a new multi-hybrid algorithm (MHA) based on the hybridization concepts incorporated in the naked mole-rat algorithm (NMRA) The new algorithm uses the exploratory concepts of whale optimization algorithm (WOA), moth flame optimization (MFO) and marine predator algorithm (MPA) to enhance the worker phase or the exploration operation in NMRA In order to overcome the problem of local optima stagnation, a new stagnation phase inspired from the concepts of GWO and cuckoo search (CS) algorithm is also added Apart from these modifications, self-adaptivity has been incorporated by adapting all the parameters of the proposed algorithm Here five new mutation strategies including simulated annealing ( s a ), exponentially decreasing ( e x p ), chaos based ( c h a o t i c ), linearly decreasing ( l i n e a r ) and oscillatory inertia weight ( o s c i l l a t i n g ) have been exploited for different parameters of all the algorithms under study so that no user based parametric adjustments are required For performance evaluation, the MHA is subjected to CEC 2005, CEC 2014 benchmark problems and image thresholding problem The comparison on variable population sizes and dimension size has been done to prove the significance of the proposed algorithm over variable function evaluations and higher dimensional problems From the experimental results, it can be seen that proposed MHA performs better than adaptive differential evolution with optional external archive (JADE), self adaptive differential evolution (SaDE), opposition and exponential whale optimization algorithm (OEWOA), sine cosine crow search algorithm (SCCSA), fractional-order calculus-based flower pollination algorithm (FA-FPO), success-history based parameter adaption differential evolution (SHADE), SHADE with linear population size reduction hybrid with semi-parameter adaptation of CMA-ES (LSHADE-SPACMA), Laplacian biogeography-based optimization (LX-BBO), random walk grey wolf optimizer (RW-GWO), improved symbiotic organisms search (ISOS), variable neighbourhood bat algorithm (VNBA), improved elephant herding optimization (IMEHO) and others Statistical results in terms of Wilcoxon’s rank-sum test, Freidman’s test and convergence profiles further validate the superior performance of the proposed MHA algorithm The source code can be downloaded from https://githubcom/rohitsalgotra

Analytic and simulative comparison of turbulent FSO system with different modulation techniques

Abstract: In this paper, we characterize the performance of Intensity Modulation/Direct Detection (IM/DD) and coherent detection modulation techniques in free-space optical (FSO) communication system in terms of bit error rate (BER). The system of interest includes M-ary Pulse Position Modulation (M-PPM) in correspondence to IM/DD and M-ary Phase Shift Keying (M-PSK) and M-ary Quadrature Amplitude Modulation (M-QAM) with respect to coherent detection. The system is subjected to weak turbulence regime of log-normal channel with scintillation index less than 0.75. Coherent techniques involve the amount of signal pulses transmitted in a particular time as the major component of their generation, except IM/DD which is a result of photon intensity, i.e. the number of photons forming a pulse. It is worth mentioning that in previous studies, the performance of IM/DD techniques had been evaluated in terms of photon-count fluctuation statistics and thus the impact of fading strength of channel on signal intensity was not discussed anywhere. In this work, an objective equivalence has been achieved between these two kinds of detection by deriving the BER expression of M-PPM in terms of probability density function of signal intensity, while considering fading strength, scintillation index, thermal noise and outage probability as system parameters for numerical analysis.

Investigations on Melt Flow Rate and Tensile Behaviour of Single, Double and Triple-Sized Copper Reinforced Thermoplastic Composites.

Abstract: Thermoplastic composite materials are emerging rapidly due to the flexibility of attaining customized mechanical and melt flow properties. Due to high ductility, toughness, recyclability, and thermal and electrical conductivity, there is ample scope of using copper particles in thermoplastics for 3d printing applications. In the present study, an attempt was made to investigate the Melt Flow Index (MFI), tensile strength, and electrical and thermal conductivity of nylon 6 and ABS (acrylonitrile butadiene styrene) thermoplastics reinforced with copper particles. Thus, the experiments were conducted by adding different-sized copper particles (100 mesh, 200 mesh, and 400 mesh) in variable compositions (0% to 10%) to ABS and nylon 6 matrix. The impact of single, double, and triple particle-sized copper particles on MFI was experimentally investigated followed by FTIR and SEM analysis. Also, the tensile, electrical, and thermal conductivity testing were done on filament made by different compositions. In general, higher fluidity and mechanical strength were obtained while using smaller particles even with higher concentrations (up to 8%) due to improved bonding strength and adhesion between the molecular chains. Moreover, thermal and electrical conductivity was improved with an increase in concentration of copper particles.